Cyclooctadiene rhodium chloride dimer is the
organorhodium compound Organorhodium chemistry is the chemistry of organometallic compounds containing a rhodium-carbon chemical bond, and the study of rhodium and rhodium compounds as catalysts in organic reactions.
Stable organorhodium compounds and transient organor ...
with the formula Rh
2Cl
2(C
8H
12)
2, commonly abbreviated
hCl(COD) HCL may refer to:
Science and medicine
* Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia
* Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development
* Hollow-cathode lamp, a spe ...
sub>2 or Rh
2Cl
2(COD)
2. This yellow-orange, air-stable compound is a widely used precursor to
homogeneous catalysts.
[Giordano, G.; Crabtree, R. H. “Di-μ-chloro-bis(η4-1,5-cyclooctadiene)dirhodium(I)” Inorganic Syntheses, 1990, volume 28, pages 88-90. ]
Preparation and reactions
The synthesis of
hCl(COD) HCL may refer to:
Science and medicine
* Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia
* Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development
* Hollow-cathode lamp, a spe ...
sub>2 involves heating a solution of hydrated
rhodium trichloride
Rhodium(III) chloride refers to inorganic compounds with the formula RhCl3(H2O)''n'', where ''n'' varies from 0 to 3. These are diamagnetic solids featuring octahedral Rh(III) centres. Depending on the value of ''n'', the material is either a de ...
with
1,5-cyclooctadiene
Cycloocta-1,5-diene is a cyclic hydrocarbon with the chemical formula , specifically .
There are three configurational isomers with this structure, that differ by the arrangement of the four C–C single bonds adjacent to the double bonds. Each ...
in aqueous
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...
in the presence of
sodium carbonate
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
:
:2 RhCl
3·3H
2O + 2 COD + 2 CH
3CH
2OH + 2 Na
2CO
3 →
hCl(COD) HCL may refer to:
Science and medicine
* Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia
* Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development
* Hollow-cathode lamp, a spe ...
sub>2 + 2
CH3CHO + 8 H
2O + 2 CO
2 + 4 NaCl
hCl(COD) HCL may refer to:
Science and medicine
* Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia
* Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development
* Hollow-cathode lamp, a spe ...
sub>2 is principally used as a source of the
electrophile "
h(COD)sup>+."
:
hCl(COD) HCL may refer to:
Science and medicine
* Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia
* Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development
* Hollow-cathode lamp, a spe ...
sub>2 + L →
Rh(COD)">Rh(COD)sup>+Cl
− (where L = PR
3, alkene, etc. and = 2 or 3)
In this way,
chiral phosphines can be attached to Rh. The resulting chiral complexes are capable of
asymmetric hydrogenation. A related but still more reactive complex is
chlorobis(cyclooctene)rhodium dimer. The dimer reacts with a variety of Lewis bases (L) to form adducts with the stoichiometry RhCl(L)(COD).
Structure
The molecule consists of a pair of square planar Rh centers bound to a
1,5-cyclooctadiene
Cycloocta-1,5-diene is a cyclic hydrocarbon with the chemical formula , specifically .
There are three configurational isomers with this structure, that differ by the arrangement of the four C–C single bonds adjacent to the double bonds. Each ...
and two chloride ligands that are
shared between the Rh centers. The Rh
2Cl
2 core is also approximately planar,
["Di-μ-chloro-bis cis,cis-η4-1,5-cyclooctadiene)rhodium(I) a redetermination" De Ridder, Kirk J. A. Acta Crystallographica, Section C: Crystal Structure Communications 1994, C50, 1569-72. ] in contrast to the highly bent structure of
cyclooctadiene iridium chloride dimer
Cyclooctadiene iridium chloride dimer is an organoiridium compound with the formula r(μ2-Cl)(COD)sub>2, where COD is the diene 1,5-cyclooctadiene (C8H12). It is an orange-red solid that is soluble in organic solvents. The complex is used as a ...
where the dihedral angle is 86°.
References
External links
*
{{Rhodium compounds
Organorhodium compounds
Homogeneous catalysis
Cyclooctadiene complexes
Dimers (chemistry)
Chloro complexes
Rhodium(I) compounds