Probing the non-classical dihydrogen ligand in OsClH3(PPh3)3 using X-ray and neutron diffraction, inelastic neutron scattering, and theoretical calculations

Published

February 15, 2022

Author(s)

Carly Carter, Ryan Klein, Wei Zhou, Terrence J. Udovic, Craig Brown, Ting-Bin Wen, Thomas Cundari, Muhammed Yousufuddin

Abstract

: Dihydrogen ligation to metal centers results in a wide range of metal-hydrogen interactions. Compounds containing non-classical dihydrogen ligands in which the H–H contacts are significantly longer than the 0.74 Å distance found in solid H2 are classified as Kubas-like compounds, stretched dihydrogen ligands, or compressed dihydrides, depending on the H–H contact length. Compounds containing stretched dihydrogen and compressed dihydride ligands are somewhat rare. Developing a more complete understanding of the metal-hydrogen and hydrogen-hydrogen interactions in these species may provide insights into the mechanisms for the oxidative addition reaction and hydrogen storage. Here, we use diffraction and inelastic neutron scattering (INS) measurements, paired with density functional theory (DFT) calculations, to fully characterize the nature of the metal-hydrogen and hydrogen-hydrogen interactions in a previously reported compound, OsClH3(PPh3)3. The INS-generated phonon density of states is well described by the DFT calculations, including those normal modes dominated by the vibrational motions of the three Os-ligated hydrogen atoms. The close agreement between theory and experiment corroborates the validity of the DFT functionals used to describe the system. The resulting calculated electron charge density landscape indicates that there is no remnant bonding character between the Os-ligated hydrogen atoms in the compound. Based on these findings, we update the understanding of the metal-hydrogen bonding in this complex and reclassify it as a compressed dihydride. As such, OsClH3(PPh3)3 represents a rare example of a non-classical compressed dihydride species.

Citation

Journal of Alloys and Compounds

Volume

894

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.jallcom.2021.162445

Local Download

Keywords

hydrogen storage, molecular polyhydride

Citation

Carter, C. , Klein, R. , Zhou, W. , Udovic, T. , Brown, C. , Wen, T. , Cundari, T. and Yousufuddin, M. (2022), Probing the non-classical dihydrogen ligand in OsClH3(PPh3)3 using X-ray and neutron diffraction, inelastic neutron scattering, and theoretical calculations, Journal of Alloys and Compounds, [online], https://doi.org/10.1016/j.jallcom.2021.162445, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932862 (Accessed April 28, 2024)