pH-controlled location and metalation of an amphiphilic porphyrin in sodium dodecyl sulfate micelle

5,10,15-Tri(4-hydroxyphenyl)-20-(4-hexadecyloxyphenyl)porphyrin (P) was solubilized in sodium dodecyl sulfate (SDS) micelle solutions. Taking advantage of the protonation and deprotonation properties of the amphiphilic porphyrin allowed the study of the pH-controlled transfer process of P in SDS micelle by means of UV–vis and fluorescence spectra. In neutral SDS micelle, P may be protonated and located at the outer surface of the micelle. In mildly basic conditions the hydrophilic ability of P decreases and the porphyrin moiety may transfer to the inner layer of SDS micelle. In strong basic conditions the porphyrin may transfer back to the outer aqueous surface of the micelle. The kinetic study of the porphyrin complexed with Cu(II) shows that the metalation rate of P could be controlled by changing the pH.Key words: porphyrin, location, metalation, sodium dodecyl sulfate, micelle.