Theoretical insights into the electronic structure of nickel(0)-diphosphine-carbon dioxide complexes

•The asymmetric stretching frequency of the bound carbon dioxide is an appropriate descriptor as electronic parameter for the spectator phosphine ligand.•The coordination strength of the carbon dioxide ligand is sensitive to the basicity of the diphosphine but insensitive to the chelate ring size.•The bond path between nickel and the coordinating oxygen only exists for strongly electron withdrawing phosphines.