论文部分内容阅读
In order to study the coordination character of the rare earth elements with hydrazones and the antioxidative activity of the ligand and the complexes, 3,5 dibenzyloxybenzoyl 2,4 dihydroxybenzaldehyde hydrazone (H 2L), a new chelating ligand, and its six lanthanide complexes, Ln (HL)(OAc) 2· n H 2O [Ln=La, Sm, Eu, Gd, Tb, Dy; n =2, 4, 5], were synthesized and characterized on the basis of elemental analyses, IR and 1H NMR spectra, molar conductivity. The results show that the lanthanide ions are coordinated by O, O and N donors of the phenol (Ar OH) without deprotonation, the enol oxygen of the hydrazone group (NCO -) and the azomethine group (CH=N) from the ligand respectively, and by the four carboxylic oxygen from two acetate groups (CH 3COO -) in the bidentate form. The scavenging activity of the ligand and the six lanthanides complexes on the 2,2 Diphenyl 1 picrylhydrazyl (DPPH) free radicals is also evaluated. The results show that both the ligand and the complexes have the scavenging activity on the DPPH radicals, and the scavenging activity of the complexes is better than the ligand.
In order to study the coordination character of the rare earth elements with hydrazones and the antioxidant activity of the ligand and the complexes, 3,5 dibenzyloxybenzoyl 2,4 dihydroxybenzaldehyde hydrazone (H2L), a new chelating ligand, and its six lanthanide complexes, Ln (HL) (OAc) 2 · n H 2O [Ln = La, Sm, Eu, Gd, Tb, Dy; n = 2, 4, 5] were synthesized and characterized on the basis of elemental analyzes, IR and 1H NMR spectra, molar conductivity. The results show that the lanthanide ions are coordinated by O, O and N donors of the phenol (Ar OH) without deprotonation, the enol oxygen of the hydrazone group (NCO -) and the azomethine group (CH = The scavenging activity of the ligand and the six lanthanides complexes on the 2,2 diphenyl 1 picrylhydrazyl (DPPH) free radicals is also evaluated. The results show that both the ligand and th e complexes have the scavenging activity on the DPPH radicals, and the scavenging activity of the complexes is better than the ligand.