Interaction between porphyrins and hydroxylated compounds. Part 2. Effect of p-nitrophenol during the metallation of tetraphenylporphyrin

Abstract

The behaviour of tetraphenylporphyrin during its metallation with copper(II) acetylacetonate has been investigated in the presence of p-nitrophenol in benzene and in dichloromethane. Rate constants have been measured, and the forward reaction has been shown to be catalysed by p-nitrophenol. The kinetic orders of reaction were 1, 1, and 0.5 in porphyrin, p-nitrophenol, and Cu(acac)₂ respectively in both solvents. Moreover, in CH₂Cl₂ a dimeric form of Cu(acac)₂ was observed; only the monomeric species reacts with the porphyrin. A general mechanism is proposed.