Substitution Effect on the Coloration Quantum Yield of a Photochromic Bisbenzothienylethene

Uchida, Kôji; Tsuchida, Eriko; Aoi, Yoshifumi; Nakamura, Shinichiro; Irie, Masahiro

doi:10.1246/cl.1999.63

Cited by 169 publications

(152 citation statements)

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“…The photochromic properties of 1 and 2 in hexane and methanol are summarized in Table 1. The quantum yields of the photochromic reaction were evaluated by using a standard procedure with 1,2-bis[2-methylbenzo[b]thiophen-3-yl]perfluorocyclopentene [19] as a reference compound.…”

Section: Resultsmentioning

confidence: 99%

“…The C7···C10 distances observed in crystals 1 a-MeOH and 2 a-MeOH are both below www.chemeurj.org 4 , which is short enough for single-crystalline photochromism. [19] On the other hand, the geometry of 1 a in the crystal from hexane is apparently unsuitable for the photocyclization reaction (Figure 4 b). The weak hydrogen bonding between (C8)ÀH and N2 (about 2.4 ) stabilizes the nonreactive I form (Scheme 1), which was also suggested by the 1 H NMR spectroscopic study at low temperature.…”

Section: Resultsmentioning

confidence: 99%

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Regulation of Folding and Photochromic Reactivity of Terarylenes through a Host–Guest Interaction

Nakashima

Fujii

Kawai

2011

Chemistry A European J

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The photochromic reactivity of terarylenes is integrated with molecular folding that is controlled through a host–guest interaction. A thieno[3, 2,b]pyridine unit is introduced into a photochromic terarylene structure as an aryl unit to form a guest‐interacting site. Thienopyridine‐containing terarylenes showed solvent‐dependent photochromic reactivity in solution. A terarylene moiety that contains two thienopyridyl units showed significantly high photocoloration reactivity as high as 88 % of photocyclization quantum yield in methanol, whereas that value was only 24 % in hexane. A temperature‐dependent 1H NMR spectroscopic study in different solvents indicated an interconversion between photochromic‐reactive and unreactive conformations. In methanol, the intermolecular interaction between terarylene species and the solvent molecule slows the rate of interconversion and increases the population of the photochromic‐active form, whereas the unreactive conformation is dominant in hexane. Crystal‐structural studies demonstrated the perfect regulation of molecular folding between a photochromic‐active form and an unreactive conformation by changing the solvents for recrystallization. Single crystals prepared from solutions in methanol showed reversible photochromic reactivity, whereas recrystallization from solutions in hexane did not show this reactivity. X‐ray crystallographic studies of single crystals from solutions in methanol demonstrated that the photochromic molecules bind a solvent methanol molecule at the guest‐interacting site to regulate the molecular conformation into a photochromic‐active form in collaboration with specific intramolecular interactions, whereas crystals from solutions in hexane possess the photochromic‐unreactive conformation.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Regulation of Folding and Photochromic Reactivity of Terarylenes through a Host–Guest Interaction

Nakashima

Fujii

Kawai

2011

Chemistry A European J

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“…Thus, the ratio of the antiparallel conformation has to be increased e.g. by introducing bulky isopropyl substituents at the 2-and 2'-positions of the benzothiophene rings to increase the photocyclization quantum yield [68,148]. Alternatively, the ratio of the antiparallel conformation can be increased upon inclusion in confined space, e.g.…”

Section: Photochromic Conjugatesmentioning

confidence: 99%

Photoswitches: Key molecules for subdiffraction‐resolution fluorescence imaging and molecular quantification

