These data correspond to a Gibbs acQvaQon energy of DG ‡ 373K = 29.6 kcal mol -1 . This value is inconsistent with either oxidaQve addiQon, migratory inserQon, or reducQve eliminaQon steps at a mono-phosphine palladium complex being turnover limiQng as each of these individual steps occur with lower barriers based on DFT calculaQons. Rather the experimental acQvaQon parameters most closely align with the barrier of the H2 splifng step from the DFT model (DG ‡ 373K = 23.4 kcal mol -1 ).