Direct Kinetic Studies of Atom Transfer and Electron Transfer Reactions of Hydroperoxo and High-Valent Oxo Complexes of Chromium

A macrocyclic hydroperoxo chromium complex reacts with triphenyl phosphine in an acid-catalyzed oxygen-atom transfer reaction, k = 850 M^-2 s^-1. In a competing process, the hydroperoxo complex is converted to a dioxo chromium(V) species, which reacts with PPh₃ by electron transfer, k = 4.4 × 10⁵ M^-1 s^-1.