Synthesis, Crystal Structure and DNA-Binding Study of a New Copper(II) Complex Containing Mixed-Ligand of Iminodiacetate Dianion and 6-Nitro-1H-benzimidazole

Abstract  A mixed-ligand complex Cu(IDA)(NBZIM)(H₂O) (IDA = iminodiacetate dianion, NBZIM = 6-nitro-1H-benzimidazole) has been synthesized and characterized by elementary analysis, IR, UV-Vis, molar conductivity and single crystal X-ray diffraction. It crystallizes in the triclinic system, space group P with a = 6.9423(14), b = 9.3100(19), c = 11.754(2) ?, α = 69.61(3), β = 85.87(3), γ = 83.87(3)°, Z = 2, R ₁ = 0.0463 and ωR ₂ = 0.0987. The single crystal X-ray analysis reveals that the Cu(II) atom is coordinated by one tridentate iminodiacetate dianion, one monodentate nitrobenzimidazole molecule and one water molecule, in a distorted square base pyramidal coordination geometry. The iminodiacetate dianion chelates the Cu(II) atom in the meridional mode. A three-dimensional network is formed by hydrogen bonds and stabilized by NBZIM π-π stacking interactions. The interaction of the complex with Fish sperm DNA has also been studied using absorption spectra. Index Abstract  In the crystal of Cu(IDA)(NBZIM)(H₂O), each molecule is linked to other six neighbouring ones by ‘eight’ hydrogen bonds in four cases by means of the ‘symmetry related’ linkage.