Electrochemical synthesis and structural characterization of copper and silver complexes of imidazolidine-2-thione ligands

The electrochemical oxidation of anodic metal (copper and silver) in acetonitrile solutions of the appropriate 1-R-imidazolidine-2-thione (1-RImSH) afforded complexes of composition [M(1-RImS)], M = Cu, Ag, R = Me, Et, Pr, iPr. The compounds have been characterized by microanalysis, IR, NMR and mass spectroscopy and, in the case of [Cu(1-EtImS)] (1), [Cu(1-PrImS)] (2), [Ag(1-PrImS)] (3) and [Ag(1-iPrImS)] (4), by X-ray diffraction. Compounds (1) and (2) are tetranuclear with an array of four copper atoms at the vertices of a tetrahedron bridged by four sulfur atoms. Each copper atom has a distorted trigonal [CuS2N] environment with each ligand acting as a μ2-N,S(η2-S; η1-N) bidentate S-bridging ligand. Complexes 3 and 4 are hexanuclear with six silver atoms at the vertices of a distorted octahedron and the ligand acting as a μ2-N,S(η2-S; η1-N) bidentate S-bridging five-electron donor. In the crystals the copper molecules are interconnected by weak intermolecular C–H⋯S and C–H⋯π interactions but, in contrast, the silver molecules are linked by weak intermolecular C–H⋯N and C–H⋯π interactions.

New multinuclear copper (I) and silver (I) 1-R-imidazolidine-2-thionates of the general formula [Cu(1-RImS)] and [Ag(1-RImS)] (where R = Me, Et, Pr, iPr) have been synthesized and characterized. The crystal structures of [Cu(1-EtImS)] (1), [Cu(1-PrImS)] (2), [Ag(1-PrImS)] (3) and [Ag(1-iPrImS)] (4) were determined by X-ray diffraction. Compounds (1) and (2) are tetranuclear and the complexes (3) and (4) are hexanuclear. In all these compounds each metal atom has a distorted trigonal [MS2N] environment with each ligand acting as a μ2-N,S(η2-S; η1-N) bidentate S-bridging ligand.Figure optionsDownload as PowerPoint slide