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

•Synthesis and characterization of four N,N,N-tridentate nickel complexes.•N,N,N-Tridentate nickel complexes catalyzed addition polymerization of norbornene.•Different ligands show different effects on catalysis.

The N,N,N-tridentate quinolinyl anilido–imine ligands 2-(ArNC(H))C6H4–HNC9H6N (LaH, Ar = 2,6-Me2C6H3; LbH, Ar = 2,6-iPr2C6H3) and 2-(C9H6N)NC(H)C6H4–HNAr (LcH, Ar = 2,6-Me2C6H3; LdH, Ar = 2,6-iPr2C6H3) were synthesized and characterized. Reactions of these ligands with nBuLi 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-iPr2C6H3 (1b)) and [2-(C9H6N)NC(H)C6H4–NAr]NiCl (Ar = 2,6-Me2C6H3 (2a), 2,6-iPr2C6H3 (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.

Graphical abstractSeveral Nickel complexes supported by quinolinyl decorated anilido–imine ligands were synthesized and used as catalysts for norbornene addition polymerization.Figure optionsDownload full-size imageDownload as PowerPoint slide