A series of diphenyliodonium and tetrabutylammonium salts of vanadium (+V) and iron (+III) mono and disubstituted polyoxotungstates was designed and tested as visible light photoinitiators for the free radical polymerization of acrylates or the cationic polymerization of epoxides. Interestingly, these polyoxotungstates could act as efficient photosensitizers for Type I or Type II photoinitiators (TPO-L, ITX), enabling to get excellent monomer conversions upon excitation at 405 nm.

In the last few years, pharmaceutical compounds classified as emerging pollutants have attracted the attention of many researchers, due to their massive presence in soil, surface, sewage, groundwater and drinking water, as well as to their harmful effects on human health and the environment. In this context, the degradation of four drugs with different chemical structures, Ciprofloxacin, Oxytetracycline, Ibuprofen and Erythromycin was investigated. Indeed, in this paper, we studied the impact of the presence in the aqueous solution of a newly developed POM/polymer composite on the removal of these different drugs from water. Synthesis details and characterizations of these materials have already been reported within our group. The various experiments carried out during this study revealed that the presence of the phosphomolybdic acid-based composite was not essential for the total degradation of Ciprofloxacin and Oxytetracycline which could be totally removed from water by simple photolysis under UV-Visible lamp irradiation. However, under the same experimental conditions, the use of this photocatalyst was indispensable for the total mineralization of Ibuprofen, more recalcitrant than the other selected drugs. In fact, only 20% of this pharmaceutical was degraded by simple photolysis vs. 100% and 94% upon respectively, 90 min of UV-Visible lamp and solar irradiation, in the presence of the phosphomolybdic acid-based composite which was more pertinent than the usually used photocatalyst, namely titanium dioxide. The Ibuprofen degradation pathway was identified thanks to mass spectrometry analysis, conducted at different time intervals. The obtained results demonstrated also that POM/polymer composite inhibits the degradation of Erythromycin through the formation of more toxic intermediates than the original drug.

Hybrid H3PMo12O40/polymer composites were proposed here for the simple photocatalytic decomposition of erythrosine B and rose Bengal because of their unwanted effect on the environmental microorganism. Interestingly, the composite exhibited efficient photocatalytic activity for the decomposition of dyes under both mild near UV irradiation and solar irradiation. High final conversions were obtained for both of dyes reaching 81% and 86% for the erythrosine B and rose Bengal respectively after 120 min of LED@375 nm illumination and 90% for both dyes after only 30 min of solar exposure. The photocatalytic stability was also demonstrated. The photoluminescence technique was used to prove hydroxyl radicals implication into the photo-decomposition reaction using H3PMo12O40/polymer. The efficiency of the proposed treatment was confirmed by the evaluation of the ecotoxicity effect of by-products of each dye on two bacterial strains.

Nowadays water scarcity represents a threat for human and living beings. Therefore, to satisfy the demands of people for clean and safe water, new technologies for wastewater treatment have been developed. Thus, photocatalysis has emerged as a green chemical approach for such treatment. In this context, new polyoxometalate (POM)/polymer composites with relevant photocatalytic properties have been developed via an easy and cheap photopolymerization process upon mild visible light irradiation at 405 nm. This fruitful association between POM and polymer allowed the obtention of shaped materials facile to collect and reuse at the end of the photocatalytic treatment avoiding then the usual time-consuming regeneration methods. The prepared photocomposites displayed excellent photocatalytic performance for the removal of bisphenol-A from water under different sources of irradiation. Hence, 100%, 88%, and 50% of this model compound were decomposed by the phosphomolybdic composite under just 90 min of UV lamp, solar and LED@375 nm irradiations, respectively. The effectiveness of these developed photocatalysts towards the degradation of other organic compounds, as well as the degradation mechanism based on the generation of highly reactive chemicals such as (OH)-O-center dot radicals promoting the degradation were already reported. Bisphenol-A degradation pathway and the identification of the photoproducts were discussed using mass spectroscopy technique. Therefore, this paper highlighted the photocatalytic efficiency of the new manufactured materials for the photodegradation of the bisphenol-A, thus expanding their application fields, under different sources of irradiation and under pure solar irradiation which make their applications more interesting and less energy consuming.

A highly performing proton conducting composite was prepared through the impregnation of EMIMCl ionic liquid in the mesoporous MIL-101(Cr)-SO3H MOF. The resulting EMIMCl@MIL-101(Cr)-SO3H composite displays high thermal and chemical stability, alongside retention of a high amount of EMIMCl even at temperatures as high as 500 K, as well as under moisture conditions. Remarkably, this composite exhibits outstanding proton conductivity not only at the anhydrous state (σ473 K = 1.5 × 10-3 S cm-S) but also under humidity (σ(343 K/60%-80%RH) ≥ 0.10 S cm-1) conditions. This makes EMIMCl@MIL-101(Cr)-SO3H a unique candidate to act as a solid state proton conductor for PEMFC applications under versatile conditions.

