Effect of protonation on the spectral properties of subphthalocyanine and tripyrazinosubporphyrazine

Abstract

Abstract Using well-known methodology perfluorinated sybphthalocyanine (F12 sPcBCl) and hexaphenyltripyrazinosubporphyrazine (Ph6Pyz3sPzBCl) were obtained and further its spectral and base properties have been studied by spectrophotometric titration and fluorescence spectroscopy. By means of spectrophotometric titration sequential protonation of two azomethine bridges was observed with the shifts of the absorption Q bands to 625-665 nm (for F12 sPcBCl), to 584-683 nm and CT (charge transfer) band to 426-453 nm (for Ph6Pyz3sPzBCl). The spectral changes in the electronic absorption spectra of F12sPcBCl observed in an acid medium differ significantly compared to Ph6Pyz3sPzBCl. Protonation of Ph6Pyz3sPzBCl was observed in 0.08-0.35 M solution of trifluoroacetic acid in dichloromethane, in contrast to F12 sPcBCl for which protonation in dichloromethane was observed at TFA concentration equal to 1.34 M. Bathochromic shift of the Q bands in the emission spectra was indicated for each of the protonated forms of the compounds, accompanied by a decrease in the fluorescence intensity with increasing acidity.