A series of isomorphic cobalt(II), nickel(II) and zinc(II) complexes of mixed dithiophosphonate, 2,2-bipyridine and 1,10-phenanthroline ligands: Synthesis, structure, and theoretical calculations

Abstract

Transition-metal complexes of dithiophosphonate ligands have attracted recent interest due to their involvement in several established and newly emerging applications. Herein, we report on the synthesis of six new complexes of Co(II), Ni(II), and Zn(II) and mixed dichalcogen (dithiophosphonate) and dipnictogen (2,2-bipyridine, and 1,10-phenanthroline) ligands: [Co{(S2P(4-C6H4OMe)(OCH(CH2CH3)2}2(C10H8N2)] 1, [Co{(S2P(4-C6H4OMe)(OCH2CH2CH2CH3)}2(C10H8N2)] 2, [Ni{S2P(4-C6H4OMe)(OCH3)}2(C12H8N2)] 3, [Ni{(S2P(4-C6H4OMe)(OCH(CH2CH3)2)}2(C12H8N2)] 4, [Zn{(S2P(4-C6H4OMe)(OCH3)}2 (C12H8N2)] 5 and [Zn{(S2P(4-C6H4OMe)(OCH2CH3)}2(C12H8N2)] 6. The complexes were characterized by solution 1H and 31P NMR spectroscopy, electrospray ionization mass spectrometry, elemental analysis, and FTIR. The crystal structures of 1, 3, 5, and 6 were established by single-crystal X-ray diffraction analysis. The four complexes are isomorphic and crystallize in the triclinic system, space group P-1, with Z = 2. Density functional theory (DFT) calculations of the electronic and structural properties of the complexes were carried out to estimate different quantum chemical properties. Crystallographic analysis showed that the Co(II) and Ni(II) metal centers in 1 and 3, respectively, adopted a distorted octahedral geometry, coordinating through the S (dithiophosphonate) and N (dipnictogen) donor atoms, while the Zn(II) center in 5 and 6 both adopted tetrahedral geometries. The obtained computational-based chemical parameters proved to be significant in evaluating the plausible reactivity and stability patterns of these complexes.