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| Naji, M. |
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| Motta, Antonella |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Petrov, R. H. | Madrid |
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| Casati, R. |
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| Kočí, Jan | Prague |
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| Rančić, M. |
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| Azevedo, Nuno Monteiro |
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Monakhov, Kirill Yu
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (3/3 displayed)
- 2020Mononuclear zinc(II) Schiff base complexes as catalysts for the ring-opening polymerization of lactidecitations
- 2018Addressing Multiple Resistive States of Polyoxovanadatescitations
- 2017Molecular Characteristics of a Mixed-Valence Polyoxovanadate {VIV/V18O42} in Solution and at the Liquid-Surface Interfacecitations
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article
Molecular Characteristics of a Mixed-Valence Polyoxovanadate {VIV/V18O42} in Solution and at the Liquid-Surface Interface
Abstract
<p>The understanding of the molecular state of vanadium-oxo clusters (polyoxovanadates, POVs) in solution and on surface is a key to their target application in catalysis as well as molecular electronics and spintronics. We here report the results of a combined experimental and computational study of the behavior of nucleophilic polyoxoanions [V<sup>IV</sup><sub>10</sub>V<sup>V</sup><sub>8</sub>O<sub>42</sub>(I)]<sup>5-</sup> charged balanced by Et<sub>4</sub>N<sup>+</sup> in water, in a one-phase organic solution of N,N-dimethylformamid (DMF) or acetonitrile (MeCN), in a mixed solution of MeCN-water, and at the hybrid liquid-surface interface. The molecular characteristics of the compound (NEt<sub>4</sub>)<sub>5</sub>[V<sub>18</sub>O<sub>42</sub>(I)] (1) in the given environments were studied by microspectroscopic, electrochemical, scattering, and molecular mechanics methods. Contrary to the situation in pure water, where we observe great agglomeration with a number of intercalated H<sub>2</sub>O molecules between POVs that are surrounded by the Et<sub>4</sub>N<sup>+</sup> ions, no or only minor agglomeration of redox-active POVs in an unprecedented cation-mediated fashion was detected in pure DMF and MeCN, respectively. An inclusion of 1% water in the MeCN solution does not have an effect significant enough to reinforce agglomeration; however, this leads to the POV⋯POV interface characterized by the presence of the Et<sub>4</sub>N<sup>+</sup> ions and a small number of H<sub>2</sub>O molecules. Water amounts of ≥5% trigger the formation of higher oligomers. The deposition of compound 1 from MeCN onto an Au(111) surface affords nearly round-shaped particles (∼10 nm). The use of DMF instead of MeCN results in bigger, irregularly shaped particles (∼30 nm). This change of solvent gives rise to more extensive intermolecular interactions between polyoxoanions and their countercations as well as weaker binding of ion-pairing induced agglomerates to the metallic substrate. Lower concentration of adsorbed molecules leads to a submonolayer coverage and an accompanied change of the POV's redox state, whereas their higher concentration results in a multilayer coverage that offers the pristine mixed-valence structure of the polyoxoanion. Our study provides first important insights into the reactivity peculiarities of this redox-responsive material class on a solid support.</p>