Cyclooctadiene rhodium chloride dimer

Last updated
Cyclooctadiene rhodium chloride dimer
Cyclooctadiene-rhodium-chloride-dimer-2D-skeletal.png
Cyclooctadiene-rhodium-chloride-dimer-3D-balls.png
Names
IUPAC name
di-μ-chlorido-bis[η22-(cycloocta-1,5-diene)rhodium]
Other names
Cyclooctadiene rhodium chloride dimer
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.949 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 235-157-6
PubChem CID
  • InChI=1S/2C8H12.2ClH.2Rh/c2*1-2-4-6-8-7-5-3-1;;;;/h2*1-2,7-8H,3-6H2;2*1H;;/q;;;;2*+1/p-2/b2*2-1-,8-7-;;;; Yes check.svgY
    Key: QSUDXYGZLAJAQU-MIXQCLKLSA-L Yes check.svgY
  • InChI=1/2C8H12.2ClH.2Rh/c2*1-2-4-6-8-7-5-3-1;;;;/h2*1-2,7-8H,3-6H2;2*1H;;/q;;;;2*+1/p-2/b2*2-1-,8-7-;;;;/r2C8H12.2ClRh/c2*1-2-4-6-8-7-5-3-1;2*1-2/h2*1-2,7-8H,3-6H2;;/b2*2-1-,8-7-;;
    Key: QSUDXYGZLAJAQU-PXXGERDABU
  • Cl1[Rh]Cl[Rh]1.C=1CC\C=C/CCC=1.C/1C\C=C/CC\C=C\1
Properties
C16H24Cl2Rh2
Molar mass 493.0806 g/mol
Density 1.93 g/cm3
Melting point 243 °C (469 °F; 516 K)
Solubility dichloromethane
Hazards
GHS labelling:
GHS-pictogram-exclam.svg GHS-pictogram-pollu.svg
Warning
H302, H315, H317, H319, H335, H411
P261, P264, P270, P271, P272, P273, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P391, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Cyclooctadiene rhodium chloride dimer is the organorhodium compound with the formula Rh2Cl2(C8H12)2, commonly abbreviated [RhCl(COD)]2 or Rh2Cl2(COD)2. This yellow-orange, air-stable compound is a widely used precursor to homogeneous catalysts. [1]

Contents

Preparation and reactions

The synthesis of [RhCl(COD)]2 involves heating a solution of hydrated rhodium trichloride with 1,5-cyclooctadiene in aqueous ethanol in the presence of sodium carbonate: [1] [2]

2 RhCl3·3H2O + 2 COD + 2 CH3CH2OH + 2 Na2CO3 → [RhCl(COD)]2 + 2 CH3CHO + 8 H2O + 2 CO2 + 4 NaCl

[RhCl(COD)]2 is principally used as a source of the electrophile "[Rh(COD)]+."

[RhCl(COD)]2 + nL → [LnRh(COD)]+Cl (where L = PR3, alkene, etc. and n = 2 or 3)

In this way, chiral phosphines can be attached to Rh. The resulting chiral complexes are capable of asymmetric hydrogenation. [3] 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 and two chloride ligands that are shared between the Rh centers. The Rh2Cl2 core is also approximately planar, [4] in contrast to the highly bent structure of cyclooctadiene iridium chloride dimer where the dihedral angle is 86°.

Related Research Articles

<span class="mw-page-title-main">Diene</span> Covalent compound that contains two double bonds

In organic chemistry, a diene ; also diolefin, dy-OH-lə-fin) or alkadiene) is a covalent compound that contains two double bonds, usually among carbon atoms. They thus contain two alkene units, with the standard prefix di of systematic nomenclature. As a subunit of more complex molecules, dienes occur in naturally occurring and synthetic chemicals and are used in organic synthesis. Conjugated dienes are widely used as monomers in the polymer industry. Polyunsaturated fats are of interest to nutrition.

