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Keywords:

  • alternating copolymerization;
  • ethylene;
  • isobutylene;
  • limonene;
  • metallocene catalysts;
  • modified methylaluminoxane

Abstract

A series of titanium complexes with ansa-(fluorenyl)(cyclododecylamido) ligands, Me2Si(η3-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 η3-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(η3-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. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013