Structural, DFT, Molecular Docking and Biological Activity of New Albendazole‐Norfloxacin Mixed‐Ligand Complexes: Promising Metal Complexes for Combating Microbial Resistance and Inflammation

Abstract

This study presents a comprehensive characterization of the Fe(III)(C1) and Co(II)(C2) complexes were synthesized from the Albendazole (Alb) and Norfloxacin (Nor) ligands. The complexes exhibit remarkable thermal stability, low water solubility, and a non‐electrolytic nature, characteristics that enhance their suitability for diverse applications. Conductivity measurements indicate molar conductivities of 9.85 and 8.59 Ω−1cm²mol−1,confirming their status as neutral molecules. Fourier Transform Infrared (FTIR) spectroscopy reveals significant ligand‐metal interactions, marked by shifts in vibrational frequencies that confirm chelation, while Ultraviolet‐Visible (UV‐Vis) spectroscopy supports the identification of octahedral geometries for both complexes. Magnetic moment assessments align with their electronic configurations, and stoichiometric analysis consistently shows a 1:1:1 ratio, further validated by mass spectrometry. Thermal stability studies highlight anhydrous characteristics and distinct thermal decomposition behaviors, underscoring their structural integrity. Employing Density Functional Theory (DFT) calculations using the B3LYP functional, we evaluate the electronic properties of the ligands and their metal complexes, revealing reduced energy gaps (ΔE) of 2.29 eV for C1 and 2.15 eV for C2, significantly lower than those of the ligands (Alb: 4.61 eV, Nor: 4.17 eV), indicating enhanced reactivity and potential biological activity. Additionally, molecular electrostatic potential (MEP) maps provide insights into charge distributions, suggesting critical regions for interactions with biomolecules.