Synthesis and Characterization of Mixed Ligand Complexes Involving Miconazole and Salicylhydrazide with Transition Metals: Evaluation of Antibacterial and Antifungal Properties

In this study, a series of mixed-ligand transition metal complexes were synthesized using Miconazole (MCZ) and Salicylhydrazide (SH) with Cu(II), Ni(II), Zn(II), Co(II), and Cd(II) ions in ethanolic medium. The complexes were characterized by elemental analysis, FTIR, UV-Vis spectroscopy, magnetic susceptibility, molar conductivity, and powder XRD. The data support the formation of octahedral complexes, with MCZ acting as a monodentate ligand through imidazole nitrogen and SH as a bidentate ligand via C=O and NH₂ groups. Notably, the Ni(II) complex displayed 1:2 electrolyte behavior, distinct from other neutral complexes. XRD analysis confirmed nanoscale crystallinity (33–79 nm), except for the Co(II) complex, which exhibited amorphous characteristics. Antimicrobial activity was assessed against Staphylococcus aureus, Escherichia coli, Candida albicans, Penicillium italicum, and Aspergillus niger using the agar well diffusion method. The Zn(II) complex demonstrated the most significant antibacterial and antifungal activity, with inhibition zones up to 17.5 mm, surpassing both free ligands and other metal complexes. This enhancement is attributed to increased lipophilicity and reduced particle size. In contrast, Ni(II) and Co(II) complexes exhibited limited activity, particularly against Candida albicans. These findings suggest that metal coordination notably influences antimicrobial efficacy and underscore the potential of Zn(II)-based complexes for further therapeutic exploration.