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The Study Of The Functionalized Inorganic-Organic Hybrid Compounds Based On Keggin-type And Anderson-type Polyoxometalates

Posted on:2008-09-07Degree:DoctorType:Dissertation
Country:ChinaCandidate:H Y AnFull Text:PDF
GTID:1101360215979051Subject:Inorganic Chemistry
Abstract/Summary:PDF Full Text Request
Chiral polyoxometalates (POMs) attract considerable attention, because of their extensive applications in enantioselective catalysis, separation and pharmacy. In this thesis, we study the construction of chiral polyoxometalates, polyoxometalates with chiral characterization and nonchiral high-dimensional inorganic-organic hybrid compounds, based on Keggin and Anderson-type polyoxoanion clusters, which are obtained by chiral, asymmetric and nonchiral organic ligands as organic components. The study on synthetic conditions and rules for these new compounds and the exploration of relationships between structures and properties for these new compounds are also carried out.Twenty new hybrid compounds based on polyoxometalate building blocks have been synthesized via water solution synthesis methods, and structurally characterized by elemental analyses, IR, XPS, ESR and single crystal X-ray diffractions. The thermal stabilities, circular dichroism spectroscopy (CD) and magnetic properties of these compounds have been studied.1. Two unprecedented enantiomerically pure 3D polyoxometalate hybrid species on the basis of Keggin type polyoxoanion clusters and Cu-proline complex units have been synthesized for the first time. Compounds 1 and 2 are a pair of enantiomer, representing the first three-dimensional chiral polyoxometalates in the world. Both three-dimensional chiral compounds have intriguing chiral channels, which are built up of homochiral intertwined double helices. The circular dichroism spectra of 1 and 2 in water have shown they are stable in solution, which document they will be significantly useful in asymmetric catalysis and chiral medicine. In addition, a nonchiral 3D framework was obtained, which is built up of Keggin building blocks and hexanuclear Cu-glycine coordination clusters, exhibiting interesting ferromagnetic interactions: KH2[(D-C5H8NO2)4(H2O)Cu3][BW12O40]·5H2O) (1) KH2[(L-C5H8NO2)4(H2O)Cu3][BW12O40]·5H2O (2) H4[(H2O)2Na][Na(H2O)2(gly)8Cu6][BW12O40]2·13H2O (3)2. Four 2D chiral layer compounds, two 3D open-framework polar compounds and six high-dimensional hybrid complexes have been gained, based on Anderson type polyoxoanions as building blocks and rare-earth-organic coordination complexes as functional linkers: (C5H9NO2)2[La(H2O)7CrMo6H6O24]·11H2O (4) (C2H5NO2)2[Nd(H2O)5][CrMo6H6O24]·10H2O (5) (C6H5NO2)[(H2O)4(C6H5NO2)La(CrMo6H6O24)]·4H2O (6) (C6H5NO2)[(H2O)4(C6H5NO2)Ce(CrMo6H6O24)]·4H2O (7) (C6H5NO2)[(H2O)4(C6H5NO2)Pr(CrMo6H6O24)]·4H2O (8) (C6H5NO2)[(H2O)4(C6H5NO2)Nd(CrMo6H6O24)]·4H2O (9) (C6H5NO2)2[(H2O)6DyCrMo6H6O24]·4H2O (10) (C6H5NO2)2[La(H2O)5(CrMo6H6O24)]·0.5H2O (11) (C6H5NO2)2[Ce(H2O)5(CrMo6H6O24)]·0.5H2O (12) [(C6H5NO2)2La(H2O)4]2[IMo6O24][NO3]·4H2O (13) [(C6H5NO2)2Ce(H2O)4]2[IMo6O24][NO3]·4H2O (14) H5[(C6H4NO2)4(H2O)15Nd3][IMo6O24]2·13.5H2O (15)In the presence of chiral L-proline molecule, when La3+ was added to the reaction solution, we attained a nonchiral compound 4. Compound 4 is a lanthanide-polyoxometalate wavelike chain, with racemic proline molecules situated in the framework via hydrogen bonds. Compound 5 displays a three-dimensional supramolecular channel framework built up of B-type Anderson structures and Nd-glycine coordination complexes. When asymmetric pyridine-4-carboxylic acid ligand similar to proline was chose, compounds 6-9 were achieved. They are isostructural and exhibit a new chiral layer built up from B-type Anderson polyoxometalates and rare earth coordination complexes, representing the first chiral layer based on rare earth ions and polyoxometalates. The magnetic properties of 7-9 have been studied, exhibiting the existence of antiferromagnetic interactions in 7-9. Compounds 10 show a novel one-dimensional chain formed by B-type Anderson polyoxoanion and Dy3+, containing pyridine-4-carboxylic acid ligands between neighboring chains. In the presence of pyridine-3-carboxylic acid molecule, two unique three-dimensional open-framework polar compounds 11-12 were obtained composed of B-type Anderson polyoxoanions and rare earth cations with pyridine-3-carboxylic acid molecules in the channels. When A-type Anderson polyoxometalate was utilized instead of B-type Anderson with pyridine-4-carboxylic acid ligand as organic components, three nonchiral compounds were attained. In compounds 13-14, A-type Anderson clusters were connected by rare earth-pyridine-4-carboxylic acid coordination complexes chains to form a two-dimensional sheet. Compound 15 is a dimer formed by A-type Anderson polyoxometalates and trinuclear rare earth complex clusters.3. Four nonchiral high-dimensional hybrid polyoxometalates have been synthesized by virtue of Anderson type polyoxoanions as building blocks and transition metal coordination complexes as bridges. In addition, we achieved an inorganic 3D open framework constructed from Anderson polyoxoanions and Ag+ ions: [(Gly)2Cu][Na(H2O)4Cr(OH)6Mo6O18]·9.5H2O (16) (C6NO2H6)2[(C6NO2H5)2Ag][Cr(OH)6Mo6O18]·4H2O (17) [(H2O)4Ag3][Cr(OH)6Mo6O18]·3H2O (18) [(H2O)5Na2(C6NO2H4)(C6NO2H5)3Ag2][Ag2IMo6O24(H2O)4]·6.25H2O (19) [(H2O)4Na2(C6NO2H5)6Ag3][IMo6O24]·6H2O (20)Compound 16 possesses two-dimensional window-like network constructed from B-type Anderson polyanions bridged by Cu-glycine fragments and Na+ cations in two directions. In compounds 17, B-type Anderson polyoxoanions were linked by Ag-pyridine-4-carboxylic acid complexes to obtain a one-dimensional structure. Compound 19 shows a three-dimensional open framework with one-dimensional channels built from B-type Anderson clusters and silver cations. Compound 19 is built up of a new type of [IMo6O24(H2O)4]5- cluster as the structural motif covalently linked by silver ions to yield unprecedented one-dimensional chains, which further pillar the silver-organic coordination polymer sheets to form a three-dimensional framework, and the free water molecules reside in the frameworks. Compound 20 has a two-dimensional hybrid structure on the basis of A-type Anderson polyoxometalates and trinuclear silver coordination complex subunits and sodium dimmers.
Keywords/Search Tags:Polyoxometalate, Inorganic-Organic Hybrid Compound, Crystal Structure, Chirality
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