Synthesis, X-ray structures and antibacterial activities of silver(I) complexes of 1,3-bis(diphenylphosphano)propane (Dppp) and N,N′-dimethylthiourea (Dmtu)

Abstract

Three silver(I) complexes, [Ag(Dppp)2]NO3·0.5H2O (1), [Ag2(Dppp)2(Dmtu)4](NO3)2 (2) and [Ag(PPh3)2(Dmtu)2]NO3·0.5H2O (3) (where Dppp = 1,3-bis(diphenylphosphano)propane, PPh3 = triphenylphosphane and Dmtu = N,N′-dimethylthiourea), were prepared and characterized by IR and NMR (1H, 13C and 31P) spectroscopic methods. The crystal structures of the complexes were determined by X-ray crystallography. All three complexes are ionic, containing nitrate as a counter ion. In complex 1, two Dppp ligands are coordinated to an Ag(I) ion, each acting as a chelating donor to form a six membered ring. Complex 2 is dinuclear with the individual silver(I) ions bound to two phosphorus atoms of two different Dppp ligands and two sulfur atoms of N,N′-dimethylthiourea. The geometry around the Ag(I) atoms in both complexes is distorted tetrahedral. Complex 3 is mononuclear having the silver(I) ion coordinated by two PPh3 and two Dmtu ligands in a nearly tetrahedral environment. The Dmtu ligands in complexes 2 and 3 are coordinated in a terminal mode. The complexes were evaluated for their antibacterial activity and they were found to exhibit moderate activity against most of the bacteria.