Coordinated acylimido complexes formed by reaction of nitridorhenium and nitridomolybdenum porphyrins with substituted acetic anhydrides†
Abbreviations used: X−, monovalent anion; POR, porphyrin dianion; TPP, tetraphenylporphinato dianion; TTP, tetrakis(4-methylphenyl)porphinato dianion; OEP, octaethylporphirato dianion; AA, acetic anhydride; MCAA, monochloracetic anhydride; DCAA, dichloroacetic anhydride; TCAA, trichloroacetic anhydride; TFAA, trifluoroacetic anhydride.
Abstract
Acylimidorhenium and molybdenum porphyrin complexes were prepared by reaction of the corresponding nitridometalloporphyrins with substituted acetic anhydrides and their spectral and electrochemical properties were determined. Analysis of the electronic spectral changes with time and initial reactant concentration confirmed that the acylimido formation reaction was first-order in each reactant and second-order overall. Second-order rate constants for formation of the chloroacetic anhydride complex increased in the order Mn<Cr<Re<Mo. In contrast with the previously reported reactivity of acylimidomanganese and chromium porphyrin complexes, the rhenium and molybdenum derivatives were unreactive towards triphenylphosphine, strained olefins and silyl ethylene ethers. © 1998 John Wiley & Sons, Ltd.
