Abstract
Polyethylenes and highly syndiotactic poly(propylene)s possessing chain end hydroxyl groups were synthesized by living polymerizations using L~2~TiCl~2~ [1, L: C~6~F~5~NCH(2OC~6~H~3~3^t^Bu)]/MAO and functionalized α‐olefins, H~2~CCH(CH~2~)~n~Y [2; YOAlMe~2~, n = 4 (2a); YOSiMe~3~, n = 9 (2b)]. Because the primary insertion of 2 to a cationic species L~2~Ti^+^Me (3) derived from 1/MAO is much faster than the successive secondary insertion of 2, addition of an equimolar amount of 2 to 3 resulted in the quantitative formation of L~2~Ti^+^CH~2~CH(Me)(CH~2~)~n~Y [4; YOAlMe~2~, n = 4 (4a); YOSiMe~3~, n = 9 (4b)]. These cationic species 4 served as functionalized initiators for the living polymerization of both ethylene and propylene and afforded polyolefins having extremely narrow molecular weight distributions and a hydroxyl group at the initiating chain end. The terminating chain end of the syndiotactic poly(propylene)s was also functionalized by adding an excess amount of 2b as a chain end capping agent to the living L~2~Ti–polymeryl species. Due to much slower insertion of the second molecule of 2b relative to the first one, the obtained polymers were end capped quantitatively by a single molecule of 2b. Telechelic syndiotactic poly(propylene)s were successfully synthesized through a living polymerization initiated by 4b and an end capping using 2b.
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