Triruthenium dodecacarbonyl


Triruthenium dodecacarbonyl is the chemical compound with the formula Ru312. Classified as metal carbonyl cluster, it is a dark orange-colored solid that is soluble in nonpolar organic solvents. The compound serves as a precursor to other organoruthenium compounds.

Structure and synthesis

The cluster has D3h symmetry, consisting of an equilateral triangle of Ru atoms, each of which bears two axial and two equatorial CO ligands. Os312 has the same structure, whereas Fe312 is different, with two bridging CO ligands, resulting in C2v symmetry.
Ru312 is prepared by treating solutions of ruthenium trichloride with carbon monoxide, usually under high pressure. The stoichiometry of the reaction is uncertain, one possibility being the following:

Reactions

The chemical properties of Ru312 have been widely studied, and the cluster has been converted to hundreds of derivatives. High pressures of CO convert the cluster to the monomeric ruthenium pentacarbonyl, which reverts to the parent cluster upon standing.
The instability of Ru5 contrasts with the robustness of the corresponding Fe5. The condensation of Ru5 into Ru312 proceeds via initial, rate-limiting loss of CO to give the unstable, coordinatively unsaturated species Ru4. This tetracarbonyl binds Ru5, initiating the condensation.
Upon warming under a pressure of hydrogen, Ru312 converts to the tetrahedral cluster H4Ru412. Ru312 undergoes substitution reactions with Lewis bases:
where L is a tertiary phosphine or an isocyanide. It forms complexes with acenaphthylene.

Ru-carbido clusters

At high temperatures, Ru312 converts to a series of clusters that contain interstitial carbido ligands. These include Ru6C17 and Ru5C15. Anionic carbido clusters are also known, including 2− and the bioctahedral cluster 2−. Ru312 -derived carbido compounds have been used to synthesize nanoparticles for catalysis. These particles consist of 6-7 atoms and thus are all surface, resulting in extraordinary activity.