Modeling of efficient charge transfer materials of 4,6-di(thiophen-2-yl)pyrimidine derivatives: Quantum chemical investigations

Abstract

The 4,6-di(thiophen-2-yl)pyrimidine has alternate pi-rich and pi-poor units. To reduce the HOMO–LUMO energy gap and improve the intra-molecular charge transfer pi-backbone has been elongated along with push–pull strategy. The ground state geometries have been optimized by using density functional theory. The frontier molecular orbitals, i.e., highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) have been conferred. The absorption spectra have been computed by using time dependent density functional theory. On the basis of ionization potentials, electron affinities and reorganization energies charge transfer properties have been discussed. We tuned the electronic, photophysical and charge transfer properties of 4,6-di(thiophen-2-yl)pyrimidine derivatives. It is expected that new designed derivatives might be better/comparable to commonly used hole transfer material (pentacene). The smaller reorganization energies revealing that the electron transfer properties of new designed derivatives might be better/comparable to commonly used electron transfer materials (tris(8-hydroxyquinolinato)aluminum). The structure–property relationship has been discussed.