Cinétique de la formation de la métalloporphyrine Cu(II)—dérivé tétra éthylènediamino de la protoporphyrine IX (ENP) en milieu aqueux

The kinetics of formation of the metalloporphyrin Cu(II)–ENP is dependent on the pH due to the protonation of the pyrrol nitrogen atoms and the protonation of the diamino groups of the side chains. The degree of protonation of these side chains also influences the degree of association of the prophyrin and the metalloporphyrin in solution. The order of reaction with respect to the porphyrin is not unity, a consequence of an inhibition by the reaction product; this inhibition operates via the formation of a new species, a mixed complex of porphyrin–metalloporphyrin of low reactivity.The order of reaction with respect to Cu(II) is also not unity, a consequence of the chelation of Cu(II) by the diamino groups of the side chains. The presence of Cu(II) ligands influence both the reaction kinetics and the nature of the final reaction product. [Journal translation]