5-(2-quinolyl)tetrabenzoporphyrin and Its complexes with zinc, cobalt, copper and manganese. Synthesis, spectral, electrochemical and electrocatalytic properties

By reacting phthalimide with quinaldine in the presence of zinc oxide, 3-(quinolin-2-ylmethylene)isoindolin-1-one was synthesized. Heating its mixture with excess phthalimide and zinc acetate leads to the formation of zinc 5-(2-quinolyl)tetrabenzoporphyrinate, which, when treated with acid, is converted to 5-(2-quinolyl)tetrabenzoporphyrin. The latter, when interacting with cobalt(II), copper(II) and manganese(II) chlorides in DMF, forms the corresponding metal complexes. The composition and structure of the obtained compounds were confirmed by a complex of physicochemical methods of analysis. The results of quantum-chemical calculations of complexes by DFT and TD-DFT methods are presented. The first absorption bands in theoretical electronic spectra are assigned to the corresponding electronic transitions in molecules. All synthesized tetrabenzoporphyrins have catalytic activity in the electroreduction reaction of oxygen; the cobalt complex exhibits the greatest activity.