Synthesis And Property Study Of Rare Earth Complexes With 2-Carboxybenzaldehyde-2, 4-dinitrophen Hydrazone

According to the theoretic significance and the applications of the complexes, this paper mainly concluded the following work:The ligand, 2-carboxybenzaldehyde-2,4-dinitrophen hydrazone, was synthesized by 2-carboxybenzaldehyde and 2,4-dinitrophenyl hydrazine in absolute alcohol.The novel thirteen complexes were synthesized by the reaction of 2-carboxybenzaldehyde-2,4 -dinitrophen hydrazone and rare earth nitrate(RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb and Y) in methanol solution.The chemical formula of C14H10N4O6 and RE(C14H9N4O6)(C14H8N4O6)·4H2O were determined by elemental analysis, IR, UV, FS and X-ray powder diffraction. The results showed that one ligand was coordinated in the form of negative one value, the other was coordinated in the form of negative two value, and two stable eight membered rings were formed by N atom(N-H) and O atom(C-O of COOH) with the rare earth(III). Some of the complexes possessed strong fluorescence characteristics.The thermal decomposition of the ligand (C14H10N4O6) and the complexes RE(C14H9N4O6) (C14H8N4O6)·4H2O were carried out by TG-DTG analysis at 5, 10 and 15 K·min-1 respectively. The Kissinger and Ozawa's method were used to calculate the apparent activation energies and kinetics parameters of the thermal decomposition stages of the ligand and the complexes. The results showed that the activation energies (E) and correlation coefficient (r) of the ligand and the complexes calculated by the two methods were in good agreement, the complexes had higher thermal decomposition temperature and the thermal stability was higher than the ligand.The biological activity of the ligand (C14H10N4O6) and the complex Sm(C14H9N4O6) (C14H8N4O6)·4H2O to Staphylococcus aureus ATCC 6538 were carried out. The results showed that the complex Sm(C14H9N4O6)(C14H8N4O6)·4H2O had stronger bacteriostatic activity to Staphylococcus aureus ATCC 6538 than the ligand; and the antibacterium rate of Sm(C14H9N4O6)(C14H8N4O6)·4H2O to Staphylococcus aureus ATCC 6538 was 92% with respect to zero of the ligand. It is obvious that the bacteriostatic activity of the ligand was strenghthened after the coordination with Sm.