Circularly Polarized Luminescence Designed from Molecular Orbitals: A Figure-Eight-Shaped [5]Helicene Dimer with D2 Symmetry.

Although many chiral molecules exhibiting circularly polarized luminescence (CPL) have been reported recently, few molecular design guidelines are known for increasing the dissymmetry factor for CPL (glum). We demonstrate that a figure-eight-shaped molecule with D2 symmetry has excellent chiroptical properties (Φf = 0.08, |glum| = 1.5 × 10-2), which are attributed to the parallel arrangement of μ and m as well as a good |μ|/|m| ratio.