Back‐bonding in Organonickel Complexes with Terpyridine Ligands – A Structural Approach

Abstract

Abstract A series of organonickel complexes [(R′terpy)Ni(aryl)]X (R′terpy = derivatives of 2,2′;6′,6″‐terpyridine; R′ = 4‐H, 4‐Cl, 4‐Tol and 4,4′,4″‐ t Bu 3 ; aryl = 2,6‐dimethylphenyl = Xyl or 2,4,6‐trimethylphenyl = Mes; X = Br or PF 6 ) have been prepared and characterized. The crystal structures exhibit a number of intermolecular H bond type interactions, but the structure determining force seems to be the packing of the aryl co‐ligands. The molecules reveal rather undistorted square planar coordination with a N 3 C ligand set, the central Ni–N bond being remarkably short, despite the expected strong trans influence of the aryl co‐ligands. The long‐wavelength absorptions were assigned to charge transfer transitions. No emission is observed at ambient temperature in the solid and in solution and at low temperature in glasses.