- Core-modified rubyrins containing dithienylethene moieties
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Two stable core-modified rubyrins bearing one and two dithienylethene (DTE) units (1 and 2) have been synthesized. With one "closed-form" DTE unit, 1 shows aromaticity associated with its conjugated circuit of 26 π-electrons. In contrast, rubyrin 2 containing one "open-form" DTE unit has nonaromatic properties.
- Zhou, Zhikuan,Chang, Yi,Shimizu, Soji,Mack, John,Schuett, Christian,Herges, Rainer,Shen, Zhen,Kobayashi, Nagao
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- A new class of photochromic 1,2-diarylethenes; synthesis and switching properties of bis(3-thienyl)cyclopentenes
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A novel synthetic route to diarylethenes fixed in a cyclopentene based on titanium-mediated carbonyl coupling leads to bis(3-thienyl)cyclopentenes that show photochromic behaviour similar to that of known diarylethenes.
- Lucas, Linda N.,Van Esch, Jan,Kellogg, Richard M.,Feringa, Ben L.
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- A novel approach to achieve molecular switching in solid-state driving by thermal treatment: A photochromic zinc-coordination polymer
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The molecular switching of complexes based on diarylethenes in a solid-state is their most frequently studied property. This switching becomes possible when the active carbon atoms acquire a suitable interatomic separation in the molecule. Even if the structural analysis may suggest conditions disfavouring the occurrence of such switching, it may still be enabled by post-synthetic modification of the sample, like dehydration. In the present study, a novel one-dimensional coordination polymer with composition {[Zn(μ3-HA)(H2O)3]·H2O}n (I) was prepared and characterized. In its solid state, however, its thiophene rings were arranged in the non-switchable conformation yielding a C···C separation 4.148(6) ? between the active carbon atoms. After fully dehydrating the sample, this interatomic separation decreased to 3.814 ?, making it susceptible to photochromism by UV radiation.
- Almá?i, Miroslav,Walko, Martin,Bor?íková, Jana,Gyepes, Róbert
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- Reversible light-directed red, green, and blue reflection with thermal stability enabled by a self-organized helical superstructure
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Adding external, remote, and dynamic control to self-organized superstructures with desired properties is an important leap necessary in leveraging the fascinating molecular subsystems for employment in applications. Here two novel light-driven dithienylethene chiral molecular switches possessing remarkable changes in helical twisting power during photoisomerization as well as very high helical twisting powers were found to experience photochemically reversible isomerization with thermal stability in both isotropic organic solvents and anisotropic liquid crystal media. When doped into a commercially available achiral liquid crystal host, the chiral switch was able to either immediately induce an optically tunable helical superstructure or retain an achiral photoresponsive liquid crystal phase whose helical superstructure was induced and tuned reversibly upon light irradiation. Moreover, reversible light-directed red, green, and blue reflection colors with thermal stability in a single thin film were demonstrated.
- Li, Yannian,Urbas, Augustine,Li, Quan
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- Synthesis, properties, and electrochemistry of a photochromic compound based on dithienylethene and ProDOT
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The synthesis, photochromic features, and electrochemistry of a novel material based on dithienylethene (DTE) and 3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine (didecyl-ProDOT) units are described. It is noteworthy that 1,2-bis(5-(3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-2-methylthiophen-3-yl)cyclopent-1-ene can be effciently switched between open and closed states by light in both solution and in the solid poly(methyl metacrylate) (PMMA) matrix. It is also found that the emission of this novel compound can be switched on and off upon irradiation.
- Algi, Melek Pamuk,Cihaner, Atilla,Algi, Fatih
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- Switching the Photochromic Activity of Acenaphthylene Derivatives through a Tandem Nucleophile-Promoted Addition Reaction
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New acenaphthylene-based dithienylethenes have been prepared. Surprisingly they did not show photochromism. However, they readily underwent a tandem addition of a nucleophile and an electrophile, leading to a small library of dearomatized colourless analogues, which, on the contrary, were endowed with photochromic activity. In the absence of the electrophile, the intermediate obtained by C-attack readily aromatizes to give, surprisingly, a final product of direct aromatic nucleophilic substitution, which was not photochromically active.
