Synthesis, spectral characterization and antioxidant activity studies of a bidentate Schiff base, 5-methyl thiophene-2-carboxaldehyde-carbohydrazone and its Cd(II), Cu(II), Ni(II) and Zn(II) complexes

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 101; pp. 264 - 272
• Main Authors: Harinath, Y., Harikishore Kumar Reddy, D., Naresh Kumar, B., Apparao, Ch, Seshaiah, K.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15-01-2013
• Subjects: Aldehydes - chemical synthesis; Aldehydes - chemistry; Aldehydes - pharmacology; Anti-Infective Agents - chemical synthesis; Anti-Infective Agents - chemistry; Anti-Infective Agents - pharmacology; Antioxidant activity; Antioxidants - chemical synthesis; Antioxidants - chemistry; Antioxidants - pharmacology; Bacteria - drug effects; Bacterial Infections - drug therapy; Cadmium - chemistry; Cadmium - pharmacology; Coordination Complexes - chemical synthesis; Coordination Complexes - chemistry; Coordination Complexes - pharmacology; Copper - chemistry; Copper - pharmacology; Fungi - drug effects; Humans; Hydrazones; Hydrazones - chemical synthesis; Hydrazones - chemistry; Hydrazones - pharmacology; Microbial assay; Microbial Sensitivity Tests; Mycoses - drug therapy; Nickel - chemistry; Nickel - pharmacology; Schiff Bases - chemical synthesis; Schiff Bases - chemistry; Schiff Bases - pharmacology; Thiophenes - chemical synthesis; Thiophenes - chemistry; Thiophenes - pharmacology; Transition metal complexes; Zinc - chemistry; Zinc - pharmacology; Hydrazones; Transition metal complexes; Antioxidant activity; Microbial assay
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2012.09.085

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► Synthesis of new hydrazone metal complexes which possess anti oxidant activity. ► Ligand is coordinated to the metal ions in bidentate manner with the azomethine-N and carbonyl-O. ► The stoichiometry of the metal complexes is [M(L)2X2] (where X=Cl). ► Spectral studies showed orthorhombic geometry for the complexes. ► Copper complex exhibited higher in vitroantioxidant and antimicrobial activity.
A new Schiff base bidentate ligand (L), 5-methyl thiophene-2-carboxaldehyde-carbohydrazone and its metal (Cu(II), Cd(II), Ni(II) and Zn(II)) complexes with general stoichiometry [M(L)2X2] (where X=Cl) were synthesized. The ligand and its metal complexes were characterized by elemental analyses, IR, 1H NMR, ESR spectral analyses, and molar conductance studies. The molar conductance data revealed that all the metal chelates are non-electrolytes. IR spectra showed that ligand (L) is coordinated to the metal ions in a bidentate manner with N and O donor sites of the azomethine-N, and carbonyl-O. ESR and UV–Vis spectral data showed that the geometrical structure of the complexes are Orthorhombic. Furthermore, the antioxidant activity of the ligand and its complexes was determined by hydroxyl radical scavenging, DPPH, NO, reducing power methods in vitro. The obtained IC50 value of the DPPH activity for the copper complex (IC50=66.4μm) was higher than other compounds. Microbial assay of the above complexes against Staphylococcus aureus, Escherichia coli, Rhizocotonia bataticola and Alternaria alternata showed that copper complex exhibited higher activity than the other complexes.