Quasi-isoenergetic triplet energy migration in homogeneous solution

Intermolecular triplet energy migration in alkyl aryl ketones is shown to be a very fast process. In quasi-isoenergetic examples the rate constants are in the neighborhood of 10¹⁰ M^? s^? in n-heptane at room temperature. The process is rather insensitive to alkyl α-substitution in the donor triplet state and is substantially faster than the analogous transfer in aliphatic ketones.