- Opening a spiropyran ring by way of an exciplex intermediate
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(Chemical Equation Presented) A molecular dyad has been synthesized in which the main chromophore is a 1,4-diethynylated benzene residue terminated with pyrene moieties, this latter unit acting as a single chromophore. A spiropyran group has been condense
- Benniston, Andrew C.,Harriman, Anthony,Howell, Sarah L.,Li, Peiyi,Lydon, Donocadh P.
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- Heterometallic Actinide-Containing Photoresponsive Metal-Organic Frameworks: Dynamic and Static Tuning of Electronic Properties
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Acquiring fundamental knowledge of properties of actinide-based materials is a necessary step to create new possibilities for addressing the current challenges in the nuclear energy and nuclear waste sectors. In this report, we established a photophysics–electronics correlation for actinide-containing metal-organic frameworks (An-MOFs) as a function of excitation wavelength, for the first time. A stepwise approach for dynamically modulating electronic properties was applied for the first time towards actinide-based heterometallic MOFs through integration of photochromic linkers. Optical cycling, modeling of density of states near the Fermi edge, conductivity measurements, and photoisomerization kinetics were employed to shed light on the process of tailoring optoelectronic properties of An-MOFs. Furthermore, the first photochromic MOF-based field-effect transistor, in which the field-effect response could be changed through light exposure, was constructed. As a demonstration, the change in current upon light exposure was sufficient to operate a two-LED fail-safe indicator circuit.
- Martin, Corey R.,Leith, Gabrielle A.,Kittikhunnatham, Preecha,Park, Kyoung Chul,Ejegbavwo, Otega A.,Mathur, Abhijai,Callahan, Cameron R.,Desmond, Shelby L.,Keener, Myles R.,Ahmed, Fiaz,Pandey, Shubham,Smith, Mark D.,Phillpot, Simon R.,Greytak, Andrew B.,Shustova, Natalia B.
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p. 8072 - 8080
(2021/03/01)
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- Flipping the Switch: Fast Photoisomerization in a Confined Environment
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Stimuli-responsive materials are vital for addressing emerging demands in the advanced technology sector as well as current industrial challenges. Here, we report for the first time that coordinative integration of photoresponsive building blocks possessing photochromic spiropyran and diarylethene moieties within a rigid scaffold of metal-organic frameworks (MOFs) could control photophysics, in particular, cycloreversion kinetics, with a level of control that is not accessible in the solid state or solution. On the series of photoactive materials, we demonstrated for the first time that photoisomerization rates of photochromic compounds could be tuned within almost 2 orders of magnitude. Moreover, cycloreversion rates of photoresponsive derivatives could be modulated as a function of the framework structure. Furthermore, through MOF engineering we were able to achieve complete isomerization for coordinatively immobilized spiropyran derivatives, typically exhibiting limited photoswitching behavior in the solid state. For instance, spectroscopic analysis revealed that the novel monosubstituted spiropyran derivative grafted to the backbone of the MOF pillar exhibits a remarkable photoisomerization rate of 0.16 s-1, typical for cycloreversion in solution. We also applied the acquired fundamental principles toward mapping of changes in material properties, which could provide a pathway for monitoring material aging or structural deterioration.
- Williams, Derek E.,Martin, Corey R.,Dolgopolova, Ekaterina A.,Swifton, Anton,Godfrey, Danielle C.,Ejegbavwo, Otega A.,Pellechia, Perry J.,Smith, Mark D.,Shustova, Natalia B.
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supporting information
p. 7611 - 7622
(2018/06/06)
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- Synthesis and reactions of 1H-4,1,2-benzothiadiazines, and observations on the structure of hydrazonoyl sulphides
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Syntheses of 1-acetyl-7- and -8-bromo- and -6,8-dibromo-3-phenyl-4,1,2-benzothiadiazines establish, in conjunction with previous data, the generality of 1H-4,1,2-benzothiadiazine synthesis from appropriately substituted N′-acetyl-N′-arylbenzothiohydrazides. The corresponding 6-nitrobenzothiadiazine is also available by this route, and such cyclizations can proceed by expulsion of a nitro-group, presumably as nitrite ion. These 1H-4,1,2-benzothiadiazines undergo electrophilic substitution at positions 6 and 8, are nucleophilic at position 1, and are oxidizable at position 4 to the corresponding sulphone. X-Ray crystallographic studies of bis-[α-(2,6-dibromophenylhydrazono)benzyl] sulphide confirm the symmetrical structure of hydrazonoyl sulphides.
- Vukov, Darko J.,Gibson, Martin S.,Lee, William E.,Richardson, Mary F.
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p. 192 - 196
(2007/10/05)
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