In this work, tetraiodide and tetratosylate of 5,10,15,20-tetrakis(N-methyl-3′- pyridyl)chlorin, as well as tetraiodide 5,10,15,20-tetrakis(N-methyl-3′-pyridyl)porphyrin, the effect of the nature of counterions and the macroring on the ability of photosensitizers to generate singlet oxygen and superoxide radical anion under oxygen-enriched and depleted condition were studied. Under oxygen-depleted condition, the efficiency of photosensitizers decreases; therefore, we evaluated the possibility of triggering the photodynamic action of photosensors by a radical mechanism (type I) and its potentiation with potassium iodide in these conditions. Potentiation of BSA photooxidation processes with potassium iodide showed that the use of chlorins as sensitizers is more effective than porphyrins.