: Different inorganic/organic photo-composites based on Polyoxometalate (POM) nanoparticles have been developed for photocatalytic applications. Currently, polyoxometalate nanoparticles have been successfully in-situ embedded into an acrylate polymer network by photopolymerization upon mild visible light irradiation at 405 nm. The proposed POM/polymer photocomposites have been characterized using complementary techniques for a better understanding of their photocatalytic activity. Interestingly, the obtained photocomposites exhibit high rigidity, excellent thermal stability, a non-negligible porosity

ABSTRACTNew polyoxometalate (POM)/polymer hybrid composites were prepared by photopolymerization under mild conditions for suitable photocatalytic processes. Polyoxometalates were incorporated in special photosensitive resins, which were photopolymerized under visible light to obtain new materials with photocatalytic activity for dye removal. The synthesized composites were characterized by real‐time FT‐IR, and the photocatalytic ability was investigated on Eosin‐Y removal using photolysis under near UV irradiation. Interestingly, the polyoxometalates keep their photocatalytic properties, while incorporated into the polymeric matrix since very high conversion rates of Eosin‐Y were achieved. Indeed, degradation efficiencies of about 98% and 93% were registered when using H3PMo12O40/polymer and 94% for SiMo12O40(IPh2)4/polymer composites, respectively. These first results reported in this article show that the new synthesized POM/polymer composites could be considered as promising materials for green and more suitable organic dye removal from aqueous solutions. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1538–1549

New insights about the electrochemical properties of S-containing polyoxometalates. Electrochemical properties of the compounds γ-[SiW10O36(M2O2E2)]6− (M = Mo(v) or W(v); E = O2− or S2−) in DMF.

Seasonal heat storage technologies are the key for a widespread use of solar thermal energy in residential applications. This can be achieved using hygroscopic salts encapsulated in a porous matrix with a high pore volume. Using strontium bromide encapsulated in the mesoporous MIL-101(Cr) Metal-Organic Framework, a heat storage density of 233 kW h/m(3) could be achieved, by using water vapor at a partial pressure as low as 1.25 kPa. This excellent result is partly due to the high salt content (63 wt. %), but also to unexpected modifications of the water sorption isotherms of SrBr2 once it is encapsulated. At a temperature of 30 degrees C, ideal for space heating in low energy dwellings, it may be suggested that the salt is partially soluble upon water sorption.

A drop-casted thin film consisting of a Keggin-type polyoxometalate cluster K3PMo12O40 mixed with the semi-conducting poly(N-vinylcarbazole) (PVK) was deposited on top of ITO substrates. The resulting hybrid organic/inorganic film was characterized by electrochemistry, FT-IR spectroscopy, microscopies and spectroelectrochemistry. Interestingly, an electrochromic behavior could be evidenced from the resulting composite.

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.

Four perovskites (LaTiO3, LaCrO3, La0.6Sr0.4MnO3 and MAPbI3) are proposed here as new photoinitiators (e.g., free radical generators) in combination with iodonium salt and optionally another additive (N-vinylcarbazole—NVK) to initiate both radical and cationic photopolymerization reactions. The proposed systems are efficient phenyl radical generators under polychromatic light sources such as a halogen lamp or a Xe–Hg lamp. The interest of this approach is the ability to work with very stable inorganic structures as photoinitiators. To the best of our knowledge, this is the first time that perovskites are incorporated in photoinitiating systems. Photochemical mechanisms will be proposed as sustained by electron spin resonance spin trapping (ESR-ST) experiments.

ABSTRACTFour novel onium salts (onium‐polyoxometalate) have been synthesized and characterized. They contain a diphenyliodonium or a thianthrenium (TH) moiety and a polyoxomolybdate or a polyoxotungstate as new counter anions. Outstandingly, these counter anions are photochemically active and can sensitize the decomposition of the iodonium or TH moiety through an intramolecular electron transfer. The phenyl radicals generated upon UV light irradiation (Xe–Hg lamp) are very efficient to initiate the radical polymerization of acrylates. Cations are also generated for the cationic polymerization of epoxides. Remarkably, these novel iodonium and TH salts are characterized by a higher reactivity compared with that of the diphenyliodonium hexafluorophosphate and the commercial TH salt, respectively. Interpenetrating polymer networks can also be obtained under air through a concomitant cationic/radical photopolymerization of an epoxy/acrylate blend (monomer conversions > 65%). The photochemical mechanisms are studied by steady‐state photolysis, cyclic voltammetry, and electron spin resonance techniques. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 981–989

Novel modified electrodes exhibit excellent electrocatalytic performance for nitrite detection.

