Polyaromatic phosphetenes: versatile platforms for circularly polarized luminescence generation through chiral perturba-tion

We describe the synthesis of four new polyaromatic fluoro-phores fused to a phosphetene ring (4-membered P-ring). These compounds are fully characterized including X-ray diffraction. Due to the presence of the stereogenic P-atom, all compounds are found as racemic mixture, which could be separated by chiral separation. The impact of both the poly-aromatic platform and the P-ring on the structure, 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 HOMO or LUMO orbitals, both of these structural features have an important modulating role in distorting the symmetry of the orbitals, leading to chiroptical properties. In this case, the stereogenic P-atom is used as chiral perturbator to induce circularly po-larized luminescence of the polyaromatic system