Phthalocyanine vs porphyrin: Experimental and theoretical comparison of the catalytic activity of N-bridged diiron tetrapyrrolic complexes for alcohols oxidation

Abstract

mu -Nitrido diiron porphyrinoids complexes, based either on porphyrins or phthalocyanines, are known as excellent oxidation catalysts. While many works have investigated the effect of the substitution pattern on their catalytic activity, a comparison of the effect of the macrocycle remains yet to be conducted. For this purpose, tert -butyl substituted (FePc) 2 N and (FePor) 2 N have been selected as they have both been thoroughly but separately used for oxidation catalysis. Herein, their catalytic activities were tested on model oxidation reactions of various alcohols. The phthalocyanine-based complex (FePc) 2 N proved to be a far more efficient catalyst than its porphyrin counterpart (FePor) 2 N . Computational studies rationalized these experimental observations by showing that the intermediates formed by ( FePc) 2 N are thermodynamically more stable than those formed by (FePor) 2 N .