The Design, Synthesis, Characterization And Property Of Complexes Based On N-heterocyclic Pyrazole Derivatives

Recently, considerable research efforts have been directed towards the pyrazole derivatives and their complexes not only because of their fascinating structural diversities, but also due to their potential applications in ion exchange, biological activities, magnetic, porous materials, catalysts, and luminescent materials. In additional, N-heterocyclic pyrazole derivatives is a good example of N-and O-donors ligands and regarded as one kind of elegant ligands to build the supramolecular complex structures.In this paper, three N-heterocyclic pyrazole ligands:5-(pyridin-3-yl)-1H-pyrazole-3-carboxylic acid (HL1),5-(pyridin-4-yl)-1H-pyrazole-3-carboxylic acid (HL2) and 5-(Pyrazin-2-yl)-1H-pyrazole-3-carboxylic acid (HL3) were synthesized by 1-(pyridin-3-yl)ethanone, 1-(pyridin-4-yl)ethanone and 1-(pyrazin-2-yl)-ethanone, respectively. The compounds have been characterized by elemental analysis, NMR, FT-IR spectrum.One 2D coordination polymers{[Cu(L1)2]-(DMF)(H2O)}n (1) was obtained by the reaction of HL1 ligand and CuBr under solution method. Another 2D coordination polymers [Co(L1) (H20)Cl]n (2) was synthesized by the reaction of HL1 ligand and COCl2·6H2O under solvothermal conditions. Furthermore, the thermal stability of the complexes was studied.The reaction of HL2 ligand and CoCl2·6H2O) under various conditions, such as chaging the pH value, reaction temperature, solvents, adding the auxiliary ligands, the ratio between metal and ligand, resulted four complexes, [Co(L2)2(H2O)2] (3), [Co(L2)2]n (4),{[Co(L2)2]·(bipy)}n (5), [Co(L2)(H2O)Cl]n (6). And two complexes, [Ni(L2)2]n (7), [Zn(L2)2]n (8) were obtained by HL2 and NiCl2·6H2O, ZnBr2 metal salts under solvothermal conditions, respectively. The complexes 4,5,7,8 possess the 2-D layer structure, and complex 6 possesses the 3-D layer structure. In addition, the complexes 3-5 were analyzed by thermogravimetric.There two complexes [Co(L3)2(H2O)]n (9), [Cd(L3)2(H2O)3] (10), were synthesized using HL3 ligand and COCl2·6H2O, Cd(C104)2·6H20 under solvothermal method, respectively. And the structures were characterized by element analysis and the X-ray diffraction tecnology for single crystal.