Isotope Effects in C−H Bond Activation Reactions by Transition Metals

The activation of alkane C-H bonds by oxidative addition and its reverse reaction, reductive elimination, are believed to occur via transient sigma-alkane complexes. This Account summarizes how isotope effects can be used to probe the nature of these intermediates and points out some pitfalls in interpreting kinetic data. Comparisons are made with arene C-H activation and other activation systems.