Synthesis and characterization of copper(I) and silver(I) complexes with heterocyclic bidentate ligands (N, X), X = S, Se

The synthesis and structural characterization of series of copper and silver homoleptic complexes [M(R-pyX)], M = Cu, Ag, X = S, Se; R = H, 3-CF3, 5-CF3 (not all combinations), is described. The copper compounds, as well as [Ag(pySe)] and [Ag(3-CF3-pySe)], were synthesised by electrochemical oxidation of anodic metal in a cell containing an acetonitrile solution of the corresponding proligand. The other homoleptic silver complexes were obtained by direct reaction between AgNO3 and the salt of the corresponding ligand in methanol. In addition, the reaction of the metal thiolate compounds with bis(diphenylphosphino)ethane (dppe) in acetone allowed the synthesis of heteroleptic compounds [M2(R-pyX)2(dppe)3]. The compounds obtained have been characterized by microanalysis, IR spectroscopy and mass spectrometry and, in cases where the complexes were sufficiently soluble, by 1H NMR spectroscopy. The proligands (3-CF3pySe)2 (1), (5-CF3-pySe)2 (2) and (5-CF3-pySe-DMF) (3) and the complexes [Cu(3-CF3-pyS)] (4), [Ag(3-CF3-pyS)] (5) and [Cu2(5-CF3-pyS)2(dppe)3] (6) were obtained as crystalline products and were studied by X-ray diffraction methods.