A systematic synthetic route to ruthenium carbonyl cluster anions

Article abstract of DOI:10.1021/om50003a020

Systematic reduction of RU₃(CO)₁₂ by alkali metal-benzophenone for the preparation of ruthenium carbonyl cluster anions is described. By specifying molar ratios of Ru₃(CO)₁₂ to alkali metal-benzophenone (1:3, 1:2, 1:3/2, 1:1), stoichiometnc reactions were carried out to prepare [Ru₄(CO)₁₂]^4-, [Ru₃(CO)₁₁]^2-, [Ru₄(CO)₁₃]^2-, and [Ru₆(CO)₁₈]^2-, respectively, in high yields. The anion [Ru₄(CO)₁₂]^4- can also be prepared by the reaction of [Ru₃(CO)₁₁]^2- with 1 equiv of alkali metal-benzophenone and by the reaction of [Ru₄(CO)₁₃]^2- with 2 equiv of alkali metal-benzophenone. The anion [Ru₃(CO)₁₁]^2- reacts with 0.33 equiv of Ru₃(CO)₁₂ to give [Ru₄(CO)₁₃]^2-. This anion can react with 0.67 equiv of Ru₃(CO)₁₂ to yield [Ru₆(CO)₁₈]^2-, The latter can also be prepared directly from [Ru₃(CO)₁₁]^2- by reaction with 1 equiv of Ru₃(CO)₁₂. Also described are preparations of the conjugate acids of these anions through selective protonation reactions with HCl or HBr, and the new anion [HRu₄(CO)₁₂]^3- has been prepared. Properties of the salts prepared and infrared and NMR spectra are described.