Terminal {Ni(II)-SH} complex promoted anaerobic catalytic sulfur atom transfer reaction: implication to the sulfide oxidase function of Cu/Zn-superoxide dismutase.

In mitochondria, the detoxification of molar excess HS as polysulfide proceeded an oxidation process promoted by Cu/Zn containing superoxide dismutase (SOD1) enzyme, which has been very recently reported as the alternative enzyme for cytosolic HS oxidation. Herein, we present Ni(II) complexes bearing the terminal SH group as a synthetic functional analogue for the sulfide oxidase function of SOD1. Synthesis, crystal structure and complete spectroscopic characterization of two sets of complexes, [NiL(PPh)] (2OMe/tBu) and tetraethyl salt of [NiL(SH)] (3OMe/tBu), were described (LOMe = ()-2-methoxy-6-(((2-sulfidophenyl)imino)methyl)phenolate and LtBu = ()-2,4-di--butyl-6-(((2-sulfidophenyl)imino)methyl)phenolate).

Non-covalent interactions in molecular architectures and solvent-free catalytic activity towards CO fixation of mononuclear Co(III) complexes installed on modified Schiff base ligands.

A set of mononuclear cobalt(III) octahedral complexes {[Co(L)(acac)] (Co-1H), [Co(L)(acac)] (Co-1Br), and [Co(L)(acac)] (Co-1NO2)} were synthesized using new-generation N/O donors, maleonitrile-tethered, tetradentate heteroscorpionate half-reduced Schiff base ligands, 2-(()-2-hydroxybenzylideneamino)-3-(pyridin-2-ylmethylamino)maleonitrile (H2LH), 2-(()-(5-bromo-2-hydroxybenzylidene)amino)-3-((pyridin-2-ylmethyl)amino)maleonitrile (H2LBr), and 2-(()-2-hydroxy-5-nitrobenzylideneamino)-3-(pyridin-2-ylmethylamino)maleonitrile (H2LNO2). All the compounds were well characterized spectroscopically and structurally. The non-covalent interactions present in the lattice of Co-complexes were studied in detail to explain the molecular architecture using the Hirshfeld surface (HS) analysis.