Design, Synthesis And Properties Of Pyrazolecarboxylic Acid Derivatives And Their Complexes

Coordination compounds of pyrazolecarboxylic acid derivatives are multiplex and multifunctional complexes, they have potential applications in catalysis, adsorption, enzyme and functional materials, and so on. The study of pyrazolecarboxylic acid derivatives and their complexes have always been attracted tremendous attention in recent years.In this paper, four bis(pyrazolyl)methane derivatives, namely:bis(5-diethoxycarbo-nyl-1-pyrazolyl)methane (5-bdepm, L1), bis(3(5)-diethoxycarbonyl-l-pyrazolyl)methane (3(5)-bdepm, L2), bis(3-diethoxycarbonyl-l-pyrazolyl)methane (3-bdepm, L3) and bis(3,5-diethoxycarbonyl-l-pyrazolyl)methane (3,5-bdepm, L4) were successfully synthesized, and characterized by IR,1H-NMR, MS spectrum as well as single-crystal X-ray diffraction.Four different complexes:[Cu(Hpc)2(H2O)2]·2H2O (1), [Co(Hpc)2(H20)2] (2), [Ni(Hpc)2(H2O)2] (3) and [CdCl(Hpc)H2O]n(4) were obtained by the reaction of 1H-pyrazole-3-carboxylic acid (H2pc) with different metal salts, and structurally characterized by IR spectrum, UV-Vis spectrum, elemental analysis, single-crystal X-ray diffraction. The single-crystal X-ray diffraction reveals that complex 4 is 2D-net polymer, while the others are mononuclear.Six novel coordination polymers were successfully prepared under solution or hydrothermal method using bis(pyrazolyl)methane ligands, mainly{Cu[(5-bdcmp]H20}∞(5)、 [Cu(3(5)-bdcpm]∞ (6)、[Ag(3-bdepm)NO3]∞ (7)、{[Cu2(3,5-bdcmp)(H2O)4]·2H2O}∞, (8)、 [Co(3,5-bdcmp)(H2O)3]2·(H2O)2 (9) and [Ni(3,5-bdcmp)(H2O)3]2·(H2O)2 (10). Bis(diethoxycarbonyl-1-pyrazolyl)methane (bdepm) was in suit hydrolyzed into bis(dicarbonyl-l-pyrazolyl)methane (bdcpm) which in turn binds the metal centers to generate complex. The single-crystal X-ray diffraction reveals that complex 5 is 2D-net polymer,6,7 and 8 are 1D chain polymers, while 9 and 10 binuclear.Besides, we have studied the thermal stabilities of complexes 1,2,3 and 4. At the same time, we have also studied the fluorescent properties of complexes 6,7 and 8.