Effects of metal ion complexation on the spiropyran–merocyanine interconversion: development of a thermally stable photo-switch

Spectrophotometric absorption and fluorescence measurements of spiropyrans 2 and 3 modified with chelating functionalities, in the presence of Ca2+ and Zn2+, provide evidence of a thermally stable spiropyran–merocyanine photoswitch that is modulated by the metal cations.