6-Nitrospiro indoline-benzopyran

The peak reduction potential for nitrospiro[indoline-benzopyrans] 57-62... 

Photoinduced, spontaneous aggregation processes have been shown to occur when indolinobenzopyrans are irradiated in aliphatic solvents. The aggregates which are globular in appearance, consist of submicron cores of crystalline materials with an amorphous exterior and are termed "quasicrystals" (L-3). Spectroscopic studies by Krongauz and coworkers (1) indicate that the composition of the cores are AnB (n=2,3) and the amorphous exteriors AB. The most stable quasicrystals have been derived from 1-(/ -metha-crolyloxyethyl)-3,3 dimethyl-61-nitrospiro- (indoline-2,2 —[2H-1 ] benzopyran (SP-A) and its associated merocyanine form (SP-B). 

When rare-earth-metal ions such as Eu and Tb are bound to polyelectrolyte membranes such as poly(sodium acrylate) and poly(sodium ethene-sulphonate) their fluorescence intensities are considerably enhanced this is associated with the formation of asymmetric bonds between the rare-earth ions and the acrylate/S03 groups in the polymers. This was confirmed by the addition of EDTA to the Tb -poly(sodium acrylate) complex which, because of its preferential binding to the polymer, displaced Tb ions and resulted in reduced fluorescence of the latter. Stokes shifts of fluorescent dyes in different polymer systems have been related more to mobility effects in the polymer than polarity,and the fluorescence of hydrolysed aspirin has been found to be affected by the nature of different polymer supports.The luminescence properties of cis-(2,2 -bipyridyl)ruthenium(ii) complexes have been found to be influenced by binding the complex to a polymer matrix,as have the luminescence properties of flavones and l-octadecyl-3,3-dimethyl-6 -nitrospiro(indoline-2,2 -2H-benzopyran). Other studies of interest in-... 

Photo-control of the enzymic activity has been achieved by attaching a photo-chromic spiropyran to a-amylase. The derivative obtained when Bacillus subtilis a-amylase reacted with l-(2-carboxyethyl)-3,3-dimethyl-6 -nitrospiro[indoline-2,2 -2//-benzopyran] anhydride exhibited a reversible photochromism in aqueous solution it is yellow in the dark and colourless under u.v.-irradiation. The enzymic activity of the colourless derivative is much less than that of the coloured derivative, due, most probably, to a change in affinity for the substrate (amylose). 

Autonomous underwater vehicle Improvised Munitions Black Book Vol. 1 l/,3-Dihydro-l/-(2-carboxyethyl)-3,3-dimethyl-6-nitrospiro [2H-1 -benzopyran-2,2/-(2H)-indoline]... 

Figure 4. Dependence of log(D7 /Dri) (i.e., the ratio of the optical density DT after n flashes to the optical density DTl after the first flash) on n for l, 3, 3 -trimethyl-8-methoxy-6-nitrospiro[2//-l-benzopyran-2,2 -indoline] (11). Deviation ftom linearity is more pronounced for aerated toluene or benzene solutions than for the corresponding deaerated solutions. (Reprinted from Ref. 28 with permission of Editions Scientifiques et Medicales Elsevier.)...

K. Sh. Karaev and N. G. Furmanova, On crystal and molecular structure of photochromic spiropyran l-benzyl-3,3-dimethyl-6 -nitrospiro([27/-l]-benzopyran-2, 2-indoline). Zh. Strukt. Khim. 25, 185— 188 (1984). 

Labsky et have studied the photochromic behaviour of spiropyrans. For example, r,3, 3 -trimethyl-6-nitrospiro(2/f-l-benzopyran-2,2 -indoline) undergoes the configurational change shown in Scheme 12. 

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