Synthese, Structures And Properties Study Of Novel Coordination Polymers Base On Polyoxometalate And N-Heterocyclic Derivatives

The aim of this thesis is to synthesize novel metal-organic coordination polymers based on polyoxometalate building blocks by using polyoxometalates (POMs), diverse N-heterocyclic derivatives and transition metal salts, to study the synthetic conditions and rules for these compounds, to analysis the relationship between structures and properties, so as to provide theoretical and experimental foundation for the synthesis of the aim metal-organic coordination polymers which is based on polyoxometalate building blocks.Eight new metal-organic coordination polymers based on polyoxometalate building blocks and one novel capped polyoxometalate have been synthesized on the basis of hydrothermal or solvothermal technique. In addtion, their structures were characterized by elemental analyses, ICP analyses, IR spectra, single-crystal X-ray diffraction analyses and X-ray powder diffraction (XRPD), while their thermal stabilities (TG) properties have also been studied.1. Three new 3D polyoxometalate-based microporous metal-organic frameworks with helical features have been solvothermally synthesized by self-assembly of hexaammonium molybdate and transition metal salts in the presence of triangular N-containing carboxylate ligand, that are, [Co4(tpba)6(H2O)3][SMo12O40]·10H2O (1)[(CH3)2NH2][{Co(tpba)}{Mo2O7}]·2H2O (2)[(CH3)2NH2][{Ni(tpba)}{Mo2O7}]·2H2O (3)Compound 1 is a novel metal-organic framework using Keggin POMs as template and containing nanotubes based on twelve-fold interwoven helices, and now represents the highest-numbered association of helical chains in the field of polyoxometalate-based coordination polymers. Compounds 2 and 3 are closed to be isostructural and both of them are pillared architectures with 2-fold interpenetrated network with chiral features. Microporous structure is the common character of those products, and therefore, they may have potential applications in the aspect of gas adsorption.2. One new capped polyoxometalate has been solvothermally synthesized, that is, [(CH3)2NH2]4(H3O)3[Cu{Mo16O52}]·4.5H2O (4)Compound 4 is a tetra-capped Keggin structure, and its biggest characteristic is introducing Cu(I) into the central place of the capped polyoxometalate. Compound 4 represents the first capped polyoxometalate which is using Cu(I) as hetero atom.3. Two new 1D helical metal-organic frameworks based on polyoxometalate have been hydrothermally synthesized by self-assembly of Keggin POMs and copper salts in the presence of triangular N-heterocyclic derivatives or long-chain N-containing carboxylate ligand, that are, (H3O)[{Cu(H2tpim)2}{SiMo12O40}]·0.5H2O (5) [Cu2(Hcpp)3(cpp)(H2O)][PMo12O40]·2H2O (6)Compounds 5 and 6 exhibit (1Dâ†'2D) interdigitated architectures assembled from 1D helical chains. Compound 5 is constructed by the achiral 2D layers which are assembled from some opposite-handed helical chains interdigitated with each other. Adjacent 2D layers are further connected by hydrogen bonding involving N-containing ligand and POMs into an intriguing 3D supramolecule network. Compound 6 is constructed by the chiral 2D layers which are assembled from some same-handed helical chains interdigitated with each other. Adjacent 2D layers with opposite-handed are further extented by supramolecule interactions into a 3D supramolecule network, in which POMs act as template. In addition, the thermal stabilities (TG) of compounds 5 and 6 have also been studied.4. Three novel 1D inorganic-organic hybrid compounds based on polyoxometalate have been hydrothermally synthesized by self-assembly of transition vanadate or phosphomolybdate and metal salts in the presence of H2api ligand, that are, [Ni(H3api)4][V16O38Cl]·10H2O (7) [Co(H3api)4][V16O38Cl]·10H2O (8) (H3api)2(H3O)2[Cu{P2Mo5O23}(H2O)2] (9)Compounds 7 and 8 are isostructural and consist of two kinds of ID chains spanning two different directions, while compound 9 only consists of one kind of 1D chains extending one direction. Finally, all of the products display a 3D supramolecule network with ABAB stack. What is worth our attention is that both compound 7 and compound 8 are constructed on the base of novel {Vi6} cluster. Additionally, the thermal stabilities (TG) of compound 9 have also been studied.