Effect of Internal BN Substitution on Electronic Properties of Pyrene Derivatives

Abstract

Abstract Pyrene as an important chemical building block has found wide applications in the field of organic electronics. In solution, pyrene and its derivatives are well-known examples for excimer formation. Here, we studied the boron-nitrogen (BN)-substituted pyrene, decorated with thiophene side chain. From density-functional theory (DFT) calculation, this isoelectronic BN substitution maintains the coplanarity of the central motif and the delocalized π-electron distribution, but additionally induces a much stronger permanent dipole moment. Time-dependent DFT indicates a much-reduced oscillator strength for low energy transitions, and surprisingly a forbidden π-π* transition, therefore resulting in a much red-shifted absorption spectrum. Our simulation results call for future experiments to study the photo-excited properties of BN-substituted pyrene and molecular self-assembly through dipole-dipole interaction and π-π* interaction.