Porphyrin Tautomerization for the 5,15-dibromo-10,20-diphenylporphine and 5 bromo-10,15,20- triphenylporphine using VT H1NMR

Variable-temperature proton NMR spectroscopy, as well as theoretical studies, will be used to compare the reported free energy of activation value of the tetra phenyl porphyrin (12.2 kcal/mol), the 5, 15 phenyls substituted porphyrin with an in-plane distortion (11.6 kcal/mol) with the 5,15-dibromo-10,20- diphenylporphine and 5 bromo-10,15,20-triphenylporphine. The experimental determination of tautomerization using VT H1NMR of both porphyrins is to be compared to the molecular modeling analysis of the porphyrin structure using MM+