Ruthenium(II) complexes bearing thioether-azoimine tridentate SNN donor ligands: Synthesis, spectroscopic properties, structural characterization, electrochemistry, and catalytic activity

摘要

Ruthenium(II) solvato complexes with tridentate (SNN) thioether-azoimine ligands having the general formula trans-[Ru(L1)(Y)Cl-2] (1-2) [1.1 = 2 PhS(C6H4)N=NC-(COCH3)-NC6H5, Y= DMF (1); Y= acetonitrile (2)) and trans-[Ru(L2)(Y)Cl-2] (3-4) [L2 = 2-CH3S(C6H4)N=NC-(COCH3)-NC6H5, Y =DMF (3); Y= acetonitrile (4)) have been synthesized and characterized by various spectroscopic (IR, UV-Vis and 1 H NMR) techniques. The complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple around 1.35 V for Ru(III/II) and a reduction couple around -0.35 V for L(0/-). Catalytic activity of the compounds has been investigated for the hydrogenation of acetophenone. The relative catalytic activity was rationalized using calculated thermodynamics parameters of the partial dissociation of the complexes to give solvent (acetonitrile or DMF) and the rest of the complex. Geometry has been confirmed by single crystal X-ray study. The electronic structure, redox properties, electronic excitations and catalytic activity for the complexes are interpreted by density functional theory (DFT) calculations. (C) 2020 Elsevier B.V. All rights reserved.