<span class="mw-page-title-main">Wilkinson's catalyst</span> Chemical compound

Wilkinson's catalyst (chlorido­tris(triphenylphosphene)­rhodium(I)) is a coordination complex of rhodium with the formula [RhCl(PPh3)3], where 'Ph' denotes a phenyl group. It is a red-brown colored solid that is soluble in hydrocarbon solvents such as benzene, and more so in tetrahydrofuran or chlorinated solvents such as dichloromethane. The compound is widely used as a catalyst for hydrogenation of alkenes. It is named after chemist and Nobel laureate Sir Geoffrey Wilkinson, who first popularized its use.

<span class="mw-page-title-main">Rhodium(III) chloride</span> Chemical compound

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 dense brown solid or a soluble reddish salt. The soluble trihydrated (n = 3) salt is widely used to prepare compounds used in homogeneous catalysis, notably for the industrial production of acetic acid and hydroformylation.

<span class="mw-page-title-main">Iridium(III) chloride</span> Chemical compound

Iridium(III) chloride is the inorganic compound with the formula IrCl3. The anhydrous compound is relatively rare, but the related hydrate is much more commonly encountered. The anhydrous salt has two polymorphs, α and β, which are brown and red colored respectively. More commonly encountered is the hygroscopic dark green trihydrate IrCl3(H2O)3 which is a common starting point for iridium chemistry.

<span class="mw-page-title-main">Crabtree's catalyst</span> Chemical compound

Crabtree's catalyst is an organoiridium compound with the formula [C8H12IrP(C6H11)3C5H5N]PF6. It is a homogeneous catalyst for hydrogenation and hydrogen-transfer reactions, developed by Robert H. Crabtree. This air stable orange solid is commercially available and known for its directed hydrogenation to give trans stereoselectivity with respective of directing group.

Cycloocta-1,5-diene is a cyclic hydrocarbon with the chemical formula C8H12, specifically [−(CH2)2−CH=CH−]2.

Martin Arthur Bennett FRS is an Australian inorganic chemist. He gained recognition for studies on the co-ordination chemistry of tertiary phosphines, olefins, and acetylenes, and the relationship of their behaviour to homogeneous catalysis.

<span class="mw-page-title-main">Organoiridium chemistry</span> Chemistry of organometallic compounds containing an iridium-carbon bond

Organoiridium chemistry is the chemistry of organometallic compounds containing an iridium-carbon chemical bond. Organoiridium compounds are relevant to many important processes including olefin hydrogenation and the industrial synthesis of acetic acid. They are also of great academic interest because of the diversity of the reactions and their relevance to the synthesis of fine chemicals.

Cyclodiphosphazanes are saturated four membered P2N2 ring systems and one of the major classes of cyclic phosphazene compounds. Bis(chloro)cyclodiphosphazanes, (cis-[ClP(μ-NR)]2) are important starting compounds for synthesizing a variety of cyclodiphosphazane derivatives by nucleophilic substitution reactions; are prepared by reaction of phosphorus trichloride (PCl3) with a primary amine (RNH2) or amine hydrochlorides (RNH3Cl).

<span class="mw-page-title-main">Organorhodium chemistry</span> Field of study

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.

In chemistry, metal-catalysed hydroboration is a reaction used in organic synthesis. It is one of several examples of homogeneous catalysis.

<span class="mw-page-title-main">Metal-phosphine complex</span>

A metal-phosphine complex is a coordination complex containing one or more phosphine ligands. Almost always, the phosphine is an organophosphine of the type R3P (R = alkyl, aryl). Metal phosphine complexes are useful in homogeneous catalysis. Prominent examples of metal phosphine complexes include Wilkinson's catalyst (Rh(PPh3)3Cl), Grubbs' catalyst, and tetrakis(triphenylphosphine)palladium(0).

<span class="mw-page-title-main">Pentamethylcyclopentadienyl ruthenium dichloride dimer</span> Chemical compound

Pentamethylcyclopentadienyl ruthenium dichloride is an organoruthenium chemistry with the formula [(C5(CH3)5)RuCl2]2, commonly abbreviated [Cp*RuCl2]2. This brown paramagnetic solid is a reagent in organometallic chemistry. It is an unusual example of a compound that exists as isomers that differ in the intermetallic separation, a difference that is manifested in a number of physical properties.

