Molybdenum/Tungsten‐Based Heteropoly Salts in Oxidations

Abstract

Oxidation represents one of the most important and practical chemical transformations for both organic synthesis, material science and pharmaceutical area. Among the existing strategies, molybdenum/tungsten-based heteropoly salts involved oxidations with low-cost and environmentally benign terminal oxidant and thus have attracted considerable attention in recent years. In this review, we have summarized the recent development of heteropoly salts utilized in oxidations, mainly the peroxomolybdates and peroxotungstates. We wish to highlight the progress made in the past 20 years of this field. Three categories are classified according to the aggregation state of metal oxides. Special attention is paid to the catalytically active peroxometalate species generated during the oxidation process. It is helpful to shed light on the common features that enable highly efficient and selective oxidations. We aim to inspire fellow chemists to explore more functional metalates for catalytic oxidations, especially asymmetric versions. Meanwhile, we attempt to understand the design principles for the discovery of more efficient, selective and economical catalytic systems.

Biphasic Selective Oxidation of Cyclohexene with Dilute Aqueous Hydrogen Peroxide Using Phase Transfer Catalysts

“…After 15−20 min, the precipitated potassium chloride was filtered off, and the filtrate obtained was concentrated and dried in vacuum at 80 °C to give the product as a viscous offwhite liquid with 78% yield. 1 PO 4 ] or [3 + ][H 2 ]. 50 mmol of Nmethyl-2-pyrrolidone was placed in a round-bottom flask cooled in an ice bath, and an equimolar ratio of concentrated phosphoric acid was added to it dropwise.…”

“…After addition, the reaction mixture was stirred at 80 °C for 24 h. The reaction mixture was vacuum-dried at 80 °C to obtain the product as a viscous pale liquid in 90% yield. 1 (Sigma-Aldrich, ≥98% purity). The reaction mixtures were heated at 60 °C and vigorously mixed on a Glas-Col shaker plate at 500 rpm for 2 h. After completion, reaction mixtures were immediately cooled to cease the reaction, and products were extracted using 10−12 mL of dichloromethane.…”

“…Quantities of these species were estimated using the response factor of epoxide (Figure S5). 1 H NMR was recorded on a 500 MHz X500 Bruker Avance III HD (at IMSERC Northwestern) system by sampling 700 μL of aqueous extract of the cyclohexene oxidation reaction and D 2 O in a 9:1 ratio. solutions were prepared in a threeelectrode gas diffusion electrode (GDE) flow cell under oxygen reduction reaction (ORR) conditions.…”

Synthesis of modified amphiphilic quaternary ammonium silicotungstate and its application in heterogeneous catalytic oxidative desulfurization

“…In addition, the production of active components W-O-O and ˙OH has also been reported in the literature. 57 Hence, DBT was oxidized to DBTO 2 , and the peroxo transition structure unit with higher activity was reduced to WO. After the desulfurization reaction, the oxidation product DBTO 2 with stronger polarity was precipitated from the oil and adsorbed on the surface and pores of the (HTA) 4 -SiW anion.…”

A dual-mode system based on molybdophosphoric heteropoly acid and fluorescent microspheres for the reliable and ultrasensitive detection of alkaline phosphatase

“…Heteropoly acids are inorganic materials, consisting of oxoclusters of transition metals in highest oxidation states, typically Mo, W, and V. Because of their various merits (excellent redox activity, low toxicity, and multifarious structures), they have been arousing great attention in the fields of disease diagnostics and cancer therapy. [1][2][3][4][5] In particular, some heteropoly acids-based probes have been reported for the assay of hydrogen peroxide, 6 ascorbic acid, 7 glucose, 8 and uric acid 9 and others. 10 Apart from applications in colorimetric assays, heteropoly acids have also been used as catalysts upon combination with fluorescent probes for highly sensitive and rapid determination of biomolecules.…”