New Photochromic Materials

The aim of this work was the synthesis and study of photochromic compounds with new properties. Five dithienylethene type compounds (1a-3a and 1b-2b) were synthesized and studied. They can reversibly interconvert between two thermally stable forms, an open and a closed one, by using light of different wavelengths as triggers. Compounds 2 and 3 represent oligothiophenes endowed with a photoactivated switch and in view of their potential use as switched oligothiophenes they are of special interest in molecular electronic devices. In addition, both forms of 1b and 2b present absorption bands whose excitation gives very large differences in fluorescence between the two forms with very little effect on the opening/closing state, a feature of interest for optical memory data systems.