The polymetallic cation [Mo3S4(H2O)(9)](4+) was used as an inorganic precursor to generate new hybrid organic-inorganic chalcogenide clusters. Three organic compounds with flexible and hanging arms were synthesized and investigated as ligands for coordination complexes with the rigid and electroactive inorganic [MO3S4] unit. Interestingly, the [MO3S4] core formed hybrid structures with the flexible H(3)NDABu [N-(3-carboxypropyl)iminodiacetic acid] and H(3)NDAPr [N-(2-carboxyethyl)iminodiacetic acid] ligands, which were characterized by X-ray crystallography. Surprisingly, no crystals were isolated, when the more rigid H(3)NDABn [N-(4-methoxycarbonylbenzyl)iminodiacetic acid] ligand was used. The two coordination complexes [Mo3S4(NDABu)(HNDABu)(2)](3-) and [Mo3S4(HNDAPr)(3)](2-) were characterized by X-ray diffraction (XRD), IR spectroscopy, thermal gravimetric analysis (TGA), H-1 NMR spectroscopy, elemental analysis, and electrochemistry. The organic ligands H(3)NDABu, H(3)NDAPr, and H(3)NDABn were characterized by XRD, IR, HR mass, and C-13 and H-1 NMR spectroscopy. [Mo3S4(NDABu)(HNDABu)(2)](3-) and [Mo3S4(HNDAPr)(3)](2-) constitute promising preformed building blocks to generate new organic-inorganic hybrid molecular or extended materials.

alpha-Silicon polyoxomolybdates in combination with an iodonium salt and/or a silane are used to generate phenyl and/or silyl radicals as well as silylium cations upon UV light irradiation. These species can initiate the radical photopolymerization of acrylates, the cationic photopolymerization of epoxides and the photopolymerization of epoxy/acrylate blends (i.e. for the synthesis of interpenetrated polymer networks) thereby leading to the formation of polyoxometalate/polymer hybrid materials. The mechanical properties of e.g. the polyether films are affected by the presence of polyoxometalate in the matrix as shown by their dynamic mechanical analysis (DMA). The photochemical mechanisms are studied by steady state photolysis, cyclic voltammetry, and electron spin resonance techniques.

In order to develop novel electroactive hosts for biosensor design, the possibility to use nanostructured vanadate phases as alternatives to well-known V2O5 gels was studied. For this purpose, the formation of M[V3O8] and Mx[V6O16] (x = 1 and 2) oxides by the sol–gel process has been studied over a wide range of cations (M+ = Li+, Na+, K+, Cs+, and NH4+; M2+ = Ca2+, Mg2+ and Ba2+). By a combination of XRD, 51V NMR and SEM studies, it was possible to evidence the influence of the nature and hydration state of cations on the size and morphology of the resulting particles as well as on the kinetics of their formation. On this basis, K2[V6O16] was evaluated for glucose oxidase encapsulation, either via impregnation or co-precipitation methods. When compared to V2O5, these novel bioelectrodes exhibit higher stability under pH conditions of optimum enzymatic activity, as well as better sensitivity, and reproducibility for glucose detection via amperometric titration.

Heterometallic cuboidal clusters [Mo3S4M(H2O)(9)Cl](3+) M = Pd or Ni react with the trivacant [AsW9O33](9-) anion to give tetramodular complexes [(H2AsW9O33)(4){Mo3S4M(H2O)(5)}(2)](20-) (M = Pd for anion 2 and M = Ni for anion 3) in good yield. Both anions crystallized as single crystals of potassium salts to give K-2 and K-3 salts which have been characterized structurally by X-ray diffraction. Both compounds are isomorphous and the anions 2 and 3 are described as two dimeric moeties, associated by internal hydrogen bonds, electrostatic interactions involving four outer potassium ion and coordination bonds within a central {M2S2} unit containing a M-M metallic bond. Studies in solution reveal that the dimeric association is maintained in solution in the 2 x 10(-4)-2 x 10(-3) mol L-1 range. Conversely, in the presence of exogeneous ligands, such as iodide or pyridine the UV-vis data are consistent with the dissociation of the anion 2 into monomer through a Pd-L coordination bond (L = I- or Py). Furthermore, W-183 NMR spectrum of 2 shows that molecular structure of 2 is retained in solution. Elemental analysis and IR are also supplied. Electrochemical behavior of 2 and 3 are given and compared with the Pd or Ni free parent anion. The CVs are dominated mainly by irreversible reduction or oxidation processes, where the peak potentials appear dependent upon the ionic charge of the complex. However, the CVof the Pd-containing anion (2) is consistent with the deposition of Pd metal at the electrode, which gives rise to an oxidation process into palladium oxide.