20200-64-0Relevant articles and documents
Ultrafast bidirectional photoswitching of a spiropyran
Buback, Johannes,Kullmann, Martin,Langhojer, Florian,Nuernberger, Patrick,Schmidt, Ralf,Wuerthner, Frank,Brixner, Tobias
, p. 16510 - 16519 (2010)
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
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.
Abdullah, Ayse,Nevell, Thomas G.,Sammes, Peter G.,Roxburgh, Craig J.
, p. 57 - 72 (2015/06/02)
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.
Rapid colorimetric sensing of cyanide anion in aqueous media with a spiropyran derivative containing a dinitrophenolate moiety
Shiraishi, Yasuhiro,Itoh, Masataka,Hirai, Takayuki
supporting information; scheme or table, p. 1515 - 1519 (2011/05/16)
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.
