Heterocyclic thioamide derivatives of coinage metals (Cu, Ag): Synthesis, structures and spectroscopy

Heterocyclic thioamides, namely, imidazolidine-2-thione (imdzSH), 1-methyl-1, 3-imidazoline-2-thione (mimzSH), thiazolidine-2-thione (tzdSH) and 2,4-dithiouracil (dtucH2) with silver(I)/copper(I) salts in presence of triphenyl phosphine (PPh3) have yielded complexes of different nuclearity: mononuclear, [Ag(η1-S-HL)(PPh3)2Cl] (HL = imdzSH 1, mimzSH 2, tzdSH 3), dinuclear, [Ag2(η1-S-tzdSH)2(μ-S-tzdSH)2(PPh3)2](NO3)2 4, and polynuclear, {Cu(μ-S,S-dtucH2)(PPh3)2X} (X = Cl 5, Br 6, I 7). All complexes have been characterized using analytical data, IR and multinuclear NMR spectroscopy (1H, 13C and 31P) and single crystal X-ray crystallography. The thio-ligands are bonded to the metal centers as neutral sulfur donors. The geometry around each metal center is distorted tetrahedral. Complexes 5–7 represent first examples of polymers of 2,4-dithiouracil in its coordination chemistry with metal salts. The hydrogen bonding interactions lead to the formation of 1D (2, 3, 7) and 2D (1, 4–6) sheet structures.