Incorporating highly basic polyoxometalate anions comprising Nb or Ta into nanoscale reaction fields of porous ionic crystals

Abstract

Polyoxometalates (POMs) are oxide cluster anions composed of high-valence early transition metals and widely used as catalysts. Yet base catalysis of POMs remains an ongoing challenge; group V (V, Nb,...

Single-ion chelation strategy for synthesis of monodisperse Pd nanoparticles anchored in MOF-808 for highly efficient hydrogenation and cascade reactions

“…In recent years, MOFs have been widely used in the Knoevenagel condensation reaction, taking advantage of their porous structure and size effect. 61,62 Inspired by this progress, the first step reaction using Pd@MOF-808-Pza as a catalyst mainly used the SBUs of Zr 6 atomic clusters and the Lewis acid active site of the Pza ligand in MOF-808. In the second step, the nitro product as a substrate was reduced to the amino product by Pd nanoparticles, and the enyl group is changed to the alkyl group, which was reduced due to the excessively strong reductivity of Pd nanoparticles.…”

A POM-based porous supramolecular framework for efficient sulfide–sulfoxide transformations with a low molar O/S ratio

“…Recently, there has been a surge in research interest on POM-based porous supramolecular frameworks with periodic and accessible channels because their non-covalent skeletons have strong reversibility and their porous structures also allow fast mass transfer. [38][39][40][41][42] However, few catalytic systems based on POM-based porous supramolecular frameworks have been exploited until now. 12,42,43 For instance, a porous framework with 27.6% void space constructed via the supramolecular stacking of Keggin-type POMs and metalloporphyrin layers has been shown to exhibit high activity towards the conversion of appropriately sized alkylbenzenes to ketones.…”

“…[38][39][40][41][42] However, few catalytic systems based on POM-based porous supramolecular frameworks have been exploited until now. 12,42,43 For instance, a porous framework with 27.6% void space constructed via the supramolecular stacking of Keggin-type POMs and metalloporphyrin layers has been shown to exhibit high activity towards the conversion of appropriately sized alkylbenzenes to ketones. 44 Zhang et al reported a feasible supramolecular self-assembly route to fabricate a series of POM-based porous frameworks with catalytic activity for dye degradation and esterification.…”

Three rare-earth incorporating 6-peroxotantalo-4-selenates and catalytic activities for imidation reaction

“…Thus, even after decades of research, the progress on POTas is still severely limited owing to the challenge in controlling the formation of intractable gel-like materials or insoluble Ta 2 O 5 precipitate. 9–15 Hill, 16 Liu, 17 Zhang, 18 Su 19 and Yue 20 have proved that the use of H 2 O 2 can extend the synthesis to acidic solutions, depending on which peroxo groups on niobium and tantalum were formed and thus provided better reactivity toward lacunary POM units. In this way, a series of mixed Nb/Ta–W POMs have been obtained.…”