Specific solvent effect on R2ZrCl2 (R=butyl, ethyl) reactivity, a density functional study

The reactivity of ZrCl2Bu2 is modeled for the formation of ZrCl2(butene). Two pathways are computed: the β- and the γ-Hydrogen migration. It is found that the β-H pathway is favored by about 13 kcal mol−1. The specific effect of dimethyl ether as a model of the THF solvent is analyzed and found to greatly facilitate the reaction. Solvent or ligand complexation on the zirconium is found more important in product ZrCl2(butene) than in the reagent ZrCl2Bu2. These results are commented in regard to the experimental evidences of reactivity differences depending on the solvent used.