Temperature-dependent gel-type ionic liquid compounds based on vanadium-substituted polyoxometalates with Keggin structure

Abstract

A series of temperature-dependent gel-type ionic liquid compounds have been synthesized from 1-(3-sulfonic group) propyl-3-methyl imidazolium (abbreviated as MIMPS) and three vanadium-substituted heteropoly acids H5SiW11VO40, H5SiMo11VO40 and H7SiW9V3O40. The designed and synthesized gel-type polyoxometalate ionic liquids (POM-ILs) have demonstrated a tendency to exhibit a layered structure. Moreover, they can undergo a phase transformation from a viscous gel-state to a liquid-state below 100 °C, and ionic conductivity up to 10(-3) S cm(-1) was observed at 120 °C. Cyclic voltammetry was carried out to study their electrochemical properties in organic solutions, and it was found that the oxidizability of the three POM-ILs decreases in the order: [MIMPS]7SiW9V3O40 > [MIMPS]5SiMo11VO40 > [MIMPS]5SiW11VO40. This result indicates that the redox behavior can be tuned by changing the chemical composition of the heteropolyanions.

Synthesis and Characterization of a Novel Polyoxometalate Gel Electrolyte

“…In this work, we have successfully synthesized novel polyoxometalate gel electrolyte by using 1-(3-sulfonic group) propyl-3-methyl imidazolium (MIMPS) and vanadium-substituted tungstosilicic acid H 5 40 , which demonstrates that the nature of the cation greatly influences the secondary structure of the polyoxometalate derivatives. …”

“…They possess some excellent properties such as thermodynamic stability, electrical conductivity and electrochemical properties. [2][3][4][5] Heteropolyacids and polyoxometalate, a class of discrete, negatively charged early transition metal oxide clusters, are formed based on inorganic metal-oxygen cluster anions. Some research in material science area pay more attention to the electrochemical performance of these compounds since they are perfect electron acceptors.…”

Preparation, characterization and heterogeneous catalytic applications of GO/Fe3O4/HPW nanocomposite in chemoselective and green oxidation of alcohols with aqueous H2O2

“…It should be emphasized that by heterogenization of HPAs, their activity is decreased relative to the initial catalyst and homogeneous conditions and the catalyst is probably leached out from the support surface in catalyst recycling. Therefore, the covalent or ionic nature of the interaction between HPA and the support surface is significant and affects the physicochemical properties, catalytic activity, and leaching of the active species . Various insoluble supports have been used for immobilization of HPAs such as silica, titana, alumina, zirconia, carbon, cellulose, zeolites and clays, metal oxides, organic materials and metal ‐ organic frameworks …”

Multicycle Testing of P‐Mo–V Heteropoly Acid Catalysts in Oxidation of Substituted Phenols

“…Heteropoly acids (HPAs) are particularly promising inorganic metal‐oxygen cluster compounds which were first discovered in 1826 ,. Among them, vanadium‐substituted HPAs have long attracted the attention of researchers worldwide and offer great prospects in various applications . Over the years, these compounds have proven them to be efficient catalysts for diverse organic transformations due to their tunable physicochemical properties and unique structure …”