Polyoxometalates: Fascinating structures, unique magnetic properties

Kortz, Ulrich; Müller, Achim; Slageren, Joris van; Schnack, Jürgen; Dalal, Naresh S.; Dressel, Martin

doi:10.1016/j.ccr.2009.01.014

Cited by 535 publications

(242 citation statements)

References 84 publications

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“…Th e polyoxometalates, as transitional metal-oxygen clusters, are a class of inorganic compounds with controllable shapes and sizes, and with excellent properties that make them attractive for various applications [1,2]. Th is study follows the comparative UV and IR spectra of Keggin type polyoxometalates.…”

Section: Introductionmentioning

confidence: 99%

The UV and IR Comparative Spectrophotometric Study of Some Saturated and Lacunary Polyoxometalates

Grama

Boda

Florea

et al. 2014

Acta Medica Marisiensis

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Objectives:The polyoxometalates are a class of inorganic compounds with controllable shapes and sizes, and with excellent properties that make them attractive for various applications. This study is aimed at the comparative UV and IR spectra of Keggin type polyoxometalates. Methods: Compounds under (UV and IR) investigations were divided into several groups to highlight similarities between compounds or classes of compounds for the same category. There are four types of saturated Keggin structures and six lacunar compounds included in this study. The study begins with the UV investigations on aqueous solutions with 10 -5 M concentration for these compounds. IR spectra were recorded as KBr pressed pellets. Results: The UV spectras presents large strong peaks between 185-195 nm corresponding to W = Od bonds, between 251-268 nm for W-O-W bridge bonds, depending on heteroatom types (As, Sb). The unsaturated cryptand ligand having Co 2+ coordinated presents the most intense peak, due to the involvement of oxygen atoms from terminal W = Od coordinative bonds with high electronic densities in coordination of W-O-Co bond. The IR spectra present many peaks that are associated as follows: for terminal bonds W = Od, 955-970 cm -1 ; for W-O-W bridging bonds, 790-910 cm -1 ; for W-O-As/Sb bonds to heteroatom, 690-760 cm -1 . Vibrations of the bonds between heteroatoms and oxygen (As/Sb-O) appear around 620-660 cm -1 . Conclusions: Similarities appear from the recorded spectra, between compounds of the same class, by category association. Very fi ne displacements of peaks that occur explain the infl uence of heteroatoms, addenda atoms or coordinated cations.

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Section: Introductionmentioning

confidence: 99%

The UV and IR Comparative Spectrophotometric Study of Some Saturated and Lacunary Polyoxometalates

Grama

Boda

Florea

et al. 2014

Acta Medica Marisiensis

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“…Polyoxometalate (POM) chemistry has gained much attention in recent years, due to potential applications in catalysis, magnetism, material science, and even biomedical systems [1][2][3][4][5][6][7][8][9][10]. Most of the OPEN ACCESS work in this area has been focused on 3d transition metal-containing derivatives [11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of 8-Yttrium(III)-Containing 81-Tungsto-8-Arsenate(III), [Y8(CH3COO)(H2O)18(As2W19O68)4(W2O6)2(WO4)]43−

2015

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Abstract:The 8-yttrium(III)-containing 81-tungsto-8-arsenate(III) [Y8(CH3COO)(H2O)18(As2W19O68)4(W2O6)2(WO4)] 43− (1) has been synthesized in a one-pot reaction of yttrium(III) ions with [B-α-AsW9O33] 9− in 1 M NaOAc/HOAc buffer at pH 4.8.Polyanion 1 is composed of four {As2W19O68} units, two {W2O10} fragments, one {WO6} group, and eight Y III ions. The hydrated cesium-sodium salt of 1 (CsNa-1) was characterized in the solid-state by single-crystal XRD, FT-IR spectroscopy, thermogravimetric and elemental analyses.

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“…4, 5 Noyori reported various polyoxometalate (POM) catalysts in the oxidation of organic compounds with aqueous H 2 O 2 as the oxidant. (POMs) [6][7][8][9] have widely been used in the catalytic oxidation reaction due to their oxidative stability and high efficiency. [10][11][12] The homogeneous catalysis is green, highly efficient and environmentally pollution-free, 13,14 but there are inherent problems existing with this method such as the difficult separation of the product and thus the catalyst is easily lost in the process.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of Cyclohexanol on Phosphotungstic Acid Anion Intercalated Layered Double Hydroxides With Aqueous H2o2 as Oxidant

Bai

Xue

et al. 2017

Quim. Nova

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The layered double hydroxides (LDH) of Mg 2 AlNi and Mg 3 Al pillared by Keggin-type phosphotungstic acid anion (POM), i.e. Mg 2 AlNi-POM LDH and Mg 3 Al-POM LDH were synthesized by an ion-exchange method. The synthesized POM intercalated LDH compounds were characterized using various techniques such as FTIR, XRD, TGA and BET. The observed results show that the obtained catalysts retain the layer structure of LDH. Compared with the binary Mg 3 Al-POM LDH, the ternary Mg 2 AlNi-POM LDH catalyst indicated a higher thermal and chemical stability. The catalytic activity of the resulting LDH-POM was also assessed in the green oxidation of cyclohexanol with aqueous H 2 O 2 as an oxidant. The Mg 2 AlNi-POM LDH showed a much higher conversion and selectivity for cyclohexanone than the corresponding Mg 3 Al-POM LDH catalyst.

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Polyoxometalates: Fascinating structures, unique magnetic properties

Cited by 535 publications

References 84 publications

The UV and IR Comparative Spectrophotometric Study of Some Saturated and Lacunary Polyoxometalates

The UV and IR Comparative Spectrophotometric Study of Some Saturated and Lacunary Polyoxometalates

Synthesis and Characterization of 8-Yttrium(III)-Containing 81-Tungsto-8-Arsenate(III), [Y8(CH3COO)(H2O)18(As2W19O68)4(W2O6)2(WO4)]43−

Oxidation of Cyclohexanol on Phosphotungstic Acid Anion Intercalated Layered Double Hydroxides With Aqueous H2o2 as Oxidant

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