The Effect on Porphyrin Basicity of Fluorine Substituted Meso Phenyl Porphyrins
Abstract
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.
Faculty Sponsors
Dr. Maria Ballester, Dr. Victor Castro, Dr. Brian Van Hoozen
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-5-2023 12:00 PM
End Date
4-6-2023 4:00 PM
The Effect on Porphyrin Basicity of Fluorine Substituted Meso Phenyl Porphyrins
Alvin Sherman Library
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.
