The complexation of 2-aza-21-carba-tetraphenylporphyrin and 2-aza-2-methyl-5,10,15,20-tetraphenyl21-carbaporphyrin with nickel and zinc acetates in organic solvents has been investigated by UV-Vis spectroscopy and H-1 NMR. It has been shown that the enhanced reactivity of these tetrapyrrolic macrocycles is mainly determined by their ability to exist in different tautomeric forms
