Research Information System
Journal of Molecular Structure, vol.1350, 2026 (SCI-Expanded, Scopus)
Two copper(II) complexes, triaquabis(4-sulfamoylbenzoato-κO1)copper(II) (Complex 1) and aquabis(methyl pyridine-3-carboxylate-κN)bis(4-sulfamoylbenzoato-κO1)copper(II) (Complex 2), were synthesized and characterized by SC-XRD, elemental analysis, FT-IR, and UV–Vis spectroscopy. Crystallographic studies showed that Complex 1 (C₁₄H₁₈CuN₂O₁₁S₂) crystallizes in the orthorhombic system (Cmc2₁, a = 22.66, b = 10.43, c = 8.40 Å), while Complex 2 (C₂₈H₂₈CuN₄O₁₃S₂) adopts a monoclinic system (C2/c, a = 24.79, b = 5.73, c = 23.81 Å, β = 110.7°). Both feature distorted square-pyramidal Cu(II) centers stabilized by hydrogen bonding, as confirmed by Hirshfeld surface analysis. FT-IR spectra showed characteristic metal–ligand vibrations (Cu–O ∼530 cm⁻¹ in both complexes, Cu–N ∼470 cm⁻¹ in Complex 2), while UV–Vis spectra exhibited d–d transitions around 750–765 nm, consistent with five-coordinate geometries. DFT calculations revealed that Complex 1 is more stable, with a larger HOMO–LUMO gap (5.36 vs. 4.39 eV) and more negative Gibbs free energy (–6195.6 vs. –2074.7 eV). Antibacterial activity was evaluated against B. cereus, B. subtilis, S. aureus, Escherichia coli, K. pneumoniae, and P. aeruginosa using the agar well diffusion method. In silico molecular docking studies further supported these results, demonstrating that Complex 2 exhibits stronger interactions with bacterial replication and transcription proteins, reflected in its lower binding energies. Collectively, the experimental and computational findings highlight structure–activity relationships and underscore the potential of these Cu(II) complexes as antibacterial agents.