Elimination of HF from CH3F by As+ and Bi+: A comparative theoretical study

The reactions of ground state As+ and Bi+ with CH3F have been investigated at B3LYP and CCSD(T) levels of theory. Two pathways were found for the HF-elimination reactions for both the two atomic ions. The reaction 3As+ + CH3F→3AsCH2+ + HF is exothermic by 72.4 kJ/mol, whereas the reaction 3Bi++CH3F→3BiCH2+ + HF is endothermic by 45.7 kJ/mol. The lowest energy pathway for the reaction of As+ with CH3F has activation energy of 70.7 kJ/mol while the corresponding barrier for the reaction of Bi+ with CH3F is much higher (174.6 kJ/mol). The higher reactivity of As+ toward CH3F rationalizes the experimental results of the efficient formation of AsCH2+ and the absence of BiCH2+.