Synthesis, structural characterization, antibacterial activity, DNA binding and computational studies of bis(2-methyl-1H-imidazole κN3)silver(I)dichromate(VI)

Abstract

A new silver complex [Ag(C4H6N2)2]2Cr2O7 (1) derived from Ag2[CrO4] and 2-methylimidazole has been synthesized and fully characterized by Single crystal X-ray diffraction, UV–Vis, FT-IR, elemental analysis, DFT and AIM calculations. The crystal structure of 1 shows that the discrete, ionic compound of [Ag(C4H6N2)2]2Cr2O7 consists of two [Ag(C4H6N2)2]+ cations bridged by a [Cr2O7]2− counter anion. In each of the [Ag(C4H6N2)2]+ complexes, the Ag center is coordinated by two N atoms from two distinct neutral monodentate 2-methylimidazole ligands in an almost linear geometry with AgN distances between 2.068(4) Å and 2.076(4) Å and NAgN bond angles of 179.4(2)° and 173.8(2)°. The NH⋯O and CH⋯ O hydrogen bonds, π⋯π stacking, CH⋯π and Ag⋯O interactions play an important role in the structural stabilization of the complex to generate a three-dimensional framework. The antibacterial activity and molecular docking studies of the free 2-methylimidazole ligand and the title complex show that these compounds have ability to inhibit the growth of the tested bacteria. A scanning probe microscopy (SPM) study of the treated bacteria was carried out to investigate the structural changes caused by the interactions between the complex and target bacteria. The interaction of the complex 1 with the E.coli DNA (E-DNA) has been studied by UV–Vis absorption, competitive DNA-binding studies with ethidium bromide by fluorescence and gel electrophoresis techniques. These experiments indicate that the complex interacts with DNA by intercalative binding.