Metallocene/borate-catalyzed polymerization of amino-functionalized α-olefins

Cationic metallocene/borate catalysts, generated from zirconocene dimethyl compounds, LnZrMe2, and anilinium borate, [HNMe2Ph](+)[B(C6F5)(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*ZrMe2/borate and was used for all further investigations. The catalytic system Cp-2*ZrMe2/borate was 4 times more active than the corresponding methylaluminoxane-based system and 180 times more active than the heterogeneous system, TiCl3/Al(i-Bu)(3). 1-Hexene and 5-(N,N-diisopropylamino)-1-pentene were polymerized with Cp-2*ZrMe2 and rac-ethylenebis(tetrahydroindenyl) zirconium dimethyl, rac-EB(THI)ZrMe2. Polymerization of both monomers with Cp-2*ZrMe2 displayed similar activities. Hexene polymerizations with rac-EB(THI)ZrMe2 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.