Synthesis, characterization and photoconductive properties of optically active methacrylic polymers bearing side-chain 9-phenylcarbazole moieties

Abstract

The synthesis of two novel optically active monomers containing 9-phenylcarbazole moieties, such as ( S)-(+)-2-methacryloyloxy- N-[4-(9-carbazolyl)phenyl]succinimide [( S)-(+)- MCPS] and ( S)-(+)-3-methacryloyloxy- N-[4-(9-carbazolyl)phenyl]pyrrolidine [( S)-(+)- MCPP], is described. Each monomer has been radically homopolymerized to afford the corresponding optically active polymeric derivatives, which have been fully characterized. Their spectroscopic, thermal and photoconductive properties were compared to those of the new achiral homopolymer poly[ N-(2-methacryloyloxyethyl)- N-[4-(9-carbazolyl)phenyl]ethylamine] {poly[ MCPE]}, devised as an optically inactive macromolecular model compound, as well as to analogue polymeric derivatives containing side-chain optically active carbazolyl moieties. The chiroptical properties of the chiral polymers are quantitatively higher than in the corresponding monomers. Owing to the substantially stereoirregular structure of the main chain, this suggests that the overall optical activity is mainly due to conformational dissymmetry of the macromolecules. Spectroscopic evidence suggests the presence in all polymeric derivatives of dipole–dipole interactions between the 9-phenylcarbazolyl chromophores, occurring as a consequence of their anchorage to the polymer backbone, which favours their aggregation and justifies their high decomposition temperatures.