Synthesis, structure characterization, Hirshfeld surface analysis, thermal and antibacterial properties of 2-nitrobenzylpyridinium tetrachlorocuprate(II)

Abstract In this paper, by utilizing the 2-nitrobenzylpyridinium salt and copper(II) chloride, 2-nitrobenzylpyridinium tetrachlorocuprate(II) [2-NO₂BzPy]₂[CuCl₄](1) was obtained. The single-crystal X-ray diffraction of the complex [2-NO₂BzPy]₂[CuCl₄](1) analysis indicates that the molecular structure of [2-NO₂BzPy]₂[CuCl₄](1) in the unit cell contains two [2-NO₂BzPy]⁺ cations and one [CuCl₄]²– anion crystallizes in the monoclinic space group P2₁/c. The bulk phase purity, homogeneity, and morphology of [2-NO₂BzPy]₂[CuCl₄](1) were checked using powder XRD. The C − H···Cl, C − H···O, and C − H···N weak hydrogen bonds were found in the crystal, which play an important role in the stacking and stabilization. According to Hirshfeld surface analysis of the crystal structure, the mostly significant contributions to the crystal packing are from H···Cl/Cl···H (35.7%), H···H (24.0%), and H···O/O···H (17.8%) contacts. FT-IR, UV-Vis spectrum, and TG-DTA measurements of 1 were investigated. The low energy gap was calculated by the UV-Vis spectrum to be 1.72 eV. Simultaneously, antibacterial studies were conducted on [2-NO₂BzPy]Cl and [2-NO₂BzPy]₂[CuCl₄], which found that 1 had better antibacterial activity against E. coli and S. aureus.