Photoinduced reactions. Part 147. Photochemistry of 1-isopropylanthrone

Abstract

The triplet state of 1-isopropylanthrone (8) was found to be very short-lived (45 ± 25 ps) in view of its effect on the triplet-sensitized isomerization of cis-piperylene. This result agrees with our previous conclusion that the triplet lifetime of 2,4,6-tri-isopropylbenzophenone (1) is controlled by hindered rotation in the excited state. Measurement of absorption and emission spectra for (8) has revealed that the keto–enol equilibrium for (8) is overwhelmingly on the side of the keto-form even in ethanol.