1H NMR SPECTROSCOPIC STUDY OF HYDROGEN BONDS AND MOBILE NH PROTONS IN AQUEOUS SOLUTIONS OF PORPHYRIN IONS

The concentration and temperature dependence of the chemical shifts of aromatic and β-protons of tetra-meso substituted porphyrin ions in aqueous solution have been investigated. A considerable increase in the localization temperatures of interior NH protons of porphyrins dissolved in water compared to solutions of porphyrins in organic solvents was observed. Types of association of the porphyrins studied and the possibility of intra- and intermolecular hydrogen bonds are discussed.