Direct Comparison of Hydrogenation Catalysis by Intact versus Fragmented Triruthenium Clusters D.B. acknowledges financial support from the ORS Award Scheme. S.B.D. is grateful to the EPSRC, the JREI Scheme, and Bruker UK for financial support. P.J.D. thanks the Royal Society for a University Research Fellowship. Discussions with Prof. R. Eisenberg (NATO support), Prof. B. F. G. Johnson, Prof. R. N. Perutz, and Dr. R. J. Mawby are gratefully acknowledged.