Theoretical Study on Reactions of Triplet Excited State Thioxanthone with Indole

In the present work, a theoretical study on the deactivation of triplet excited (T(1)) state thioxanthone (TX) by indole (INH) was performed, based on density functional theory calculations. Three feasible pathways, namely direct electron transfer from INH to T(1) state TX, electron transfer followed by proton transfer from INH(.+) to TX(.−), and H-atom transfer from nitrogen of INH to keto oxygen of T(1) state TX, were proposed theoretically to be involved in T(1) state TX deactivation by INH.