mm IIHIIII3IIIIllgfllyllfllllfllflfllllflllllglllzllllll " ' LIBRARY _' Michigan State University This is to certify that the dissertation entitled Exploratory Synthesis of New M/Asty(Q = S, Se) Compounds with Thioarsenate and Selenoarsenate Ligands by the Hydro (Solvo) Thermal Technique presented by Jun-Hong Chou has been accepted towards fulfillment of the requirements for Doctor PhiIOSOphy degree in [Claim professor Ma) Iéjms MSU is an Affirmative Action/Equal Opportunity Institution 0-12771 PLACE ll RETURN BOX to remove thle checkout from your record. TO AVOID FINEB return on or before date due. DATE DUE DATE DUE DATE DUE I—Jl --— ___l ”God EXPLORATORY SYNTHESIS OF NEW M/Asty(Q = 8, Se) COMPOUNDS WITH THIOARSENATE AND SELENOARSENATE LIGANDS BY THE HYDRO(SOLVO)THERMAL TECHNIQUE By Jun-Hang Chou A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Chemistry 1995 ABSTRACT EXPLORATORY SYNTHESIS OF NEW M/Asty(Q = S, Se) COMPOUNDS WITH THIOARSENATE AND SELENOARSENATE LIGANDS BY THE HYDRO(SOLVO)THERMAL TECHNIQUE By Jun-Hong(Richard) Chou The hydro(solvo)thermal technique was explored to synthesize new metal/Asty (Q = 8, Se) compounds with thioarsenate and selenoarsenate ligands. With thioarsenate ligands, [AsxSy]“‘, we have synthesized eleven new compounds. The remarkable feature exhibited by the compounds described in this dissertation is the complex condensation reactions exhibited by the thioarsenate polyanions.(see eq 1-4) Asszsnz' + AsSZSHz' = [As285]" + st (Eq. 1) [As,s,]" + st =2 [ASZS4SH13' + H8“ (Eq. 2) [As,s.sn13' + AsstHz’ z: [AS38715' + 1125 (Eq. 3) [As3S7ls' + 1125 = [AS3868H14' + HS" (Eq.4) These condensation reaction were probably catalyzed by the protonation of the terminal sulfide groups. The compounds include (Ph4P)2[InAS3S7], (Ph4P)2[SnAS489], (Me4N)2Rb[BiA86812]. (Ph4P)2[NiAS4S 8]. (Me4N)2[M0202A82$ 7]. (Ph4P)2[Pt(AS3Ss)2l. (Ph4P)2K[Pt3(A834)3l. (Ph4P)2K[Pd3(AsS4)3]. (Ph4P)2[Hg2AS489], (Me4N)[HgAS385], and K[Ag3A5285]. Further exploration using selenoarsenate ligands, [AsxSey]“', has allowed us to investigate the coordination chemistry of the [AsxSey]“' with metals like Hg and Ag. These reactions have resulted in the formation of variety of new compounds including (Me4N) [H gA sSe3] , (EuNMHgAsSesl. (Ph4P)2[Hg2AS4Se11]. B-AgsAsScs. KslAngsssc9]. and (McsNHMAgaAszScsl. In this dissertation the synthesis, characterization and properties of the above compounds will be discussed. TO MY WIFE, HSUPING CHOU, AND CHILDREN, TIFFANY AND DANIEL CHOU ACKNOWLEDGMENT I sincerely like to thank my research advisor, Professor Mercouri G. Kanatzidis. No of the work described in this dissertation would have been possible without his patient guidance, encouragement, dedication, and support. I would also like to thank the other members of my committee: Professor H. A. Eick, Professor, J. McCracken, and Professor J. Allison. I would also like to express my appreciation to each member of the Kanatzidis group, past and present, for their kindness and friendship, which make my graduate school a wonderful experience. Finally, I would like to express my deepest gratitude to my wife, Hsu-Ping, and children, Tiffany and Daniel Chou, for their understanding and encouragement throughout this thesis work. Tiffany, we now can go to the Disney World like I promise you before. Financial support given by National Science Foundation, ACS-PRF, and Center for Fundamental Material Research, and the Department of Chemistry at Michigan State University are gratefully acknowledged TABLE OF CONTENTS Page LIST OF TABLES ......................................................................................................... x LIST OF FIGURES ..................................................................................................... xvii CHAPTER 1. A Review of Metal/[EnyP' Systems (E = As, Sb; Q = S, Se) .............. ' ......................................................................... 1 References .................................................................................................... 32 CHAPTER 2. HY DROTHERMAL SYNTHESIS OF M/ASxSy (M = 1113+, Sn“, Bi3+) COMPOUNDS. SYNTHESIS AND CHARACTERIZATION OF (Ph4P)2[InAS3S7], (Ph4P)2[SnAS489] AND (M64N)2Rb[BiA36812] ........... 37 1. Introduction ............................................................................................. 39 2. Experimental Section ........................................................................... 40 2.1 Reagents .................................................................................... 40 2.2 Syntheses .................................................................................. 4O (Ph4P)2[InA53S7] ................................................................. 41 (Ph4P)2[SnAs489] ................................................................. 41 (Me4N)2Rb[BiA55812] ......................................................... 41 2.3 Physical Measurements ...................................................... 41 2.4 X-ray crystallography ......................................................... 43 3. Results and discussion ......................................................................... 57 3.1 Syntheses and description of structures ...................... 57 3.2 Physicochemical studies ...................................................... 73 References ..................................................................................................... 85 vi CHAPTER 3. HYDROTHERMAL SYNTHESIS OF M/AsxSy (M = Ni2+, M05”) COMPOUNDS. SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (Ph4P)2[Ni2AS458l. and (Me4N)2[M0202A5287] ....................................................... 88 I. Introduction ............................................................................................ 9O 2. Experimental Section ........................................................................... 92 2.1 Reagents .................................................................................... 92 2.2 Syntheses .................................................................................. 92 (Ph4P)2[Ni2AS483] ................................................................ 92 (Me4N)2[M0202A5287] ........................................................ 93 2.3 Physical Measurements ...................................................... 93 2.4 X-ray crystallography ......................................................... 93 3. Results and discussion ...................................................................... 103 3.1 Syntheses and description of structures .................... 103 3.2 Physicochemical studies .................................................... 115 References......._ ............................................................................................. 122 CHAPTER 4. HYDRO(SOLVO)THERMAL SYNTHESIS OF DISCRETE MOLECULAR M/AsxSy (M = M, Pt2+ Pd2+) ANIONS. SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (Ph4P)2[Pt(AS335)2](I). (Ph4P)2K[Pt3(A834)3](H). AND (Ph4P)2K[Pd3(AsS4)3](III) .................................. 126 1. Introduction .......................................................................................... 128 2. Experimental Section ........................................................................ 129 2.1 Reagents ................................................................................. 129 2.2 Syntheses ............................................................................... 130 . (Ph4P)2[Pt(AS385)2] ......................................................... 130 vii (Ph4P)2K[Pt3(AsS4)3] ....................................................... 130 (Ph4P)2K[Pd3(AsS4)3] ...................................................... 130 2.3 Physical Measurements ................................................... 131 2.4 X-ray crystallography ....................................................... 131 3. Results and discussion ..................................................................... 145 3.1 Syntheses and description of structures ................... 145 3.2 Physicochemical studies ................................................... 159 References .................................................................................................. 167 CHAPTER 5 HYDROTHERMAL SYNTHESIS OF M/Asty (M = Hg2+, Q = S, Se) COMPOUNDS. SYNTHESIS AND CHARACTERIZATION OF (Ph4P)2[Hg2AS489](I), (MC4N)[H8A8356](H). (M64N)[H8ASSe3l(III). (Et4N)[H8ASSC3](IV). and (PMP)2[H82AS436111(V) 1. Introduction .......................................................................................... 173 2. Experimental Section ........................................................................ 174 2.1 Reagents ................................................................................. 174 2.2 Syntheses ............................................................................... 174 (Ph4P)2[Hg2AS489] ........................................................... 175 (Me4N)[HgAS385] .............................................................. 175 (Me4N)[HgAsSe3] .............................................................. 175 (Et4N)[HgAsSe3] ................................................................. 176 (Ph4P)2[Hg2AS48e1 1] ........................................................ 176 2.3 Physical Measurements ................................................... 176 2.4 X—ray crystallography ....................................................... 176 3. Results and discussion ...................................................................... 197 3.1 Syntheses and description of structures .................... 197 3.2 Physicochemical studies .................................................... 216 viii References ................................................................................................... 230 CHAPTER 6 HYDRO(METHANO)THERMAL SYNTHESIS OF M/Asty (M = Ag2+, Q = S, Se) COMPOUNDS. SYNTHESIS AND CHARACTERIZATION OF AgaAsSesfl). (MesNH)[Ag3Aszsesl(II). K5[Ag2AS3Se9](III), and K[Ag3A3285](IV) .............. 233 1. Introduction .......................................................................................... 236 2. Experimental Section ......................................................................... 238 2.1 Reagents ................................................................................. 238 2.2 Syntheses ............................................................................... 239 B-AgsAsSes ......................................................................... 239 (MegNI-I)[Ag3Aszses] ....................................................... 240 K5[Ag2AS3Se9] .................................................................... 240 K[Ag3A52$5] ........ - -- ............................. 241 2.3 Physical Measurements ................................................... 241 2.4 X-ray crystallography ........................................................ 241 3. Results and discussion ...................................................................... 255 3.1 Syntheses and description of structures .................... 255 3.2 Physicochemical studies .................................................... 292 References ................................................................................................... 303 CHAPTER 7 CONCLUSIONS ..................................................................... 306 References ................................................................................................... 313 ix 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 2-11 2-12 LIST OF TABLES Page Crystallographic Data for (Ph4P)2[InAS3S7](I), (Ph4P)2[SnAS489](II), and (Me4N)2Rb[BiA56812](III) ....... 46 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[InAS3S7] ............... 48 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[SnAS489] .............. 50 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Me4N)2Rb[BiAS58121 ....... 52 Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[InAS3S7] (I) .......................... 54 Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[SnAS489](II) ......................... 55 Calculated and Observed X-ray Powder Diffraction Pattern of (Me4N)2Rb[BiA86812](III) ............... 56 Selected Distances (A) in (Ph4P)2[InA33S7] with Standard Deviations in Parentheses ........................................................... 58 Selected Angles (Deg) in (Ph4P)2[InAsgS7] with Standard Deviations in Parentheses ........................................................... 59 Selected Distances (A) in (PhaP)2[SnAS489] with Standard Deviations in Parentheses ........................................................... 64 Selected Angles (Deg) in (Ph4P)2[SnAS4SO] with Standard Deviations in Parentheses ........................................................... 65 Selected Distances (A) in (Me4N)2Rb[BiAS5812] with Standard Deviations in Parentheses ....................................... 70 2-15 3-1 '3-2 3-3 3-4 3-5 3-6 3-7 3-8 3-9 3-10 Selected Angles (Deg) in (Me4N)2Rb[BiAS(,S12] with Standard Deviations in Parentheses ....................................... 70 Frequencies (cm'l) of Raman and Infrared Spectral Absorptions of (Ph4P)2[InAS3S7](I), (Ph4P)2[SnAs489](II), and (MeaN)2Rb[BiAs6S12](III) ................................................... 74 TGA data for (Ph4P)2[InAs3S7](I), (Ph4P)2[SnAS489](II), and (MeaN)2Rb[BiAS5812](III) ................................................... 76 Crystallographic Data for (Ph4P)2[Ni2AS483](I), and (MeaN)2[M0202Aszs7](II) ............................................................ 95 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[Ni2AS4Sg](I) ........ 96 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Me4N)2[M0202As287](II) .................. 98 Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[NiAS4Sg](I) .......................... 101 Calculated and Observed X-ray Powder Diffraction Pattern of (Me4N)2[M0202Aszs7](II) .............. 102 Selected Distances (A) in (PhaP)2[Ni2As483] with Standard Deviations in Parentheses ..................................... 107 Selected Angles (Deg) in (Ph4P)2[Ni2AS483] with Standard Deviations in Parentheses ..................................... 107 Selected Distances (A) in (Me4N)2[M0202A8287] with Standard Deviations in Parentheses ..................................... 111 Selected Angles (Deg) in (Me4N)2[M0202Aszs7] with Standard Deviations in Parentheses ..................................... 112 Frequencies (cm'l) of Infrared Spectral Absorptions of (Ph4P)2[NiAS4Sg](I), and (Me4N)2[M0202A3287](II) ........ 115 xi 3-11 4-1 4-2' 4-3 4-4 4-5 4-6 4-7 4-8 4-9 TGA Data for (Ph4P)2[NiAS483](I), and (MeaN)2[M0202Aszs7](II) .................................................. 117 Crystallographic Data for (Ph4P)2[Pt(AS385)2](I) and (PIMP)2K[PI3(ASS4)3]'1.5 H20(II) ............................................ 133 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[Pt(AS385)2](I)... 135 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2K[Pt3(AsS4)3]-l.5H20(II)... 137 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2K[Pd3(AsS4)3]-3CH3OH(III) ............... ....... - ......................... 139 Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[Pt(AS3Ss)2](I) ..................... 142 Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2K[Pt3(AsS4)3]-l.5H20(II). 143 Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2K[Pd3(AsS4)3]- 3CH3OH(III) ..................................................................................... 144 Selected Distances (A) in the [Pt(AS3SS)2]2' with Standard Deviations in Parentheses ......................................................... 147 Selected Angles (Deg) in the [Pt(AS3SS)2]2' with Standard Deviations in Parentheses ......................................................... 148 Selected Distances (A) in the [M3(AsS4)3]3' (M = Pt, Pd) with Standard Deviations in Parentheses ........................... 154 Selected Angles (Deg) in the [M3(ASS4)3]3' (M = Pt, Pd) with Standard Deviations in Parentheses ........................... 155 xii 4-12 4-13 5-2 5-3 5-4 5-5 5-6 5-7 5-8 5-9 5-10 5-11 Far-IR spectral Data for (Ph4P)2[Pt(AS3Ss)2](I), Ph4P)2K[Pt3(AsS4)3]-l.5 H2001), and (Ph4P)2K[Pd3(AsS4)3]-3 MeOH(III) ......................................... 161 TGA Data for (Ph4P)2[Pt(AS3S§)2](I), (Ph4P)2K[Pt3(AsS4)3] - 1.5HzO(II), and (Ph4P)2K[Pd3(AsS4)3] - 3MeOH(III) ...................................................................................... 162 Crystallographic Data for (Ph4P)2[Hg2AS489](I), MeaN)[HgAS385](II) ...................................................................... 179 Crystallographic Data for (Me4N)[HgAsSe3](III), (Et4N)[HgAsSe3](IV), and (Ph4P)2[Hg2Asase11)](V) ........ 181 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[Hg2As489] .......... 183 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Me4N)[HgA33$e6] ........... 185 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Me4N)[HgAsSe3] ............. 186 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Et4N)[HgAsSe3] ............... 187 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[Hg2AS4Se11] ...... 188 Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[Hg2AS489] ............................ 192 Calculated and Observed X-ray Powder Diffraction Pattern of (Me4N)[HgA8385] ............................... 193 Calculated and Observed X-ray Powder Diffraction Pattern of (MeaN)[HgAsSe3] ............................... 194 Calculated and Observed X-ray Powder xiii 5-13 5-14 5-15 5-16 5-17 5-18 5-19 5-20 Diffraction Pattern of (Et4N)[HgAsSe3] ................................. 195 Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[Hg2AS4Se11] ........................ 196 Selected Distances (A) in (Ph4P)2[Hg2AS489] with Standard Deviations in Parentheses ..................................... 198 Selected Angles (Deg) in (Ph4P)2[Hg2AS489] with Standard Deviations in Parentheses ..................................... 198 Selected Distances (A) in (Me4N)[HgA5386](II) with Standard Deviations in Parentheses ..................................... 203 Selected Angles (Deg) in (Me4N)[HgAS3S5](II) with Standard Deviations in Parentheses ..................................... 204 Selected Distances (A) and Angles (Deg) in (Me4N)[HgAsSe3] (III) and (Et4N)[HgAsSe3] (IV) with Standard Deviations in Parentheses ..................................... 208 Selected Distances (A) in (Ph4P)2[Hg2AS4Se11] with Standard Deviations in Parentheses ..................................... 212 Selected Angles (Deg) in in (Ph4P)2[Hg2AS4Se11] with Standard Deviations in Parentheses ..................................... 213 Frequencies (cm'l) of Raman and Infrared Spectral Absorptions of (Ph4P)2[Hg2AS489] (I), (Me4N)[HgAS385] (II), (Me4N)[HgAsSe3] (III), (Et4N)[HgAsSe3] (IV), and (Ph4P)2[Hg2AS43¢11] (V) ............................................................. 216 TGA Data for (Ph4P)2[ngAS4S9l (I). (Me4N)[H8A8336] (11). (Me4N)[HgAsSe3] (III), (Et4N)[HgAsSe3] (IV), and (Ph4P)2[ngAS48e11] (V) ............................................................. 220 Crystallographic Data for B-Ag3AsSe3(I) (MegNH)[Ag3AS28e5](II) ............................................................. 243 xiv 6-2 6-3 6-4 6-5 6-6 6-7 6-8 6-9 6-10 6-11 6-12 6-13 6-14 Crystallographic Data for K5[Ag2AS3$e9](III) K[Ag3Aszss](IV) ............................................................................. 244 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of B-Ag3AsSe3(I) .................. 245 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Me3NI-I)[AS3As28e5](II) ............................................................. 246 Selected Atomic Coordinates and Estimated _ Stande Deviations (esd's) of K5[Ag2AS3Se9](III) ......... 247 Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of K[Ag3A3285](IV) .............. 248 Calculated and Observed X-ray Powder Diffraction Pattern of B-Ag3AsSe3(I) .................................... 250 Calculated and Observed X-ray Powder Diffraction Pattern of(Me3NH)[AS3AS28e5](II) .................. 252 Calculated and Observed X-ray Powder Diffraction Pattern of K5[Ag2AS3Se9](III) ........................... 253 Calculated and Observed X-ray Powder Diffraction Pattern of K[Ag3AS285](lV) ................................ 254 Selected Distances (A) in B-Ag3AsSe3 with Standard Deviations in Parentheses ......................................................... 257 Selected Angles (Deg) in B-AggAsSe3 with Standard Deviations in Parentheses ......................................................... 258 Selected Distances (A) (with Standard Deviations in Parenthesesa) in the [AggAszse5]1° layer ........................... 268 Selected Angles (Deg) (with Standard Deviations in Parenthesesa) in the [Ag3Aszse5]1' layer ........................... 269 XV 6-15 6-16 6-17 6-18 6-19 7-1 7-2 7-3 7-4 7-5 Selected Distances (A) of K5[Ag2AS3Se9] with Standard Deviations in Parentheses ......................................................... 276 Selected Angles (Deg) of [Angs3Se9]5' with Standard Deviations in Parentheses ......................................................... 277 Selected Distances (A) in K[Ag3A3285] with Standard Deviations in Parentheses ......................................................... 285 Selected Angles (Deg) in [Ag3AS285]1' with Standard Deviations (in Parentheses ........................................................ 286 Frequencies (cm-1) of Raman and Infrared Spectral Absorptions of AggAsSe3 (I), (Me3NH)[Ag3AS28e5] (II), K5[Ag2AS3Se9] (III), and KlAggAszss] (IV) ......................... 292 Various [AsxSyPI' polyanions .................................................. 308 Various [AsxSeyP' polyanions ................................................ 308 Various [AstyP' (Q = 8, Se) anions found in this work .................................................................................................... 309 Different binding modes found in the [AstyP' anions ........................................................................... _ ....... 310 Some other known [AstyPl' (Q = S, Se, Te) anions ....... 311 xvi 1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9 1-10 1-11 1-12 l-l3 1-14 1-15 1-16 1-17 LIST OF FIGURES Page Structure of [A56S12]5' anion ........................................................ 3 Structure relation of [PbS3] layers and [TlSs] chains in PleAs385 .............................................................................................. 4 The square pyramidal ribbon of M85 (M = Pb, Sb) in Pb/Sb/S sulfosalts ............................................................................ 6 Packing diagram of Ag7Sz(AsS4) viewed down the 0 axis .......................................................................................................... 7 (A) Structure of [SAsS7]' anion. (B) Packing diagram of (Ph4P)[SAsS7].... - _ -- - - ............ 9 The structure of [As(Se2)(Se)]' infinite chain found in compounds MAsSeg (M = K, Rb, Cs) .......................................... 11 Two views of the [AS385J3' anion .............................................. 12 Structure of the [AS485]2‘ anion ................................................ 14 Structure of the [Sb128e20]4‘ anion .......................................... 15 (A) Structure of Cp'3Ti20(AsS3). (B) Structure of the [M0202A84814]2' anion ................................................................... 17 Structure of the [Se=W(PSe4)(PSe2)]' anion ......................... 18 Structure of the [W2A328e13]2' anion ...................................... 20 Structure of the [MoAszse10]2' anion ...................................... 21 Structure of the [M(CO)2(AS3SC3)]2' (M = W, Mo) anion.. 23 Ortep drawing of a [AsgS13]2' layer in CszAs3813 .............. 26 Ortep drawing of a [A88S13]2‘ chain in szAsgs13 ............. 27 (A) View of KCuzAsS3 down the b axis showing the copper arsenic sulfide connectivity in a layer. xvii 1-18 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 2-11 3-1 3-2 3-3 3-4 (B) View of KCuzAsS3 down the c axis .................................... 29 Packing diagram of KCu4AsS4 ..................................................... 30 Structure and labeling scheme of [InAS3S7]n2"' ................ 60 Packing diagram of (Ph4P)2[InAS3S7]. (A) view down the c-axis. (B) view down the b-axis ............................................. 61 Strucuture and labeling scheme of [SnAS459]n2“' ............. 66 Packing diagram of (Ph4P)2[SnAS489]. (A) Showing the crossing section. (B) Showing the One-dimensional chains. - -- . ..................................... 67 Structure and labeling scheme of one [BiA35812]n3n' layer ............................................................... 71 Packing diagram of (M64N)2Rb[BiA55812] .............................. 72 Far-IR spectra of (A) (Ph4P)2[InAs3S7], (B) (Ph4P)2[SnAS489], and (C) (MC4N)2Rb[BiAs(5812] ................. 75 TGA diagrams of (A) [InAS3S7] and (B) (PhaP)2[SnAS439] ....................................................................... 77 TGA diagram of (MeaN)2Rb[BiAs5812] ..................................... 78 Optical absorption spectra of (A) (Ph4P)2[InAS387], and (B) (Ph4P)2[SnAS489] .............................................................. 80 Optical absorption spectrum of (Me4N)2Rb[BiA35812] ...... 81 Structure and labeling scheme of one [NiA3483],,2"' chain .............................................................. 106 Packing diagram of (PhaP)2[NiAS483]. (A) view down the a-axis. (B) view down the c-axis... 107 Structure and labeling scheme of one [M0202AS287],.2"' chain .............................................................. 1 13 Packing diagram of (Me4N)2[M0202A5287] ......................... 114 xviii 3-5 3-6 3-7 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 5-1 5-2 5-3 5-4 5-5 5-6 5-7 Far-IR spectra (CsI pellets) of (A) (Ph4P)2[NiAS483], and (B) (MC4N)2[M0202ASZS7] ........................................................... 116 TGA diagrams of (A) (Ph4P)2[NiAs483], and (B) (Me4N)2[M0202A5287] .................................................................. 1 18 Optical absorption spectra of (A) (PhaP)2[NiAS483], and (B) (Me4N)2[M0202A8287] .................................................................. 1 19 Packing diagram of (Ph4P)2[Pt(As385)2] .............................. 149 Structure and labeling scheme of [PtAsaSmP' ................. 150 Packing diagram of (Ph4P)2K[Pt3(AsS4)3] ........................... 156 Structure and labeling scheme of {Pt3(AsS4)3]3‘ ............. 157 Structure and labeling scheme of [Pd3(AsS4)3]3‘ ............ 158 Far-IR spectral Data for (A) (Ph4P)2[Pt(A3335)2](I), (B) (Ph4P)2K[Pt3(AsS4)3]-l.5 H2001), and (C) (Ph4P)2K[Pd3(AsS4)3]-3 MeOH(IlI) .................................. 160 TGA diagrams of (A) (Ph4P)2[Pt(A5385)2](I), (B) (Ph4P)2I([Pt3(AsS4)3]-l.5 H20(II) ............................................ 163 TGA diagram of (Ph4P)2K[Pd3(AsS4)3]-l.5 HzO(III) ........ 164 Packing diagram of (Ph4P)2[Hg2AS489] ................................ 199 Structure and labeling scheme of one [ngAS489lnzn' chain ........................................................... 200 Packing diagram of (MeaN)[HgAS3S(5] ................................... 205 Structure and labeling scheme of one [HgAS385],."' layer ............................................................... 206 Packing diagram of (Me4N)[HgAsSe3] ................................... 209 Structure and labeling scheme of one [HgAsSe3],."' chain .............................................................. 210 Packing diagram of (Ph4P)2[Hg2AS4$e11] ............................ 214 xix 5-8 5-9 5-10 5-11 5-12 5-13 5-14 5-15 5-16 6-2 6-3 6-4 6-5 Structure and labeling scheme of one [ngAS48e11]n2"' chain ...................................................... 215 Far-IR spectra of (A) (Ph4P)2[Hg2A5489](I), (B) (Me4N)[HgAS356](II) ..................................................................... 217 Far-IR spectra of (A) (Me4N)[HgAsSe3](III), (B) (Et4N)[HgASSesl(IV). and (C) (Ph4P)2[ngAS4SCll](V)m 218 TGA diagrams of (A) (Ph4P)2[Hg2AS4S9](I), (B) (MeaN)[HgAS385](II) ..................................................................... 221 TGA diagrams of (A) (Me4N)[HgAsSe3](III), (B) (Et4N)[HgAsSe3](IV) ..................................................................... 222 TGA diagram of (Ph4P)2[Hg2AS4Se11] ................................... 223 Optical absorption spectra of (A) (Ph4P)2[Hg2AS489](I), (B) (Me4N)[HgAS3S5](II) ............................................................. 225 Optical absorption spectra of (A) (Me4N)[HgAsSe3](III), (B) (Et4N)[HgAsSe3](IV) .............................................................. 226 Optical absorption spectrum of(Ph4P)2[Hg2AS48e11](V) .......................................................... 227 Structure and labeling scheme of Ag3AsSe3. (A) B—form. (B) a-form .............................................................. 259 Stereoview of the fi-AggAsSe3 (I) .......................................... 261 Packing diagrams of B-AggAsSe3(I). (A) view down the b- axis. (B) Stereoview down the b-axis. (C) view down the c-axis. (D) Stereoview down the c-axis ............................... 262 (A). Structure and labeling scheme of one [Ag3Aszse5]' layer. (B) Stereoview .................................................................. 270 Packing diagrams of (Me3NH)[Ag3Aszse5](II). (A) view down the c-axis. (B) view down the a-axis ...................... 272 XX 6-6 6-7 6-8 6-9 6-10 6-11 6-12 6-13 6-14. 6-15 6-16 6-17 6-18 6-19 Packing diagram of (Me3NH)[Ag3Aszse5](II) showing the hydrogen bonding between the Sc and H .......................... 274 Structure and labeling scheme of one [AngS3Se9]n5n' layer ........................................................ 278 Packing diagram of K5[Ag2AS3Se9]. (A) view down the 3- axis. (B) view down the b-axis ............................................... 279 The coordination environments of K+ in K5[Ag2AS3Se9]. The open circles represent Se atoms .................................... 282 (A) Structure and labeling scheme of one [Ag3A5285]nn' layer. (B) Stereoview .................................................................. 287 Packing diagram of K[Ag3A5285]. (A) view down the b- axis. (B) view down the c-axis ................................................. 289 The coordination environments of K+ in K[Ag3A8285]. The open circles represent S atoms ...................................... 291 Far-IR spectra of (A) Ag3AsSe3. (B) (Me3NH)[Ag3AszSe5] .................................................................... 293 Far-IR spectra of (A) K5[Ag2AS3Se9], (B) and K[Ag3Asst] -- -- - 294 Optical absorption spectra of (A) Ag3AsSe3(I) and (B) (Me3NH)[Ag3Aszse5](II) ............................................................. 296 Optical absorption spectra of (A) K5[Ag2AS3Se9](III) and (B) K[Ag3AS285](IV) ............................................................. 297 DTA data of Ag3AsSe3(I). (A) First cycle. (B) Second cycle ' - _ - -- 298 TGA diagram of B-Ag3AsSe3(I) ............................................... 299 TGA diagram of (Me3NH)[Ag3Aszse5] ................................... 300 xxi CHAPTER 1 A Review of Metal/[EnyPI- Systems (E = As, Sb; Q = S, Se) 'IU .11.. 4.. a l.