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Hydrothermal Synthesis And Characterization Of Polyoxomolybdate, Molybdenum Phosphate And Coordination Polymer

Posted on:2007-08-28Degree:DoctorType:Dissertation
Country:ChinaCandidate:X HeFull Text:PDF
GTID:1101360185955276Subject:Inorganic Chemistry
Abstract/Summary:PDF Full Text Request
Metal-oxygen cluster has important application in acid or redox catalysis and otherarea for its novel structures and electronic characters. Coordination polymers asfunctional solid materials with specific network topologies are of great interest due totheir fascinating molecular structures and potential applications to magnetism,nonlinear optical materials, electrical conductivity, ion exchange, separation, biology,and catalysis. So the goal of this work is to synthesis and preparation ofpolyoxomolybdate, molybdenum phosphate with organism and coordinationpolymers with 3,5-dinitrosalicylic acid ligand continuously and systematically byhydrothermal routes.The synthesis of inorganic-organic hybrid material by incorporation of chiral metalcomplex is a novel effective method. To get crystals with chiral characters, in thesystem of organic amine, transition metals and molybdenum phosphate, we tookchiral metal complex [Co(en)3]Cl3 or piperazine as template and obtained fivemolybdenum phosphate 1 -5 and two condense phosphate 6, 7. Cyclicvoltammograms (100 mV/s) in hydrochloric acid solutions of 2 and 3 have beenstudied and it showed that the two couples of peaks correspond to three-electronredox processes. The study of variation of the molar magnetic susceptibility of 3indicates that there is weak ferromagnetic behavior and some orbital contribution in3. We also study the impact of reaction pH to production. It indicated that pH is a keyrole in the reaction system. Nowadays, compared with the study of polyoxomolybdate with organic aminesynthesis, the study of polyoxomolybdate with organic acid synthesis is much less,so the study of polyoxomolybdate with organic acid synthesis is a new area. In orderto syntheses the polyoxomolybdate with organic acid, in the system of organic acid,organic amine, transition metals and polyoxomolybdate, we took nicotinic acid andimidazole as ligand and synthesized a nicotinic acid-coordinated polyoxomolybdate8 and four polyoxomolybdate with organic amine 9-12. 8 is the first 3Dpolyoxomolybdates supramolecular architecture with nicotinic acid ligands. Thestudy of 9-12 indicate that it is easy to get polyoxomolybdate with organic amine atweak acidity conditions when there are organic amine and organic acid in the samereaction systems.Helical structures in supramolecular chemistry and materials science havepotential applications in the field of asymmetric catalysis, nonlinear optical materialsand the aesthetically appealing topologies of crystal engineering. So the synthesis ofhelical inorganic-organic hybrid material has great impotance. Design of flexibleasymmetric bridging ligands to form helical inorganic-organic hybrid material is aneffective method. 3,5-dinitrosalicylic acid, as an asymmetric bridging ligand, hasgood coordination ability. In order to syntheses helical coordination polymers, in thesystem of 3,5-dinitrosalicylic acid, 1,10-phenanthroline and metals, we took Co, Zn,Mn, La to synthese three 1D and one cluster complexes 13-16. 13 exhibits a rarestructure of a meso-helix which is a 3D presentation of a lemniscate. 14 and 15 areisomorphic one-dimensional helical structures. 16 is a tetranuclear lanthanumcomplex. The study of variation of the molar magnetic susceptibility of 13 and 15indicates that there is weak antiferromagnetic behavior and little orbital contributionin 13 and 15. The emission spectra of 14 exhibits intense blue photoluminescenceand 14 may be used as a good candidate of emission material for its high thermalstability. The success of synthesis of 13 -15 indicates that incorporation ofasymmetric bridging ligands is an effective way to obtain helical coordinationpolymers.
Keywords/Search Tags:Polyoxomolybdate,
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