Five‐coordinate dinuclar cobalt (II), copper (II), zinc (II) and cadmium (II) complexes with 4‐bromo‐N‐(2‐pyridinylmethylene)benzenamine: Synthesis,characterisation and methyl methacrylate polymerization

A series of late transition metal complexes, (bpma)Co(μ – Cl)Cl] ₂ , (bpma)Cu(μ – Cl)Cl] ₂ , (bpma)Zn(μ – Cl)Cl] ₂ and (bpma)Cd(μ – Br)Br] ₂ (where bpma is 4‐bromo‐N‐((pyridin‐2‐yl)methylene)benzenamine) have been synthesized and structurally characterized. The X‐ray structures of dimeric complexes (bpma)M(μ – X)X] ₂ (M = Co, Cu and Zn, X = Cl; M = Cd, X = Br) showed a distorted 5‐coordinate trigonal bipyramidal geometry involving two nitrogen atoms of N,N‐bidentate ligand, two bridged and one terminal halogen atoms. The complex (bpma)Cu(μ – Cl)Cl] ₂ revealed the highest catalytic activity for the polymerisation of methyl methacrylate in the presence of modified methylaluminoxane with an activity of 9.14 × 10⁴ g PMMA/mol·Cu·h at 60 °C and afforded syndiotactic poly (methylmethacrylate) (rr = 0.69).