Ni-thiosaccharinate complexes: Synthesis, characterization and DFT studies. Biological properties as superoxide dismutase mimetics and as anti-carcinogenic agents

Abstract

This report describes the synthesis and characterization of two nickel thiosaccharinate complexes, [Ni(tsac)2(PPh3)2] (1) and [Ni(tsac)2(dppe)]·CH3CN (2), where tsac = thiosaccharinate anion, PPh3 = triphenylphosphane and dppe = bis(diphenylphosphanyl)ethane. Elemental analysis, FTIR, 1H, 13C and 31P NMR spectra and single crystal X ray diffraction studies of the complexes are presented. DFT optimizations of the two new compounds were performed in order to verify the FTIR vibrational assignations. The two nickel(II) thiosaccharinate complexes consist of mononuclear units in which the Ni atoms are the centre of square-planar coordination spheres, surrounded by two sulfur thiosaccharinate atoms and two phosphorous atoms from the phosphane ligands. In both complexes, the anions are mono-coordinated to the metal. In the [Ni(tsac)2(PPh3)2] structure, the phosphane moieties are located in trans position. In the [Ni(tsac)2(dppe)] structure, the dppe ligand chelates to the metal centre, as expected. Additionally, the superoxide dismutase (SOD) mimetic activity of the complexes was measured and it is reported herein. The effects of the complexes on cell proliferation were also studied and are described.