A pH-controlled process - Transfer of amphiphilic porphyrins from the inner core to the outer surface of CTAB micelles

A series of amphiphilic porphyrins, 1, 5,10,15-tri(4-hydroxyphenyl)-20-(4-hexadecyloxyphenyl)porphyrin, 2, 5,15-di(4-hydroxyphenyl)-10,20-di(4-hexadecyloxyphenyl)porphyrin, and 3, 5-(4-hydroxyphenyl)-10,15,20-tri(4-hexadecyloxyphenyl)porphyrin were solublized in cetyltrimethylammonium bromide (CTAB) micellar solutions. By taking advantage of the deprotonation property of the hydroxylphenyl groups and the pyrrole groups of the amphiphilic porphyrins and the UV-vis spectral sensitivity of their Soret bands to the microenvironment of the porphyrin moiety, a pH-controlled transmembrane process was studied in detail by means of UV-vis spectroscopy. The influence of the number of hexadecyl groups and the concentration of added salts on the transfer process was analyzed.