Unusual Fluorescent Properties of 3,4,6-Triphenyl-α-pyrones

Novel fluorophores, 3,4,6-triphenyl-α-pyrone derivatives, were synthesized and their spectroscopic properties have been investigated. In the solid state they show intense greenish-yellow fluorescence, but not in solution. It is concluded that the 6-phenyl group is fixed at an angle of about 26° to the pyrone plane in the solid state by molecular packing and this fixation is required for this unique fluorescent property.