Enthalpy changes in oxidative addition reactions of organic iodides with trans-chlorocarbonylbis(trimethylphosphine)iridium(I)

Article abstract of DOI:10.1021/ic50215a016

Titration calorimetric methods have been used to determine enthalpies of the oxidative addition reaction of trans-[IrCl-(CO)(PMe₃)₂] with I₂, HI, CH₃I, C₂H₂I, n-C₃H₇I, i-C₃H₇I, C₆H₅CH₂I, CH₃C(O)I, and C₆H₅C(O)I in 1,2-dichloroethane. Heats of solution of selected metal complexes and iodo compounds have been determined. These results were used to calculate ΔH° values for the oxidative addition reactions. Combination of the ΔH° values and heats of formation of the appropriate compounds has made it possible to calculate ΔH° for the β-elimination reaction of an ethyl complex, CO insertion into the Ir-CH₃ bond, and the isomerization of an isopropyl to an n-propyl complex. A relative scale of bond energies, D(Ir-R) - D₁(Ir-I) has been determined based on the data obtained in this study. The general trend in D(Ir-R) is H > CH₃ ≈ I ≈ CH₃C(O) > C₂H₅ > n-C₃H₇ > i-C₃H₇ > CH₂C₆H₅.