EXCITED-STATE PROPERTIES OF 2-ACRYLATED ANTHRAQUINONES

The absorption, fluorescence and phosphorescence properties of 2-acryl amido and 2-acryloxyanthraquinones are examined in different solvents. The latter has an unusual marked blue-shifted absorption maximum comp ared with that of the acrylamido derivative. Also, unlike most 2-subst ituted anthraquinones these molecules exhibit negligible fluorescence. In the former case, weak phosphorescence in observed which is associa ted with rapid deactivation of the lowest excited 1pipi state by inte rsystem crossing to the second excited 3npi state followed by interna l conversion to the lowest excited 3pipi state and hence radiative em ission to the ground-state. In the latter case, very strong phosphores cence is observed which appears to occur from the second excited 3npi state and resembles that of anthraquinone. No evidence is found for a low lying excited 3pipi state. This effect is associated with vibron ic coupling of the excited 1npi and 1pipi* states resulting in rapid intersystem crossing to the 3npi state followed by emission to the gr ound-state. The data are discussed in the context of their activities for photocrosslinking polymers.