Extraordinary Dynamics of Dihydrogen Complexes

H2 ligands can occur, even in the solid state at temperatures below 77 K, with activation barriers as low as 1.5 kcal mohi  

For the H2 ligand, the structure and dynamics are much more extensive and richer than for hydride ligands. These can include rotational/vibrational motion of binding and splitting of H2 (including equilibria between 72.H2/dihy- 

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