Synthesis And Properties Of Novel Triazole Compounds And Their Complexes With Europium And Terbium

Triazole compounds are paid much attention in the fields of material and drug because oftheir well coordination and special biological activity, so it has great significance to carry outthe research and application development of triazole compounds. In this paper, a series ofnovel1,2,4-triazolo[3,4-b]-1,3,4-thiadiazol compounds and their complexes with Eu(Ⅲ) orTb(Ⅲ) have been synthesized, the luminescent and electrochemical properties of thecomplexes were respectively investigated by luminescent spectra and cyclic voltammetry.Meanwhile, a series of novel1,2,4-triazoles Schiff bases were synthesized, and theirbiological activity was investigated by the gelatin zymography. The main research works areas follows:(1) With2,6-pyridine dicarboxylic acid as starting material, a series of1,2,4-triazolo[3,4-b]-1,3,4-thiadiazol derivatives was synthesized by the reaction of esterification,hydrazinolysis and cyclization successively, characterized by1H NMR, MS, FT-IR spectrumand elemental analysis. Their complexes with Eu(Ⅲ) or Tb(Ⅲ) was prepared, and themolecular structures were determined by the way of elemental analysis, EDTA titrimetricmethod, molar conductance, UV and FT-IR spectrum as well as thermal studies.(2) The fluorescence quantum yields of the objective complexes were calculated by thereference method, and the luminescent and electrochemical properties of the complexes wererespectively investigated by luminescent spectra and cyclic voltammetry, and the relation ofthe property of the complexes to the structure of ligands was discussed. The resultsdemonstrated that all complexes show the characteristic luminescent of central ion with goodmonochromaticity and high intensity, and the central ion is not in the center of symmetry.Compared with the complex without substituent group, the complex substituted by electronwithdrawing group possesses higher luminescent intensity and fluorescence quantum yield,the energy level of which is lower, while the complex substituted by electron donating grouppossesses lower luminescent intensity and fluorescence quantum yield, the energy level ofwhich is higher. The complexes with chlorine substituent group show remarkable luminescentproperty.(3) Starting from4-picolinic acid, the objective1,2,4-triazoles Schiff bases wereprepared via the reaction of esterification, hydrazinolysis, cyclization and condensationsuccessively. The objective compounds as well as their intermediates were characterized by1H NMR, MS, elemental analysis and FT-IR spectrum. The effect of the reaction conditionssuch as solvent, catalyst, temperature, time and mole ratio of reactants on the yields of theobjective compounds were investigated, respectively. The optimum synthesis conditions are that the solvent and catalyst of reaction is glacial acetic acid, the reaction temperature is120℃, the reaction timeis7h, and the mole ratio of2-(4-amino-5-(4-pyridyl)-1,2,4-triazole-3-mercapto)-N-(4-substituent-phenyl)-acetamide and salicylaldehyde is4to5.(4) The objective compounds were screened for their inhibition to the activity ofgelatinase by the gelatin zymography, and the relationships between the structure and thebiological activity of the compounds were investigated. The results showed that the series of1,2,4-triazoles Schiff bases possess the inhibiting capacity to the activity of gelatinase.Compared with the compound without substituent group, the compound substituted byelectron withdrawing group possesses higher biological activity, and the compoundsubstituted by electron donating group possesses lower biological activity.