DFT modelling of cobalt and nickel complexes with dithiophosphinic acid

Calculations based on density functional methods are carried out for the dithiophosphinate cobalt and nickel complexes. An interpretation of the electronic structure of these complexes is made according Mulliken and Natural Population Analysis together with the Atoms in Molecules approach showing the kind of main interactions between metals and the ligand. Results show that the M-L bond is mainly governed by charge transfer from the ligand to the metal atom by the participation of the sulfur lone pair with similar covalent contribution for cobalt and nickel in case of octahedral complexes. In the case of tetrahedral cobalt complex they have a relative higher contribution with respect to the last. The calculated interaction energy confirms the preference for the formation of the tetrahedral cobalt complex if we take into account the low values of the frontier molecular orbital as it is shows by the molecular orbital analysis. The small difference in the interaction energy between tetrahedral and octahedral cobalt complexes gives possibilities for the formation of octahedral complexes.