Nickel complexes bearing N,N,N-tridentate quinolinyl anilido-imine ligands: Synthesis, characterization and catalysis on norbornene addition polymerization

The N,N,N-tridentate quinolinyl anilido-imine ligands 2-(ArNC(H))C6H4-HNC9H6N (LaH, Ar = 2,6-Me2C6H3; LbH, Ar = 2,6-(Pr2C6H3)-Pr-i) and 2-(C9H6N)NC(H)C6H4-HNAr (LcH, Ar = 2,6-Me2C6H3; LdH, Ar = 2,6-(Pr2C6H3)-Pr-i) were synthesized and characterized. Reactions of these ligands with (BuLi)-Bu-n and subsequent additions of NiCl2(DME) afford the N,N,N-tridentate nickel complexes [2-(ArNC(H))C6H4-NC9H6N] NiCl (Ar = 2,6-Me2C6H3 (1a), 2,6-(Pr2C6H3)-Pr-i (1b)) and [2-(C9H6N)NC(H)C6H4-NAr]NiCl (Ar = 2,6-Me2C6H3 (2a), 2,6-(Pr2C6H3)-Pr-i (2b)). All the complexes were fully characterized by NMR and elemental analyses. X-ray diffraction analyses of 1b and 2b revealed an almost square-planar geometry around the metal center. When activated with MAO, these nickel complexes can be used as catalysts for the vinyl addition polymerization of norbornene affording high molecular weight polymer. (C) 2013 Elsevier B. V. All rights reserved.