The reaction of Mn(II) with tetrakis(N-carbomethoxymethyl-3-pyridyl)porphyrin bromide catalyzed by Hg(NO3)2 was studied in borax buffer. The incorporation of Mn(II) into the porphyrin occurred by sitting atop the intermediate compound The effects of concns. of catalyst and metal ion and pH of solution are discussed. The observed rate constant of the reaction is kebs - [Hg2+=[Mn2+]/(k[H+] + k[Mn2+]) where k0 = 26.20 mol.dm-3.s and k = 2.59 ?10-5 mol.dm-3.s. The mechanism of the reaction is proposed. The deformation of the porphyrin ring is the general condition for metal incorporation into porphyrin.

Key words: PYRIDINE P, CATALYSIS, REACTION MECHANISM, REACTION KINETICS, MANGANESE, NITRATE, REACTION RATE CONSTANT, MERCURY COMPOUNDS, BORAX, INTERCALATION REACTION