Chlorobis(cyclooctene)iridium dimer explained

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.

The compound is prepared by heating an alcohol solution of sodium hexachloroiridate with cyclooctene in ethanol.^[1] The coe ligands are easily displaced by other more basic ligands, more so than the diene ligands in the related complex cyclooctadiene iridium chloride dimer. For example, with triphenylphosphine (PPh₃), it reacts to give IrCl(PPh₃)₃:^[2]

Ir₂Cl₂(C₈H₁₄)₄ + 6 PPh₃ → 2 IrCl(PPh₃)₃ + 4 C₈H₁₄

References

1. Book: 10.1002/9780470132456.ch18. Chlorobis(cyclooctene)rhodium(I) and -Iridium(I) Complexes. Inorganic Syntheses. 92–95. 1973. 14. van der Ent. A.. Onderdelinden. A. L.. 978-0-470-13174-9 .
2. Book: 10.1002/9780470132579.ch35. An Iridium(III) Complex Containing Cyclometallated Triphenylphosphine Formed by Isomerization of an Iridium(I) Triphenylphosphine Complex. 26. 200–203. 1989. Bennett. M. A.. Latten. J. L.. Inorganic Syntheses . 978-0-471-50485-6 .