Phosphorescence of singlet oxygen and 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphine: Time and spectral-resolved study

Comparison of photosensitization of singlet oxygen by anionic (TPPS4) and cationic (TMPyP) water-soluble photosensitizers based on direct time- and spectral-resolved luminescence of both the photosensitizer and singlet oxygen is presented. Concentration dependences of photosensitizer and singlet oxygen emission kinetics were investigated in buffer solutions of wide range of TMPyP and dissolved oxygen concentrations. The trends in TMPyP triplet kinetics were explained in the frame of transient charge-transfer complexes. The results provide new insight into interpretation of our previously published concentration dependences of TPPS4 triplet states kinetics.