- Ultrafast bidirectional photoswitching of a spiropyran
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We report on bidirectional photochemical switching of 6,8-dinitro-1′, 3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indoline] (6,8-dinitro-BIPS) between the ring-closed spiropyran and the ring-open merocyanine form. This is studied by femtosecond three-color
- Buback, Johannes,Kullmann, Martin,Langhojer, Florian,Nuernberger, Patrick,Schmidt, Ralf,Wuerthner, Frank,Brixner, Tobias
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Read Online
- Photo-/Baso-Chromisms and the Application of a Dual-Addressable Molecular Switch
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Two typical molecular switches of spiropyran (SP) and benzoxazine (OX) were fused by sharing an indole to achieve a new dual-addressable molecular switch (SP-OX-NO2). Through proper molecular modification with NO2, the transformation
- Liu, Danyang,Yu, Binhong,Su, Xing,Wang, Xiaojun,Zhang, Yu-Mo,Li, Minjie,Zhang, Sean Xiao-An
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p. 2838 - 2845
(2019/07/18)
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- Unusual thermo(photo)chromic properties of some mononitro- and dinitro- substituted 3′-alkyl indolospirobenzopyrans This paper is dedicated to the memory of Dr Thomas G. Nevell.
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Isomeric equilbria of dinitro-substituted indolospirobenzopyrans, possessing 3′-gem-methyl- or 3′-cyclohexyl-substitutents, have been investigated using 1H NMR spectroscopy at six temperatures, ranging from 298 K to 410 K; isomerisation processes in a methanolic solution have been monitored by spectrophotometry. For the mononitro-substituted compounds, equilibrium favoured the colourless spirocyclic isomers. Reversion of the coloured merocyanine isomers, generated by UV irradiation, followed first-order kinetics. For the dinitro-substituted compounds the coloured merocyanine isomers predominated. Following decolourisation by visible light photoirradiation, reversion towards the merocyanine structures were particularly slow, absorbances unusually increasing sigmoidally. UV. spectral observations for the gem-methyl- 1 and 3′-cyclohexyl-substituted systems 2 are qualitatively consistent with the simultaneous involvement of two relatively slow rate determining steps, possessing slowly forming and long-lived intermediates - postulated to be the oxygen protonated pyran-ring of the spirocyclic structure and TCC merocyanine isomer, the latter undergoing relatively slow isomerisation about the central β-alkenic bond to the TTC isomer.
- Abdullah, Ayse,Nevell, Thomas G.,Sammes, Peter G.,Roxburgh, Craig J.
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- Preparation of a conjugation-ready thiol responsive molecular switch
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In this work we synthesize molecular switches that are responsive to cysteine, homocysteine, and glutathione; three redox systems that make up the majority of the body's antioxidant defenses. Synthesized spiropyran isomers with conjugation-ready linkages
- Tautges, Brandon,Or, Victor,Garcia, Joel,Shaw, Jared T.,Louie, Angelique Y.
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supporting information
p. 6569 - 6573
(2015/11/09)
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- Rapid colorimetric sensing of cyanide anion in aqueous media with a spiropyran derivative containing a dinitrophenolate moiety
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A spiropyran derivative containing a dinitrophenolate moiety (2: 1′,3′,3′-trimethyl-6,8-dinitro-spiro-[2H-1-benzopyran-2, 2′-indoline]) behaves as a receptor for selective detection of cyanide anion (CN-) in aqueous media. Compound 2, when dissolved in aqueous media, spontaneously produces the spirocycle-opened merocyanine (MC) form even in dark condition. The absorption band of the MC form decreases selectively upon addition of CN-, via a nucleophilic addition of CN- to the spirocarbon of the MC form. The nucleophilic addition occurs very rapidly (within 1 min) and enables rapid and selective quantification of very low levels of CN- (>0.8 μM) by an absorption analysis.
- Shiraishi, Yasuhiro,Itoh, Masataka,Hirai, Takayuki
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supporting information; experimental part
p. 1515 - 1519
(2011/05/16)
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- Novel syntheses of spiropyran photochromatic compounds using ultrasound
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Photochromatic derivatives 1,3,3-trimethylindoline-2-spiro-2'-benzopyran, were synthesized using ultrasound as energy source (55 watt), reaction times are between 10 to 20 min, obtaining higher or slightly lower yield than the conventional reported methods.
- Torres,Vazquez,Gonzalez
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p. 105 - 110
(2007/10/02)
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- Thermo- and Photochromic Dyes: Spiro(indolinebenzopyrans) 2. - Detailed Assignment of the 1H NMR Spectra and Structural Aspects of the Closed Form of 1,3,3-Trimethylspiro(indoline-2,2'-benzopyrans)
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The proton NMR assignments for a series of 12 thermo- and photochromic 1,3,3-trimethylspiro(indoline-2,2'-benzopyrans) dyes is reported.All of the protons in the dye molecule were assigned through a combination of homonuclear decoupling experiments and correlation spectroscopy.The relative stereochemistry of the indolino gem-dimethyl groups was assigned so that, for the S-epimer, the pro-R methyl was found to resonate at 1.24 ppm while the pro-S methyl appeared at 1.37 ppm for compound 1. KEY WORDS: Thermo- and photochromic dyes, Spiro(indoline-2,2'-benzopyrans), 1H NMR assignments
- Keum, Sam-Rok,Lee, Ki-Bong,Kazmaier, Peter M.,Manderville, Richard A.,Buncel, Erwin
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p. 1128 - 1131
(2007/10/02)
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