TETRAIMINE DIRUTHENIUM COMPLEX: SYNTHESIS, CHARACTERIZATION, ANTIMICROBIAL ACTIVITY AND SARS-COV-2 MOLECULAR DOCKING STUDIES

The synthesis, spectroscopic, and biological activity of a new dinuclear ruthenium complex containing a biphenyl spacer and four imine functionalities are reported. 4,4' Tetrakis(methaneylylidene)tetraphenol ligand was obtained via a condensation reaction of 4-hydroxybenzaldehyde and 3,3’-diaminobenzidine. The coordination of the tetraimine N,N donor Schiff base ligands with cis-dichlorobis(2,2’ bipyridine) ruthenium resulted in the formation of a novel tetraimine diruthenium complex. The ligand and the diruthenium complex were characterized using various analytical techniques, including 1H NMR, FT-IR spectroscopy, and mass spectrometry. The antimicrobial activity of the free tetraimine ligand and its diruthenium complex was evaluated against Candida albicans, Escherichia coli, Staphylococcus aureus, Proteus vulgaris, and Streptococcus pyogenes, and was compared with that of its monometallic congener. Zone of inhibition measurements demonstrated notable antimicrobial properties, indicating its potential for further therapeutic application. In addition, molecular docking studies were conducted to investigate interactions between the tetraimine ruthenium complex and SARS-CoV-2 nonstructural protein receptors. The most favorable binding conformation showed significant hydrophobic interactions and an affinity energy of –18.35 kcal/mol, suggesting strong interactions between the complex and key residues of the viral proteins. Among all tested compounds, the dinuclear complex gave the highest antimicrobial activity. These findings show the potential of the tetraimine diruthenium complex as a promising antimicrobial agent and inhibitor of SARS-CoV-2, a highly transmissible human pathogen.