Synthesis, structure characterization, spectral properties, DFT calculations, hirshfeld surface analysis, thermal stability and bioactivity of a new sulfamethoxazole zinc(II) complex

Abstract

This study reports the synthesis of a new sulfamethoxazole zinc(II) coordination complex: bis(5-methyl- 3-isoxazol-2-yl sulfanilamido)-diaqua-zinc(II), C20H24N6O8S2Zn, (I). Synthesized compound has been fully characterized by single-crystal and powder X-ray diffraction, FT-IR, UV–visible absorption and NMR (1H and 13C) spectroscopy techniques. In Zn(II) coordination sphere, sulfamethoxazole behaved as monodentate ligand and coordinated via nitrogen of sulfonamide group. Complex (I) was recovered in its crystalline form and was analyzed by single-crystal X-ray diffraction technique which held orthorhombic crystal system with space group (Pnma). The molecules of (I) are linked into chains through intermolecular N–H···O, O–H···O and C–H···π non covalent interactions. The intermolecular contacts were examined using Hirshfeld Surface investigation. Furthermore, computational analysis were performed through Density Functional Theory (DFT) utilizing the mPW1PW91 basis set at the TZVP level of theory and the theoretical results were correlated with experimental data. The antimicrobial and antifungal activities of the free ligand and its synthesized Zn(II) coordination complex were evaluated using the well-diffusion method in DMSO. The microbial strains investigated include one Gram-positive, five Gram-negative and three funguses bacterial strains using the standard antibiotics “Cotrimoxazole” as positive control.