PHOTOINDUCED REACTIONS OF COVALENTLY-LINKED PORPHYRIN QUINONES IN REVERSED MICELLES AS STUDIED BY EPR SPECTROSCOPY

From covalently linked porphyrin quinones, dissolved in reversed micel lar solutions, porphyrin radical cations and semiquinone radical anion s can be generated photochemically. At pH 7 of the water pool the radi cal species are rather short-lived and can thus only be observed durin g in-situ light irradiation (optical pumping) of the sample. Different polarization patterns are observed in different types of micelles, e. g., CTAB cationic or Triton X-100 neutral reversed micelles. Specifica lly, in the former absorptive (either Boltzmann relaxed or enhanced ab sorptive) spectra are obtained, whereas in the latter both species (po rphyrin radical cation and semiquinone radical anion) occur in emissio n. Complete emission is indicative of a strong triplet mechanism.