Decacarbonyldihydridotriosmium is an
organoosmium compound with the formula H
2Os
3(CO)
10. This purple-violet
crystalline
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...
air-stable cluster is noteworthy because it is
electron-deficient
In chemistry, electron deficiency (and electron-deficient) is jargon that is used in two contexts: chemical species that violate the octet rule because they have too few valence electrons and species that happen to follow the octet rule but have el ...
and hence adds a variety of substrates.
Structure and synthesis
The trinuclear cluster features an isosceles triangular array of metals with one short edge (''r''
Os-Os = 2.68 Å), which is spanned by the two hydride ligands, and two longer edges (r
Os-Os = 2.81 Å). It can be described as Os(CO)
4 s(CO)3(μ-H)sub>2. The bonding in the Os
2H
2 subunit has been compared to the
3-center, 2e bonding in
diborane
Diborane(6), commonly known as diborane, is the chemical compound with the formula . It is a highly toxic, colorless, and pyrophoric gas with a repulsively sweet odor. Given its simple formula, borane is a fundamental boron compound. It has att ...
. The molecule forms a variety of adducts with loss of H
2.
It is prepared by purging a solution of
Os3(CO)12 in
octane
Octane is a hydrocarbon and also an alkane with the chemical formula C8H18, and the condensed structural formula CH3(CH2)6CH3. Octane has many structural isomers that differ by the location of branching in the carbon chain. One of these isomers ...
(or other inert solvent of similar boiling point) with
H2.
:Os
3(CO)
12 + H
2 → Os
3H
2(CO)
10 + 2 CO
Reactions
The cluster reacts with a wide range of reagents under mild conditions. Illustrative is its reaction with
diazomethane
Diazomethane is an organic chemical compound with the formula CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow ga ...
to give Os
3(CO)
10(μ-H)(μ-CH
3), exhibiting an
agostic interaction
In organometallic chemistry, agostic interaction refers to the intramolecular interaction of a coordinatively-unsaturated transition metal with an appropriately situated C−H bond on one of its ligands. The interaction is the result of two ele ...
, the first identified in a metal cluster.
References
{{Osmium compounds
Organoosmium compounds
Carbonyl complexes
Hydrido complexes
Chemical compounds containing metal–metal bonds