Photoreactivity of tetra-substituted anthracene derivatives and their mesophases

Novel tetra-substituted anthracene derivatives were synthesized, and their liquid crystallinities were characterized by using polarizing optical microscopy, DSC, and XRD. Although photodimerization of the anthracene derivatives proceed quantitatively upon irradiation with high-pressure mercury lamp in chloroform, the photoirradiation of the mesophases of these derivatives did not yield the corresponding photodimers. XRD analysis of the mesophases showed unusual stacking of anthracene moieties, which have insufficient orbital overlap. Structural analysis is consistent with the photoreactivity.