‘ 2 The chemistry of metal/AsxSy has been studied in mineralogy for a very long time. There is a large number of minerals which belong to a class of structurally interesting compounds known as sulfosalts. These sulfosalts have the general formula of MxEsz (M = metal, E = As, Sb, Bi; Q = S, Se, Te). Examples include Ag3AsS3,1 Ag3AsSe3,2 Hng4Sg,3 TngAS3S5,4 T13ASS45, Pb3AS4Sg.6 There are several characteristic features in these compounds. First, the metals are usually soft heavy metals, like Ag, Tl, Pb, Au, Hg. Second, they ., often have very complicated 3-dimensional dense packed structures. Third, the building blocks are mostly thio- or seleno- arsenates and antimonates with tri- or pentavalent group 15 elements. The interest in the sulfosalts stems not only from their great structural diversity but also because of interesting physical properties that are Characteristic of these compounds. For example Ag3AsS3, and A g 3AsSe3 are well known for their nonlinear optical properties.7 Most of these compounds were formed in the earth's crust through the reaction of metal sulfides with group 15/16 sulfides at elevated temperatures or through hydrothermal reaction in superheated Water. From a synthetic point of view, this area of chemistry is relatively unexplored, although there is increasing evidence that more people are paying more attention to the mixed group 15/16 <-‘-hemistry. For example, Ag3AsSe3 does not occur in nature like the iSomorphous Ag3AsS3 (proustite, pyragyrite). It was synthesized by “Sing a mixture of Ag/As/Se in a sealed silica tube at 1000 °C.8 Another example of a synthetic sulfosalt is PleAS386 which was .eeEa ALA—mama: of we 2325a A; ouewmm Ca V: 2 e, O O .2 Om a< . } [PDS‘gln layer . . ‘. }[T155] chains Figure 1-2. Structural relation of [Png] layers and [1185] chains in PleAS385, e L'.‘ 5 synthesized by using a mixture of T128/PbS/Aszs3 by a hydrothermal reaction.9 The structure contains unique chainlike [A86812]5‘ ligands; see Figure 1-1. The Pb is coordinated by seven S atoms forming PbS3 layers which are interconnected by T185 double chains; see figure 1- 2. The most studied system in sulfosalts, from a synthetic point of view, is probably the Pb/Sb/S system. A detailed phase diagram,10 published in 1979, indicated that six ternary compounds are possible between P138 and szS3: Pb7Sb4Sl3,11 Pb3Sb285,12 PbsSb4811 (boulangerite),13 Pb28b285,14 Pb4Sb5813 (robinsonite),15 and PbszS4 (Zinckenite).15 Three of them are known as natural minerals and the other three can be synthesized from elemental lead, antimony and sulfur in sealed silica tubes at temperatures in excess of 1000 °C. Recently, a number of compounds was reported in this system that were previously unknown including Pb58b5814,17 Pb7Sb4813,11 Pb4Sb4Se1o,18 and PbszSe4.19 They all have very complicated three-dimensional dense packed structures. The common feature of these compounds is the ribbons built of the square pyramid M85 (M = Pb, Sb), see Figure 1-3. Different width and binding modes of the ribbons give different structures. A unique modification of the known sulfosalt, CuAngsS4, is seen in (NH4)Ag2AsS4.20 The sites that were previously held by the Cu atoms are now occupied by NH4+ cations. The compound was synthesized by using elemental Ag, As, S in a stainless steel autoclave with an ammonia solution (25%) at 220 °C. Also, The compound Ag7Sz(AsS4) has been synthesized by hydrothermal technique.“ There are three crystallographically independent Ag atoms which are surrounded by two, three, and four Figure 1-3. The square pyramidal ribbon Of M55 (M = Pb, Sb) in Pb/Sb/S sulfosalts. 8 S atoms. These Ag polyhedra and A584 tetrahedra form a three- dimensional framework, see Figure 1-4. The above examples suggest that the chemistry is very broad and structurally diverse, and that opportunities exist for synthetic chemists to explore for new materials ("synthetic minerals"). We have studied metal polychalcogenides in our lab for a long time. It has been demonstrated that polychalcogenide ligands of various chain lengths can act as building blocks and can connect .metal ions together to form compounds ranging from molecular complexes to one-dimensional, two-dimensional, and even three- dimensional solid state compounds.22 These polychalcogenide ligands can coordinate to virtually all metal ions. In addition, since each member of the chain contains at least two lone pairs of electrons, one or all members of polychalcogenide ligands can ligate the metal ions. Conceptually, the mixed [AsxSyP' anions can be viewed as an extension of the well-known polychalcogenide ligands, see Scheme 1, since the AS' ion is isoelectronic to S. The best example of this concept is the compound (Ph4P)[SAsS7], see Figure 1-5, prepared from the reaction of [A328C15]' and 852'.23 The eight-member crown shaped ring compound is isoelectronic with elemental 83. Because of the charge on the AS“ ion, the Ph4P+ cations are needed for charge balance. The introduction of the trivalent As element should dramatically increase the potential connectivity of the building blocks and lead to more complicated structures. (A) As (B) lgur . O a ‘I .‘J P4. 10 2- - H s S s/s\S/S S/ \‘Ais/ - S . Scheme 1-1 Despite the great potential for structural variation, the chemistry of the metal/AsxSy has not been as intensely studied as that of the metal/polychalcogenides. The simple reason may be the absence of suitable starting materials, in contrast to the polychalcogenide anions, which are soluble in polar organic solvents like DMF, so the chemistry can be easily carried out in solution. Also the alkali metal/polychalcogenides, Any, form melts at relative low temperature (200 0C to 600 0C), so reactions can be carried out in molten salts. The alkali metal/AsxSy system usually forms solid state compounds, which are not soluble in common organic solvents. For example, MAsSe324 and MAsSe225 ( M = K, Rb, Cs) all have one- dimensional chain-like structures. MAsSe3 (M = K, Rb, Cs) were prepared by hydrothermal reaction of the respective alkali carbonate with As2$e3 at a temperature of 135 °C. Their X-ray structural analyses revealed that the compounds contain polyselenoarsenate anion, (AsSe3)n“', in which As atoms are bonded with a terminal monoselenide and connected to the neighboring As atom through a diselenide. The compound can be best described as MAs(Se2)(Se); see Figure 1-6. The MAsSez (M = K, Rb, Cs) were prepared by methanothermal reaction of M2CO3 (M = K, Rb, Cs) with Aszse3 at a temperature of 130 °C. The structures are basically the ll 0 S? 0 A54 5 Q S I) ) S Figure 1-6. The structure of [As(Se2)(Se)]' infinite chains found in the compounds MAsSe3 (M = K, Rb, Cs). 12 (A) $1 $1 $2 Figure 1-7. Two views of the [AS386]3' anion. 13 same as those of the MASSe3 but the diselenides are now replaced by monoselenides. There are a variety of synthetic methods to prepare the mixed [AsxSyP' anions; most of them involve some kind of a nucleophilic attack. For example ethylenediamine can react with AS283 to give [AS33613‘.26 The structure of [A5385]3' is shown in Figure 1-7. It contains discrete cyclic [AS385J3' anions with a six-member AS383 ring in the chair conformation. Similarly, piperidine can attack AS484 to form the thioarsenate anion [AS486]2', see Figure 1-8.27 It is also a molecular compound with discrete [AS486]2’ anions. The structure of the [AS485]2' anion is related to that of AS484 by replacement of an As-As bond with two [As-ST units. By using the same principle, the selenium analog can also be synthesized with ethylenediamine and AS4Se4 in DMF.28 Simple reduction of the binary phases with alkali metals also yields some interesting results. For example, As2Te3 reacts with K 'in ethylenediamine and with Ph4P+ to yield (Ph4P)2[As10Te3].29 Recently, Kolis and coworkers reported that simple reduction of antimony selenide in DMF by using potassium metal leads to formation of a salt with the formula (Ph4P)4[8b128e2()],3o see Figure 1-9. By the classical definition, this is the largest molecular Zintl ion characterized. Rauchfuss and co-workers reported the isolation of a compound with the formula Cp'3Ti2O(AsS3) (Cp' = 115-CH3C5H4).31 This compound which contains [A383]3' ligands bridged across two Ti centers used all three 8 atoms. The lone pair on the As atom is not involved with the bonding to metal ions. It also contains an oxo bridge which could 14 Figure 1-8. Structure of the [A5486]2' anion. 15 Figure 1-9. Structure of the [Sb128e20]4’ anion. 16 have come from the solvent. This is an important compound because it demonstrates that molecular [AsxSy]n' anions can act as ligands toward transition metals, see Figure 1-10(A). In the same paper, they also found that tetrathiomolybdate, M08423 acts as a nucleophile and attacks AS484 to form the complex [MO2O2AS4814]2', see Figure 1-10(B). The origin of the oxo group probably is adventitious water in the solvent. This compound contains the highly unusual [AS4812]4‘ ligand and further indicates the great potential new chemistry that [AsxSyP' can provide. Kolis et al. also have also contributed toward the related class of [PxSeyP' ligands. They found that W8e42' readily attacks P48e4 glass to form the first reported metal phosphorus selenide compound, (Ph4P)2[8e=W(P8e4)(PSe2)], see Figure 1-11.32 It represents the first example of a coordinated [P8e4]3' ligand. It also contains the highly unusual side-bonded [PSe2]' group. Related reactions of M08e42' and W8e42' with AS48e4 in DMF also lead to a series of novel clusters.33 (Ph4P)2IWSC4] + AS4864 (Ph4P)2[W2(fl-SC)3(ASSCs)2] (Ph4P)2[MoSe4] + AS48e4 (Ph4P)2[Mo(AsSes)2] 17 (A) Figure 1-10. (A) Structure of Cp'3Ti20(As83). (B) Structure of the [M0202AS4S14]2’ anion. 18 Pill Sel2l Figure 1-1 1. Structure of the [Se=W(PSe4)(PSez)]' anion. 19 The [W2A82S613]2' anion consists of two tungsten centers each of which is ligated by six selenium atoms in an irregular coordination environment; see Figure 1-12. Three selenides bridge the metal centers, and each tungsten atom is also ligated by a tridentate AsSes group. The overall shape of each fragment is that of a "bird cage" similar to the familiar AS48e3 shape. Each tridentate fragment can be considered a trianion, making the tungsten atoms formally 5+. The 'w-w distance is 2.903 A, which is well within accepted bonding distance. The [MoAs28e10]2' anion is a monomer with Mo in the 4+ oxidation state (see figure 1-13). It contains one molybdenum atom chelated by two AsSe5 groups. The fact that the tungsten ion in [W2A528e13]2' has a 5+ oxidation state is probably because tungsten is much harder to reduce than molybdenum. It was also found that many of the soluble anionic clusters will react with metal carbonyls to form novel transition metal complexes. This so-called oxidative decarbonylation reaction is well known for polychalcogenide ligands and metal carbonyls.34 Now it can be extended to the [AsxSeyP' anions.35 [NF II M(C0)s + [As28c612° (M(AsSe5)2]2° (M: Mo, W) M H M(C0)s + [Asiscslz' [M(CO)2(As3Se3)2]2' (M = M0, W) 20 s m Soul scum 5.111] e e ‘ - 5.1.3 ' ‘ 3 § '7/\ ‘ \‘Ié \\ . ~ . I)... 4‘ V" solzl v12! R 4:, WV hem \'-\ R a J ”’A‘ Sea 1“Sure 1-12. Structure of the [WzASZSeBP‘ anion. 21 Figure 1-13. Structure of the [MOASZSelo]2' anion. 22 The molecule [WAs28e10]2' is isostructural with a molybdenum analog shown above. The [M(CO)2(AS3SC3)]2' ( M = W, Mo) anion contain a central metal atom which is coordinated by two arsenic and one selenium atom of two identical AS3Se3 ligands; see Figure 1-14. Each ligand cage combines with the metal to complete the formation of two corner-sharing birdcage structures. The two cages are related by two noncrystallographic mirror planes passing through the center of the molecule. There are also two CO molecules coordinated to the metal. The geometry around the metal can best be described as bicapped trigonal prismatic. There is an increasing interest in developing new and unusual synthetic techniques to help stabilize new compounds that otherwise might not be possible by traditional methods. Recently, a great deal of attention has been paid to the use of superheated fluids as a synthetic technique.36 Superheated fluids are solvents which are heated above their boiling point, with enough pressure to keep them in the fluid state. There are several advantages offered by superheated fluids. The solubility and the activities of the reactants are greatly increased with the elevation of temperature. The superheated fluids promote. crystal growth which is very important for characterization since the isolated compounds are usually new materials, and single-crystal X-ray analysis is essential. The operating temperatures are below those used for molten salt reactions. This technique gives access to a lower temperature regime where metastable compounds that were previously unreachable can now be accessed. Water is the most common fluid in this method, 23 0‘21 AetJt Ae‘l $0121 “151 om Mm Figure 1-14. Structure of the [M(CO)2(AS3S€3)]2’ (M =- W, MO) anion. 24 but recently a variety of other solvents have been used successfully as well. Schiifer et al. have prepared a large number of ternary alkali metal antimony sulfides using the hydrothermal technique. The dimensionality of these compounds extends from molecular to three- dimensional. Examples include CS28b3813,37 K2Sb487,38 K2Sb487.H20,39 a,B-Rb28b487,40 C528b487.41 The last four compounds, although isoelectronic, all have different structures. These results demonstrate the broad structural flexibility of the A/Sb/S (A: alkali metal) system. Sheldrick et al. have investigated the M/15/16 system (M = alkali metal) using superheated water and methanol and have shown that a host of ternary phases can be prepared by reacting alkali metal carbonate with binary 15/16 phases.42'47 For example: 175°C/MeOH Rb2C03 + Sb28e3 : RbSb3865 140°C/MeOI-I Rb2C03 + Sb233 : Rb28b48e7 130°C/MeOH C82C03 + ASZSC3 t CsAsScz This technique has led to a wide variety of new ternary phases with structures that range from one-dimensional infinite chains to two-dimensional layers to very complicate three-dimensional 25 structures. Two examples, C52A5381343 and Rb2AsgSl3,49 demonstrate this astonishing structural diversity. CS2A53813 is prepared hydrothermally at 180 °C and possess a two-dimensional layered structure. The X-ray structure analysis revealed that the polyanion (A83813)n2n' is composed of individual AS484 eight-member rings, which are each connected to three other rings via As-S-As bridges, giving rise to an infinite layered structure; see Figure 1-15. Rb2A33813 is also prepared hydrothermally at 200 °C. The polyanion (AS3813)n23' is composed of AS383 six-member rings, which are connected to one another via bridging AsS3 pyramids, giving rise to an infinite one-dimensional double chain structure; see Figure 1-16. The main structural differences between CS2AS3813 and Rb2A53813 arise from the two different AsxSy rings, AS484 and AS383. This may be explained by the cation size effect. The larger AS484 eight- member rings, whose sizes were just right for Cs cations, were stabilized by the larger Cs cations while the Rb cations stabilized the smaller AS383 six-member rings. Recently, the same methodology was adopted by Parise et at. with small modification. They used tetraalkyl ammonium ions, Instead of alkali metals, as the counterions. With the large counterions more open frameworks can be attained. Examples include (Me4N)[8b385],50 (Et4N)[Sb385], and (N2C4H3)[8b487].51 (Et4N)[Sb385], and (N2C4H3)[Sb487] are layered compounds with the organic cation Sitting between the layers. In the case of [8b385]n“', a counterion size effect is observed. The smaller tetramethylammonium salt, (Me4N)[Sb385], has a three-dimensional 26 Figure 1-15. Ortep drawing of a [ASBSBP' layer in CSzA53813. 27 S A ’W .8 As 3 As 05 V: I " I IS I I As 5 S ()S A, As A C - O V 3 Figure 1-16. Ortep drawing of a [AS3813]2' chain in Rb2A53813. 28 structure while the large tetraethylammonium salts, (Et4N)[Sb385], possesses a two-dimensional layered structure. Kolis et al. have demonstrated recently that superheated ethylenediamine is also a suitable solvent for synthesis of new metal mixed15/16 compounds. They have synthesized two new quaternary phases by reaction between KAs82 and Cu powder in superheated ethylenediamine.52 300°C Cu + KAss2 I" : KCuZAs83 + KCu4As84 The KCu2AsS3 compound possesses a two-dimensional layered structure with the Kcations situated in the gallery region. Each layer is a complex structure consisting of formal Cu+ ions linked in a complicated manner by a series of trigonal AsS33' groups; see Figure 1-17. One unusual feature of this compound is that Cu(l) and Cu(2) are tetrahedrally coordinated by three three sulfur atoms and the lone pair from the arsenic atoms of an A5833’ group. The KCu4ASS4 compound has an extremely compicated three-dimensional structure with copper ions ligated by A5833‘ groups as well as 82' ions; see Figure l-l8. The development of useful technologies often depends on the availability of the solid-state materials with appropriate physical and chemical properties. The exploratory synthesis of these new materials is often accomplished by traditional high-temperature fusion reactions method. This method has led to several discoveries with great potential impact on technology ranging from the high- temperature superconductors to the next-generation nonlinear 29 (A) (B) Figure 1-17. (A) View of KCuzAsS3 down the b axis showing the copper arsenic sulfide connectivity in a layer. (B) View Of KCuzAsS3 down the caxis. 3O Figure 1-18. Packing diagram of KCU4ASS4. 31 optical materials. However, new synthetic methodologies are needed to advance solid-state chemistry. From all the results presented above, the chemistry of MxEsz (M = metal; E = As, Sb, Bi; Q = 8, Se, Te) shows great promise for discovering new materials. 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Anorg. Allg. Chem. 1986, 535, 179- 185. Sheldrick, W.; Kaub, J. Z. Naturforsch. 1985,40b, 1130-1133. Sheldrick, W.; Kaub, J. Z. Naturforsch. 1985,40b, 571-573. Parise, J. B. Science, 1991, 251, 293-294. Parise, J. 8.; KO, Y. Chem. Mater. 1992, 4, 1446-1450. Jerome, J. E.; Wood, P. T.; Pennington, W. T. Kolis, J. W. Inorg. Chem. 1994,33, 1733-1734. 37 CHAPTER 2 HYDROTHERMAL SYNTHESIS OF M/AsxSy (M = In3+, Sn“, 313+) COMPOUNDS. SYNTHESIS AND CHARACTERIZATION OF (Ph4P)2[InAS3S7], (Ph4P)2[SnAS489] AND (Me4N)2Rb[BiA85812] 38 ABSTRACT By using hydrothermal synthesis technique (Ph4P)2[InAS3S7], (Ph4P)2[SnAS489],and (Me4N)2Rb[BiAs(5812] were synthesized from mixtures of InCl3/2K3As83/4Ph4PBr, Sn82/3K3As83/4Ph4PBr, and BiCl3/2Rb3AsS3/4Me4NCl, respectively. (Ph4P)2[InAS3S7] crystallizes in the monoclinic space group P21/c (No. 14) with a = 19.078(9) A, b = 14.436(3) A, c = l9.325(6) A, B=lO6.11(3)°, V = 5111(4) A3,z = 4. [InAS387]n2"' is a one-dimensional chain structure consisting of trigonal bipyramidal In3+ ions and [AS387]5' units formed by comer- sharing [As83]3' units. (Ph4P)2[SnAS489] crystallizes in the triclinic space group P-1(No. 2) with a = 13.476(3) A, b = 18.365(5) A, c = 11.343(2) A, a = 107.28(2), a = 96.90(3)°,y = 9692(2), v = 5111(4) A3,Z = 2. [SnAS489]n2"' also has a one-dimensional chain structure with octahedral Sn4+ ions and [AS489]6’ units formed by corner- sharing [AsS3]3' units. The mixed salt (Me4N)2Rb[BiAs6812] crystallizes in the trigonal R-3(h) space group (No. 148) with a = 9.978(1) A, c = 28.337(5) A, V = 2356(1) A3, 2 = 3. [BiAS5812]n3"’ possesses a two-dimensional structure. Three As atoms and six 8 atoms form a unique cyclic [AS386]3' unit in a chair conformation, which is connected to three Bi atoms via terminal 8 atoms. The Bi3+ is in a nearly perfect octahedral geometry. The Me4N+ and Rb+ cations reside in the interlayer gallery. The Rb+ cations are coordinated to six 8 atoms, forming a trigonal antiprism. The solid state optical spectra of these compounds are reported. 3‘9 1. Introduction Several important classes of solid-state compounds such as silicate, borate, and phosphate minerals contain building blocks which are assembled from the condensation of elementary units like SiO44', BO33'- PO43', etc.1 This condensation gives rise to a large variety of rings, chains, and layers and results in great structural diversity among these minerals. By comparison, condensation in main-group thiometalates is less common. Examples include ternary thioborates,2 thiogermanates,3 and thioarsenates.4 An elementary structural unit which may have great potential for condensation is the pyramidal As833' unit. This condensation properity is demonstrated in species such as [A53813]2' ,5 [AS486]2' ,5 and [AS386]2'.7 Similar units were recently reported to occur in the molecular compounds [M(CO)2(AS3Se3)2]2' (M = M0, W),3 [M0202AS481412' .9 [MoAszselolz'u and [W2A82861312'.‘° From the examples above, it is clear that the thioarsenic anions are interesting ligands and excellent building blocks for potentially to an enormous variety of complexes and solids. With this in mind, we initiated exploration of the systems R4E+ (R = alkyl, Ph; E = N, P)/M"+/ASS33' ( M = main group element) using hydrothermal technique with the aim of obtaining novel frameworks containing either A5833' or its condensates. We report here our initial results from this promising approach,11 which include the isolation of three new polymeric compounds, (Ph4P)2[InAS3S7](I), (Ph4P)2[SnAS489](II), and (Me4N)2Rb[BiAs6812](III). 4O 2. Experimental Section 2.1 Reagents Chemicals. Chemicals in this work, other than solvents, were used as obtained. (i) BiCl3, 98% purity, InCl3, 99% purity, tetraphenylphosphonium bromide (Ph4PBr), 98% purity, tetramethylammonium chloride, (Me4NCl), 99% purity, Aldrich Chemical Company, Inc., Milwaukee, WI. (ii) sulfur powder, sublimed, J. T. Baker Chemical CO., Phillipsberg, NJ. (iii) potassium metal, analytical reagent, Mallinckrodt Inc., Paris, KY; (iv) arsenic sulfide, AS283, ~100 mesh, 99% purity, Cerac Inc. Milwaukee WI. (v) Methanol, anhydrous, Mallinckrodt Inc., Paris, KY; diethyl ether, AC8 anhydrous, EM Science, Inc., Gibbstown, NJ. 2.2 Syntheses All syntheses were carried out under dry nitrogen atmosphere in 3 Vacuum Atmosphere Dri-Lab glovebox except where specifically indicated otherwise. A3AsS3 (A = K, Rb, Cs) were synthesized by using stoichiometric amounts of alkali metal, arsenic sulfide (AS283), and sulfur in liquid ammonia. The reaction gives a yellow brown powder upon evaporation of ammonia. (Pb4P)2[InAS3S7]: A Pyrex tube (.4 mL) containing lnCl3 (55 mg, 0.25 mmol), K3AS83 (144 mg, 0.5 mmol), Ph4PBr (419 mg, 1.0 mmol), and 0.5 mL of water was sealed under vacuum and kept at 120 °C for 2 days. The large pale yellow transparent chunky crystals 41 were isolated in water and washed with methanol and ether (yield 74.5 % based on In). SEM/EDS analysis on these crystals showed a P:In:As:S ratio of 1.6:1:1.4:7.2. (Ph4P)2[SnAS489]: A Pyrex tube (.4 mL) containing 8n82 (55 mg, 0.25 mmol), K3ASS3 (144 mg, 0.5 mmol), Ph4PBr (419 mg, 1.0 mmol), and 0.5 mL of water was sealed under vacuum and kept at 120 °C for 2 days. The large orange transparent chunky crystals were isolated in water and washed with methanol and ether (yield 74.5 % based on Sn). SEM/EDS analysis on these crystals showed a P:Sn:As:S ratio of 1.6:1:1.2:6.2. (Me4N)2Rb[BiAS5812]: BiCl3 (63 mg, 0.2 mmol) was mixed with 2 equiv of Rb3As83 (171 mg, 0.4 mmol) and 4 equiv of Me4NCl (88 mg, 0.8 mmol), and the mixture was sealed under vacuum with 0.3 mL of H20 in a Pyrex tube (.4 mL). The reaction was run at 120 °C for 1 week. 'Washing the reaction mixture with methanol and ether afforded dark red cube-like single crystals of (Me4N)2Rb[BiAS5812] (45 mg, yield of 30 % based on Bi). SEM/EDS analysis on these crystals showed a Rb:Bi:As:S ratio of 1:1.1:8:7.2. 2.3. Physical Measurements FT-IR spectra of compounds were recorded as a solid in a CSI matrix. The sample was ground with dry Csl into a fine powder, and a pressure of about seven metric tons was applied to the mixture to make a translucent pellet. The spectra were record in the far-IR region (600-100 cm'l, 4 cm'1 resolution) with the use of a Nicolet 740 FT-IR spectrometer equipped with a TGS/PE detector and silicon 42 splitter. Raman spectra were recorded at room temperature with a Nicolet FT -Raman 950 spectrometer. Quantitative microprobe analysis of the compounds was performed with JEOL JSM-35CF scanning electron microscope (SEM) equipped with a Tracor Northern Energy Dispersive Spectroscopy (EDS) detector. Single crystals of each sample were mounted on an aluminum Stub which was coated with conducting graphite paint to avoid charge accumulation on the sample surface under bombardment of the electron beam during measurements. Energy Dispersive Spectra (EDS) were obtained by using the following experimental set-up: X-ray detector position: 55 mm Take-off angle: 27 deg Working distance: 39 mm Beam current: 200 picoamps Accelerating voltage: 20 kv Accumulation time: 60 sec. Window: Be Optical diffuse reflectance measurements were made at room temperature with a Shimadzu UV-3101PC double beam, double- monochromator spectrophotometer. The instrument was equipped with an integrating sphere and controlled by a personal computer. The measurement of diffuse reflectivity can be used to obtain values for the band gap which agree rather well with values obtained by absorption measurements from single crystals of the same material. The digitized Spectra were processed using the KaleidagraphTM software program. BaSO4 powder was used as reference (100% 43 reflectance). Absorption data were calculated from the reflectance data by using the Kubelka-Munk function: 12 (l-R)2 “IS- 2R R is the reflectance at a given wavelength, (1 is the absorption coefficient and S is the scattering coefficient. The scattering coefficient has been shown to be practically wavelength independent for particles larger than 5 um which is smaller than the particle size of the samples used here. Thermal Gravimetric Analysis (TGA) was performed on a Shimadzu TGA-50. The samples were heated to 800 °C at a rate of 10 °C/min. under a Steady flow of dry N2 gas. Differential thermal analysis (DTA) was performed with a computer-controlled Shimadzu DTA-50 thermal analyzer. The ground single crystals were sealed in quartz ampules under vacuum. An quartz ampule of equal mass was sealed and placed on the reference side of the detector. The samples were heated to the desired temperature at 5 °C/min, then kept at that temperature for 10 min followed by cooling at 10 °C/min to 100 °C and finally rapid cooling to room temperature. 2.4. X-ray crystallography (Ph4P)2[InAS3S7]: The plate-like pale yellow crystal used for the study had approximate dimensions of 0.35 x 0.33 x 0.75 mm. The crystal was sealed inside a thin-walled glass capillary under air 44 and mounted on a goniometer head. Single-crystal X-ray diffraction data were collected at 23 °C on a Rigaku AFC6 diffractometer. A total of 8227 reflections were collected. All the nonhydrogen atoms except carbon were refined anisotropically. All hydrogen atom positions were calculated by assuming idealized geometry. Hydrogen atom contributions were included in the structure factor calculations, but their coordinates and temperature factors were not refined. (Ph4P)2[SnAS489]: A well Shaped orange crystal with _ dimensions of 0.45 x 0.35 x 0.5 mm was mounted on a glass fiber. Single-crystal X-ray diffraction data were collected at 23 °C on a Rigaku AFC6 diffractometer. A total of 7220 reflections were collected. All the nonhydrogen atoms except carbon were refined anisotropically. All hydrogen atom positions were calculated and fixed without further refinement. (Me4N)2Rb[BiAs(5812]: The single-crystal diffraction data were collected by Crystallics Compouny. A well shaped dark red cube-like crystal with dimensions of 0.34 x 0.45 x 0.521 mm was sealed inside a thin-walled glass capillary with epoxy. The crystal was oriented with an edge nearly parallel to the \y axis of the diffractometer. Single-crystal X-ray diffraction data were collected at 23 °C on a computer-controlled four-circle Nicolet (Siemens) autodiffractometer. A total of 1233 reflections were collected. All nonhydrogen atoms except carbon were refined anisotropically. All hydrogen atom positions were calculated and fixed without further refinement. 45 The crystals did not Show any significant decay as judged by three check reflections measured every 150 reflections throughout the data collection. The space group was determined by systematic absences and intensity statistics. The structures were solved by direct methods (SHELXS-86)13 with the TEXSAN software package14 and refined by full matrix least-squares methods. An empirical absorption correction (DIFABS)15 was applied to the isotropically refined data. All non-hydrogen atoms except nitrogen and carbon were refined anisotropically. All calculations were performed on a VAXstation 3100 Model 76 computer. Table 2-1 summarizes the crystallographic data and details of the structure solution and refinement. The final atomic coordinates with their estimated standard deviation (esd's) are given in Table 2-2, 2- 3, and 2-4. Table 2.1 Crystallographic 46 Data for (Ph4P)2[InA8387l(I). (Ph4P)2[SnAS489](II), and (Me4N)2Rb[BiAs6S12](III). I I I Formula C43H40P2InAS3S7 C43H40P2SnAS489 F. w. 1241.59 1384.38 a, A 19.079(9) 13.476(2) b, A 14.436(3) 18.365(3) c, A 19.325(6) 11.348(2) 01, deg. 90.00 107.28(2) 8, deg. 106.11(3) 96.90(2) y, deg. 90.00 96.92(2) 2, v, A3 4, 5111(4) 2, 2626(2) Space Group P21/c (No. 14) P-I (NO. 2) color, habit pale yellow, plate orange, plate Dealt g/cm3 1.62 1.75 Radiation Cu K01 Mo K01 them-1 94.61 34.22 20max, deg. , 120.0 45.0 Absorption Correction \|I scan \v scan Transmission Factor 0.71-1.40 0.83-1.15 Index ranges 05h521,05kgl6, 05h_<_16,-225_k_<_ -22_<_15,22 22,-13gl_<_13 NO. of Data coll. 8227 7220 Unique reflection 7971 6863 Data Used 3604 3891 (Fo2 > 30(Fo2)) No. of Variables 550 340 Final R'lwa, % 5.5/5.7 4.9/6.2 a R: 2(lFol-ch|)/2|Fol, b Rw={I.'.w(|Fo|-|I'7c|)2/23w|Fo|2}1/2 Table 2-1 (cont) I II Formula C3H24N2RbBiAS5812 F. w. 1201.98 a, A 9.978(1) b, A 9.978(1) c, A 28.337(5) 01, deg. 90.00 8, deg. 120.00 7. deg. 90.00 z,v, A3 3, 2356(1) Space Group R-3 (No. 148) color, habit dark red block Deal. g/cm3 2.73 Radiation Mo Kai u.cnr1 141.34 20m“, deg. 58.7 Absorption Correction \v scan Transmission Factor 0.745-1.000 Index ranges No. of Data coll. Unique reflection Data Used (F02 > 30(F02» No. of Variables Final Ralwa, % 0_<_hgl3,05ks_ll,0$lg34 1233 1157 906 40 3.1/2.5 11 R: 2(lFol-ch|)/£|Fol, b Rw={Zw(|Fo|-|Fc|)2/2wlFo|2} 1/2 48 Table 2-2. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[InAS3S7] atom X Y Z BCLav (A2) In 0.77261(5) 0.19922(6) 0.35422(4) 3.82(4) A81. 0.78622(9) 0.2030(1) 0.54266(7) 4.48(7) A82 0.8320(1) 0.2241(1) 0.71648(8) 4.48(7) A83 0.6873(1) 0.0363(1) 0.4239(1) 5.47(8) SI 0.7896(2) 0.3053(2) 0.4582(2) 4.7(2) S2 0.6496(2) 0.1254(3) 0.3249(2) 5.5(2) S3 0.7510(2) 0.3362(2) 0.2642(2) 5.0(2) S4 0.8045(2) 0.0439(2) 0.4341(2) 5.3(2) S5 0.8706(2) 0.1614(2) 0.2956(2) 4.8(2) S6 0.7641(2) 0.3088(3) 0.6215(2) 5.3(2) S7 0.6741(2) 0.1362(2) 0.5114(2) 5.5(2) P1 0.8830(2) -0.1772(2) 0.2150(2) 4.2(2) P2 0.3851(2) 0.3795(2) 0.6678(2) 4.2(2) C1 0.9335(7) -0.1653(8) 0.3083(7) 3.7(6) C2 0.9812(8) -0.2310(9) 0.3417(7) 5.0(7) C3 1.0214(8) -0.218(1) 0.4139(8) 5.7(7) C4 1.0137(8) -0.140(1) 0.4478(8) 6.0(8) C5 0.968(1) -0.074(1) 0.416(1) 9(1) C6 0.927(1) -0.085(1) 0.346(1) 9(1) C7 0.8859(7) -0.2957(9) 0.1900(7) 4.3(1) C8 0.901(1) -0.320(1) 0.127(1) 8(1) C9 0.896(2) -0.414(1) 0.107(1) 12(2) C10 0.876(1) -0.478(1) 0.147(1) 8(1) C11 0.8612(8) -0.456(1) 0.207(1) 5.3(8) C12 0.8661(8) -0.3629(9) 0.2304(7) 4.5(7) C13 0.7879(8) -0.145(1) 0.1972(7) 4.7(7) C14 0.763(1) 0.072(2) 0.225(1) 11(1) C15 0.692(1) -0.049(2) 0.206(1) 12(2) C16 0.642(1) -0.098(2) 0.160(1) 9(1) C17 0.664(1) -0.173(1) 0.131(1) 11(1) C18 0.737(1) -0.196(1) 0.149(1) 8(1) C19 0.9256(8) -0.1048(8) 0.1632(7) 4.0(6) C20 0.8922(9) -0.024(1) 0.132(1) 6.1(8) C21 0.928(1) 0.032(1) 0.097(1) 8(1) C22 0.997(1) 0.011(1) 0.092(1) 7(1) C23 1.030(1) -0.069(1) 0.123(1) 7(1) C24 0.995(1) -0.126(1) 0.1595(9) 5.9(8) 49 C25 0.4498(8) 0.296(1) 0.6543(8) 4.7(7) C26 0.518(1) 0.323(1) 0.655(1) 6.4(9) C27 0.567(1) 0.260(1) 0.646(1) 8(1) C28 0.551(1) 0.171(2) 0.635(1) 9(1) C29 0.487(1) 0.144(1) 0.638(1) 16(2) C30 0.434(1) 0.207(1) 0.645(2) 14(2) C31 0.4034(8) 0.485(1) 0.629(1) 5.0(7) C32 0.404(1) 0.490(1) 0.558(1) 9(1) C33 0.416(1) 0.569(2) 0.525(1) 12(1) C34 0.422(1) 0.647(2) 0.561(2) 12(2) C35 0.422(2) 0.649(2) 0.633(2) 13(2) C36 0.410(1) 0.566(1) 0.665(1) 9(1) C37 0.3934(7) 0.3925(8) 0.7619(8) 4.3(7) C38 0.3356(8) 0.429(1) 0.7840(9) 5.3(8) C39 0.341(1) 0.444(1) 0.855(1) 6.3(9) C40 0.405(1) 0.423(1) 0.9057(9) 5.9(8) C41 0.464(1) 0.387(1) 0.8856(9) 5.6(8) C41 0.4571(7) 0.371(1) 0.8135(9) 4.8(7) C43 0.2939(8) 0.347(1) 0.6225(8) 4.8(7) C44 0.269(1) 0.261(1) 0.625(1) 10(1) C45 0.197(1) 0.238(2) 0.589(2) 16(2) C46 0.152(1) 0.303(3) 0.553(1) 11(1) C47 0.174(1) 0.386(2) 0.551(2) 13(2) C48 0.2464(9) 0.411(1) 0.585(1) 10(1) 3 B¢q=(4/3)[a2811 + b2822 +c2B33 + ab(cosy)812 + ac(cosB)Bl3 + bc(cosa)B23] .50 Table 2-3. