Tuning the HOMO–LUMO Gap of Pyrene Effectively via Donor–Acceptor Substitution: Positions 4,5 Versus 9,10

Donor and acceptor substituents were introduced at pyrene’s K-regions in order to engineer its optoelectronic properties. A study of the influence of the substitution pattern on the frontier orbitals as well as on the molecular packing is provided. A comparison with the pure donor and acceptor substituted pyrene derivatives highlights the strong impact of the presented donor–acceptor substitution.