Relaxation Process of the Photoexcited State and Singlet Oxygen Generating Activity of Water-soluble meso-Phenanthrylporphyrin in a DNA Microenvironment

摘要: To examine the microenvironmental effect of DNA on photosensitized reaction, electron-donor-connecting porphyrin, meso-(9-phenanthryl)-tris(N-methyl-p- pyridinio)porphyrin (Phen-TMPyP), was synthesized. Phen-TMPyP can bind to oligonucleotides with two binding modes, depending concentration. The fluorescence lifetime measurement shows a shorter component than that reference porphyrin without phenanthryl moiety. However, observed value is much longer those previously reported similar types porphyrins, suggesting electron- transfer quenching by moiety not sufficient. quantum yield (5 μM) decreased an increase in concentration up 5 μM base pair (bp), possibly due self-quenching through aggregation along strand, increased more bp and reached plateau. sufficient larger porphyrin. singlet oxygen ( 1 O2) generating activity confirmed near- infrared emission spectrum measurement. O2 generation relatively small DNA, Phen-TMPyP, recovered DNA. rather smaller indicating O 2 These results show strand stabilize photoexcited state photosensitizer and, certain case, suppresses generation.