Photoinduced Intramolecular Proton Transfer and Intermolecular Hydrogen-Atom Abstraction of I-Piperidinoantraquinone (PAQ)

The lowest excited singleL and triplet states of PAQ give rise to furmaLion of the N-ylide compound at 77 K and the reduced compound at room temperature, respectively. In the latter case, however, indirect population of the lowest excited triplet state from a higher excited singlet state (through a higher excited triplet state) is very important.