Triruthenium dodecacarbonyl is the
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
with the formula Ru
3(CO)
12. 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 compound Organoruthenium chemistry is the chemistry of organometallic compounds containing a carbon to ruthenium chemical bond. Several organoruthenium catalysts are of commercial interest and organoruthenium compounds have been considered for cancer therapy ...
s.
Structure and synthesis
The cluster has ''D
3h''
symmetry
Symmetry () in everyday life refers to a sense of harmonious and beautiful proportion and balance. In mathematics, the term has a more precise definition and is usually used to refer to an object that is Invariant (mathematics), invariant und ...
, consisting of an
equilateral triangle
An equilateral triangle is a triangle in which all three sides have the same length, and all three angles are equal. Because of these properties, the equilateral triangle is a regular polygon, occasionally known as the regular triangle. It is the ...
of Ru atoms, each of which bears two axial and two equatorial CO ligands. The Ru-Ru distance is 284
pm.
Os3(CO)12 has the same structure. In
Fe3(CO)12, two CO ligands are
bridging, resulting in C
2v symmetry. In solution, is
fluxional as indicated by the observation of a single CO signal in the room temperature
13C NMR spectrum. The barrier is estimated at 20 kJ/mol
is prepared by treating solutions of
ruthenium trichloride
Ruthenium(III) chloride is the chemical compound with the formula RuCl3. "Ruthenium(III) chloride" more commonly refers to the hydrate RuCl3·''x''H2O. Both the anhydrous and hydrated species are dark brown or black solids. The hydrate, with a var ...
with
carbon monoxide
Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...
in the presence of a base.
Dichlororuthenium tricarbonyl dimer is an intermediate. The stoichiometry of the reaction is uncertain, one possibility being the following:
:6 RuCl
3 + 33 CO + 18 CH
3OH → 2 Ru
3(CO)
12 + 9
CO(OCH3)2 + 18 HCl
Reactions
The chemical properties of Ru
3(CO)
12 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
Ruthenium pentacarbonyl is the ruthenium compound with the formula Ru(CO)5. It is a colorless, light-sensitive liquid that readily decarbonylates upon standing at room temperature. It is of academic interest as an intermediate for the synthesi ...
, which reverts to the parent cluster upon standing.
:Ru
3(CO)
12 + 3 CO 3 Ru(CO)
5 K
eq = 3.3 x 10
−7 mol dm
−3 at room temperature
The instability of Ru(CO)
5 contrasts with the robustness of the corresponding
Fe(CO)5. The
condensation
Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor ...
of Ru(CO)
5 into Ru
3(CO)
12 proceeds via initial, rate-limiting loss of CO to give the unstable, coordinatively unsaturated species Ru(CO)
4. This tetracarbonyl binds Ru(CO)
5, initiating the condensation.
Upon warming under a pressure of
hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
, Ru
3(CO)
12 converts to the
tetrahedral
In geometry, a tetrahedron (: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular Face (geometry), faces, six straight Edge (geometry), edges, and four vertex (geometry), vertices. The tet ...
cluster H
4Ru
4(CO)
12. Ru
3(CO)
12 undergoes substitution reactions with Lewis bases:
:Ru
3(CO)
12 + ''n'' L → Ru
3(CO)
12-''n''L
''n'' + ''n'' CO (''n'' = 1, 2, or 3)
where L is a tertiary
phosphine
Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...
or an
isocyanide
An isocyanide (also called isonitrile or carbylamine) is an organic compound with the functional group –. It is the isomer of the related nitrile (–C≡N), hence the prefix is ''isocyano''.IUPAC Goldboo''isocyanides''/ref> The organic fragme ...
. It forms complexes with
acenaphthylene
Acenaphthylene, a polycyclic aromatic hydrocarbon is an ortho- and peri-fused tricyclic hydrocarbon. The molecule resembles naphthalene with positions 1 and 8 connected by a -CH=CH- unit. It is a yellow solid. Unlike many polycyclic aromatic hy ...
.
forms a variety of alkene complexes, some where the Ru3 core remains intact but often with fragmentation. Upon treatment with
1,5-cyclooctadiene
1,5-Cyclooctadiene (also known as cycloocta-1,5-diene) is a cyclic compound, cyclic hydrocarbon with the chemical formula , specifically .
There are three configurational isomers with this structure, that differ by the arrangement of the four C� ...
gives the monoRu tricarbonyl derivative:
:
Upon
irradiation with UV light, Ru
3(CO)
12 converts to an insoluble polymeric form.
Ru-carbido clusters
At high temperatures, Ru
3(CO)
12 converts to a series of clusters that contain interstitial
carbido ligands. These include Ru
6C(CO)
17 and Ru
5C(CO)
15. Anionic carbido clusters are also known, including
5C(CO)14">u5C(CO)14sup>2− and the
bioctahedral cluster
10C2(CO)24">u10C2(CO)24sup>2−.
[Nicholls, J. N.; Vargas, M. D. "Carbido-Carbonyl Ruthenium Cluster Complexes" Inorganic Syntheses, 1989, volume 26, pages 280-85. ] Ru
3(CO)
12 -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.
References
{{Carbonyl complexes
Organoruthenium compounds
Carbonyl complexes
Chemical compounds containing metal–metal bonds
Ruthenium(0) compounds