A COMPARATIVE THEORETICAL INVESTIGATION OF MAGNESIUM INSERTION INTO THE C-X BOND IN VINYL HALIDES (X = F, Cl, AND Br)

In the present study, the insertion of the magnesium atom into the carbon halogen bond of vinyl halides (X = F, Cl, and Br) is studied via B3LYP density functional calculations with a 6-311G(d,p) basis set. A 3-centered transition state with a single imaginary frequency is obtained for all three reactions. The potential energy profile is determined in both directions for all the systems along the intrinsic reaction coordinate. All the transition states obtained lie on the potential energy surface. The three Grignard reactions are exothermic in nature, as indicated by the energetics of the reactions. Electron correlation inclusion has increased the exothermicity of the reactions. Atom in molecules (AIM) analysis predicted the ionic character of the Mg-C and X-Mg bond in the product, C2H3MgX, where X = F, Cl, and Br, as compared to all the other bonds. Results obtained in our study at the DFT level are in agreement with the previous MP2 and HF calculations.