Browsing by Author "Kortz, U."

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    Characterization of PtIV-containing polyoxometalates by high-resolution solid-state 195Pt and 51V NMR spectroscopy
    (2016) Dugar, S.; Izarova, N.V.; Mal, S.S.; Fu, R.; Joo, H.-C.; Lee, U.; Dalal, N.S.; Pope, M.T.; Jameson, G.B.; Kortz, U.
    We report on the feasibility of applying high-resolution solid-state 195Pt MAS NMR spectroscopy for several PtIV-containing polyoxotungstates, and of 195Pt as well as 51V for a PtIV-containing polyoxovanadate. This method is particularly useful for polyanions which are unstable in solution and/or poorly soluble, as well as for systems exhibiting crystallographic disorder of Pt and W sites. We also report solution 195Pt and 183W NMR spectra of hexatungstoplatinate(iv) [H3PtW6O24]5- for the first time. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016.
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    Characterization of PtIV-containing polyoxometalates by high-resolution solid-state 195Pt and 51V NMR spectroscopy
    (Royal Society of Chemistry, 2016) Dugar, S.; Izarova, N.V.; Mal, S.S.; Fu, R.; Joo, H.-C.; Lee, U.; Dalal, N.S.; Pope, M.T.; Jameson, G.B.; Kortz, U.
    We report on the feasibility of applying high-resolution solid-state 195Pt MAS NMR spectroscopy for several PtIV-containing polyoxotungstates, and of 195Pt as well as 51V for a PtIV-containing polyoxovanadate. This method is particularly useful for polyanions which are unstable in solution and/or poorly soluble, as well as for systems exhibiting crystallographic disorder of Pt and W sites. We also report solution 195Pt and 183W NMR spectra of hexatungstoplatinate(iv) [H3PtW6O24]5- for the first time. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016.
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    Electrocatalysis by crown-type polyoxometalates multi-substituted by transition metal ions
    (Comparative study) Naseer, R.; Mal, S.S.; Kortz, U.; Armstrong, G.; Laffir, F.; Dickinson, C.; Vagin, M.; McCormac, T.
    10.1016/j.electacta.2015.07.152
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    Electrocatalysis by crown-type polyoxometalates multi-substituted by transition metal ions; Comparative study
    (Elsevier Ltd, 2015) Naseer, R.; Mal, S.S.; Kortz, U.; Armstrong, G.; Laffir, F.; Dickinson, C.; Vagin, M.; McCormac, T.
    Abstract The difference in electrochemical properties of three crown-type polyoxometalates multi-substituted by Fe3+, Ni2+ or Co2+ ions and their precursor has been rationalized with respect to their electrocatalytic performances studied in solution and in the immobilized state within the layer-by-layer film formed with a positively charged pentaerythritol-based Ru(II)-metallodendrimer. The film assembly was monitored with electrochemical methods and characterized by surface analysis techniques. An influence of the terminal layer on the electrode reaction and on film porosity has been observed. The electrocatalytic performance of the compounds on nitrite reduction was assessed in solution and in the immobilized state. © 2015 Elsevier Ltd.
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    The cyclic 48-tungsto-8-phosphate [H7P8W48O184]33− Contant-Tézé polyanion and its derivatives [H6P4W24O94]18− and [H2P2W12O48]12−: structural aspects and reactivity
    (Royal Society of Chemistry, 2025) Mal, S.S.; Banerjee, A.; Kortz, U.
    Polyoxometalates (POMs) are discrete, anionic metal-oxo clusters of early transition metals in high oxidation states (e.g., WVI, MoVI, VV) usually comprised of edge- and corner-shared MO6 octahedra. Lacunary POMs are defect heteropolyanions mainly of the Keggin or Dawson type, and they can be formed by the loss of one or more MO6 octahedra by controlled base hydrolysis. The largest subclass of POMs are tungstophosphates, and several lacunary derivatives are known, such as the Keggin-based [PW11O39]7− and [PW9O34]9−, and the Dawson-based [P2W17O61]10− and [P2W15O56]12−. This review is based on the cyclic 48-tungsto-8-phosphate [H7P8W48O184]33− (P8W48) as well as its smaller derivatives [H6P4W24O94]18− (P4W24), and [H2P2W12O48]12− (P2W12), with a focus on structural aspects, solution stability and reactivity. All three polyanions can be considered as inorganic multidentate O-donor ligands that coordinate with d, f or p-block metal ions. Here we provide a comprehensive overview of guest metal-containing derivatives of the P8W48 wheel, the P4W24 half-wheel and the P2W12 quarter wheel. The structures containing P2W12 as a building unit are presented in a sequence of increasing number of POM units in the resulting assembly. Transition metal-containing POMs have been of interest for decades due to their remarkable capability of forming novel and unexpected structures associated with interesting and relevant physicochemical properties (e.g., catalysis, magnetism, biomedicine, electrochemistry), and this also applies for derivatives containing P8W48, P4W24 and P2W12 © 2025 The Royal Society of Chemistry.