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[SnAS489] atom X Y Z ng 3, (A2) Snl 0.5000 0.0000 0.5000 2.04(6) Sn2 1.0000 0.5000 0.5000 2.44(6) Asl 0.7788(1) 0.3623(1) 0.5155(2) 3.03(7) A82 0.2450(1) -0.0252(1) 0.4641(2) 3.16(7) A83 1.2120(2) 0.4386(1) 0.4124(2) 4.9(1) A84 0.6563(1) 0.1887(1) 0.5132(2) 2.70(7) SI 0.3622(3) 0.0594(3) 0.6098(4) 3.1(2) SZ 0.6509(3) 0.0698(3) 0.6710(4) 2.9(2) S3 0.8812(3) 0.3728(2) 0.3813(4) 3.6(2) ‘ S4 1.0880(4) 0.4785(3) 0.3092(4) 4.3(2) S5 1.1332(4) 0.4272(3) 0.5668(5) 4.1(2) S6 0.6661(3) 0.2597(2) 0.3797(4) 3.5(2) S7 0.2130(3) -0.1246(3) 0.5434(5) 3.6(2) S8 0.5184(3) 0.1095(2) 0.4002(4) 2.5(2) S9 0.6743(4) 0.4484(3) 0.5012(5) 4.6(2) P1 0.2250(3) 0.0449(2) 1.0017(4) 2.3(2) P2 0.2804(3) 0.4128(3) 0.9216(4) 2.8(2) C1 0.189(1) -0.0558(9) 0.993(1) 2.3(3) (2 0.195(1) -0.111(1) 0.884(1) 3.8(4) C3 0.165(1) -0.189(1) 0.876(1) 4.2(4) C4 0.128(1) -0.203(1) 0.970(1) 4.2(4) C5 0.124(1) -0.153(1) 1.079(2) 3.9(4) C6 0.154(1) -0.0759(9) 1.090(1) 2.7(3) C7 0.356(1) 0.0699(8) 0.997(1) 2.1(3) C8 0.398(1) 0.029(1) 0.898(2) 3.2(2) C9 0.497(1) 0.051(1) 0.886(2) 3.4(4) C10 0.553(1) 0.115(1) 0.968(2) 3.3(4) C11 0.515(1) 0.157(1) 1.069(2) 4.6(4) C12 0.415(1) 0.135(1) 1.083(2) 4.2(4) C13 0.153(1) 0.0586(9) 0.868(1) 2.7(3) C14 0.191(1) 0.118(1) 0.827(2) 3.6(4) C15 0.139(1) 0.129(1) 0.722(2) 4.4(4) C16 0.050(1) 0.080(1) 0.660(2) 4.2(4) C17 0.016(1) 0.022(1) 0.700(2) 3.7(4) C18 0.066(1) 0.010(1) 0.806(2) 3.3(4) C19 0.194(1) 0.1044(8) 1.141(1) 2.4(3) C20 0.118(1) 0.151(1) 1.139(2) 3.1(3) C21 0.098(1) 0.199(1) 1.250(1) 4.1(4) 51 C22 0.151(1) 0.203(1) 1.363(2) 4.4(4) C23 0.223(1) 0.157(1) 1.368(2) 5.1(5) C24 0.247(1) 0.110(1) 1.259(2) 3.3(4) C25 0.344(1) 0.3773(9) 0.790(1) 2.6(3) C26 0.376(1) 0.427(1) 0.725(2) 3.6(4) C27 0.426(1) 0.395(1) 0.620(2) 4.4(4) C28 0.441(1) 0.319(1) 0.591(2) 4.0(4) C29 0.411(1) 0.274(1) 0.658(2) 3.6(4) C30 0.364(1) 0.303(1) 0.762(2) 3.5(4) C31 0.297(1) 0.5160(8) 0.979(1) 2.2(3) C32 0.262(1) 0.554(1) 0.900(2) 3.4(4) C33 0.272(1) 0.635(1) 0.945(2) 4.5(4) cs4 0.313(1) 0.675(1) 1.071(2) 4.7(4) C35 0.342(1) 0.636(1) 1.147(2) 4.4(4) C36 0.335(1) 0.554(1) 1.103(2) 4.3(4) C37 . 0.147(1) 0.3757(9) 0.875(1) 2.7(3) C38 0.106(1) 0.324(1) 0.759(2) 3.1(3) C39 0.001(1) 0.303(1) 0.730(2) 4.8(4) C40 -0.060(1) 0.329(1) 0.814(2) 4.8(4) C41 -0.021(2) 0.384(1) 0.926(2) 5.4(5) C41 0.083(1) 0.407(1) 0.959(2) 3.9(4) C43 0.333(1) 0.3771(9) 1.042(1) 2.8(3) C44 0.439(1) 0.395(1) 1.081(2) 3.8(4) C45 0.486(1) 0.372(1) 1.175(2) 4.2(4) C46 0.425(1) 0.331(1) 1.233(2) 4.3(4) C47 0.322(1) 0.312(1) 1.197(2) 4.2(4) C48 0.276(1) 0.337(1) 1.101(2) 3.4(4) 1‘ B¢q=(4/3)[a2B11 + b2822 +c2B33 + ab(cosy)B12 + ac(cosB)B13 + bc(cosol)Bz3] 52 Table 2-4. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Me4N)2Rb[BiAS5812] atom X Y Z Big 3, (A2) Bi 0.0000 0.0000 0.0000 l.01(2) Rb 0.0000 0.0000 0.5000 5.00(8) As 0.28307(8) -0.16664(1) 0.02659(3) 1.30(2) Sl 0.2390(2) 0.0110(2) 0.05874(7) l.71(6) S2 0.5102(2) -0.1047(2) 0.06797(8) 1.74(6) N 0.000 0.000 0.1928(5) 2.7(3) C1 0.000 0.000 0.2453(4) 0.9(2) CZ -0.155(1) -0.033(2) 0.1739(4) 5.5(5) 3‘ B¢q=(4/3)[a2B11 + b2B22 +czB33 + ab(cosy)B12 + ac(cosB)Bl3 + bc(cosa)Bz3] 53 The compounds were examined by X-ray powder diffraction to determine phase purity and for identification. Accurate dhkl spacings (A) were obtained from the powder patterns recorded on a calibrated (with FeOCl as internal standard) Phillips XRG-3000 computer-controlled powder diffractometer with graphite- monochromated Cu K01 radiation operating at 35 kV and 35 mA. The data were collected at a rate of 0.12°/min. Based on the atomic coordinates from X-ray single crystal diffraction study, X-ray powder patterns for all compounds were calculated, by the software package CERIUS.16 Calculated and observed X-ray powder patterns that Show d-spacings and intensities of strong hkl reflections are complied in table 2-5 to 2-7. 54 Table 2-5. Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[InA83871 (I) h It I 43L, (A) 41),, (A) 1mm (obs, %) 1 0 0 18.3 18.2 8 0 l 1 11.4 11.2 100 1 1 0 11.3 2 0 0 9.27 9.15 46 2 0 -2 7.67 7.59 10 1 0 7.48 7.35 10 0 2 7.22 7.15 16 2 1 1 6.61 6.55 13 1 2 -1 6.53 6.45 35 2 2 0 5.67 5.64 13 3 1 0 5.62 5.59 30 3 2 0 4.66 4.65 22 0 1 4 4.41 4.41 11 1 2 4 3.65 3.65 10 1 3 -5 3 00 3.00 12 0 4 5 2.587 2.575 8 55 Table 2-6. Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[SnAS4S9I(II) h k l at,“ (A) am (A) I/Imobs, %) 1 -1 0 11.4 11.3 62 0 0 10.7 10.6 100 1 9.82 9.78 11 0 2 8.67 8.65 75 1 -1 1 8.07 8.01 65 1 -1 -1 7.54 7.50 71 2 0 0 6.61 6.55 21 1 -3 1 5 54 0 2 -2 5.37 5.35 27 0 0 2 5.34 5.30 52 1 3 0 5.01 1 -1 2 4.97 4.97 50 1 -1 -2 4.71 4.71 18 0 4 -1 4.54 4.54 21 2 0 -2 4.51 4.51 17 3 1 0 412 2 4 0 3.39 3.37 10 3 3 1 2.929 2.927 13 0 6 3 2.697 2.697 12 56 Table 2-7. Calculated and Observed X-ray Powder Diffraction Pattern of (Me4N)2Rb[BiAS5812](III) h k I am (A) 4“,, (A) [Immbs %) 0 0 3 9.44 9.43 100 1 0 2 7.28 7.27 35 1 1 0 4.90 4.88 20 1 0 5 4.71 4.70 33 2 0 4 3.64 3.64 10 1 1 6 3.40 3.40 30 1 0 8 3.27 3.25 15 2 1 1 3.19 3.18 20 2 1 1 3.13 2 1 4 2 921 2.92 75 2 1 7 2.51 2 1 8 2 377 237 10 4 1 0 1.851 57 3. Results and discussion 3.1 Syntheses and description of structures (Ph4P)2[InAS3S7] was prepared by heating InCl3 with K3As83 and Ph4PBr in H20 at 120 °C. The compound, formed as pale yellow platelike crystals, and does not dissolve in common organic solvents consistent with a polymeric compound. The structure was determined by X-ray Single-crystal diffraction analysis. [InAS3S7],.2"' has an unusual one-dimensional polymeric structure composed of In3+ ions and [AS387]5' units form by comer-sharing pyramidal [AsS3]3' units, see Figure 2-1. The [AS3S7J5' units engage in a remarkably complex multidentate coordination with two In3+ centers, using all five of their terminal sulfur atoms. To the best of our knowledge, the [A83S7]5' unit represents a new thioarsenate anion with potentially rich coordination chemistry. The In3+ ion is in a distorted trigonal bipyramidal environment with the axial bond angle, S3—In-84, at l7l.4(l)°. For comparsion, in indium/polysulfide systems, the In usually adopts tetrahedral geometry; examples include [In2814]2' and [ln281(5]2'.18 In fact, trigonal bypyramidal indium polychalcogenide compounds are quite rare. Examples include [In28e21]4', ‘7 and [In2(84)2(86)2(87)]4'.13 It is interesting to point out that there are two six membered InAS283 rings, formed as the result of the [AS387]5' unique binding mode, in the structure. These two six membered rings share 5 of the six atoms and as a result of that, one adopts a chair conformation while the other one has the boat conformation. The average distance between the In and 58 the axial S atoms(82 and s3), at 2.642(4) A, is significantly longer than that between the equatorial S atoms, at 2.489(4) A. The [InAS3S7lnzn' chains lie parallel to the crystallographic c axis and are separated by Ph4P+ cations; see Figure 2-2(A) and (B). There are two types of As-S bonds in [AS357]5‘ unit. The average As-S distance of the type As-s_ln, at 2.216(4) A, is slightly Shorter than that of the AS-S-As type, at 2.279(4) A. The S—As—S angles range from 95.3(1) to 107.8(1)°. The bond distances and angles are comparable to those in [M0202AS4814]2’ and [MO404AS4S]4]4'.9 Selected bond distances and bond angles are given in Table 2-8 and 2-9. Table 2-8. Selected Distances (A) in (Ph4P)2[InAS3S7] with Standard Deviations in Parentheses!il In - s1 2.474(4) Asl - S7 2.271(5) In - 82 2.496(4) As2 - s3 2.189(4) In - S3 2.589(3) As2 - S5 2.234(4) In - S4 2.696(4) As2 - S6 2.285(4) In - 35 2.499(4) As3 - S2 2.251(4) Asl - S1 2.214(4) As3 - S4 2.192(5) Asl - S6 2.276(4) AS3 - S7 2.287(4) aThe estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {2n(ln - 1)2/n(n-l)}1/2,-where In is the length (or angle) of the nth bond, l the mean length (or angle), and n the number of bonds. Table 2-9. Selected Angles (Deg) in (Ph4P)2[InAS3S7] with Standard Deviations in Parentheses.a Sl - In - 82 110.6(1) S3 - A52 - 85 98.3(1) 81 - In - S3 91.8(1) S3 - A52 - 86 104.0(2) Sl — In - S4 95.3(1) 85 - A52 - S6 99.1(1) Sl - In - 85 123.8(1) 82 - A53 - S4 97.2(2) 82 - In - S3 102.1(1) 82 - A53 - S7 101.0(2) 82 - In - S4 79.8(1) 84 - A53 - S7 102.7(2) 82 - In - 85 125.3(1) In - Sl - Asl 99.2(1) S3 - In - S4 171.4(1) In - 82 - A53 89.6(1) S3 - In - 85 82.2(1) In - 83 - A52 88.8(1) S4 - In - SS 89.9(1) In - S4 - A53 85.8(1) 81- A51 - S6 95.3(1) In - 85 - A52 90.1(1) SI - Asl - S7 107.8(1) Asl — S6 - A52 90.5(1) S6 - Asl - S7 97.3(2) Asl - S7 - A53 100.2(2) aThe estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {Zn(ln - l)2/n(n-l)}1/2, where In is the length (or angle) of the nth bond, l the mean length (or angle), and n the number of bonds. 60 Figure 2-1. Structure and labeling scheme Of [InA5387ln 211'. 61 I Figure 2-2. Packing diagram of (Ph4P)2[InAS3S7]. (A) view down the c—axis. (B) view down the b-axis. 62 (B) 63 (Ph4P)2[SnAS489](II) was prepared hydrothermally by heating 8n82 with K3A583 and Ph4PBr in H20 at 120 °C for four days. The reaction was initially run with the 8n82/K3A583/Ph4‘PBr ratio of 1:2:2 and gave a low yield. We later discovered that excess of cation, Ph4PBr, not only increased the yield but also helped crystal growth which indicated that the Ph4PBr is not just a cation but also a mineralizer. The compound does not dissolve in common organic solvents such as CH3CN, DMF, and DMSO. The structure was determined by X-ray single-crystal diffraction analysis. [SnA5489]n2"' also has a one-dimensional polymeric chain-like structure composed of Sn“ ions and [A5489]5' units formed by corner-Sharing pyramidal [A583]3‘ units; see Figure 2-3. The [AS4S9]6' units,which can be viewed as the further condensation product between the [A5387]5' unit and [A583]3' unit, use all their six terminal sulfur atoms connecting two Sn4+ centers together. The [AS489]5' also represents a new thioarsenate anion. When comparing the bonding modes of the two thioarsenate polyanions, [A5387]5' and [AS489]6', we see the [AS387]5' units, in (Ph4P)2[InA5387], use two and three terminal sulfur atoms at either end of the units to bond metal ions, while the [AS4S9]6' units, in (Ph4P)2[SnAS489], have only one bonding arrangement. The [8nA5489],.2"’ chains are well separated by Ph4P+ cations, see Figure 2-4(A) and (B). The 8n“+ is in a distorted octahedral environment with the Sl-Sn-82 bond angle at 177.8(1)°. The average Sn-S distance at 2.550(4)A is very close to those found in K28n83.2H20,19 at 2.571A, which is in the range of typical Sn-S distances in SnS6 octahedra. The average S-As-S angle 64 Table 2-10. Selected Distances (A) in (Ph4P)2[SnAS489] with Standard Deviations in Parentheses.“ Snl - 8] 2.535(4) A52 - 81 2.213(5) Snli- 82 2.548(4) A52 - 82 2.243(5) Snl - 88 2.587(4) A52 - S7 2.281(5) Sn2 - S3 2.558(4) A53 - S4 2.244(6) Sn2 - S4 2.544(5) A53 - 85 2.210(5) Sn2 - 85 2.528(5) A53 - S9 2.298(5) Asl - S3 2.208(5) A54 - S6 2.279(5) Asl - S6 2.292(5) A54 - S7 2.287(5) Asl - S9 2.267(5) A54 - S8 2.209(4) 1‘The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {£n(ln - 1)2/n(n-1)}1/2, where 1,, is the Iength (or angle) of the nth bond, l the mean length (or angle), and n the number of bonds. 65 Table 2-11. Selected Angles (Deg) in (Ph4P)2[SnAS489] with Standard Deviations in Parentheses. 81 - Snl - 81 180.00 86 - Asl - S9 93.1(2) 81 - Snl - 82 98.2(1) 81 - A52 - 82 96.7(2) Sl - Snl - 82 81.8(1) Sl - A52 - S7 103.8(2) 81 - Snl - 88 90.6(1) 82 - A52 - S7 102.1(2) Sl - Snl - S8 89.4(1) 84 - A53 - 85 97.1(2) 82 - Snl - 82 180.00 84 - A53 - S9 101.0(2) 82 - Snl - 88 91.3(1) 85 - A53 - S9 104.5(2) 82 - Snl - S8 88.7(1) S6 - A54 - S7 95.9(2) 88 - Snl - 88 180.00 86 - A54 - S8 94.1(2) S3 - Sn2 - 83 180.00 87 - A54 - 88 104.8(2) S3 - Sn2 - S4 87.2(1) Snl - Sl - A52 90.2(2) S3 - Sn2 - S4 92.8(1) Snl - 82 - A52 89.1(2) 83 - Sn2 - 85 90.7(2) Sn2 - 83 - Asl 102.6(2) S3 - Sn2 - 85 89.3(2) Sn2 - S4 - A53 88.5(2) S4 - Sn2 - 84 180.00 Sn2 - 85 - A53 89.7(2) 84 - Sn2 - 85 82.3(2) A51 - S6 - A54 96.1(2) 84 - Sn2 - 85 97.7(2) A52 - 87 - as4 99.7(2) 85 - Sn2 - 85 180.00 Snl - 88 - A54 104.0(2) S3 - Asl - S6 96.2(2) Asl - 89 - A53 99.5(2) S3 - Asl - S9 103.1(2) 66 .-:~e_omvw<:m_ .0 2:05» wezonfi new. «SUP—em .m- am nm< N enema 67 (A) (A) Showing the Figure 2-4. Packing diagram Of (Ph4P)2[SnAS489]. crossing section. (B) Showing the One-dimensional chains. 68 (B) 69 and As-S distance are normal compare to those in other arsenic sulfide compounds.9 Selected bond distances and angles are given in Tables 2-10 and 2-11. When comparing the Structures of these two compounds, (Ph4P)2[InAS3S7] and (Ph4P)2[SnAS489], one can find several similarities. They both have one-dimensional chainlike structures which probably are the result of the large Ph4P+ cations. They both contained unique thioarsenate ligands, [A5387]5‘ and [AS489]5', formed by condensation reactions of the pyramidal [A583]3' units. The main structural differences between the two compounds arise from the metal coordination. The In3+ ions, in [InAS3S7]2‘, adopt trigonal bypyramid geometry while the Sn4+ ions, in [SnAS489]2', take an octahedral environment. This imply that metal coordination preference may actually dictate the formation of the [ASxSyIn' species. (Me4N)2Rb[BiA56812) was synthesized by heating BiCl3 with Rb3A583 and Me4NCl in H2O at 120 °C for one week. The anionic [BiA55812],,3"' possesses a two-dimensional layered structure with trigonal symmetry consisting of octahedral Bi3+ ions and [A5385]3' cyclic units formed by three corner-sharing trigonal pyramidal [ASS3]3’ units; see Figure 2-5. The [A5386]3' units were first observed as a discrete molecule in (enH2)3(A53S(,)2,20 The [A5385]3' fragment in (Me4N)2Rb[BiA56812] is located on a 3-fold axis with three As atoms and three 8 atoms forming a six-membered ring in a chair conformation. In [A5386]3‘ the As-S bonds are separated into two types. The intra-ring As—S distance, at 2.312(2) A, is significantly longer than the other As-S distance, at 2.189(3) A. Similar distances were observed in (A5385)3',20 Selected bond distances and angles are 70 Table 212. Selected Distances (A) in (Me4N)2Rb[BiA55812] with Standard Deviations in Parentheses.a Bi - Sl 2.830(2) As - 52 2.296(3) Rb 4 52 3.461(2) N - C1 1.49(1) As - 51 2.190(3) N - C2 1.49(1) As - 52 2.312(2) Table 2-13. Selected Angles (Deg) in (Me4N)2Rb[BiA55812] with Standard Deviations in Parentheses.a Sl - Bi - Sl 88.92(6) 81 - As — 82 99.7(1) 81 - Bi - 81 180.00 82 - As - Sl 91.96(7) Sl - Bi - 81 91.08(6) Bi - Sl - As 102.30(7) 82 - Rb - 82 ll8.75(5) Bi - Sl - A5 92.47(6) 82-Rb-82 ll8.75(5) Cl-N-C2 111.1(6) 81 - As - Sl 89.33(9) ' C2 - N - C2 107.8(6) Sl - As - 82 97.34(8) 2‘The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {Zn(ln - l)2/n(n-l)}1/2, where In is the length (or angle) of the nth bond, l the mean length (or angle), and n the number of bonds. 71 Figure 2-5. Structure and labeling scheme Of one [BiAsGSu]n3n- layer. 72 s ‘ O O D D '.'.F' O O" l On I! ”\\~ Figure 2-6. Packing diagram of (Me4N) 2Rb[BiA568 121 73 given in Tables 2-12 and 2-13. The Bi3+ ion is in a nearly perfect octahedral geometry. The overall organization of the Bi3+ and the [A5385l3' ions is CdCl2-type with the cations in the Cd“ and the anions in the Cl' sites, respectively. The Bi-S bond distance, at 2.830(2) A, is in the normal range for the Bi-S bonds.21 The Me4N+ and the Rb+ cations are located between the [BiA55812],.3"' layers, see Figure 2-6, which are spaced 9.445 A apart The Rb+ and [A8386]3' ions share a common C3 axis so that each Rb+ ion is coordinated to six bridging 8 atoms from two [A5385]3' units, one above and one below, in a trigonal antiprismatic fashion. The Rb---S distance is 3.458(2) A. We noticed that the same A538 3 six membered rings previously seen in the Rb2A53813,22 which is also a Rb salt, were also found in (Me4N)2Rb[BiA5(,812]. It is possible that the Rb cation is just the right size to coordinate to six sulfur atoms from two [A5386]3' units and that this structure type may not be stable for either the smaller K cation or the larger Cs cation. Hence, the Rb here may act both as cation and as structure directing template. One can then speculate that the larger AS484 eight membered rings might possibly coordinate with the larger Cs as the cation as seen in C52A53813.23 The larger space generated by the Cs cations may also need larger organic cations, such as Et4N+, to be filled. The lone electron pair on 313* is stereochemically inactive and apparently is delocalized around the Bi nucleus. This is common for octahedral Bi3+ sites and has been found earlier in other Bi-S compounds such as KBi82.19 3.2 Physicochemical studies 74 In the far-IR region all complexes reported here exhibit spectral absorptions due to As-S and M-8 stretching vibrations as shown in Figure 2-7. Observed absorption frequencies of all the complexes are given in table 2-14. Table 2-14. Frequencies (cm-1) of Raman and Infrared Spectral Absorptions of (Ph4P)2[InAS3S7](I), (Ph4P)2[SnAS489](II), and (Mc4N)2Rb[BiA55812](III). Compounds Infrared Raman (Ph4P)2[InAS3S7] 400(5), 373(5, sh) 395(5). 375(m), 352(m) 346(m), 284(5, br) 329(w), 301(m), 253(m) 225(m), 205(m) 186(m), 154(w) (Ph4P)2[SnAS489] 387(m), 374(m) 409(w), 387(m), 380(m) 340(m, sh), 288(5) 341(5), 292(m), 256(m) 250(m. br). 211(m) 199(m). 155(w) 198(m) (Me4N)2Rb[BiAs6512] 389(5), 370(w) 354(m), 302(5. br) 186(5, br) 154(w) T\ 8: strong, m; medium, w: weak, sh: Shoulder. In the Par-IR spectra, see Figure 2-7, of (Ph4P)2[InAS3S7], (Ph4P)2[SnAS489], and (Me4N)2Rb[BiA56812], the peaks in the region of 250‘400 cm'1 could be attributed to As-S vibration modes. Similar a ' - ssrgnments have been made In the far-IR spectra of other known '75 (A) J (B) X TWITTANCE (C) 560 its 362 316 315 260 295 212’ 178 unveuuneea his Figure 2-7. Far-1R spectra Of (A) (Ph4P)2[InAS3S7], (B) (Ph4P)2[SnA54891 and (C) (M84N)2Rb[BiA56512] 76 thioarsenate complexes.24 Furthermore, the additional peaks in the IR spectra at 225 cm'1 and 205 cm'1 for (Ph4P)2[InAS3S7], at 211 cm' 1 and 198 cm'1 for (Ph4P)2[SnAS489], and at 186 cm'1 for (Me4N)2Rb[BiA55812] may be possible candidates of an M-S stretching vibration. Assigning the observed IR spectra of these compounds is difficult because As-S and M-8 stretching frequencies fall in the same low frequency region of 150-350 cm'l, The Raman spectra of (I) and (II) were also recorded while the spectrum of (III) was not due to a large diffuse reflectance which obscured the area from 2000 cm'1 to 200 cmrl. There are numerous peaks between 150 and 450 cm'l, see Table 2-13, just as in the far- IR Spectra. The peaks in the range from 250 - 400 cm'1 could be due to As-S vibration modes while the lower energy peaks, at 186 cm‘1 and 154 cm'1 for (I) and 199 cm‘1 and 155 cm'1 for (11), might be due to the M-8 vibration mode. Thermal Gravimetric Analysis (TGA) results for all compounds are summarized in Table 2-15 and shown in Figures 2-8 and 2-9. Table 2-15. TGA data for (Ph4P)2[InAS3S7](I), (Ph4P)2[SnAS489](II), and (Me4N)2Rb[BiAS5812](III). Compound Temp. range (°C) Weight loss (%) (Ph4P)2[InAS3S7] 224 - 600 78.3 (Ph4P)2[SnAS489] 290 - 600 67.8 (Me4N)2Rb[BiA568121 120 - 750 65.2 h 77 l 20 F l l A) 100 - ( __ g 80 .. __ 3 60 - __ 40- _ 20 , I I :4, 0 200 400 600 800 Temp. ('C) J I 1 ‘ 100 -’ (B) _ 80 - _ é . - b 3 60 - b 40- _ 20 , I . ° 200 400 600 goo Temp. (‘C) Figure 2-8. TGA diagrams of (A) (Ph4P)2[InAS3S7] and (B) (Ph4P)2[SnA54391 78 110 1 1 1 100‘ - 90‘ — 80‘ - 70‘ - 60‘ - VVGK) 40- .- 30 I I - I 0 200 400 ' 600 800 TaanTD Figure 2-9. TGA diagram of (Me4N) 2Rb[BiA568121 79 (Ph4P)2[InAS3S7] shows a one step weight loss of 78.3 % in the temperature range of 224-600 °C probably as Ph3PS, other organic Species and various AsxSy. The X-ray powder diffraction analysis of the final residue indicates the presence of InA5284 and other phases that can not be identified. (Ph4P)2[SnAS489] also shows a clean one step weight loss of 67.8 % in the temperature range of 290-600 °C. The final product was proved to be SnS(Herzenbergite) by X-ray powder diffraction. For (Me4N)2Rb[BiA55812], a weight 1055, 65.2 %, occurred gradually over the temperature range 120 to 750 °C. The final residue appears by SEM/EDS analysis to be Rbo,3Bi283. From the TGA results, compounds (I) and (II) do show some thermal stability. There is no weight 1055 up to 200 and 290 °C for (I) and (II) respectively. The thermal behavior of (I) and (II) were further studied by DTA (differential thermal analysis). We did not observed any melting before the decomposition temperature. Visual inspection of the “product, under the microscope, confirmed that no melting occurred. Slight discoloration of the crystals indicated the compounds were starting to decompose. The optical properties of (Ph4P)2[InAS3S7], (Ph4P)2[SnAS489], and (Me4N)2Rb[BiA56812] were assessed by studying the UV-visible- near IR spectra of the material. The spectra confirm that these compounds are wide band-gap semiconductors. The optical absorption spectra of (Ph4P)2[InAS3S7](I) and (Ph4P)2[SnAS489](II), shown in Figure 2-10, exhibit an intense, steep absorption edge for both compounds, revealing optical bandgaps of 3.1 eV and 2.8 eV 80 12 ' ‘ 1 J 1 1 10- (A) _ (Ph4P) zllnAs 35 a/S absorption Coeff. (arb. units) at 1 4" Eg=3.lev — 2- .. 0 7‘1 T I I I I 0 1 2 3 4 5 6 7 EnergyleV) 7t; 2 1 l l I 1 l E (B) .15 1.6- _ 3. § 1.2- _ C: ' (Ph4P)2[SnAS489] .9. 0.8... Eg-2.8 eV é — .8 «I 0.4“ _ Q ‘3 0-1 I I I I I 0 1 2 3 4 5 6 7 EnergyleV) Figure 2-10. Optical absorption spectra of (A) (Ph4P)2[InAS3S7], and (B) (Ph4P)2[SnAS4S9l 81 A 0.6 1 1 l I I 1 “5 =3 0.5- .. i r: 0.4- _ 8 0.3- _ g (Me4N)sz[BiAs 6512) ‘5. 0.2- _ § Egsl.leV '8 0.1- L S O I I I I l l O l 2 3 4 5 5 7 Energy(eV) Figure 2-1 1. Optical absorption spectrum of (Me4N) 2Rb[BiAS(,S121 82 respectively. (Me4N)2Rb[BiA55812](III) absorbs light strongly throughout the visible region with a Amax of 520 nm; see Figure 2- 11. Its electronic spectrum reveals an optical bandgap of 1.1 eV, which is within the range appropriate for efficient solar energy collection and suggests possible photoconductivity in this material. The absorption is probably due to a charge-transfer transition from a primarily sulfur-based valence band to a mainly metal-based conduction band. Remarkably, despite the fact that the arsenic/sulfide source in all reactions was [AsS3]3', we do not observe this discrete unit in the new structures. Rather, in [InA5387]2', [SnA5489]2‘, and [BiA55812]3', we find respectively the unusual chainlike [A5387]5' [A5489]5‘, and cyclic [A5385]3’ fragments which are formed from corner-sharing [A583]3’ units. These units result from condensation reactions in water in which several equilibria of the type shown in eqs. 2.1-2.4 must exist. A5833' + A583" 2 [As25514' + 52' (54.2.1) [As,s,]" + A583" = [As,s,]5' + 51' (Eq.2.2) [A538715' + Ass," 2: [As,s,]" + 52' (54.2.3) [A5387ls' z_——_-— [As,s,]3' + 52' (Eq.2.4) These condensation reactions parallel those found in the condensation of SiO44' and PO43' units.1 Therefore, as in these 83 systems, one would expect that a variety of [AsxSyln' species might be possible. It must be mentioned that the degree and extent of these equilibria are probably influenced by the presence of the metal ions in solution. In addition, however, these condensation reactions were probably facilitated by the protonation of the terminal sulfur atoms, see eqs 2-5 and 2-6 - s 43. _ s .2- AL + 11+ if : AIS (eq 2-5) _5/ \SJ _5/ \SIII . s -2- 2 AL e r‘ [A5285]"+ H28 (eq 2-6) _./ \.., In conclusion, the successful hydrothermal synthesis of (Ph4P)2[InAS3S7], (Ph4P)2[SnAS489], and (Me4N)2Rb[BiA56812] by using A5833' as starting material opens exciting possibilities for the further exploration of metal/arsenic/sulfide and related systems. Key to this is the complex condensation equilibria which exist among various [AsxSyln' species in the reaction medium. A5 in other labile systems, the size of the counter-cations is expected to influence the structural dimensionalities of the covalent framework.25 From comparing the structure of (Ph4P)2[InAS3S7](I) and (Ph4P)2[SnAS489](II), we noticed that the metal coordination preference also play a major role in the formation of different [AsxSyln' species. Different coordination geometry may dictate the formation of different [AsxSyV' species. It is interesting, for example, that the one-dimensional chain structure 84 of [InAS3S7]2' was isolated with the large Ph4P+ ion, while the two- dimensional framework of [BiA56812]3' formed with the small Me4N+ and Rb+ cations. Although the controlled synthesis of specific [AsxSy]"' ligands may be challenging, the above equilibria should undOubtedly be exploited for the synthesis of new thioarsenates and related compounds. 85 REFERENCES (a) Liebau, F. Structural Chemistry of Silicates ; Springer: New York, 1985. (b) Day, V. W.; Klemperer, W. G.; Mainz, V. V.; Millar, D. M. J. Am. Chem. Soc. 1985, 107, 8262-8264. (c) Cotton, F. A.; Wilkinson, G. Advanced Inorganic Chemistry ;John Wiley & Sons: New York, 1988, pp 421-430. (a) Chopin, F.; Turrell, G. J. Mol. Struct. 1969, 3, 57-65. (b) Krebs, B.; Diercks, H. Acta Crystallogr.19‘75, A31, 566-585. (c) Krebs, B. Angew. Chem., Int. Ed. Engl. 1983, 22, 113-134 and references cited therein. (a) Krebs, B.; Pohl, 8.; Schiwy, W. Angew. Chem., Int. Ed. Engl. 1970, 9, 897-898. (b) Krebs, B.; Pohl, 8.; Schiwy, W. Z. Anorg. Allg. Chem. '1972, 393, 241-252. (c) Pohl, 8.; Schiwy, W.; Weinstock, B.; Krebs. B. Z. Naturforsch. 1973,828, 565-569. (d) Pohl, 8.; Krebs. B. Z. Anorg. Allg. Chem. 1976,424, 265-272. (a) Sommer, V. H.; Hoppe, R. Z. Anorg. Allg. Chem. 1977, 430, 199-210. (D) Sinning, H.; Muller, U. Z. Anorg. Allg. Chem. 1989, 568, 49-54. (c) Sinning, H.; Muller, U. Z. Anorg. Allg. Chem. 1988, 564, 37-45. (d) Siewert, B.; Muller, U. Z. Anorg. Allg. Chem. 1992, 609, 82-88. (e) Siewert, B.; Muller, U. Z. Anorg. Allg. Chem. 1991,595, 211-215. Sheldrick, W. 8.; Kaub, J. Z. Naturforsch. 1985, 403, 1130-1133. 10. 11. 12. l3. 14. 15. 16. 8 6 Porter, E. J.; Sheldrick, G. M. J. Chem. Soc. Dalton. Trans. 1971, 3130-3134. Sheldrick, W. 8.; Kaub, J. Z. Naturforsch. 1985, 40b, 19-21. O’Neal, 8. C.; Penington, W. T.; Kolis, T. W. Inorg. Chem. 1992, 31. 888-894. Zank, G. A.; Rauchfuss, T. B.; Wilson, 8. R. J. Am. Chem. Soc. 1984, 106, 7621-7623. O’Neal, 8. C.; Penington. W. T.; Kolis, T. W. J. Am. Chem. Soc. 1991, 113, 710-712. Chou, J.-H.; Kanatzidis. M. G. Unpublished results. (a) Wendlandt, W. W.; Hecht, H. G. "Reflectance Spectroscopy", Interscience Publishers, 1966. (b) Kotiim, G. "Reflectance Spectroscopy", springer Verlag, New York, 1969. (c) Tandon, S. P.; Gupta, J. P. Phys. Stat. Sol. 1970, 38, 363-367. Sheldrick, G. M. In Crystallographic Computing 3; Sheldrick, G. M.; Kruger, C.; Goddard, R., Eds.; Oxford University Press: Oxford, U.K., 1985; pp 175-189. TEXSAN: Single Crystal Structure Analysis Package, Version 5.0, Molecular Snucture Corp., Woodland, TX. Walker, N.; Stuart, D. Acta Crystallogr. 1983,39A, 158-166. CERIUS: Single Crystal Structure Analysis Software, Version 5.0, Molecular Simulations Inc. Cambridge, UK. 17. 18. 19. 20. 21. 22. 23. 24. 25. 87 Dhingra, 8.; Kanatzidis, M. G. Inorg. Chem. 1989, 28, 2024- 2026. Dhingra, S. 8.; Kanatzidis, M. G. Inorg. Chem. 1993, 32, 3300- 3305. Schiwy, W.; Blutau, C.; Gathje, D.; Krebs. B. Z. Anorg. Allg. Chem. 1975, 412, 1-10. (a) en = ethylenediamine. (b) Sheldrick, W. 8.; Kaub, J. Z. Naturforsch. 1985, 408 19-21. Schmitz, D.; Bronger, W. Z. Naturforsch. 1974, 298, 438-439. Sheldrick, W.; Kaub, J. Z. Naturforsch. 1985, 40b, 1130-1133. Sheldrick, W.; Kaub, J. Z. Naturforsch. 1985,40b, 571-573. Peresh, E. Y.; Golovei, M. 1.; Berul, S. I. lzv. Akad. Nauk SSR Neorg. Mater. 1971, 7, 27-30. (a) Huang, S.-P.; Kanatzidis, M. G. Inorg. Chem. 1991,30, 1455- 1466. (b) Kim, K.-W.; Kanatzidis. M. G. J. Am. Chem. Soc. 1992, 114, 4878-4883. 88 CHAPTER 3 HYDROTHERMAL SYNTHESIS OF M/AsxSy (M = Ni“, Mo5+) COMPOUNDS. SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (Ph4P)2[Ni2AS4581(I), and (Me4lelM0202A8257101) 89 ABSTRACT (Ph4P)2[Ni2AS483], and (Me4N)2[M0202A5287] were synthesized by hydrothermal reactions of NiCl2/K3ASS3/Ph4PBr and MoO3/K3AsS3/Me4NCl in a 1:3:4, and 1:2:4 molar ratio, respectively. The (Ph4P)2[Ni2A5483] compound crystallizes in the triclinic space group P-1(No. 2) with a = 10.613(3) A, b = 13.230(2) A, c = 9.617(2) A, or = 9353(2), B = 96.69(2)°, y = 7159(2), v = 1272(1) A3, 2 = 2. The [Ni2A5483]n2"' macroanion is a one-dimensional chain consisting of alternating square planar N12+ ions and [A5483]4' units, the latter formed by corner-sharing [AsS3]3° units. The (Me4N)2[Mon2A5287] compound crystallizes in the orthorombic space group Pbca(No. 61) with a = 18.176(4) A, b = 17.010(2) A, c = l6.556(7) A, v = 5118(4) A3,Z = 4. The [M0202AS2S7],,2"' macroanion also has a one- dimensional chain-like structure and contains M020282 fragments linked by [A5285]4' units into a one-dimensional chain. The solid state optical and vibrational spectra of these compounds are reported. 90 1. Introduction The incorporation of main group thiometallates in solid state extended frameworks in combination with transition and other main group metals promises to yield new solids with properties varying from semiconductivity to microporosity. The latter property could be achieved with large organic templates around which an open structure can assemble. At this stage use of organic counterions such as Ph4P+ and R4N+ seems appropriate. Although there is substantial precedent for hydrothermal (or solvothermal) synthesis of solids with thio- and chalcogeno- anions in the latticel- 2. 3 , the use of the basic [A583]3' anion has been limited. Recently, we have shown that hydrothermal exploratory investigations of the systems R4E+ (E = P, R = Ph; E=N, R = alkyl)/Mn+/[ASS3]3‘, (where M is a main group element) can lead to novel polymeric materials containing unusual thioarsenate polyanions as building blocks. These compounds include (Ph4P)2[InAS3S7] and (Me4N)2Rb[BiA55S12].4 The former has a one-dimensional chain structure and contains unusual chain-like [A5387]5’ units while the latter is a mixed salt with a two- dimensional layered structure featuring cyclic [A5385]3' units. In these compounds the [A583]3' anion shows a facile condensation ability that results in higher nuclearity [AsxSyP' units which are found coordinated to the metal cations. These reactions (see chapter 2) are probably catalyzed by protonation of the terminal sulfide groups. Kolis et al. have also demonstrated that superheated ethylenediamine is also a suitable solvent for synthesis of new metal/AsxSy compounds. They have reported two new quaternary 91 phases, KCu2AsS3 and KCu4AsS4, formed by reacting KA582 with Cu powder in superheated ethylenediamine.5 By using a strong base, however, as the reaction solvent, the condensation reactions mentioned above, between the [A583]3‘ units are not favored and the resulting compounds tend to contain only the most basic thioarsenic anion, [A583]3', as the building block. In order to investigate further this tendency for condensation, and being aware of the wealth of different structure types exhibited by other condensable units (e. g. [SiO4]4' 5, [PO4]3' 7), we explored the hydrothermal behavior of the R4E+/Mn+/[ASS3]3' (E = P, R = Ph; E = N, R = Me, M = transition metal) system. There are several examples of early transition metal complexes which contain discrete thioarsenate ligands. The very first complex, Cp‘3Ti2O(ASS3) (Cp' = 115-CH3C5H4) synthesized by Rauchfuss and co-workers,8 demonstrated that the thioarsenate anion, [A583]3', could be used as ligands toward transition metals. They also reported a Mo compound, [M0202A84S]4]2', which contains the highly unusual [AS4812]4' ligand and further indicates the great potential new chemistry that [AsxSyP' can provide. Here we report the successful synthesis of two new polymeric compounds by using transition metals. The two novel low- dimensional compounds, (Ph4P)2[NizAS483], and (Me4N)2[M0202A5287] also feature higher order [ASxSy]n- units derived from the condensation of the [A583]3' anion, which are different from those found in (Ph4P)2[InAS3S7] and (Me4N)2Rb[BiAS6812]. These 92 compounds are new members of a rare group of crystalline inorganic solid state compounds that contain organic cations.9'14 2. Experimental Section 2.1 Reagents Chemicals. Chemicals in this work, other than solvents, were used as obtained. NiClz, 98% purity, purity, M003, 99% purity, tetraphenylphosphonium bromide (Ph4PBr), 98% purity, tetramethylammonium chloride, (Me4NCl), 99% purity, Aldrich Chemical Company, Inc., Milwaukee, WI. A3AsS3 (A = K, Rb, Cs) were synthesized by using stoichiometric amounts of alkali metal, arsenic sulfide (A5283), and sulfur in liquid ammonia. The reaction gives a yellow brown powder upon evaporation of ammonia. 