The first nickel(II) complexes of disubstituted diphenyldithiophosphates: Synthesis, spectroscopic, electrochemical, antifungal and single crystal X-ray analysis

Abstract

Five novel nickel(II) complexes of disubstituted diphenyldithiophosphates, [{(ArO)2PS2}2Ni] [Ar=2,4-(CH3)2C6H3 (1), 2,5-(CH3)2C6H3 (2), 3,4-(CH3)2C6H3 (3), 3,5-(CH3)2C6H3 (4) and 4-Cl-3-CH3C6H3 (5)], have been synthesized in aqueous medium and structurally characterized by IR, heteronuclear NMR (1H, 13C and 31P) spectroscopic and single crystal X-ray analyses. Complexes 1 and 5 crystallize in the triclinic space group P1¯, whereas complex 4 crystallizes in the monoclinic space group P21/n. In these complexes, the ligands are coordinated to the nickel ion as a bidentate chelating agent via the two thiolate sulfur atoms, leading to a spirocyclic system. Crystal structure determination of complexes 1, 4 and 5 reveals that the complexes consist of mononuclear units with the nickel(II) ion coordinated in a bis-bidentate fashion with a distorted square planar coordination environment. A cyclic voltammetry experiment was used to probe the redox capabilities of complex 4. The investigated complexes, along with the ligands, have been screened for in vitro antifungal activities against the fungus Penicillium chrysogenum.