Metallocene/Borate-Catalyzed Polymerization of Amino-Functionalized α-Olefins

Cationic metallocene/borate catalysts, generated from zirconocene dimethyl compounds, L n ZrMe 2, and anilinium borate, [HNMe 2 Ph] + [B(C 6 F 5 ) 4 ] -, were used to polymerize 5-amino-1-pentenes and one 4-amino-1-butene with dimethyl, diethyl, diisopropyl, or diphenyl substitution patterns on nitrogen. The monomer 5-( N, N -diisopropylamino)-1-pentene showed the highest activity with Cp* 2 ZrMe 2 /borate and was used for all further investigations. The catalytic system Cp* 2 ZrMe 2 /borate was 4 times more active than the corresponding methylaluminoxane-based system and 180 times more active than the heterogeneous system, TiCl 3 /Al( i -Bu) 3 . 1-Hexene and 5-( N, N -diisopropylamino)-1-pentene were polymerized with Cp* 2 ZrMe 2 and rac -ethylenebis(tetrahydroindenyl) zirconium dimethyl, rac -EB(THI)ZrMe 2 . Polymerization of both monomers with Cp* 2 ZrMe 2 displayed similar activities. Hexene polymerizations with rac -EB(THI)ZrMe 2 were 30 times more active than those with aminopentene. 5-( N, N -Diisopropylamino)-1-pentene polymerizations gave rise to isotactic poly(aminopentene) with C 2 symmetric catalysts, syndiotactic polymer with a C s symmetric catalyst, and atactic polymer with achiral catalyst precursors.