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dc.contributor.authorXie, Z.en_US
dc.contributor.authorHenderson, E. J.en_US
dc.contributor.authorDag, Ö.en_US
dc.contributor.authorWang, W.en_US
dc.contributor.authorLofgreen, J. E.en_US
dc.contributor.authorKübel, C.en_US
dc.contributor.authorScherer, T.en_US
dc.contributor.authorBrodersen, P. M.en_US
dc.contributor.authorGu, Zhong-Zeen_US
dc.contributor.authorOzin, G. A.en_US
dc.date.accessioned2016-02-08T09:53:36Z
dc.date.available2016-02-08T09:53:36Z
dc.date.issued2011en_US
dc.identifier.issn0002-7863
dc.identifier.urihttp://hdl.handle.net/11693/21961
dc.description.abstractThere has always been a fascination with "impossible" compounds, ones that do not break any rules of chemical bonding or valence but whose structures are unstable and do not exist. This instability can usually be rationalized in terms of chemical or physical restrictions associated with valence electron shells, multiple bonding, oxidation states, catenation, and the inert pair effect. In the pursuit of these "impossible" materials, appropriate conditions have sometimes been found to overcome these instabilities and synthesize missing compounds, yet for others these tricks have yet to be uncovered and the materials remain elusive. In the scientifically and technologically important field of periodic mesoporous silicas (PMS), one such "impossible" material is periodic mesoporous hydridosilica (meso-HSiO1.5). It is the archetype of a completely interrupted silica open framework material: its pore walls are comprised of a three-connected three-dimensional network that should be so thermodynamically unstable that any mesopores present would immediately collapse upon removal of the mesopore template. In this study we show that meso-HSiO1.5 can be synthesized by template-directed self-assembly of HSi(OEt)3 under aqueous acid-catalyzed conditions and after template extraction remains stable to 300 °C. Above this temperature, bond redistribution reactions initiate a metamorphic transformation which eventually yields periodic mesoporous nanocrystalline silicon-silica, meso-ncSi/SiO2, a nanocomposite material in which brightly photoluminescent silicon nanocrystallites are embedded within a silica matrix throughout the mesostructure. The integration of the properties of silicon nanocrystallinity with silica mesoporosity provides a wealth of new opportunities for emerging nanotechnologies.en_US
dc.language.isoEnglishen_US
dc.source.titleJournal of the American Chemical Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1021/ja111495xen_US
dc.subjectAqueous acidsen_US
dc.subjectChemical bondingsen_US
dc.subjectDirected self-assemblyen_US
dc.subjectMeso-poresen_US
dc.subjectMesoporeen_US
dc.subjectMesoporosityen_US
dc.subjectMesoporousen_US
dc.subjectMesoporous Silicaen_US
dc.subjectMesostructuresen_US
dc.subjectMetamorphic transformationsen_US
dc.subjectMultiple bondingen_US
dc.subjectNanocomposite materialsen_US
dc.subjectNanocrystallinityen_US
dc.subjectNew opportunitiesen_US
dc.subjectOpen-framework materialsen_US
dc.subjectOxidation stateen_US
dc.subjectPhysical restrictionen_US
dc.subjectPore wallen_US
dc.subjectRedistribution reactionsen_US
dc.subjectSilica compositesen_US
dc.subjectSilica matrixen_US
dc.subjectSilicon nanocrystallitesen_US
dc.subjectTemplate extractionen_US
dc.subjectThermal transformationsen_US
dc.subjectThree-dimensional networksen_US
dc.subjectValence electronen_US
dc.titlePeriodic mesoporous hydridosilica-synthesis of an "impossible" material and its thermal transformation into brightly photoluminescent periodic mesoporous nanocrystal silicon-silica compositeen_US
dc.typeArticleen_US
dc.departmentDepartment of Chemistryen_US
dc.citation.spage5094en_US
dc.citation.epage5102en_US
dc.citation.volumeNumber133en_US
dc.citation.issueNumber13en_US
dc.identifier.doi10.1021/ja111495xen_US
dc.identifier.eissn1520-5126


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