Chiral ethylhexyl substituents for optically active aggregates of pi-conjugated polymers

An efficient synthesis route was developed to obtain chiral (2S)-ethylhexanol which was then used for functionalization to improve soly. of polythiophene conjugated polymers. The .alpha.-substituted chiral ethylhexyl side chains were obtained through a powerful and flexible asym. synthesis using pseudoephedrine as a chiral auxiliary. The dependence of the properties of conjugated polymers on mol. structure was studied by CD, fluorescence, and absorption spectroscopy on two chiral conjugated polymers, poly(3,3-bis((S)-2-ethylhexyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine) (PProDOT((2S)-ethylhexyl)2) and poly(3,3-bis((S)-2-methylbutyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine) (PProDOT((2S)-methylbutyl)2). The properties of PProDOT((2S)-ethylhexyl)2 differ significantly from those of its methylbutyl analog as studied by chiral aggregation providing insight into the role of interchain interactions in these subsecond switching electrochromic polymers