2.2 Syntheses All syntheses were carried out under dry nitrogen atmosphere in a Vacuum Atmosphere Dri-Lab glovebox except were specifically mentioned. (Ph4P)2[N12A54Ss]: A mixture of 0.025g (0.2 mmol) NiCl2, 0.172g (0.6 mmol) K3A583 and 0.4l9g (1 mmol) Ph4PBr was sealed in thick wall Pyrex tube (.. 4mL) under vacuum with 0.3 mL of water. The reaction was carried out at 110 °C for one week. The product I was isolated by washing off excess starting material and KCl with H20, methanol, and ether to give 0.105g (76% yield) of dark brown plate-like crystals. SEM/EDS analysis on these crystals showed the P:Ni:As:8 ratio as 2:1:l.8:9.l. 93 (Me4N)2[M0202Aszs7]: The reaction mixture of 0.02g (0.2 mmol) M003, 0.057g (0.4 mmol) K3AsS3 and 0.13g (0.12 mmol) Me4NCl was prepared as above. The mixture was heated to 110 °C for 3 days. Large yellow chunky crystals were isolated in H20 and washed with methanol and ether. (Yield = 88% based on Mo) SEM/EDS analysis on these crystals showed the Mo:As:S ratio as l.1:l:6.2. 2.3. Physical Measurements The instruments and experimental setups for Infrared measurements, optical diffuse reflectance measurements, thermal analysis, and quantitative microprobe analysis on SEM/EDS are the same as those in Chapter 2 . 2.4 X-ray crystallography (Ph4P)2[Ni'2AS483]: A well shaped dark brown crystal with dimensions of 0.65 x 0.55 x 0.25 mm was mounted on a glass fiber. Single-crystal X-ray diffraction data were collected at room temperature on a Rigaku AFC6 diffractometer and the 00-20 scan technique was used. A total of 2878 independent reflections were collected. All the ~ nonhydrogen and non-carbon atoms were refined anisotropically. All hydrogen atom positions were calculated and fixed without further refinement. (Me4N)‘2[M0202Aszs7]: A well shaped orange crystal with dimensions of 0.45 x 0.35 x 0.5 mm was mounted on a glass fiber. Single-crystal X-ray diffraction data were collected at room 94 temperature on a Rigaku AFC6 diffractometer and the 03-20 scan technique was used. A total of 3769 independent reflections were collected. All the nonhydrogen atoms except carbon were refined anisotropically. All hydrogen atom positions were calculated and fixed without further refinement. During the structure refinement we found that a carbon atom (C5) in one of the tetramethylammonium cations was slightly disordered. The occupancy of the two positions C5 and C5' were refined to be about 50% each. The crystals did not showed any significant decay as judged by three check reflections measured every 150 reflections throughout the data collection. The space group was determined by systematic absences and intensity statistics. All the structures were solved by direct methods (SHELXS-86)15 and refined with the TEXSAN15 software package. An empirical absorption correction (DIFABSI7) was applied to the isotropically refined data. All non- hydrogen atoms except nitrogen and carbon were refined anisotropically. All calculations were performed on a VAXstation 3100 Model 76 computer. Table 3-1 summarizes the crystallographic data and details of the structure solution and refinement. The final atomic coordinates with their estimated standard deviations (esd's) are given in Tables 3-2 and 3-3. 95 Table 3-1. Summary of Crystallographic Data and Structural Analysis for (Ph4P)2[Ni2AS4S3](I), and (Me4N)2[M0202AS2S7](II). I 11 Formula C48H40P2NiAS483 C3H24N2M0202AS2S7 F. w. 1351.1 745.72 a, A 10.612(4) 18.176(4) b, A 13.230(2) 17.010(2) c, A 9.617(2) 16.556(7) a, deg. 93.53(1) 90.00 13, deg. 96.69(2) 90.00 7, deg. 71.59(2) 90.00 z,v,A3 2, 1272(1) 4, 5118(4) Space Group P—I (No. 2) Pbca(No. 61) color, habit Dcalc. g/cm3 Radiation 1.1, cm‘1 26m“, deg. . Absorption Correction Transmission Factors Index ranges No. of Data coll. Unique reflections Data Used (F02 > 30(F02» No. of Variables Final Ra/wa, % dark brown, plate l.69 Mo Kat 73.76 45.0 v scan 0.73-1.13 OshglLJ4gkg 14, -10 _<_l_<_10 2989 2878 1984 286 3.7/4.3 orange yellow, plate 1.94 Mo Kat 40.75 45.0 \V scan 0.96-1.02 OsthQOsngL 051520 3859 3769 1874 196 4.9/6.4 11 R= Z(lFo|-|Fcl)/2|Fol, b Rw={Zw(|Fol-|Fc|)2/2w|Fo|2}1’2 96 Table 3-2. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[Ni2AS483](I). atom X Y Z BmL(A2) Ni 0.50000 0.50000 0.00000 3.4(1) Asl 0.7376(1) 0.3167l(7) 0.1454(1) 4.44(6) As2 0.8697(1) 0.46009(7) -0.0314(1) 4.00(6) Sl 1.0617(3) 0.4380(2) -0.1377(2) 5.1(2) $2 0.9398(2) 0.2983(2) 0.0646(2) 4.2(1) S3 0.5966(2) 0.3278(2) -0.0452(3) 5.0(1) S4 0.6608(2) 0.4927(2) 0.1695(2) 4.6(1) P1 1.1891(2) 0.1744(2) 0.4976(2) 3.4(1) C1 1.1655(9) 0.0844(6) 0.3592(8) 3.5(1) CZ 1.041(1) 0.0827(6) 0.3073(8) 4.0(5) C3 1.026(1) 0.0070(8) 0.207(1) 5.2(7) C4 1.137(1) -0.0688(8) 0.159(1) 6.1(8) C5 1.261(1) -0.0669(7) 0.209(1) 6.0(1) C6 1.277(1) 0.0106(7) 0.308(1) 5.0(1) C7 1.2995(8) 0.2410(6) 0.449(1) 4.1(5) C8 1.291(1) 0.2701(7) 0.310(1) 5.2(6) C9 1.378(1) 0.3228(8) 0.276(1) 6.0(7) C10 1.466(1) 0.3455(8) 0.377(2) 6.7(8) C11 1.475(1) 0.3176(9) 0.513(1) 6.9(8) C12 1.392(1) 0.2646(6) 0.547(1) 5.6(7) C13 1.0314(8) 0.2672(6) 0.5286(8) 3.1(5) 0.9817(9) 0.3635(6) 0.4621(8) 3.6(5) C14 97 C15 0.858(1) 0.4329(6) 0.486(1) 4.5(6) C16 0.7849(9) 0.4058(7) 0.579(1) 4.7(6) C17 0.833(1) 0.3100(8) 0.6469(9) 4.7(6) C18 0.9561(9) 0.2419(6) 0.6209(9) 4.2(5) C19 1.2574(9) 0.0998(6) 0.6525(9) 4.2(5) C20 1.258(1) 0.1549(7) 0.783(1) 5.8(6) C21 1.310(1) 0.091(1) 0.905(1) 7.4(8) C22 1.362(1) -0.010(1) 0.897(1) 7.5(9) C23 1.360(1) -0.0638(8) 0.74491) 6.6(7) C24 1.308(1) -0.0106(7) 0.651(1) 4.9(6) 1‘ B¢q=(4/3)[a2311 + b2B22 +c2B33 + ab(cosy)812 + ac(cosB)Bl3 + bc(cosa)Bz3] Table 3-3. Selected Atomic Coordinates and Estimated Standard 98 Deviations (esd's) of (Me4N)2[M0202AS287](II). atom X Y Z Bill: (A2) M01 0.6397(1) 0.7862(1) 0.1285(1) 1.85(7) M02 0.6021(1) 0.9237(1) 0.2174(1) 1.83(7) Asl 0.6469(1) 0.6090(1) 0.051691) 2.5(1) A82 0.5127(1) 1.0394(1) 0.3516(1) 2.6(1) Sl 0.4868(3) 0.9961(3) 0.2268(3) 3.0(3) 82 0.5847(3) 0.9331(3) 0.3632(3) 2.4(2) S3 0.6654(3) 0.8132(3) 0.2640(3) 2.4(2) S4 0.5425(3) 0.8728(3) 0.1040(3) 2.3(2) SS 0.5672(3) 0.7071(3) 0.0345(3) 2.7(3) S6 0.6650(3) 0.6543(3) 0.1768(3) 2.6(3) S7 0.5830(3) 0.4969(3) 0.0728(3) 2.6(3) ()1 0.7135(7) 0.8096(7) 0.0719(7) 2.5(6) 02 0.6652(7) 0.9920(7) 0.1887(8) 2.6(7) N1 0.299(1) 0.045(1) 0.094(1) 2.5(8) N2 0.594(1) 0.235(1) 0.165(1) 4(1) C1 0.354(1) 0.112(1) 0.107(1) 3(1) C2 0.292(1) -0.003(1) 0.169(1) 4(1) C3 0.229(1) 0.074(2) 0.070(2) 8(2) C4 0.330(2) -0.007(2) 0.028(2) 6(2) C5 0.511(3) 0.219(3) 0.164(3) 5(1) 99 C5' 0.515(2) 0.231(2) 0.196(2) 1.5(9) C6 0.611(2) 0.311(3) 0.134(3) 3(1) C6' 0.620(3) 0.317(3) 0.196(4) 6(1) C7 0.612(2) 0.188(3) 0.101(3) 12(1) C8 0.633(3) 0.207(2) 0.235(3) 13(1) 3 B¢q=(4/3)[a2B11 + b2B22 +c2B33 + ab(cosy)B12 + ac(cosB)B13 + bc(cosa)B23] 100 The compounds were examined by X-ray powder diffraction to determine phase purity and for identification. Accurate db“ spacings (A) were obtained from the powder patterns recorded on a calibrated (with FeOCl as internal standard) Phillips XRG-3000 computer-controlled powder diffractometer with graphite- monochromated Cu Kat radiation operating at 35 kV and 35 mA. The data were collected at a rate of 0.12°/min. Based on the atomic coordinates from X-ray single crystal diffraction study, X-ray powder patterns for all compounds were calculated, by the software package CERIUS.18 Calculated and observed X-ray powder patterns that show d-spacings and intensities of strong hkl reflections are complied in Tables 3-4 to 3-5. 101 Table 3—4. Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[NiAS488](I)- h k l dmd.) deg; (A) I/Imobs, %) o 1 0 12.54 12.5 100 1 o 1 10.00 9.98 11 o o 1 9.55 9.53 35 o 1 -1 7.70 7.68 22 o 1 1 7.50 7.50 70 1 1 -1 7.11 7.10 20 1 1 6.33 6.32 11 1 2 o 6.26 6.25 27 1 -1 -1 5.72 5.71 11 1 -1 1 5.42 5.40 41 o 2 1 5.18 5.18 29 o o 2 4.77 475 11 1 -2 o 4.69 4.68 22 o 1 2 4.42 4.41 65 2 2 -1 1 o 2 4.14 4.14 12 3 2 -1 3.35 o 3 -2 3.19 3.18 11 2 2 2 3.16 3.16 12 3 2 -2 2.953 2.951 14 L3 2 2.86 102 Table 3-5. Calculated and Observed X-ray Powder Diffraction Pattern of (Me4N)2[M0202AS287](II). h k 1 4121(4) a124,, (A) I/Immbs, %) 1 1 1 9.93 9.91 25 2 o o 9.09 9.08 16 o o 2 8.27 8.27 14 2 1 o 8.02 8.01 100 1 o 2 7.53 7.53 47 2 1 1 7.21 7.20 24 1 1 2 6.89 6.88 15 1 2 2 5.63 5.63 31 3 o 2 4.89 4.88 21 2 3 o 4.81 4.80 13 3 1 2 4.70 4.70 10 2 1 3 4.54 4.55 30 4 o o 3 3 1 4.01 4.00 9 4 2 o 4 2 1 3.89 3 5 1 2.919 2.917 9 2 7 1 2.324 2.323 12 1 1 7 103 3. Results and discussion 3.1 Syntheses and Description of structures (Ph4P)2[NiA84Sg] was prepared by heating NiClz with K3AsS3 and Ph4PBr in H20 at 120 °C. It is well known in metal polychalcogenide chemistry that different cations can stabilize different structure types.19 Since, conceptually, thioarsenic anions are similar to polysulfide ligands, we did try other cations, such as tetraalkyl ammonium, in reactions with similar reactant ratios hoping that different compounds could be isolated. We noticed that in these reactions, however, the reaction mixture immediately turned into a black precipitate of Nin as soon as the water was added. No other product was observed after heating was completed. The same phenomena occured with the Ph4PBr reaction, however, prolonged heating resulted the formation of dark brown plates of (Ph4P)2[NiA84S3] as the major product along with small amount (5%) of black NiS precipitate. (Ph4P)2[NiAS483] does not dissolve in common organic solvents. The structure was determined by X-ray single-crystal diffraction analysis. [NiAs483ln2'P has an unusual one-dimensional polymeric structure composed of Ni“ ions and [AS4S3]4' units formed by comer—sharing pyramidal [AsS3]3‘ units; see Figure 3-1. The [N12A8488]n2"' chains are parallel to the crystallographic a-axis and well separated by Ph4P+ cations, see Figure 3-2. The Ni2+ resides on an inversion center with Ni—S distance range from 2.202(2) to 2.222(2) A. The unique feature of this compound is the [As483l4' ligand which can derive from the 104 condensation of four [AsS3J3' units. Remarkably, the [A8483I4' unit contains a four membered AS282 ring with trans connections to the other AsS3 units. A similar four membered ring in a cis connection, [AS5812]5', has recently been found in the sulfosalt PleAS386.20 The [AS488]4' units can also be viewed as the intramolecular condensation product of the [AS439]6' units from [SnA84S9]2-, see scheme 1. The [AS483]4' represents a new thioarsenate anion. 6 - 4 2. A s/ Als\S/\:\S s/SS\1 S S/|\S/?\S S A__",/5 s S\A|s/S\Als/S [A845916- [A8433]‘. Scheme 1 The N12+ ion is in an almost perfect square planar environment with bond angles of S3-Ni-S3 = 180.00, S3-Ni-S4 = 8859(9) S3-Ni-S4 = 91.4l(9), and S4-Ni-S4 = 180.00. The average As-S distance and the average S-As-S angles are well within the normal range found in other arsenic sulfide compounds.21 The average Ni-S bonding distance is normal at 2.212(2) A. Selected bond distances and angles are contained in Tables 3-6 and 3-7. We can rationalize the formation of the [AS483]4' unit simply by the coordination number of the metal ion. The coordination preference of the Ni centers in Ni/S compounds is square planar, as in our compound, with CN of four. A chainlike ligand connecting two Ni center together would need two available terminal sites on either end of the chain. The [AS439l6' unit, however, has three terminal S atoms on either side of the chain, and in order to get rid of the two extra S atoms the [AS489]6' anion 105 Table 3-6. Selected Distances (A) in (Ph4P)2[Ni2AS4S3] with Standard Deviations in Parentheses.a Ni - S3 2.222(2) Ni - S4 2.202(2) Asl - 82 2.303(3) Asl - S3 2.208(3) A81 - S4 2.218(2) A82 - Sl 2.314(3) A82 - S1 2.250(2L A82 - 82 2.250(2) Table 3-7. Selected Angles (Deg) in (Ph4P)2[Ni2AS483] with Standard Deviations in Parentheses.a S3 - Ni - S3 180.00 83 - Ni - S4 88.59(9) S3 - Ni - S4 . 9141(9) S4 — Ni - 84 180.00 S2 - Asl - 83 104.8(1) 82 - Asl - S4 99.8l(9) S3 - Asl - S4 88.51(9) Sl - As2 - Sl 89.53(9) 81 - As2 - 82 95.48(9) Sl - As2 - S2 102.5(1) A82 - Sl - A82 90.47(9) Asl - 82 - A82 93.99(9) A81 - 83 - Ni 90.69(9) Asl - S4 - Ni 90.97(9) aThe estimated standard deviation in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {21.0“ - 1)2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 106 Figure 3-1. Structure and labeling scheme of one [NIAS453]HZB' chain. 107 (A) Figure 3-2 Packing diagram of (Ph4P)2[NiAS433]. (A) view down the a-axis. (B) view down the c-axis 108 (B) 109 undergoes intramolecular condensation. One can argue that the [AS4S3J4' and not the [A828514' unit is of the more appropriate length to accommodate the required number of Ph4P+ cations. Large cations need large empty space, generated by longer thioarsenic polyanions, in order to form a Stable crystal lattice. The empty space generated by the [AS2S5]4' units may be too small for Ph4P+ cations. The (Me4N)2[Mon2AS287] was prepared by heating a mixture of MoO3/K3ASS3/2Me4NCl in sealed Pyrex tube with H20 for one week. Other cations were also tried without much success. The only other cation that afforded crystalline products was Et4N+. The crystal quality of the Et4N+ salt, however, was poor and prohibited further characterization. The structure of (Me4N)2[M0202AS287], determined by X-ray Single-crystal diffraction analysis, revealed that it also contains a one-dimensional chain structure consisting of distorted square pyramidal Mo5+ ions and linear [A8285]4' units formed by corner sharing of ‘ the [AsS3]3' units, see Figure 3-3 and 3-4. The unique feature of this compound is that we still observe the well known M0202S2 fragment which has been seen many times in Mo-S chemistry, for examples, in {M020282(S2)2]2',22 [M020282(S2)2]2',23 and [M020282(S3O2)]2'.24 In these cases, however, the compounds are usually molecular Species. With the introduction of the trivalent As atom, we increase the conductivity of the ligands thus forming a polymeric compound. The Mo-Mo distance of 2.848(2)A is similar to those found in the molecular compounds. There are two types of Mo-S bonds. The average distance between the M0 atoms and bridging sulfur atoms, at 2.335(5)A, is significantly shorter than the 110 average distance, at 2.435(5)A, between the Mo atoms and the terminal S atoms in [AS285]4' units. Similar results were observed in compound [M0202AS4314]2'. The average As-S distance and S-As-S angles are well within the normal range found in other metal thioarsenate compounds like [InAS3S7]2‘ and [SnAS489]2°. Selected bond distances and bond angles are contained in Tables 3-8 and 3-9. It is also noteworthy that in an earlier paper, without Single crystal structure data, Rauchfuss proposed a Structure for [Mo4O4AS4814l4' where two [A8285]4‘ units connect two M0202S2 units.8 The [A82S5]4° unit has been found earlier in the sulfosalts, PleCuAS285(Wallisite),25 PleAgAS2S5(Hatchite),26 and Tl2MnAS285.27 It is interesting to point out that although the size difference between the cations seen in these two compounds, (Ph4P)2[Ni2AS483], and (Me4N)2[M0202AS2S7], is significant, the dimensionality of the two structures remains the same, unlike those found previously, (Ph4P)2[InAS3S7], (Ph4P)2[SnA84S9], and (Me4N)2Rb[BiA85812], where the large cation, Ph4P+, stabilized compounds with low dimensionality while the small cation, Me4N+, stabilized a higher dimensional compound. A correlation, perhaps, can be made between these observations and the length of the thioarsenate ligands. We learned from metal polychalcogenide chemistry that large cations tend to stabilize large clusters and vise versa.28 In the present case, longer thioarsenate ligands, [AS387]S‘, [AS483]4°, and [AS489]6', create larger empty space that can only be filled with large cations, Ph4P+. Changing from a large cation, Ph4P+, to a small cation, 1 1 l Me4N+, the structure has two obvious choices. One is to increase the dimensionality of the compound, which we see in (Me4N)2Rb[BiAS5$12]; the other is to decrease the empty space by using a smaller ligand like [A8285]4' in (Me4N)2[M0202A8287] and remain one-dimensional. A similar argument can be used to explain the structure of (Ph4P)2[M02O2AS4814] which retains the [AS285]4' ligand and thus chooses to decrease its dimension to zero (i.e. cluster). Table 3-8. Selected Distances (A) in (Me4N)2[M0202AS287] with Standard Deviations in Parenthesesfi‘ M01 - M02 2.848(2) M01 - S3 2.337(5) M01 - S4 2.335(5) M01 - SS 2.442(6) M01 - S6 2.425(5) M01 - Ol 1.68(1) M02 - S1 2.435(6) M02 - 82 2.440(5) M02 - S3 2.335(5) M02 - S4 2.334(5) M02 - 02 l.70(l) Asl - SS 2.230(6) Asl - S6 2.236(6) Asl - S7 2.260(6) A82 - S1 2.245(6) A82 - S2 2.240(5) As2 - S7 2.262(6) aThe estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {EnUn - l)2/n(n-1)}1/2, where 1,. is the length (or angle) of the nth bond, 1 the mean length (or angle), and n the number of bonds. 1 12 Table 3-9. Selected Angles (Deg) in (Me4N)2[Mo202AS287] with Standard Deviations in Parentheses.a M02 - M01 - S3 52.4(1) M02 - M01 - S4 52.4(1) M02 - M01 - SS 130.7(1) M02 - M01 - S6 129.4(1) M02 - M01 - Ol 106.5(4) S3 - M01 - S4 101.1(2) S3 - M01 - SS 145.9(2) S3 - M01 - S6 80.1(2) S3 - M01 - Ol 109.2(4) S4 - M01 - S5 80.1(2) S4 - M01 - S6 141.6(2) S4 - Mol - Ol 110.9(4) SS - Mol - S6 78.7(2) S5 - M01 - Ol 101.9(5) S6 - M01 - Ol 104.6(4) M01 - M02 - 8] 130.9(2) M01 - M02 - 82 126.6(1) M01 - M02 - S3 52.5(1) M01 - M02 - S4 52.4(1) M01 - M02 - 02 104.8(4) S1 - M02 - 82 78.0(2) Sl - M02 - S3 144.1(2) S1 - M02 - S4 80.8(2) Sl - M02 - O2 104.7(5) S2 - M02 - S3 77.9(2) S2 - M02 - S4 139.5(2) 82 - M02 - 02 108.6(4) S3 - M02 - S4 101.3(2) S3 - M02 - 02 108.0(5) S4 - M02 - 02 110.0(5) SS - Asl - S6 87.4(2) SS - Asl - S7 108.5(2) S6 - Asl - S7 102.9(2) Sl - A82 - $2 86.3(2) Sl - As2- S7 104.1(2) 82 - As2 - S7 98.3(2) M02 - S1 - A82 92.5(5) M02 - S2 - As2 92.5(2) M01 - S3 - M02 75.1(2) M01 - S4 - M02 75.2(2) ¥Mol - SS - Asl 88.9(2) Mol - S6 - Asl 89.2(2) 113 I:igure 3—3. Structure and labeling scheme of one [M0202A5287]n211- Chain. 114 Flgure 3-4. Packing diagram of (ME4N)2[M0202ASZS7]. 115 3.2 Physicochemical studies In the far-IR region all complexes reported here exhibit spectral absorptions due to As-S and M-S Stretching vibrations as shown in Figure 3-5. Observed absorption frequencies of all the complexes are given in Table 3.10. Table 3.10. Frequencies (cm'l) of Infrared Spectral Absorptions of (Ph4P)2[NiAS488](I), and (Me4N)2[M0202A82$71(II). Eompounds Infrared Raman (Ph4P)2[NiA84Sg} 465(w), 406(m) 395(8). 386(m), 352(m) 386(m), 364(m) 314(8), 301(m), 253(m) 339(w), 320(m) 178(m) 288(8), 212(w) (Me4N)2[M0202A8287] 930(8), 460(8) 930(8), 421(m), 402(m) 407(8, sh), 361(8) 362(8), 274(m), 222(m) 319(8, br), 238(m) 190(m), 170(w) 219(m), 206(w) k * 8: Strong, m; medium, w: weak, sh: shoulder. In the Far-IR spectra of (Ph4P)2[NiAS4Sg], and (Ph4P)2[M02O2AS2S7], the peaks in the region of ‘200-400 cm'1 could be attributed to AS-S Vibration modes. Similar assignments have been made in the far-IR Spectra of other known thioarsenic complexes.” The additional peak in the IR spectra, 460 cm'l, for (Me4N)2[M0202A8287], might be assigned to a Mo-S stretching vibration. For comparison, 455 cm“1 11(5 JL TBflNSMlTTHNCE 961 822' 363 3??7 563* éfié 227 166 File unvzuuneen Figure 3-5. Par-IR spectra (Csl pellets) of (A) (Ph4P)2[NiAS483], and (B) (M84N)2[M0202A82571 117 was assigned as an Mo-Sb (bridging S atoms) vibrational frequency in [M0202AS4S]4]2',8 [M02S5]2‘, [M0287]2', and [M028912230 We also observed the Mo=O stretching mode in (Me4N)2[M0202A8287] at 938 cm'l. The major difficulty in assigning the observed IR spectra of these compounds arises from the fact that As-S and M-S Stretching frequencies fall in the same low frequency region of 150-450 cm'l, FT-Raman spectra of (I) and (II) were also collected (see Table 3-10). There are numerous peaks in the range between 150 to 400 cm'l, just as in the far-IR Spectra. Again, specific assignments were ' difficult since these peaks can be assigned to either the As-S or MS vibration modes. Thermal Gravimetric Analysis (TGA) results for all compounds are summarized in Table 3-11 and Shown in Figure 3-6. Table 3.9. TGA Data for (Ph4P)2[NiAS4S3](I), and (Me4N)2[M0202AS2S7](II). Compound Temp. range (°C) Weight loss (%) (Ph4P)2[NiAS4Sg] 218 - 485 79.5 (Me4N)2[M0202AS2S7] 2 5 0 - 3 3 5 25 .9 45 0— 7 S O 30. 1 (Ph4P)2[NiAS4Sg] Shows a one step weight loss of 79.5 % in the temperature range of 218-485 °C. probably as Ph3PS, other organic species and various AsxSy. An X-ray powder diffraction analysis of 118 1 20 l ‘ (A) .. 100' 'f 80" _. W(%) m 3’ 1 40~ _ 20- 1 1 I 0 200 400 600 800 Temp (°C) 110 1 l 1 100— ¥ (3) - 80 '- _ 7O - .. 60 - .. 50 - - 40 W(%) l I 1 0 200 400 600 800 Temp °( C) Figure 3-6. TGA diagrams of (A) (Ph4P)2[NiAS453], and (B) (Me4N)2[M0202A82851 119 (Ph4P)2[N1AS 488] a/S absorption Coeff. (arb. units) Eg-2.2 eV 0.2- .. 0') I I l l r o l 2 3 4 s 6 7 eV 1 1 l i l 1 i”: 10- .. § - (a) _ ‘5 8.‘ - ‘3? 6- _ U - a .. .2 4- _ 2‘3 - - g 2- ' (Me4N)2[M0202A8257] _ é, .. Eg=2.SeV _ R 1 O l I l .l l | 0 1 2 3 4 S 6 7 eV Figure 3-7. Optical absorption spectra of (A) (Ph4P)2[NiAS453], and (B) (Me4N)2N0202A82551 120 the final residues indicates the presence of NiASS and other phases that can not be identified. (Me4N)2[M02O2A82S7] shows a two step weight loss in the temperature range of 250-335 and 450-750 °C. The first step is probably due to loss of Me3N and Me2S. In the (Me4N)2[M0202A82S7] case, weight 1088 continues above 800 °C. The final product was proved to be MoS2 by X-ray powder diffraction. The thermal behavior of both compounds was further investigated by differential thermal analysis (DTA). Neither shows any melting before the decomposition temperature. The optical properties of (Ph4P)2[NiA8483] and (Me4N)2[M02O2A8287] were assessed by studying the UV-visible-near IR spectra of the material. The spectra confirm that they are wide band-gap semiconductors. The optical absorption spectrum of (Ph4P)2[NiAS4Sg], shown in Figure 3-7(A), exhibits an intense, steep absorption edge, revealing an optical bandgap of 2.2 eV. The spectrum of (Me4N)2[M02O2A8287] also shows a similar absorption edge with a corresponding bandgap at 2.5 eV, see Figure 3-7(B). The absorption is probably due to a charge-transfer transition from a primarily sulfur-based valence band to a mainly metal-based conduction band. In conclusion, hydrothermal synthesis methods readily promote synthesis and crystallization of new compounds which in many cases can not be achieved by classical solution technique. Using ASS33' as starting material has given access to new and exciting metal/arsenic/8ulfide chemistry and promises to do so for other unexplored systems as well. The key to this chemistry is the 121 condensation equilibria which exist in the reaction medium as well as the coordination preferences of the metal ions. Further investigations are needed to explore the existence of other novel [AsxSyP' anions and the possibility of using them as building blocks toward new solid state materials. 122 REFERENCES (a) Liao, J.-H.; Kanatzidis, M. G. Inorg. Chem. 1992,31, 431-439. (b) Liao, L.-H.; Kanatzidis, M. G. J. Am. Chem. Soc. 1990, 112, 7400-7402. (C) Huang, S.-P.; Kanatzidis, M. G. J. Am. Chem. Soc. 1992, 114, 5477-5478. (a) Sheldrick, W. 8. Z. Anorg. Allg. Chem. 1988, 562, 23-30. (b) Shedrick, W. S.; Hanser, H.-J. Z. Anorg. Allg. Chem. 1988,557, 98-104. (c) Shedrick, W. 8.; Hanser, H.-J. Z. Anorg. Allg. Chem. 1988,557, 105-110. a) Wood, P. T.; Pennington, W. T.; Kolis, J. W. Inorg. Chem. 1993, 32, 129-130. b) Wood, P. T.; Pennington, W. T.; Kolis, J. W. J. Chem. Soc. Chem. Commun. 1993,25, 235-236. Chou, J.-H.; Kanatzidis, M. G. Inorg. 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Nauk SSR Neorg. Mater. 1971, 7, 27-30. Hadjikyriacou, A. I.; Coucouvanis, D. Inorg. Chem. 1987,26, 2400-2408. 126 CHAPTER 4 HYDRO(SOLVO)THERMAL SYNTHESIS OF DISCRETE MOLECULAR M/AsxSy (M = Pt“, Pt2+ Pd“) ANIONS. SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (Ph4P)2[Pt(AS385)2](I), (Ph4P)2K[Pt3(AsS4)3](II). AND (Ph4P)2K1P63(AsS4)3l(III). 127 ABSTRACT (Ph4P)2[Pt(AS3Ss)2](I) and (Ph4P)2K[Pt3(ASSa)3]-1.5H20(II) were synthesized hydrothermally from a mixture of PtC12/3K3ASS3/4Ph4PBr and PtC12/2K3ASS3/4Ph4PBr, respectively, in 0.3 mL of water heated at 110 °C for one day. Both crystallize in the triclinic space group P-l (No. 2) with unit cell dimensions a = 13.104(3)A, b = 20.519(4)A, c = 11.559(2)A, a = 105.72(2)°, p: 108.09(2)°, y = 75.11(2)°, v = 2793(2) A3, 2 = 2 for (Ph4P)2[Pt(AS3Ss)2], and a = l4.655(2)A, b l7.852(3)A, c = 14.253(2)A, a = 109.65(2)°, fl = 118.89(2)°, y = 72.08(3)°, V = 3027(1)A3, z = 2 for (Ph4P)2K[Pt3(AsS4)3]-1.5H2O. (Ph4P)2K[Pd3(AsS4)3]-3MeOH(III) was synthesized methanothermally by heating a mixture of PdCl2/3K3ASS3/4Ph4PBr in 0.4 mL of MeOH at 110 °C for one day. (Ph4P)2K[Pd3(AsS4)3]-3MeOH also crystallized in the triclinic space group P-l (No. 2) with unit cell dimensions a = 14.171(3)A, b 18.198(3)A, c = l4.154(3)A, a = 106.62(2)°,p= 114.66(2)°, y = 73.88(2)°, v = 3125(2) A3,z = 2. (Ph4P)2[Pt(A83Ss)2] is a molecular cage compound consisting of [Pt(AS355)2]2' anions. The Pt atom has a 4+ formal oxidation state and is coordinated to four S atoms and two As atoms in octahedral fashion. The two As atoms are disposed in a cis-fashion around the metal center and the Pt-As bond length is 2.454(2)A. The [Pt3(AsS4)3]3' and [Pd3(AsS4)3]3‘ anions are isostructural with essentially square planar Pt2+ and N“ centers. The [A884]3' ligand contains A834. and represents a new isomer of the known tetrahedral As5+ species. 128 1. Introduction Pt4+ complexes are both thermodynamically stable and kinetically inert. Those with halides, pseudo-halides and N-donor ligands are especially numerous.1 While oxygen-donor ligands such as OH' and acac (acac = acetylacetonate) also coordinate to Pt4+, sulfide and selenide, and especially P- and As- donor ligands, tend to reduce it to Pt”.2 Notable exceptions are [Pt(S5)3]2',3 [Pt484(S3)5]4',4 and [Pt(Se4)3]2'.5 Pd4+ complexes, on the other hand, are very unstable and would rather stay at 2+ oxidation state with respect to polychalcogenide ligands. Recently, it has been shown that hydrothermal conditions offer significant advantages in new cluster and solid state compound synthesis.5-7v8 We have exploited the high reactivity and lability of the ASS33' pyramidal unit in conjunction with main group elements (see chapter 2) and some transition metals (see chapter 3) and reported on the hydrothermal synthesis of several unusual one- and two-dimensional solids containing organic cations, including (Ph4P)2[InAS3S7],9 (Ph4P)2[SnAS489], (Me4N)2Rb[BiA86812],9 (Ph4P)2[NiAS483], and (Me4N)2[M0202A82$7]. Our work with AsS33‘ solutions thus far suggests the existence of very complex condensation equilibria in solution where a variety of [AsxSyP' species might be present. The type and identity of [AsxSeyF' fragment found in the isolated solids depends on the particular counterion present and on the metal size and coordination preference. Thus far, we have identified several types of [ASxSyJZ' ligands including [AS386]3',10 [AS285]4', [AS3S715',9[AS483]4',and [AS48916‘. The chemistry of Pt“ and Pt“+ polysulfides goes back to 129 the beginning of this century and even to this date it has proven remarkably complex, mostly due to the lability of 83' species and redox processes in solution. The great lability of A8833‘ and its higher [ASxSyP' homologs, and the conceptual relationship of A8833' to sz' (e.g. the former derives from 83' via a S atom substitution by an isoelectronic AS' ion) raises interesting prospects for similar chemistry in the Pt/AsS33' system. In fact, we observed not only the familiar Pt2+ vs. Pt‘l+ redox couple, but also an unusual kind of Pt-As bonding and several new thioarsenate ligands which emerge as new features in this chemistry. We describe here three unique clusters, [Pt(AS3SS)2]2'(I), [Pt3(AsS4)3]3'(II), [Pd3(ASS4)3]3'(III), formed under hydro(solvo)thermal conditions. 2. Experimental Section 2.1 Reagents Chemicals. Chemicals, other than solvents, were used as obtained. PtCl2, 98% purity, PdCl2, 99% purity, tetraphenylphosphonium bromide (Ph4PBr), 98% purity, Aldrich Chemical Company, Inc., Milwaukee, WI. A3AsS3 (A = K, Rb, Cs) were synthesized by using stoichiometric amounts of alkali metal, arsenic sulfide (A82S3), and sulfur in liquid ammonia. The reaction gives a yellow brown powder upon evaporation of ammonia. 13 0 2.2 Syntheses All syntheses were carried out under a dry nitrogen atmosphere in a Vacuum Atmosphere Dri-Lab glovebox except were specifically mentioned. (Ph4P)2[Pt(AS3Ss)2](I): A Pyrex tube (.4 mL) containing a mixture of PtC12 (65mg, 0.25mmol), K3ASS3 (144mg, 0.75mmol), Ph4PBr (419 mg, 1.0mmol) and 0.3 mL of water was sealed under vacuum and kept at 110 °C for one day. The large red platelike crystals that formed were isolated in methanol and washed with ether. (Yield=74.3 % based on Pt). Semiquantitative elemental analysis of the red crystals obtained by using a SEM/EDS technique gave the P:Pt:As:S ratio at 1.8:1.0:S.0:10.0. (Ph4P)2K[Pt3(A8S4)3]-l.5 H20(II): A mixture of PtC12 (65mg, 0.25mmol), K3ASS3 (96mg, 0.5mmol), Ph4PBr (419 mg, 1.0mmol) and 0.3 mL of water was sealed under vacuum and kept at 110 °C for one day. A mixture of red plate-like crystals of (Ph4P)2[Pt(AS3S5)2] and yellow plate-like crystals of (Ph4P)2K[Pt3(ASS4)3]-l.5 H20 were isolated, by washing with methanol and ether, in 1:4 ratio with (Ph4P)2K[Pt3(AsS4)3]-1.5 1120 as the major product. (Yield = 85.4%, based on Pt). Semiquantitative elemental analysis of the yellow crystals obtained by uSing a SEM/EDS technique gave the P:K:Pt:As:S ratio as 1.7:1:3:2:11.8. (PI-I4P)2K[Pd3(ASS4)3]-3MeOH(III): A Pyrex tube (-4 mL) containing a mixture of PdCl2 (45mg, 0.25mmol), K3ASS3 (144mg, 0.75mmol), Ph4PBr (419 mg, l.0mmol) and 0.3 mL of methanol was 13 1 sealed under vacuum and kept at 110 °C for one day. The large red rod-like crystals that formed were isolated in methanol and washed with ether. (Yield=74.3 % based on Pd). Semiquantitaitive elemental analysis of the red crystals obtained by using a SEM/EDS technique gave the P:K:Pd:As:S ratio at 1.8:1.0:2.5:3.2:11.0. 2.3. Physical Measurements The instruments and experimental setups for Infrared measurements, thermal analysis and quantitative microprobe analysis on SEM/EDS are the same as those described in Chapter 2. 