Synthesis of Hydrido−Vinylidene and Hydrido−Carbyne Osmium Complexes Containing Pyrazole: New Examples of N−H···Y (Y = N, F, Cl) Hydrogen Bonds

Abstract

The hydrido−carbyne complex OsHCl2(⋮CCH2Ph)(PiPr3)2 (1) reacts with pyrazole in the presence of KOH to afford the six-coordinate hydrido−vinylidene OsH(pz)(CCHPh)(Hpz)(PiPr3)2 (2). The structure of 2 in the solid state has been determined by an X-ray diffraction study. The geometry around the metal center could be described as a distorted octahedron with the two phosphorus atoms of the phosphines occupying apical positions. The equatorial plane is defined by the hydride, the vinylidene, the pyrazole, and the pyrazolato ligands. The N−H hydrogen atom of the pyrazole lies between this azole group and the pyrazolate, forming an intramolecular N···H···N hydrogen bond. Reaction of 2 with HBF4 leads to the fluoro−carbyne derivative [OsHF(⋮CCH2Ph)(Hpz)(PiPr3)2]BF4 (3), whose structure has been determined by an X-ray diffraction study. The geometry around the metal center could be also described as a distorted octahedron with the two phosphorus atoms of the phosphines occupying apical positions. The equatorial pl...