Spiro indoline-naphthopyrans

A. Kellmann, F. Tfibel, E. Pottier, R. Guglielmetti, A. Samat, and M. Rajzmann, Effect of nitro substituents on the photochromism of some spiro[indoline-naphthopyrans] under laser excitation, J. Photochem. Photobiol. A Chem., 76, 77—82 (1993). 

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... 

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... 

Activation energies for the ring opening and for the ring closure of spiro[indoline-benzopyrans] 67-76, spiro[indoline-naphthopyrans] 77-79, and spiro[oxaindane-pyrans] 4, 80 and 81 have been studied in amorphous vitreous state.50... 

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