Synthesis, Characterization And Properties Of Aryl-acylhydrazone Ligands And Their Metal Complexes

In this dissertation, several aryl-acylhydrazones were synthesized, by the reaction of benzoyl hydrazine,2-hydroxy benzoyl hydrazine or 4-hydroxy benzoyl hydrazine with naringenin or 8-acetyl-7-hydroxy-4-methyl coumarin, separately. And melting point, NMR, and mass spectra were used to confirm these organic ligands.Later, the metal complexes of these organic ligands were prepared. Elemental analyses (C, H, N) and metal titration with EDTA were used to determine the component of the complexes. Infrared spectra and molar conductance measurements were used to presume the coordination structures.Finally, pharmacological properties or fluorescence properties of the ligands and the metal complexes were studied. For instance, the interaction with calf thymus DNA (CT-DNA) and antioxidant activities of the ligands and the metal complexes were investigated.In chapter 1, a simple review was made, including:the basic structure of DNA (deoxyribonucleic acid), the interaction of small molecules with DNA (interaction mode and detecting methods), some information about reactive oxygen species (generation methods and detecting methods in vitro), and some characters of flavonoid and coumarin.In chapter 2, a ligand, naringenin (2'-hydroxy benzoyl) hydrazone, was synthesized by the reaction of naringenin with 2-hydroxy benzoyl hydrazine. And its Cu(â…¡), Zn(â…¡), Ni(â…¡) complex have also been prepared and characterized. Finally, the antioxidant activities (superoxide radical and hydroxyl radical scavenging activities) of the free ligand and its complexes were determined in vitro. These compounds were found to possess good antioxidant activity. In particular, the Cu(â…¡) complex displayed excellent activity on the superoxide radical.In chapter 3, Y(â…¢) complex and Eu(â…¢) complex of the naringenin (2'-hydroxy benzoyl) hydrazone were synthesized. Experimental evidences indicate that these three compounds can strongly bind to CT-DNA via an intercalation mechanism. For the interaction ability with DNA, Eu(â…¢) complex was better than Y(â…¢) complex and the free ligand. Furthermore, the hydroxyl radical scavenging activities of the Y(â…¡) complex and Eu(â…¢) complex were lower than the free ligand and the Cu(â…¡), Zn(â…¡), Ni(â…¡) complexes of the ligand.In chapter 4, first,8-acetyl-7-hydroxy-4-methyl coumarin was prepared. Then by the reaction of 8-acetyl-7-hydroxy-4-methyl coumarin with benzoyl hydrazine or 4-hydroxy benzoyl hydrazine separately, two ligands,7-hydroxy-4-methyl-8-acetyl coumarin (benzoyl) hydrazone and 7-hydroxy-4-methyl-8-acetyl coumarin (4'-hydroxylbenzoyl) hydrazone, were synthesized. The Cu(II), Zn(II) complexes of the two ligands were also prepared. Finally, the interaction of the ligands and the metal complexes with CT-DNA was investigated. Experimental data shown that Cu(II), Zn(II) complexes bound with CT-DNA by different mode.In chapter 5, a new coumarin derivative was got, by using 7-hydroxy-4-methyl coumarin was used as staring material. And its Eu(III) and Tb(III) complexes were also prepared. Fluorescence emission spectrum shown that Eu(III) complex can give characteristic emission of Eu(III) ion.In chapter 6, a fluorescein-based colorimetric chemosensor,1-phenyl-3-methyl-5-hydroxypyrazole-4-benzoyl (fluorescein) hydrazone, was synthesized by the reaction between fluorescein hydrazide and 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone. And its sensing behavior toward metal ions was investigated. Addition of Cu2+ to an aqueous solution of the chemosensor made the color change from colorless to deep yellow in a very short time. However, under the same conditions, other common alkali- alkaline earth-, transition-and rare earth metal ions induced no or very little color change. The stoichiometry, association constant, and binding mode of the chemosensor with Cu2+ were also investigated.