Ruthenium, rhodium and iridium complexes containing pyrimidine based thienyl pyrazoles: Synthesis and antibacterial studies

Abstract

The reaction of pyrimidine based electron-rich heterocyclic thiophene pyrazoles and halide bridged arene d6 metal precursors yielded a series of mononuclear and dinuclear half sandwich d6 metal complexes. Mononuclear and dinuclear complexes formed by the ratio-based reaction between ligand and metal precursor. All these cationic complexes have been characterized by IR, UV–Vis, 1H NMR, 13C NMR spectroscopic techniques. Complex 5 has been established by single-crystal analysis. X-ray diffraction studies revealed the formation of mononuclear and dinuclear complexes and suggest that the vicinity around the metal atom is distorted octahedral. An in vitro study to screen the antibacterial potential of these complexes against pathogenic bacteria, S. aureus, K. pneumoniae, and E. coli was addressed. All the complexes display a better zone of inhibitions for both Gram-positive (S. aureus) and Gram-negative strains (K. pneumoniae, and E. coli). The minimum inhibitory concentrations (MICs) for the most active complex ranged from 0.125 to 0.25 mg/ml for S. aureus and Klebsiella Pneumoniae and 0.25–0.5 mg/ml for E. coli.