Hydrogen tunneling with an atypically small KIE measured in the mediated decomposition of the Co(CHCOOH) complex.

Quantum mechanical tunneling (QMT) is a well-documented phenomenon in the C-H bond activation mechanism and is commonly identified by large KIE values. Herein we present surprising findings in the kinetic study of hydrogen tunneling in the Co mediated decomposition of acetic acid and its perdeuterated isotopologue, conducted with the energy resolved single photon initiated dissociative rearrangement reaction (SPIDRR) technique. Following laser activation, the reaction proceeds along parallel product channels Co(CHO) + CO and Co(CHO) + HO.