Synthesis, Characterization And Bioactivity Of Oxygen-containing Aromatic Ring Schiff-base Ligands And Their Metal Complexes

In this paper, we have reported mainly the synthesis, characterization and bioactivity of oxygen-containing aromatic ring Schiff-base ligands and their Schiff-basemetal complexes. Three kinds of Schiff-base ligands condensed from three kinds of aromatic aldehydes and their 12 metal complexes have been synthesized. This paper is composed of six chapters:In the first chapter, we summarize progress in pharmacological research of coumarins and flavonoids and interactions of metal complexes with antioxidant and DNA-binding.In the second chapter, the 2-carboxybenzaldehyde-(2 -hydroxy)benzoylhydrazone Schiff-base ligand H₂L¹ and its four rare earth (La³⁺, Sm³⁺, Eu³⁺, Nd³⁺) complexes have been synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra, ¹H NMR spectra and so on. In addition, the suppression ratio for OH^·and O₂^- were determined with 721 spectrophotometer.In the third chapter, the 7-methoxychromone-3-carbaldehyde-benzoylhydrazone Schiff-base ligand HL² its four rare earth (La³⁺, Sm³⁺, Eu³⁺, Dy³⁺) complexes have been synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra, ¹H NMR spectra and so on. In addition, the suppression ratio for OH^·and O₂^- were determined with 721 spectrophotometer.In the fourth chapter, the 8-methylcoumaro-4a,10a-pyrone-3-carbaldehyde-benzoylhydrazone Schiff-base ligand HL³ and its three transition metal (Cu²⁺, Ni²⁺, Co²⁺) complexes have been synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra, ¹H NMR spectra and so on. In addition, the suppression ratio for OH^·and O₂^- were determined with 721 spectrophotometer.In the fifth chapter, we mainly investigate the interactions of the ligands HL², HL³ and [CuL²(H₂O)]Cl·2H₂O, [Cu(HL³)(H₂O)Cl₂] with calf thymus DNA.In the sixth chapter, we mainly investigate the interactions of the ligand HL² and [Ln(HL²)₂(NO₃)₃]·H₂O (Ln= La³⁺,Eu³⁺) with calf thymus DNA.In the research of the antioxidant activity, it is found that the synthetized Schiff base ligands and their metal complexes all have scavenger ability of OH^·and O₂^- and the ability of antioxidant activity of compounds maily depends on the structure of compounds. In addition, the characteristics of metal ions in the transition metal complexes of antioxidant activity perform significantly.In the research of the interaction of compounds with calf thymus DNA, the results show that aromatic ring containing chromones and coumarins compounds bind to thymus DNA by intercalation mode and the binding affinity of the compounds to thymus DNA not only depends on the size of the aromatic ring containing the plane area, but also depends on the spatial structure and biological activity of the compounds.