Solid-State Photodimerization of Anthracenes Having a Chiral Substituent

Abstract

Abstract Anthracenes containing a chiral substituent at the 9-position, AnCH(OAc)R (An = 9-anthryl; R = Me, Et, i-Pr, t-Bu, CF3), dimerized on UV irradiation in benzene to give two head-to-tail dimers, meso- and dl- forms with 1:1 ratio. In the solid state, some (R˭Et, i-Pr) gave one dimer exclusively, while in another case (R˭Me) dimerization proceeded slowly to give both dimers. The solid-state photochemical behavior can be explained based on the crystal structure.