Effect of Weak Interactions on the H···H Distance in Stretched Dihydrogen Complexes

Computational and experimental results presented in this paper demonstrate that the H−H
distance in stretched dihydrogen complexes can be hypersensitive to a variety of weak intra- and
intermolecular interactions, including those with bulky ligands and solvent molecules, hydrogen-bonding
interactions, or ion-pairing. Particularly, the complex IrH(H···H)Cl2(PiPr3)2 which contains a stretched
dihydrogen ligand in the crystalline form, as shown by neutron diffraction, is a trihydride in solution. The
difference is due to the intermolecular Ir−Cl···H−Ir hydrogen bonding in the solid.