Synthesis Characterization and Biological Evaluation of Metal Complexes Derived From Schiff Bases

Abstract

Condensation of carbonyl compounds with primary amines is one of the traditional reactions in chemistry, leading to the formation of Schiff base compounds. Transition metal complexes having N2O2 donor Schiff bases play a vital role in pharmaceutical, biological and industrial chemistry, due to their diverse applications as contrast enhancing agents in NMR imaging, luminescent probes in medicine and biology, radio metal-labeled agents for diagnostic imaging, catalyst, supramolecular assemblies with enhanced physiochemical properties. newlineWith these objectives in mind, Schiff base transition metal complexes are synthesized and characterized. In addition, the Schiff base ligands and their metal complexes are screened for their invitro antimicrobial activities against Salmonella Typhi, Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa. The antioxidant activity of Schiff base ligands was analyzed by 2,2-Diphenyl-1-Picryl Hydrazyl (DPPH) and Hydroxyl radical scavenging method. Further, the antioxidant activities of Schiff base metal complexes were determined by the reduction of 1,1-diphenyl-2-picyl hydrazyl (DPPH). These studies exhibited that, the Schiff base ligands possessed better antioxidant activity than their metal complexes. newlineThe experimental part of this thesis includes the synthesis of fifteen Schiff base ligands (L1-L15) by Condensation reaction. 2-acetyl-1-naphthol and its derivatives are reacted with different aliphatic diamines. The corresponding Schiff base metal complexes are synthesized by using transition metal ions. The structure elucidation of the synthesized Schiff base ligands and their transition metal complexes were confirmed by FT-IR, 1H NMR, 13C NMR, Mass spectral analysis. The physical characterization of synthesized Schiff base metal complexes was done by UV-Visible, PXRD, TGA-DTA and ESR techniques. The typical procedure and experimental setup for anti-bacterial and antioxidant studies has been incorporated in chapter 5. The UV-Visible, P-XRD, TGA-DTA and ESR newlineA