ja049402n_si_003.pdf (1.62 MB)

[(iPr3P)6Rh6H12]2+:  A High-Hydride Content Octahedron that Bridges the Gap between Late and Early Transition Metal Clusters

Download (1.62 MB)
journal contribution
posted on 21.04.2004, 00:00 by Michael J. Ingleson, Mary F. Mahon, Paul R. Raithby, Andrew S. Weller
Treatment of [(iPr3P)2Rh(nbd)][Y] {nbd = norbornadiene, Y = B{3,5-(CF3)2C6H3}4- [B(ArF)4] or 1-H-closo-CB11Me11-} with H2 (ca. 4 atm) results in the isolation, in moderate yield, of the octahedral cluster complex [(iPr3P)6Rh6H12][Y]2 1. The cluster (for both anions) has been characterized by NMR, mass spectroscopy, and X-ray crystallography. These show 1 to have 12 edge-bridging hydrogen atoms, and the structure bears more resemblance to clusters of the early transition metals with π-donor ligands than those of the late transition metals with π-acceptor ligands. Intermediate complexes on the route to 1, namely, the nonclassical dihydrogen complexes [(iPr3P)2Rh(H)22-H2)x][B(ArF)4] (x = 1 or 2), have been observed spectroscopically. The high hydride content of 1 makes it a possible model for nanocluster colloidal Rh(0) catalysts that are used in olefin and arene hydrogenation.