Cross Conjugated Oligomers / Abstract

cross conjugated oligomers and polymers

We have made a substantial synthetic effort toward developing methods suitable for the synthesis of cross-conjugated enyne oligomers. This includes, for example, the first syntheses of two new classes of oligomers, the iso-polydiacetylenes (iso-PDAs, 1) and iso-polytriacetylenes (iso-PTAs, 2), the cross-conjugated constitutional isomers of polydiacetylenes and polytriacetylenes, respectively. Throughout these studies, we have sought to answer several fundamental questions: 1) Is the synthesis of monodisperse, enyne oligomers viable? 2) Are these oligomers stable? 3) Can we determine the extent of electronic communication via cross conjugation? 4) Can cross conjugation be used to provide fully conjugated polymers with significant transparency to function as nonlinear optical or electroluminescent materials? Several series have been realized, examples of which shown below, and these studies have established the viability of cross-conjugated compounds as organic materials.

The third-order nonlinear optical properties of these monodisperse oligomers with phenyl substituents, have been investigated and show a surprising increase in nonlinearity as a function of length. More recently, the prospect of chiral, conjugated "foldamers" derived from iso-PDAs has become a major focus of this work, as these unique oligomers will almost certain display exciting optical properties, such as polarized emission. The proposed helical conformation is shown in below for the tridecamer.