Condensation of Keggin Anions Containing Chromium(III) and Aluminum(III), Respectively. 1. Synthesis and X-ray Structural Determination of [{A-.alpha.-SiO4W9O30(OH)3Cr3}2(OH)3]11-

Wassermann, Knut; Palm, Rosemarie; Lunk, Hans‐Joachim; Fuchs, Joachim; Steinfeldt, Norbert; Stoêsser, R.

doi:10.1021/ic00124a018

Cited by 59 publications

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“…In particular, Wassermann et al 17 reported an "almost ideal octahedral environment" for M ) Cr, whereas Yamase et al 18 found a strongly distorted octahedral environment for M ) Ti. Attempts have also been made to infer the symmetry of the substitutional metal site from the intensity of the visible region d-d transitions.…”

Section: Resultsmentioning

confidence: 99%

In SituVanadium K-Edge and Tungsten L_III-Edge X-ray Absorption Fine Structure of Vanadium-Substituted Heteropolytungstates Immobilized in a High-Area Carbon Electrode in Acid Aqueous Electrolytes

et al. 1996

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Electronic and structural aspects of vanadium-substituted heteropolytungstates immobilized in a high-area carbon (XC-72) as a function of oxidation state have been examined by in situ X-ray absorption near-edge structure (XANES) in an acidic electrolyte. The results obtained for K 4 PVW 11 O 40 revealed a sizable shift in the V K-edge XANES region, which is characterized by a prominent pre-edge peak, following a one-electron reduction. Such behavior has been attributed to the transfer of an electron to an orbital localized mainly on vanadium. Injection of a second electron gives rise to the near disappearance of the pre-edge peak without major shifts in the position of edge jump, a phenomenon ascribed to an increase in the symmetry of the vanadium site upon reduction to yield a nearly octahedral environment. Similar behavior is observed for Cs 6 PV 3 W 9 O 40 when the electrode is polarized in the potential regions where the vanadium ions are reduced to V IV and V III , respectively. No changes in the in situ W L III -edge XANES could be discerned for these vanadium-substituted heteropolytungstates in their various oxidation states, for which the spectral features were the same as those of H 3 PW 12 O 40 adsorbed on XC-72 under otherwise identical conditions.

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Section: Resultsmentioning

confidence: 99%

In SituVanadium K-Edge and Tungsten L_III-Edge X-ray Absorption Fine Structure of Vanadium-Substituted Heteropolytungstates Immobilized in a High-Area Carbon Electrode in Acid Aqueous Electrolytes

et al. 1996

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“…pounds, constructed through supramolecular assembly: Na 19 K 4 [(SiW 9 O 34 )(SiW 9 O 33 (OH))(Cu(OH)) 6 Cu] 2 X·nH 2 O (X = Cl, n = 160 2 Cl ; X = Cl, n = 90 2 Cl dhyd ; X = Br, n = 160 2 Br ; X = Br, n = 90 2 Br dhyd ; 2Cl dhyd and 2 Br hdyd are the dehydrated forms of 2 Cl and 2 Br, respectively).…”

mentioning

confidence: 99%

“…Compound 1 is an azido complex of general formula H 5 K 6 [(SiW 9 O 37 )-Cu 3 N 3 ]·19H 2 O obtained by mixing in water at room temperature stoichiometric amounts of [A,a-SiW 9 O 34 ] 10À , CuCl 2 , and NaN 3 . Compound 1 is an azido complex of general formula H 5 K 6 [(SiW 9 O 37 )-Cu 3 N 3 ]·19H 2 O obtained by mixing in water at room temperature stoichiometric amounts of [A,a-SiW 9 O 34 ] 10À , CuCl 2 , and NaN 3 .…”

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confidence: 99%

A Supramolecular Tetradecanuclear Copper(II) Polyoxotungstate

Dolbecq¹,

Marrot²,

Rivière³

et al. 2003

Angewandte Chemie

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Polyoxometalates (POMs) can be perceived as discrete fragments of extended metal oxide lattices.[1] They continue to attract much attention with respect to their widespread applications.[ , V IV,V ) respectively. These species are diamagnetic when the metals M are in their highest oxidation state. Mono, di and trivacant species of the Keggin type polyoxotungstates can be easily prepared, [3] and then act as nucleophilic ligands for transition-metal (TM) or rare-earth cations. Such inclusions can then lead to the formation of magnetic clusters. Trivacant POMs are the best candidates to obtain compounds with the largest number of interacting magnetic cations. Recently, compounds with a number (from one to nine) of paramagnetic TM centers of the first row ranging were reported.[

