Variable structural bonding modes and antibacterial studies of thiosemicarbazone ligands of ruthenium, rhodium, and iridium metal complexes

Abstract

Arene metal precursors on treatment with thiosemicarbazone ligands (L1, L2, and L3) yielded a series of cationic mono- and binuclear complexes (1–9) with N∩S bonding mode. In general, the complexes have been formulated as [(p-cymene)Ru(L)Cl]⁺ and [Cp*₂M₂(L)₂]⁴⁺ where L = L1, L2, L3, M = Rh/Ir. Contrary to previous results [1], ruthenium complexes portrayed mononuclear bidentate chelation while rhodium and iridium complexes revealed dinuclear bridging coordination through sulfur and imine nitrogen atoms. All these complexes have been characterized by various spectroscopic techniques and antibacterial studies have been carried out for the complexes as well as the ligands, where 5 and 8 showed good inhibitory antibacterial activity.

Graphical Abstract

Keywords:

• Ruthenium
• rhodium
• iridium
• thiosemicarbazone
• antibacterial

Acknowledgements

Lathewdeipor Shadap thanks Dr. Werner Kaminsky of the Department of Chemistry, University of Washington for his help with the crystal data and CSIR, New Delhi, India for financial assistance in the form of JRF, DST-PURSE SCXRDand NEHU-SAIF, Shillong, India for providing Single Crystal X-ray analysis and other spectral studies.

Disclosure statement

No potential conflict of interest was reported by the authors.