Synthesis, characterization and antimicrobial studies of mixed ligand silver(I) complexes of thioureas and triphenylphosphine; crystal structure of {[Ag(PPh3)(thiourea)(NO3)](2)center dot[Ag(PPh3)(thiourea)](2)(NO3)(2)}

摘要

Mixed ligand silver(I) complexes of triphenylphosphine and thioureas (thiourea (Tu), N-methylthiourea (Metu), N,N'-dimethylthiourea (Dmtu) and N,N'-diethylthiourea (Detu)) with the general formulae, [(Ph3P)(2)Ag(thione)]NO3 and [(Ph3P)Ag(thione)(2)]NO3, have been prepared and characterized by elemental analysis, IR and NMR H-1, C-13 and P-31) spectroscopic methods. The crystal structure of one of them has been determined by X-ray crystallography. The spectral data of the complexes are consistent with sulfur coordination of the thiones to silver(I). The single crystal X-ray structure of complex 1, {[Ag(PPh3)(thiourea)(NO3)]2 center dot[Ag(PPh3)(thiourea)](2)(NO3)(2)}, shows that the complex consists of two independent centro-symmetric binuclear units, each having the silver atoms coordinated to one PPh3 and two bridging thiourea molecules. In one of the independent units the silver atom is additionally bound to a nitrate ion, leading to a tetrahedral geometry, while in the other unit the silver atom adopts a trigonal planar environment. Antimicrobial activities of the complexes were evaluated by their minimum inhibitory concentration and the results showed that the complexes show a wide range of activity against two gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and molds (Aspergillus niger, Penicillium citrinum), while the activities were poor against yeasts (Candida albicans, Saccharomyces cerevisiae). However, the title complex did not show activity against any tested microorganism.