2.4 X-ray crystallography (Ph4P)2[Pt(AS3S5)2]: A well Shaped dark red platelike crystal with dimensions of 0.55 x 0.55 x 0.35 mm was mounted on a glass fiber. Single-crystal X-ray diffraction data were collected at -100 °C on a Rigaku AFC6 diffractometer. A total of 7879 independent reflections was collected. ‘All nonhydrogen and non-carbon atoms were refined anisotropically. All hydrogen atom positions were calculated and fixed without further refinement. (Ph4P)2K[Pt3(AsS4)3]-l.5 H20 : The yellow platelike crystal used for the study had approximate dimensions of 0.45 x 0.53 x 0.35 mm. The crystal was mounted on a glass fiber. Single-crystal X-ray diffraction data were collected at -100 °C on a Rigaku AFC6 diffractometer. A A total of 8545 reflections were collected. All 132 nonhydrogen and non-carbon atoms were refined anisotropically. All hydrogen atom positions were calculated and fixed without further refinement. (Ph4P)2K[Pd3(AsS4)3]-3CH3OH: The red rod-like crystal with dimensions of 0.55 x 0.65 x 0.75 mm was mounted on a glass fiber. Single-crystal X-ray diffraction data were collected at -100 °C on a Rigaku AFC6 diffractometer. A total of 8763 independent reflections was collected. All nonhydrogen and non-carbon atoms were refined anisotropically. All hydrogen atom positions were calculated and fixed without further refinement. The crystals did not show any significant intensity decay as determined by monitoring 3 check reflections every 150 reflections throughout data collection. The Structures were solved by direct methods (SHELXS-86)11 and refined with the TEXSAN12 software package. An empirical absorption correction (DIFABSI3) was applied to the isotropically refined data. All non-hydrogen atoms except nitrogen and carbon were refined anisotropically. All calculations were performed on a VAXstation 3100 Model 76 computer. Table 4.1 summarizes the crystallographic data and details of the structure solution and refinement. The final atomic coordinates with their estimated standard deviations (esd's) are given in Tables 4.2 - 4.4. 133 Table 4-1. Crystallographic Data for (Ph4P)2[Pt(AS3S5)2](I) and (Ph4P)2K[Pt3(AsS4)3] - 1.5 H20(II). I I I Formula C43H4oP2PtA86810 C43H43P201,5KPt3AS3S12 F. w. 1642.6 1938.1 a, A 13.104(2) l4.655(2) h, A 20.519(3) l7.852(2) c, A 11.559(2) 14.252(2) 01, deg. 105.72(2) 109.65(2) 8, deg. 108.09(2) 118.88(2) 7, deg. 75.11(2) 72.08(2) z,v, A3 2, 2793(2) 2, 3027(2) Space Group P-I (No. 2) P-I (No. 2) color, habit orange red, plate yellow, plate Dcaic. g/cm3 1.95 2.13 Radiation Mo K01 Mo K01 11, cm'1 65.09 91.68 29malts deg. 45.0 45.0 Absorption Correction \v scan w scan Transmission Factors 0.76-1.12 0.66-1.25 Index ranges No. of Data coll. Unique reflections Data Used (Fo2 > 30(Fo2)) No. of Variables Final Ralwa, % 05h516,-24gk_<_ 24, -14_<_is_14 7702 7316 3810 364 4.0/5.0 Oghg 17, -215kg 21, -17 $1517 8319 7924 3908 390 7.7/9.5 3 R: Z(|Fo|-|Fc|)/2|Fo|, b Rw={£w(|Fo|-|Fcl)2/}3wlF0|2} 1/2 134 Table 4-1. (cont'd) Crystallographic Data for (Ph4P)2K[Pd3(AsS4)3] - 3CH3OH(III). III Formula C51H52P203KPd3A83812 F. w. 1741.1 a, A 14.17l(3) h, A 18.198(5) c, A l4.154(3) 01, deg. 106.62(2) B, deg. 114.66(2) 7, deg. 83.88(2) z,v, A3 2, 3125(2) Space Group P-I (No. 2) color, habit orange red, plate Dcalc. g/cm3 1.85 Radiation Mo Kill 11, cm'1 29.58 29m“, deg. 45 .00 Absorption Correction ll! scan Transmission Factors 0.88-1.06 Index ranges 0 g h s 15, -20 g k g 20, -15 g 1 g 15 No. of Data 0011. 8580 Unique reflections 81 7 9 Data Used 6091 (Fo2 > 30(Fo2)) No. of Variables 421 Final Ralwa, % 3.4/4.4 a R: 2(lFol-chl)/2|Fol, b Rw={2w(|Fol-|Fc|)2/2wlFo|2} 1’2 135 Table 4-2. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[Pt(AS385)2](I). atom X Y Z Beg a, (A2) Pt 0.29073(6) 0.26542(4) 0.36578(6) 3.44(3) As(l) 0.0160(2) 0.3817(1) 0.3141(2) 5.8(1) As(2) 0.0477(2) 0.1895(1) 0.3083(2) 6.3(1) As(3) 0.1891(2) 0.2489(1) 0.1458(2) 4.5(1) As(4) 0.5286(2) 0.2677(1) 0.2587(2) 5.3(1) As(S) 0.3832(2) 0.1489(1) 0.2874(2) 4.8(1) As(6) 0.5711(2) 0.2172(1) 0.5698(2) 5.3(1) 8(1) 0.0609(4) 0.3462(3) 0.1317(4) 5.5(3) . 8(2) -0.0606(5) 0.2947(3) 0.3192(5) 7.0(3) S(3) 0.0848(5) 0.1702(3) 0.1251(4) 6.0(3) S(4) 0.1783(4) 0.3730(2) 0.4423(4) 5.0(2) 8(5) 0.2055(4) 0.2033(3) 0.4400(4) 5.1(3) 8(6) 0.4792(5) 0.1667(3) 0.1686(5) 5.7(3) 8(7) 0.6427(4) 0.2548(3) 0.4487(5) 5.8(3) 8(8) 0.5207(4) 0.1191(2) 0.4505(5) 5.5(3) 8(9) 0.3754(4) 0.3311(2) 0.2975(4) 4.7(2) 8(10) 0.4124(4) 0.2833(2) 0.5734(4) 4.6(2) P(l) 0.6829(4) 0.4706(2) 0.8555(4) 3.7(2) P(2) 0.2286(4) 0.0510(2) 0.6782(4) 3.9(2) C(l) 0.681(1) 0.3924(8) 0.897(1) 4.3(4) C(2) 0.582(2) 0.375(1) 0.890(2) 5.1(4) C(3) 0.586(2) 0.318(1) 0.933(2) 5.8(4) C(4) 0.682(2) 0.278(1) 0.976(2) 6.0(5) C(S) 0.780(2) 0.293(1) 0.984(2) 6.4(5) C(6) 0.779(1) 0.3498(9) 0.939(1) 4.5(4) C(7) 0.711(1) 0.5356(8) 0.993(1) 3.6(3) C(8) 0.721(1) 0.600(1) 0.983(2) 5.0(4) C(9) 0.740(2) 0.651(1) 1.091(2) 5.7(4) C(10) 0.747(1) 0.6387(9) 1.204(2) 4.7(4) C(11) 0.736(2) 0.577(1) 1.215(2) 5.4(4) C(12) 0.719(1) 0.5263(8) 1.110(1) 4.3(4) C(13) 0.791(1) 0.4535(8) 0.782(1) 3.4(3) C(14) 0.782(2) 0.411(1) 0.665(2) 6.1(5) C(15) 0.868(2) 0.393(1) 0.608(2) 6.8(5) C(16) 0.960(2) 0.419(1) 0.671(2) 7.0(5) C(17) 0.973(2) 0.459(1) 0.785(2) 8.6(6) C(18) 0.885(2) 0.476(1) 0.840(2) 7.2(5) 136 C(19) 0.550(1) 0.4975(8) 0.760(1) 3.7(3) C(20) 0.507(2) 0.454(1) 0.647(2) 6.0(5) C(21) 0.398(2) 0.475(1) 0.580(2) 7.0(5) C(22) 0.337(2) 0.532(1) 0.625(2) 5.8(4) C(23) 0.378(2) 0.575(1) 0.735(2) 6.2(5) C(24) 0.485(2) 0.5573(9) 0.803(2) 4.9(4) C(25) 0.223(1) 0.0098(8) 0.521(1) 3.3(3) C(26) 0.149(2) -0.032(1) 0.454(2) 5.6(4) C(27) 0.141(2) -0.064(1) 0.328(2) 6.1(5) C(28) 0.206(2) -0.047(1) 0.273(2) 6.8(5) C(29) 0.277(2) -0.004(1) 0.335(2) 6.0(5) C(30) 0.287(1) 0.0241(9) 0.460(2) 4.8(4) C(31) 0.125(1) 0.1278(8) 0.681(1) 4.0(4) C(32) 0.125(2) 0.177(1) 0.792(2) 5.0(4) C(33) 0.037(2) 0.230(1) 0.795(2) 6.6(5) C(34) -0.047(2) 0.237(1) 0.694(2) 6.1(5) C(35) -0.046(2) 0.191(1) 0.583(2) 5.5(4) C(36) 0.039(1) 0.1362(9) 0.577(2) 4.5(4) C(37) 0.357(1) 0.0733(8) 0.756(1) 4.1(4) C(38) 0.383(2) 0.1345(9) 0.743(2) 5.0(4) C(39) 0.487(2) 0.151(1) 0.804(2) 5.5(4) C(40) 0.562(2) 0.107(1) 0.874(2) 5.7(4) C(41) 0.541(2) 0.050(1) 0.890(2) 5.3(4) C(42) 0.439(1) 0.0291(8) 0.827(1) 3.7(3) C(43) 0.199(1) -0.0043(8) 0.755(1) 3.6(3) C(44) 0.235(1) -0.0764(9) 0.725(2) 4.6(4) C(45) 0.215(2) -0.118(1) 0.785(2) 5.6(4) C(46) 0.167(2) -0.092(1) 0.881(2) 5.2(4) C(47) 0.133(2) -0.023(1) 0.914(2) 5.6(4) C(48) 0.149(2) 0.022(1) 0.854(2) 5.4(4) 137 Table 4-3. Selected Atomic Coordinates and Estimated Standard Deviations (esd‘s) of (Ph4P)2K[Pt3(AsS4)3]-1.5H2O(II). atom X Y Z B851 3, (A2) Pt(1) 0.3076(1) 0.2512(1) 0.9752(1) 3.18(8) Pt(2) 0.0702(1) 0.1956(1) 0.8535(1) 3.30(8) Pt(3) 0.1863(2) 0.2576(1) 1.1295(2) 4.4(1) As(l) 0.3980(4) 0.3779(3) 1.2596(4) 5.5(3) As(2) 0.1572(4) 0.2403(3) 0.6771(4) 5.0(3) As(3) -0.0973(5) 0.2500(5) 1.0013(6) 8.4(4) K(1) 0.096(1) 0.4002(7) 0.958(1) 7.1(7) S(1) 0.127(1) 0.1416(8) 1.003(1) 5.1(7) 8(2) 0.2360(9) 0.1370(5) 0.8622(9) 3.1(5) S(3) 0.344(1) 0.1973(7) 1.120(1) 4.2(6) S(4) 0.016(1) 0.2513(8) 0.703(1) 4.7(6) S(5) 0.249(1) 0.3736(8) 1.257(1) 5.2(7) 8(6) 0.266(1) 0.3084(8) 0.831(1) 5.2(7) S(7) 0.363(1) 0.3742(8) 1.089(1) 5.6(7) 8(8) 0.469(1) 0.2468(9) 1.260(1) 6.8(7) 8(9) 0.234(1) 0.1165(8) 0.707(1) 6.2(7) S(10) -0.094(1) 0.256(1) 0.848(1) 6.1(7) S(ll) 0.026(1) 0.317(1) 1.135(1) 8(1) S(12) -0.001(1) 0.124(1) 1.013(2) 9(1) P(l) 0.5250(9) 0.1718(6) 0.633(1) 3.1(5) P(2) 0.8292(9) 0.3118(7) 0.343(1) 3.4(5) 0(1) -0.088(6) 0.443(5) 0.986(6) 8(2) 0(2) -0.095(7) 0.464(6) 0.834(7) 27(2) C(l) 0.346(3) 0.104(2) 0.534(3) 2.8(8) C(2) 0.397(3) 0.155(2) 0.527(3) 2.1(7) C(3) 0.965(4) 0.399(3) 0.537(4) 4(1) C(4) 0.524(3) 0.278(2) 0.691(3) 3.4(8) C(5) 0.946(3) 0.352(2) 0.433(3) 3.3(8) C(6) 0.660(4) 0.085(3) 0.418(4) 6(1) C(7) 0.758(3) 0.356(2) 0.224(3) 2.6(7) C(8) 0.865(3) 0.200(2) 0.305(3) 2.9(8) C(9) 0.722(4) 0.129(3) 0.639(4) 5(1) C(10) 0.248(3) 0.092(2) 0.452(3) 3.4(8) C(11) 0.505(4) 0.443(3) 0.765(4) 5(1) C(12) 0.425(3) 0.409(2) 0.738(3) 3.0(8) C(13) 0.758(4) 0.086(3) 0.480(4) 6(1) 138 C(14) 0.627(3) 0.048(3) 0.742(4) 4(1) C(15) 0.588(3) 0.111(3) 0.465(4) 4(1) C(16) 0.802(3) 0.403(2) 0.206(3) 3.7(9) C(17) 0.624(3) 0.134(3) 0.577(3) 3.9(9) C(18) 0.249(4) 0.185(3) 0.364(4) 5(1) C(19) 0.732(3) 0.290(3) 0.457(3) 3.8(9) C(20) 0.428(3) 0.326(3) 0.696(3) 3.8(9) C(21) 0.342(4) 0.195(3) 0.440(4) 5(1) C(22) 0.704(3) 0.425(3) 0.431(3) 4(1) C(23) 0.747(3) 0.344(3) 0.413(3) 3.5(9) C(24) 0.610(3) 0.313(3) 0.729(3) 4(1) C(25) 0.675(4) 0.318(3) 0.517(4) 5(1) C(26) 0.526(4) 0.155(3) 0.816(4) 5(1) C(27) 0.566(3) 0.119(2) 0.739(3) 3.2(8) C(28) 0.601(4) 0.395(3) 0.769(4) 5(1) C(29) 0.546(4) 0.115(3) 0.899(4) 6(1) C(30) 0.602(4) 0.034(3) 0.891(4) 6(1) C(31) 0.648(4) 0.005(3) 0.824(4) 5(1) C(32) 0.199(4) 0.131(3) 0.366(4) 6(1) C(33) 0.793(4) 0.106(3) 0.585(4) 7(1) C(34) 0.741(5) 0.439(3) 0.112(5) 7(1) C(35) 0.650(5) 0.425(4) 0.052(5) 8(2) C(36) 0.655(4) 0.342(3) 0.155(4) 6(1) C(37) 0.649(4) 0.453(3) 0.497(4) 5(1) C(38) 0.628(4) 0.402(3) 0.537(4) 6(1) C(39) 1.114(4) 0.373(3) 0.468(4) 5(1) C(40) 1.027(4) 0.337(3) 0.398(4) 5(1) C(41) 1.127(4) 0.417(3) 0.565(4) 6(1) C(42) 1.049(4) 0.433(3) 0.607(4) 6(1) C(43) 0.923(4) 0.041(3) 0.261(4) 6(1) C(44) 0.963(4) 0.072(3) 0.365(4) 6(1) C(45) 0.929(4) 0.163(3) 0.389(4) 7(1) C(46) 0.830(4) 0.169(3) 0.200(4) 7(1) C(47) 0.860(5) 0.082(4) 0.177(5) 8(1) C(48) 0.594(5) 0.375(4) 0.053(5) 9(2) a ch=(4/3)[a2811 + b2B22 +c2B33 + ab(cosy)B12 + ac(cosB)B13 + bc(cosa)B23] 139 Table 4-4. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2K[Pd3(AsS4)3]-3CH3OH(III). atom X Y Z Bel 3, (A2) Pd(1) 0.49331(4) 0.23698(3) 0.26342(4) l.82(2) Pd(2) 0.23334(4) 0.24512(3) 0.18603(4) 2.00(2) Pd(3) 0.32695(5) 0.3204(3) 0.06042(5) 2.26(3) As(l) 0.40500(6) 0.10223(5) 0.34925(6) 255(4) As(2) 0.607930) 0.26619(5) 0.08872(7) 3.06(4) As(3) 0.054030) 0.286770) -0.07283(8) 4.56(5) 1((1) 0.3767(2) 0.1145(1) 0.0211(2) 4.2(1) 8(1) 0.6252(2) 0.1871(1) 0.1923(2) 2.69(9) 8(2) 0.5261(2) 0.1121(1) 0.2940(2) 271(9) S(3) 0.4552(1) 0.3595(1) 0.2232(1) 2.24(8) S(4) 0.3672(1) 0.2876(1) 0.3418(1) 206(8) S(5) 0.2518(2) 0.1229(1) 0.2186(2) 274(9) 8(6) 0.1027(2) 0.2010(1) 0.0295(2) 4.0(1) s0) 0.2111(2) 0.3680(1) 0.1516(2) 2770) 8(8) 0.4429(2) 0.2690(1) -0.0282(2) 3.1(1) 8(9) 0.1986(2) 0.2816(1) -O.1028(2) 3.7(1) S(10) 0.3952(2) 0.2208(1) 0.4521(2) 2.84(9) S(ll) 0.5803(2) 0.3789(1) 0.1985(2) 3.5(1) S(12) 0.0586(2) 0.3953(2) 0.0491(2) 4.9(1) P(l) 0.6144(2) 0.3548(1) 0.7526(1) 1.85(8) P(2) 0.0369(2) 0.1695(1) 0.4113(2) 206(8) 0(1) 0.0629(5) 0.3793(5) 0.7045(5) 6.0(4) 0(2) 0.5954(7) 0.0421(4) -0.0056(6) 6.4(4) 0(3) 0.3531(7) 0.0473(5) 0.1807(6) 7.9(5) C(l) 0.4733(5) 0.3685(4) 0.7074(5) 1.9(1) C(2) 0.4261(5) 0.3431(4) 0.7577(5) 2.0(1) C(3) 0.3177(6) 0.3559(4) 0.7252(6) 2.1(1) C(4) 0.2554(6) 0.3933(4) 0.6416(6) 2.2(1) C(5) 0.3017(6) 0.4175(4) 0.5894(6) 2.6(1) C(6) 0.4096(6) 0.4060(4) 0.6219(6) 2.2(1) C(7) 0.6717(5) 0.2547(4) 0.7684(5) 1.9(1) C(10) 0.7659(6) 0.1014(4) 0.7895(6) 2.6(2) C(11) 0.8225(6) 0.1614(5) 0.8463(6) 3.0(2) C(12) 0.7739(6) 0.2385(4) 0.8365(6) 2.6(1) C(13) 0.6669(6) 0.4168(4) 0.8785(6) 2.1(1) C(14) 0.7606(6) 0.4431(4) 0.9065(6) 2.6(1) 11111 [1‘1 {‘4 .(. (1‘ ( ['1‘ 11‘. (11‘. ( (t (. ( { [ ( I." .‘l‘ 111 I1 I l 1 140 C(15) 0.8038(6) 0.4860(5) 1.0081(6) 3.0(1) C(16) 0.7561(6) 0.5010(5) 1.0799(6) 3.1(2) C(17) 0.6650(7) 0.4758(5) 1.0536(7) 3.5(2) C(18) 0.6190(6) 0.4343(5) 0.9523(6) 2.8(2) C(19) 0.6478(5) 0.3761(4) 0.6557(5) 1.8(1) C(20) 0.6568(5) 0.3186(4) 0.5687(5) 2.0(1) C(21) 0.6724(6) 0.3384(4) 0.4894(6) 2.4(1) C(22) 0.6767(6) 0.4136(4) 0.4940(6) 2.6(1) C(23) 0.6658(6) 0.4713(4) 0.5794(6) 2.7(2) C(24) 0.6516(6) 0.4528(4) 0.6600(6) 2.3(1) C(25) 0.1750(5) 0.1372(4) 0.4862(5) 2.0(1) C(26) 0.2256(6) 0.0628(4) 0.4570(6) 2.4(1) C(27) 0.3265(6) 0.0358(5) 0.5223(6) 2.8(2) C(28) 0.3764(6) 0.0832(5) 0.6150(6) 2.9(2) C(29) 0.3275(6) 0.1581(5) 0.6440(6) 2.8(2) C(30) 0.2265(6) 0.1864(4) 0.5795(6) 2.6(1) C(31) 0.0153(6) 0.2677(4) 0.3954(5) 2.1(1) C(32) 0.0889(6) 0.2914(4) 0.3745(6) 2.6(1) C(33) 0.0661(6) 0.3636(5) 0.3497(6) 3.1(2) C(34) -0.0295(8) 0.4127(6) 0.3426(7) 4.6(2) C(35) -0.103(1) 0.3883(7) 0.3619(9) 6.3(3) C(36) -0.0802(8) 0.3157(6) 0.3894(8) 4.8(2) C(37) -0.0054(6) 0.1080(4) 0.2828(6) 2.4(1) C(38) -0.0276(8) 0.1355(6) 0.1933(8) 4.7(2) C(39) -0.065(1) 0.0863(7) 0.094(1) 6.7(3) C(40) -0.0777(8) 0.0133(6) 0.0842(8) 4.9(2) C(41) -0.0540(6) -0.0145(5) 0.1730(7) 3.3(2) C(42) -0.0183(6) 0.0326(5) 0.2716(6) 3.0(2) C(43) -0.0399(5) 0.1615(4) 0.4809(5) 2.0(1) C(44) 0.0028(6) 0.1699(5) 0.5912(6) 3.0(2) C(45) -0.0579(7) 0.1630(5) 0.6429(7) 3.5(2) C(46) -0.1566(6) 0.1442(5) 0.5858(6) 2.9(2) C(47) -0.1978(6) 0.1355(5) 0.4787(6) 3.0(2) C(48) -0.1403(6) 0.1450(4) 0.4253(6) 2.8(2) C(49) 0.6122(8) 0.0694(6) -0.0809(8) 4.9(2) C(50) 0.2487(9) 0.0418(6) -0.2444(8) 5.4(2) C(51) -0.042(1) 0.4046(7) 0.696(1) 6.5(3) a ch=(4/3)[a2B11 + sz22 +c2B33 + ab(cosy)B12 + ac(cosB)Bl3 + b¢(cosa)323] spa cal co: mc dal co< pal CE d-s Ta‘ 141 The compounds were examined by X-ray powder diffraction for the purpose of phase purity and identification. Accurate dhkl spacings (A) were obtained from the powder patterns recorded on a calibrated (with FeOCl as internal standard) Phillips XRG-3000 computer-controlled powder diffractometer with praphite- monochromated Cu K01 radiation operating at 35 kV and 35 mA. The data were collected at a rate of 0.12°lmin. Based on the atomic coordinates from X-ray single crystal diffraction study, X-ray powder . patterns for all compounds were calculated by the software package CERIUS.14 Calculated and observed X-ray powder patterns that Show d-spacings and intensities of strong hkl reflections are complied in Tables 4-5 to 4-7. 142 Table 4-5. Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[Pt(AS385)2](I)- h k I am, (A) dag, (A) I/Imohs, %) 1 o 0 12.23 12.21 10 1 1 0 11.36 11.35 82 o 0 2 10.75 10.74 47 0 1 -1 10.36 10.35 62 0 2 0 9.69 9.69 77 1 -1 0 9.56 9.55 41 l o -1 9.36 9.36 51 o 1 1 8.67 8.66 100 1 2 -1 8.20 8.20 70 0 2 -1 8.08 8.08 15 1 -1 -l 7.53 7.53 10 1 0 1 7.20 7.20 10 1 1 1 6.69 6.68 12 0 2 l 6.55 6.55 12 l 3 o 6.22 6.22 17 0 3 -1 6.13 6.12 20 1 -2 -1 5.85 5.85 14 1 2 -2 5.51 5.50 15 0 l -2 1 0 -2 5.47 5.47 15 0 0 2 5.37 5.37 15 2 3 -1 5.28 5.28 15 0 3 1 5.09 5.08 15 1 4 -1 5.03 5.02 17 2 -1 1 4.60 3 -1 o 3.84 3 4 -1 3.71 3.71 10 2 -4 0 3.49 3.49 11 3 5 -2 3.26 3.26 15 3 5 -3 2.945 2.941 10 2 -1 3 2.793 143 Table 4-6. Calculated and Observed X—ray Powder Diffraction Pattern of (Ph4P)2K[Pt3(ASS4)3]-l .SH2O(II) h k 1 am (A) am (A) I/IMLobs, %) 1 o 0 12.6 12.5 20 0 0 1 12.2 12.1 62 1 1 -1 11.8 11.7 57 1 o -1 11.5 11.4 10 1 -1 0 9.28 9.27 58 o 2 0 8.28 8.27 100 1 -1 -l 8.14 8.14 35 0 2 -1 7.69 7.68 67 1 2 0 7.56 7.55 12 1 0 1 7.34 7.34 9 2 0 -1 6.93 6.92 13 1 -1 1 6.79 6.79 15 1 3 0 4.75 4.75 12 o 4 -1 4.21 4.21 13 2 3 -5 2.79 Table 4-7. Calculated and Observed X-ray Powder Diffraction Pattern 144 of (Ph4P)2K[Pd3(AsS4)3]-3CH3OH(III). h k i am (A) dies (A) ”’m (obs, %) 1 0 0 12.67 12.66 75 0 0 12.61 12.60 38 0 1 -1 11.26 11.25 90 l 1 -1 1 l 0 11.21 11.21 75 1 o -1 1 -1 0 9.40 9.40 45 0 1 9.33 9.33 95 o 2 o 8.57 8.55 100 1 -1 -1 8.22 8.22 34 1 0 1 7.64 7.64 19 1 1 -2 7.01 7.00 15 1 0 -2 6.71 6.71 17 0 2 1 6.53 6.53 16 1 3 -1 5.96 1 2 1 5.69 5.70 22 0 3 1 4.86 4.86 20 2 1 l 1 -2 -2 4.65 4.64 14 4 1 -3 3.28 3.28 20 1 5 -3 3.18 3.18 10 145 3. Results and discussion 3.1 Syntheses and Description of Structures _ (Ph4P)2[Pt(AS385)2] was prepared by heating a mixture of PtCl2/3K3ASS3/4Ph4PBr in a sealed Pyrex tube with 0.3 mL of H20 for one day. The orange-red platelike crystals of (Ph4P)2[Pt(AS385)2] are relatively air stable and soluble in polar organic solvents such as DMF and CH3CN and give orange-red solutions, indicative that the compound might be a molecular complex. The structure was determined by X-ray single-crystal diffraction analysis. (Ph4P)2[Pt(AS385)2] is a molecular cage compound with discrete [Pt(A8385)2]2' anions which are well separated from the organic cation, see Figure 4-1. There are two unique features in this compound: the most unusual [AS385]3' units and, remarkably, the presence of a Pt-AS bond. The [AS385]3' anion represents a new thioarsenic anion ‘and can be viewed as the two electron reduction product of a cyclic [AS385]3' unitlo, (see Eq. 4-1). This results in a negatively charged As atom in the [AS335]3‘ unit which bonds to Pt4+. The total charge of each ligand is 3-, with each of the sulfur atoms in a 2- oxidation state. We then can assign the formal oxidation states of the two AS atoms that are not connected to the metal center as 3+ while the Pt-bound arsenic is assigned 1+. However, it should be noted that despite the different oxidation states for the As atoms in the [AS385]3' units, there is no notable difference in the As-S bond distances which vary from 2.177(5)A to 2.291(5)A. 146 [11838513 + 26' ~ [A838513' + 8" (eq. 1) The Pt metal resides in a distorted octahedral environment coordinated by two [AS385]3' ligands through two 8 and one As atom respectively, see Figure 4-2. Although we started with Pt“, the geometry of the metal atom indicates it is now in the 4+ oxidation state suggestive that Pt is the reducing agent for [AS336]3'. There are only two other mononuclear Pt4+ polychalcogenide compounds, [Pt(85)3]2',3 and [Pt(84)(85)2)]2',ls known. The average Pt-S bond distance where the sulfur atom is trans to an As atom is 2.428(5)A, significantly longer than the other Pt-S bond distances at 2.355(5)A. The latter distances are within the normal range (2.332A to 2.479A) for Pt-S bond distances found in (Pt(84)3]2'. 3 The AS-S distances and S-As-S angles are normal based on those observed in previously characterized arsenic sulfur compounds.16 To the best of our ‘ knowledge and with the exception of solid state platinum arsenides, this is the first observation of a platinum-arsenide bond and it is surprising, particularly considering it formed in aqueous solution. Selected distances and angles are given in Tables 4.8-4.9. 147 Table 4.8. Selected Distances (A) in the [Pt(AS385)2]2' with Standard Deviations in Parentheses.a Pt - As(3) 2.453(2) Pt - As(5) 2.455(2) Pt - S(4) 2.430(5) Pt - S(5) 2.351(5) Pt - 8(9) 2.358(5) Pt - S(10) 2.425(5) As(l) - 8(1) 2.245(5) As(l) - 8(2) 2.285(7) ‘ As(l) - S(4) 2.177(5) As(2) - 8(2) 2.253(7) As(2) - S(3) 2.229(5) As(2) - S(5) 2.189(6) As(3) - S(l) 2.261(6) As(3) - S(3) 2.291(5) As(4) - 8(6) 2.214(6) As(4) - 8(7) 2.281(6) As(4) - S(9) 2.196(6) As(5) - 8(6) 2.277(5) As(5) - 8(8) 2.263(6) As(6) - 8(7) 2.282(6) As(6) - 8(8) 2.236(5) As(6) - S(10) 2.177(5) aThe estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01: [£n(ln - 1)2/n(n-l)}1/2, where In is the length (or angle) of the nth bond, 1 the mean length (or angle), and n the number of bonds. 148 Table 4.9. Selected Angles (Deg) in the [Pt(AS385)2]2‘ with Standard Deviations in Parentheses.a As(3)-Pt-As(5) 79.830) As(3)-pt-8(5) 100.5(1) As3-Pt-8(10) 171.9(1) As(S)-Pt-8(S) 81.9(1) As(S)-Pt-S(10) 97.7(1) S(4)-Pt-S(9) 87.6(2) S(5)-Pt-S(9) 177.9(2) 8(9)-Pt-8(10) 92.1(2) S(1)-Pt-S(4) 100.1(2) S(2)-Pt-S(3) 102.6(2) Pt-As(3)-S(1) 104.7(1) 8(1)-As(3)-S(3) 101.5(2) S(6)-As(4)-S(9) 101.3(2) Pt-As(5)-S(6) 103.5(1) S(6)-As(5)-S(8) 100.6(2) S(7)-As(6)-S(10) 107.1(2) As(1)-S(1)-AS(3) 106.5(2) AS(2)-S(3)-As(3) 105.9(2) Pt-S(5)-As(1) 108.7(2) AS(4)-S(7)-As(6) 114.9(2) Pt-8(8)-As(4) 109.0(2) As(3)-Pt-S(4) 98.3(1) As(3)-Pt-S(9) 80.9(1) As(5)-Pt-S(4) 171.8(1) A8(5)-Pt-S(9) 99.9(1) S(4)- Pt-S(5) 90.7(2) S(4)-Pt-S(10) 85.3(2) S(5)-Pt-S(10) 86.6(2) S(1)-Pt-S(2) 103.2(2) 8(2)-Pt-S(4) 107.7(2) S(3)-Pt-S(5) 102.4(2) Pt-As(3)-S(3) 103.8(1) 8(6)-As(4)-S(7) 105.8(2) S(7)-As(4)-S(9) 105.1(2) Pt-As(5)-S(8) 105.7(1) S(7)—As(6)-S(8) 103.8(2) S(8)~As(6)-S(10) 100.9(2) As(l)-8(2)-As(2) 115.8(2) Pt-S(4)-A8(l) 108.7(2) As(4)-S(5)-As(5) 106.2(2) As(S)-S(8)-As(6)106.5(2) Pt-S(9)-As(6) 109.0(2) 149 Figure 4-1. Packing diagram of (Ph4P)2[Pt(AS3Ss)21 150 A86 “\w 57 s. :1 8’ 810 Figure 4-2. Structure and labeling scheme of [PtASGS 1012'. 151 When the amount of A8833° is decreased, the above redox chemistry is avoided and the Pt2+ cluster (Ph4P)2K[Pt3(A884)3]-1.SH20 forms in very good yield while the Pd analog, (Ph4P)2K[Pd3(ASS4)3]-3MeOH(III), is synthesized by using the PdCl2/K3ASS3/Ph4PBr ratio of 1:2:6 in methanol at 110 °C for one day. The reaction gave bright-red rod-like crystals of (Ph4P)2K[Pd3(ASS4)3]-3MeOH in good yield. The structure of the anion [Pd3(AsS4)3]3' is the same as that of the Pt analog. The difference is that instead of being a hydrate it is a methylate with three CH3OH molecules in the formula unit. The structure of the anion is showed in Figure 4-5. The selected distances and angles is given in the Table 4-10 and 4-11. (Ph4P)2K[Pt3(AsS4)3] contains discrete trinuclear anions of [Pt3(AsS4)3]3', see Figure 4-3. The most unique feature of the compound is the presence of a new kind of [ASS4I3' ligands, which can be viewed as the oxidative coupling product between .[ASS3]3' and 82'; see eq. 2. This anion contains As(III) and it is different from the well known tetrahedral [A884]3' which is a As(V) species. The two isomers are related via an internal redox equilibrium according to eq. 3. [A883J3' + S" ‘ [A884I3' + 2e' (eq. 2) 152 . 2 3- r- -3- s A: —s \ )5 / \ was As (9“. 3) s s, s s/ \s Each [ASS4]3' ligand that binds to two Pt atoms employs all its terminal 8 atoms, see Figure 4-4. A close inspection of the structure reveals the close relationship between the polychalcogenide and the thioarsenate ligands. The structure of [Pt3(AsS4)3]3', can be viewed as three "[Pt(AsS3)2]" units fused together, see shceme 1. If the As atom in the A883 unit is thought an 8 atom then the "[Pt(AsS3)2]" becomes the known [Pt(84)2]2' which was recently synthesized, methanothermally, by Dr. Kang-Woo Kim in our lab.” As / \S /"‘°’\ S Scheme 1 The central cluster Pt3S3 core involving the atoms Pt(1), Pt(2), Pt(3). 8(1), 8(2), and 8(3) is in a distorted "cyclohexane-chair" 153 conformation forming a partial cube which derives from a hypothetical Pt484 cube by removing a S and a Pt atom lying on a body diagonal. Interestingly, a cluster with a Pt484 cubane core has recently been described.4 Each Pt atom is coordinated by four sulfur atoms in a distorted square planar fashion with bond angles ranging from 84.0 (1)° to 179.0(1)°. The formal oxidation state of the metal center is 2+. The Pt-S bond distances range from 2.285(6)A to 2.345(7)A, while the AS-S bond distances vary from 2.202(7)A to 2.254(7)A. Selected distances and angles are given in Tables 4.10- 4.11. 154 Table 4-10. Selected Distances (A) in the [M3(ASS4)3]3' (M = Pt, Pd) with Standard Deviations in Parentheses.a [PtngsSflgp’ [Pd3(A883)3]3' Pt(1) - S(3) 2.323(6) Pd(1) - S(3) 2.322(2) Pt(1) - S(2) 2.315(5) Pd(1) - S(2) 2.330(2) Pt(1) - 8(7) 2.362(7) Pd(1) - S(7) 2.331(2) Pt(1) - 8(6) 2.341(7) Pd(1) - 8(6) 2.318(2) Pt(2) - 8(1) 2.314(8) Pd(2) - 8(1) 2.332(2) Pt(2) — S(4) 2.353(6) Pd(2) - 8(4) 2.321(2) Pt(2) - S(2) 2.298(6) Pd(2) - S(2) 2.326(2) Pt(2) - S(10) 2.294(6) Pd(2) - S(10) 2.316(2) Pt(3) - S(3) 2.285(6) Pd(3) - S(3) 2.319(2) Pt(3) - S(ll) 2.292(7) Pd(3) - S(ll) 2.333(2) Pt(3) - 8(1) 2.324(5) Pd(3) - 8(1) 2.334(2) Pt(3) - S(5) 2.345(7) Pd(3) - S(5) 2.313(2) As(l) - 8(7) 2.215(7) As(l) - 8(7) 2.235(2) As(l) - S(5) 2.208(6) As(l) - S(5) 2.227(2) As(2) - 8(6) 2.202(7) As(2) - 8(6) 2.227(2) As(2) - S(4) 2.216(7) As(2) - S(4) 2.207(2) As(2) - 8(9) 2.232(6) As(2) - 8(9) 2.235(2) As(3) - S(11) 2.195(7) As(3) - S(ll) 2.232(3) As(3) - S(10) 2.246(7) As(3) - S(10) 2.207(2) As(3) - S(12) 2.264(7) As(3) - S(12) 2.216(3) 8(1) - S(12) 2.074(8) S(l) - S(12) 2.055(3) S(2) - S(9) 2.101(8) S(2) - 8(9) 2.091(3) S(3) - 8(8) 2.105(7) S(3) - 8(8) 2.079(3) aThe estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {21.0“ - l)2/n(n-1)]1/2, where 1,. is the length (or angle) of the nth bond, 1 the mean length (or angle), and n the number of bonds. 155 Table 4-11. Selected Angles (Deg) in the [M3(ASS4)3]3’ (M = Pt, Pd) with Standard Deviations in Parentheses.“ [Pt3(A883)3]3' S(2)-Pt(1)-S(3) 85.6(1) S(2)-Pt(1)-S(7) 174.2(1) S(3)-Pt(1)-S(7) 94.5(1) S(2)-Pt(1)-S(6) 94.8(1) S(3)-Pt(l)-S(6) 178.0(1) S(6)-Pt(l)-S(7) 84.8(1) S(1)-Pt(2)-S(2) 84.0(1) S(1)-Pt(2)-S(10) 95.5(1) S(2)-Pt(2)-S(10) 178.8(1) S(1)-Pt(2)-S(4) 178.6(1) S(2)-Pt(2)-S(4) 95.0(1) S(4)-Pt(2)-S(10) 85.5(1) S(1)-Pt(3)-S(3) 84.6(1) S(1)-Pt(3)-S(11) 94.4(1) S(3)-Pt(3)-S(11) 178.8(2) S(1)-Pt(3)-S(5) 179.0(1) S(3)-Pt(3)-S(5) 94.4(1) S(5)-Pt(3)-S(11) 86.6(2) S(5)-As(1)-S(7) 106.5(1) S(5)-As(l)-S(8) 96.4(2) S(7)-As(1)-S(8) 98.5(2) S(4)-As(2)-S(9) 97.5(2) S(4)-As(2)-S(6) 105.5(2) S(6)-As(2)-S(9) 98.0(2) S(10)-As(3)-Sll 104.3(2) S(ll)-As(3)-Slz 97.1(2) S(10)-As(3)-812 97.5(2) Pt(2)-S(l)-Pt(3) 93.5(4) Pt(2)-S(l)-S(12) 110.1(5) Pt(3)-S(1)-S(12) 109.7(5) Pt(1)-S(2)-Pt(2) 93.6(3) Pt(1)-S(2)-S(9) 109.5(6) [szSAsSflaP' S(2)-Pd(1)-S(3) 85.65(7) S(2)-Pd(l)-S(7) 177.50(7) S(3)-Pd(1)-S(7) 94.85(7) 8(2)-Pd(1)-S(6) 9S.11(7) S(3)-Pd(1)-S(6) 176.86(7) S(6)-Pd(1)-S(7) 84.S3(7) S(1)-Pd(2)-S(2) 84.29(7) S(1)-Pd(2)-8(10) 96.09(8) S(2)-Pd(2)-S(10) 178.77(9) S(1)-Pd(2)-S(4) 178.84(7) S(2)-Pd(2)-S(4) 96.67(7) S(4)-Pd(2)-S(10) 82.86(8) S(1)-Pd(3)-S(3) 85.00(7) S(1)-Pd(3)-S(11) 95.05(8) S(3)-Pd(3)-S(11)179.03(8) S(1)—Pd(3)-S(5) 176.77(7) S(3)-Pd(3)-S(5) 95.16(7) S(5)-Pd(3)-S(l l) 84.73(8) S(5)—As(1)-S(7) 104.38(8) S(5)-As(l)-S(8) 98.00(9) S(7)-As(1)—S(8) 97.02(8) S(4)-As(2)-S(9) 98.13(8) S(4)-As(2)-S(6) 105.87(8) S(6)-As(2)-S(9) 97.46(8) S(10)-As(3)-Sll 104.4(1) S(11)-A8(3)-812 99.8(1) S(10)-As(3)-812 99.1(1) Pd(2)-8(1)-Pt(3) 92.07(7) Pd(2)-S(1)-S(12) 108.0(1) Pd(3)-S(1)-8(12) 110.8(1) Pd(1)-S(2)-Pt(2) 92.00(7) Pd(1)-SQ)-SQ) 108.7(1) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {2n(ln - 1)2/n(n-1)}1/2, _where 1,, is the length (or angle) of the nth bond, 1 the mean length (or angle), and n the number of bonds. 156 n Figure 4-3. Packing diagram of (Ph4P)2K[Pt3(AsS4)3]. 157 Figure 4-4. Structure and labeling scheme of [Pt3(ASS4) 313'. 158 $10 Figure 4—5. Structure and labeling scheme of [Pd3(AsS4)3]3'. l 5 9 3.2 Physicochemical studies DMF solutions of (Ph4P)2[Pt(AS385)2] and (Ph4P)2K[Pt3(AsS4)3]-l.5H20 are orange and yellow, respectively, and give featureless UV/Vis spectra. The far-IR spectra of (Ph4P)2[Pt(AS385)2](I), (Ph4P)2K[Pt3(ASS4)3]-1.5H2O(II), and (Ph4P)2K[Pd3(AsS4)3]-3MeOH(III) (see Figure 4-6) basically Show three sets of absorptions. Observed absorption frequencies of all the complexes are given in Table 4-12. Absorptions in the range of 200- * 400 cm'1 could be attributed to either M-S or As-S vibration modes. Similar assignments have been made in the far-1R spectra of other known thioarsenic complexes.16 The additional low energy peaks, at 23lcm'1 and 203 cm'l, in (Ph4P)2[Pt(AS385)2] could be due to M-AS vibration modes. For comparsion, in the far-IR spectrum of (Ph3P)2Pt(84), the 315 and 326 cm'1 peaks were assigned to the Pt-S vibration modes.17 There is also a 8-8 vibration for (Ph4P)2K[Pt3(ASS4)3]-1.5H20 and (Ph4P)2K[Pd3(AsS4)3]-3MCOH at 448 cm“1 and 456 cm], respectively. In the previously characterized metal polysulfide complexes, the 8-8 vibration modes occur in the similar region. Some representative example are as follows: [Re4822]4' (465 cm'l),18 [Pd2823]4' (482 and 453 cm'l),19 [M(85)2]2'( M = Zn, Cd, Hg) (495 and 455 cm'l).20 160 TRANSMITTANCE (C) N 498 459 420 361 342 363 264 225 186 147 WAVENUMBER Figure 4-6. Far-1R spectral Data for (A) (Ph4P)2[Pt(AS3S5)2](I), (B) (Ph4P)2KIPt3(ASS4)3]-1.5 H2001), and (C) (Ph4P)2K1Pd3lASS4)31'3 MeOH(IlI). Table 4-12. 161 Far-IR spectral Data for (Ph4P)2[Pt(AS385)2](I), (Ph4P)2K[Pt3(ASS4)3]-1.5 H2O(II), and (Ph4P)2K[Pd3(AsS4)3]-3 MeOH(III). Compounds Infrared Raman 1 401(8). 388(m) 305(w). 337(m), 301(m) 369(8), 351(8) 288(w), 234(8), 182(m) 334(m), 298(w) 177(m), 160(w) 231(m), 203(w) II 449(w), 377(m) 383(w), 365(m), 336(m) 331(m, sh), 300(m) 318(8), 297(w), 284(w) 280(w), 194(w) 269(w), 236(8) 210(m), 185(m) III 456(w), 375(8) 391(w), 359(m) 336(m), 308(w) 284(m), 233(m, sh) 191(m) 307(8), 259(w) 208(w), 190(w) 176(w), 157(m) * 8: strong, m; medium, w: weak, sh: shoulder. FT-Raman spectra of (I), (II), and (III) were also collected. 1 There are a number of peaks in the range between 150 to 400 cm' . The specific assignments were difficult since these peaks can be assigned to either the As-S or M-S vibration modes. One interesting observation is that we did not see the S-S stretching mode (expected 162 around 480 cm-l) in either (Ph4P)2KlPt3(AsS4)31(II) or (Ph4P)2K1Pd3(A854)31(III) Thermal Gravimetric Analysis (TGA) results for all compounds are summarized in Table 4-13 and shown in Figure 4-7 and 4-8. Table 4-13. TGA Data for (Ph4P)2[Pt(AS385)2](I), (Ph4P)2K[Pt3(AsS4)3] - 1.5H2O(II), and (Ph4P)2K[Pd3(ASS4)3] - 3MeOH(III). Compound Temp. range (°C) Weight loss (%) (Ph4P)2[Pt(AS355)2] 120 - 550 56.1 (Ph4P)2K[Pt3(AsS4)3]-1.5H2O 90 - 155 2.0 330 - 500 45.5 580 - 800 13.5 (Ph4P)2K[Pd3(ASS4)3]-3MeOH SO - 125 3.0 326 - 530 47.5 570 - 800 12.8 (Ph4P)2[Pt(AS385)2] showed a one step weight loss of 56.1 % in the temperature range of 120 - 550 °C. The black residue obtained from the decomposition contains Pt, AS and 8 in the 2:1.5:1 ratio. There are no known phases with Pt/As/S. For (Ph4P)2K[Pt3(ASS4)3]-l.5H2O (II) the 2 % weight loss in the temperature range of 90 - 150 °C is due to the loss of the water molecule. The compound loses 45.5 % of its weight in the second step. For (Ph4P)2K[Pd3(AsS4)3]-3MeOH (III) the 3.0 % weight loss in the temperature 50 - 125 °C could be due to the loss of methanol 163 110 1 1 1 100- (A) ~ 90- r- 807 - 70- - W(%) 50- r- 0 200 400 600 800 W(%) V o 1 l T I O 200 400 600 800 Temp (°C) Figure 4-7. TGA diagrams of (A) (Ph4P)2[Pt(AS3SS)2](I), (B) (Ph4P)2KIPt3(AsS4)3]-1.5 H2001). 164 110 1 ‘ 100- ._ _. 90- - 70- - 60- - so- - W(96) 30 1 1 l 0 200 400 600 800 Temp (°C) Figure 2-9. TGA diagram of (Ph4P)2Kde3(AsS4)31°1.S 1120(111). 165 molecules. In the next step of weight 1088, (III) loses 47.5 % of its mass, as in the case of (II). In both (11) and (111), mass 1088 continues above 800 °C. The final residue for both (11) and (III), appears by SEM/EDS analysis, contains to K/Pt/As/S and K/Pd/As/S in the Similar 1:3:2:1.5 ratio. There are no known quaternary K/Pt/As/S phases. Three group 10 metal/Asty (Q = 8, Se) compounds have been synthesized through hydro(methano)thermal reactions. The most unexpected outcome of these reactions is the redox chemistry and the Pt-As bond formation. Attempts to prepare the Pd analog of the [PtA85810]2' anion were unsuccessful due to the fact that Pd4+ compounds are both thermodynamically and kinetically unstable. Similar to previous observations in metal polychalcogenide chemistry, cation size is very important in determining the type of clusters found in the product. These compounds have so far proven to be inaccessible by conventional solution reactions due to the fact that no common soluble thioarsenate source is available. It is , however, entirely possible that these types of clusters may be accessible if a suitable thioarsenate anion is used. The structure of [Pt3(AsS4)3]3‘ is of particular interest in that [Pt(S4)2]2'-like fragments can be recognized in the structure. Such fragments reinforce our previous statement that, conceptually, thioarsenic polyanions are similar to polysulfide ligands. With the introduction of the trivalent AS atoms the complexity of the product 166 will no doubt increase dramatically due to an increase in possible connectivity. In conclusion, the successful hydr0(solvo)thermal synthesis of (Ph4P)2[Pt(AS385)2](I), (Ph4P)2K[Pt3(AsS4)3]-1.5H20(II), and (Ph4P)2K[Pd3(AsS4)3]-3MeOH(III), indicates that not only polymeric solid state compounds, but also formation of large clusters is also possible in the metal/AsxSy system. The discovery of the new ligands, [A8385]3' and [ASS4]3', in these compounds suggests that in addition to the already complex condensation equilibria between the various [AsxSyP' species, redox reactions also exist in the reaction media. Therefore, the thioarsenate systems are much more complicated in nature than the pure polychalcogenide solutions. The three novel clusters reported here represent innovative extensions of the long known platinum/palladium polysulfide chemistry. That coupled with the observation of novel bonding, such as Pt-AS bond, justifies further investigations in this area of chemistry. The fact that familiar fragments can be recognized in the [Pt3(AsS4)3]3* make this chemistry even more exciting by virtue of the enormous structure types reported in the metal polychalcogenide chemistry. The introduction of a trivalent As atom in a polychalcogenide chain generates additional Structural complexity that is not possible with polychalcogenides only. This forecasts the development of exciting new higher-order clusters and solid state chemistry with thioarsenates. 