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Design and Synthesis of Imidazole-Based Ligand and Its Metal Complexes: Spectroscopic Characterization and Evaluation of Antibacterial, Antioxidant and Hemolytic Activities

Howraa A. Khudair1, Sawsan K. Abbas2, Suhad K. Abbas1
Affiliation: 
Department of Chemistry, College of Science, University of Kerbala, Karbala, Iraq1 2Department of Chemistry, College of Education for Pure Science, University of Kerbala, Karbala, Iraq suhad.k@uokerbala.edu.iq
DOI: 
https://doi.org/
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Keywords:

Abstract: 
In this study, new complexes containing a multi-substituted aryl imidazole ligand, namely (2-(1H-phenanthro[9,10-d] imidazol-2-yl) phenol, have been synthesized. Imidazole ligand L was synthesized via a condensation reaction between diketone (9,10-phenathroquinone), aromatic aldehyde (2-hydroxy benzaldehyde), and ammonium acetate in the presence of glacial acetic acid as a solvent and catalyst. Subsequently, metal complexes were prepared by reacting this ligand with transition metal salts, including Fe (II), Cu (II), Ni(II), and Co(II) chlorides, in an appropriate solvent like ethanol under controlled temperature and stirring conditions to ensure the formation of stable complexes. The structures of the ligands and their metal complexes were characterized utilizing different spectroscopic techniques, such as (UV-Vis), FT-IR, 1H NMR, 13C NMR spectroscopic, mass spectroscopy, magnetic susceptibilities, molar conductivity, and elemental analysis (C.H.N). It is observed that the synthesized complexes have tetrahedral and octahedral geometrical structures. The ligand and its complexes play important roles in supramolecular assemblies because they can also provide bidentate N-donor sites for chelating with metal ions to form a bridge ligand. The biological evaluation was performed using the agar well diffusion method to assess the antibacterial activity of both ligand and metal complexes against selected Gram-positive and Gram-negative bacterial strains. The results revealed that the free ligand and its metal complexes displayed significantly enhanced antibacterial activity compared to the reference drug. Antioxidant potential was assessed using the DPPH radical scavenging assay; metal complexes generally showed higher radical inhibition percentage. Hemolytic activity was evaluated on human red blood cells to determine cytocompatibility. The findings showed that the ligand and metal complexes exhibited low to moderate hemolytic activity, indicating acceptable biocompatibility for potential biomedical applications.
References: 

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