English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Dissolution of the polyoxometalate (POM) cluster anion H 5 [PV 2 Mo 10 O 40 ] ( 1 ; a mixture of positional isomers) in 50% aq H 2 SO 4 dramatically enhances its ability to oxidize methylarenes, while fully retaining the high selectivities typical of this versatile oxidant. To better understand this impressive reactivity, we now provide new information regarding the nature of 1 (115 mM) in 50% (9.4 M) H 2 SO 4 . Data from 51 V NMR spectroscopy and cyclic voltammetry reveal that as the volume of H 2 SO 4 in water is incrementally increased to 50%, V(V) ions are stoichiometrically released from 1 , generating two reactive pervanadyl, VO 2  + , ions, each with a one-electron reduction potential of ca. 0.95 V (versus Ag/AgCl), compared to 0.46 V for 1 in 1.0 M aq H 2 SO 4 . Phosphorus-31 NMR spectra obtained in parallel reveal the presence of PO 4  3- , which at 50% H 2 SO 4 accounts for all the P(V) initially present in 1 . Addition of (NH 4 ) 2 SO 4 leads to the formation of crystalline [NH 4 ] 6 [Mo 2 O 5 (SO 4 ) 4 ] (34% yield based on Mo), whose structure (from single-crystal X-ray diffraction) features a corner-shared, permolybdenyl [Mo 2 O 5 ] 2+ core, conceptually derived by acid condensation of two MoO 3 moieties. While 1 in 50% aq H 2 SO 4 oxidizes p -xylene to p -methylbenzaldehyde with conversion and selectivity both greater than 90%, reaction with VO 2  + alone gives the same high conversion, but at a significantly lower selectivity. Importantly, selectivity is fully restored by adding [NH 4 ] 6 [Mo 2 O 5 (SO 4 ) 4 ], suggesting a central role for Mo(VI) in attenuating the (generally) poor selectivity achievable using VO 2  + alone. Finally, 31 P and 51 V NMR spectra show that intact 1 is fully restored upon dilution to 1 M H 2 SO 4 .

Selective Oxidation by H5[PV2Mo10O40] in a Highly Acidic Medium

Selective Oxidation by H₅[PV₂Mo₁₀O₄₀] in a Highly Acidic Medium