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“…The observation of discrete forbidden transitions in Al 2 03 and related powders was restricted in this contribution essentially to the low-field region (see Figs 4,[6][7][8][9]. Restricting to the systems investigated here the simulations reveal (Figs.…”

Section: Spectral Effects and Simulationsmentioning

confidence: 89%

“…All simulations presented here used a program which is based on the complete diagonalization of the full spin-Hamiltonian matrix for the S = 5/2 problem [7,8]. The calculations of the powder spectra were performed for both the allowed and the forbidden transitions (mainly occurring between the 1/2 and 3/2 manifolds).…”

Section: Simulationsmentioning

confidence: 99%

Fe3+ ions in amorphous solids: EPR on mechanically and chemically amorphized Al2O3

Stößer

Scholz

1998

Appl. Magn. Reson.

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Stepwise amorphization of a low-level doped a-Al 2 03 single crystal yielded powders without changes of the concentration and chemical nature of the dopants. Kind and degree of disturbances could be unambiguously monitored by the allowed and forbidden transitions of the Fe 3 '-cw-EPR in X-band using a Bruker bimodal cavity. Based on simulations diagonalizing the spin Hamiltonian for S = 5/2 it was possible to discriminate between regions as well as samples of structural order and disorder. The spectral pattern of the allowed and forbidden transitions of Fe" ions together with the field-position-dependent saturation behaviour (4.2 K) allowed us to differentiate between crystalline and amorphous components or regions of a sample.

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Condensation of Keggin Anions Containing Chromium(III) and Aluminum(III), Respectively. 1. Synthesis and X-ray Structural Determination of [{A-.alpha.-SiO4W9O30(OH)3Cr3}2(OH)3]11-

Cited by 59 publications

References 0 publications

In SituVanadium K-Edge and Tungsten L_III-Edge X-ray Absorption Fine Structure of Vanadium-Substituted Heteropolytungstates Immobilized in a High-Area Carbon Electrode in Acid Aqueous Electrolytes

In SituVanadium K-Edge and Tungsten L_III-Edge X-ray Absorption Fine Structure of Vanadium-Substituted Heteropolytungstates Immobilized in a High-Area Carbon Electrode in Acid Aqueous Electrolytes

A Supramolecular Tetradecanuclear Copper(II) Polyoxotungstate

Fe3+ ions in amorphous solids: EPR on mechanically and chemically amorphized Al2O3

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Condensation of Keggin Anions Containing Chromium(III) and Aluminum(III), Respectively. 1. Synthesis and X-ray Structural Determination of [{A-.alpha.-SiO4W9O30(OH)3Cr3}2(OH)3]11-

Cited by 59 publications

References 0 publications

In SituVanadium K-Edge and Tungsten LIII-Edge X-ray Absorption Fine Structure of Vanadium-Substituted Heteropolytungstates Immobilized in a High-Area Carbon Electrode in Acid Aqueous Electrolytes

In SituVanadium K-Edge and Tungsten LIII-Edge X-ray Absorption Fine Structure of Vanadium-Substituted Heteropolytungstates Immobilized in a High-Area Carbon Electrode in Acid Aqueous Electrolytes

A Supramolecular Tetradecanuclear Copper(II) Polyoxotungstate

Fe3+ ions in amorphous solids: EPR on mechanically and chemically amorphized Al2O3

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Product

Resources

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In SituVanadium K-Edge and Tungsten L_III-Edge X-ray Absorption Fine Structure of Vanadium-Substituted Heteropolytungstates Immobilized in a High-Area Carbon Electrode in Acid Aqueous Electrolytes

In SituVanadium K-Edge and Tungsten L_III-Edge X-ray Absorption Fine Structure of Vanadium-Substituted Heteropolytungstates Immobilized in a High-Area Carbon Electrode in Acid Aqueous Electrolytes