- Lambruschini, Chiara,Banfi, Luca,Guanti, Giuseppe
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- Controlling covalent connection and disconnection with light
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The on-going need for feature miniaturization and the growing complexity of structures for use in nanotechnology demand the precise and controlled formation of covalent bonds at the molecular level. Such control requires the use of external stimuli that offer outstanding spatial, temporal, as well as energetic resolution. Thus, photoaddressable switches are excellent candidates for creating a system that allows reversible photocontrol over covalent chemical connection and disconnection. Here we show that the formation of covalent bonds between two reagents and their scission in the resulting product can be controlled exclusively by illumination with differently colored light. A furyl-substituted photoswitchable diarylethene was shown to undergo a reversible Diels-Alder reaction with maleimide to afford the corresponding Diels-Alder adduct. Our system is potentially applicable in any field already relying on the benefits of reversible Diels-Alder reactions.
- Goestl, Robert,Hecht, Stefan
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- Photostimulus-Responsive Large-Area Two-Dimensional Covalent Organic Framework Films
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Using an external stimulus to modulate the electronic structure of covalent organic frameworks (COFs) is very important because such a response will endow them with additional functions. A two-dimensional (2D) COF, constructed from a photo-responsive unit (1,2-bis(5-formyl-2-methylthien-3-yl)cyclopentene), can reversibly switch its electrical conductivity 200 times from low state (the open form) to high state (the closed form) upon irradiation with UV light and reversible with visible light. This reversible phenomenon can be monitored through a circuit containing a light-emitting diode (LED). Photoinduced ring-closing/opening reactions do not destroy the integrity of the frameworks, and both processes follow logarithmic carrier generation with time. Moreover, the correlation between COFs electronic properties and changes in photoinduced kinetics and absorption curves has been demonstrated.
- Yu, Fei,Liu, Wenbo,Li, Bang,Tian, Dan,Zuo, Jing-Lin,Zhang, Qichun
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- Light-controlled self-assembly of a dithienylethene bolaamphiphile in water
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The self-assembly of bolaamphiphiles comprised of a central photochromic dithienylethene (DTE) chromophore was investigated in aqueous media. Irradiation at 254 nm induced a conversion from the open to closed states of the DTE chromophores. Whereas, in water, irradiation produced a photostationary state of 20 : 80 (open/closed), in methanol the ratio improved to 10 : 90 (open/closed). The open → closed transition was accompanied by the formation of 1D nanofibers during incubation in darkness. This journal is
- Creemer, Cassidy,Kilic, Haydar,Lee, Kwang Soo,Parquette, Jon R.,Saracoglu, Nurullah
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- Fluorescent molecular photoswitch based on basket-shaped porphyrins
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Here we present two novel basket-shaped porphyrins bridged by photochromic diarylethene derivatives, which show significant photoswitchable fluorescent properties. Their synthesis, structures, photochromism and fluorescence characteristics were reported in detail. They are desirable for reversible light-driven fluorescent molecular switches.
- Yan, Liying,Xiong, Chaochao,Jin, Piaopiao,Luo, Qianfu
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- Synthesis and properties of tetraphenylethylene derivatived diarylethene with photochromism and aggregation-induced emission
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A series of new diarylethene compounds with both photochromism and aggregation-induced emission have been synthesized by connecting tetraphenylethene and triphenylethene to the bisthienylethene. All the four compounds exhibit good photochromism upon irradiation with alternative UV and visible light. And they are all provided with aggregation-induced emission properties in tetrahydrofuran solution with different fraction of water, non-emissive in the pure tetrahydrofuran solution but yellowish green fluorescence in the aggregate or solid state. Furthermore, the compounds connecting tetraphenylethene to the bisthienylethene were found to exhibit the stronger fluorescence emission in the aggregate or solid state than the ones connecting triphenylethene to the bisthienylethene.
- Dong, Huan,Luo, Miao,Wang, Sheng,Ma, Xiang
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- In situ Generation of Hypervalent Iodine Reagents for the Electrophilic Chlorination of Arenes
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Efficient metal-free methods for the electrophilic chlorination of arenes using PIFA and simple chlorine sources are reported. The in situ formation of PhI(Cl)OCOCF3 from PIFA and KCl is proposed, which resulted in a chlorinating species for moderately activated arenes. Moreover, the in situ formation of PhICl2 from PIFA and TMSCl resulted in an excellent approach for the chlorination of a great variety of arenes (20 examples) in high yields, even when working on a multigram scale.
