CO2 chemistry has drawn considerable attention as abundant, low cost, and renewable carbon source in the past decades. The natural stability of CO2 made its utilization a daunting challenge under mild conditions. Recently, there has been significant progress of CO2 fixation by using cheap and abundant functionalized polyoxometalate (POM) catalysts. In this review, the POM catalytic system for transformation of CO2 into valuable compounds such as urea, cyclic carbonate, quinazoline-2,4(1H,3H)-diones, α-methylene cyclic carbonate, oxazolidinones etc. were discussed. The future of POM catalysis for sustainable chemistry lies in the synthesis of highly functionalized task-specific POM catalysts, and rational design of novel reactions which would eventually pave the pathway for the establishment of green, effective, inexpensive and sustainable technologies.

Recent applications of polyoxometalates in CO2 capture and transformation

Carbon dioxide (CO2) and sulfides in gasoline are the main causes of air pollution. Considerable attention has been devoted to solving the problems, and the catalytic reaction seems to be a good ch...

Lewis Acid Dominant Windmill-Shaped V8 Clusters: A Bifunctional Heterogeneous Catalyst for CO2 Cycloaddition and Oxidation of Sulfides.

The combination of polyoxoniobates (PONbs) with 3d metal ions, azoles, and organoamines is a general synthetic procedure for making unprecedented PONb metal complex cage materials, including discrete molecular cages and extended cage frameworks. By this method, the first two PONb metal complex cages K4 @{[Cu29 (OH)7 (H2 O)2 (en)8 (trz)21 ][Nb24 O67 (OH)2 (H2 O)3 ]4 } and [Cu(en)2 ]@{[Cu2 (en)2 (trz)2 ]6 (Nb68 O188 )} have been made. The former exhibits a huge tetrahedral cage with more than 120 metal centers, which is the largest inorganic-organic hybrid PONb known to date. The later shows a large cubic cage, which can act as building blocks for cage-based extended assembly to form a 3D cage framework {[Cu(en)2 ]@{[Cu2 (trz)2 (en)2 ]6 [H10 Nb68 O188 ]}}. These materials exhibit visible-light-driven photocatalytic H2 evolution activity and high vapor adsorption capacity. The results hold promise for developing both novel cage materials and largely unexplored inorganic-organic hybrid PONb chemistry.

Inorganic–Organic Hybrid Polyoxoniobates: Polyoxoniobate Metal Complex Cage and Cage Framework

An efficient methodology for the synthesis of cyclic carbonates from epoxides and CO2 has been developed using self-assembled, ultra small, porous zinc stannate nanocrystals as a catalyst under atmospheric pressure. The catalyst is synthesized by using sodium salicylate as a soft template and the material is thoroughly characterized by powder XRD, HR TEM, N2-sorption and UV-visible spectroscopic tools. Moreover, the catalyst smoothly catalyzes a wide range of reactants to produce a series of cyclic carbonates in excellent yields, under atmospheric pressure of CO2 and in the presence of PEG-600 as a green solvent. The catalyst can be easily recovered from the reaction medium and be reused without significant loss in its catalytic activity and selectivity, suggesting the future potential of this nanocatalyst in the clean-up of the environment.

CO2 fixation at atmospheric pressure: porous ZnSnO3 nanocrystals as a highly efficient catalyst for the synthesis of cyclic carbonates

A series of DyxEr(1–x)-polyoxometalates (POMs) were successfully synthesized and characterized well by various physicochemical analysis. The structurally isolated compounds exhibit three characteristic emissions at 480 nm (blue, 4F9/2 → 6H15/2 transition), 573 nm (yellow, 4F9/2 → 6H13/2 transition), and 663 nm (red, 4F9/2 → 6H11/2 transition) whose luminescent color coordinates appear in the near-white area in the CIE 1931 chromaticity diagram. Time-resolved emission spectroscopy was used in DyxEr(1–x)-POM to further authenticate energy transfer from the photoexcitation O → M ligand to the metal charge-transfer state of phosphotungstate components to active Dy3+/Er3+ ions and energy transfer between Dy3+ ion and Er3+ ion via intramolecular energy transitions. The relative emission intensity of ∼32%, ∼53%, and ∼85% for Dy-POM, Dy0.9Er0.1-POM, and Dy0.8Er0.2-POM respectively, were obtained under 300 min of UV irradiation, which indicates better photostability of Dy0.8Er0.2-POM. Furthermore, DyxEr(1–x)-POM s...

Enhanced Photostability Luminescent Properties of Er3+-Doped Near-White-Emitting DyxEr(1–x)-POM Derivatives

A luminescent polyoxoniobate lanthanide derivative {Eu3(H2O)9[Nb48O138(H2O)6]}27- .

A multi-component polyoxometalate based on earth-abundant elements (NH4)10[Co8(H2O)10V10Mo23O104(OH)6]·34.5H2O (1) has been successfully obtained and characterized. Furthermore, compound 1 acted as a Lewis acid catalyst and promoted the conversion of carbon dioxide to a cyclic carbonate under mild reaction conditions.

A multi-component polyoxometalate and its catalytic performance for CO2 cycloaddition reactions.

Two isomorphic compounds {[Ln2(H2O)10](Mo8O27)}·8H2O (Ln = Tm (1), Er (2)) were obtained by microwave irradiation, in which β-{Mo8O28} building units are linked via bridge oxygen and lanthanide ions coordinated with {MoO6} octahedra. The synthesis chemical processes have a short reaction time (15 min) with high yields (exceeding 85%). The solid-state photochromic properties of these two compounds were studied, and their color change process and the photochromic mechanism were analyzed. Furthermore, the solid-state photoluminescence properties of these two compounds were investigated and the stability of the luminescence was verified. Finally, variable temperature magnetic susceptibilities indicate that both compounds have anti-ferromagnetic interaction properties and 1/χM values are linear with temperature.

Ln(III)-Containing polyoxomolybdates based on β-{Mo8O28}: microwave synthesis and optical and magnetic properties

A three-dimensional (3D) Silverton-type polyoxomolybdate (POMo) with the formula of NH4{Mn4[PrMo12O42]}·18H2O (1) was successfully isolated and well characterized by single crystal X-ray diffraction, X-ray powder diffraction pattern, infrared spectrum, thermogravimetric and elemental analyses. The inorganic building block {PrMo12O42} has formed 3D frameworks via the {MnO6} linker. The excitation of compound 1 in solid state at 375 nm displays red emission. Moreover, variable temperature magnetic susceptibility measurements indicate that the magnetic behavior in compound 1 is dominated by antiferromagnetic interactions.

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A 3D Silverton-Type Polyoxomolybdate Based on {PrMo12O42}: Synthesis, Structure, Photoluminescence and Magnetic Properties.

The photoluminescence study of an organic-inorganic hybrid Keggin-type polyoxotungstate: a better excitation efficiency between polyoxometalate and thulium

Shumin Chen

Papers

A luminescent polyoxoniobate lanthanide derivative {Eu3(H2O)9[Nb48O138(H2O)6]}27- .

A multi-component polyoxometalate and its catalytic performance for CO2 cycloaddition reactions.

Ln(III)-Containing polyoxomolybdates based on β-{Mo8O28}: microwave synthesis and optical and magnetic properties

A 3D Silverton-Type Polyoxomolybdate Based on {PrMo12O42}: Synthesis, Structure, Photoluminescence and Magnetic Properties.

The photoluminescence study of an organic-inorganic hybrid Keggin-type polyoxotungstate: a better excitation efficiency between polyoxometalate and thulium