Syndiospecific coordination (Co)polymerization of carbazole-substituted styrene derivatives using the scandium catalyst system

The syndiospecific coordination polymerization of carbazole-substituted styrene derivatives (9-(4-vinylbenzyl)-9H-carbazole (FSt1), 9-(4′-vinyl-[1,1′-biphenyl]-4-yl)-9H-carbazole (FSt2), 3-bromo-9-(4-vinylbenzyl)-9H-carbazole (FSt3) and 3,6-dibromo-9-(4-vinylbenzyl)-9H-carbazole (FSt4)) was successfully achieved using a rare-earth metal catalyst (C5Me4SiMe3)Sc(CH2SiMe3)2(THF). The catalyst system showed high activity and excellent syndioselectivity for the polymerization of FSt. Representative photophysical properties such as UV-vis absorption and fluorescence spectroscopy of the homopolymers with high syndiotacticity have been characterized. Then the copolymerization of FSt with styrene was achieved using this catalyst system. The insertion rate of carbazole-substituted monomers could be adjusted simply by changing the feed amount. Strikingly, the copolymers had gradient sequence distributions confirmed by 13C NMR spectrum analysis and a kinetics study.