Synthesis, Characterization And Properties Of Metal Complexes Based On Pyrazole And Triazole Hydroxamic Acid

Hydroximic acid is easy to chelate a variety of transition metal and main group metal to form stable coordination compound with five or six-membered ring, since its-CO-NH-OH group has N, O atoms with lone pair electrons. As its diverse coordination pattern, hydroximic acid complexes can be nononuclear, dinuclear, polynuclear. Hydroximic acid complex has special properties in magnetism, biological activity and host-guest recognition, therefore, it has potential application value in magnetic materials, anti-cancer agent and molecular recognition reagent. Current studies of hydroximic acid complexes are mainly complexes of salicylhydroxamic acid and picolin salicylic acid, while study in complexes of hydroximic acid with parazole and triazole is little. Likewise, pyrazole and triazole as common heterocyclic N donor ligands are effective bridging organic building block for coordination compounds with the ability to act as hydrogen bond donor and/or acceptor. Therefore,we select 1H-pyrazole-3,5-dihydroxamic acid, 1H-4-pyrazolehydroxamic acid and 1H-1,2,4-trizole-3-hydroxamic acid as the ligands, and successfully obtained a series of complexes through the reaction of these ligands with different transition and rare earth metal salts in different conditions. Their structures have been characterized by elemetal analysis, IR and X-ray single crystal diffraction. Magnetism, biological activity and fluorescence property have been determined for some complexes.1. 1H-pyrazole-3,5-dihydroxamic acid(H2dhp) is synthesized and thirteen complexes have been synthesized by the reactions of this ligand with different metal salts: [Zn(Hdhp)2(H2O)2]·2H2O(1), [Ni3(dcp)2(H2O)10]·10H2O(2), Cu3(dcp)2(H2O)6·2H2O(3), [Cu(dcp)]n(4), [Cu(dcp)(DMF)2(H2O)]n(5), [Co(dcp)(H2O)4]·2DMF(6), [Mn4(dcp)2(H2O)8](Hdcp)·3H2O(7), [Zn(Hdcp)(H2O)]n(8), [Pr(dcp)3(H2O)]n(9), [Nd(dcp)3(H2O)]n(10), [Sm(dcp)3(H2O)]n(11),(H3dcp = 1H-pyrazole-3,5-dicarboxylic acid). Complexes 1 is zinic complex. Complexs 2-11 are complexes of 1H-pyrazole-3,5-dicarboxylic acid, which is hydrolyzate of 1H-pyrazole-3,5-dihydroxamic acid. The complexes 1, 3, 6 zero-dimensional structures and they assemble themselves into a two-dimensional network structure via O-H···O and N-H···O interactions. Complexe 3 is a one-dimensional chain structure and its chain structures are connected into a two-dimensional network structure through O-H···O interaction. Complexe 7 is a two-dimensional network structure and its network structures are connected into a three-dimensional supramolecular structure through O-H···O interaction. Complexes 4, 5, 8, 9, 10, 11 are three-dimensional supramolecular structures. Magnetic measurements of complex 2, 4, 6, 10, 11 have been taken and indicates antiferromagnetic coupling between the Ni(II) ions in the complex 2.2. 1H-4-pyrazolehydroxamic acid(H3pza) is synthesized and three complexes have been synthesized by the reactions of this ligand with different metal salts: H3pza(12), [Zn3(H2pza)2(NO3)4(DMF)6](13), [Me2Sn(H2pza)Cl]·H2O(14),(NH4)[Cu3(pze)3Cl3(OH)(H2O)]·2H2O(15)(Hpze = methyl 1H-pyrazole-4-carboxylate), which have been characterized by single-crystal X-ray diffraction, elemetal analysis and IR spectra. Complexe 14 is a 9-MC-3 metallacrown, in which each Cu2+ ions is in a distorted square-pyramid coordination environment and the repeating unit is Cu–N–N.3. 1H-1,2,4-trizole-3-hydroxamic acid(H3tzha) is synthesized and four complexes have been synthesized by the reactions of this ligand with different metal salts: [Co2(H2tzha)2(DMF)6](NO3)2(16), [Zn2(H2tzha)2(DMF)6](NO3)2(17), Co5(H2tzha)2Cl8(DMF)7(18). All of these thress compleses are easily deliquesces in the air.