Method and conditions of preparation strongly affect the hydroformylation activity of the ruthenium cluster derived Ru 3 (CO) 1 2 /2,2 -bipyridine/SiO 2 catalyst. The highest activities have been achieved with a dichloromethane impregnated catalyst. A major problem with this catalyst is poor reproducibility of the hydroformylation activity, probably due to uncontrolled formation of several supported surface species. Reproducibility can be improved by using a non-chlorinated impregnation solvent such as tetrahydrofurane. In hydroformylation, Ru 3 (CO) 1 2 /2,2 -bipyridine/SiO 2 has a strong tendency to convert alkenes directly to alcohols. The limiting step in this process is the initial hydrocarbonylation of alkenes to aldehydes. Ru 3 (CO) 1 2 /2,2 -bipyridine/SiO 2 catalyzes the second step, hydrogenation of aldehydes to alcohols, in good yield. Use of an effective, aldehydeproducing cocatalyst such as Rh together with Ru 3 (CO) 1 2 /2,2 -bipyridine/SiO 2 allows very high alcohol yields to be achieved. The detailed surface structure of Ru 3 (CO) 1 2 /2,2 -bipyridine/SiO 2 is not known, but one probable active species is oligomeric or polymeric [{Ru(bpy)(CO) 2 } n ]. Monomeric and dimeric ruthenium monobipyridines showed at most only moderate activity in hydroformylation. By contrast, [Ru(bpy)(CO) 2 Cl(C(O)OCH 3 )] and [Ru(bpy)(CO) 2 ClH] are highly active in hydrogenation of C 7 aldehydes to C 7 alcohols.