Methylidynetricobaltnonacarbonyl is the
organocobalt compound
Organocobalt chemistry is the chemistry of organometallic compounds containing a carbon to cobalt chemical bond. Organocobalt compounds are involved in several organic reactions and the important biomolecule vitamin B12 has a cobalt-carbon bond. ...
with the formula HCCo
3(CO)
9. It is a metal carbonyl
cluster
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that contains the
methylidyne ligand. The compound has C
3v point group symmetry
In group theory, the symmetry group of a geometric object is the group of all transformations under which the object is invariant, endowed with the group operation of composition. Such a transformation is an invertible mapping of the ambient ...
. It is a purple, air-stable solid that is soluble in some organic solvents, but not in water.
The compound is prepared by the reaction of
dicobalt octacarbonyl
Dicobalt octacarbonyl is an organocobalt compound with composition . This metal carbonyl is used as a reagent and catalyst in organometallic chemistry and organic synthesis, and is central to much known organocobalt chemistry. It is the parent me ...
with
bromoform
Bromoform (CHBr3) is a brominated organic solvent, colorless liquid at room temperature, with a high refractive index, very high density, and sweet odor is similar to that of chloroform. It is one of the four haloforms, the others being fluoroform, ...
. Much of the cobalt(0) is consumed in the formation of
cobalt(II) bromide. An idealized equation for the synthesis is:
:9 Co
2(CO)
8 + 4 CHBr
3 → 4 HCCo
3(CO)
9 + 36 CO + 6 CoBr
2
Many analogues are known, including the
benzylidyne,
arsinidyne, and
chloromethylidyne derivatives, respectively ,
, and . The potential of some analogues as
catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
s for
hydroformylation
Hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes from alkenes. This chemical reaction entails the net addition of a formyl group (CHO) and a hydrogen atom to a carbon-carbon d ...
– including with acylidyne and arylidyne
moieties – has been investigated.
The structure has been analyzed by
X-ray crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
. The Co-Co distances are near 2.48 Å in length. The compound is structurally related to
tetracobalt dodecacarbonyl
Tetracobalt dodecacarbonyl is the chemical compound with the formula Co4(CO)12. It is a black crystalline compound that is insoluble in water and easily oxidized by air. It is an example of a metal carbonyl cluster.
Synthesis and structure
This co ...
.
[{{cite journal, journal = Acta Crystallogr. B, year = 1981, volume = 37, issue = 7, pages = 1347–1352, doi = 10.1107/S0567740881005906, title = The Structure of Nonacarbonyl-μ3-methylidyne-''triangulo''-tricobalt. X-ray and Neutron Diffraction Studies, first1 = P., last1 = Leung, first2 = P., last2 = Coppens, first3 = R. K., last3 = McMullan, first4 = T. F., last4 = Koetzle]
References
Organocobalt compounds
Carbonyl complexes