Synthesis and spectroscopic characterization of antibacterial rhodium and ruthenium organometallics molded by C–H activation at the ortho position of a phenyl ring

Abstract

Drug resistance in pathogens is a growing global health problem. The development of new drugs is a risky, time-consuming, and expensive process, since only a few got final approval. Organometallic compounds attracted attention due to their promising anticancer activities. In this study, four cyclometallates containing ruthenium and rhodium ions were synthesized from two phenolic azo ligands. These molecules were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility, FT-IR, mass, electronic, ¹H, ¹³C{¹H}, and ³¹P{¹H} NMR spectral studies. The general formula for the complexes is trans-[M(PPh₃)₂(Cl)(L)], where M = Rh or Ru, PPh₃ = triphenylphosphine, and L = phenolic azo ligand. All the complexes possess prominent antibacterial activity against Escherichia coli and Mycobacterium tuberculosis as compared to market drugs. The interactions of rhodium derivatives with plasma–protein were also studied.

Cyclometalation of a pendant aromatic ring is an example of C–H bond activation. Organometallic compounds were biologically potent and may be helpful for pharmaceutical industries for biological targets.

Keywords:

• Antibacterial
• C–H activation
• Organometallics
• Rhodium
• Ruthenium

Acknowledgements

Authors are grateful to acknowledge Head, Department of Chemistry, Govt. Science College, Jabalpur for providing laboratory facilities. Thanks are also due to SAIF, CDRI, Lucknow and SAIF, Pondicherry University, Pondicherry for recording spectra and elemental data. RM is thankful to Dr J.J. Ahire, Postdoc Fellow, University of Stellenbosch, South Africa, for his kind help in statistical analysis.