Oxidation of adamantane with 1 atm molecular oxygen by vanadium-substituted polyoxometalates

Shinachi, Satoshi; Matsushita, Mitsunori; Yamaguchi, Kazuya; Mizuno, Noritaka

doi:10.1016/j.jcat.2005.04.012

Cited by 69 publications

(10 citation statements)

References 54 publications

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“…In comparison, the catalytic activity of V 2 O 5 is lower than that of the vanadium-containing Keggin-type heteropolyacid (50% conversion after 6 h) despite the higher content of V atoms. These results are consistent with those reported by other authors, which suggests that vanadium constitutes the catalytic center for this reaction, while the Keggin-type framework serves as scaffold to enhance its activity …”

Section: Resultssupporting

confidence: 93%

A Robust Open Framework Formed by Decavanadate Clusters and Copper(II) Complexes of Macrocyclic Polyamines: Permanent Microporosity and Catalytic Oxidation of Cycloalkanes

Martín-Caballero

Wéry

Reinoso³

et al. 2016

Inorg. Chem.

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The first decavanadate-based microporous hybrid, namely, [Cu(cyclam)][{Cu(cyclam)}2(V10O28)]·10H2O(1, cyclam = 1,4,8,11-tetraazacyclotetradecane) has been prepared by reaction of (VO3) -anions and {Cu(cyclam)} 2+ complexes in NaCl (aq) at pH 4.6-4.7, and characterized by elemental analyses, thermogravimetry, and X-ray diffraction techniques (powder, single-crystal). Compound 1 exhibits a POMOF-like supramolecular open-framework built up of covalent decavanadate/metalorganic layers with square-like voids, the stacking of which is aided by interlamellar cementing complexes and generates water-filled channels with approximate cross-sections of. 10.4 × 8.8 Å 2 . The framework is robust enough to remain virtually unaltered upon thermal evacuation of all water molecules of hydration, as demonstrated through single-crystal X-ray diffraction studies on the anhydrous phase 1a. This permanent microporosity renders interesting functionality to 1, such as selective adsorption of CO2 over N2 and remarkable activity as heterogeneous catalyst toward the H2O2-based oxidation of the highly-stable, tricyclic alkane adamantane.Porous crystalline materials such as metal organic frameworks (MOFs) have attracted great attention due to their wide range of relevant applications. 1 These materials are constructed by coordination of metal ions or metalcontaining units (nodes) to organic bridging ligands (linkers) to form open crystalline frameworks with permanent porosity. This feature qualifies them as suitable candidates for gas storage and separation, ion exchange, host-guest chemistry, magnetism, biomedicine and catalysis. 2 However, the synthesis of MOFs usually requires harsh conditions (e.g. high temperature or pressure, prolonged reaction times, harmful solvents, etc.), and removal of guest molecules from their cavities often leads to the collapse of the porous structure when flexible linkers are used. In this context, the incorporation of rigid and voluminous species such as metal clusters could increase the overall robustness

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Section: Resultssupporting

confidence: 93%

A Robust Open Framework Formed by Decavanadate Clusters and Copper(II) Complexes of Macrocyclic Polyamines: Permanent Microporosity and Catalytic Oxidation of Cycloalkanes

Martín-Caballero

Wéry

Reinoso³

et al. 2016

Inorg. Chem.

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“…With substrates possessing aromatic functionality, this reduction typically occurs via electron transfer from the aromatic ring to the POM . With alkyl substrates, electrochemical reduction or sacrificial reductant ,, can be used to prime the POM for reaction with molecular oxygen. Here, we selected isobutyraldehyde as a sacrificial reductant.…”

Section: Resultsmentioning

confidence: 99%

“…Here, we employ the POM, decamolybdodivanado phosphoric acid (H 5 PV 2 Mo 10 O 40 ), immobilized in NU-1000 (Figure left and right) for the catalytic oxidation of CEES. H 5 PV 2 Mo 10 O 40 exists as five inseparable isomers and has been used as a catalyst in peroxide-based and O 2 -based oxidation reactions both homogeneously in solution , and heterogeneously on a variety of support materials. − Notably, this POM has been widely reported for its utility in desulfurization of diesel, , the mechanism of which relies upon an initial electron transfer step from the α-aryl group to reduce the POM . Few reports attempt to immobilize these POMs on crystalline supports to, not only improve stability, but also investigate the structure in detail to tune reactivity.…”

Section: Introductionmentioning

confidence: 99%

H₅PV₂Mo₁₀O₄₀ Polyoxometalate Encapsulated in NU-1000 Metal–Organic Framework for Aerobic Oxidation of a Mustard Gas Simulant

Buru

Wasson

Farha

2019

ACS Appl. Nano Mater.

