Selective Oxidation of Alkenes Catalyzed bydi-Iron-Substituted Silicotungstate with Highly Efficient Utilization of Hydrogen Peroxide

Mizuno, Noritaka; Nozaki, Chikateru; Kiyoto, Ikuro; Misono, Makoto

doi:10.1006/jcat.1998.2369

Cited by 37 publications

(21 citation statements)

References 19 publications

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“…Furthermore, lacunary species, which are formed by the removal of one or more of the addenda atoms from the typical inorganic clusters, can coordinate a broad diversity of different metal ions thereby creating new prospects in POM chemistry. These metal-substituted POMs have a customized coordination chemistry and reactivity [3,14], and have shown their potential in several catalytic reactions, ranging from the epoxidation of olefins and alkanes to the splitting of water [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Eu(III) luminescence and tryptophan fluorescence spectroscopy as a tool for understanding interactions between hen egg white lysozyme and metal-substituted Keggin type polyoxometalates

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Stroobants

Absillis

et al. 2015

Journal of Inorganic Biochemistry

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The interaction between the lacunary Keggin K7PW11O39, the Eu(III)-substituted Keggin K4EuPW11O39 (Eu-Keggin) and the Ce(IV)-substituted Keggin [Me2NH2]10[Ce(PW11O39)2] (Ce-Keggin) polyoxometalates (POMs), and the proteins hen egg white lysozyme (HEWL) and the structurally homologous α-lactalbumin (α-LA) was studied by steady state and time-resolved Eu(III) luminescence and tryptophan (Trp) fluorescence spectroscopy. The excitation spectrum of Eu-Keggin at lower concentrations ([Eu-Keggin]<100 μM) is dominated by a ligand-to-metal charge transfer band (291 nm). For higher concentrations ([Eu-Keggin]>250 μM) the (5)L6←(7)F0 transition becomes the most intense peak. In the absence of protein, the number of coordinated water molecules to the Eu(III) centre of Eu-Keggin is 4, indicating a 1:1 Eu(III):POM species. In the presence of phosphate buffer this number linearly decreases from 4 to 2 upon increasing phosphate buffer concentration. Upon addition of HEWL, there are no coordinated water molecules, suggesting interaction between Eu-Keggin and the protein surface. In addition, this interaction results in a more than threefold increase of the hypersensitive (5)D0→(7)F2 transition for the Eu-Keggin/HEWL mixture. The calculated association constant amounted to 2.2×10(2) M(-1) for the Eu-Keggin/HEWL complex. Tryptophan fluorescence quenching studies were performed and the quenching constants were calculated to be 9.1×10(4) M(-1), 4×10(4) M(-1) and 4.1×10(5) M(-1) for the lacunary Keggin/HEWL, the Eu-Keggin/HEWL and the Ce-Keggin/HEWL complexes, respectively. The number of bound POM molecules to HEWL was 1.04 for the lacunary Keggin POM, and 1.0 for Eu-Keggin, indicating the formation of a 1:1 POM/HEWL complex. The value of 1.38 for Ce-Keggin might indicate a transition from 1:1 to 1:2 interaction.

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Section: Introductionmentioning

confidence: 99%

Eu(III) luminescence and tryptophan fluorescence spectroscopy as a tool for understanding interactions between hen egg white lysozyme and metal-substituted Keggin type polyoxometalates

Goovaerts

Stroobants

Absillis

et al. 2015

Journal of Inorganic Biochemistry

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“…To our knowledge, only a few publications involving allylic oxidation can be found about the oxidation of cycloalkenes catalyzed by TMSPs with H 2 O 2 or O 2 . Mizuno et al.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of Cyclohexene in the Presence of Transition‐Metal‐Substituted Phosphotungstates and Hydrogen Peroxide: Catalysis and Reaction Pathways

et al. 2017

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Homogeneous catalytic oxidations of cyclohexene by transition‐metal‐substituted phosphotungstates [PW11M(L)O39]m− (PW11M, M=CoII, CuII, FeIII, NiII, MnII, L=H2O or absence) with hydrogen peroxide in acetonitrile were experimentally studied. The catalytic activities of allylic oxidation were found to strongly depend on the transition metals, and PW11Co showed the highest activity. The product distribution and the catalyst stability were dominated by mole ratio of hydrogen peroxide to PW11M, whereby low or high mole ratios led to stable structure of PW11M and predominant formation of allylic oxidation products or decomposition of PW11M, respectively. Different from the activation of the allylic C−H bond by radicals, the oxidation of C=C double bond was based on tungsten‐peroxo species. A reaction mechanism composed of radical and nonradical processes was proposed from NMR, EPR, and kinetic data, to describe the reaction pathways of cyclohexene oxidation.

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“…Moreover, the removal of one or more of the addenda atoms from the POM framework results in the formation of a lacunary species, which can coordinate different metal ions, resulting in the formation of metal-substituted POMs [11,25]. Metal-substituted POMs have been used as catalysts in several catalytic reactions, ranging from the epoxidation of olefins and alkanes to the splitting of water [26][27][28][29]. Additionally, POMs exhibit biological activity, which includes in vitro and in vivo anticancer, antiviral, antibiotic, antiprotozoal and antidiabetic activity [23,24,30].…”

Section: Introductionmentioning

confidence: 99%

Understanding the Regioselective Hydrolysis of Human Serum Albumin by Zr(IV)-Substituted Polyoxotungstates Using Tryptophan Fluorescence Spectroscopy

et al. 2015

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Selective Oxidation of Alkenes Catalyzed bydi-Iron-Substituted Silicotungstate with Highly Efficient Utilization of Hydrogen Peroxide

Cited by 37 publications

References 19 publications

Eu(III) luminescence and tryptophan fluorescence spectroscopy as a tool for understanding interactions between hen egg white lysozyme and metal-substituted Keggin type polyoxometalates

Eu(III) luminescence and tryptophan fluorescence spectroscopy as a tool for understanding interactions between hen egg white lysozyme and metal-substituted Keggin type polyoxometalates

Oxidation of Cyclohexene in the Presence of Transition‐Metal‐Substituted Phosphotungstates and Hydrogen Peroxide: Catalysis and Reaction Pathways

Understanding the Regioselective Hydrolysis of Human Serum Albumin by Zr(IV)-Substituted Polyoxotungstates Using Tryptophan Fluorescence Spectroscopy

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