Polyoxometalates (POMs) are discrete anionic metaloxygen clusters which can be regarded as soluble oxide fragments. They exhibit a great diversity of sizes, nuclearities, and shapes. They are built from the connection of {MOx} polyhedra, M being a d-block element in high oxidation state, usually VIV,V, MoVI, or WVI.1 While these species have been known for almost two centuries, they still attract much interest partly based on their large domains of applications. They play a great role in various areas ranging from catalysis,2 medicine,3 electrochemistry,4 photochromism,5 to magnetism.6 This palette of applications is intrinsically due to the combination of their added value properties (redox properties, large sizes, high negative charges, nucleophilicity...). Parallel to this domain, the organic-inorganic hybrids area has followed a similar expansion during the last 10 years. The concept of organic-inorganic hybrid materials * To whom correspondence should be addressed. E-mail: dolbecq@ chimie.uvsq.fr. Chem. Rev. 2010, 110, 6009–6048 6009

Hybrid Organic−Inorganic Polyoxometalate Compounds: From Structural Diversity to Applications

Recent Developments in the Preparation and Chemistry of Metallacycles and Metallacages via Coordination

Efficient removal of organic pollutants from wastewater has become a hot research topic due to its ecological and environmental importance. Traditional water treatment methods such as adsorption, coagulation, and membrane separation suffer from high operating costs, and even generate secondary pollutants. Photocatalysis on semiconductor catalysts (TiO2, ZnO, Fe2O3, CdS, GaP, and ZnS) has demonstrated efficiency in degrading a wide range of organic pollutants into biodegradable or less toxic organic compounds, as well as inorganic CO2, H2O, NO3−, PO43−, and halide ions. However, the difficult post-separation, easy agglomeration, and low solar energy conversion efficiency of these inorganic catalysts limit their large scale applications. Exploitation of new catalysts has been attracting great attention in the related research communities. In the past two decades, a class of newly-developed inorganic–organic hybrid porous materials, namely metal–organic frameworks (MOFs) has generated rapid development due to their versatile applications such as in catalysis and separation. Recent research has showed that these materials, acting as catalysts, are quite effective in the photocatalytic degradation of organic pollutants. This review highlights research progress in the application of MOFs in this area. The reported examples are collected and analyzed; and the reaction mechanism, the influence of various factors on the catalytic performance, the involved challenges, and the prospect are discussed and estimated. It is clear that MOFs have a bright future in photocatalysis for pollutant degradation.

Photocatalytic organic pollutants degradation in metal–organic frameworks

2.4.2. Interpenetrated Ladders 711 2.4.3. Unusual Motifs of Ladders 713 2.4.4. Properties of Ladderlike Chains 713 2.5. Rotaxane Polymers 714 2.5.1. 1D Polyrotaxanes 714 2.5.2. 2D Polyrotaxanes 715 2.5.3. 3D Polyrotaxanes 716 2.5.4. Hydrogen-Bonded Polyrotaxanes 716 2.6. Ribbon/Tape Polymers 717 2.7. Metal Cluster As Building Blocks for 1D CP 718 2.7.1. Metal Carboxylate Clusters 718 2.7.2. Metal Halide Clusters 719 2.7.3. Metal Chalcogenide Clusters 720 2.7.4. Polyoxometalate Clusters 721 2.7.5. Single Molecular Magnets as Building Blocks 722

One-Dimensional Coordination Polymers: Complexity and Diversity in Structures, Properties, and Applications

Functionalization of polyoxometalates: towards advanced applications in catalysis and materials science

An organic-inorganic hybrid Dy(III)-containing polyoxomolybdate based on functionalized diphosphonate ligands

Syntheses and structure of three 2D polyoxometalates derived from macrocation [Cr3O(COOH)6(H2O)3]+ and α-Keggin-type polyoxomolybdate anions

A new organic–inorganic composite (4,4′-H2bipy)2(4,4′-Hbipy)2(ZnW12O40)·6H2O has been prepared by hydrothermal reaction and characterized by elemental analysis, IR and UV spectra, thermal analysis and single-crystal X-ray structural analysis. It belongs to the monoclinic system, space group P21/c, with a = 18.637(4), b = 14.003(3), c = 26.470(5) A, β = 104.78(3)°, V = 6680(2) A3, Z = 4. Structural analysis indicates that the title complex consists of a Keggin anion [ZnW12O40]6−, 4,4′-bipyridine and water of crystallization, constructing a supramolecular system through hydrogen bonding interactions. Thermal analysis shows that the heteropolyanion [ZnW12O40]6− starts to decompose at 587.0°C.

Hydrothermal synthesis and structure characterization of a new organic–inorganic composite (4,4′-H2bipy)2(4,4′-hbipy)2(ZnW12O40)·6H2O

Synthesis, characterization and crystal structure of a new β-octamolybdate-supported compound: [Ni(H2O)(2, 2′- bipy)2]2[Mo8O26] · 4H2O · 2CH3COOH

A new polyoxometalate based on saturated Wells-Dawson polyanions and calcium cations, H2[Ca2(P2W18O62)(H2O)5] · 7.5H2O (1), has been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction and IR. Compound 1 is a new example of 3D framework based on Wells-Dawson anions that act as chelate ligands to coordinate with calcium cations. Cyclic voltammetry reveals that the pH of the supporting electrolytic solution has a marked effect on the electrochemical behavior.

Jingping Wang

Papers

An organic-inorganic hybrid Dy(III)-containing polyoxomolybdate based on functionalized diphosphonate ligands

Syntheses and structure of three 2D polyoxometalates derived from macrocation [Cr3O(COOH)6(H2O)3]+ and α-Keggin-type polyoxomolybdate anions

Hydrothermal synthesis and structure characterization of a new organic–inorganic composite (4,4′-H2bipy)2(4,4′-hbipy)2(ZnW12O40)·6H2O

Synthesis, characterization and crystal structure of a new β-octamolybdate-supported compound: [Ni(H2O)(2, 2′- bipy)2]2[Mo8O26] · 4H2O · 2CH3COOH

A new 3D polyoxometalate based on saturated Wells–Dawson polyanions and calcium cations