Meso-substitution reactions of rhodium(III)–octaethylporphyrins with organolithium reagents

Abstract

Nucleophilic attack of organolithium reagents towards the trivalent rhodium–octaethylporphyrin (1) occurs initially at the rhodium atom. Subsequent nucleophilic attack occurs at the meso-position of the porphinate core. Monitoring the reaction by u.v–visible spectroscopy shows that the axial co-ordination sites are occupied by carbanions to give the hyper-type porphyrin complex (2) at the first stage, and then the phlorin-type complex (3) is formed. Alkyl- and aryl-rhodium(III) complexes (4)–(6) of mono-meso-alkyl- and -aryl-octaethylporphyrins have been obtained by the oxidation of the phlorin-type complexes.