- Granados, Albert,Jia, Zhiyu,del Olmo, Marc,Vallribera, Adelina
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p. 2812 - 2818
(2019/04/08)
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- Design, syntheses and photochromic properties of dithienylcyclopentene optical molecular switches
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A kind of basal diarylethene through an easy synthetic procedure was synthesized and characterized, and a Suzuki coupling reaction was frequently operated to obtain the diarylethenes derivatives with some vivid functional groups like bromo, amido and pyridine. Two methods for derivatives of these switches contain porphyrins were described. All of their spectroscopic and photochromic properties were studied and intercompared. It is indicated that the difference in electron densities of the π-conjugated system of the closed forms has effects upon the absorption maxima in visible region of UV–Vis spectra. Dithienylcyclopentenes linked to porphyrins could emit luminescence substantially that display potentials to be used in the applications of nondestructive readout upon binary data storage and smart materials.
- Yu, Chuanming,Hu, Bingcheng,Liu, Cheng,Li, Jiting
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- Switching diarylethenes reliably in both directions with visible light
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A diarylethene photoswitch was covalently connected to two small triplet sensitizer moieties in a conjugated and nonconjugated fashion and the photochromic performance of the resulting compounds was investigated. In comparison with the parent diarylethene (without sensitizers) and one featuring saturated linkages, the conjugated photoswitch offers superior fatigue resistance upon visible-light excitation due to effective triplet energy transfer from the biacetyl termini to the diarylethene core. Our design makes it possible to switch diarylethenes with visible light in both directions in a highly efficient and robust fashion based on extending π-conjugation and by-product-free ring-closure via the triplet manifold. Flipping the spin: When biacetyl triplet sensitizers were linked to a dithienylethene core in a conjugated fashion, the photoswitching performance dramatically improved. This design makes it possible to switch diarylethenes with visible light in both directions in a highly efficient and robust fashion.
- Fredrich, Sebastian,G?stl, Robert,Herder, Martin,Grubert, Lutz,Hecht, Stefan
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supporting information
p. 1208 - 1212
(2016/01/20)
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- Selective Halogenation Using an Aniline Catalyst
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Electrophilic halogenation is used to produce a wide variety of halogenated compounds. Previously reported methods have been developed mainly using a reagent-based approach. Unfortunately, a suitable "catalytic" process for halogen transfer reactions has yet to be achieved. In this study, arylamines have been found to generate an N-halo arylamine intermediate, which acts as a highly reactive but selective catalytic electrophilic halogen source. A wide variety of heteroaromatic and aromatic compounds are halogenated using commercially available N-halosuccinimides, for example, NCS, NBS, and NIS, with good to excellent yields and with very high selectivity. In the case of unactivated double bonds, allylic chlorides are obtained under chlorination conditions, whereas bromocyclization occurs for polyolefin. The reactivity of the catalyst can be tuned by varying the electronic properties of the arene moiety of catalyst.
- Samanta, Ramesh C.,Yamamoto, Hisashi
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supporting information
p. 11976 - 11979
(2015/08/18)
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- Autoamplification of molecular chirality through the induction of supramolecular chirality
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The novel concept for the autoamplification of molecular chirality, wherein the amplification proceeds through the induction of supramolecular chirality, is presented. A solution of prochiral, ring-open diarylethenes is doped with a small amount of their chiral, ring-closed counterpart. The molecules co-assemble into helical fibers through hydrogen bonding and the handedness of the fibers is biased by the chiral, ring-closed diarylethene. Photochemical ring closure of the open diarylethene yields the ring-closed product, which is enriched in the template enantiomer. There and back again: Doping a mixture of rapidly interconverting prochiral, open diarylethenes (left) with their enantiopure, closed counterparts, led to formation of gel fibers of preferred helicity (center). This supramolecular chirality was transferred to the molecular level by photochemical ring closing, thus yielding a chiral product (right) which is enriched in the enantiomer originally used as a template.
- Vandijken, Derk Jan,Beierle, John M.,Stuart, Marc C. A.,Szymanski, Wiktor,Browne, Wesley R.,Feringa, Ben L.
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supporting information
p. 5073 - 5077
(2014/05/20)
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- Synthesis and photophysical properties of thiolactone derivatives
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A class of bis-thiolactone derivatives is prepared by photo-conversion of photochromic diarylethenes with a bis (5-chloro-2-methylthiophen-3-yl) system in moderate yields (50-60%). Bis-thiolactone derivatives show fluorescence in solution with moderate fluorescent quantum yields (0.11-0.17). Reaction mechanism exhibits that the photo-conversion of diarylethenes to bis-thiolactone derivatives undergoes a two-step reaction: photocyclization and photo-oxidation.
