Structural studies and biological activity evaluation of Pd(II), Pt(II) and Ru(II) complexes containing N-phenyl, N`-(3-triazolyl)thiourea

Abstract

[MCl(H2L)(OH2)]·1.5H2O (M = Pd(II) (1) and Pt(II) (2)) and [Ru(H2L)2(OH2)2]·3H2O (3) (H3L: N-phenyl, N`-(3-triazolyl)thiourea) were synthesized, characterized and tested for their antibacterial activities against Staphylococcus aureus and Escherichia coli bacteria. The thiourea derivative is coordinated to Mn+ ions as a mono-negatively N,S-bidentate ligand via the enolization of C = S group and triazole N center. The density functional theory calculations reveal that presence of a water molecule in a trans position to triazole ring increased the stability of d8 metal ions complexes via the formation of strong Cl…NH intramolecular H-bond. The cis-Ru(II)-isomer with two isoenergetically H2L− molecules are more stable than the trans-analog. Coordination of H3L to Ru(II) ion did not alter the toxicity of the free ligand, while the interaction with the d8 metal ions gave rise to inactive compounds.