The ruthenium aqua complexes [cp* Ru (OH2)(N–N)](OTf)(cp*= η5- pentamethylcyclopentadienyl, N–N= 2, 2′-bipyridine, phen= 1, 10-phenanthroline, OTf−= trifluoromethanesulfonate) and the acetonitrile complex [cpRu (CH3CN)(bipy)](OTf)(cp= η5- cyclopentadienyl) are water-, acid-, and thermally stable (> 200° C) catalysts for the hydrogenation of aldehydes and ketones in sulfolane solution. In the presence of HOTf as ...