Osmium-hydride-carbonyl complex with thioether containing Schiff base ligand: Synthesis, crystal structure, electrochemistry and catalytic transfer hydrogenation

Abstract

A new osmium(II) carbonyl complex, [Os(H)(CO)(PPh3)2(L)] (1) with thioether containg NNS donor ligand (where L = 2-(ethylthio)-N-((pyridine-2-yl)methylene))benzenamine) is synthesized and characterized by various spectroscopic techniques. The distorted octahedral environment around osmium in the complex is confirmed by single crystal X-ray structure. Cyclic voltammogram in acetonitrile exhibits Os(II)/Os(III) oxidation and ligand based reduction. The complex effectively catalyzed the transfer hydrogenation reaction of ketones in high yields in i-PrOH. The electronic structure and redox properties are interpreted by DFT studies.