I. A covalent/computational approach for sensing chirality. II. Oxidative functionalization of the indole core. III. Design and synthesis of novel cyanine dyes as photoreceptors for photovoltaics

ABSTRACTI. A COVALENT/COMPUTATIONAL APPROACH FOR SENSING CHIRALITY II. OXIDATIVE FUNCTIONALIZATION OF THE INDOLE CORE III. DESIGN AND SYNTHESIS OF NOVEL CYANINE DYES AS PHOTORECEPTORS FOR PHOTOVOLTAICSByJun Zhang In the first part, a simple and efficient protocol for sensing the absolute stereochemistry and enantiomeric excess of chiral monoamines is described. Preparation of the sample requires a single-step reaction of the 1,1′-(bromomethylene)dinaphthalene with the chiral amine. Analysis of the exciton coupled circular dichroism (ECCD) generated from the derivatized chiral amine sample, along with comparison to conformational analysis performed computationally, yields the absolute stereochemistry of the parent chiral monoamine. Expansion of this methodology also leads to the absolute stereochemical determination of chiral carboxylic acids. In the second part, a tunable reaction between 3-oxindole formation and selective C-H oxidation or amination under a mild condition is described. Substituted alkyl position on the indole directs the reaction to different pathways under similar conditions. Mechanistic studies reveal the oxidation cycle of Cu(I)/Cu(II), hydroxylamine and air play different roles in this reaction. In the third part, a simple method to tune the Stokes shift of heptamethine cyanine dyes is introduced. After various computational studies, we were able to build a theoretical model to predict the photophysical properties of cyanine dyes. Cyanine analogs were synthesized as fluorophores for luminescent solar concentrators (LSCs) to harvest solar energy. The absorption range of the synthesized dyes were from 600 nm to 780 nm, with Stokes shift as large as 180 nm.