Systematic Investigation of Optical and Chiroptical Properties of Chiral π‐Conjugated Oligomers in Solution and Thin Films

Four families of structurally related chiral pi-conjugated oligomers bearing a hydroquinone (HQ), 1,5-dihydroxynaphthalene (Naph), benzo[1,2-b:4,5-b']dithiophene-4,8-diol (BDT) or 9H-carbazole (CBZ) central core, for a total of 11 new compounds, have been synthesized by simple and versatile synthetic strategies involving Pd-catalyzed cross-coupling protocols: a Suzuki-Miyaura reaction, a Sonogashira/desilylation/Sonogashira sequence or a Sonogashira/desilylation/acyl Sonogashira sequence. A systematic investigation of the optical and chiroptical features of the final chiral dyes was performed in chloroform solution and on spin-coated thin films. The ECD investigation was crucial in revealing that, even within the same family of organic dyes, minor variations in the nature and length of the pi-conjugated backbone can result in very different solid-state arrangements at different hierarchical scales.A systematic investigation of four different families of structurally-related chiral pi-conjugated oligomers, prepared by synthetic strategies involving Palladium-catalyzed cross-coupling protocols, was performed in chloroform solution (absorbance, photoluminescence) and spin-coated thin films (absorbance, photoluminescence, ECD, optical microscopy).