- Liu, Huan-Huan,Chen, Yi
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p. 1872 - 1876
(2013/03/13)
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- Substituent and solvent effects on the fluorescent and photochromic properties of 2-(2-pyridyl)imidazole containing diarylethene derivatives
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Five diarylethene derivatives with 2-(2-pyridyl)imidazole as the ethene bridges (PI-BTEs) were synthesized and characterized. The structures and performances of the PI-BTEs (L1-L5) could be modified from not only the thiophene unit, but also the substituent on the imidazole nitrogen. Noteworthily, replacing the thiophene with the benzothiophene, the fatigue resistance is significantly improved, the centre absorption bands of the closed forms shift from 572 nm (L3) to 550 nm (L2), and the colours of the solutions change from pale pink in L3 to red-purple in L2. Additionally, the Stokes shift (Δν) values of L3 in various solvents display good linear relationships with the donor number (DN) of the solvents, and the solvent polarity parameter Δf.
- Peng, Xuefeng,Deng, Jian-Guo,Xu, Hai-Bing
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p. 24146 - 24153
(2013/11/19)
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- Photochemically reversible and thermally stable axially chiral diarylethene switches
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A series of dithienylcyclopentenes containing axially chiral 1,1′-binaphthyl units were successfully synthesized by a Suzuki-Miyaura protocol. All these compounds exhibited photochemically reversible isomerization with thermal stability in both organic solvent and a liquid crystal (LC) host. When doping into an achiral LC host, some of them exhibited very high helical twisting powers. Reversible reflection wavelength tuning in the visible region and LC phase switching between nematic and cholesteric upon light irradiation were demonstrated.
- Li, Yannian,Li, Quan
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supporting information
p. 4362 - 4365
(2012/10/29)
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- Sterically crowding the bridge of dithienylcyclopentenes for enhanced photoswitching performance
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Better switching: The introduction of bulky substituents into the bridge moiety of dithienylethenes led to derivatives exhibiting high photocyclization quantum yields. This novel and versatile form of substitution facilitated tuning of the switching performance without compromising on the optical and redox properties of the ring-open and ring-closed forms (see scheme). Copyright
- Goestl, Robert,Kobin, Bjoern,Grubert, Lutz,Paetzel, Michael,Hecht, Stefan
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supporting information
p. 14282 - 14285
(2013/01/15)
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- Selective photoconversion of photochromic diarylethenes and their properties
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Selective photoconversions of photochromic diarylethene derivatives has been described using diarylethene derivative 1a as a model compound. Upon irradiation with 254 nm light, 1a undergoes photocyclization to yield the ring-closed isomer 1b in the absence of oxygen, or is transformed to the thiolactone derivative 1c in the presence of oxygen (in the air), respectively. It was found that 1b can be reversed back to 1a with visible light irradiation, the ring-opening and ring-closing photoswitch can be performed in the absence of oxygen. 1c is, however, photo-inactive and cannot be reversed back to 1a with UV or visible light irradiation. It was also found that 1c shows fluorescence whereas both 1a and 1b show no fluorescence. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Liu, Huan-Huan,Chen, Yi
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p. 2223 - 2227
(2013/01/15)
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- Photoresponsive dithienylethene-urea-based organogels with "reversed" behavior
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Dithienylperhydrocyclopentene-bisurea-based low molecular weight gelators are described that function as photoresponsive organogels that show a remarkable gel-to-liquid transition upon irradiation. The two series of derivatives, with and without alkyl spacers between the urea hydrogen bonding groups and the photochromic unit, show different gelation behavior. Upon UV irradiation of the gels, a gel liquified at only 1.4% conversion of the photochromic unit. Transmission electron microscopy (TEM) shows that the gel fibres consist of thin ribbons. Semi-empirical (PM3) calculations indicate that the hydrogen bonding between the open-ring isomer (o) molecules is weak, and that formation of the closed-ring isomer (c) destabilises the hydrogen bonding further. The results indicate that a small amount of the closed-ring isomer will disrupt the intermolecular hydrogen-bonding, leading to disintegration of the gel fibre ribbons and hence reversible liquification. The Royal Society of Chemistry 2008.
