Aminobenzimidazole‐based (η6‐p‐cymene)ruthenium (II) complexes as nascent anticancer chemotherapeutics: Synthesis, crystal structure, DFT studies, HSA interactions, molecular docking, and cytotoxicity

Abstract

Two half‐sandwich organometallic ruthenium (II) complexes containing analogs of aminobenzimidazole of molecular formula [η6‐p‐cymene)Ru (LH)Cl2]1and [η6‐p‐cymene)Ru (LMe)Cl2]2, whereLHandLMerepresent 2‐aminobenzimidazole and 2‐amino‐1‐methylbenzimidazole, respectively, have been synthesized and characterized by FT‐IR, NMR (1H,13C), ESI‐MS, elemental analysis, and single X‐ray crystallography (for1). Both complexes1and2were studied for human serum albumin (HSA) binding affinity using intrinsic, synchronous, three‐dimensional (3D) fluorescence, thermodynamics parameter, and Förster resonance energy transfer (FRET) analysis. The Stern–Volmer constant (KSV) values are of the order of ×105 M−1and increases inKSVwith temperature ascertained the static quenching. The molecular docking of both the complexes with HSA was carried out to ascertain the binding sites/pockets. Furthermore, compounds were evaluated for their cytotoxic potential against three human cancer cell lines, namely, HeLa, HepG2, MCF‐7, and non‐tumorigenic HEK293 cells. The IC50value of2was found to <10 μM against Hela and HepG2 cancer cells and has better cytotoxic properties than cisplatin (a standard drug), yet showed minimal toxicity against HEK293 cells. These results suggest further investigation for the development of ruthenium complex2as potential anticancer therapeutics.