Heteropolyacid-Based Materials as Heterogeneous Photocatalysts

Single-Molecule Magnet Behavior of Individual Polyoxometalate Molecules Incorporated within Biopolymer or Metal-Organic Framework Matrices

The chemically and structurally highly stable polyoxometalate (POM) single-molecule magnet (SMM) [(FeW9 O34 )2 Fe4 (H2 O)2 ](10-) (Fe6 W18 ) has been incorporated by direct or post-synthetic approaches into a biopolymer gelatin (Gel) matrix and two crystalline metal-organic frameworks (MOFs), including one diamagnetic (UiO-67) and one magnetic (MIL-101(Cr)). Integrity of the POM in the Fe6 W18 @Gel, Fe6 W18 @UiO-67 and Fe6 W18 @MIL-101(Cr) composites was confirmed by a set of complementary techniques. Magnetic studies indicate that the POMs are magnetically well isolated. Remarkably, in Fe6 W18 @Gel, the SMM properties of the embedded molecules are close to those of the crystals, with clear quantum tunneling steps in the hysteresis loops. For the Fe6 W18 @UiO-67 composite, the molecules retain their SMM properties, the energy barrier being slightly reduced in comparison to the crystalline material and the molecules exhibiting a tunneling rate of magnetization significantly faster than for Fe6 W18 @Gel. When Fe6 W18 is introduced into MIL-101(Cr), the width of the hysteresis loops is drastically reduced and the quantum tunneling steps are smeared out because of the magnetic interactions between the antiferromagnetic matrix and the SMM guest molecules.

An organo-functionalized metal–oxide cluster, [VIV6O6{(OCH2CH2)2N(CH2CH2OH)}6], with Anderson-like structure

The polyoxovanadium cluster compound, [VIV6O₆{(OCH₂CH₂)₂N(CH₂CH₂OH)}₆], is the isopolyoxovanadium analogue to cationic heteropolyoxovanadium species, such as [MVIV6O₆{(OCH₂CH₂)₂N(CH₂CH₂OH)}₆]⁺ (M = Li, Na). These isopolyoxovanadium and heteropolyoxovanadium clusters represent the first reported isopoly-heteropoly analogues in the polyoxometalate field.

The first 3D host–guest structure based on a three-fold interpenetrated Ag-pz coordination polymer network and Keggin-type aluminum tungstates with photo/electro-catalytic properties

A 3-D POMOF host–guest structure based on {AlW₁₂} and Ag-pz MOF units was prepared, which exhibit good photo- and electrocatalytic behavior.

Inorganic materials acting as heterogeneous photocatalysts and catalysts in the same reactions

General considerations on the differences and similarities between heterogeneous photocatalysis and thermal catalysis are presented.

Heterogenization of heteropoly compounds: a review of their structure and synthesis

The heterogenization of different types of heteropoly compoundsviasix popular methods from those published over the past recent 15 years is reviewed.

Novel rare earth tungstoarsenate heteropolyoxometalates K11[Ln(AsW 11O 39) 2]·xH 2O (Ln = La, Nd, Sm) binding to bovine serum albumin: spectroscopic approach

The rare earth salts of heteropoly have been widely applied in many fields. In this study, the biological activity of rare earth tungstoarsenate heteropolyoxometalates K11[Ln(AsW11O39)2]·xH2O (abbr. LnW11, Ln = La (x = 24), Nd (x = 17), and Sm (x = 19)) were investigated by spectroscopic methods including fluorescence spectroscopy and UV-vis absorption spectroscopy at different temperatures. In the mechanism discussion, it was proved that the fluorescence quenching of bovine serum albumin (BSA) by LnW11 is initiated by complex formation. The thermodynamic parameters suggested that the binding of LnW11 to BSA is spontaneous, and the mainly force is electrostatic interactions. Site marker competitive experiments demonstrated that LaW11 binds with high affinity to site I (subdomain IIA) of BSA; but SmW11 and NdW11 bind with affinity to both site I (subdomain IIA) and site II (subdomain IIIA) of BSA. The results of synchronous fluorescence spectrum indicate that the secondary structure of BSA molecules was changed in the presence of LnW11. In addition, the binding parameters, binding site number, and effect of metal ions on LnW11-BSA were also discussed.

Anchoring H3PW12O40 on 3-aminopropyltriethoxysilane modified graphene oxide: enhanced adsorption capacity and photocatalytic activity toward methyl orange

A novel PW₁₂/GO–NH₂ hybrid was obtained via an impregnation method, which exhibited enhanced adsorption capacity and photocatalytic activity.

Synthesis, crystal structure and properties of sandwich type compounds based on {AsW9} and a hexa-nuclear unit with three supporting TM–triazole complexes

Tree {AsW₉}-based sandwich compounds exhibit good electrocatalytic activity, antiferromagnetic interactions, and inhibitory effect on proliferation of HeLa cells.

A radiation sensitive hybrid polymer based on an Mn-Anderson polyoxometalate cluster and a UV active organic monomer: synergistic effects lead to improved photocurrent in a photoresponse device

A new radiation sensitive polyoxometalate/polymer hybrid has been developed which shows good photocurrent generation in a photoresponse device.

Assembly of a basket-like {Sr ⊂ P6Mo18O73} cage from 0D dimmer to 2D network and its photo-/electro-catalytic properties

Five semiconductor materials based on basket-like POM have been hydrothermally synthesized, which show high-efficient degradation ability for organic dyes RhB, MB, and AP in short time and bifunctional electrocatalytic behavior for oxidation of AA and reduction of NO₂⁻.

High-efficiency photo- and electro-catalytic material based on a basket-like {Sr⊂P6Mo18O73} cage

The first 8-connected 2D layer based on basket-liked {Sr⊂P₆Mo₁₈O₇₃} cage was prepared, which exhibits high-efficient photodegradation ability for MB, RhB, and AP under visible and UV light, as well as bifunctional electrocatalytic behavior.

Photocatalytic conversion of glucose in aqueous suspensions of heteropolyacid–TiO2 composites

Commercial and home prepared TiO₂ samples were functionalized with a commercial Keggin heteropolyacid (HPA) H₃PW₁₂O₄₀ (PW₁₂) or with a hydrothermally home prepared K₇PW₁₁O₃₉ salt (PW₁₁).

Organo-functionalized metal–oxide clusters: synthesis and characterization of the reduced cationic species [NaVIV6O6{(OCH2CH2)2NH}6]+

A new diethanolamine functionalized oxovanadium cationic cluster was synthesized and characterized; electrochemical and UV-vis absorption properties are consistent with two distinct MLCT processes.