9,10-Diaminoanthracenes Revisited: The Influence of N-Substituents on Their Electronic States.

The electronic and molecular structures of 9,10-diamino-substituted anthracenes with different N-substituents have been re-examined. In particular, different N-substituents influence both the electronic and molecular structures of the oxidized species of 9,10-diaminoanthracenes. The anthrylene moiety of 9,10-bis(N,N-di(p-anisyl)amino)anthracene retains its planarity during the course of two successive one-electron oxidations, whereas 9,10-bis(N,N-dimethylamino)anthracene and 9,10-bis(N-p-anisyl-N-methylamino)anthracene undergo a substantial structural change to a butterfly-like structure through a two-electron oxidation process. The structural changes observed for the oxidized states are ascribed to significant differences in the frontier molecular orbitals of the above-mentioned three kinds of 9,10-diaminoanthracenes due to different extents of mixing between the amine-localized and anthrylene-localized orbitals.