76166-14-8Relevant academic research and scientific papers
Precursor of an Extraordinarily Reactive Homogeneous Hydrogenation Catalyst. Synthesis, X-Ray Crystal Structure and Reactions of 2-3,4-CH2:CHCH2CH2)-3-H-3-PPh3-3,1,2-RhC2B9H10>
Delaney, Mark S.,Knobler, Carolyn B.,Hawthorne, M. Frederick
, p. 849 - 850 (1980)
The synthesis, X-ray crystal structure, and reactions of the catalyst precursor, the title compound (1), and the initial rates of some alkene hydrogenations catalysed by (1) are reported.
A designed metallacarborane catalyst. Synthesis, structure, and reactions of [closo-1,3-[μ-(η2-3-CH2=CHCH2CH 2)]-3-H-3-PPh3-3,1,2-RhC2B9H 10]
Delaney,Knobler,Hawthorne
, p. 1341 - 1347 (2008/10/08)
The synthesis and reactions of a designed metallacarborane catalyst, [closo-1,3-[μ-(η2-3-CH2=CHCH2CH 2)-3-H-3-PPh3-3,1,2-RhC2B9H 10] (I), are reported. Complex I contains a chelating 4-butenyl side chain attached to the dicarbollide ligand, the alkenyl function of which formally replaces one of the triphenylphosphine ligands of the parent compound [closo-3-H-3,3-(PPh3)2-3,1,2-RhC2B 9H11] (II). When I was exposed to conditions employed for the hydrogenation of alkenes or alkynes, the alkenyl ligand was hydrogenated to a noncoordinating butyl group, leaving an open coordination site on rhodium which greatly enhanced the rate of hydrogenation of added alkene. Complex I was, indeed, found to be among the most active homogeneous hydrogenation catalysts reported. Complex I also catalyzed the isomerization of hex-1-ene. The crystal and molecular structure of I has been determined by three-dimensional X-ray diffraction techniques. The compound crystallizes in the monoclinic space group P21/a with a = 16.494 (4) A?, b = 11.193 (2) A?, c = 17.006 (3) A?, β = 122.49 (1)°, and Z = 4. The observed and calculated densities are 1.229 and 1.386 g cm-3, respectively. Diffraction data to 2θ maximum = 45° (Mo Kα radiation) were collected on a Syntex P1 automated diffractometer, and the structure was solved by conventional Patterson, Fourier, and full-matrix least-squares techniques to a final discrepancy index of R = 0.044 for the 2253 independent observed reflections. All atoms, including hydrogen atoms, were located. The molecule has the closo 12-vertex icosahedral geometry, and the rhodium is bonded to one hydrogen atom and one triphenylphosphine ligand and π bonded to the alkene function as well as symmetrically bonded to the C2B3 face of the C2B9 dicarbollyl group. The molecule is monomeric, and there are no intermolecular distances shorter than van der Waals distances. The reactions of I with hydrogen in the presence and absence of triphenylphosphine are reported.
