Copolymerization of ethylene with 1,1-disubstituted olefins catalyzed by ansa-(fluorenyl)(cyclododecylamido)dimethyltitanium complexes

A series of titanium complexes with ansa-(fluorenyl)(cyclododecylamido) ligands, Me2Si(?3-R)(N-c-C12H23)TiMe2 [R = fluorenyl (5), 2,7-tBu2fluorenyl (6), 3,6-tBu2fluorenyl (7)], was synthesized. The crystal structure of complex 6 revealed 3-coordination of the fluorenyl moiety to the metal. Upon activation with trialkylaluminum-free modified methylaluminoxane, complexes 57 as well as the corresponding tBu amide complexes, Me2Si(?3-R)(NtBu)TiMe2 [R = fluorenyl (2), 2,7-tBu2fluorenyl (3), 3,6-tBu2fluorenyl (4)], were adopted as the catalysts for the copolymerization of ethylene (E) and isobutylene (IB). Among these complexes, complex 6 was found to achieve the highest IB incorporation to produce alternating E-IB copolymers. Complex 6 system also achieved copolymerization of E and limonene. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013