Energy profile of rapid, reversible oxidative addition reaction

The trimethyltin undergo a very fast, reversible oxidative addition reaction with [PtMe2(Bu2bipy)], Bu2bipy = 4,4′-di-tert-butyl-2,2′-bipyridine, to give [PtXMe2(SnMe3)(Bu2bipy)] for which a complete energy profile can be obtained by using variable-temperature NMR methods; the reaction with X = I is the fastest known oxidative addition and activation energies when X = Cl suggest detailed structure for the transition state.