167 REFERENCES (a) Hartley, F. R. The Chemistry of Platinum and Palladium, Applied Science Publishers, London, UK, 1973. b) Belluco, U. Organometallic and Coordination Chemistry of Platinum, Academic Press, London, UK, 1974. (a) Roundhill, D. M. Comprensive Coordination Chemistry Vol.5 351-531, Pergamon Press, London, UK, 1987. (b) Troitskaya, A. D. Shmakova, E. L. Russ. J. Inorg. Chem. (Engl. Transl.) 1971, 16, 872. (a) Jones, P. B.; Katz, L. J. Chem. Soc. Chem. Commun. 1967, 779- 783. (b) Schmidt, M. Angew. Chem. Int. Ed. Engl. 1973, 12, 445-455. (c) Spangenberg, M. Bronger, W. Z. Naturforsch. 1978, 330, ”482-484. Kim, K.-W., Kanatzidis, M. G. Inorg. Chem. 1993,32, 4161-4163. Ansari, M. A.; Ibers, J. A. Inorg. Chem. 1989, 28, 4068-4069. (a) Sheldrick, W. 8. Z. Anorg. Allg. Chem. 1988, 562, 23-30. (b) Sheldrick, W. 8.; Hauser, H.-J. Z. Anorg. Allg. Chem. 1988, 55 7, 98-104. (0) Sheldrick, W. 8.; Braunbeck, H. G. Z. Naturforsch. 1989, 44b. 851-852. (d) Parise, J. B. Science 1991, 251, 293- 294. (e) Parise, J. B. J. Chem. Soc., Chem. Commun. 1990, 1553- 1554. 10. 11. 12. 13. 14. 1 6 8 (a) Liao, J.-H.: Kanatzidis, M. G. J. Am. Chem. Soc. 1990, 112, 7400-7402. (b) Liao, J.-H.; Kanatzidis, M. G. Inorg. Chem. 1992, 31, 431-439. (0) Kim, K.-W. Kanatzidis, M. G. J. Am. Chem. Soc. 1992, 114, 4878-4883. (d) Dinhgra, 8.; Kanatzidis, M. G. ‘ Science, 1992,258, 1769-1772. (e) Kim, K.-W.; Kanatzidis, M. G. J. Am. Chem. Soc.1993, 115, 5871-5872. (a) Soghomonian, V.; Chen, Q.; Haushalter R. C.; Zubieta, J.; O'Connor, C. J. Science, 1993, 259, 1596-1599. (b) Soghomonian, V.; Chen, Q.; Haushalter R. C.; Zubieta, J. Inorg. Chem. 1994,33, 1700-1704. (0) Warren, C. J.; Dhingra, S. 8.; Ho, D. M.; Haushalter R. C.; Bocarsly, A. B. Inorg. Chem. 1994, 33, 2704-2711. (d) Khan. M. 1.; Lee, Y.-S.; O'Connor, C. J.; Haushalter R. C.; Zubieta, J. Inorg. Chem. 1994, 33, 3855-3856. Chou, J.-H.: Kanatzidis, M. G. Inorg. Chem. 1994,33, 1001-1002. Sheldrick, W. 8.; Kaub, J. Z. Naturforsch. 1985, 401), 19-21. Sheldrick, G. M. In Crystallographic Computing 3; Sheldrick, G. M.; Kruger, C.; Goddard, R., Eds.; Oxford University Press: Oxford, U.K., 1985; PP 175-189. TEXSAN: Single Crystal Structure Analysis Package, Version 5.0, Molecular Structure Corp., Woodland, TX. Walker, N.; Stuart, D. Acta Crystallogr. 1983,39A, 158-166. (a) Sheldrick, W. J.; Kaub, J. Z. Naturforsch. 1985, 40b, 1130- 1133. (b) Porter, E. J.; Sheldrick, G. M. J. Chem. Soc. Dalton. 15. 16. 17. 18. 19. 20. 1 6 9 Trans. 1971, 3130-3134. (c) Zank, G. A.; Rauchfuss, T. B.; Wilson, 8. R. J. Am. Chem. Soc. 1984, 106, 7621-7623. CERIUS: Single Crystal Structure Analysis Software, Version 5.0, Molecular Simulations Inc. Cambridge, UK. (a) Mohammed, A.; Miiller, U. Z. Anorg. Allg. Chem. 1985.523, 45-53. (b) Sinning, H.; Miiller, U. Z. Anorg. Allg. Chem. 1988, 564, 37-44. Wiess, J. Z. Anorg. Allg. Chem. 1986,542, 137-143. Miiller, A.; Krickemeyer, B.; B0gge, H. Angew. Chem. Int. Ed. Engl. 1986, 25, 272-272. Miiller, A.; Schmitz, K.; Krickemeyer, B.; Bfigge, H. Angew. Chem. Int. Ed. Engl. 1986,25, 453-454. Miiller, A.; Schimanski, J.; Schimanski, U.; B0gge, H. Z. Naturforsch. 1985, 40b, 1277-1288. 170 CHAPTER 5 HYDROTHERMAL SYNTHESIS OF M/AstY (M = Hg“, Q = S, Se) COMPOUNDS. SYNTHESIS AND CHARACTERIZATION OF (Ph4P)2[H82AS4S9KDr (Me4N)[HSASSS6](H). (Me4N)[HgAsSe3](III), (Et4N)[I-IgASSe3](IV), and (Ph4P)2[lingS4Selll(V). 171 ABSTRACT (Ph4P)2[ngAS4S9] (1). (M94N)[H8AS3S6] (II). (MC4N)[H8ASSC31 (III), (Et4N)[HgAsSe3] (IV), and (Ph4P)2[Hg2AS4Se11] (V) were synthesized hydrothermally by using mixtures of HgCl2/2K3A883/2Ph4PBr(Me4NCl), HgC12/3K3AsSe3/4Me4NCl(Et4NBr, Ph4PBr), respectively, in sealed Pyrex tubes. The structures were determined by single-crystal X-ray diffraction analysis. (Ph4P)2[Hg2AS489] crystallizes in the monoclinic space group P21/c .(No. 14) with a = 10.119(2)A, b = 18.010(4)A, c = 14.932(3)A, fl: 103.98(2)°,Z = 4, V = 2640(2)A3. [Hg2AS489],.2"' has a one- dimensional polymeric chain structure consisting of trigonal planar Hg“ and linear [AS489]5' units formed by corner sharing [ASS3]3' units. (Me4N)[HgAS385] crystallizes in the monoclinic space group C2/c (No. 15) with a = 18.607(7)A, b = 7.126(1)A, c = 26.524(6), 13: 91.87(2)°,Z = 8, V = 3515(3)A3. The anionic [I-IgAS385],."‘ possesses a two-dimensional layered structure with distorted tetrahedral Hg2+ and corner sharing A8833“ units. The Me4N+ cations are located between the layers. The interlayer distance is 9.303A. (Me4N)[HgAsSe3] and (Et4N)[HgASSe3] both crystallize in the monoclinic Space group P21/n (No. 14) with a = 7.115(1)A, b = l7.464(5)A, c = 9.356(2)A, p: 91.34(1)o,z = 4, V = 1162.2(7)A3 for the former and a = 7.175(2)A, b = 18.907(4)A, c = 10.897(3)A, fl: 99.S6(2)°,Z = 4, V = 1457(1)A3 for the latter. They have the same one-dimensional chain-like anionic framework with trigonal planar Hg“ and [AsSe3]3' units. (Ph4P)2[Hg2AS4Se11] crystallizes in the triclinic space group P-l (No. 2) with a = 10.329(2)A, b = 17.017(3)A, 172 c = l7.485(3)A, a = 9270(1), )3: 105.73(1)o, y = 103.7l(1), z = 2, v = 2853(1)A3. [I-Ig2AS4Se11],.2"' also possess a one-dimensional chain- like structure consisting of both trigonal-planar and. tetrahedral Hg2+ ions. It too contains a unique [AS43611]6' ligand which binds to four H g2+ ions. The solid State optical and infrared spectra of these compounds are reported. 173 1. Introduction Recently, research carried out in this group and others has shown that the hydro(solvo)thermal technique is a useful synthetic tool toward the synthesis of novel transition and main group metal polychalcogenides that are often inaccessible by traditional solution methods.“3 Parise and co-workers also adopted this methodology to investigate the beSy system and have reported some very interesting results.4 We have extended this chemistry to explore the possibility of applying the hydrothermal technique to systems containing metal atoms, [AsS3]3' and organic counterions R4E+ (E = P, R = Ph; E = N, R = alkyl) and have successfully synthesized several new metal thioarsenate compounds, including [InAS3S7]2', [BiA86812]3',5 [SnAS48912'. [NiAS43812'r [M0202A‘\1‘>2S712'.6 [Pt(A8355)2]2'. [Pt3(AsS4)3l3' .7 The structures of these compounds range from molecular to one- dimensional chains to two-dimensional layers. In these compounds the [ASS3]3’ anion shows a facile condensation ability that results in higher nuclearity [AsxSy]n'_ units which are found coordinated to the metal cations. Here we will explore if this chemistry can be extended to the Hg/Asty (Q = 8, Se) systems. In this chapter, we describe the synthesis and characterization of five new compounds, (Ph4P)2[ngAS4S91(I). (Me4N)[HgAS3S6](II). (M94N)[H8ASSC3](III). (Et4N)[HgA8393KIV). and (Ph4P)2[H82AS4Selll(V)- 174 2. Experimental Section 2.1. Reagents Chemicals in this work, other than solvents, were used as obtained: (i) selenium powder, ~ 100 mesh, 99.5% purity, Mercury chloride, HgClz, 99.5% purity, tetraphenylphosphonium bromide, Ph4PBr, 99% purity, tetramethylammonium chloride, Me4NCl, 99% purity, tetraethylammonium bromide, Et4NBr, 99% purity, Aldrich Chemical Company, Inc., Milwaukee, WI; (ii) arsenic sulfide, A8283, 100 mesh, 99% purity, arsenic selenide, AS2Se3, 200 mesh, 99% purity, Cerac Inc. Milwaukee WI; (iii) potassium metal, analytical reagent, Mallinckrodt Inc., Paris, KY; (iv) Methanol, anhydrous, Mallinckrodt Inc., Paris, KY; diethyl ether, AC8 anhydrous, EM Science, Inc., Gibbstown, NJ. 2.2. Physical Measurements for details see chapter 2. 2.3. Synthesis All syntheses were carried out under a dry nitrogen atmosphere in a vacuum atmosphere Dri-Lab glovebox except were specifically mentioned. K3ASS3 (K3AsSe3) was synthesized by using stoichiometric amounts of alkali metal, arsenic sulfide(selenide), and sulfur(selenium) in liquid ammonia. The reaction gives a yellow (orange) brown powder upon evaporation of ammonia. , 175 (Ph4P)2[Hg2A84Sg](I): A Pyrex tube (.. 4 mL) containing HgCl2 (0.087 g, 0.5 mmol), K3ASS3 (0.144 g, 0.5 mmol), Ph4PBr (0.419 g, 1 mmol) and 0.3 mL of water was sealed under vacuum and kept at 130 °C for one week. The large pale yellow transparent rod-like crystals that formed were isolated in MeOH and washed with ether. (Yield = 84.5%, based on Hg) Semiquantitative microprobe analysis of several single crystals gave P:Hg:As:8 = 1:1.2:1:7. (Me4N)[HgAS386](II): A mixture of HgCl2 (0.087 g, 0.5 mmol), K3A883 (0.144 g, 0.5 mmol) and Me4NCl (0.110 g, 1 mmol) was sealed under vacuum with 0.3-0.5 mL of water in a Pyrex tube(4 mL). The reaction was run at 130 °C for one week. The large pale yellow transparent crystals were isolated in 1120 and washed with methanol and diethyl ether. (Yield = 75.7 % based on Hg) Semiquantitative microprobe analysis of several single crystals gave Hg:As:S - 1:3:9. The presence of tetramethylammonium cations was confirmed by i n frared Spec trosc'opy. (Me4N)[HgAsSe3](III): An amount of 0.03 g (0.1 mmol) H gC12, 0.13 g (0.3 mmol) K3A88e3, 0.07 g (0.6 mmol) Me4NCl were thoroughly mixed and sealed in a thick-wall Pyrex tube with 0.3 mL of H20. The reaction was run at 110 °C for 2 days. The products were isolated by dissolving the excess starting material and KC] with H 20 and methanol and then washing with anhydrous ether to give 0-05 g of yellow rod-like crystals (55 % yield based on Hg). Semi- q uantitative microprobe analysis on single crystals gives H g 1A81,2Se3,3 as its formula. The presence of the 176 tetramethylammonium cations was confirmed by infrared spectroscopy. (Et4N)[HgAsSe3](IV): An amount of 0.03 g (0.1 mmol) HgCl2, 0.13 g (0.3 mmol) K3A88e3, 0.13 g (0.6 mmol) Et4NBr were thoroughly mixed and sealed in a thick-wall Pyrex tube with 0.3 mL of H20. The reaction was run at 110 °C for 2 days. The products were isolated as above to give 0.065 g of yellow-orange rod-like crystals (yield = 55 % based on Hg) Semi-quantitative microprobe analysis of several single crystals gives as the formula Hg1A81,2Se3,3. The presence of the tetraethylammonium cations was confirmed by infrared spectroscopy. (Ph4P)2[Hg2A848e11](V): An amount of 0.03 g (0.1 mmol) HgCl2, 0.14 g (0.3 mmol) K3A88e3, 0.24 g (0.6 mmol) Ph4PBr were thoroughly mixed and sealed in a thick-wall Pyrex tube with 0.5 mL of H20. The reaction was run at 110 °C for one week. The dark-red chunky crystal were isolated as above.(0.076 g Yield = 76 %, based on Hg). Semi-quantitative microprobe analysis of several single crystals gives as the formula P1Hg1AS2,3Se7,3. 2.4 X-ray crystallography (Ph4P)2[Hg2AS489](I): Single-crystal X—ray diffraction data were collected on a P3 Nicolet four-circle diffractometer by using the (tn-20 scan mode and graphite monochromated Mo Ka radiation at -- 100 °C. During the structure refinement, we found the position of the 85 atom very close to the special position (1/2, 1, 1). However, fixing the SS atom in (1/2, 1, 1) resulted in an increased temperature 177 factor, with the A82-SS bond distance becoming too short. A better refinement as well as a more reasonable As-S distance was obtained if the SS atom was displaced away from the special position. The SS atom was finally refined with 0.5 occupancy. The A82 and the 84 atoms were also found to be disordered between two sites, as a result of the SS deviation, and the occupancy of the two sites were refined to be 0.47 and 0.53 respectively. The positions of all hydrogen atoms were calculated by using a C-H distance of 0.96A. The scattering contribution of the hydrogen atoms was included in the structure factor calculation; but their positions were not refined. (Me4N)[HgAS386](II): Single-crystal X—ray diffraction data were collected at -100 °C on a Rigaku AFC6 diffractometer (Mo K01 radiation) by using the 01-20 scan mode. (Me4N)[HgAsSe3](III): Single-crystal X-ray diffraction data were collected with a Nicolet P3 four-circle automated diffractometer with a graphite-crystal monochromater at -100 °C. The data were collected by the 0—20 scan technique. (Et4N)[HgAsSe3](IV): Single-crystal X—ray diffraction data were collected with a Nicolet P3 four-circle automated diffractometer with a graphite-crystal monochromater at -100 °C. The data were collected by the 0—29 scan technique. (Ph4P)2[Hg2AS4Se11](V): The same procedure described above was used.. 178 None of the crystals showed any significant intensity decay as judged by three check reflections measured every 150 reflections throughout the data collection. The space groups were determined from systematic absences and intensity statistics. The structures were solved by using the direct method technique of SHELXS-869 and refined by the full-matrix least-squares techniques of the TEXSANlo software package of crystallographic programs. An empirical absorption correction based on til-scans was applied to each data set, followed by a DIFABS11 correction to the isotropically refined structure. All non-hydrogen atoms except nitrogen and carbon were refined anisotropically. All calculations were performed on a VAXstation 3100 Model 76 computer. The complete data collection parameters and details of the structure solutions and refinements are given in Tables 5-1 and 5-2. The fractional atomic coordinates, average temperature factors and their estimated standard deviations are given in Tables 5-3, 4, 5, 6, 7. 179 Table 5-1. Crystallographic Data for (Ph4P)2[Hg2AS489](I), (Mc4N)[HgAsasol(II) I I I Formula C43H40P2Hg2A8489 C4H12NHgA8385 F. w. 1666.89 691.37 a, A 10.1 19(2) 18.6070) b, A 18.010(3) 7.126(1) c, A 14.9320) 26.524(6) 01, deg. 90.00 90.00 13. deg. 103.98(2) 91.87(2) 7, deg. 90.00 90.00 2, v, A3 4, 2640(2) 8, 3515(2) Space Group color, habit Dcalc. g/cm3 Radiation 11, cm'1 291111111. deg. Absorption Correction Transmission Factors Index ranges No. of Data coll. Unique reflections P21/n (No. 14) pale yellow, plate 2.01 Mo K01 180.27 45.0 111 scan 0.14-1.00 05hglL05ksZQ -17 $15 17 4148 3624 C2/c (No. 15) pale yellow, plate 2.62 M0 K01 150.14 45.0 111 scan 0.16-l.00 0_<_h522,0$ks8. -30 51$ 30 3567 3362 180 Data Used 2028 1820 (Fo2 > 39(Fo2)) No. of Variables 13 3 1 16 Final R“/wa. % 5.8/4.7 7.2/9.3 “ R= 2(lF0l-chl)/2|F0I, b Rw=[2w(lFol-chl)2/ZwlFo|2}1’2 181 Table 5-2. Crystallographic Data for (Me4N) [H g A s S e 3 ](III) , (Et4N)[HgA8593KIV). and (Ph4P)2[H82AS4Scn)l(V) III IV v Formula C4HIZNHgAsSe3 CgHzoNHgAsSe3 C43H40P2Hg2AS4 Sell F. w. 586.40 642.40 2247.45 a, A 7.115(1) 7.175(2) 10.329(2) b, A 17.464(5) 18.907(4) 17.017(3) c,A 9.356(2) 10.897(3) l7.485(3) 01, deg. 90.00 90.00 92.70(1) 13, deg. 9134(1) 9956(2) 105.730) 7. deg. 90.00 90.00 103.710) z,v,A3 4, 1162.2(7) 4, 1457(1) 2, 2853(1) Space Group P2l/n(No 14) P21/n(No.14) P-l (No. 2) color, habit yellow, block yellow, block red, block Dc... g/cm3 3.35 2.93 2.62 Radiation Mo K01 Mo K01 Mo K01 ll.cm'1 253.12 201.93 147.06 20...“, deg. 45.00 45.00 45.00 Absorption lit scan 11! scan \y scan Correction Transmission 0.15-1.00 0.14-1.00 0.15-1.00 Factors Index ranges No. of Data coll. Unique reflections Data Used (Fo2 > 306102)) 05h58 05k519 -115l511 1785 1161 772 No. of Variables 66 Final R“/wa, % 3.5/2.6 a R: 2(lF0I-IFc|)/£|Fol, b Rw=[Zw(|Fol-chl)2/2w|Fol2} 1’2 182 05h58 05k521 -125l512 2222 1991 1574 82 3.0/3.1 -12 5h 512, 05k519 -195l519 8126 4277 4277 364 6.7/7.1 183 Table 5-3. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[Hg2As489] atorn x 1’ 2 32934142) Hgl 1.09698(1) 0.91918(7) 0.94178(7) 214(4) Asl 0.7588(2) 0.9214(2) 0.9457(2) 1.8(1) As2 0.4474(5) 0.9172(4) 0.9665(6) 1.6(3) As213 0.4819(5) 0.9018(3) 1.0356(6) 2.0(6) s1 0.6242(6) 0.8317(4) 0.9861(5) 3.3(3) 82 0.8856(6) 0.8478(4) 0.8794(4) 2.7(3) s3 1.0965(7) 1.0543(3) 0.9155(4) 2.7(3) S4 0.295(1) 0.836(1) 0.911(2) 3.1(5) S4B 1.308(1) 0.858(1) 1.033(1) 2.6(5) ss 0.547(1) 1.0060(8) 1.0739(9) 3.0(1) Pl 0.2239(6) 0.0809(4) 0.4147(4) 2.3(3) C1 0.359(2) 0.132(1) 0.386(1) 1.8(5) C2 0.412(2) 0.111(1) 0.310(1) 1.6(4) C3 0.503(2) 0.157(1) 0.285(2) 3.1(6) C4 0.541(2) 0.224(1) 0.329(2) 2.3(5) C5 0.500(2) 0.242(1) 0.406(2) 2.5(5) C6 0.408(2) 0.197(1) 0.431(1) 1.9(5) C7 0.069(2) 0.121(1) 0.351(1) 1.6(5) C8 0.066(2) 0.195(1) 0.334(2) 2.4(5) C9 0.055(2) 0.227(1) 0.284(2) 3.5(6) C10 0.172(3) 0.182(2) 0.242(2) 4.2(6) C11 -O.165(3) 0.108(2) 0.265(2) 3.7(6) 184 C12 -0.046(2) 0.079(2) 0.319(1) 2.6(5) C13 0.227(2) -0.013(1) 0.382(1) 1.5(4) C14 0.255(2) -0.07l(2) ).449(2) 3.0(5) C15 0.257(3) -0.145(2) 0.417(2) 4.5(7) C16 0.233(3) -0.l64(2) 0.324(2) 4.0(6) C17 0.205(2) -0.102(2) 0.255(2) 3.8(6) C18 0.200(2) -0.031(1) 0.289(1) 2.1(5) C19 0.239(2) 0.087(1) 0.535(1) 2.5(5) C20 0.130(2) 0.115(1) 0.568(2) 3.1(6) C21 0.144(2) 0.119(1) 0.663(2) 3.1(6) C22 0.260(2) 0.096(1) 0.725(2) 3.2(6) C23 0.369(2) 0.072(2) 0.693(2) 3.5(5) C24 0.359(2) 0.067(2) 0.596(2) 3.8(6) 1' ch=(4/3)[a2811 + 62822 +c2B33 + ab(cosy)812 + ac(cosB)Blg + bc(cosa)Bz3] 185 Table 5-4. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Me4N)[HgAS3Se6] atom X Y Z M, (A2) Hg 0.76646(7) 1.0918(2) 0.55382(6) 1.77(5) Asl 0.7375(2) 0.0086(5) 0.6852(1) 1.4(1) A82 0.7929(2) 0.6042(4) 0.5675(1) 1.3(1) A83 0.7899(2) 0.4780(4) 0.6916(1) 1.3(1) 8] 0.8404(4) 0.377(1) 0.5208(3) 1.3(1) 82 0.8427(4) 0.621(1) 0.7601(3) 2.0(4) S3 0.6861(5) 0.166(1) 0.6221(3) 2.0(4) S4 0.8352(4) 0.184(1) 0.7058(4) 2.2(4) SS 0.8468(5) 0.839(1) 0.5305(3) 1.6(3) S6 0.8693(4) 0.599(1) 0.6385(3) 1.8(3) N 0.037(2) 0.130(6) 0.627(2) 6(1) C1 0.016(6) -0.04(2) 0.651(5) 17(1) C2 -0.011(6) 0.20(1) 0.590(5) 16(1) C3 0.110(4) 0.134(9) 0.607(30 2(1) C4 0.034(4) 0.30(1) 0.670(4) 11(1) a B¢q=(4/3)[a2811 + b2B22 +c2B33 + ab(cos7)B12 + ac(cosB)B13 + bc(cos01)823] Table 5-5. Selected Atomic Coordinates and Estimated Standard 186 Deviations (esd's) of (Me4N)[HgAsSe3] atom X Y Z B29 3. (A2) Hg 0.13217(9) 0.95396(6) 0.1684(1) l.27(4) As -0.3584(2) 0.9499(1) ' 0.1158(2) 1.1(1) 86(1) 0.4031(2) 0.8567(1) 0.1456(2) 1.3(1) 86(2) -0.1535(2) 0.9060(1) 0.3058(2) 1.3(1) 86(3) -0.l813(2) 0.9077(1) ~0.0860(2) 1.3(1) N 0.633(2) 0.167(1) 0.389(2) 1.1(3) C(l) 0.583(2) 0.087(2) 0.428(3) 2.8(4) C(2) 0.678(2) 0.171(2) 0.243(3) 2.7(5) C(3) 0.470(2) 0.217(1) 0.415(3) 2.5(4) C(4) 0.790(3) 0.193(2) 0.481(3) 3.0(5) a B¢q=(4/3)[a2B11 + b2322 +czB33 + ab(cosy)B12 + ac(cosB)Bl3 + bc(cosa)B 23] 187 Table 5-6. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Et4N)[HgAsSe3] atom X Y Z Big a. (A2) Hg 0.15460(6) 0.53578(2) 0.14957(5) 0.84(2) As -0.3457(1) 0.53887(6) 0.1045(1) 054(4) 56(1) 0.4274(2) 0.62365(6) 0.1415(1) 092(5) Se(2) 0.2009(2) 0.41131(6) 0.0591(1) 077(5) Se(3) -o.1051(2) 0.56705(6) 0.2776(1) 0.76(5) N 0.239(1) 0.1731(5) 0.831(1) 0.9(2) C(1) 0.252(2) 0.1645(6) 0.695(1) 1.0(2) C(2) 0.136(1) 0.1077(6) 0.868(1) 0.8(2) C(3) 0.438(2) 0.1790(6) 0.911(1) 1.1(2) C(4) 0.137(2) 0.2410(6) 0.854(1) 0.7(2) C(5) 0.344(2) 0.2260(6) 0.640(1) 1.6(2) C(6) 0.107(2) 0.1047(7) 1.000(1) 2.2(3) C(7) 0.572(2) 0.1196(6) 0.899(1) 1.4(2) C(8) -0.064(2) 0.2447(7) 0.787(1) 2.0(3) a B¢q=(4/3)[a2B11 + b2822 +cZB33 + ab(cosy)Blz + ac(cosB)B13 + bc(cosa)Bz3] 188 Table 5-7. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of (Ph4P)2[Hg2AS4Se11] atom X Y Z Bfl:(A2) Hg(l) 0.2290(1) 0.13758(8) 0.36837(8) 230(5) Hg(2) 0.2230(1) 0.33493(9) 0.24541(9) 3.09(6) As(l) -0.088l(3) 0.2007(2) 0.3865(2) 2.0(1) As(2) -0.1573(3) 0.3269(2) 0.2369(2) 1.8(1) As(3) 0.5554(3) 0.1267(2) 0.3187(2) 2.5(1) As(4) 0.4518(3) 0.2530(2) 0.1624(2) 2.5(1) Se(1) 0.1818(3) 0.1233(2) 0.2111(2) 2.4(1) Se(2) 0.4725(3) 0.1135(2) 0.4292(2) 2.2( 1) Se(3) 0.0100(3) 0.0924(2) 0.4149(2) 2.6(1) 36(4) 0.0109(3) 0.3891(2) 0.1748(2) 2.0(1) Se(5) 0.3794(4) 0.3727(2) 0.1525(2) 4.0(2) Se(6) 0.2872(3) 0.3090(2) 0.3911(2) 2.0(1) Se(7) -0.1121(3) 0.1940(2) 0.2469(2) 2.3(1) 36(8) -0.3453(3) 0.2963(2) 0.1153(2) 2.7(1) Se(9) 0.3617(3) 0.0595(2) 0.2071(2) 2.9(1) Se(10) 0.0973(3) 0.3249(2) 0.4349(2) 2.5(1) 36(11) 0.5528(3) 0.2670(2) 0.3049(2) 2.4(1) 9(1) 0.5671(7) 0.3389(4) 0.6809(4) 1.4(3) P(2) 0.1153(7) 0.1936(4) 0.8649(4) 1.4(4) C(1) 0.700(2) 0.364(2) 0.632(2) 1.3(5) C(2) 0.677(3) 0.321(2) 0.555(2) 1.5(2) C(3) 0.778(3) 0.346(2) 0.518(2) 2.1(6) C(4) 0.899(3) 0.412(2) 0.549(2) 1.7(5) C(5) C(6) C(7) C(8) C(9) C(10) ca 1) C(12) . C(13) C(14) C(15) C(16) C(17) C(18) C(19) C(20) C(21) C(22) C(23) C(24) C(25) C(26) C(27) C(28) C(29) C(30) C(31) 0.914(3) 0.815(3) 0.457(3) 0.448(3) 0.360(3) 0.285(3) 0.293(3) 0.379(3) 0.645(3) 0.703(3) 0.772(3) 0.776(3) 0.716(3) 0.649(3) 0.478(3) 0.549(3) 0.475(3) 0.334(3) 0.258(3) 0.326(3) 0.250(3) 0.335(3) 0.442(3) 0.460(3) 0.373(3) 0.269(3) 0.012(2) 189 0.453(2) 0.430(2) 0.407(2) 0.448(2) 0.500(2) 0.513(2) 0.472(2) 0.419(2) 0.350(2) 0.432(2) 0.439(2) 0.373(2) 0.296(2) 0.282(2) 0.232(2) 0.178(2) 0.095(2) 0.074(2) 0.130(2) 0.213(2) 0.138(3) 0.138(2) - 0.101(2) 0.058(2) 0.055(2) 0.093(2) 0.160(2) 0.623(2) 0.664(2) 0.660(2) 0.593(2) 0.577(2) 0.632(2) 0.696(2) 0.710(2) 0.786(2) 0.826(2) 0.907(2) 0.949(2) 0.909(2) 0.832(2) 0.649(2) 0.652(2) 0.630(2) 0.613(2) 0.607(2) 0.627(2) 0.878(2) 0.956(2) 0.968(2) 0.900(2) 0.826(2) 0.814(2) 0.932(2) 2.2(6) 2.3(6) 1.6(5) 2.3(6) 3.0(7) 2.4(6) 3.4(7) 3.2(7) 1.6(5) 1.9(6) 2.8(6) 2.6(6) 3.5(7) 2.0(6) 1.8(6) 1.8(6) 3.4(7) 2.4(6) 2.7(6) 2.3(6) 2.1(6) 1.9(6) 2.5(6) 3.9(8) 3.1(7) 3.0(7) 1.4(5) 190 C(32) 0.005(2) 0.215(2) 0.992(2) 1.5(5) C(33) 0.075(3) 0.186(2) 1.040(2) 2.2(6) C(34) 0.141(3) 0.106(2) 1.037(2) 1.9(6) C(35) -O.126(3) 0.050(2) 0.979(2) 3.4(7) C(36) 0.050(3) 0.079(2) 0.925(2) 2.9(7) C(37) 0.193(2) 0.302(1) 0.889(1) 0.7(5) C(38) 0.108(3) 0.354(2) 0.877(2) 2.3(6) C(39) 0.167(3) 0.437(2) 0.888(2) 3.7(7) C(40) 0.310(3) 0.468(2) 0.910(2) 3.4(7) C(41) 0.401(3) 0.420(2) 0.922(2) 2.7(6) C(42) 0.335(3) 0.333(2) 0.909(2) 2.7(6) C(43) 0.016(3) 0.177(2) 0.763(2) 1.7(5) C(44) 0.042(3) 0.232(2) 0.709(2) .19(6) C(45) -0.028(3) 0.219(2) 0.632(2) 2.9(7) C(46) 0.134(3) 0.150(2) 0.598(2) 2.9(7) C(47) -0.l63(3) 0.096(2) 0.651(2) 2.2(6) C(48) -0.093(3) 0.107(2) 0.730(2) 3.1(7) a ch=(4/3)[a2811 + b2B22 +c2B33 + ab(cosy)Blz + ac(cosB)Bl3 + bc(cosa)Bz3] 191 The compounds were examined by X-ray powder diffraction for the purpose of phase purity and identification. Accurate dhkl spacings (A) were obtained from the powder patterns recorded on a calibrated (with FeOCl as internal standard) Phillips XRG-3000 computer-controlled powder diffractometer with graphite- monochromated Cu K01 radiation operating at 35 kV and 35 mA. The data were collected at a rate of 0.12°lmin. Based on the atomic coordinates obtained from the X-ray single crystal diffraction studies, X-ray powder patterns for all compounds were calculated by the software package CERIUS.11 Calculated and observed X-ray powder patterns that show d-spacings and intensities of strong hkl reflections are complied in tables 5-8 to 5-12. 192 Table 5-8. Calculated and Observed X—ray Powder Diffraction Pattern of (Ph4P)2[ngAS4S9](I)- h k z mull) dam-(A) I/Mbs. %) 0 1 1 11.29 11.28 100 0 2 0 9.00 9.00 14 0 2 0 8.21 8.21 7 0 0 2 7.24 7.23 26 0 2 2 5.64 5.64 6 0 1 3 4 66 4.66 14 0 4 0 4.50 4.50 9 2 1 1 4.22 0 5 1 3.49 3 0 -3 3.07 3 4 0 2.647 2.64 5 193 Table 5-9. Calculated and Observed X-ray Powder Diffraction Pattern of (Me4N)[HgAS3S(5](II). h k I dmLL(A) (1m (A) Illmobs. %) 0 0 13.2 13.2 7 2 0 0 9.298 9.29 100 2 0 -2 7.73 7.72 10 1 1 -1 6.47 2 0 4 5.48 5.48 7 4 0 0 4.65 4.64 8 4 0 -2 4.43 4.42 7 3 1 2 4.37 4.36 10 0 2 1 3.53 2 2 0 3.32 2 0 8 3 08 3.08 10 4 0 8 2.65 194 Table 5-10. Calculated and Observed X-ray Powder Diffraction Pattern of (Me4N)[HgAsSe3](III). h k I M (A) am (A) I/Imobs, %) 0 2 0 8.73 8.73 85 0 1 8.24 8.23 100 1 1 0 6.58 6.58 12 0 2 1 6.38 6.37 58 1 0 -1 5.72 5.72 10 1 2 -1 4.79 4.78 10 1 3 0 4 50 4.50 12 0 4 1 3.95 3.95 28 1 1 2 3.77 3.76 37 1 2 2 3.53 2 1 1 3.24 3.24 14 0 1 3 3.07 3.07 16 2 3 1 2.87 2.87 11 2 2 -2 2.720 2.720 15 2 2 2 2.665 2.665 11 1 3 2.546 2.546 11 2 5 0 2.492 2.491 19 0 7 2 2.202 2 4 -3 2.084 195 Table 5-11. Calculated and Observed X-ray Powder Diffraction Pattern of (Et4N)[HgAsSe3](IV). h k 1 max) mm) I/Imjobs, %) 0 2 0 9.45 9.44 72 0 1 1 9.34 9.33 100 0 2 1 7.10 7.09 19 1 1 0 6.62 6.62 9 0 3 1 5.43 5.43 10 1 2 -1 5.31 5.30 9 0 1 2 5.16 0 4 1 4.32 4.32 25 0 3 2 4.09 4.09 9 1 1 2 3.89 3.89 18 0 1 3 3.52 3.51 10 2 1 1 3.16 3.16 9 2 2 -2 3.04 3.04 10 2 3 1 2.857 1 4 -3 2.778 1 3 3 2.709 2.708 7 196 Table 5-12. Calculated and Observed X-ray Powder Diffraction Pattern of (Ph4P)2[Hg2AS4Sen](V). h k z dmA) am (A) l/Inmobs, %) 0 0 1 16.71 16.7 16 0 1 -1 12.47 12.46 50 0 1 1 11.06 11.05 100 1 0 -1 9.62 9.62 8 1 -1 0 9.42 9.41 10 0 0 2 8.35 8.35 20 0 2 0 8.20 8.20 18 1 0 1 7.44 7.43 8 0 2 2 5.53 5.53 13 0 4 0 4.10 3 -1 -3 3.26 2 -6 0 197 3. Results and Discussion 3.1 Syntheses and description of structures (Ph4P)2[Hg2AS4S9](I) was prepared by heating Hng with K3ASS3 and Ph4PBr in H20 at 130 °C. The pale-yellow crystals that formed in 2-3 days do not dissolve in common polar organic solvents, such as DMF or CH3CN, indicative of a polymeric compounds. The structure was determined by X-ray single-crystal analysis. The compound contains a one-dimensional chain structure consisting of trigonal planar Hg2+ ions and linear [AS489]6‘ units formed by corner sharing of the [AsS3]3' units. The [ngAS4S9]n2n' chains are parallel to the crystallographic a-axis and separated by Ph4P+ cations, see Figure 5-1. The chains can also be viewed as assembled by ngAs284 eight-membered puckered rings arranged side-by-side. Inside each ring resides a center of symmetry; see Figure 5-2. We have seen the [AS489]6' units before in (Ph4P)2[SnAS489] (in Chapter 2), however the bonding mode here is different. Instead of two Sn“+ centers, it now is bonded to four Hg2+ centers. The different bonding mode, once again, demonstrates the structural diversity of the thioarsenate ligands. The Hg“ is in a trigonal-planar environment with bond angles of SZ-Hg-S3 at 119.01(3)°, S2-Hg-S at 121.69(3)°, S3-Hg-S4 at ll9.28(2)°. The average Hg-S bonding distance, at 2.470(4)A, is comparable to the mean bond length, at 2.49A of other trigonal planar mercury compounds like BaHgSz12 and NazHg3S4.13 The average As-S distance of 2.277(8)A, and the average 198 Table 5-13. Selected Distances (A) in (Ph4P)2[Hg2AS489] with Standard Deviations in Parentheses.a Hg - s2 2.475(6) Hg - s3 2.465(7) Hg - S4 2.470(8) Asl - s1 2.287(8) Asl - 82 2.236(8) Asl - s3 2.272(6) As2 - s1 2.325(9) Asl - S4 222(2) As2 - S5 232(1) Table 5-14. Selected Angles (Deg) in (Ph4P)2[Hg2AS489] with Standard Deviations in Parentheses.a $2 - Hg - s3 119.01(3) 82 - Hg - S4 111.22(3) s3 - Hg - S4 ’ 128.04(3) s1 - Asl - s2 98.0(3) Sl - Asl - s3 100.9(2) s2 - Asl - s3 101.9(2) s1 - As2 - S4 94.9(6) Sl - As2 - SS 100.3(4) S4 - As2 - SS 123.1(8) aThe estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {211011 - l)2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 199 Figure S-l. Packing diagram of (P114?) 201ng8489]. 200 82 SI 54 O O O 0 H8 A31 A82 as ‘ s3 85 O 0 g 83 “8 1m Hg 0 “ O ”2 0 o 5" s1 s2 Figure 5-2. Structure and labeling scheme of one [ngAs4sg],,2n- chain. 201 S-As-S angles at 100.1(3)°, are well within the normal range found in other arsenic/sulfide compounds.l4 Selected bond distances and bond angles are contained in Tables 5-13 and 5-14. (Me4N)[HgAS3S5](II) was prepared under conditions similar to those used for (I), but with a longer reaction time (one week). The compound has a unique two-dimensional layered structure where layers of the [HgAS386]n"' covalent framework sandwich Me4N+ cations; see Figure 5-3. The interlayer distance is 9.303A. The _ [HgAS3S5]nn' framework is composed of tetrahedral Hg2+ atoms and polymeric [AS336ln3n‘ units formed by corner sharing AsS33' units, See Figure 5-4. The Hg2+ ions is in a severely distorted tetrahedral environment as indicated by the bond angles around Hg atoms that range from 94.1(2)° to 138.2(3)°. The Hg-S bond distances are divided into a set of two long bonds at 2.620(8)A and 2.768(8)A and a set of two short bonds at 2.445(9)A and 2.431(8)A. This distortion is the result of the ligand effect. Selected bond distances and bond angles arecontained in Tables 5-15 and 5-16. The Hg-Hg distance is 3.674(3)A. Both (Ph4P)2[Hg2A84S9] and (Me4N)[HgAS3S(5] feature new striking thioarsenate polyanions. Both the finite [AS489]6' and infinite [AS385],.3"', which are shown schematically below, are new species whose formation results from condensation of simpler building block [AsS3]3'. The [As386]n3"' represents a "ring-opening" polymerization product of the cyclic [AS385]3' unit observed in [Bi(AS385)2]3' (see chapter 2). 202 S S s A S I, I, \Es 578/ S S/A\5 S s/AX S A‘s A's A's A| As As A's Als As ./ s/ s (.2 v 145/w v we s—s{ s—s{ 1 1 [4545916- [ASSSGInsm Several types of rings created as the result of the unusual bonding mode of the infinite [AS386],,3"' range from the large HgAS585 twelve membered ring to the medium I-IgAS3S4 and ngAszS4 eight membered rings to the smallest Hg2S2 four membered rings. These ring are all puckered in such way to ensure that the S atoms all point into the gallery region. (Me4N)[HgAsSe3](III) and (Et4N)[HgAsSe3](IV) are synthesized with similar reactant ratios and reaction conditions. The rationale for using the small organic cations was the hope that similar higher dimensionality compounds comparable to those in the Hg/AsxSy system could be obtained . Compounds (III) and (IV) have the same one-dimensional anionic chains composed of trigonal planar Hg2+ ions and [AsSe3]3' units; see Figure 5-5. In order to maintain the same anionic framework and accomodate the large Et4N+ cations the b and c axes of (IV) increase by about 1.5A while the 0 axis remains almost unchanged. The [3 angle of compound (IV), at 99.56(2)°, also differs from that of the (III), at 91.34(2)°. 203 Table 515. Selected Distances (A) in (Me4N)[I-IgAS385](II) with Standard Deviations in Parentheses.a Hg - Sl 2.620(8) Hg - s1 2.768(8) Hg - s3 2.445(9) Hg - SS 2.431(8) Asl - s2 2.263(9) Asl - s3 2.206(9) Asl - S4 2.260(9) As2 - Sl 2.263(9) As2 - 85 2 199(9) As2 - S6 2.324(9) As3 - 82 2.279(9) As3 - S4 2.285(9) As3 - S6 2.244(9) 1‘The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {Enan - 1)2/n(n—1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 204 Table 5-16. Selected Angles (Deg) in (Me4N)[HgAS3S(5](II) with Standard Deviations in Parentheses.a Sl - Hg - Sl 94.1(2) Sl - Hg - S3 114.8(3) Sl - Hg - SS 98.9(2) SI - Hg - S3 94.0(3) Sl - Hg - SS 108.2(3) S3 - Hg - SS 138.2(3) S2 - Asl - S4 101.0(4) S2 - Asl - S3 91.6(3) S3 - Asl - S4 103.1(4) Sl - As2 - SS 96.4(3) Sl - As2-S6 101.2(3) SS - As2 - S6 95.7(3) 82 - As3 - S4 97.6(3) S2 - As3 - S6 93.1(3) S4 - As3 - S6 102.0(3) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = [2n(In - l )2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 205 Figure 5-3. Packing diagram of (Me4N)[HgA53861 206 Figure 5-4. Structure and labeling scheme of one [HgAS3561nn ' layer. 207 The [HgAsSe3lnn' has a one-dimensional chainlike structure that is very similar to that of the [ngAS4S9]n2"' (see Figure 5-1). We see the similar ngAszQ4 eight-membered puckered rings in both structures. The main difference in these two structures, shown in the following scheme, is that in [ngAS489]n2"' , with large [As489]5' ligands, the eight-membered rings do not connect to each other; in [HgAsSe3]n"', with smaller [AsSe3]3' ligands, the eight-membered ring share two common edges, see Figure 5-6. \ /s S S ills X's/8‘1“] \‘,'( ills \IIH/ RH S 5 SI 8 Se Se S’e A's / A‘s A's Ai H, Al / \S/ \S/ \S/ \ / \sSe/ g\Se/ S\ [ngAs4s9]."" [HgAsSe3]nn° The Hg“ is in a trigonal-planar environment with bond angles of Sel-Hg-Se2 at 115.25(6)°, Sel-Hg-Se3 at 119.34(5)°, Se2-Hg-Se3 at 124.70(5)°. The average As-S distance of 2.391(3)A, and the average S-As-S angles at 96.79(6)° are well within the normal range found in other arsenic/selenide compounds15. Selected bond distances and bond angles are given in Table 5-17. 208 Table 517. Selected Distances (A) and Angles (ch) in (Me4N)[HgAsSe3] (III) and (Et4N)[HgAsSe3] (IV) with Standard Deviations in Parentheses.“ (Me4N)[HgAsSe3] (III) (Et4N)[HgAsSe3] (IV) Hg - Sel 2.582(2) Hg - Scl 2.580(1) Hg - Se2 2.572(2) Hg - Se2 2.594(1) Asl - Se3 2.563(3) Hg - Se3 2.575(1) As - Sel 2.373(3) As - Scl 2.366(2) As - Se2 2.398(3) As - Se2 2.400(2) As - Se3 2.411(3) As- Se3 2.396(2) Sel-Hg-Se2 115.32(8) Sel-Hg-Se2 115.18(4) Sel-Hg-Se3 119.21(6) Sel-Hg-Se3 ll9.47(4) Se2-Hg-Se3 124.93(7) Se2-Hg-Se3 124.47(4) Sel-As-Se2 96.7(1) Sel-As-Se2 96.72(5) Sel-As-Se3 105.7(1) Sel-As—Se3 91.43(5) Se2-As-Se3 99.38(9) Se2-As-Se3 90.81(5) Hg-Sel-As 95.49(9) Hg—Sel-As 104.81(6) Hg-SeZ-As 89.94(9) Hg-SeZ-As 98.15(6) flg-SeB-As 91.39(9) Hg-Se3-As 98.82(6) aThe estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation (II = {Zn(ln - 1)2/n(n-l)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 209 Figure 5-5. Packing diagram of (Me4N)[HgAsSe3]. 