Theoretical study of the strong intramolecular hydrogen bond and metal-ligand interactions in group 10 (Ni, Pd, Pt) bis(dimethylglyoximato) complexes

The structural and bonding characteristics of the bis(dimethylglyoximato) complexes of group 10 transition metals ([M(dmg)₂], where M = Ni, Pd and Pt) were investigated by means of quantum chemical computations. The equilibrium geometries, energetic and bonding properties were computed using the B3P86 exchange-correlation density functional in conjunction with a 6-311+(+)G^∗∗ basis set. The computations revealed that the strong O⁻?H-O hydrogen bond exists only in the presence of the metal cations. The free (dmg)₂²⁻ ligand has significantly different geometry in which the O⁻?H-O interaction is replaced by N?O-H bonds. The characteristics of the metal-ligand interactions were determined by natural bond orbital analysis.