Synthesis, structural elucidation, single crystal, and theoretical studies of copper triazole complex

A new copper(II) complex, [CuCl₂(ATS)(bpy)] (ATS = (E)− 2-(((4H-1,2,4-triazol-4-yl)imino)methyl)phenol; bpy = 2,2′-bipyridine), was synthesized and characterized by elemental (CHN), UV–Visible, and FT-IR spectroscopy, along with single-crystal X-ray diffraction (SC-XRD) analyses. In the crystal structure of the complex, the metal center is coordinated by an ATS, a 2,2′-bipyridine, and two chloride ions, forming a coordination geometry that lies between trigonal bipyramidal and square pyramidal. This coordination is further validated by DFT calculations, which also provide insights into frontier orbital energies, revealing the electronic features that govern the redox behavior. Intermolecular interactions are studied using Hirshfeld surface analysis to highlight their role in the stability of crystal packing. The cyclic voltammetric studies of the complex showed a distinct Cu(II)/Cu(I) redox response, indicating active electron transfer properties associated with the coordinated triazole imine ligand framework. Scan rate studies revealed that the electrode process is predominantly diffusion-controlled, suggesting that mass transport governs the redox behavior in solution. Electronic properties of the synthesized triazole ligand (ATS) and copper(II) complex were investigated by band gap analysis using UV–Visible analysis, which revealed a wider band gap for the copper complex as compared to the ligand. In silico molecular docking revealed that the Cu(II) complex exhibits strong binding affinity for DNA.