Theoretical study of lanthanide mono cation-mediated C-F bond activation

The potential energy surface corresponding to the reaction of lanthanide mono-cations (Ln(+); Ln = Ce-Yb) with CH3F has been investigated using density functional theory calculations. In the initial step of the C-F activation reaction, Ln(+) directly coordinates to the F atom of CH3F, and forms same [Ln center dot center dot center dot F center dot center dot center dot CH3](+) type transition state structures with an accompanying electron-transfer from the Ln(+) to the F atom. Performing intrinsic reaction coordinate calculations from the transition states, we found that all Ln(+) reactions can be classified into one of two different reaction mechanisms, "harpoon-like'' and "insertion-elimination'', which were experimentally proposed by Cohrnel et al. and Konayagi et al., respectively. The two mechanisms have been proposed exclusive to each other. Our results show that both reaction mechanisms are possible in Ln(+) reaction systems. (C) 2010 Elsevier B.V. All rights reserved.