Structural elucidation, spectroscopic, and metallochromic studies of 2-(2-hydroxy phenyl)-1-H-benzimidazole complexes: Metal ions sensing, DNA binding, and antimicrobial activity evaluation

Three novel chelates, [Ru(L)(3)]2H(2)O, C1, [NiL(H2O)(3)(AcO)]H2O, C2, and [CuL(H2O)(AcO)], C3, derived from 2-(2-hydroxy phenyl)-1-H -benzimidazole) HL, have been designed. The structures of the isolated compounds have been elucidated by elemental analysis, molar conductance, thermal analysis, spectral data (UV-Vis, mass spectra, IR, fluorescence), thermal analysis (TGA) and magnetic moment measurements. The IR spectral data ascertained that the HL compound acts as a monobasic bidentate ligand via the O and N atoms of the OH and C=N groups of the benzimidazole moiety, respectively. The spectral and magnetic measurements implied octahedral structures for C1 and C2 and square planar geometry for C3. The kinetic and thermodynamic parameters of the thermal decomposition stages have been evaluated. Molecular orbital calculations have been performed. The metallochromic behavior of the investigated free ligand was studied in the presence of Ru(III), Ni(II) and Cu(II) ions. The observed spectral changes indicated the ability of HL to act as potential optical sensor for probing these metal ions. Interaction of the investigated compounds with CT-DNA was studied via electronic absorption and emission spectroscopy, as well as ethidium bromide displacement. The results suggested that all compounds interact through intercalative mode. The binding behavior and binding constants have been evaluated and discussed. The CT-DNA-binding constants confirmed the strong intercalation between the investigated ligand and metal complexes with the CT-DNA, suggesting that the investigated compounds can be used as promising therapeutic drug. Finally, the antimicrobial activities of the metal complexes have been screened. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Three novel chelates derived from HL have been designed, with detailed structural and spectral analyses showing their potential as optical sensors for metal ions. All compounds interact with CT-DNA through intercalative mode, with evaluated binding constants confirming strong intercalation between the investigated ligand and metal complexes with the CT-DNA, indicating their potential use as therapeutic drugs. The metal complexes also exhibited antimicrobial activities upon screening.