Synthesis and photochromic properties of perfluoroalkyl and trifluoromethylsulphonyl substituted indoline spirochromenes

Abstract

A number of new perfluoroalkyl and trifluoromethylsulphonyl substituted indoline spirochromenes have been synthesized. It was shown that the introduction of trifluoromethylsulphonyl or heptafluoropropyl groups into the chromene moiety of the indoline spirochromene molecule results in their ability to undergo photochromic conversions. The dyes were examined by spectrophotometry and the rate constants were determined for the fading reaction. Some correlations of the rate constants with the electron withdrawing properties of the substituents were observed.