Abstract:

The effects of  acids (HCl,H₂SO₄,HBr and HNO₃) on meso\|tetraphenylporphyrin (H₂TPP) in dichloromethanesolution were investigated by means of   UV/Vis absorption combined with Raman scattering techniques, the electronic absorption spectrum shows the J\|aggregate of H2TPP is formed in the presence of HCl, HBr or HNO3, but both of H\| and J\|aggregates are formed in the presence of H₂SO₄ characteristic double bands at 818/834 cm^-1and 1 072/1 093 cm^-1 represented the main vibrational frequency difference between H\| and J\|aggregates.  Raman spectra of aggregate H₂TPP in the presence H₂SO₄ in dichloromethane, toluene and chloroform solutions show the dependence of aggregation behavior on the nature of solvent. The conclusion is that H₂TPP diacid has a tendency to form J\|aggregate in high solubility solvents, but both H\| and J\|types of aggregates in the relative low solubility ones.

Key words: meso-, tetraphenylporphyrin, Raman spectrum, aggregate, electronic absorption spectrum