| Abstract
| - Becke3LYP calculations lead to a detailed mechanistic proposal for alkane activation by metallocarbene complexes that reproduces and explains the observed experimental dependence of the activation barrier on the nature of the alkane and the metal complex.
- DFT Becke3LYP calculations are applied to the computational study of the activation of alkane C−Hbonds by metallocarbene homoscorpionate complexes. A total of 16 different combinations ofmetallocarbene complex and alkane are explored, defined by the use of TpAgC(H)(CO2CH3), TpBr3AgC(H)(CO2CH3), TpCuC(H)(CO2CH3), and TpBr3CuC(H)(CO2CH3) species as metallocarbene andmethane, ethane, propane, and butane as alkane. The reaction is found to be under kinetic control, andthe selectivity is decided in a step with a low-barrier transition state where the key bond-breaking andbond-forming processes take place in a concerted way. This transition state has several possibleconformations, which are systematically explored to find the one with lowest energy for each reaction.Variations of the energy barrier as a function of the nature of metal, ligand, and alkane are analyzed anddiscussed.
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