Amidinatogermylene Derivatives of Ruthenium Carbonyl: New Insights into the Reactivity of [Ru₃(CO)₁₂] with Two-Electron-Donor Reagents of High Basicity

Abstract

The reactivity of ruthenium carbonyl with amidinatogermylenes of the type Ge(R2bzam)(t)Bu (R2bzam = N,N'-disubstituted benzamidinate) was studied for R = (t)Bu (1tBu) and (i)Pr (1iPr). The mono-, bi-, and/or trinuclear derivatives [Ru(1R)(CO)4], [Ru(1R)2(CO)3], [Ru2(1iPr)(CO)7], [Ru3(1tBu)(CO)11], [Ru3(1tBu)2(CO)10], and [Ru3(1R)3(CO)9] (R = (t)Bu, (i)Pr) were isolated in yields that depend upon the reactant ratio and the reaction temperature. The experimental data are consistent with the proposal that, at room temperature, the trinuclear complexes [Ru3(CO)12], [Ru3(1R)(CO)11], and [Ru3(1R)2(CO)10] form an adduct with the germylene 1R that may evolve through two different reaction pathways, (a) releasing a CO ligand (thus leading to the corresponding trinuclear CO-substituted product) and/or (b) cleaving the cluster framework (thus leading to mononuclear germylene-containing products). At 90 °C, additional processes are also possible, such as the reactions of 1R with [Ru(1R)(CO)4] or [Ru3(1R)3(CO)9], which both give [Ru(1R)2(CO)3], or the reactions of [Ru(1tBu)(CO)4] and [Ru(1iPr)(CO)4] with [Ru3(CO)12], which give [Ru3(1tBu)(CO)11] and [Ru2(1iPr)(CO)7], respectively. This wide reaction panorama helps rationalize previously reported outcomes of reactions of [Ru3(CO)12] with other reagents of high basicity, such as trialkylphosphines or N-heterocyclic carbenes, including results for which no satisfactory explanation has been hitherto provided.