Phosphetene‐Based Polyaromatics: Structure‐Property Relationships and Chiroptical Tuning

We describe the synthesis of π‐extended phosphetene rings (4‐member P‐rings) flanked with PAH systems of various topologies. These compounds are fully characterized including X‐ray diffraction. The impact of both the polyaromatic platform and the P‐ring on the structure, and the optical and redox properties are investigated both experimentally and theoretically. Although neither the P centre nor the 4‐membered ring significantly takes part in the HOMO or LUMO orbitals, both structural features have an important modulating role in distorting the symmetry of the orbitals, leading to chiroptical properties. The stereogenic P‐atom is used as a remote chiral perturbator to induce circularly polarized luminescence of the polyaromatic system. The dissymmetry factor is highly dependent on the polyaromatic topology, as supported by theoretical calculations. The synthesis of phosphetene rings (4‐membered P‐ring) flanked with PAH systems is described. Although neither the P centre nor the four‐membered ring participate in the frontier orbitals, both structural features play an important role in modulating the symmetry of the orbitals, resulting in chiroptical properties. The stereogenic P‐atom was used as a chiral perturbator to induce circularly polarized luminescence of the polyaromatic system.