Synthesis, Characterization, DFT Calculations, and Biological Studies of Novel N-(5-methylisoxazol-3-yl)-4-(((1E, 2E)-3-phenylallylidene)amino) benzenesulfonamide Schiff base (SMZ-CAL) and its Cu(II) and Ni(II) Metal Complexes

This manuscript presents a comprehensive study on the synthesis and characterization of two novel Cu(II) and Ni(II) complexes incorporating N-(5-methylisoxazol-3-yl)-4-(((1E,2E)-3-phenylallylidene) amino) benzenesulfonamide (SMZ-CAL). The investigation focuses on the structural analysis of these complexes using elemental analyses, IR, UV-vis, 1HNMR, 13C NMR, as well as HOMO-LUMO analysis and determination of the band gap through DFT/6-311G++(d,p) calculations. The biological activity of SMZ-CAL and its metal complexes, [Cu(SMZ-CAL)2] and [Ni(SMZ-CAL)2], against Gram-positive and Gram-negative bacteria was evaluated. Inhibition zone diameters were measured at different concentrations, indicating the compounds' effectiveness in inhibiting bacterial growth. The complexes exhibited promising biological activity, particularly against Gram-negative bacteria, suggesting their potential as effective antibiotics. This study investigated the antioxidant activity of SMZ-CAL, [Cu (SMZ-CAL)2], and [Ni (SMZ-CAL)2]. The samples exhibited significant radical scavenging activity, indicating their potential as antioxidants. [Cu (SMZ-CAL)2] demonstrated the highest potency among the tested compounds. This study contributes to the advancement of medicinal chemistry by exploring the synthesis and characterization of novel metal complexes with unique structural features. The findings provide valuable information for the development of new pharmaceuticals with improved pharmacological characteristics.