<span class="mw-page-title-main">Cyclooctadiene iridium chloride dimer</span> Chemical compound

Cyclooctadiene iridium chloride dimer is an organoiridium compound with the formula [Ir(μ2-Cl)(COD)]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 precursor to other iridium complexes, some of which are used in homogeneous catalysis. The solid is air-stable but its solutions degrade in air.

<span class="mw-page-title-main">Chlorobis(cyclooctene)rhodium dimer</span> Chemical compound

Chlorobis(cyclooctene)rhodium dimer is an organorhodium compound with the formula Rh2Cl2(C8H14)4, where C8H14 is cis-cyclooctene. Sometimes abbreviated Rh2Cl2(coe)4, it is a red-brown, air-sensitive solid that is a precursor to many other organorhodium compounds and catalysts.

<span class="mw-page-title-main">Chlorobis(ethylene)rhodium dimer</span> Chemical compound

Chlorobis(ethylene)rhodium dimer is an organorhodium compound with the formula Rh2Cl2(C2H4)4. It is a red-orange solid that is soluble in nonpolar organic solvents. The molecule consists of two bridging chloride ligands and four ethylene ligands. The ethylene ligands are labile and readily displaced even by other alkenes. A variety of homogeneous catalysts have been prepared from this complex.

<span class="mw-page-title-main">Rhodium carbonyl chloride</span> Chemical compound

Rhodium carbonyl chloride is an organorhodium compound with the formula Rh2Cl2(CO)4. It is a red-brown volatile solid that is soluble in nonpolar organic solvents. It is a precursor to other rhodium carbonyl complexes, some of which are useful in homogeneous catalysis.

<span class="mw-page-title-main">Pentamethylcyclopentadienyl rhodium dichloride dimer</span> Chemical compound

Pentamethylcyclopentadienyl rhodium dichloride dimer is an organometallic compound with the formula [(C5(CH3)5RhCl2)]2, commonly abbreviated [Cp*RhCl2]2 This dark red air-stable diamagnetic solid is a reagent in organometallic chemistry.

<span class="mw-page-title-main">Bis(triphenylphosphine)rhodium carbonyl chloride</span> Chemical compound

Bis(triphenylphosphine)rhodium carbonyl chloride is the organorhodium complex with the formula [RhCl(CO)(PPh3)2]. This complex of rhodium(I) is a bright yellow, air-stable solid. It is the Rh analogue of Vaska's complex, the corresponding iridium complex. With regards to its structure, the complex is square planar with mutually trans triphenylphosphine (PPh3) ligands. The complex is a versatile homogeneous catalyst.

<span class="mw-page-title-main">Cyclooctadiene iridium methoxide dimer</span> Chemical compound

Cyclooctadiene iridium methoxide dimer is an organoiridium compound with the formula Ir2(OCH3)2(C8H12)2, where C8H12 is the diene 1,5-cyclooctadiene. It is a yellow solid that is soluble in organic solvents. The complex is used as a precursor to other iridium complexes, some of which are used in homogeneous catalysis.

References

  1. 1 2 Giordano, G.; Crabtree, R. H. "Di-μ-chloro-bis(η4-1,5-cyclooctadiene)dirhodium(I)" Inorganic Syntheses, 1990, volume 28, pages 88-90. doi : 10.1002/9780470132593.ch22
  2. Chatt, J.; Venanzi, L. M. (1956). "Olefin Complexes of Rhodium". Nature. 177 (4514): 852–3. Bibcode:1956Natur.177..852C. doi:10.1038/177852b0. S2CID   4296682.
  3. W. S. Knowles (2003). "Asymmetric Hydrogenations (Nobel Lecture 2001)". Advanced Synthesis & Catalysis. 345 (1–2): 3–13. doi:10.1002/adsc.200390028.
  4. "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. doi : 10.1107/S0108270194001459