Exploring the H-abstraction reactions of CHCl·−/CCl2·− with CX3H (X = F, Cl, Br and I) using the density functional theory method

Gas-phase hydrogen abstraction reactions have been compared using the popular density functional theory (DFT) functional BHandHLYP/aug-cc-pVTZ/RECP level of theory, on the basis of the model reaction CHCl·−/CCl2·− + CX3H (X = F, Cl, Br and I). Our theoretical findings suggest the efficiency of the H-abstraction reactions induced by either CHCl·− or CCl2·− increases as the substrate is changed from CF3H to CI3H, and that CHCl·− has a higher activity in hydrogen abstraction than CCl2·− for a given substrate. The entropy effect at 298 K does not significantly change the trend in reactivity of the various reactions, which is in general controlled by the heights of activation energies ΔE≠. Therefore, we have explored the origin of the energy barriers ΔE≠ of the reactions using the activation strain model of chemical reactivity.