Syntheses, crystal structure and theoretical investigation of novel heteroleptic complexes of nickel(II) with N-R-sulfonyldithiocarbimate and phosphine ligands

Five new complexes of general formula: [Ni(RSO2NCS2)(dppe)], where R = C6H5 (1), 4-ClC6H4 (2), 4-BrC6H4 (3), 4-IC6H4 (4) and dppe = 1,2-bis(diphenylphosphino)ethane and [Ni(4-IC6H4SO2NCS2)(PPh3)2] (5), where PPh3 = triphenylphosphine, were obtained in crystalline form by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate K2(RSO2NCS2) and dppe or PPh3 with nickel(II) chloride in ethanol/water. The elemental analyses and the IR, 1H NMR, 13C NMR and 31P NMR spectra are consistent with the formation of the square planar nickel(II) complexes with mixed ligands. All complexes were also characterized by X-ray diffraction techniques and present a distorted cis-NiS2P2 square-planar configuration around the Ni atom. Quantum chemical calculations reproduced the crystallographic structures and are in accord with the spectroscopic data. Rare C–H···Ni intramolecular short contact interactions were observed in the complexes 1–5.