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Title: Keggin (K{sub 5}, H{sub 3}O)[SiV{sub 3}W{sub 9}O{sub 40}H]·xH{sub 2}O: Characterization and crystal structure

Single crystals of the potassium salt (K{sub 5}, H{sub 3}O)[SiV{sub 3}W{sub 9}O{sub 40}H]·xH{sub 2}O of the vanadium tri-substituted α-Keggin dodecatungstosilicate were prepared and analyzed by vibrational, EPR and {sup 51}V NMR spectroscopy. Varying the synthesis conditions allows crystallization of partially reduced anions. The crystal structure was determined for both oxidized (V{sup 5+}) and partially reduced (V{sup 4+/5+}) potassium salts. Single crystal X-ray diffraction data and solid state {sup 51}V-NMR spectra confirm the occurrence of a single vanadium site in a cubic structure due to rotational disorder of the Keggin ion. Partially reduced compounds crystallize within the same structure as fully oxidized ones. EPR experiments confirm strong interaction of V{sup 4+} with two V{sup 5+} ions, in accordance with insertion of a V{sub 3} subunit into the lacunary Keggin ion as designed in the synthesis method. The 3D-edifice is composed of K{sup +}/H{sub 2}O counter-sublattice with evidence of tunable water occupancy. - Graphical abstract: Relative arrangements of HPA clusters in (K{sub 5}, H{sub 3}O)[SiV{sub 3}W{sub 9}O{sub 40}]·xH{sub 2}O. - Highlights: • We prepared single crystals of the potassium salt (K{sub 5}, H{sub 3}O)[SiV{sub 3}W{sub 9}O{sub 40}H]·xH{sub 2}O. • The synthesis was designed to give the α-1,2,3-[SiV{sub 3}W{sub 9}O{sub 40}] Keggin ion.more » • Strict pH control was necessary to avoid vanadium partial reduction. • Reduced compounds crystallize within the same structure as fully oxidized ones. • EPR confirms strong interaction of V{sup 4+} with two V{sup 5+} ions in a V{sub 3} subunit.« less
Authors:
;  [1] ;  [1] ; ;  [2] ;  [3]
  1. Instituto de Química, Universidade Federal do Rio de Janeiro, Avenida Athos da Silveira Ramos, 149, Centro de Tecnologia, Bloco A - Sala 637, Cidade Universitária. 21941-909, Rio de Janeiro, RJ (Brazil)
  2. Université Lille Nord, Unité de Catalyse et de Chimie du Solide, UMR-CNRS 8181, U S T Lille (France)
  3. Université d'Aix-Marseille III (France)
Publication Date:
OSTI Identifier:
22334194
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 213; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CONTROL; CRYSTAL STRUCTURE; CRYSTALLIZATION; ELECTRON SPIN RESONANCE; MONOCRYSTALS; NMR SPECTRA; NUCLEAR MAGNETIC RESONANCE; POTASSIUM; SOLIDS; SPECTROSCOPY; STRONG INTERACTIONS; SYNTHESIS; VANADIUM; X-RAY DIFFRACTION