- Akazawa, Masako,Uchida, Kingo,De Jong, Jaap J. D.,Areephong, Jetsuda,Stuart, Marc,Caroli, Giuseppe,Browne, Wesley R.,Feringa, Ben L.
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supporting information; experimental part
p. 1544 - 1547
(2008/10/09)
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- Syntheses of dithienylcyclopentene optical molecular switches
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Properly functionalized dithienylethenes show promise for light-induced switching processes. To prevent cis/trans isomerization from competing with conrotatory 6π-electron ring closure, the ethene segment is usually incorporated in a (perfluorinated) cyclopentene. In the present article syntheses of perhydrocyclopentene 1 and perfluorocyclopentene 2 are described, which are amenable for large-scale conversions. Both compounds have chloro substituents at the 5-position of the thiophene rings to allow further functionalization. The conversion of the chloro substituents of 1 to formyl, carboxylate, boronyl, and hydrogen groups by halogen/lithium exchange at room temperature is described, and examples are given of further elaboration of 1 and 2 by attachment, both in a symmetrical as well as unsymmetrical fashion, of additional functionality by condensation, Friedel-Crafts or Suzuki reactions. The newly prepared thienylperhydrocyclopentene derivatives show reversible photochromism if the substituents at the 5-postions allow for conjugation with the thiophene π-system. Wiley-VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2003.
- Lucas, Linda N.,De Jong, Jaap J. D.,Van Esch, Jan H.,Kellogg, Richard M.,Feringa, Ben L.
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p. 155 - 166
(2007/10/03)
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- Synthesis and photochromic properties of functional diarylethene with a 2,5-dihydrothiophene bridging unit
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(Matrix presented) A novel synthetic route to symmetric and nonsymmetric dithienylethene derivatives with a 2,5-dihydrothiophene bridging unit was described. A class of new functional photochromic compounds was prepared and showed photochromic properties similar to those of known diarylethenes.
- Chen, Yi,Zeng, De X.,Fan, Mei G.
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p. 1435 - 1437
(2007/10/03)
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- A new synthetic route to symmetrical photochromic diarylperfluorocyclopentenes
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Symmetrical and photochromic diarylperfluorocyclopentene has been prepared by reaction of 3-lithio-5-chloro-2-methylthiophene with the ethyl ester of hexafluoroglutaric acid, followed by ring closure via a McMurry coupling. Compound 7 is a versatile intermediate for the development of photochromic materials.
- Lucas, Linda N.,Van Esch, Jan,Kellogg, Richard M.,Feringa, Ben L.
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p. 1775 - 1778
(2007/10/03)
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- Biphasic Electrophilic Halogenation of Activated Aromatics and Heteroaromatics with N-Halosuccinimides Catalyzed by Perchloric Acid
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Catalytic amounts of 70percent perchloric acid (0.1 - 10, mostly 0.1 - 1, mol percent, based on substrate) initiate the regioselective halogenation of activated aromatics and heteroaromatics with N-halosuccinimide (NXS, X = Cl or Br) in two-phase solid-liquid systems (NXS/hexane or NXS/CCl4) at room temperature to give ring-halogenated products in high yields.For example, thiophene is transformed to 2-halo or 2,5-dihalo derivatives (yield 82-98percent) using 1 or 2 equiv of NXS, respectively.Unsymmetrical 2,5-dihalothiophenes are obtained in 70-82percent yield by reacting 2-halothiophenes with an appropriate NXS.The reaction of 3-bromothiophene with NBS affords 2,3-dibromothiophene in 93-99percent yield. 1,3-Dimethoxybenzene and 2,3-dimethylanisole are halogenated regiospecifically at the 4-position to give the corresponding products in 81-94percent yield.
- Goldberg, Yuri,Alper, Howard
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p. 3072 - 3075
(2007/10/02)
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- NOVEL HALOGENATION OF THIOPHENES WITH BENZENESELENINYL CHLORIDE AND ALUMINUM HALIDE
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In the presence of aluminum halide, benzeneseleninyl chloride is an efficient regioselective halogenating reagent for heterocyclic compounds such as thiophene, 2-methylthiophene, 3-methylthiophene, 2,5-dimethylthiophene, and furan.In the case of pyrrole, no halogenated product was obtained.A plausible reaction mechanism involving a positive halogen intermediate is proposed.
- Kamigata, Nobumasa,Suzuki, Takashi,Yoshida, Masato
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