Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.246, 37-40, 1994
Photochromic Spiropyrans of Coumarin Series
Novel spiropyrans on the base of 4-methyl-7-hydroxy-8-formylcoumarine (I) and 7-R-4-hydroxy-3-formylcoumarine (II) are synthesized. The compounds (I) and (II) exhibit in solution respectively direct and inverse photochromic reaction. The influence of the heterene moiety and solvent polarity on spectral and photochromic properties have been studied. The indoline derivatives of (I) are also photochromic in crystal.