The protonation of meso-tetra(2,6-difluoromethylphenyl) porphyrin (2,6-DF), meso-(3,5-difluoromethylphenyl) porphyrin (3,5-DF), and meso-tetra(2,3,5,6-tetrafluorophenyl) porphyrin (TF) will be studied through UV-Vis spectroscopy. Protonation is achieved by titration of each porphyrin in toluene with trifluoroacetic acid (TFA). The depiction of a wavelength shift from the free base Soret to the protonated Soret will indicate the formation of a dication. The data from the UV spectra will be used to calculate the pKa values associated with each porphyrin. Based on the results, the average pKa for 2,6-DF upon protonation was 1.67, the average pKa for 3,5-DF was 1.75, and the average pKa for TF was 1.31. A greater acidic value for TF was indicated from these results. In addition, a similar acidic value was demonstrated for both 2,6-DF and 3,5-DF; however, the 2,6-DF showed greater acidic character. This could indicate a correlation between the fluorinated position in the porphyrin as well as the number of fluorine substituents in relation to the formation of dication.

Effect on porphyrin basicity of fluorine substituted meso phenyl porphyrins

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.