210 Figure 5-6. Structure and labeling scheme of one [HgAsSe3lnfl ' chain. 211 The compound (Ph4P)2[Hg2AS4Se11](V) was prepared by heating HgClz with K3AsSe3 and Ph4PBr in H20 at 130 °C. The structure was determined by X-ray single-crystal analysis. This compound also contains one-dimensional chains consisting of both trigonal-planar and tetrahedral Hg2+ ions and [AuSe1116' units. The [Hg2A54Se11]n2"' chains are parallel to the crystallographic a axis and separated by Ph4P+ cations; see Figure 5-7. These chains can also be viewed as assembled by connecting the clusters ngAs4Se10 through monoselenide; see Figure 5-8. There are two kinds of Hg2+ ions in the chains. Hg(l) is coordinated in a distorted tetrahedral arrangement to four selenides with the Se-Hg-Se angles range from 96.5(1)° ~to 128.2(1)°. Hg(2) is in a distorted trigonal-planar environment with bond angle of Se4-Hg-Se5 at 109.1(1)°, Se4-Hg- Se6 at 124.9(l)°, SeS-Hg-Se6 at 129.9(1)°. The average As-Se distance and the average Se-As-Se angle are within the normal range found in the other arsenic/selenide compounds15 The unique feature of this compound is the [AS4Se11]6' ligand each bonded to four Hg2+ ions. The [AS43811]6' ligand represents a new selenoarsenate polyanion. These [AS48611]6' units can be viewed as the oxidative addition product of the [AS4369]6‘ and two Se2'. We have seen the sulfide analogue, [AS489]6', previously in the Hg/AsxSy system and see no reason why the selenoarsenic ligand, [AS4Se9]6', should not exist. The isolation of the (Me4N)[HgAsSe3], (Et4N)[HgAsSe3], and (Ph4P)2[Hg2AS4Se11] indicates that AsxSey polyanions are similar, yet quite different from the AsnSy anions and one should not think of them just as the seleno- analog of the sulfide system. Selected bond distances and bond angles are contained in Tables 5-18 and 5-19. 212 Table 5-18. Selected Distances (A) in (Ph4P)2[Hg2AS4Se11] with Standard Deviations in Parentheses.“ Hgl - Sel 2.648(4) Hgl — Se2 2.589(3) Hgl - Se3 2.570(3) Hgl - Se6 2.820(3) Hg2 - Se4 2.602(3) Hg2 - Se5 2.587(4) Hg2 - Se6 2.540(4) Sel - Se9 2.378(5) Se2 - A83 2.316(5) Se3 - A81 2.317(5) Se4 - A82 2.362(4) SeS - A84 2.329(5) Se6 - Se10 2.357(4) Se7 - Asl 2.381(5) Se7 - As2 2.420(5) Se8 - A82 2.389(5) Se8 - A84 2.423(4) Se9 - A83 2.389(5) Se10 - Asl 2.425(4) Sell - A83 2.417(5) Sell - A84 2.403(5) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {2n(In - l)2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 213 Table 5-19. Selected Angles (Deg) in (Ph4P)2[Hg2AS4Se11] with Standard Deviations in Parentheses.“ Sel-HgI-Se2 106.8(1) Sel-Hgl-Se3 114.6(1) Sel-Hgl-Se6 96.5(1) Se2-Hg1-Se3 128.2(1) Se2-Hg1-Se6 102.06(9) Se3-Hgl-Se6 102.7(1) Se4-Hg2-Se5 100.9(1) Se4-Hg2-Se6 124.9(1) Se5-Hg2-Se6 129.9(1) Hgl-Sel-Se9 97.0(1) Hgl-Se2-As3 99.4(1) Hgl-Se3-Asl 100.7(1) Hg2—Se4-A82 102.0(1) Hg2-Se5-As4 93.6(1) Hgl-Se6-Hg2 98.8(1) Hgl-Se6-Se10 100.5(1) Hg2-Se6-Se10 104.4(1) Asl-Se7-A82 93.4(2) A82-Se8-As4 102.7(1) Sel-Se9-A83 105.4(1) Se6-SelO-Asl 107.4(2) AS3-SCI 1-As4 98.3(2) Se3-Asl-Se7 98.7(2) Se3-Asl-Se10 107.3(2) Se7-Asl-Se10 100.3(2) Se4-As2-Se7 100.3(1) Se4-A82-Se8 94.1(2) Se7-A82-Se8 99.4(1) Se2-AS3-Se9 105.3(2) Se2-A83-Sell 97.8(2) Se9-A83-Sell 100.2(2) Se5-As4-Se8 98.0(2) Se5-As4-Se11 98.9(2) Se8-As4-Se11 102.4(2) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {2n(In - 1)2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 214 Figure 5-7. Packing diagram of (Ph4P)2[Hg2AS4Se11]. 215 Figure 5-8. Structure and labeling scheme of one [ngAS4Se11]n2n' chain. 21 6 3.2 Physicochemical studies In the far-IR region all complexes reported here exhibit spectral absorptions due to As-S and M-S stretching vibrations as shown in Figures 5-9 and 5-10. Observed absorption frequencies of all the complexes are given in Table 5-20. Table 5-20. Frequencies (cm‘l) of Raman and Infrared Spectral Absorptions of (Ph4P)2[Hg2AS489] (I), (Me4N)[HgAS385] (II), (Me4N)[HgAsse3l (III). (Et4N)[H8AsSe3] (IV). and (Ph4P)2[H82AS48611] (V)- Compounds Infrared Raman (Ph4P)2[Hg2A8489] 383(ln, sh), 362(m) 328(8). 301(m) 284(w), 263(8) 252(8) (Me4N)[HgAS385] 362(8, sh), 269(8) 226(w), 188(m) 178(m), (Me4N)[HgAsSe3] 268(m), 249(m, sh) 268(w), 252(m), 246(m) 178(m, sh) 178(8) (Et4N)[HgASSC3] 268(m), 249(m, sh) 268(w), 252(m), 246(m) 178(m, sh) 178(8) (Ph4P)2[Hg2AS4Se11] 273(8), 249(8, sh) 273(w), 249(8), 231(m) 220(8), 181(m) 217(8), 203(m), 160(m) 162(m, sh) * 8: strong, m; medium, w: weak, sh: shoulder. 217 (A) (B) TRANSMI'ITANCE to 1113 362 3110 all. 260 2138 212 178 lit unveuuneen Figure 5-9. Far-1R spectra of (A) (Ph4P)2[Hg2A8459](1), (B) (Me4N)UigAS356](II). 218 J W) ‘A’ )W N ‘3’ r 1 i l TRANSMITTANCE H s 880 Go 3% STE 360 260 550 160 via mvcmen Figure 5-10. Far-IR spectra of (A) (Me4N)[HgASSe3](III), (B) (Et4N)[HgAsSe3](IV), and (C) (Ph4P)2[ngAsttSeul(V). 219 In the Far-IR of (Ph4P)2[Hg2AS489], and (Me4N)[HgAS3S6]. the peaks in the region of 200-400 cm'1 could be attributed to As-S vibration modes. Similar assignments have been made in the far-IR spectra of other known thioarsenic complexes.16 It should be noted that it is difficult to interpret the far-IR spectra of compounds (I) and (11) without ambiguity. The major difficulty in assigning the observed IR spectra of these compounds arises from the fact that As- S and Hg-S stretching frequencies fall in the same low frequency region of 200-400 cm'l, The additional peak in the IR spectra for (Me4N)[HgA83S5] at 188 cm‘1 might be assigned as a Hg-S stretching vibration. The Far-IR spectra of (Me4N)[HgAsSe3] and (Et4N)[HgAsSe3] are identical. The peaks at 268 and 249 cm‘1 can be assigned to the As-Se vibration mode. The remaining lower energy peak at 173 cm’1 might be a Hg-Se stretching vibration. A similar assignment can also be derived for the (Ph4P)2[Hg2AS4Se11] compound. The peaks between 200-300 cm'1 can be assigned to As- Se and Se-Se vibration modes and those at 181 and 162 cm"1 can be assigned to Hg-Se stretching vibrations. Raman spectra of (III), (IV), and (V) were also recorded, but those of (I) and (II) were not because a large diffuse reflectance which obscures the area from 2000 cm'1 to 200 cm'l. We see that the Raman data of (III) and (IV) have a one to one correspondence with peaks in the infrared data with the exception of the 249 cm'1 peak in the infrared spectra which is resolved into two peaks in the Raman spectra. Assignments made to the infrared spectra can also be applied in the Raman spectra. 220 Thermal Gravimetric Analysis (TGA) results for all compounds are summarized in Table 5-21 and the graphs are shown in Figures 5-11, 5-12, and 5-13. Above 650 °C. all compounds of (I)-(V) completely lost mass without leaving any ternary Hg/AS/S(Se) or binary Hg/S(Se) phases. During pyrolysis, redox reactions must have occurred between Hg2+ metal ions and [AstyID' (Q = S, Se) to form volatile Hg and Asty (Q = S, Sc) phases. For compounds (11), (III), and (IV) there are two step weight losses. The first step can be attributed to the loss of the organic cations, probably as R3N and R28 . or R2Se, while the final step is due to the loss of Hg and ASxS(SC)y. Table 5-21. TGA Data for (Ph4P)2[Hg2AS489] (I), (Me4N)[HgAS3S(5] (II), (MC4N)[H8ASSC3] (III). (Et4N)[H8ASSe3l (IV). and (Ph4P)2[H82AS4Scn] (V)- Compound Temp. range (°C) Weight loss (%) (Ph4P)2[Hg2AS489] 230 - 485 98.1 (Me4N)[HgAS3S6] 230 - 300 30.0 300 - 525 68.5 (Me4N)[HgAsSe3] 148 - 260 22.2 260 - 610 76.0 (Et4N)[HgASSe3] 150 - 250 31.1 250 - 550 67.1 (Ph4P)2[Hg2A84Se1 1] 310 - 630 98 .2 221 120 L ‘ ' 100- (A) , r 80- “ E 3 60- *’ 40- - 20- .. 0 t 1 r 0 200 400 600 800 Temp ('C) 120 L J 1 100- (3) - 80-4 ’ S? g 60“ *- 40- - 20- " 0 l j I O 200 400 600 800 Temp ('C) Figure 5-11. TGA diagrams of (A) (Ph4P)2[Hg2AS489](I), (B) (M64N)[H8A83561(II). 120 ' ‘ ‘ 1001 80-J 60‘ W(%) 40-1 20‘ I 1 0 200 400 600 800 Temp ('C) (B) I O 200 400 600 800 Temp (°C) Figure 5-12. TGA diagrams of (A) (Me4N)[HgAsSe3](III), (B) (Et4N)[HgA5563NIV). 223 120 1 .1 ‘ 1001 _ W(%) m C l l I 7 O 200 400 600 Temp (°C) Figure 5-13. TGA diagram of (Ph4P)2[I-Ig2A848e11](V). 800 . --_..'___'-_lt an: Ai-n‘lu‘. 1 ' 224 The optical properties of compounds (I) - (V) were assessed by studying the UV/near-IR reflectance spectra of the materials. The spectra confirmed they are wide bandgap semiconductors by revealing the presence of sharp optical gaps as shown in Figures 5- 14, 5-15, and 5-16. The optical absorption spectra of (Ph4P)2[Hg2AS4Sg] and (Me4N)[HgAS3S(3] exhibit an intense, steep absorption edge from which the bandgap, E3, can be assessed at 2.9 and 2.8 eV respectively. The spectra of (III) - (V) also shows similar absorption edges with corresponding bandgaps of 2.4 eV for (R4N)[HgAsSe3] (R = Me, Et) and 2.5 eV for (Ph4P)2[Hg2AS4Se11]. The absorption is probably due to a charge-transfer transition from a primarily sulfur-based valence band to a mainly mercury-based conduction band. Based on the findings reported here, it appears that the relative solubilities of the various products determine the actual [AstyP' (Q = S, Se) species formed by condensation reactions of [AsS3]3‘. This behavior is reminiscent of the polychalcogenide complexes mentioned earlier, where metal preference, product solubility and solvent are the key factors that control product crystallization.” The condensation equilibria are most likely catalyzed by protonation reaction of the terminal sulfide groups. If true, different products are expected from similar reactions performed under aprotic solvents. It is interesting to point out the correlation that exists between the counterion size and the metal coordination number in the Hg/AsxSy system. The large Ph4P+ cations afford a one-dimensional chain structure with the 4 l 1 1 l l l ’3 3.54 (A) - :1 .o 3- - 3. a 2.5“ '- 8 2.. c U (909)294ng s48; I: g 1.5~ Eg-2.9eV r- E 1- _ O § 05 O I I I I I j 0 1 Z 3 4 S 6 7 eV 5 I J 1 I 1 J '5 B S W) . 4- - .D 3.“. '45 34 1- § (Mefitlimsg to: 2‘ Eg-2.8eV ,. 'fl 9 I! S O I T I I T I 0 1 2 3 4 5 6 7 eV Figure S-14. Optical absorption spectra of (A) (Ph4P)2[Hg2AS489](I), (B) (Me4N)[H8AS386](lI). 35 ' ' ' ' l l 23 ' (A) .. g 3‘ [\J\ ‘53 25- ' '8' 2- ‘ 5 (Me‘NflHM‘SeJ _ g 15" Eg-2.4eV '13 .— E“ 1-1 8 8 0.5- ' V) E 0 I I I I 1 I 0 1 2 3 4 5 6 7 eV A 5 j 1 I l 1 1 E W) .6 4' 7 3. if? 3... . o (rummage!) g 2.) Eg-2.4eV .. E V) a O | I 8V Figure 5-15. Optical absorption spectra of (A) (Me4N)[HgASSe3](III), (B) (Et4N)[HgAsSe3](IV). 227 1 .4 ‘- (Ph4P)2[l-lng s48°11] Eg-2.0 eV a/S absorption Coeff. (arb. units) Figure 5-16. Optical absorption spectrum of(Ph4P)2[ngAS4Se11](V). 228 Hg atoms adopting the trigonal-planar geometry, while the small Me4N+ cations produce a layered structure where the Hg atoms can assume tetrahedral coordination. This behavior is reminiscent of similar counterion size effects observed in silver polyselenides18 where the coordination number of Ag in [AgnSeyPl' anions varied inversely with the size of counterion. Furthermore, the dimensionality of the structures in (Ph4P)2[Hg2AS489] and (Me4N)[HgA8385], as well as in (Ph4P)2[InAS3S7] and (Me4N)2Rb[BiA85S12], is consistent with the view expressed earlier, that small cations tend to stabilize higher dimensionality anionic M/Q frameworks than corresponding large cations.19 This, however, is not yet an established trend, and one can certainly find cases (especially in zeolites) where a given cation may give rise to different structure types or different cations give rise to the same framework. The cation size/structure correlation seems to be stronger when the stoichiometry of the anionic M/Q framework is the same from cation to cation.20 We did not see this type of cation dependence in the Hg/AsxSey system. The reason may be because of simple crystal packing forces: the As-Se distance is longer than the As-S distance. These distance differences may result "[Hg2A84Se9JZ'” chains generate more empty space than As—S chain to be able to pack with Phth+ cations, and in order to get good packing the system rearranges to form [AS4Se11]4' units. We also like to point out that isolation of compounds (III) (IV) and (V) desmonstrates that the [AsxSeyln' anions are very different from the [AsnSyP' anions. This observation is consistent with our knowledge from the the metal chalcogenide chemistry that polyselenides and polytellurides are not 229 just an extension of the polysulfides. Although the condensation process probably also occurs in the [ASxSeyln' system, the solubilities of different [AsnSeyPl' polyanions may be different from those of the [AsxSyP' anions. The Hg2A82Q4 ( Q = S, Se) eight-membered ring appears to be a very stable fragment as we see it in both [ngAS4S9]2’ and [HgAsSeg]: In summary, the employment of the hydrothermal technique in the organic cation/Mn+/ASQ33' (Q = S, Se) system has successfully produced novel metal/arsenic/sulfide(Selenide) covalent frameworks. Further investigations are in process to delineate the factors responsible for influencing the dimensionality of the; final products and to achieve three-dimensional frameworks. 230 REFERENCES (a) Liao, J.-H.; Kanatzidis, M. G. Inorg. Chem. 1992, 31 , 431-439. (b) Liao, L.-H.; Kanatzidis, M. G. J. Am. Chem. Soc. 1990, 112, 7400-7402. (c) Huang, S.-P.; Kanatzidis, M. G. J. Am. Chem. Soc. 1992, 114, 5477-5478. (d) Kim, K.-W.; Kanatzidis, M. G. J. Am. Chem. Soc. 1992, 114, 4878-4883. (e) Dhingra, S. S.; Kanatzidis, M. G. Science, 1992, 258, 1769-1772. (a) Sheldrick, W. S. Z. Anorg. AIIg. Chem. 1988, 562, 23-30. (b) Sheldrick, W. S.; Hanser, H.-J. Z. Anorg. AIIg. Chem. 1988, 55 7, 98-104. (c) Sheldrick, W. S.; Hanser, H.-J. Z. Anorg. Allg. Chem. 1988,557, 105-110. (a) Wood, P. T.; Pennington, W. T.; Kolis, J. W. Inorg. Chem. 1993, 32, 129-130. (b) Wood, P. T.; Pennington, W. T.; Kolis, J. W. J. Chem. ~Soc. Chem. Commun. 1993, 25, 235-236. (a) Parise, J. B. Sicence, 1991, 251, 293-294. (b) Parise, J. B.; Ko, Y. Chem. Mater. 1992, 4, 1446-1450. Chou, J.-H.; Kanatzidis, M. G. Inorg. Chem. 1994,33, 1001-1002. Chou, J.-H.; Kanatzidis, M. G. maniscript in preparation. Chou, J.-H.; Kanatzidis, M. G. Inorg. Chem. 1994, In press.. (a) Wendlandt, W. W.; Hecht, H. G. "Reflectance Spectroscopy”, Interscience Publishers, 1966. (b) Kotiim, G. "Reflectance 10. 11. 12. 13. 14. 15. 23 1 Spectroscopy”, springer Verlag, New York, 1969. (c) Tandon, S. P.; Gupta, J. P. Phys. Stat. Sol. 1970, 38, 363-367. Sheldrick, G. M. In Crystallographic Computing 3; Sheldrick, G. M.; Kruger, C.; Goddard, R., Eds.; Oxford University Press: Oxford, U.K., 1985; PP 175-189. TEXSAN: Single Crystal Structure Analysis Package, Version 5.0, Molecular Structure Corp., Woodland, TX. Walker, N.; Stuart, D. Acta. Crystallogr. 1983,39A, 158-166. Rad, H. D.; Hoppe, R. Z. Anorg. AIIg. Chem. 1981, 483, 18-25. Siewert, B.; Miiller, U. Z. Anorg. AIIg. Chem. 1991,595, 211- 215. (a) Sommer, H.; Hoppe, R. Z. Anorg. Allg. Chem. 1977, 430, 199. (b) Sheldrick, W. S.; Kaub, J. Z. Naturforsch. 1985, 40b, 571- 573. (c) Jerome, J. E.; Wood, P. T.; Pennington, W. T.; Kolis, J. W. Inorg. Chem. 1994,33, 1733-1734. (a) Sheldrick, W.; Hausler, H.-J. Z. Anorg. AIIg. Chem. 1988, 561, 139-148. (b) Sheldrick, W.; Kaub, J. Z. Anorg. AIIg. Chem. 1986, 535 , 179-185. (c) O'Neal, S. C.; Pennington, W. T.; Kolis, J. W. J. Am. Chem. Soc. 1991, 113, 710-712. (d) O'Neal, S. C.; Pennington, W. T.; Kolis, J. W. Inorg. Chem. 1992, 31, 888- 894. 16. 17. 18. 19. 20. 232 (a) Mohammed, A.; Miillcr, U. Z. Anorg. Allg. Chem. 1985.523, 45-53. (b) Sinning, H.; Miiller, U. Z. Anorg. Allg. Chem. 1988, 564, 37-44. Kanatzidis, M. G.; Huang, S.-P. Coord. Chem. Rev. 1994, 130, 509-621. Huang, S.-P.; Kanatzidis, M. G. Inorg. Chem. 1991,30, 1455- 1466. Kim, K.-W.; Kanatzidis, M. G. J. Am. Chem. Soc. 1992, 114, 4878- 4883. Kanatzidis, M. G. In Proceeding of the 7th International Symposium on Inorganic Ring Systems, Banff, Canada, 1994, Phosphorous, Silicon, and Sulfur, in press. 8" . ... .5 233 CHAPTER 6 HYDRO(METHANO)THERMAL SYNTHESIS OF M/Asty (M = Ag2+, Q = 8, Se) COMPOUNDS. SYNTHESIS AND CHARACTERIZATION OF B-Ag3AsSe3(I), (Me3NH)[Ag3A82Se5](II), K5[Ag2AS3Se9](III), and K[Ag3A8285](IV). 234 ABSTRACT B-Ag3AsSe3(I) and (Me3NH)[Ag3A82$e5](II) were synthesized hydrothermally from a mixture of AgBF4/3K3AsSe3 and AgBF4/3K3A8Se3/Me3NHCl, while K[Ag3A82S5](III) and K5[Ag2AS3Se9](IV) were synthesized methanothermally from a mixture of AgBF4/3K3AsSe3 and AgBF4/3K3ASS3, respectively. The structures were determined by single-crystal X-ray diffraction analysis. B-Ag3AsSe3(I) crystallizes in orthorhombic space group ana (No. 62) with a = 8.111(1)A, b = 11.344(2)A, c = 20.728(3)A, z = 8, V = 1907(1)A3. The compound is a new allotrope of the known Ag3AsSe3 and has a complicated three-dimensional Structure composed of three and four coordinated Ag+ ions and [ASSe3]3' units. (Me3NH)[Ag3A828e5] crystallizes in the triclinic space group P-l (No. 2) with a = 10.549(2)A, b = 11.476(4)A, c = 6.549(3)A, a = 104.94, p: 107.41(2)°, 7 = 88.78, 2 = 4, V = 2640(2)A3. The [Ag3A82Se5]n"' macroanion has a very complicated two-dimensional layered structure composed of tetrahedral Ag+ ions and [AS2Se5]4' units. The compound K5[Ag2AS3Se9] crystallizes in the orthorhombic space group ana with a = 12.599(2)A, b = 12.607(4)A, c = 14.067(3)A, z = 8, V = 2234(1)A3. The [AngS3Se9]n5"' macroanion has a two- dimensional layered structure with tetrahedral Ag+ ions and two different selenoarsenate units, [AsSe4]3' and [AszSe5]4'. The K[Ag3A8285] also crystallized in orthorhombic Space group ana with a = 19.210(2)A, b = 16.867(2)A, c = 6.3491(7)A, z = 8, v = 2057.2(7)A3. The [Ag3A82S51nn' macroanion also possesses a two- dimensional layered structure with tetrahedral Ag+ ions and two 235 different thioarsenate ligands, [ASS3]3' and [AS38715'. The solid state optical and vibrational spectra of these compounds are reported. 236 1. Introduction Recently, by hydrothermal synthesis, our exploration of the system R4E+ (R = alkyl, Ph, E = N, P)/Mn+/ASS33' led to the synthesis of several novel metal thioarsenate compounds, including [InA83S7]2', [BiAsoSlzl3'.1 [H8A83861' [H82A84891232 [Pt(Asssslzlz'. [l’t3(:“-sS4l3l3'-3 In these compounds the [ASS3]3' anion shows a facile condensation ability that results in high nuclearity [AsxSyPl' units, see Eq. 1-4, which are found coordinated to the metal cations. A8833“ + Ass,“ . - [As,s,]" + 5" (Eq. 1) [413,851" 4 Ass: - 5 [As38715' + 8" (Eq. 2) [AsnS-Js' 4 Ass? . ~ [As,s,]°' + 82' (Eq. 3) [as,s,]s- - - weasel" + 5" (Eq. 4) We achieved, however, little success when MM = Ag+. In our initial work with silver, we repeatedly got the known Ag3AsS3 (proustite) compound, without incorporation of the cations. We then decided to explore the corresponding selenoarsenate anions by using [ASSe3]3' as a reactant, The chemistry of selenoarsenic polyanions is not well developed, but the [AsSe3]3' units are known to occur in solid state compounds, the so-called sulfosalts, as in Ag3AsSe3 and TlAsSe3. F' 237 W. S. Sheldrick and co-workers have shown that the hydrothermal technique provides an easy route to prepare a large number of ternary As/Se compounds by Simply reacting an alkali metal carbonate with a binary mixed 15/16 phase.“'9 For example: 130 °C/HZO M2C03 + P182863 ‘ MASSC3 M = K, Rb, CS The MASSe3 (M = K, Rb, Cs) contain selenoarsenate anions, [ASSe3]“‘, in which the arsenic atom is bonded to a monoselenide and a diselenide into infinite single chains. In the field of solution chemistry, it was found that WSe42' and MoSe42' attack AS4Se4 cages to form (Ph4P)2[W2(u-Se)3(AsSe5)2] and (Ph4,P)2[Mo(AsSe5)2].10 Both compounds contain two unusual [AsSc5]3’ groups as capping ligands. It was also found that [AS48e5]2' can oxidatively decarbonylate to Mo(CO)5 and W(CO)(, to form (Ph4P)2[M(CO)2(AS3Se3)2] (M = M0, W).11 The chemistry of these molecular complexes was all done in polar solvents at ambient temperature. From the structures of (Ph4P)2[Hg2A8489], (Me4N)2[HgAS3Se6], (Me4N)[HgAsSe3], (Et4N)[HgAsSe3], and (Ph4P)2[Hg2AS4Se11], (see chapter 5) we learned that thioarsenate ligands and selenoarsenate ligands form different [AsgSyP' and [AsnSeyP‘ species from condensation reactions and behave differently toward metal ions. With this in mind, we investigated the system Ag/AsxSey hoping that it would be different from the Ag/AsxSy system. During this investigation we found that if we used 238 methanol instead of water as a solvent we could avoid formation of the Ag3AsQ3 (Q = S, Se)(proustitc) compound. We report here the synthesis, structural characterization, and optical properties of four novel Ag/Asty (Q = S, Se) compounds, B-Ag3AsSe3(I), (Me3NH)[Ag3A828e5](II), K5[Ag2AS3Sc9](III), and K[Ag3A82S5](IV) from hydrothermal and methanothermal synthesis. 2. Experimental Section 2.1 Reagents Chemicals in this work other than solvents were used as obtained: (i) selenium powder, ~ 100 mesh, 99.5% purity, Sliver tetrafloroboride, AgBF4, 99.5% purity, trimethylammonium chloride, Me3NHCl, 99% purity, tetramethylammonium chloride, Me4NCl, 99% purity, tetraethylammonium bromide, Et4NBr, 99% purity, Aldrich Chemical Company, Inc., Milwaukee, WI; (ii) arsenic sulfide, A8283, 100 mesh, 99% purity, arsenic selenide, A828e3, ~200 mesh, 99% purity, Cerac Inc. Milwaukee WI; (iii) potassium metal, analytical reagent, Mallinckrodt Inc., Paris, KY; (iv) Methanol, anhydrous, Mallinckrodt Inc., Paris, KY; diethyl ether, ACS anhydrous, EM Science, Inc., Gibbstown, NJ. 2.2 Physical Measurements The instruments and experimental setups for Infrared measurements, optical diffuse reflectance measurements, and quantitative microprobe analysis on SEM/EDS are the same as those reported in Chapter 2. Differential Thermal Analysis (DTA) was 239 performed with a computer-controlled Shimadzu DTA-50 thermal analyzer. The single crystals (~ 10.0 mg total mass) were sealed in Quartz ampules under vacuum. An empty Quartz ampule of equal mass was sealed and placed on the reference side of the detector. The samples were heated to the desired temperature at 10 °C/min, held isothermal for 10 min and then cooled at 10 °C/min to room temperature. The reported DTA temperatures are peak temperature. The DTA samples were examined by powder X-ray diffraction after the experiments. 2.3 Syntheses All syntheses were carried out under a dry nitrogen atmosphere in a vacuum atmosphere Dri-Lab glovebox except were specifically mentioned. K3ASS3(K3AsSe3) was synthesized by using stoichiometric amounts of alkali metal, arsenic sulfide(selenide), and sulfur(selenium) in liquid ammonia. The reaction gives a yellow (orange) brown powder upon evaporation of ammonia. B-Ag3AsSe3(I): A Pyrex tube (.. 4 mL) containing AgBF4 (0.02 g, 0.1 mmol), K3ASSe3 (0.144 g, 0.3 mmol), Et4NBr (0.10 g, 0.6 mmol) and 0.3 mL of water was sealed under vacuum and kept at 110 °C for one day. Large black needle-like crystals with metallic shine were isolated by washing the excess starting material and KCl with H20, MeOH and anhydrous ether. (Yield = 84.5%, Based on Ag). The infrared spectroscopy indicated the absence of organic cations. Semiquantitative microprobe analysis on single crystals gave 240 Ag3A818e3; however, the XRD did not match with any known Ag/AS/Se ternary phases. The procedures were later modified to prepare this product in the absence of organic cations. The Optimized reaction ratio of lAgBF4/3K3A8Se3 gave a yield close to 99% based on Ag. Given that another compound with the formula Ag3AsSe3 is known, we will refer to (I) as B-AggAsSe3 and to the known phase as a-Ag3AsSe3. (Me3NH)[Ag3A82Se5](II): A Pyrex tube (~4 mL) containing AgBF4 (0.02 g, 0.1 mmol), K3AsSe3 (0.144 g, 0.3 mmol), Me4NCl (0.10 g, 0.6 mmol) and 0.3 mL of water was sealed under vacuum and kept at 110 °C for one day. The large dark-red transparent plate-like crystals that formed were isolated by washing with H20, MeOH and anhydrous ether. (Yield = 99%, Based on Hg). Although we started with Me4N+ as the cation the presence of Me3NH+ cations was confirmed with infared spectroscopy and was further proved by synthesizing the compound with Me3NH+ as the counterion. Semiquantitative microprobe analysis on single crystals gave Ag2A81Se2. K5[Ag2A83Se9](III): A Pyrex tube (.. 4 mL) containing AgBF4 (0.02 g, 0.1 mmol), K3AsSe3 (0.144 g, 0.3 mmol), Ph4PBr (0.419 g, 1 mmol) and 0.5 mL of methanol was sealed under vacuum and kept at 110 °C for one week. Large black block-like crystals were isolated by removing the excess starting material and KC] with H20, MeOH and anhydrous ether( yield = 75% based on Ag). Quantitative microprobe analysis on single crystals gave K2,1Ag1A81,6Se3,9. The procedure was later modified to avoid the use of organic counterions. 241 The optimized reaction ratio of AgBF4/K3AsSe3 is 1:3 with the yield close to 90% based on Ag. K[Ag3A8285](IV): A Pyrex tube (~4 mL) containing AgBF4 (0.02 g, 0.1 mmol), K3ASS3 (0.144 g, 0.3 mmol), Ph4PBr (0.419 g, 1 mmol) and 0.5 mL of methanol was sealed under vacuum and kept at 110 °C for one week. Large brown-yellow chunky crystals were isolated by washing the excess starting material and KCl with H20, MeOH and anhydrous ether ( yield = 65% based on Ag). Quantitative microprobe analysis on single crystals gave K1Ag2,5A81,5S4,5. The procedure was later modified to avoid the use of organic counterions. The optimized reaction ratio of AgBF4/K3ASS3 is 1:3 with the yield close to 85% based on Ag. 2.4 X-ray crystallography Single-crystal X-ray diffraction data of all four compounds were collected at 23 °C with a Rigaku AFC6 diffractometer equipped with a graphite-crystal monochromator. The data were collected with a 9/29 scan technique. None of the four crystals showed a significant intensity decay as judged by three check reflections measured every 150 reflections through the data collection. Space groups were determined from Systematic absences and intensity statistics. The structures were solved by the direct methods of SHELXS-8612 and refined by the full-matrix least-squares techniques of the TEXSAN13 software package of crystallographic programs. An empirical absorption correction based on lit-scans was applied to each 242 data set, followed by a DIFABS14 correction to the isotropically refined structures. All nonhydrogen atoms except carbon and nitrogen were eventually refined anisotropically. All calculations were performed on a VAXstation 3100/76 computer. The complete data collection parameters and details of the structure solutions and refinements are given in Tables 6-1 and 6-2. The fractional atomic coordinates, average temperature factors, and their estimated standard deviations are given in Tables 6-3, 6-4, 6-5, and 6-6. 243 Table 6-1. Crystallographic Data (MegNH)[AggAszSes](II). . for B-Ag3AsSe3(I) I II Formula Ag3ASSe3 C3H10NAg3AszSe5 F. w. 635.41 928.25 a,A 8.111(1) 10.549(1) b, A 11.344(2) 11.477(2) c, A 20.728(3) 6.5491(8) 01, deg. 90.00 104.94(1) [3, deg, 90.00 107.40(8) 7, deg. 90.00 88.78(1) 2, v, A3 12, 1907(1) 2, 729.6(4) Space Group ana(No. 62) P-1(No.2) color, habit Black, needle Dark red, plate Dcnlc, g/cm3 6.64 4.22 Radiation Mo Kat Mo K0 )1, cm'1 311.11 207.65 20m", deg. 45.0 45.0 Absorption Correction \y scan \v scan Transmission Factors 0.86-1.04 0.80-1.32 Index ranges 05 h 512, 05 k 522, 05 h 513, -145 k 514, ~ 05159 -85 i 58 No. of Data coll. 1791 2027 Unique reflections 16 7 6 1 9 01 Data Used 760 997 (Fo2 > 30(Fo2)) No. of Variables 106 107 Final R“/wa, % 6.7/7.9 4.4/4.7 a R: Z(lFo|-ch|)/Z|Fol, b Rw={Zw(|Fo|-|Fc|)2/Zw|Fo|2}1,2. 244 Table 6-2. Crystallographic Data for K5[Ag2A83Se9](III) K[Ag3A82S5](IV). I I I I V Formula K5Ag2AS3Se9 KAg3A8285 F. w. 1346.65 672.55 a, A 12.599(2) 19.210(2) b, A 12.607(3) 16.867(2) c, A 14.067(3) 6.3491(7) 01, deg. 90.00 90.00 [3, deg. 90.00 90.00 7, deg. 90.00 90.00 2, v, A3 8, 2234(1) 8, 2057.2(7) Space Group ana(No. 62) ana(No. 62) color, habit Black, block Yellow brown, needle Dcalct g/cm3 4.00 4.34 Radiation Mo K01 Mo K0: )1, cm'1 215.77 133.00 20m“, deg. 45.0 45.0 Absorption Correction w scan w scan Transmission Factors 0.51-1.00 0.89-1 .18 Index ranges 05h514, O5k514, 05h518, 05k521, 051515 05157 No. of Data coll. 1856 1723 Unique reflections 1703 1627 Data Used 843 768 (Fo2 > 30(Fo2)) No. of Variables 9 7 106 Final R“/wa, % 4.0/4.5 4.0/4.7 a R: 2(lFol-chl)/E|Fol, b Rw={2w(lFol-|Fcl)2/£wlFo|2}1/2. Table 6-3. Selected Atomic Coordinates and Estimated Standard 245 Deviations (esd's) of B-AggAsSe3(I). atom X Y Z Beg 8. (A2) Agl 0.6435(6) -0.0180(4) 0.6779(2) 1.5(2) A32 0.3314(5) 0.1101(4) 0.7155(2) 1.6(2) Ag3 0.8779(6) -0.0348(4) 0.5601(2) 1.4(2) Ag4 0.7139(6) 0.0714(4) 0.4424(2) 1.9(2) AgS 0.7766(9) -0.2500 0.6312(4) 1.3(3) Sel 0.613(1) 0.2500 0.7120(4) 0.7(4) 362 0.988(1) -0.2500 0.5318(4) 1.1(4) Se3 0.1200(7) 0.0889(6) 0.6187(3) l.0(3) Se4 0.4164(7) -0.0962(5) 0.7686(3) 0.8(3) Se5 0.454(1) -0.2500 0.6095(4) 0.9(4) Se6 0.6009(7) 0.0837(5) 0.5629(3) 1.1(3) Asl 0.748(1) 0.2500 0.6078(4) 0.6(4) A82 0.220(1) 0.2500 0.5539(5) 0.7(4) A83 0.287(1) -0.2500 0.7082(6) 1.3(4) “ Bnq=(4/3)[a2B11 + b2B22 +c2B33 + ab(cosy)B12 + ac(cosB)B13 + bc(cosa)B23]. 4‘» Ava '_ Table 6-4. Selected Atomic Coordinates and Estimated Standard 246 Deviations (esd's) of (Me3NH)[AS3A82Se5](II). atom x Y z Beg, (A2) Ag(l) 0.8318(3) 0.1222(2) 0.2789(4) 3.1(1) Ag(2) 0.6153(2) -0.0699(2) -0.025(4) 2.8(1) Ag(3) 0.9225(3) 0.1580(2) 0.8225(4) 3.8(1) Se(l) 0.7384(3) 0.2691(2) 0.5915(4) 1.7(1) Se(2) 1.0396(3) 0.2355(3) 0.2506(4) 1.8(1) Se(3) 0.5991(3) 0.1693(3) -0.0333(4) 1.8(1) Se(4) 0.6182(3) -0.2114(2) -0.4170(4) 1.5(1) Se(S) 0.8387(3) -0.1161(3) 0.2712(4) 1.8(1) As(l) 0.5867(3) 0.1183(3) 0.5867(4) 1.5(1) As(2) 1.1818(3) 0.0856(2) 0.3646(4) 1.5(1) N 1.235(2) 0.424(2) 0.805(4) 2.8(5) C(1) 1.271(3) 0.501(3) 0.687(5) 4.0(7) C(2) 1.332(4) 0.422(4) 1.005(6) 6.2(9) C(3) 1.105(5) 0.452(4) 0.855(7) 6.7(9) “ B¢q=(4/3)[a2B11 + bZBzz +c2B33 + ab(cosy)B12 + ac(cosB)B13 + bc(cosot)B23]. 247 Table 6-5. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of K5[Ag2AS3Se9](III). atom X Y Z BPS “, (A2) Ag 0.2369(1) 0.0892(2) 0.7118(2) 2.16(9) Sel 0.3547(3) -0.2500 0.5712(3) 1.5(2) Se2 0.2825(2) 0.2500 0.8258(3) 1.2(1) Se3 0.0358(2) 0.0958(2) 0.6494(2) 1.4(1) Se4 0.2853(2) -0.1001(2) 0.7974(2) 1.6(1) SeS 0.0741(3) -0.2500 0.6552(3) 2.1(2) Se6 0.3781(2) 0.1025(2) 0.5681(2) 1.6(1) Asl 0.2481(2) -0.2500 0.7051(3) 1.1(1) A82 -0.036S(2) 0.2500 0.7165(2) 0.9(1) A83 0.4835(2) 0.2500 0.6010(3) 1.3(2) K1 0.1787(4) -0.0718(4) 0.4961(4) 2.3(3) K2 0.9796(4) 0.0801(4) 0.1694(4) 2.2(2) K3 0.1707(6) 0.2500 0.4897(7) 2.2(4) a B¢q=(4/3)[a2B11 + szzz +CZB33 + ab(cosy)Blz + ac(cosB)Bl3 + bc(cosot)B23]. "r-AT-‘ulf- 248 Table 6-6. Selected Atomic Coordinates and Estimated Standard Deviations (esd's) of K[Ag3A8285](IV). atom X Y Z Beg “, (A2) Agl 0.6851(1) 0.3690(1) 0.0892(4) 3.1(1) A32 0.7332(1) 0.5239(1) -0.0909(4) 4.2(1) Ag3 0.8572(1) 0.3669(1) -0.1605(3) 3.3(1) Asl 0.7870(2) 0.2500 0.4088(6) 1.0(1) A82 0.5884(1) 0.4603(1) 0.5950(4) 1.2(1) A83 0.6069(2) 0.2500 0.5118(6) 1.0(1) K 0.4786(3) 0.3776(3) 0.0894(9) 1.8(2) Sl 0.3806(4) 0.2500 -0.119(1) 1.4(4) $2 0.8151(3) 0.3558(4) 0.209(1) 1.4(3) S3 0.6071(3) 0.4913(3) 0.256(1) 1.2(2) S4 0.5232(3) 0.3456(3) 0.579(1) 1.1(2) SS 0.6914(3) 0.4075(3) -0.311(1) 1.2(3) S6 0.6068(5) 0.2500 0.161(1) 1.6(4) “ Bnq=(4/3)[a2B11 + b2B22 +czB33 + ab(cosy)B12 + ac(cosB)B13 + bc(cosot)B23]. 249 The compounds were examined by X-ray powder diffraction for the purpose of phase purity and identification. Accurate dhkl spacings (A) were obtained from the powder patterns recorded on a calibrated (with FeOCl as internal standard) Phillips XRG-3000 computer-controlled powder diffractometer with graphite- monochromated Cu Ka radiation operating at 35 kV and 35 mA. The data were collected at a rate of 0.12°/min. Based on the atomic coordinates from the X-ray single crystal diffraction study, X-ray powder patterns for all compounds were calculated by the software package CERIUS.14 Calculated and observed X-ray powder patterns that Show d-Spacings and intensities of strong hkl reflections are complied in Tables 6-7 to 6-10. 