Steering the Conformation and Chiroptical Properties of Poly(dithienopyrrole)s Substituted with Chiral OPV Side Chains.

摘要

This manuscript discusses the conformation and chiroptical properties of poly(dithienopyrrole)s (PDTPs), Substituted with oligo(phenylenevinylene) (OPV) side chains and the influence of the substitution of the OPV moiety on these features. The OPV side chains were equipped with gallic acid moieties in order to promote the formation of a helical conformation in poor solvents. The polymers were prepared by Stille-couplings and characterized by GPC and NMR, UV-vis, CID, and emission spectroscopy. It was found that OPV-PDTPs, solely equipped with (chiral) alkyl groups at the terminal gallic acid group, show a very strong tendency to adopt a helical conformation, but no resolution or the mixture of helices and therefore no chiral expression. Additional substitution of the allows for a discrimination of the mixture of lielical senses. In this way, the OPV side chains can bechirally organized by the helical PDTP backbone. Substitution of the OPV in a-position, however, sterically excludes the possibility to adopt a helical conformation, but results in a lamellar supramolecular Structure in poor solvents. The macromolecular behavior is explained in terms of space confinement and sieric hindrance in the respective Structures.