Journal ArticleDOI
Aromaticity‐Controlled Thermal Stability of Photochromic Systems Based on a Six‐Membered Ring as Ethene Bridges: Photochemical and Kinetic Studies
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TLDR
Three ethene bridges with different degrees of aromaticity can provide a systematic comparison of the thermal stability evolution for their corresponding closed forms (c-BTE-NA, c-BTA, and c-BTTA).Abstract:
Three photochromic compounds--2-butyl-5,6-bis[5-(4-methoxyphenyl)-2-methylthiophen-3-yl]-1 H-benzo[de]isoquinoline-1,3(2 H)-dione (BTE-NA), 4,5-bis[5-(4-methoxyphenyl)-2-methylthiophen-3-yl]benzo[c][1,2,5]thiadiazole (BTA), and BTTA, which contain naphthalimide, benzothiadiazole, and benzobisthiadiazole as six-membered ethene bridges with different aromaticities--were systematically studied in solution, sol-gel, and single-crystal states. They exhibit typical photochromic performance with considerably high cyclization quantum yields. BTE-NA, BTA, and BTTA form a typical donor-π-acceptor (D-π-A) system with significant intramolecular charge transfer (ICT) between HOMO and LUMO upon excitation, thus realizing the fluorescence modulation by both photochromism and solvatochromism. The three ethene bridges with different degrees of aromaticity can provide a systematic comparison of the thermal stability evolution for their corresponding closed forms (c-BTE-NA, c-BTA, and c-BTTA). c-BTE-NA shows first-order decay in various solvents from cyclohexane to acetonitrile. c-BTA only shows first-order decay in polar solvents such as chloroform, whereas it is stable in nonpolar solvents like toluene. In contrast, the less aromatic property of BTTA gives rise to its unprecedented thermal stability in various solvents even at elevated temperatures in toluene (328 K). Moreover, the small energy barrier between the parallel and antiparallel conformers allows the full conversion from BTTA to c-BTTA. In well-ordered crystal states, all three compounds adopt a parallel conformation. Interestingly, BTTA forms a twin crystal of asymmetric nature with interactions between the electron-rich oxygen atom of the methoxy group and the carbon atom of the electron-deficient benzobisthiadiazole moiety. This work contributes to the understanding of aromaticity-controlled thermal stability of photochromic systems based on a six-membered ring as an ethene bridge, and a broadening of the novel building blocks for photochromic bisthienylethene systems.read more
Citations
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Journal ArticleDOI
Reversible photochromic system based on rhodamine B salicylaldehyde hydrazone metal complex.
TL;DR: Rhodamine B salicylaldehyde hydrazone metal complex was found to undergo intramolecular ring-open reactions upon UV irradiation, which led to a distinct color and fluorescence change both in solution and in solid matrix, and the thermal bleaching rate was tunable by using different metal ions, temperatures, solvents, and chemical substitutions.
Journal ArticleDOI
Separation of Photoactive Conformers Based on Hindered Diarylethenes: Efficient Modulation in Photocyclization Quantum Yields
TL;DR: The benzobis(thiadiazole)-bridged diarylethene system provides an efficient approach to realize extremely high photocyclization quantum yields by both separating completely pure anti-parallel conformer and suppressing intramolecular charge transfer (ICT).
Journal ArticleDOI
Photochromism of asymmetrical diarylethenes with a pyrrole unit: effects of aromatic stabilization energies of aryl rings.
Gang Liu,Shouzhi Pu,Renjie Wang +2 more
TL;DR: Four novel asymmetrical diarylethenes with a pyrrole and a variable aryl unit have been synthesized and Experimental results showed that their thermal stability as well as cyclization quantum yield, photoconversion ratio, fluorescence modulation efficiency, and fatigue resistance exhibited a strong correlation with ASE.
Journal ArticleDOI
Aromaticity-Controlled Energy Storage Capacity of the Dihydroazulene-Vinylheptafulvene Photochromic System.
Anders B. Skov,Søren Lindbæk Broman,Anders S. Gertsen,Jonas Elm,Martyn Jevric,Martina Cacciarini,Martina Cacciarini,Anders Kadziola,Kurt V. Mikkelsen,Mogens Brøndsted Nielsen +9 more
TL;DR: Efforts to tune the dihydroazulene/vinylheptafulvene (DHA/VHF) couple through loss/gain of aromaticity are presented and it is predicted that by removing one of the two CN groups at C-1 of the aromatic DHA, the heat storage capacity will be further increased, as will the life-time of the VHF.
Journal ArticleDOI
Turning On Solid-State Luminescence by Phototriggered Subtle Molecular Conformation Variations.
Weijun Zhao,Zhiyang Liu,Jie Yu,Xuefeng Lu,Jacky W. Y. Lam,Jinyan Sun,Zikai He,Huili Ma,Ben Zhong Tang +8 more
TL;DR: A new PRL material, TPE-4N, that features sensitive and reversible fluorescence switching is reported, and a uniform thin-film with such fascinating PRL properties allows high-tech applications in invisible anti-counterfeiting and dynamic optical data storage with micro-resolution.
References
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Organic D-A-π-A Solar Cell Sensitizers with Improved Stability and Spectral Response
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Journal ArticleDOI
Polyphenylene-Based Materials for Organic Photovoltaics
TL;DR: C Chen Li studied chemistry and completed his Master’s thesis under the supervision of Professor He Tian at the East China University of Science and Technology in 2003 and joined the group of Professor Klaus Müllen at the Max Planck Institute for Polymer Research to work on functional rylene dyes for dye-sensitized solar cells.