Optically active vinyl polymers containing fluorescent groups. 8. Synthesis and properties of copolymers of N-vinylcarbazole and (-)-menthyl acrylate and (-)-menthyl methacrylate

N-Vinylcarbazole was free radically copolymerized with (-)-menthyl acrylate and (-)-menthyl methacrylate in benzene at 55 "C to give optically active copolymers characterized by a marked induced optical rotation in the heteroaromatic co-units. Electronic absorption and emission properties, and the estimated reactivity ratios, are entirely consistent with quasi-random copolymerizations with, however, a tendency to alternation, especially for the N-vinylcarbazole unit. In contrast to the known behavior of copolymers of chiral monomers with other vinylaromatic monomers, the differential dichroic absorption exhibits a maximum value for copolymers containing approximately 40 mol % N-vinylcarbazole units. A similar maximum has been noted previously for copolymers of N-vinylcarbazole with (-)-menthyl vinyl ether and confirms the unique value of carbazole units as probes for asymmetric induction in polymer chains.