Mechanism of Photoinduced Bending and Twisting in Crystalline Microneedles and Microribbons Composed of 9-Methylanthracene.
The solid-state photodimerization of 9-methylanthracene is used as a model system to investigate how crystal morphology and reaction dynamics affect photomechanical deformations of single microcrystals. By varying the crystallization conditions, two different crystal shapes, microneedles and microri...
| Publicado en: | Journal of the American Chemical Society Vol. 136; no. 18; pp. 6617 - 6626 |
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| Autores principales: | , , , |
| Formato: | Artículo |
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American Chemical Society
5/7/2014
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=96264201&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 96264201 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 5/7/2014 vid: 136 iid: 18 pid: 997 pub: American Chemical Society artinfo: ui: 96264201 10.1021/ja412216z ppf: 6617 ppct: 9 formats: tig: atl: Mechanism of Photoinduced Bending and Twisting in Crystalline Microneedles and Microribbons Composed of 9-Methylanthracene. aug: au: Taehyung Kim Lingchao Zhu Mueller, Leonard J. Bardeen, Christopher J. affil: Department of Chemistry, University of California, Riverside, California 92521, United States su: Microstructure Flexure Photodimerization Crystal morphology Deformations (Mechanics) Irradiation X-ray diffraction Spin-lattice relaxation sug: subj: Microstructure Flexure Photodimerization Crystal morphology Deformations (Mechanics) Irradiation X-ray diffraction Spin-lattice relaxation ab: The solid-state photodimerization of 9-methylanthracene is used as a model system to investigate how crystal morphology and reaction dynamics affect photomechanical deformations of single microcrystals. By varying the crystallization conditions, two different crystal shapes, microneedles and microribbons, are grown on a clean water surface. The microribbons twist under irradiation, while the microneedles bend. In both shapes, the maximum deformation occurs at roughly the midpoint of the reaction, while further dimerization causes the crystals return to their original shapes. Powder X-ray diffraction patterns establish that the needles and ribbons have the same crystal orientation and that the photoreaction proceeds in a crystal-to-crystal manner. NMR spin–lattice relaxation measurements are consistent with the rapid formation of large (>100 nm) dimer crystal domains. Simultaneous measurement of the needle bending and monomer fluorescence signal allows us to correlate the bending with the reaction progress. The behavior is qualitatively reproduced by a model in which the motion is driven by strain between spatially distinct reactant and product domains, also called heterometry. We consider several different mechanisms that could give rise to these spatially distinct domains. The ability to control the photoinduced crystal deformation by manipulating crystal shape and solid-state reaction kinetics suggests that photoreactive molecular crystals may be useful for generating well-defined motions on small length scales. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2014 holdings: @attributes: islocal: N |
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