Peripheral Stepwise Degradation Of A Porphyrin J-Aggregate
For metalation of the acidic form of tetrakis(4-sulfonatophenyl)porphyrin (dianionic H₄TPPS₄) by Cu(II), the order of reagent mixing determines the rate and mechanism of CuTPPS₄ formation. When copper salts are added last, the kinetic profile is fit as a (pseudo)-first-order process. However, J-aggregates of the H₄TPPS₄ porphyrin are rapidly formed at pH similar to 3 when Cu(II) salts are incorporated in solution prior to porphyrin addition. The subsequent porphyrin units metalation leads to the disassembling of these arrays via a pseudo-zero-order kinetic profile, suggesting an attack of the metal ion at the rims of the nanostructure.
I. Occhiuto, G. de Luca, M. Trapani, L. M. Scolaro, and Robert F. Pasternack.
"Peripheral Stepwise Degradation Of A Porphyrin J-Aggregate".