DFT and ab initio study on mechanism of olefin hydroalumination by XAlBui2 in the presence of Cp2ZrCl2 catalyst. III. Efficiency of transmetallation in Cp2ZrRCl–XAlBui2 system

Transmetallation leading to formation of n-Pr–Al bond in the Cp2Zr(n-Pr)Cl–XAlBui2 (X = H, Cl, Bui) couple was studied using PBEPBE/3ζ and RI-MP2/Λ2//PBEPBE/3ζ approaches. Calculation results were corrected by taking into account of nonspecific solvent effect (toluene). Depending on the nature of organoaluminum compound, either decomposition of alkylalane self-associates (HAlBui2 and ClAlBui2 cases) or alkyl group transfer reaction from Zr to Al atom (AlBui3 case) could be a rate-determining step of the process. The modeling of kinetics with calculated Gibbs free energies for elementary steps of the process shows that transmetallation rates decrease in the following order: ClAlBui2 > HAlBui2 >> AlBui3.