ABSTRACT
Photophysical behavior of the amphiphilic polyelectrolytes with a small amount of ZnTPP moieties as a hydrophobic chromophore was studied by absorption, fluorescence, phosphorescence, and transient spectroscopies. Absorption and emission spectra of amphiphilic polyelectrolyte in aqueous solution show that the zinc(II)-tetraphenylporphyrin(ZnTPP) moieties are compartmentalized in hydrophobic microdomain which is constructed by the aggregation of hydrophobic substituents. The triplet excited lifetime of the compartmentalized ZnTPP moieties at room temperature was found to be much longer than that of ZnTPP, and emitted phosphorescence and delayed fluorescence were observed even at room temperature.
The electron transfer reactions from ZnTPP moieties to Methylviologene (MV2+) and phenylmethyl-phenacylsulfonium p-toluenesulfonate(PMPS) were investigated by fluorescence spectroscopy and transient absorption spectroscopy. In the amphiphilic polyelectrolyte, MV+• and ZnTPP+• were clearly observed in the transient spectroscopy, although they could not be detected in polyelectrolyte with ZnTPP moieties. These results indicate that back electron transfer reaction is retarded remarkably owing to the compartmentalization of ZnTPP moieties.