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The immobilization of H5PV2Mo10O40 polyoxometalates (POMs) in the in the mesoporous channel-type metal–organic framework (MOF), NU-1000, via simple impregnation method is reported here. Characterization of the composite PV2Mo10@NU-1000 activated by supercritical CO2 revealed that the POMs occupy the mesopore. Upon heating as low as 40 °C in the absence of bulk solvent, the POMs migrate to the micropore. However, the presence of solvent, such as cyclohexane, impedes this transformation. The material was active for the aerobic oxidation of the mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES), in cyclohexane using isobutyraldehyde a sacrificial reductant and O2 as the oxidant. The activity of the POM allowed for efficient oxidation of CEES in the dark and in air. Immobilization of the POM in the MOF was found to improve the initial turnover frequency compared to the POM itself. Further, the POM catalyst was found to be unstable under the chosen reaction conditions and no activity was found upon washing and reusing the POM. As a composite PV2Mo10@NU-1000, the POMs retained their catalytic activity and allowed for recycling of the catalytic material.

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“…There is also a considerable body of literature on the autoxidation of various hydrocarbon substrates such as cyclohexene, cyclohexane, ethylbenzene, p -xylene, and long chain alkanes. − There was also a report on the aerobic epoxidation of linear alkenes, using an iron-substituted polyoxometalate. Initial reports suggested that selectivity was very high, but it would appear that the results obtained are commensurate with autoxidation. , As a word of caution, in our experience even slight/trace contamination of linear alkene with an aldehyde can considerably influence reaction selectivity.…”

Section: Activation Of Dioxygenmentioning

confidence: 99%

Dioxygen in Polyoxometalate Mediated Reactions

2017

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In this review article, we consider the use of molecular oxygen in reactions mediated by polyoxometalates. Polyoxometalates are anionic metal oxide clusters of a variety of structures that are soluble in liquid phases and therefore amenable to homogeneous catalytic transformations. Often, they are active for electron transfer oxidations of a myriad of substrates and upon reduction can be reoxidized by molecular oxygen. For example, the phosphovanadomolybdate, HPVMoO, can oxidize Pd(0) thereby enabling aerobic reactions catalyzed by Pd and HPVMoO. In a similar vein, polyoxometalates can stabilize metal nanoparticles, leading to additional transformations. Furthermore, electron transfer oxidation of other substrates such as halides and sulfur-containing compounds is possible. More uniquely, HPVMoO and its analogues can mediate electron transfer-oxygen transfer reactions where oxygen atoms are transferred from the polyoxometalate to the substrate. This unique property has enabled correspondingly unique transformations involving carbon-carbon, carbon-hydrogen, and carbon-metal bond activation. The pathway for the reoxidation of vanadomolybdates with O appears to be an inner-sphere reaction, but the oxidation of one-electron reduced polyoxotungstates has been shown through intensive research to be an outer-sphere reaction. Beyond electron transfer and electron transfer-oxygen transfer aerobic transformations, there a few examples of apparent dioxygenase activity where both oxygen atoms are donated to a substrate.

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Oxidation of adamantane with 1 atm molecular oxygen by vanadium-substituted polyoxometalates

Cited by 69 publications

References 54 publications

A Robust Open Framework Formed by Decavanadate Clusters and Copper(II) Complexes of Macrocyclic Polyamines: Permanent Microporosity and Catalytic Oxidation of Cycloalkanes

A Robust Open Framework Formed by Decavanadate Clusters and Copper(II) Complexes of Macrocyclic Polyamines: Permanent Microporosity and Catalytic Oxidation of Cycloalkanes

H₅PV₂Mo₁₀O₄₀ Polyoxometalate Encapsulated in NU-1000 Metal–Organic Framework for Aerobic Oxidation of a Mustard Gas Simulant

Dioxygen in Polyoxometalate Mediated Reactions

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Oxidation of adamantane with 1 atm molecular oxygen by vanadium-substituted polyoxometalates

Cited by 69 publications

References 54 publications

A Robust Open Framework Formed by Decavanadate Clusters and Copper(II) Complexes of Macrocyclic Polyamines: Permanent Microporosity and Catalytic Oxidation of Cycloalkanes

A Robust Open Framework Formed by Decavanadate Clusters and Copper(II) Complexes of Macrocyclic Polyamines: Permanent Microporosity and Catalytic Oxidation of Cycloalkanes

H5PV2Mo10O40 Polyoxometalate Encapsulated in NU-1000 Metal–Organic Framework for Aerobic Oxidation of a Mustard Gas Simulant

Dioxygen in Polyoxometalate Mediated Reactions

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H₅PV₂Mo₁₀O₄₀ Polyoxometalate Encapsulated in NU-1000 Metal–Organic Framework for Aerobic Oxidation of a Mustard Gas Simulant