The review presents data on the complexation of octa(m-trifluoromethylphenyl)porphy-razine and hexa(m-trifluoromethylphenyl)benzoporphyrazine with zinc acetate in a system nitrogen-containing base - benzene. It was shown that the investigated porphyrazines, having pronounced acidic properties at the incyclic NH bonds, interact with n-butylamine, tret-butylamine, morpholine and piperidine in benzene with the formation of proton-transfer complexes. In these complexes, the intocyclic protons of the NH-groups associated with the oxygen atom of the dimethyl sulfoxide molecule and the intocyclic nitrogen atoms are located above and below the plane of the macrocycle. In an inert, low-polar benzene, the degree of proton transfer from acid to base is limited by the stage of the H-complex (H-associate) formation or ionic complex (ion-ion) associate. It was found that proton transfer complexes of octa(m-trifluoromethylphenyl)porphyrazine and hexa(m-trifluoromethylphenyl)benzoporphyrazine exhibit low kinetic stability. The role of this acid - base interaction in the complexation reaction of octa(m-trifluoromethylphenyl)-porphyrazine and hexa(m-trifluoromethylphenyl)benzoporphyrazine with zinc acetate is shown. High kinetic stability of zinc complexes with the investigated porphyrazines in contrast to complexes with proton transfer was revealed. Based on the analysis of kinetic data, it was found that the introduction of Zn2+ into the coordination center of octa(m-trifluoromethylphenyl)porphyrazine and hexa(m-trifluoromethylphenyl)benzoporphyrazine is preceded by the stage of interaction of porphyrazine with a nitrogen-containing base. This leads to the formation of an intermediate reactive acid-base complex that differs in composition from complexes with proton transfer of porphyrazines. It was shown that piperidine and n-butylamine exert the maximum catalytic effect on the formation of zinc complexes with the investigated porphyrazines. A decrease in the pKa of the nitrogen-containing base, as well as an increase in the spatial shielding of the nitrogen atom in the amine by alkyl substituents, counteracts the formation of an intermediate acid-base complex and, as a result, reduces the complexation rate of octa(m-trifluoromethylphenyl)porphyrazine and hexa(m-trifluoromethylphenyl)benzoporphyrazine with zinc acetate in benzene.
Specific features of the acid-base interaction of tetra(4-tert -butyl)phthalocyanine with cyclic and acyclic nitrogen-containing bases in dimethyl sulfoxide are studied. The effect of p K a of proton-withdrawing molecules, basicity of a medium, and steric screening of acidic NH centers on the kinetic parameters of formation of proton-transfer complexes stable in time is shown.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.