Visible light induced generation of nitric oxide from designed ruthenium nitrosyl complex and studies on antibacterial activity

Abstract

In this article, a chloro-bridged dinuclear ruthenium complex Ru-(a) has been synthesized, which was employed for the synthesis of a photolabile NO liberating complex Ru-(b). A newly synthesized tridentate ligand 2-methyl-6-((2-phenyl-2-(pyridin-2-yl)hydrazineylidene)methyl)pyridine with three N-atoms as donating site was used to synthesize the complex Ru-(a). The molecular structure of Ru-(a) was investigated by single-crystal X-ray crystallography and, in solution was characterized by or ESI mass spectrometry. Several spectroscopic techniques were used for the characterization of the ligand as well as complexes. To understand the electronic structure of Ru-(a) and Ru-(b), DFT computations were utilized. By the utilization of visible light, photo-liberation experiments were examined. The amount of NO released during the photodissociation experiment was measured using the Griess reagent assay technique. The photodissociated NO was fruitfully transported to reduced myoglobin (Mb). The antibacterial activity against Escherichia coli was carried out with 31.2 μg/mL concentration of Ru-(b). In the final results, we detected considerable antibacterial activity against E. coli and showed >99 % inhibition of the bacterial cells after 120 min of the experiment on exposure to visible light. These investigations proposed that Ru-(b) could be employed to treat several topical deliveries of NO for treating various topical and bacterial infections.