Surface Enhanced Raman Scattering (SERS) of tetrasodium meso-tetrakis (4-sulfonatophenyl) porphine (H2TSPP) and silver tetraphenylporphyrin (Ag(Ⅱ)TSPP)adsorbed spontarleously on uniform Fe3O4 colloids are recorded. The enhancement of Raman bands is approximately 30. An analysis of the SERS spectrum shows that on the Fe3O4 surface H2TSPP takes its diacid form H42+TSPP.
The effect of cations(H +,Li +,Na + and K +) on the J aggregation of tetrakis( p sulfonatophenyl) porphyrin diacid (H 2+ 4TSPP 4- ) was studied by UV Vis absorption spectra.It was demonstrated that the presence of these cations promotes the J aggregation of H 2+ 4TSPP,implying that the external cations are necessary to balance the Coulomb repulsion between the sulfonate groups of adjacent H 2+ 4TSPP 4- molecules in the J aggregate.The excitionic energy of the J aggregate was evaluated under the dipole dipole interaction,which is qualitatively consistent with the experimental result.The results support the staircase structural model of the aggregate.
