Orthogonally Arranged π-Electronic Systems with Anion-Responsive Moiety Exhibiting Photoinduced Electron Transfer

Orthogonally arranged π-electronic systems comprising directly connected electron-deficient and anion-responsive moieties were synthesized by the connection of acridine/<i>N</i>-methylacridinium and dipyrrolylpyrimidine (dpp) units. Acridine- and <i>N</i>-methylacridinium-substituted dpps showed anion-binding behaviors via hydrogen bonding at pyrrole NH and pyrimidine CH, suggesting the possibility of modulating the electronic states of the anion-responsive π-electronic systems. Transient absorption measurements of the acridine-substituted dpp revealed a photoinduced electron transfer from the anion-responsive unit to the electron-deficient moiety, which was accelerated by anion binding.