Elimination of HBr from CH3Br by Cu+ and Au+: A DFT study

The elimination of HBr from CH3Br by ground state of Cu+ and Au+ has been investigated by using DFT methods. A mechanism of one-step HBr elimination leading to CuCH2+ was identified. For the formation of AuCH2+, besides the one-step mechanism, another two-step HBr elimination pathway through a C–Br bond insertion intermediate was also found, and this pathway is energetically more favorable than the one-step mechanism. The calculated reaction energy barriers show that the formation of AuCH2+ is energetically much more favorable than the formation of CuCH2+. The experimental observations are well explained.