Ground-State Electronic Structure in Charge-Transfer Complexes Based on Carbazole and Diarylamine Donors

The geometries, binding energies, and amounts of charge transferred in the ground state for a series of donor/acceptor organic pi-pi complexes have been characterized at the density functional theory level. We find that these compounds exhibit important changes in geometry upon complexation that is accompanied by a large binding energy. The amount of charge transferred from the donor to the acceptor depends highly on the substitution of the donor and can be roughly described by the electron donating or withdrawing ability of the substituent. Interestingly, there is a significant difference in the behavior of carbazoles and diarylamines upon substitution.