Some new antimicrobial/antioxidant nanostructure zinc complexes: Synthesis, crystal structure, Hirshfeld surface analyses and thermal behavior

In this study, the synthesis and characterization of a new bidentate ligand and some its zinc halide/pseudohalide complexes and nano-structures are described. The crystal structures of the ligand and its zinc nitrate complex as typical examples were determined by single crystal X-ray diffraction. Hirshfeld surface analysis of these structures provided insight into the various intra and inter-molecular interactions and therefore a description of the supramolecular structure for the ligand and its zinc nitrate complex in solid state. Furthermore, the thermal behavior of the complexes was established by TG/DTG/DTA curves analysis. Moreover an antibacterial bioassay of the zinc complexes was been performed in vitro against two gram-positive (Staphylococcus aureus and Bacillus subtilis) and two gram negative (Escherichia coli and Pseudomonas aeruginosa)] bacterial strains. The antifungal activities of the compounds against two fungal strains of Aspergilus niger and Candida albicans were also investigated. The antioxidant capabilities of the Schiff base ligand and its zinc complexes were determined by the in vitro methods of ABTS and DPPH as compared with the standard Trolox. Finally, ZnO nanoparticles were synthesized by direct calcination of the zinc iodide complex at 550 ◦C under air atmosphere confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDX).