Takahashi, Yoshiaki Akita, Munetaka Hikichi, Shiro Moro-oka, Yoshihiko Two Isomeric Structures of Hydridoruthenium Complexes Supported by Hydrotrispyrazolylborates, Tp<sup>R</sup>Ru(H)(1,5-cyclooctadiene):  An Octahedral Structure with Additional 3-Center-2-Electron Ru−H−B Interaction Is More Stable than a Square-Pyramidal Structure with a κ<sup>2</sup>-Tp<sup>R</sup> Ligand Hydrido-cod-ruthenium complexes containing hydrotris(3,5-diisopropylpyrazolyl)borate (Tp<sup>iPr</sup>) and its 4-brominated derivative (Tp<sup>iPrBr</sup>), Tp<sup>R</sup>Ru(H)(cod), are reported. Spectroscopic and crystallographic analyses reveal the presence of two isomeric structures, a square-pyramidal structure with a κ<sup>2</sup>-Tp<sup>R</sup> ligand and an octahedral structure with an additional 3-center-2-electron Ru−H−B interaction, and isomerization from the former structure to the latter structure is observed for the first time by means of <sup>1</sup>H NMR analyses. Ru;κ 2;Tp R ligand;1 H NMR analyses 1998-10-08
    https://acs.figshare.com/articles/journal_contribution/Two_Isomeric_Structures_of_Hydridoruthenium_Complexes_Supported_by_Hydrotrispyrazolylborates_Tp_sup_R_sup_Ru_H_1_5-cyclooctadiene_An_Octahedral_Structure_with_Additional_3-Center-2-Electron_Ru_H_B_Interaction_Is_More_Stable_than_a_Square-Pyramidal_Structu/3782595
10.1021/om980363w.s001