Spiro indoline-naphthoxazines

Up to 1993, the major products from photodegradation of spiro [indoline-naphthoxazines] had not been reported. In 1993, a comparative study of the products from the photodegradation of 8-CH30-6-N02-BIPS(ll), spiro [indoline-naphthopyran] 4, and spiro [indoline-naphthoxazine] 8 was reported by Gugliel-metti and co-workers.37... 

A. Kellmann, F. Tfibel, and R. Guglielmetti, Effect of substituents on the photochromism of a spiro(indoline-naphthoxazine) under laser excitation, J. Photochem. Photobiol. A 91, 131-136 (1995). 

This chapter, far from being exhaustive, is aimed at outlining the properties of the radical ions and of the free radicals derived from photochromic compounds independently of whether or not these paramagnetic species are involved in the photochromic process itself. In particular, it will deal with the EPR of dihydro-and dialkyldipyridyl radical cations (viologens) and of the radical anions of a variety of nitro-substituted spirofmdoline-benzopyrans], spiro[indoline-naphtho-pyrans], and spiro[indoline-naphthoxazines] as well as their triphenylgermyloxy nitroxides and with the triplet spectra observed upon irradiation of 2,2,4,4-tetrachloro-1 -keto-1,4-dihydronaphthalene. 

P. Lareginie, A. Samat, and R. Guglielmetti, Structure-visible absorption relationship in the photochromic spiro(indoline-naphthoxazine) series, J. Phys. Org. Chem. 9, 262-264 (1996). 

E. Pottier, M. Sergent, R. Phan Tan Luu, and R. Guglielmetti, Synthese de quelques spiro [indoline-naphthoxazines] et spiro[indolinepyridobenzoxazines]-photochromiques, Bull. Soc. Chim. Belg. 101, 719-739 (1992). 

P. Lareginie, E. Zaballos-Garcia, V. A. Lokshin, A. Samat, R. Guglielmetti, S. Aldoshin, and O. S. Filipenko, Synthesis of photochromic 6 -sulfanyl substituted spiro[indoline-naphthoxazines],... 

Most of the known spirofindoline-benzoxazines] and spiro[indoline-naphthoxazines] are certainly thermochromic, but the examples of thermochromic behavior described in the literature for spiro[indoline-naphthoxazines] (29— 35),7 14-18 31 32 spirofindoline-phenanthroxazines] (36 and 37).14 17 spiro[indo-line-phenanthrolinooxazines] (38),13 and spiro[oxazepine-naphthoxazines] (39)33 are few in number. 

Recent calculations performed on the spiro[indoline-naphthoxazine] 29 at the semiempirical PM3 level40 (TS option for determining the transition state and IRC option to connect the transition state to the spiro form and the most stable open form, respectively) have confirmed that the rate-determining step in the reaction path is the C-0 bond breaking. 

For photochromic compounds, the eMC values can be estimated at low temperature after flash photolysis of the SP form. Indeed, the rate of thermal decay of the colored form decreases rapidly as the temperature is lowered and can be completely stopped. For example, at a temperature of - 70°C, Chu7 estimated eMc = 7.3 x 104 dm3 mol-1 cm-1 for the spiro[indoline-naphthoxazine] 29. 

Fedorova, O.A., Gromov, S.P., Pershina, Y.V., Sergeev, S.S., Strokach, Y.P., Barachevsky, V.A., Alfimov, M.V., Pepe, G., Samat, A., Guglielmetti, R. (2000) Novel azacrown ether-containing spiro[indoline-2,3,-naphthoxazines] design, synthesis and cation-dependent photochromism, J. Chem. Soc., Perkin Trans. 2, 563-571. 

J. Hobley and F. Wilkinson, Photochromism of naphthoxazine-spiro-indolines by direct excitation and... 

F. Wilkinson, D. R. Worrall, J. Hobley, L. Jansen and S. L. Williams, Picosecond time-resolved spectroscopy of the photocolouration reaction of photochromic naphthoxazine-spiro-indolines, J. Chem. Soc. Faraday Trans. 92, 1331-1336 (1996). 

Spirofindoline-benzopyrans], spiro[indoline-naphthopyrans], and spiro[indo-line-naphthoxazines] can rather readily undergo electron-transfer processes in either direction i.e they can be readily oxidized and reduced. Because the presence of nitro groups in their molecular framework normally enhances the photochromaticity of these compounds, several combined electrochemical and EPR studies have been carried out on a variety of mono- and dinitro-substituted spiroindolinic photochromes.52 56-60... 

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