Synthesis, Structure, and Ligand Dynamics of (m-H)( m3- h2-CH3C=NCH2CH3)Ru3(CO)9

The reaction of triethylamine with Ru3(COi)12 in refluxing hexanes catalyzed by Fe2(CO)4(SEt)2(PPh3)2 is shown to yield the complex ( m -H)RU3(CO)9(m3-h2-H=C=NCH2CH3) as the major product (30%). An X-ray crystallographic investigation of I reveals that the organic ligand is parallel to one edge of the metal triangle and acts as a five-electron donor. The hydride was located; it symmetrically bridges the two metal atoms parallel to the C-N vector and is in the plane of the metal triangle. Compound I crystallizes in the P1 space group with (Y = 8.396 (2) A, b = 15.198 (3) A, c = 8.093 (2) A, a = 102.95 (2)O, p = 108.63 (2)", and y = 90.33 (2)'. Least-squares refinement based on 2867 observed reflections led to a final R value of 3.3% (R, = 4.4%). The variable-temperature 'H and 13C NMR spectra reveal that the organic ligand is fluxional, undergoing restricted oscillatory motion which is coupled to hydride edge hopping and axial- radial exchange on two of the three ruthenium atoms.