Axially Chiral peri-Xanthenoxanthenes as a Circularly Polarized Luminophore

A series of axially chiral peri-xanthenoxanthenes (PXXs) were synthesized from 1,1'-bi-2-naphthol without optical resolution. These are the first examples of chiral PXXs. Among them, PXX 5 with two naphthalene rings connected via a methylenedioxy bridge and a chiral axis displayed intense fluorescence (FL) and circularly polarized luminescence (CPL) both in solution (Phi(FL) of 0.72 and vertical bar g(Ium)vertical bar of 1.4 X 10(-3)) and in the solid state (Phi(FL) of 0.13 and vertical bar g(Ium)vertical bar of 4.8 X 10(-3)). The bridged structure of PXX 5 adjusts the angle between the vectors of the electric and magnetic transition dipole moments, which is essential for showing intense CPL activity.