Structural characterization of novel 1H-1,2,3-triazole copper(II) complex: insight from experiment and quantum chemistry

Currently, 3d metal complexes are of great importance in modern research and industrial processes of organic synthesis, allowing for the efficient and sustainable synthesis of organometallic compounds. Most metals with acceptor properties have become a pressing issue. Also, copper (Cu) stands out as a promising method due to its low cost, relatively low toxicity, and rich redox properties [1]. Copper ions are widely used in catalysis and coordination chemistry because they exhibit different oxidation states, have flexible coordination geometries, and form stable complexes with donor atoms of ligands [2]. In recent years, the synthesis of new derivatives of 1,2,3-triazole derivatives has been rapidly developing due to their pharmacological and biological activity; because of this, ligands containing a 1,2,3-triazole fragment, one of the 5-membered heterocyclic compounds, have attracted particular interest in the synthesis of Cu-based complexes due to their strong N-donor properties [3]. In this study, we synthesized the Cu-based compound C₃₄H₂₆Br₄Cl₂CuN₆O₆ (1) with (1-(2-bromophenyl)-1H-1,2,3-triazol-4-yl)methyl 2-(4-bromophenoxy)acetate and characterized it by single-crystal X-ray diffraction, and performed conformational calculations based on quantum chemical analyses. For this complex compound, supramolecular and Hirshfeld surface analysis were performed to determine the intermolecular interactions. According to our results, intermolecular and intramolecular hydrogen bonds: C—H···O and C—H···N and C—Br···π stacking interactions are associated. Three-dimensional Hirshfeld surface analysis and two-dimensional fingerprint plots showed that the structures are dominated by H···H, H···C/C···H and H···O/O···H contacts; these interactions present in the determined molecular structure were characterized as stabilizing factors in the unit cell. Quantum chemical analysis revealed that the N atom located at the 3^rd position in the triazole ring of the ligands has electron-rich donor properties in this complex.

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2. Hakimov et al. Acta Cryst. 2025. E81, 271–274.
3. Hakimov et al. Acta Cryst. 2024. E80, 910–912.