The mechanism of peracetic acid interaction with Mn(III) complexes of tetra-R-tetra-tert-butyl-tetraazaporphines (RTAPM-nCl, R = H, Br, PhSO2, NO2) in acetonotrile/acetic acid solutions has been studied. Analysis of the kinetic data of trans-stilbene epoxidation, naphthalene hydroxylation, 1, 1 -diphenyl-2-picrylhydrazine (DPPH), and tetra-4-tert-butyl-phthalocyanine zinc (PcZn) one-electron oxidations revealed the reversible formation of a two-center molecular "catalyst-oxidant" complex ligated with a molecule of acetic acid { A = [RTAPMn(AcOOH)(AcOH)] (X)}. The subsequent irreversible transformation of A with rate constant k(2) leads to the formation of two high-valent oxometallo species, supposedly [RTAPMn(V)(O)(AcOH)](X) and [(.+)RTAPMn(IV)(O)(AcOH)](X), which are in equilibrium and show distinct oxidation abilities towards olefin and naphthalene. The Hammett-type dependencies of k2 and of the rate constant of A formation (kj) have been analyzed and compared with those ones determined earlier for Mn(III) meso-tetra(2,6-dichloro-4-R-phenyl)porphyrins (RTDCPPM-nCl). The enhanced sensibility of the acceptor properties of Mn ion to electronegative substitution in tetraazaporphine macrocycle is considered to be a reason of the highest catalytic oxidative activity of Mn-tetra-nitro-tetra-tert-butyltetraazaporphine within studied Mn porphinoids.