Triplet-state reactions of hypericin: time-resolved laser photolysis and electron paramagnetic resonance spectroscopy

Hypericin (Hyp), a naphthodiantrone derivative carrying hydroxyl and methyl substituents, lately attracted much attention because of its possible use a therapeutic agent-especially against retroviral-induced diseases. Here, the excitcd triplet state of the molecule, 3 Hyp, is being studied by laser photolysis and by EPR spectroscopy both in ethanol and in a nematic liquid crystal