Synthesis, investigation, and biological activity of novel Zn(II) and Fe(III) complexes of cyanohydrazone derivatives ligand.

This study involves the synthesis and characterization of zinc(II) and iron(III) complexes of cyanohydrazone-based ligands (H2L). The structure of the resulting chelates were elucidated through a combination of elemental analysis, magnetic measurements, infrared spectroscopy, and UV- Vis techniques, offering insight into the coordination environment and geometry. Density Functional Theory (DFT) was applied to optimize and propose the most possible molecular geometries of both complexes and exhibits that the complex of zinc(II) had tetrahedral geometry, whereas the complex of Fe(III) had octahedral geometry. Thermal analysis of [Zn(L)(H2O)]·0.5H2O and [Fe(HL)2(H2O)2]Cl·2H2O complexes was performed to investigate their decomposition behavior, from which kinetic and thermodynamic parameters were extracted using the Horowitz–Metzger and Coats–Redfern models. Furthermore, the synthesized compounds were screened for biological activities, including antioxidant potential using the 2,2- Diphenyl -1- picrylhydrazyl (DPPH) free radical method and antibacterial efficacy against selected microbial strains. The findings support promising bioactivity and stability profiles, offering potential applications in biomedical and pharmaceutical fields.