Spectrophotometric Study of Acid-Base Properties of Sulfonated Derivatives of 5,10,15,20-Tetraphenyl-21-thiaand 5,10,15,20-Tetraphenyl-21-oxoporphyrins in the Ethanol–Sulfuric Acid System

Abstract

Spectral and basic properties of heterosubstituted porphyrins of anionic type have studied by means of spectrophotometric titration in comparison with their structural analog — tetraphenylporphine tetrasulfonic acid. The parameters of electronic absorption spectra and concentration ranges of existence of the mono- and diprotonated forms of the studied ligands as well as the constants of basic dissociation have been determined. Comparative analysis of the effect of the reactive site modification and the medium composition on the basicity of the compounds has been performed.