250 Table 6-7. Calculated and Observed X-ray Powder Diffraction Pattern of B-Ag3ASSe3(I). h It I mM) (529, (A) l/IMQbs, 90) 1 0 2 6.38 6.38 13 0 1 3 5.90 0 2 0 5.67 5.67 27 1 0 3 5.26 5.25 47 1 1 3 4.77 4.77 14 2 0 0 4.06 4.05 38 2 1 0 3.82 3.82 77 1 0 5 3.69 3.69 12 2 1 2 3.58 3.58 10 0 0 6 3.45 3.45 34 1 0 6 3.18 3.17 10 1 2 5 3.09 3.09 17 1 3 3 3.07 3.07 97 1 1 6 3.06 3.06 65 2 0 5 2.90 2.90 54 0 4 0 2.83 2.83 14 2 1 5 279 2.79 30 0 3 5 1 2 6 2.77 2.77 45 2 3 2 2.67 2.67 55 1 3 5 2.64 2.64 28 1 4 2 2.59 2.59 67 0 0 8 2 2 5 2.58 2.58 79 2 3 3 2.56 2 56 100 1 4 3 2.49 2.49 36 1 3 6 2.43 2.43 15 3 2 2 2.36 2.35 65 0 2 8 2 4 1 2.30 2.30 32 3 2 3 3 0 5 2.264 2.264 40 0 5 1 2.255 2.255 10 3 2 4 2.205 2.206 78 2 4 3 ONN45-h-FWOH-ht-“Nwt—v—wtow O‘UJMWWNWO‘NNWMONWOMW O‘HQWNwO‘Ou—OOCQ‘OOOO‘O‘H 2.187 2.159 2 129 2.064 p—h .996 .980 .910 y—ap—a 1.891 .855 .840 .761 730 .717 .658 Hp—al—AHH 251 2.187 2.158 2.13 2.063 p—i .994 .980 .910 .891 .855 .840 .717 .658 18 25 92 20 10 25 85 50 25 10 10 20 253 Table 6-9. Calculated and Observed X-ray Powder Diffraction Pattern of K5[Ag2AS3Se9](III). h It I am (A) am (A) ”Mobs, %) 0 1 1 9.39 9.38 31 o 0 2 7.03 7.03 67 0 2 0 6.30 6.30 14 2 0 0 1 0 2 6.14 6.14 28 2 1 1 5.23 5.23 11 2 0 2 4.69 4.68 18 1 0 3 4.39 4.39 15 0 3 1 4.02 4.01 10 1 3 1 3.83 3.83 34 3 0 2 3.60 3.59 15 1 3 2 3.47 3.46 15 2 3 1 3.39 1 14 3.27 4 0 0 3.15 3.15 11 2 3 2 3.13 3.13 70 0 3 3 2 0 4 3.07 3.07 35 1 3 3 3.03 3.03 100 4 0 2 2.87 2.87 57 1 0 5 2.74 2.73 50 3 3 2 1 3 4 2.63 2 0 5 2.57 2.57 10 1 3 5 2.30 2.30 12 4 3 3 2.22 2.22 15 0 6 0 210 2 10 55 3 3 5 2.04 2.04 15 1 3 6 2.02 5 3 3 1.963 1.963 24 6 3 0 1.878 1.878 22 253 Table 6-9. Calculated and Observed X-ray Powder Diffraction Pattern of K5[Ag2AS3Se9](III). h It 1 arm (A) am (A) m,m (obs, 96) 0 1 1 9.39 9.38 31 0 0 2 7.03 7.03 67 0 2 0 6.30 6.30 14 2 0 0 1 0 2 6.14 6.14 28 2 1 1 5.23 5.23 11 2 0 2 4.69 4.68 18 1 0 3 4.39 4.39 15 0 3 1 4.02 4.01 10 1 3 1 3.83 3.83 34 3 0 2 3.60 3.59 15 1 3 2 3.47 3.46 15 2 3 1 3.39 1 14 3.27 4 0 0 3.15 3.15 11 2 3 2 3.13 3.13 70 0 3 3 2 0 4 3.07 3.07 35 1 3 3 3.03 3.03 100 4 0 2 2.87 2.87 57 1 0 5 2.74 2.73 50 3 3 2 1 3 4 2.63 2 0 5 2.57 2.57 10 1 3 5 2.30 2.30 12 4 3 3 2.22 2.22 15 0 6 0 2 10 2 10 55 3 3 5 2.04 2.04 15 1 3 6 2.02 5 3 3 1.963 1.963 24 6 3 0 1.878 1.878 22 254 Table 6-10. Calculated and Observed X-ray Powder Diffraction Pattern of K[Ag3Asstl(IV). h It 1 ‘1er (A) am (A) 1/1,,m (obs, 96) 2 0 0 9.60 9.60 100 0 2 0 8.43 8.42 14 2 2 0 6.33 ‘ 6.32 8 1 0 1 6.02 6.01 10 2 0 1 5.29 5.29 14 2 1 1 5 05 1 3 1 411 4 11 10 4 1 1 3.73 3.73 13 5 0 1 3.28 ' 3.28 35 5 1 1 3.22 3.22 19 2 5 0 3.18 3.19 10 1 1 2 3.08 3.08 25 6 2 0 2.99 2.99 10 1 5 1 2.94 2.94 67 6 0 1 2.86 2.86 18 5 3 1 2.83 2.83 20 4 4 1 3 1 2 2.80 2.80 10 1 3 2 2.73 2.73 14 6 4 0 2.55 2.55 54 7 0 1 2.51 2.51 10 1 4 2 3 4 2 2 35 2.35 35 0 8 0 2.10 2.10 10 255 3. Results and Discussion 3.1 Syntheses and description of structures B-Ag3AsSe3(I) was originally synthesized with tetraethylammoninum cations present in the reaction mixture. Although the synthesis can be accomplished without the organic cations, only microcrystalline powder can be obtained. Single crystals were only obtained upon addition of tetraethylammoninum chloride. The role of the cations is still unclear, but it may act as a mineralizer. The structure was solved by single-crystal x-ray diffraction analysis. B-AggAsSegG) has a very complicated three- dimensional dense-packed structure; see Figures 6-1, 6-2, and 6-3. The basic building block is the [AsSe3]3' units which engage in several very complex bonding modes in linking the Ag+ ions together; see Scheme 6-1. As Ag A A8 A 8 A \ _ / 8 )3 sc/ A8>s/ \Sc/ 8 e 36 A c -‘A A e g‘A Ag78\/?Ag g/\/'-,g g/\/'-,g Aguuo' SIC "’A / SC\ / SC\ \ g A I A A8 | Ag A8 Ag Ag Ag Scheme 6-1 The Ag+ atoms are found in several different coordination environments. The geometry around Ag(l), Ag(3), and Ag(4) is distorted trigonal planar with normal Ag-Se bond distances (2.665A). The tetrahedral geometry around the Ag(2) is Slightly distorted with 256 two long Ag(2)-Se(l) bonds, at 2.785(7) and 2.812(8)A, and two normal Ag-Se bonds, at 2.651(6) and 2.676(7)A. The Se-Ag(2)-Se angles range from 92.8(3)° to 124.3(3)°. The tetrahedral environment around the Ag(5) is highly distorted with two very long Ag-Se "bonds" at 2.939(7)A, and two normal Ag-Se bonds at 2.663(7) and 2.681(9)A. The Se-Ag(5)-Se angles range from 72.8(3)° to 120.0(3)°. Detailed bond distances and angles are given in Tables 6- 11 and 6-12. The major difference between this compound and the well known sulfosalt, a-AggAsSe3, is that in the latter the Ag+ ions are coordinated to three Se atoms; see Figure 6-1(B). The geometry around the Ag atoms in the 0t-form can best be described as bent-T shaped with the Se-Ag-Se angles ranging from 159° to 85°. The bent-T centers all point toward the same direction with the result that crystallization occurs in the acentric space group, R3c (No. 161). In our compound which is centrosymmetric, B-Ag3AsSe3(I), the Ag+ ions are both three- and four- coordinated. This is consistent with the fact that the density of B-Ag3AsSe3 is 0.12 g/cm3 higher than that of a-AggAsSe3, This compound may have eluded mineralogists for such long time because it may be meta-stable given the mild conditions under which it was synthesized. Traditional sulfosalt synthetic conditions typically involve heating stiochiometric amount of elements at temperatures in excess of 1000 °C. The B-Ag3AsSe3(I), however, was synthesized from AgBF4/3K3A8Se3, hydrothermally at 110 °C in one day, suggestive that it is only a kinetically stable phase. In a way, this suggestion is quite puzzling. when we consider that B-Ag3ASSe3 is 257 Table 6-11. Selected Distances (A) in B-AggAsSe3 with Standard Deviations in Parentheses.“ Agl - Ag2 3.021(6) Agl - Ag2 3.053(5) Agl - Ag3 3.101(6) Agl - Ag5 3.005(6) Agl - Se4 2.778(5) Agl - Se4 2.630(5) Agl - Se6 2.671(7) Ag2 - Sel 2.785(7) Ag2 - Sel 2.812(8) Ag2 - Se3 2.651(6) Ag2 - Se4 2.676(7) Ag3 - Ag4 3.028(6) Ag3 - Ag5 2.969(5) Ag3 - Se2 2.664(5) Ag3 - Se3 2.702(7) Ag3 - Se6 2.619(6) Ag4 - Se3 2.593(7) Ag4 - SeS 2.670(7) Ag4 - Se6 2.663(7) Ag5 - Se2 2.681(9) Ag5 - Se4 2.939(7) Ag5 - Se5 2.659(9) Sel - Asl 2.421(9) Se2 - A82 2.451(9) Se3 - A82 2.408(9) Se4 - A83 2.389(7) Se5 - A83 2.450(9) Se6 - Asl 2.418(8) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {£n(ln - 1)2/n(n-l)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 258 Table 6-12. Selected Angles (Deg) in B-Ag3AsSe3 with Standard Deviations in Parentheses.“ Se4-Agl-Se4 99.5(2) Se4-Agl-Se6 131.0(2) Se4-Ag1-Se6 129.1(2) Sel-Ag2-Se1 102.1(2) Sel-Ag2-Se3 124.3(3) Sel-Ag2-Se4 107.3(2) Sel-Ag2-Se3 92.8(3) Sel-Ag2-Se4 115.8(3) Se3-AgZ-Se4 113.5(3) Se2-Ag3-Se3 109.4(3) Se2-Ag3-Se6 139.6(3) Se3-Ag3-Se6 110.3(2) Se3-Ag4-Se5 127.0(3) Se3-Ag4-Se6 132.3(3) Se5-Ag4-Se6 . 99.3(3) Se2-Ag5-Se4 107.3(3) Se2-Ag5-Se4 107.3(3) Se2-Ag5-Se5 119.9(4) Se4-Ag5-Se4 72.8(3) Se4-Ag5-Se5 120.0(3) Ag2-Sc1-Ag2 69.5(3) Ag2-Se1-Ag2 145.5(3) Ag2-Sel-Ag2 100.4(2) Ag2-Se1-Asl 113.2(3) Ag3-Se2-A82 86.0(3) Ag5-Se2-A82 96.8(4) Ag2-Se3-A82 97.8(3) Ag3-Se3-A82 112.8(3) Ag4-Se3-A82 94.9(3) Agl-Se4-As3 99.7(2) Ag2-Se4-As3 108.1(2) Ag4-Se5-A83 93.1(3) Agl-Se6-Asl 85.9(3) Ag3-Se6-Asl 89.2(3) Ag4-Se6-Asl 103.4(3) Sel-Asl-Se6 97.0(3) Se6-Asl-Se6 102.6(4) Se2-As2-Se3 100.0(3) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = {Zn(ln - 1)2/n(n-l)}1/2, where In is the length (or angle) of the nth bond, l the mean length (or angle), and n the number of bonds. 259 (A) A83 ‘82 Sel A31 s¢5 3‘3 Asl P A" ’ " A52 Se6 A23 5‘2 l . \ R. L \l J‘ I ‘T’ I l ‘ Figure 6-1. Structure and labeling scheme of Ag3AsSe3. (A) p-form. (B) a-form. 260 (B) 261 o J.‘ .2! J.‘ .l. 57 .2. ASK? p “logs; hi /t_.\’4l?.|vno‘=< . «I 4 . l 3‘5!‘ Ii" .52- 1| .‘ ‘AI .‘ 1.7 \O’ . V . I 'J.““-w-W' v - It. '1‘ A Figure 6—2. Stereoview of the B-Ag3AsSe3 (I). 262 (A) “1‘. Figure 6-3. Packing diagrams of p-Ag3ASSe3(I). (A) view down the b- axis. (B) Stereoview down the b-axis. (C) view down the c-axis. (D) Stereoview down the c-axis. 263 (B) 264 (C) 265 (D) '4‘ D .::.=‘.._. 1.99/"’; v' 4.. v. {It 7““..1?‘ $1,} '- El} "’4 """l'o to“ "a“:"o- . 266 more dense and thus could represent a high pressure modification of a-Ag3AsSe3, The compound (Me3NH)[AS3A828e5](II) was first synthesized by heating AgBF4 with K3AsSe3 and Me4NCl in H20 at 110 °C for one day. Although we started with Me4.N+ as the counterion, the presence of Me3NH+ cations was confirmed with infared spectroscopy. Other similar-sized organic cations were also tried, without success, in anticipation of obtaining the same anionic framework, an indication that the Me3NH+ ion was playing a templating role for compound (II). The anions [AS3ASZSeslnn' possess a very complicated two-dimensional layered structure consisting of tetrahedral Ag+ and [AszSe5]4' units formed by two corner-sharing trigonal pyramidal [AsSe3]3'; see Figures 6-4 and 6-5. Each of the [A828e5]4' units engages in a remarkably complex multidentate coordination with 11 Ag+ centers using all five of their selenium atoms; see Scheme 6-2. 118 A} 5 Ag Ag 5 r .-' A Ag—Se/ \Se/ g \ / AS\ e/AS\ / S _ \ A, | Ag A8 Scheme 6-2 267 The coordination geometry of the Ag(l) and Ag(2) atoms is distorted tetrahedral with the Se-Ag-Se bonds angles ranging from 85.9(1)° to 119.8(1)°. The average Ag-Se distance, at 2.725(5)A, is normal for tetrahedral Ag+ ions. The Ag(3) atom is coordinated to three Se atoms and the lone electron pair of an As atom. This is the first time we observed the lone pair of the As atom to be involved in metal binding. Recently, a similar bonding arrangement was also observed in KCu2ASS3 where Cu(l) and Cu(2) were tetrahedrally coordinated to three S atoms and the lone pair of an As atom. The Ag(3)-As distance is 2.844(4)A. The geometry of the Ag(3) can be described as either distorted trigonal planar, without the As atom, or distorted tetrahedral, with the As atom. Only one of the two As atoms in [A82Se5]4' is interacting with a Ag center. The average As- Se distance, at 2.410(4)A, and Se-As-Se angles, at 99.0(1) are normal compared to those in the known As/Se compounds.15 The shortest Ag-Ag distances are 2.889(5) and 3.012(3)A. Detailed distances and angles are summarized in Tables 6-13 and 6.14. The [Ag3AszSe5]nn' layers are formed in such way that all the lone pairs of the selenium atoms are pointed away from the layers. The trimethylammonium cations, Me3NH+, are located in the gallery region, yielding an interlayer distance of 11.47 A. Interestingly, the hydrogen atoms bonded to the nitrogen in the Me3NH+ ion point toward the layers, suggesting the presence of hydrogen bonding to the selenides, see Figure 6-6. The closest Se-H distances are Se(3)- H1 and Se(5)-H1 at 3.016A and 2.739A, respectively, which are much shorter than the van der Waals contact of 3.35 A. The Me3NH+ 268 Table 6-13. Selected Distances (A) (with Standard Deviations in Parentheses“) in the [Ag3A828e5]1’ layer. Agl - Ag2 3.012(3) Agl - Sel 2.713(4) Agl - Se2 2.650(4) Agl - Se3 2.830(4) Agl - Se5 2.722(4) Ag2 - Ag2 2.889(5) Ag2 - Se3 2.802(4) Ag2 - Se3 2.653(4) Ag2 - Se4 2.790(4) Ag2 - Se5 2.638(4) .Ag3 - Sel 2.611(4) Ag3 - Se2 2.620(4) Ag3 - Se5 2.770(4) Ag3 - A82 2.844(4) Sel - Asl 2.370(4) Se2 - A82 2.376(4) Se3 - Asl 2.369(4) Se4 - ASl 2.475(4) Se4 - A82 2.469(4) Se5 - A82 2.395(4) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation 01 = [2n(ln - 1)2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. Table 6-14. 269 Parentheses“) in the [Ag3AszSe5]1' layer. Selected Angles (Deg) (with Standard Deviations in Sel-Agl-Se2 108.6(1) Sel-Agl-Se3 85.9(1) Sel-Agl-SeS 116.7(1) Se2-Ag1-Se3 108.9(1) Se2-Ag1-Se5 119.8(1) Se3-Ag1-Se5 111.6(1) Se3-Ag2-Se3 116.1(1) Se3-Ag2-Se4 106.4(1) Se3-Ag2-Se5 115.2(1) Se3-Ag2-Se4 100.2(1) Se3-Ag2-Se5 113.0(1) Se4-Ag2-Se5 103.7(1) Sel-Ag3-Se2 124.7(1) Sel-Ag3-Se5 120.7(1) Sel-Ag3-A82 100.8(1) Se2-Ag3-Se5 93.2(1) Se2-Ag3-A82 119.7(1) Se5-Ag3-A82 95.0(1) Agl-Sel-Asl 94.2(1) Agl-Sel-A82 91.2(1) Ag3-Se2-A82 108.1(1) Agl-Se3-Asl 119.0(1) Ag2-Se3-Asl 108.2(1) Ag2-Se4-Asl 88.6(1) Asl-Se4-A82 110.9(1) Sel-Asl-Se3 100.1(1) Sel-Asl-Se4 96.3(1) Se3-Asl-Se4 102.9(2) Ag3-A82-Se2 116.2(1) Ag3-A82-Se4 139.6(1) Ag3-A82-Se5 99.5(1) Se2-A82-Se4 91.5(1) Se2-A82-Se5 98.5(1) Se4-A82-Se5 104.9(1) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {Zn(ln - l)2/n(n-l)]1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 270 (A) and labeling scheme of one [Ag3ASzSe5]' Figure 6-4. (A). Structure layer. (B) Stereov iew. (B) ' 271 272 (A) Se A8 As . Me3NH*———» , 0%‘0 Figure 6-5. Packing diagrams of (Me3NH)[Ag3ASZSe5](II). '(A) view down the c-axis. (B) view down the a-axis. 273 (B) 274 Figure 6-6. Packing diagram of (Me3NH)[Ag3ASZSe5](II) showing the hydrogen bonding between the Se and H. 27S cations may act as structure directing agents and cause this compound to form even in the presence of a very large excess of M e 4N + . Several attempts to perform ion -exchange with this compound did not succeed. The compound K5[Ag2AS3Se9](III) was prepared by heating a mixture of AgBF4 and K3AsSe3 in methanol at 110 °C for several days. Similar reactions with the other alkali metal salts of A3A8Se3 (A = Na, Rb) did not yield isostructural A5[Ag2A83Se9] compounds, indicating a templating role of K+. The [Ag2A838c9]n5n‘ macroanion has a unique two-dimensional layered structure with tetrahedral Ag+ ions and two different types of selenoarsenate ligands, [AsSe4]3' and [Aszse5]4'; see Figures 6-7 and 6-8. This [AszSe5]4° unit in (III) is different from the [A828e5]4' unit found in (Me3NH)[Ag3AszSe5](II). They are structural isomers. The [A828e5]4' unit In (111) can be viewed as the internal two-electron transfer (shown below) product of the [AszSe5]4' unit found in (Me3NH)[Ag3A828e5](II). The formal oxidation state of the four-coordinated As atom can be asigned as 4+ while the three-coordinated As atom is 2+. Kolis et al. have synthesized various arsenic selenides,16 including the discrete [A82Se5]4' in superheated ethylenediamine. Se The structure of [Ag2A83Se9]n5n' can be described as chains of [Angszseslz' linked by tetrahedral [AsSe4]3' units; see Figure 6-7. A 276 Table 6-15. Selected Distances (A) of K5[Ag2AS3Se9] with Standard Deviations in Parentheses.“ Ag ,- Se2 2.648(3) Ag - Se3 2.683(3) Ag - Se4 2.742(3) Ag - Se6 2.699(3) Sel - Asl 2.313(6) Se2 - As2 2.346(3) Se4 - Asl 2.340(3) Se5 - Asl 2.302(5) Se6 - As3 2.331(3) As2 - As3 2.580(5) K1 - Sel 3.329(6) K1 - Se2 3.321(7) K1 - Sc3 3.514(6) K1 - Se3 3.403(6) it: K1 - Se4 3.567(7) K1 - Se5 3.434 K1 - Se6 3.489(6) K2 - Sel 3.294(6) K2 - Se3 3.385(6) K2 - Se4 3.380(5) K2 - Se4 3.476(5) K2 - Se5 3.337(6) K2 - Se6 3.247(6) K2 - Se6 3.588(6) K3 - Se3 3.423(8) K3 - Se4 3.346(9) K3 - Se6 3.392(7) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {£n(ln - 1)2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 277 Table 6-16. Selected Angles (Deg) of [Ag2AS3Se9]5' with Standard Deviations in Parentheses.“ Se2-Ag-Se3 112.3(1) Se2-Ag-Se4 110.6(1) Se2-Ag-Se6 105.2(1) Se3-Ag-Se4 112.4(1) Se3-Ag-Se6 112.1(1) Se4-Ag-Se6 103.65(9) Ag-Se2-As2 93.3(1) Ag-Se3-A82 105.1(1) Ag-Se4-As1 114.5(1) Ag-Se6-As3 106.0(1) Sel-Asl-Se4 109.6(1) Sel-Asl-Se5 107.8(2) Se4-Asl-Se4 107.7(1) Se4-Asl-Se5 111.1(1) Se2-A82-Se3 105.9(1) Se2-A82-Se3 110.2(2) Se3-A82-Se3 111.3(1) Se3-A83-A82 98.2(1) Se6-A83-Se6 105.8(2) Se6-Se3-A82 98.2(1) “The estimated standard deviation in the mean bond lengths and the mean bond angles are calculated by the equation cl = [2n(ln - 1)2/n(n-l)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 278 Figure 6-7. Structure and labeling scheme of one [AngS3Se9]n5n' layer. 279 (A) Figure 6-8. Packing diagram of K5[Ag2AS3Se9]. (A) view down the a- axis. (B) view down the b-axis. 280 (B) 281 more descriptive formula of the compound would be [Ag2(A828e5)(AsSe4)]. A unique feature of this compound is its mixed-valent As3+lAs5+ character. The Ag+ ion is in a distorted tetrahedral environment with the Se-Ag-Se angles ranging from 103.65(9)° to 112.4(1)°. The average Ag-Se distance is normal at 2.693(3)A. The average As-Se distance in the As(III) unit (i.e. [AszSe5]4'), at 2.344(6)A, is slightly longer than that of the As(V) unit (i.e. [AsSe4]3'), at 2.318(6)A, as expected. The residual negative charge on the Se atoms leads to short K- Se distances due to the high electrostatic attraction. The geometry of seven-coordinated K(l) can best be described as trigonal prismatic with one of the faces capped by the seventh Se, see Figure 6-9. The K(1)-Se distances range from 3.321(7)A to 3.567(7)A. The K(2) atom is also seven-coordinated with a capped trigonal antiprismatic environment. The K(2)-Se distances range from 3.247(6)A to 3.588(6)A. The six-coordinated K(3) has a distorted trigonal prismatic geometry with the K(3)-Se distances ranging from 3.346(9)A to 3.423(8)A. The detailed bond distances and angles are summarized in Tables 6-15 and 6-16. The [AsSe4l3' only uses two of its four Se atoms to coordinate to Ag atoms and leaves the other two Se atoms as terminal selenides. The result of this bonding mode creates large 16 member rings where the K cations reside. K[Ag3A82S5](IV) was synthesized by heating various ratios of AgBF4, and K3A883 in methanol at 110 °C. Initial experiments in the A g/AsxSy system, with water as solvent always yielded the mineral 282 ll Figure 6-9. The coordination environments of K+ in KslAngS3Se9]. The open circles represent Se atoms. 283 proustite(Ag3AsS3). By simply changing the solvent from water to methanol we totally avoided the sulfosalt and obtained the new quanternary phase. The structure contains unique two-dimensional layers. Each layer has a very complicated structure consisting of formally Ag+ ions linked by a series of linear [AS387]5' units and pyramidal [ASS3]3' units; see Figures 6-10 and 6-11. Although the [A8387]5' units have been observed before in [InA83S7]2‘,1 the binding mode is totally. different in K[Ag3A8285](IV). In [InAS3S7]n2"‘, the [AS387]5' unit uses five of its terminal sulfur atoms to connect two In3+ centers, while in [Ag3AS285]n"‘, the [AsgS7l5' units are bonded to 10 Ag+ centers, see Scheme 6-3. A Ag\S/Ag\s/ g\S/Ag \ I / Agxs/ S/Ag / \ / \ Ag A8 Ag Ag Scheme 6-3 A more descriptive formula of the compound would be K2[Ag6(ASS3)(AS3S7)]. There are three kinds of Ag atoms in the lattice. The Ag(l) atom is in a distorted tetrahedral geometry with the S-Ag-S angles ranging from 101.5(2)° to 118.0(2)° while the Ag(2) and Ag(3) atoms are trigonal-planar coordinated to three S 284 atoms. The Ag(2) atom is more distorted than that of the Ag(3) atom with S-Ag(2)-S angles that range from 100.9(2) to 155.1(1)°. The S- Ag(3)-S angles range from 110.8(2)° to 125.8(2)°. The distortion is probably due to the ligand constrain. The average tetrahedral Ag(l)- S distance, at 2.638(6)A, is longer than the expected average trigonal-planar Ag(2)-S and Ag(3)-S distances of 2.558(7)A and 2.498(6)A, respectively. The average As-S distances and S-As-S angles are normal at 2.268(6)A and 99.5(2)°.17 The K atom is seven- coordinated with the K-8 distances ranging from 3.150(8)A to 3.522(8)A. The coordination environment of K is irregular and can best be described as a capped trigonal antiprism, see Figure 6-12. Detailed distances and angles are summarized in Tables 6-17 and 6- 18. 285 Table 6-17. Selected Distances (A) in K[Ag3A8285] with Standard Deviations in Parentheses.“ Agl - Ag2 2.996(3) Agl - Ag2 3.139(3) Agl - 82 2.620(6) Agl - S3 2.758(6) Agl - SS 2.624(6) Agl - S6 2.550(6) Ag2 - 82 2.568(7) Ag2 - SS 2.538(7) Ag2 - SS 2.569(7) Ag3 - 8] 2.461(6) Ag3 - 82 2.488(6) Ag3 - S3 2.545(6) Asl - 8] 2.238(9) Asl - 82 2.255(6) As2 - S3 2.246(6) A82 - S4 2.307(6) A82 - SS 2.252(6) As3 - S4 2.317(6) A83 - S6 2.231(8) K - Sl 3.150(8) K - $2 3.413(8) K - S3 3.299(8) K - S3 3.522(8) K - S4 3.269(8) K - S4 3.395(8) K - S6 3.302(9) “The estimated standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {£n(ln - l)2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, l the mean length (or angle), and n the number of bonds. Table 6-18. Selected Angles (Deg) in the [Ag3A8285]1' ion with 286 Standard Deviations in Parentheses.“ S2-Ag1-S3 118.0(2) sz-Agl-ss 104.9(2) sz-Agl-So 116.3(2) S3-Ag1-85 102.2(2) S3-Ag1-S6 101.5(2) SS-Agl-S6 113.3(3) r S2-Ag2-SS 103.0(2) S2-Agl-SS 100.9(2) 3. SS-Agl-SS 155.1(1) Sl-Agl-SZ 122.4(2) J: Sl-Ag3-S3 125.8(2) sz-Ag3-S3 110.8(2) a Sl-Asl-S2 98.2(2) S1-ASl-S2 98.2(2) " S2-Asl-82 104.6(4) S3-As2-S4 103.9(2) S3-A82-SS 101.9(2) S4-A82-SS 99.1(2) S4-As3-S4 88.2(3) S4-As3-S6 100.6(6) S4-A83-S6 100.6(6) Ag3-Sl-Asl 101.1(2) Agl-SZ-Asl 90.1(2) Ag2-$2-Asl 105.1(2) Ag3-S2-Asl 131.9(3) Agl-S3-A82 106.3(2) Ag3-S3-A82 93.5(2) A82-S4-As3 102.4(2) Ag2-SS-A82 96.8(2) Ag2-S5-A82 97.7(2) £S6-As3 100.353) “The estimated Standard deviations in the mean bond lengths and the mean bond angles are calculated by the equation cl = {2n(ln - 1)2/n(n-1)}1/2, where In is the length (or angle) of the nth bond, I the mean length (or angle), and n the number of bonds. 287 (A) 83 A82 SS $1 55 A82 II Figure 6-10. (A) Structure and labeling scheme of one [Ag3A8285]nn' layer. (B) Stereoview. 288 (B) 289 (A) Figure 6-1 1. Packing diagram of K[Ag3A8285]. (A) view dOwn the b- axis. (B) view dow'n the c-axis. 290 (B) K e. s .... ., .:.E. M O :.. a; . fiel'x fil.lmf‘wprs ! I‘»‘\ M ..\’l‘\p"\ A As..m e4 1%. 0V. w! .\ / an: _ v .5446? x. 65 V . . fin A o H‘S’..irn.\km....‘, .‘48 ,. o in! .4 l. .85... . _ ”a. O 291 o 0 Figure 6-12. The coordination environments of K+ in 1([Ag3A82851 The open circles represent-S atoms. 292 3.2 Physicochemical studies In the far-IR -region complexes (I)-(III) exhibit spectral absorptions due to AS-Se and Ag-Se stretching vibrations while complex (IV) Show spectral absorptions due to As-S and Ag-S stretching vibrations; see Figures 6-13 and 6-14. Observed absorption frequencies of all the complexes are given in Table 6.19. Table 6.19. Frequencies (cm° 1) of Raman and Infrared Spectral Absorptions of B-Ag3AssSe3 (I), (Me3NH)[Ag3AS28e5] (II), K5[Ag2AS3Se9] (III), and K[Ag3A82S5] (IV). Compounds Infrared Raman B-Ag3ASSC3 246(8, br), 232(8) 243(8), 209(m), 167(m) 171(m), 157(m) _ 142(m), (Me3NH)[Ag3A82$e5] 269(s), 258(8) 273(8), 260(8), 246(m) 248(8. sh), 219(8) 234(w), 215(m), 175(w) 161(m, br) K5[Ag2AS3SCg] 293(8, 811), 282(8) 294(m), 272(m), 265(m) 264(m), 242(w) 236(m), 210(8), 178(m) 177(m, br), 155(m) K[Ag3A82$5] 336(8, br), 252(m) 373(8), 336(m), 317(m) 247(m),190(w) 218(m, br). 225(m), 205(m) * 8: Strong, 111; medium, w: weak, sh: shoulder, br : broad. X 1W3"! TTMCE 293 A A (A) 7" (B) Figure 6-13. Far-IR spectra of (A) B-Ag3ASSe3, (B) (Me3NH)[Ag3A828e5]. 294 (A) X TWITTMCE (B) sea «to :66 sin :60 :60 260166730 HAVENLHBEH Figure 6-14. Far-IR spectra of (A) K5[Ag2AS3Se9], (B) and KIA83A82551- 295 In the Far-IR spectra of B-AggAsSe3 (I), (Me3NH)[Ag3A82$e5] (II), and K5[Ag2A83Se9] (III), the peaks in the region of 200-300 cm'1 could be attributed to As-Se vibration modes. Similar assignments have been made in the far-IR spectra of other known thioarsenic complexes.18 In addition, a medium-intensity band around 170-150 cm“1 was found in all compounds. This might result from an Ag-Se stretching vibration. The Far-IR spectrum of K[Ag3A82S5] (IV) showed a strong-intensity broad band at around 340 cm'1 and a weak-intensity band at 250 cm'l. The former can be assigned to an As-S stretching vibration19 while the latter might be due to a Ag-S stretching vibration. The major difficulty in assigning correctly the observed IR spectra of these compounds arises from the fact that As- Q and Ag-Q (Q = S, Se) stretching frequencies fall in the same low frequency region of 150-350 cm'l, The Raman spectra of (I), (II), (III) and (IV) were also recorded. In (I), (II), and (III) the peaks in the region of 200-300 cm“1 could be assigned to AS-Se vibrations while the lower energy peak around 170 cm‘1 could result from Ag-Se vibrational modes. A similar assignment for (IV) can be applied to the Raman spectrum as was done for its Far-IR spectrum. The optical properties of compound (I) - (IV) were assessed by Studying the UV/near-IR reflectance spectra of the materials. The spectra confirmed they are semiconductors by revealing the 296 A 0.15 l 1 L 1 l 1 '5 (A) .6 5; 0.1- ~ 8 g AglAsSes E- 0.0S- Eg-1.$eV - .91 a g J’J 0") I I I I I I eV A 35 1 A 1 1 J l 3 3‘ H) ‘ .o' g 2.5- - E g 2-1 .- g 1 .5 _ (Me3NH)[Ag3As 2595] b g Eg-l.8ev 9' 1- 1— 8 ‘3 05- - g . 0 1 I I T I I 0 1 2 3 4 5 6 7 eV Figure 6-15. Optical absorption spectra of (A) B-Ag3AsSe3(I) and (B) (Me3NH)[Ag3A82Se5](II). tufl 297 0.25- 0.2- 0.15‘ 0.1— 0.05 - 5 a/S absorption Coeff. (arb. units) 0.3 l I L 1 l 1 0.25-1 (B) K[Ag3A $255] a/S absorption Coeff. (arb. units) .0 3‘. l 0.] .1 Eg-2.4 eV - 0.05 d ' 0 - I I I I O 1 Z 3 4 S 6 7 eV Figure 6—16. Optical absorption spectra of (A) K5[AngS3Se9](IlI) and (B) KIA83A82$5](IV). 298 30 L ‘ 1 ‘ 25- (A) " L. emu 20- U 15- * nv 101 7 fl 5- ' endo 0.. _ __ - '5 I 1 I 1 0 100 200 300 400 500 Temp('C) 30 I 1 I I eno 20- . 1 _ "v 10" 1- fl 5" b endo 0.. _- _ .. I I I I 0 I 00 200 300 400 500 Temp (°C) Figure 6-17. DTA data of B-Ag3AsSe3(I). (A) First cycle. (B) Second cycle 299 105 ' L ‘ 100 9 "T )- 95 7 r g 90 1 . 3 85 - t 80 9 l. 75 . L 70 r r r 0 200 400 600 800 Temp (‘C) Figure 6-18. TGA diagram of B-Ag3AsSe3(I). 300 110 . ' ‘ 100- —\ . 90- 80- ' 70- . 60- i 50- “ 40 W06) I 0 200 400 600 800 T311113 (°C) Figure 6-19. TGA diagram of (Me3NH)[Ag3A82Se5]. 301 presence of Sharp optical gaps as shown in Figures 6-15 and 6-16. The bandgaps are 1.5, 1.8, 1.7, and 2.4 eV, respectively. An (othv)2 vs. E plot in the 1.5 to 1.7 eV region of the spectrum of B-AggAsSe3 gives a linear section, see figure 6-15, which suggests the presence of a direct band-gap in this material. It is tempting to suggest that the sharp absorption feature in the spectrum is excitonic in origin, but additional experiments would be required to prove this. The 1.5 eV band-gap of B-Ag3AsSe3 lies in the optimal region for efficient absorption of solar radiation, which coupled with the three- dimensional structure of this material, suggests that it may possess significant photoconductivity. The thermal behavior of B-Ag3ASSe3 was investigated with differential thermal analysis (DTA), see Figure 6-17. The DTA thermogram, first cycle, showed a melting point, at 396 °C, and a crystallization point, at 342 °C. A second cycle, revealed two melting points, at 391 °C' and 396 °C, and the same crystallization point, at 342 °C. The XRD of the DTA residue indicated that B-Ag3AsSe3 transformed into the known a-Ag3AsSe3 with Ag28e as a minor product. This observation was also comfirmed by the TGA experiment where B-Ag3AsSe3, see Figure 6-18, started to lose mass around 250 °C to give Ange. The thermal stability of (Me3NH)[Ag3A82Se5] (II) was studied by thermal gravimetric analysis (TGA). There are two weight loss steps in the temperature range of 140-200 and 430-770 °C; see Figure 6-19. (Me3NH)[Ag3AS2Se5] loses its organic cations as Me3N and ste in the first step. The layer integrity, however, is not 302 maintained and the products at the end of the first weight loss were found to be, by X-ray powder diffraction, a mixture of a-Ag3AsSe3 and AgAsSez. The second weight loss corresponds to the loss of AszSe3 and the final decomposition product is pure Ag28e(Ag2Se- 120, naumannite)20 by X-ray powder diffraction. The final weight loss observed from the TGA diagram was in excellent agreement with the theoretical value. In conclusion, the synthesis of new ternary and quaternary compounds, B-Ag3AsSe3 (I), (Me3NH)[Ag3A82Se5] (II), K5[Ag2A838e9] (III), and K[Ag3A8285] (IV), has proven that the hydro(solvo)thermal technique is a very powerful yet simple synthetic route to new silver arsenic sulfide and selenide compounds. The isolation of B-AggAsSe3, alone, implies that there are more new low temperature phases, in sulfosalts, waiting to be discovered and chemists should take another look at this alternative synthetic route. 10 11. 303 REFERENCES Chou, J.-H.; Kanatzidis, M. G. Inorg. Chem. 1994,33, 1001-1002. Chou, J.-H.; Kanatzidis, M. G. Chem. Mater. 1995, 7, 5-8. Chou, J.-H.; Kanatzidis, M. G. Inorg. Chem. 1994, 33, 5372-5373. Sheldrick, W. S.; Haiisler, H.-J. Z. Anorg. Allg. Chem. 1988, 55 7, 98-104. Sheldrick, W. S.; Haiisler, H.-J. Z. Anorg. Allg. Chem. 1988, 55 7, 105-1 1 1. Sheldrick, W. S.; Haiisler, H.-J. Z. Anorg. Allg. Chem. 1988, 561 , 139-148. Sheldrick, W. S.; Haiisler, H.-J. Z. Anorg. Allg. Chem. 1988, 561 , 149-156. Sheldrick, W.; Kaub, J. Z. Anorg. Allg. Chem. 1986.535, 114- 1 l8. Sheldrick, W.; Kaub, J. Z. Anorg. Allg. Chem. 1986, 535, 179- 185. O'Neal, S. C.; Pennington, W. T.; Kolis, J. W. J. Am. Chem. Soc. 1991, 113, 710-71'2. O'Neal, S. C.; Pennington, W. T.; Kolis, J. W. Inorg. 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B. H.; Gillespie, R. J.; Sawyer, J, F, Inorg. Chem. 1981, 20. 3410-3420. 19. (a) Mohammed, A.; Miiller. U. Z. Anorg. Allg. Chem. 1985.523, 45-53. (b) Sinning, H.; Muller, U. Z. Anorg. Allg. Chem. 1988, 564, 37-44. 305 20. JCPDS International Center for Diffraction Data. Powder Diffraction File 24-1044. 306 CHAPTER 7 CONCLUSIONS 307 In this work we have developed the hydro(solvo)thermal method for making various metal/Asty (Q = S. Se) compounds. Although the hydro(solvo)thermal technique has been known for many years. the current interest of applying this technique to inorganic synthesis is focused on solid state compounds.l We hope our work will change the misconception that hydro(solvo)thermal chemistry is applicable only to metal oxides, silicates, etc.2 The remarkable feature exhibited by the compounds described in this dissertation is the complex condensation reactions exhibited by the thioarsenate and selenoarsenate polyanions.(see eq 1-4) AsstHZ' + AsS,SH“' z: [A8285]" + H28 (Eq. 1) [A8285]" + 1128 z: [As2848H13' + HS" (Eq. 2) [As,S,SH]3' + AsstHz' = [As,s.,]5° + H28 (Eq. 3) [As3s7ls' + H28 3:: [As,S,SH]" + H8“ (Eq. 4) These condensation reactions were probably catalyzed by the protonation of the terminal sulfur groups. The list of various [Asty]n' (Q = S. Se) polyanions found in this work is shown in Tables 7-1 and 7-2. Their structures and their bonding modes are shown in Tables 7-3, 7-4, and 7-5. Table 7-1 Various 308 [AsnSyln' polyanions. _L_igand Solvent Compound [AsS3]3' methanol K2[Ag5(AsS3)(AS3S7)] [AsS4]3' water, methanol (Ph4P)2K[M3(AsS4)3] (M=Pt, Pd) [A828514' water (Me4N)2[M0202(A8285)821 [A8385l3' water (Ph4P)2[Pt(AS3S§)2] [AS386]3" water (Me4N)2Rb[Bi(AS3S6)2], (Me4N)[HgA83S5] [A8387]5' water. methanol K2[Ag5(ASS3)(A83S7)], (Ph4)2[1nAS3S7] [A848 3]4' w a ter (Ph4P)2[NiAS4S 3] [AS4S9l6' water (Ph4P)2[H82AS4S9L (Ph4lflz[SnA8489] Table 7-2 Various [AsxSeyP' polyanions. Ligand Solvent Compound [AsSe3]3' water (Me4N)[HgASSe3], (Et4N)[HgAsSe3] [A828e5]4‘ a water (Me3NH)[Ag3A828e5] [A828e5]4' b methanol K5[Ag2AS3Se9] [AS4Se11]6' w ater (Ph4P)11;I_ng84Se11] 309 Table 7-3. Various [AstyPl' (Q = 8, Se) anions found in this work. 3_ As," lAstI Q/ (I n S: 3- 't' [A8864] Se / \Se 3. if.“ [Assn s/ g “843 . As. A!“ [A82Q5J4 Q/ A "’0’ 6 "Q As 3- 5’ ‘5 [A3335] 18 A7" s\‘ . \s/ ”’3 i If. [AS386]3- 8’ ‘3 I. I, s\“ \S/ "'15 _ A8 A8. A! [A83S715 s j ”8’ ‘ "’s" ”S S S S A , A , 4- s/ As "’8’ Is "’5 s [A5433] 8 S. A S ' \ "/As “\ \As "a A8, A8, A5. A8. [As48916‘ s/ I "’3’ I "’3’ I "45’ ‘ 9,8 s s S s As A8 A8 A, - ”I ’ .9 / o.” O'I [A848en]6 s°/S’ 3° 88 ’3‘ s1 “’4 9° Se/ \Se 8 s l. 1'. 311 s/ \1 ? 8’ ‘1 :1 [As S ] ' ' A. A: At A8 A: 36a /~\Sl)§/4\/4\/~\sl \/g\ s—As; s—M/ 310 Table 7-4. Different binding modes found in the [AstyP' anions. [AsSe313' A8 A8 A8 A8 A s/ \ Se/ 3\ /A /A8 Se Se Ag)°\/s c-VAg A \A' /s°"Ag Al'seA'\ 8€>$7Ag Hg/ \As/ \HB A! A! :1" Ag A l 8L a" ° "Ms / \ /"°\ / AA8’3I \Ag AgA' A8 Ag AI8 A8 Hg [AS38715- AKS\/::\?/A‘\/)g /S A x S\ /As—S\ ’As “/3, In \ S I AK/s/N /1/“ \MKAMs \s/ 0 Ag/ \Ag Ag /\8 S/ [AS43916- S / )s/Sx MISNP/