Trihalomethyl Cations and Their Superelectrophilic Activation1

Ab initio molecular orbital and density functional theory (DFT) calculations were performed to investigate energies, geometries, and reactivities of halomethyl cations and their protonated analogues. On the basis of calculated energies the observed superelectrophilic activation of the halomethyl cations in superacid solutions is discussed. The protonated halomethyl cations have considerable kinetic and thermodynamic stability. 13 C NMR chemical shifts of selected systems were calculated by IGLO method and compared with experimental data.