Cyclooctadiene iridium chloride dimer is an

organoiridium compound 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 synthesi ...

with the formula r(μ²-Cl)(COD)sub>2, where COD is the diene

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 ...

(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.

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). 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. The complex is widely used precursor to other iridium complexes. A notable derivative is Crabtree's catalyst. The chloride ligands can also be replaced with methoxide to give cyclooctadiene iridium methoxide dimer, Ir₂(OCH₃)₂(C₈H₁₂)₂. The cyclooctadiene ligand is prone to isomerize in cationic complexes of the type (C₈H₈)IrL₂]⁺.

References

{{Iridium compounds Homogeneous catalysis Coordination complexes Cyclooctadiene complexes Organoiridium compounds Chlorides

Preparation, structure, reactions

See also

References