Competing Coordination and Oxygen Atom Transfer in a Reaction Between Triarylphosphines and a Chromium Hydroperoxo Complex

There is a remarkable resemblance in the chemistry and intermediates involved in the autoxidation of a macrocyclic Cr(II) complex LCr(H2O)2 (L1 = 1,4,8,11-tetraazacyclotetradecane, or cyclam) and the activation of molecular oxygen by cytochrome P450 enzymes [1,2]. For every major step in the P450 chemistry there is a corresponding step in the chemistry of L1Cr complex, including the hydroperoxo to high-valent oxo conversion of eq 1. The kinetics of this transformation have been studied earlier [2,3].