PHOTOPHYSICS AND PHOTOCHEMISTRY OF TETRAANTHRAPORPHYRAZINES - ATTEMPTS TO OBTAIN A NEW-GENERATION OF PHOTOSENSITIZERS

Linearly benzo-annulated copper porphyrazines, such as octaphenyltetraanthraporphyrazinato-copper and octapentoxytetranaphthoporphyrazinato-copper, with absorption maxima at about 880 nm, were synthesized. These compounds exhibit very low-lying triplets with an energy below the activation energy of singlet oxygen. Therefore they do not generate singlet oxygen. The transient absorption spectra of the T(l)-T(x) transition were measured. The solvent dependence of the photophysical parameters in the triplet manifold is discussed. On irradiation in the presence of CBr4, pi-Cation radicals are formed.