Effect of pH on formation of metalloporphyrins

Abstract

Although complexation reactions of porphyrins with metal salts in organic solvents have a long research history, the influence of pH on these processes was not studied. The main reason is complications connected with the pH measurements in nonaqueous solutions. To solve this problem the special instrumentation was created for application of the spectropotentiometric method (spectroscopy + pH-metry with glass electrode) in nonaqueous solutions. Using this method it became possible to investigate complexation reactions at different pH values using electronic absorption spectroscopy. The pH control of reaction systems allows us to explain the peculiarities of metalloporphyrins formation without invoking the Fleischer's idea of SAT-complexes. © ISUCT Publishing.