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dc.contributor.authorDawson, Daniel M.
dc.contributor.authorWalton, Richard I.
dc.contributor.authorWimperis, Stephen
dc.contributor.authorAshbrook, Sharon E.
dc.date.accessioned2017-02-07T17:30:19Z
dc.date.available2017-02-07T17:30:19Z
dc.date.issued2017-03-01
dc.identifier.citationDawson , D M , Walton , R I , Wimperis , S & Ashbrook , S E 2017 , ' The ambient hydration of the aluminophosphate JDF-2 to AlPO-53(A) : insights from NMR crystallography ' , Acta Crystallographica Section C Structural Chemistry , vol. C73 , no. 3 , pp. 191-201 . https://doi.org/10.1107/S2053229617000377en
dc.identifier.issn2053-2296
dc.identifier.otherPURE: 248667115
dc.identifier.otherPURE UUID: 42c0232a-8694-4784-af66-c3d37114cd3a
dc.identifier.otherScopus: 85014487752
dc.identifier.otherORCID: /0000-0002-4538-6782/work/56638914
dc.identifier.otherORCID: /0000-0002-8110-4535/work/34029107
dc.identifier.otherWOS: 000395789800009
dc.identifier.urihttp://hdl.handle.net/10023/10247
dc.descriptionThe authors would like to thank EPSRC for computational support through the Collaborative Computational Project on NMR Crystallography (CCP-NC), via EP/M022501/1 and EP/J501510/1. SEA would like to thank the Royal Society and Wolfson Foundation for a merit award. The research data (and/or materials) supporting this publication can be accessed at doi:10.17630/bad7af52-94cc-4a85-8aed-09fb761b894c.en
dc.description.abstractThe aluminophosphate (AlPO), JDF-2 is prepared hydrothermally with methylammonium hydroxide (MAH+ HO–, MAH+ = CH3NH3+), giving rise to a microporous AEN-type framework with occluded MAH+ and extra framework (Al-bound) HO–. Despite the presence of these species within its pores, JDF-2 can hydrate upon exposure to atmospheric moisture to give AlPO-53(A), an isostructural material whose crystal structure contains one molecule of H2O per formula unit. This hydration can be reversed by mild heating (such as the frictional heating from magic angle spinning). Previous work has shown good agreement between NMR parameters obtained experimentally and calculated from the (optimised) crystal structure of JDF-2. However, several discrepancies are apparent between the experimental NMR parameters for AlPO-53(A) and those calculated from the (optimised) crystal structure (e.g., four 13C resonances are observed, rather than the expected two). The unexpected resonances appear and disappear reversibly with the respective addition and removal of H2O, so clearly arise from AlPO-53(A). We investigate the ambient hydration of JDF-2 using quantitative 31P MAS NMR to follow the transformation over the course of ~3 months. The structures of JDF-2 and AlPO-53(A) are also investigated using a combination of multinuclear solid-state NMR spectroscopy to characterise the samples, and first-principles density functional theory (DFT) calculations to evaluate a range of possible structural models in terms of calculated NMR parameters and energetics. The published structure of JDF-2 is shown to be a good representation of the dehydrated material, but modification of the published structure of AlPO-53(A) is required to provide calculated NMR parameters that are in better agreement with experiment. This modification includes reorientation of all MAH+ cations and partial occupancy of the H2O sites.
dc.format.extent11
dc.language.isoeng
dc.relation.ispartofActa Crystallographica Section C Structural Chemistryen
dc.rights© 2017, International Union of Crystallography. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1107/S2053229617000377en
dc.subjectAluminophosphateen
dc.subjectAEN frameworken
dc.subjectZeolitesen
dc.subjectMicroporous materialsen
dc.subjectQD Chemistryen
dc.subjectDASen
dc.subject.lccQDen
dc.titleThe ambient hydration of the aluminophosphate JDF-2 to AlPO-53(A) : insights from NMR crystallographyen
dc.typeJournal articleen
dc.description.versionPostprinten
dc.contributor.institutionUniversity of St Andrews.School of Chemistryen
dc.contributor.institutionUniversity of St Andrews.EaSTCHEMen
dc.identifier.doihttps://doi.org/10.1107/S2053229617000377
dc.description.statusPeer revieweden
dc.date.embargoedUntil2017-02-06


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