Effect of aryl substituents on the rate of dark decolorization of photochromic spirochromenes of the indoline series

The introduction of aryl substituents in the 3 and 7 positions of the indoline spirochromene molecule gives rise to a certain amount of slowing down of dark decolorization in toluene and dioxane; similar changes in the 5, 6, and 8 positions do not change the rate appreciably.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 79–81, January, 1977.     

Existence of a photodecolorization reaction of the colored form of spiropyrans under the influence of initiating UV irradiation

The kinetics of photochromic transformations of spiropyrans of the indole series with various substituents in the 1 and 5 positions were studied. The existence of a photodecolorization reaction under the influence of activating UV light was proved, and the effect of substituents on the quantum yields of the photocoloration and photodecolorization reactions was studied.     

Electronic absorption spectra of merocyanine forms of spiropyrans

A simple method is proposed for the measurement of the absorption spectra in the visible and UV regions of photocolored solutions of spiropyrans, formed by the action of constant lowintensity UV irradiation, and for the construction, on the basis of these data, of the absorption spectra of the merocyanine forms of spiropyrans. The absorption spectra of the merocyanine forms of two spiropyrans in various solvents are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1534–1538, November, 1972.     

Synthesis and photochromic properties of indolinospirochromenes with electron-donor substituents in the indoline part of the molecule

1,3,3-Trimethylspiro(indoline-2,2'-[2H]chromenes) with CH₃ and CH₃O groups in the 4–7 positions and NO₂ and CH₃O groups in the 6 and 8 positions were obtained by the reaction of 4,6-, 4,7-, 5,6-, and 6,7-dimethoxy- and 4-methyl-7-methoxy-2-methyleneindolines and 1,3,3,4,5,6,7-heptamethyl-2-methyleneindoline with 3- and 5-nitrosalicylaldehydes and their derivatives. Most of the compounds have photochromic properties. The introduction of electron-donor groups into the indoline fragment of the spirochromene molecules changes the rate of the dark reaction within the limits of one order of magnitude and has a small effect on the position of the long-wave absorption band of the photomerocyanine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1220–1224, September, 1982.     

1-octadecyl- and 3,3-diphenyl-substituted photochromic indolinospirochromenes

A number of photochromic indolinospirochromenes that contain an octadecyl substituent in the 1 position were synthesized. The introduction of an octadecyl group in place of a methyl group increases the stability of the merocyanine form in solution but does not change its spectral characteristics. On the other hand, the introduction of phenyl groups in place of methyl groups in the 3 position does not change the stability of the merocyanine but gives rise to a bathochromic shift of the long-wave absorption band.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 51–54, January, 1980.     

Reaction of the fischer base with nitro- and bromo-substituted o-hydroxycinnamaldehydes

The Fischer base reacts with -ethyl-5-nitro-, 5-bromo-, and 3,5-dibromo-2-hydroxy-cinnamaldehydes to give bisindoline spirochromans, with 3-bromo-5-nitro-2-hydroxy-cinnamaldehyde to give a mixture of a spirochroman and a monoindoline merocyanine, and with 3,5-dinitro-2-hydroxycinnamaldehyde to give only a merocyanine. The monoindoline merocyanines obtained do not display a tendency to undergo intramolecular cyclization to give spiro-2H-oxocines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 775–778, June, 1984.     

Synthesis and spectral characteristics of photochromic 6- and 8-phenyl- substituted indoline spirochromenes

Two photochromic indoline spirochromenes were synthesized. The introduction of a phenyl group into the 6 or 8 position causes a bathochromic shift of the bands in the electronic absorption spectrum of the merocyanine form.     

Photochromic properties of some N-substituted 3,3-dimethyl-6′-nitroindoline-2-spiro-2′-2H-chromenes

A number of photochromic 1-carbethoxymethyl-3,3-dimethyl-6-nitroindoline-2-spiro-2-2H-chromenes were synthesized. The introduction of a carbethoxymethyl substituent at the nitrogen atom instead of a methyl group somewhat increases the rate of dark decolorization of the photomerocyanines without appreciably affecting the spectral characteristics. The results are compared with the analogous spectral-kinetic characteristics of 1-phenyl-substituted compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1640–1644, December, 1977.