Synthesis, Crystal Structure, Characterization And Properties Of Triazole, Pyrazine Ligands And Complexes

In recent years, coordination compounds with novel structure topological havepotential applications in functional materials and molecular recognition,have causedgreat attention. 1,2,4-triazole and pyrazine derivatives with many advantages:strongcoordination ability, more coordination points and more patterns, can be bridging invarious ways with metal ions and other bridging ligand, widely used in theconstruction of the functional complexes.In this study,two 3,5 - disubstituted-1,2,4 - triazoles and one pyrazine-amideligands have been synthesized, a kind of 3,5- disubstituted -1H-1,2,4 - triazolescomplex with transition metales has also been synthesized and characterization bymelting point,IR, 1H-NMR and X-ray crystal diffraction, thermal stability andmagnetic susceptibility of the complex have been conducted.Our main works are as follows:1. 3,5- bis (hydroxymethyl) -1,2,4– triazole was chosen as ligand.Its binuclearcobalt Co(Ⅲ)complex was synthesized and the crystal structure of the complexeswere analyzed .We found that specific hydrogen bonding pattern of 3,5 - bis(hydroxymethyl) -1,2,4 - triazole ligands is an important factor for the bonding modeof center metal ions.The thermal properties of the complex have been studied.Itsmagnetic susceptibility has also been predicted.2. 4-amino-3, 5 - bis (mercapto methyl) -1, 2,4 - triazole flexible ligandsynthesized with glycolic acid and hydrazine hydrate by three reaction steps:condensation, chlorination and thiol reaction. As a new flexible triazole ligand,hasnot been synthesized and reported before.It has been characterization by melting point,elemental analysis,infrared spectroscopy and 1H-NMR spectroscopy.Synthesisconditions, spectroscopic properties and functional applications were characterizedand discussed.3. 3,5 - disubstituted -1,2,4 - triazole Schiff base ligand containing pyridine ringsynthesized with acetic acid and hydrazine hydrate by condensation, and thenoxidation to triazole carboxylic acid, triazole carboxylic acid reacted with hydrazinehydrate and then further esterification reaction occurs to hydrazine. By reaction ofdisubstituted triazole hydrazine with 2 - pyridine - formaldehyde, synthesized by traditional methods. Characterized by melting point, elemental analysis, infraredspectroscopy, 1H-NMR spectroscopy. Its synthesis conditions, spectroscopicproperties and other properties have been discussed.4. Pyrazinamide synthesized by two-step reaction with pyrazine 2,3 - dicarboxylicacid as raw material, through esterification, amidation, the compounds wascharacterized by the melting point, elemental analysis , infrared spectroscopy (IR),proton nuclear magnetic resonance spectroscopy (1H-NMR),its composition andcoordination mode have been discussed.