Synthesis And Studies On Properties Of Hydrazone Schiff-base Containing Pyridine Rings And Its Transition Metal Complexes

In the past half a century, Nitrogen-containing heterocyclic acyldrazones compounds as special schiff base, have strong coordination ability, good biological activities, superconduct functional materials and other excellent properties, make them and their complexes have been received a great deal of attention.Based on this point, two kinds of mono- and diacyldrazones containing pyridine rings have been prepared in this paper, all of their metal complexes have been characterized by elemental analysis, UV-vis, IR, molar conductivity and X-ray single crystal diffraction. The ligands were also identified by ¹H-NMR and MS additionally. The full-optimized molecular geometries of the two Diacyldrazones were calculated atB3LYP/6-31G level with Gaussian 03W program. The main research in this paper included:1. Two monoacyldrazones were synthesized with 2-pyridinecarboxaldehyde as material. They were 2-pyridinecarboxaldehyde-salicyloylhydrazone (H₂L1), 2-pyridine-carboxaldehyde-p-hydroxybenzohydrazone (H₂L2). Ten complexes containing these ligands of Cd (II),Cu (II),Mn (II),Ni (II),Zn (II) were prepared and two single crystals of complexes([Cd(L1)₂]₂.Py and [Ni(L1)₂]₂·CH₃OH) were obtained in mixed solvent of Pyridine/DMF and methanol/DMF (Py = pyridine, DMF = N,N-dimethylformamide), respectively. Two single crystals were obtained accidentally during the experiment.2. Two diacyldrazones were synthesized with pyridine-2,6-dicarbohydrazide as mediate. They were 2,2'-Bis(3,5-dibromosalicylahyde)pyridine-2,6-dicarbohydrazide (H₄L3) and 2,2'-Bis(2-nitrobenzylidene)pyridine-2,6-dicarbohydrazide(H2L4). Ten complexes containing these ligands were prepared. An unexpected single crystal of rare-earth metal complex (comp-Eu) was obtained in mixed solvent of water/DMF by solvothermal synthesis. Three single crystals of two ligands and one mediate were obtained by solvent diffusion method. According to literatures, we also discussed the various coordinational modes of the diacyldrazones and speculated the configuration of their complexes.Property measurement: Epoxidation of styrene catalyzed by their manganese complexes of the two ligands(H₂L1 and H₄L3)as model compounds of oxygenase has been studied, the former showed better catalytic activities; The electrochemical activities of nickel were studied respectively in the solvent of methanol and DMF, the electrochemical stability of complexes were better in the solvent of DMF; H₂L1, H₄L3 and their cadmium complexes revealed obvious fluorescence activities, the activities of H₄L3 and its cadmium complexes were better because of their bigger system.