Neutron Diffraction Studies of Metal-hydrides: Investigations of Oxidative Addition of Dihyrdogen to a Metal Center and Hydrides in Metal Clusters

Neutron diffraction is the method of choice when locating chemically interesting hydrogen atoms, particularly in systems containing a heavy metal. In this article, two fascinating complexes containing hydrogen atoms that were unambiguously located with neutron diffraction will be highlighted. The first complex, OsH3Cl(PPh3)3, is a Kubas-type complex containing a rare elongated dihydrogen ligand. Results from the neutron diffraction study showed that the dihydrogen ligand demonstrated an H...H distance of 1.48(2) Å. In the second study, a fourcoordinate hydrogen atom was located and measured for the first time using neutron diffraction. Results from this study showed that the hydrogen atom occupied the interstitial space of a tetrahedral yttrium (Y4) cluster.