Acid-base isomerization of hybrid molecules based on fullerene C60 and spiropyrans

The reversible acid-base isomerization of fullerene C₆₀ hybrid compounds with spiropyrans has been performed for the first time. It has been found that irradiation induces isomerization only for hybrid bearing NO₂ group in the photochromic spiropyran part, while the treatment with trifluoroacetic acid induces isomerization for compounds containing NO₂, Cl or F, i.e. irrespective of the nature of substituent in the spiropyran moiety.