Tunnelling effects in the oxidative addition of a dihydrogen molecule to the palladium ethylenediphosphine complexes [H2P(CH2)2PH2]Pd and [H2P(CH2)2PH2]Pd2

In terms of the reaction-path Hamiltonian formalism, the ligand environment has been found to have almost no effect on the activation barrier in the oxidative addition of H₂ to the title complexes (the under-barrier tunnelling in the reaction was predominant at T < 230 K).