Solvent Effect on the Stabilization of the Monoprotonated Species of Tetraphenylporphyrin

Solvent Effect on the Stabilization of the Monoprotonated Species of Tetraphenylporphyrin

Alvin Sherman Library

The protonation of Tetraphenylporphyrin (TPP) demonstrates unusual behavior where protonation causes only the formation of a diprotonated species. This behavior is due to a change in conformation leading to an unstable saddle deformation in which the monoprotonated species is highly unfavorable. The stabilization of the unfavored conformation in the monoprotonated intermediate species may be achieved by understanding the effects of different solvents on the protonation of TPP. This study was done to explore the protonation of TPP using Toluene Chloroform, and Dichloromethane using trifluoroacetic acid and chloroacetic acid to analyze the effects of the different solvents. Using a UV spectrophotometer, the analysis of the different wavelength absorptions can be used to calculate the solvents effect on the apparent pKa. This research can further our understanding of the effects of solvents on the stabilization of changes in conformation in TPP and allow stabilization of intermediates of other substituted porphyrins that exhibit similar behavior. Computational analyses were done to correlate experimental results.