Hydrogen-atom (H-atom) transfer at the surface of heterogeneous metal oxides has received significant attention owing to its relevance in energy conversion and storage processes. Here, we present the synthesis and characterization of an organofunctionalized polyoxovanadate cluster, (calix)VO(OH)(OMe) (calix = 4--butylcalix[4]arene). Through a series of equilibrium studies, we establish the BDFE(O-H) of the aquo ligand as 62.4 ± 0.2 kcal mol, indicating substantial bond weaking of water upon coordination to the cluster surface. Subsequent kinetic isotope effect studies and Eyring analysis indicate the mechanism by which the hydrogenation of organic substrates occurs proceeds through a concerted proton-electron transfer from the aquo ligand. Atomistic resolution of surface reactivity presents a novel route of hydrogenation reactivity from metal oxide surfaces through H-atom transfer from surface-bound water molecules.
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http://dx.doi.org/10.1039/d2sc04843d | DOI Listing |
Angew Chem Int Ed Engl
December 2024
Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education, National & Local United Engineering Laboratory for Power Battery Institution, Northeast Normal University, Changchun, Jilin, 130024, China.
Construction of metal-organic cages (MOCs) with internal modifications is a promising avenue to build enzyme-like cavities and unlocking the mystery of highly catalytic activity and selectivity of enzymes. However, current interests are mainly focused on single-metal-node cages, little achievement has been expended to metallocluster-based architectures, and the in situ endogenous generation of metal clusters. Herein, based on the hard-soft-acids-bases (HSAB), the metallocluster-based heterometallic MOC (CuVMOP) constructed of [CuOPz] and [VO(OCH)(SO)(CO)] clusters was obtained by one-pot method.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
Mechanistic understanding of the formation of clusters plays a role in designing the structure-dependent properties. Based on the fact that anions act as templates to form spherical polyoxovanadates, various structures were reported by changing anions in the synthetic solution. In this work, another factor in the formation of spherical polyoxometalates was demonstrated.
View Article and Find Full Text PDFNat Commun
November 2024
School of Chemistry & SFI AMBER Research Centre, Trinity College Dublin, The University of Dublin, College Green, Dublin, D02 PN40, Ireland.
Contrary to common chemical intuition, cation-π interactions can persist in polar, aqueous reaction solutions, rather than in dry non-coordinative solvent systems. This account highlights how alkali ion-π interactions impart distinctive structure-influencing supramolecular forces that can be exploited in the preparation of nanoscopic metal-organic capsules. The incorporation of alkali ions from polar solutions into molecular pockets promotes the assembly of otherwise inaccessible capsular entities whose structures are distinctive to those of common polyoxovanadate clusters in which {V=O} moieties usually point radially to the outside, shielding the molecular entities.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium.
Supramolecular functional materials can be used to overcome some of the most challenging tasks in materials science, where the dynamic nature of supramolecular interactions can be leveraged to fine-tune the properties of the material for a given task. The Lindqvist hexavanadate family of polyoxometalates (POMs) have emerged as particularly interesting candidates to be used in supramolecular materials due to their redox and Lewis acid properties that enable their application in the fields of energy conversion/storage or catalysis. Despite their promising potential, hexavanadate clusters are underrepresented in the field of supramolecular materials, mainly due to the synthetic challenges related to their inherent reactivity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
Polyoxometalates (POMs) are ideal components for reversible multi-electron storage in energy technologies. To-date, most redox-applications employ only single, individual POM species, which limits the number of electrons that can be stored within a given potential window. Here, we report that spontaneous redox self-equilibration during cluster synthesis leads to the formation of two structurally related polyoxovanadates which subsequently aggregate into co-crystals.
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