New Insights about Vanadium-containing POMs built from [AsW9O33]9- and Host-Guest Chemistry with Hybrid Lindqvist anions
Résumé
Polyoxometalates (POMs) are polyanions composed mainly of Mo, W and V in their highest oxidation states. Due to their outstanding properties and structural diversity, POMs can be used in many fields of application, especially in environmental applications such as photodegradation of organic , and inorganic pollutants. In this context, vanadium-containing POMs have a high redox potential and an absorption in the visible regions, appear as an interesting platform for the photo-oxidation of pollutants. Here, we report on the one hand, new perspectives on vanadium-containing heteropolytungtates (HPWVs) and on the other hand the host-guest chemistry of Lindqvist hybrid anions with cyclodextrins. HPWVs were synthesized in aqueous medium, from tri-lacunar Keggin containing heteroatoms (AsIII, SbIII, TeIV) and in the presence of vanadyls(VO2+). The characterization by XRD reveals that they consist of two tri-lacunar [XW9O33]n- {n= 9, (X= As, Sb); n=8, X=Te} units connected by a triangular or hexagonal belt composed of VO2+ vanadyls. In the course of our research, we also identified unconventional and novel arrangements of Keggin ions that were also identified and characterized in solution by NMR (see fig B). Then, the reactivity of these entities was studied in solution by UV-visible spectroscopy and electrochemistry.