Other Systems that Exchange Hydrogens in H2 and Hydride Ligands

Other Systems that Exchange Hydrogens in H2 and Hydride Ligands 

An alternate structure for [ReH2(H2XCOXPR3)3]+ favored by Gusev and Berke2 contains H2 in the axial site trans to the strong acceptor CO, which would 

Although crystallographic evidence is unavailable, NMR data are compatible with averaging of the H positions in solution and cis interactions appear likely here. However, calculations indicate that the ground state structure is H(H2)2 rather than a pentahydrogen ligand analogous to Cp. 

Exchange of H atoms between -H2 and a bridging hydride is seen whenever the two groups are ds to each other [Eq. (6.9)]. Complexes include 

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