Reactions of a Transient Carbonyl(chloro)(hydrido)ruthenium(II) Complex with Ethylene, Alkynes, and CO; Chemistry of the New Anion [Ru2(CO)4Cl5]−

A 97% yield of [Ru3(CO)12] (2) in 20 minutes is obtained simply by treating [Ru(CO)3Cl2(thf)] with KOH under CO (1 atm). The reduction to Ru0 can be explained in terms of the facile reductive elimination of HCl from the transient hydrido complex 1. Though elusive, the latter can be intercepted by olefins or alkynes to produce trappable alkyl or alkenyl complexes such as 3 and 4.█ denotes a vacant coordination site.