Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.344, 259-263, 2000
Synthesis and spectrokinetic studies of a new family of dimethyl [2H]-chromenes: Dimethyl 6-aryl-2,2dimethyl-[2H]-chromene-7,8-dicarboxylates
The synthesis of a series of dimethyl 6-aryl-2,2-dimethyl-[2H]-chromene-7,8-dicarboxylates is described. The photochromic properties of this new family of dimethyl-[2H]-chromenes have been studied in solution, under continuous irradiation. The presence of the methoxycarbonyl groups was shown to stabilise the coloured forms. The fading rates are generally low in comparison with the standard "naked" chromenes in the same experimental conditions. This stabilisation depends on the solvent used. We could observe the presence of one permanent opened form. Moreover, it seems that the synthesised molecules have a strong resistance toward photodegradation.
Keywords:propargylic ether;dimethyl 6-aryl-2;2-dimethyl-[2H]-chromene-7;8-dicarboxylates;photochromic compounds