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Lookup NU author(s): Daniel Lebbie, Dr Thompson Izuagie, Dr Magda Pascual-BorrasORCiD, Balamurugan Kandasamy, Dr Corinne Wills, Dr Paul Waddell, Dr Ben HorrocksORCiD, Dr John ErringtonORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
An understanding of proton transfer and migration at the surfaces of solid metal oxides and related molecular polyoxometalates (POMs) and metal alkoxides is crucial for the development of reactivity involving protonation or the absorption/binding of water. In this work, the hydrolysis of alkoxido Ti- and Sn-substituted Lindqvist [(MeO)MW5O18]3–(M = Ti, 1; M = Sn, 2) and Keggin [(MeO)MPW11O39]4– (M = Ti, 3; M = Sn, 4) type polyoxometalates (POMs) to hydroxido derivatives and subsequent condensation to µ-oxido species has been investigated in detail to provide insight into proton transfer reactions in these molecular metal oxide systems. Solution NMR studies revealed the dependence of reactions not only on the nature of the heteroatom (Ti or Sn) but also on the type of lacunary (MW5 or PW11) POM and also on the solvent (MeCN or DMSO). Tin-substituted anions 2 and 4 were much more susceptible to protonolysis than the Ti analogues 1 and 3 while reactions of {MW5} anions were generally faster than those of the {MPW11} anions. Subsequent condensation of the resulting hydroxido derivatives [(HO)MW5O18]3– (M = Ti, 5; M = Sn, 6) and [(HO)MPW11O39]4– (M = Ti, 7; M = Sn, 8) was significantly more facile for 5 and 7 and, in all cases, condensation was inhibited in DMSO. Quantitative comparisons of equilibria and reaction rates were provided by analysis of NMR kinetic experiments, while DFT calculations on these and the analogous {NbW5} reactions provided comparative energetics and reaction profiles that are consistent with experimental observations. These results add to the fundamental understanding of proton migration in metal alkoxide hydrolysis/condensation and related reactions at metal oxide surfaces.
Author(s): Lebbie D, Izuagie T, Pascual-Borras M, Kandasamy B, Wills C, Waddell PG, Horrocks BR, Errington RJ
Publication type: Article
Publication status: Published
Journal: Inorganic Chemistry
Year: 2025
Volume: 649
Issue: 5
Pages: 2379–2393
Print publication date: 29/01/2025
Online publication date: 29/01/2025
Acceptance date: 22/01/2025
Date deposited: 28/01/2025
ISSN (print): 0020-1669
ISSN (electronic): 1520-510X
Publisher: American Chemical Society
URL: https://doi.org/10.1021/acs.inorgchem.4c04636
DOI: 10.1021/acs.inorgchem.4c04636
Data Access Statement: CCDC 2389467-39 2389468 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, by emailing data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge
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