Ni(II) and Pd(II) complexes bearing benzocyclohexane-ketoarylimine for copolymerization of norbornene with 5-norbornene-2-carboxylic ester

Abstract

A serial of late transition metal complexes, which bearing Benzocyclohexane-ketoarylimine ligand and named as Mt(benzocyclohexane- ketoarylimino) 2 {Mt(bchkai) 2: Mt=Ni or Pd; bchkai=C 10H 8(O)CN(Ar)CH 3; Ar=naphthyl or fluoryl}, have been synthesized and characterized. The molecular structures of the ligands and nickel complex have been confirmed by X-ray single-crystal analyses. The nickel complexes exhibited very high activity up to 2.7 × 10 5 g polymer/mol Ni·h and palladium complexes showed high activity up to 2.3 × 10 5 g polymer/mol Pd·h for norbornene (NB) homo-polymerization with tris(pentafluorophenyl)borane as cocatalyst. The four complexes were effective for copolymerization of NB and 5-norbornene-2-carboxylic acid methyl ester (NB-COOCH 3) in relatively high activities (0.1-2.4 × 10 5 g polymer/mol Mt·h) and produced the addition-type copolymers with relatively high molecular weights (0.5 × 10 5-1.2 × 10 5 g/mol) as well as narrow molecular weight distributions (PDI < 2 for all polymers). Influences of the metals and comonomer feed content on the polymerization activity as well as on the incorporation rates (20.9-42.6%) were investigated. The achieved NB/NB-COOCH 3 copolymers were confirmed to be noncrystalline, exhibited good thermal stability (T d > 400°C) and showed good solubility in common organic solvents. Copyright © 2012 Wiley Periodicals, Inc.