Investigation of structural, spectral, electronic, and biological properties of 1,3-disubstituted benzimidazole derivatives

Abstract This article reports studies on benzimidazole based heterocyclic compounds (S3-S5). X-ray diffraction technique was applied to study the structure of (C23H19N4O2)+.Br−.H2O, namely 1-[(2-cyanophenyl)methyl]-3-[2-(4-nitrophenyl)ethyl]-1H-benzimidazol-3-ium bromide monohydrate (S3). The molecules are linked by C—H⋯Br hydrogen bonds in the crystal and there are π-π stacking interactions between the centroids of the benzene ring in the benzimidazole nucleus. The theoretical, and chemical data of S3-S5 were compared with experimental calculations via NMR, IR, and UV–Vis spectra of the molecules. Afterwards, the biological activities of the molecules were compared against colon cancer antigen proteins, ID 2HQ6, and a breast cancer protein, which is a crystal structure of a dimeric caspase-9, ID 2AR9. Experimental and theoretical studies have shown that the biological activity of the molecule S5 is higher than that of other molecules.