Ruthenium Polypyridyl Complexes with Hydroxypyridine: Experimental, DFT Studies, and In Silico Antitubercular Activity Investigation

This study reports the synthesis, spectroscopic, molecular properties, and in silico biological assessment of ruthenium polypyridyl complexes with a hydroxypyridine ligand, [Ru(bpy)2(N boolean AND O)](PF6) (Ru-1) and [Ru(phen)2(N boolean AND O)](PF6) (Ru-2). The compounds have been characterized by FT-IR, UV, single crystal X-ray crystallography while molecular electronic properties have been considered within the framework of density functional theory (DFT) computation. The explicit interpretation of the vibrational spectra was assigned by the VEDA4e program. The results obtained from the natural bond analysis explicated that the highest stabilization energy E(2) for the Ru-2 molecule is 343.53 kcal/mol while the Ru-1 compound was observed to possess E(2) energy of 302.42 kcal/mol. The studied Ru-2 compound has been observed to exhibit high gastrointestinal absorption which might restrict the brain-blood barrier or any cytochrome p450 inhibition (1A2, 2C19, 3A4, and 3A4) without infringing any of the Lipniski rules. The molecular docking experiment reveal that the Ru-2 compound binds effectively with 2nv6 tuberculosis receptor with a corresponding binding affinity of - 8.6 kcal/mol obtained for Ru-1 molecule. However, when both compounds were docked with the 5syj receptor, the binding affinity was observed to be - 7.5 and - 6.7 kcal/mol for Ru-2 and Ru-1 respectively, which is comparably higher than the binding score observed for isoniazid standard drug. Ru-2 complex was observed to possess a high energy gap of 2.948 eV with a chemical softness of 0.678 eV, thus suggesting the studied molecule is highly stable and suitable and can be used as a potential anti-tubercular agent. The Uv-vis spectroscopy study divulged that all absorption spectra occurred at the visible region for both molecules respectively, which is in tandem with the obtained experimental lambda max.