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

A novel 24-niobic-2-tellurite, [H2Te2Nb24O72]14–, was isolated by incorporating tellurite anions into a polyoxoniobate cage. The synthesized cluster represents the first example of a sandwich-type polyoxoniobate with the largest telluroniobate aggregate. Furthermore, the hybrid material acts as an efficient catalyst for the decolorization of basic fuchsin.

Assembly of TeO32- Ions Embedded in an Nb/O Cage with Selective Decolorization of Organic Dye.

A novel germanotungstate derivative based on the dysprosium cation and monovacant Keggin anion, [Cu(en)2]2[Cu(en)2(H2O)]2H3{[Cu(en)2]2[Na2(H2O)1.75][K(H2O)3][Dy2(H2O)2(GeW11O39)3]} · 6H2O(en = ethylenediamine) 1, has been synthesized by hydrothermal method and characterized by elemental analysis, IR-UV spectroscopy, thermal analysis and single-crystal X-ray diffraction. In the compound, one kind of clusters with the Dy3+/[GeW11O39]8− ratio of 2:3 was observed. Especially, the 2:3 type displays the novel cluster based on the rare earth and monolacunary Keggin polyoxometalate.

Hydrothermal Synthesis and Crystal Structure of One Rare Earth Substituted Keggin-Type Germanotungstate [Cu(en)2]2[Cu(en)2(H2O)]2H3{[Cu(en)2]2[Na2(H2O)1.75][K(H2O)3][Dy2(H2O)2 (GeW11O39)3]} · 6H2O

Design and synthesis of high-performance heterogeneous catalysts are of immense interest in chemical industries. Herein, ultrafine H2O coordinated WOx nanoparticles (H2O–WOx, average diameter 2.24 ...

Efficient Olefins Epoxidation on Ultrafine H 2 O–WO x Nanoparticles with SpectroscopicEvidence of Intermediate Species

The first polyoxometalate based on Keggin dodecatungstoselenate framework supported copper(I) coordination group: [Cu2(2,2′-bpy)4Cl][Cu(2,2′-bpy)2SeW12O40] · 2H2O

A novel polyoxometalate cluster, i.e., Na1.5H4.5[(CH3)4N]2{[Mn(CO)3]4(Se2W11O43)}·9H2O (1), has been successfully synthesized under moderately acidic conditions. Compound 1 contains four electron-donating {Mn(CO)3}+ organometallic entities, which are grafted over an unprecedented heteropolytungstate electron-acceptor group. Compound 1 was further structurally characterized by various physicochemical techniques like elemental analyses, inductively coupled plasma (ICP) analyses, IR and UV–vis spectroscopy, electrochemistry, and single-crystal X-ray diffraction, and so on. The polyoxoanion of 1 comprises a novel {Se2W11} fragment, which is obtained from molecular assembly of rare {SeW3} and {SeW8} species. Evaluation of the data from solution-state IR spectrum showed excellent agreement with the solid state IR spectrum, indicating the intact clusters in the CH3CN/Na2SO4 solvent. Also, negative electrospray ionization mass spectrometry (ESI-MS) was an alternative tool to verify the stability of 1 in the mixed...

Jingping Wang

Papers

Assembly of TeO32- Ions Embedded in an Nb/O Cage with Selective Decolorization of Organic Dye.

Hydrothermal Synthesis and Crystal Structure of One Rare Earth Substituted Keggin-Type Germanotungstate [Cu(en)2]2[Cu(en)2(H2O)]2H3{[Cu(en)2]2[Na2(H2O)1.75][K(H2O)3][Dy2(H2O)2 (GeW11O39)3]} · 6H2O

Efficient Olefins Epoxidation on Ultrafine H 2 O–WO x Nanoparticles with SpectroscopicEvidence of Intermediate Species

The first polyoxometalate based on Keggin dodecatungstoselenate framework supported copper(I) coordination group: [Cu2(2,2′-bpy)4Cl][Cu(2,2′-bpy)2SeW12O40] · 2H2O

Facile CO2 Cycloaddition to Epoxides by Using a Tetracarbonyl Metal Selenotungstate Derivate [{Mn(CO)3}4(Se2W11O43)]8–