Synthesis, characterization and antimicrobial studies of mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones: Crystal structure of bis[{(μ2-diazinane-2-thione)(diazinane-2-thione)(triphenylphosphine)silver(I) nitrate}]

Mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones (imidazolidine-2-thione (Imt), diazinane-2-thione (Diaz) and 2-mercaptopyridine (Mpy)) having the general formulae [(Ph3P)Ag(thione)2]NO3 and [(Ph3P)2Ag(thione)]NO3 were prepared and characterized by elemental analysis, IR and NMR (1H, 13C and 31P) spectroscopic methods. The crystal structure of one of the complexes, [Ag(Ph3P)(Diaz)2]2(NO3)2 (1) was determined by X-ray crystallography. The title complex (1) is dinuclear, having each silver atom coordinated to three thione sulfur atoms of Diaz and to one phosphorus atom of PPh3 in a nearly tetrahedral environment, with an average P–Ag–S bond angle of 108.5°. The spectral data of the complexes are consistent with sulfur coordination of the thiones to silver(I). Antimicrobial activities of the complexes were evaluated by minimum inhibitory concentrations and the results showed that the complexes exhibit a wide range of activity against two gram-negative bacteria (E. coli, P. aeruginosa) and molds (A. niger, P. citrinum), while the activities were poor against yeasts (C. albicans, S. cerevisiae).

Mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones (imidazolidine-2-thione (Imt), diazinane-2-thione (Diaz) and 2-mercaptopyridine (Mpy)) having the general formulae [(Ph3P)Ag(thione)2]NO3 and [(Ph3P)2Ag(thione)]NO3 have been prepared and characterized by elemental analysis, IR and NMR (1H, 13C and 31P) spectroscopic methods. The crystal structure of one of the complexes has also been determined by X-ray crystallography. In the crystal structure of the title complex [Ag(Ph3P)(Diaz)2]2(NO3)2 (1), the central silver atom is coordinated to three thione sulfur atoms of Diaz and to one phosphorus atom of PPh3 in a nearly tetrahedral arrangement, with an average P–Ag–S bond angle of 108.5°. Antimicrobial activities of the complexes were evaluated by minimum inhibitory concentrations.Figure optionsDownload as PowerPoint slideHighlights
► The synthesis and spectral characterization of silver(I) complexes of triphenylphosphine and heterocyclic thiones is reported.
► The crystal structure of a novel dinuclear silver nitrate complex, [Ag(Ph3P)(Diaz)2]2(NO3)2 is presented.
► Antimicrobial activities of the complexes were investigated.