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 (g(lum)). We demonstrate that a figure-eight-shaped molecule with D-2 symmetry has excellent chiroptical properties (Phi(f) = 0.08, vertical bar g(lum)vertical bar = 1.5 x 10(-2)), which are attributed to the parallel arrangement of mu and m as well as a good vertical bar mu vertical bar/vertical bar m vertical bar ratio.