Synthesis, Characterization, And Biological Evaluation Of (2-Chlorobenzylidene) Hydrazono) Butan-2-One Oxime Ligand And Its Inner Transition Metal Complexes

Abstract

The synthesis and characterization of a novel ligand, (2-chlorobenzylidene)hydrazono)butan-2-one oxime (CHBO), and its inner transition metal complexes with La(III), Nd(III), Sm(III), and Gd(III) are reported. The CHBO ligand was synthesized through the condensation of 2-chlorobenzaldehyde and hydrazonobutan-2-one oxime under optimized reaction conditions. The structural elucidation of the ligand and its complexes was performed using various spectroscopic techniques, including Fourier-transform infrared (FTIR), ultraviolet-visible (UV-Vis), nuclear magnetic resonance (NMR), and mass spectroscopy, along with thermal analysis and elemental studies. Magnetic susceptibility and molar conductivity measurements were also employed to ascertain the geometry and coordination environment of the complexes.

The results suggest that the ligand coordinates through the azomethine nitrogen, oxime oxygen, and ketonic oxygen, forming stable chelates with octahedral and square planar geometries, depending on the metal ion. The antimicrobial and antifungal activities of the ligand and its complexes were assessed against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Candida albicans, and Saccharomyces cerevisiae. The complexes exhibited enhanced biological activity compared to the free ligand, attributed to the increased lipophilicity and efficient coordination with metal ions.

These findings demonstrate the potential of CHBO and its metal complexes as promising candidates for antimicrobial applications, emphasizing the role of transition metal coordination in improving biological efficacy. The structure-activity relationships (SAR) of these compounds are also discussed to provide insights for future research in the development of bioactive coordination complexes.