Ruthenium
Homogeneous catalysis

Solutions containing ruthenium trichloride are highly active for olefin metathesis. Such catalysts are used commercially for the production of polynorbornene for example. Well defined ruthenium carbene and alkylidene complexes show similar reactivity but are only used on small-scale. The Grubbs' catalysts for example have been employed in the preparation of drugs and advanced materials.

Ruthenium complexes are highly active catalysts for transfer hydrogenations (sometimes referred to as "borrowing hydrogen" reactions). Chiral ruthenium complexes, introduced by Ryoji Noyori, are employed for the enantioselective hydrogenation of ketones, aldehydes, and imines. A typical catalyst is (cymene)Ru(S,S-Ts DPEN):

A Nobel Prize in Chemistry was awarded in 2001 to Ryōji Noyori for contributions to the field of asymmetric hydrogenation.
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