Chemistry and Physics Faculty Proceedings, Presentations, Speeches, Lectures

Event Name/Location

American Chemical Society Spring 2022 Conference

Event Name

Spring 2022 Conference

Event Location

San Diego, California

Document Type


Publication Date

Spring 3-23-2022


The protonation of meso-Tetra(2,3,4-trifluoromethylphenyl) porphyrin (TF) and meso-Tetra(pentafluorophenyl) porphyrin (PF) will be studied through UV vis spectroscopy. Protonation is achieved by titration of each porphyrin in toluene with trifluoroacetic acid (TFA). The presence 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 TF upon protonation was 2.07, while the average pKa for PF was 1.36 over four trials. A greater acidic value for PF was indicated from these results. In addition, a significant increase in the amount of acid added was noted during the protonation of PF when compared to the amount of acid needed for TF. This could indicate a correlation between the fluorinated position in the porphyrin and the formation of dication.