Cyclooctadiene iridium chloride dimer

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Cyclooctadiene iridium chloride dimer
Ir2Cl2 cod 2improved.svg
Cyclooctadiene-iridium-chloride-dimer-from-xtal-3D-bs-17.png
Ir2Cl2(cod)2.jpg
Names
Other names
Bis(1,5-cyclooctadiene)diiridium(I) dichloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.961 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 235-170-7
PubChem CID
  • 5365616  PubChem has wrong formula
  • C1/C=C\CC/C=C\C1.C1/C=C\CC/C=C\C1.[Cl].[Cl].[Ir].[Ir]
Properties
C16H24Cl2Ir2
Molar mass 671.70
Appearancered-orange solid
Density 2.65 g/cm3 (red polymorph)
Hazards
GHS labelling:
GHS-pictogram-exclam.svg
Warning
H302, H312, H315, H319, H335
P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P322, P330, P332+P313, P337+P313, P362, P363, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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. [1] The solid is air-stable but its solutions degrade in air.

Contents

Preparation, structure, reactions

The compound is prepared by heating hydrated iridium trichloride and cyclooctadiene in alcohol solvent. In the process, Ir(III) is reduced to Ir(I). [2]

In terms of its molecular structure, the iridium centers are square planar as is typical for a d8 complex. The Ir2Cl2 core is folded with a dihedral angle of 86°. The molecule crystallizes in yellow-orange and red-orange polymorphs; the latter one is more common. [3] [4]

The complex is widely used precursor to other iridium complexes. A notable derivative is Crabtree's catalyst. [5] The chloride ligands can also be replaced with methoxide to give cyclooctadiene iridium methoxide dimer, Ir2(OCH3)2(C8H12)2. [6] The cyclooctadiene ligand is prone to isomerize in cationic complexes of the type [(C8H12)IrL2]+. [7]

See also

Related Research Articles

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

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

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

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

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

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

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

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

Chlorobis(cyclooctene)iridium dimer is an organoiridium compound with the formula Ir2Cl2(C8H14)4, where C8H14 is cis-cyclooctene. Sometimes abbreviated Ir2Cl2(coe)4, it is a yellow, air-sensitive solid that is used as a precursor to many other organoiridium 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">Transition-metal allyl complex</span>

Transition-metal allyl complexes are coordination complexes with allyl and its derivatives as ligands. Allyl is the radical with the connectivity CH2CHCH2, although as a ligand it is usually viewed as an allyl anion CH2=CH−CH2, which is usually described as two equivalent resonance structures.

<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.

<span class="mw-page-title-main">Transition metal acyl complexes</span>

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References

  1. J. Hartwig, "Organotransition Metal Chemistry: From Bonding to Catalysis" University Science Books, 2009. ISBN   978-1891389535.
  2. Herdé, J. L.; Lambert, J. C.; Senoff, C. V. (1974). "Cyclooctene and 1,5-Cyclooctadiene Complexes of Iridium(I)". Inorganic Syntheses. Inorganic Syntheses. Vol. 15. p. 18–20. doi:10.1002/9780470132463.ch5. ISBN   9780470132463.
  3. F. Albert Cotton, Pascual Lahuerta, Mercedes Sanau, Willi Schwotzer "Air oxidation of Ir2(Cl)2(COD)2 revisited. The structures of [Ir(μ2-Cl)(COD)]2 (ruby form) and its oxidation product, Ir2Cl2(COD)22-OH)22-O)" Inorganica Chimica Acta, 1986 vol. 120, Pages 153–157. doi : 10.1016/S0020-1693(00)86102-2
  4. Tabrizi, D., Manoli, J. M., Dereigne, A., "Etude radiocristallographique de μ-dichloro-bis (π cyclooctadiène-1,5) diiridium: [(COD-1,5)IrCl]2, variété jaune-orange", Journal of the Less Common Metals 1970, vol. 21, pp. 337. doi : 10.1016/0022-5088(70)90155-4
  5. Crabtree, Robert H.; Morehouse, Sheila M. (1986). "[η4 -1,5-Cyclooctadiene)(Pyridine)-(Tricyclohexylphosphine)Iridium(I)Hexafluorophosphate". 4-1,5-Cyclooctadiene)(Pyridine)(Tricyclohexylphosphine)Iridium(I)Hexafluorophosphate. Inorganic Syntheses. Vol. 24. p. 173–176. doi:10.1002/9780470132555.ch50. ISBN   9780470132555.
  6. Uson, R.; Oro, L. A.; Cabeza, J. A. (1985). Dinuclear Methoxy, Cyclooctadiene, and Barrelene Complexes of Rhodium(I) and Iridium(I). Inorganic Syntheses. Vol. 23. pp. 126–130. doi:10.1002/9780470132548.ch25. ISBN   9780470132548.
  7. Martín, Marta; Sola, Eduardo; Torres, Olga; Plou, Pablo; Oro, Luis A. (2003). "Versatility of Cyclooctadiene Ligands in Iridium Chemistry and Catalysis". Organometallics. 22 (26): 5406–5417. doi:10.1021/om034218g.