Luminescence and Energy Transfer in Some Aliphatic α-Diketones

Strong phosphorescence is observed in all aliphatic α-diketones in rigid media at 77°K. In fluid solution at 25°C there is a decreasing phosphorescence intensity with the increasing length of one of the side chains. This effect is shown to be due to the increased probability of radiationless deactivation with increasing chain length. All the aliphatic α-diketones are good acceptors in triplet—triplet energy transfer and can be studied by diffusion-controlled sensitized phosphorescence techniques.