THE PHOTOPHYSICAL PROPERTIES OF PORPHYCENES: POTENTIAL PHOTODYNAMIC THERAPY AGENTS

Porphycene and a tetra‐n‐propyl derivative remained unaltered on irradiation in toluene at room temperature. Quantum yields of fluorescence, S T intersystem crossing, and singlet molecular oxygen sensitization, as well as lifetimes of the singlet and triplet excited states were measured. In view of their structural relationship to porphyrin, their high absorption above 620 nm, their stability towards photooxidation, and their high quantum yields of fluorescence and singlet oxygen sensitization, these compounds qualify as potential agents for tumor marking and photodynamic therapy.