Heilemann

Dedecker

Hofkens

et al. 2009

Laser & Photonics Reviews

248

191

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Optical microscopes, often referred to as 'light microscopes', use visible light and a system of lenses to provide us with magnified images of small samples. Combined with highly sensitive fluorescence detection techniques and efficient fluorescent probes they allow the non-invasive 3D study of subcellular structures even in living cells or tissue. However, optical microscopes are subject to the diffraction barrier of light which imposes an optical resolution limit of approximately 200 nm in the imaging plane. In the recent past new techniques emerged that break the diffraction barrier and enable structural investigations with so far unmatched resolution. They are all based on the selective switching of fluorophores between a fluorescent and a nonfluorescent state and are therefore generalized under the denotation "Photoswitching Microscopy". Here we review recent progress in subdiffraction-resolution fluorescence imaging microscopy using various photoswitchable fluorophores and strategies. Special emphasis will be placed on the design and development of photoswitches and the requirements photoswitches have to fulfill for successful use in photoswitching microscopy. Moreover, we demonstrate how photoswitches can be used advantageously for molecular quantification, i.e. the determination of densities and absolute numbers of proteins located in specific subcellular compartments and discuss concepts how standard organic fluorophores can be used successfully for photoswitching microscopy.All subdiffraction-resolution fluorescence imaging methods are based on the separation of fluorescence emission in time. Thus, they critically depend on the availability of photoswitches, i.e. molecules that can be switched between a fluorescent and nonfluorescent state upon irradiation with light with high reliability. Here we describe the development and operation methods of diverse photoswitches and their application for superresolution fluorescence imaging and molecular quantification.

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“…48,50,57,58 The open-ring 7a isomer converts to the closed-ring 7b isomer upon irradiation with UV light. The colorless n-hexane solution containing 7a ( max = 258 nm, ¾ = 1.5 © 10 4 M ¹1 cm…”

Section: ¹5mentioning

confidence: 99%

Photoswitchable Turn-on Mode Fluorescent Diarylethenes: Strategies for Controlling the Switching Response

Irie

Morimoto

2017

Bulletin of the Chemical Society of Japan

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University. He has been conducting research on molecular photoswitches for the last 40 years. In the middle of the 1980s he discovered thermally irreversible and fatigue resistant photochromic diarylethenes. His current interests focus on the development of light-driven molecular-crystal actuators and turn-on mode fluorescent diarylethenes for super-resolution fluorescence microscopies. Masakazu Morimoto AbstractA new type of photoswitchable fluorescent diarylethenes, which have no fluorophore unit but emit strong fluorescence (¯f ³ 0.9) in the closed-ring isomers, has been developed. They are sulfone derivatives of 1,2-bis(2-alkyl-4-methyl-5-phenyl-3-thienyl)perfluorocyclopentenes and 1,2-bis(2-alkyl-1-benzothiophen-3-yl)perfluorocyclopentenes. By chemical modifications of the structures their switching response was tuned to meet the requirements for super-resolution fluorescence microscopies. The water-soluble derivatives have been successfully applied to acquire super-resolution bioimages using a single-wavelength visible beam.Fluorescence is the most convenient tool to detect small amounts of molecules.1 Even single molecules can be detected using fluorescence owing to remarkable progress of optical detection techniques. 24 Various types of highly fluorescent chromophores have been synthesized and widely applied in materials and life sciences, such as microanalysis and bioimaging.59 Their application is expected to be further extended when an additional switching property is provided to the chromophores. 10 The changes in fluorescence spectra and/or intensity by external stimuli, such as chemicals, electrons (or holes) or photons, are ingeniously adopted for analysis and imaging. When the fluorescence is photoactivated or switched on and off upon photoirradiation, the fluorescence modulation offers the opportunities to monitor diffusion processes in real time, 1113 store optical information in memory media, 1420 and increase the resolution in imaging. 10,2023 There are two types of fluorescence switching molecules, photoactivatable and photoswitchable ones. The photoactivatable molecules irreversibly switch from non-fluorescent to fluorescent states, while photoswitchable ones undergo reversible switching between fluorescent and non-fluorescent states. The reversibly photoswitchable molecules can be designed and constructed by integrating both photochromic and fluorescent chromophores in a molecule. 1420 Based on this strategy

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Substitution Effect on the Coloration Quantum Yield of a Photochromic Bisbenzothienylethene

Abstract: Introduction of isopropyl substituents to 2 and 2′ positions of benzothiophene rings of bis(1-benzothiophen-3-yl)hexa-fluorocyclopentene increased the population of anti-parallel conformation, and enhanced the quantum yield of the cyclization reaction.

Cited by 169 publications

References 7 publications

Regulation of Folding and Photochromic Reactivity of Terarylenes through a Host–Guest Interaction

Regulation of Folding and Photochromic Reactivity of Terarylenes through a Host–Guest Interaction

Photoswitches: Key molecules for subdiffraction‐resolution fluorescence imaging and molecular quantification

Photoswitchable Turn-on Mode Fluorescent Diarylethenes: Strategies for Controlling the Switching Response

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