Asymmetric polymerization of N-vinylcarbazole with optically active anionic initiators

The anionic polymerization of N -vinylcarbazole (NVC) by using optically active anionic initiators such as the lithium salts of ( S )-1-(9H-fluoren-2-yl)-4-isopropyl-4,5-dihydrooxazole (( S )-1-FIDH) and ( S )-2-(9H-fluoren-2-yl)-4- isopropyl-4,5-dihydrooxazole (( S )-2-FIDH) and complexes of (-)-Sparteine with n -butylithium (n-BuLi-(-)-Sp) or fluorenyl lithium (FILi-(-)-Sp) was achieved. The yield and specific rotation of poly( N -vinylcarbazole)s (poly(NVC)s) were considerably affected by the molar ratio of ( S )-FIDH to NVC. The highest yield and specific rotation were obtained with Li- ( S )-1-FIDH as an initiator, with a molar ratio of monomer and initiator [M]/[I] = 10/1. The effects of the chiral initiators, type of solvent and the polymerization temperature were investigated. The obtained optical activity of polymers was attributed to asymmetric induction of the chiral initiators.