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  F- + C2H5I SN2 and E2 Reaction Dynamics

This study is part of a research collaboration with the Roland Wester Research Group, University of Innsbruck, Austria, and Li Yang and Jiaxu Zhang Research Group, Harbin University, China. Direct dynamics simulations for the F- + CH3CH2I were performed with the M06/ECP/d electronic structure theory. The collision energy is 1.9 eV. Anit-E2, syn-E2 and inv-SN2 mechanisms were observed. A direct mechanism dominates all the reaction pathways at this high collision energy. Base-induced elimination is by far the dominant channel, with over 80% of the trajectories. A high fraction of the anti-E2 trajectories proceed via a direct pathway.

For the anti-E2 and syn-E2 mechanisms, the deprotonation of the β-hydrogen at the anti and syn positions with respect to the C-I bond, and the proton transfer, C-C double bond formation, and departure of the leaving group occur simultaneously. The inv-SN2 mechanism occurs via direct rebound and stripping mechanisms. For the rebound mechanism, F- attacks the backside of the α-C of CH3CH2I and directly displaces I-. Stripping occurs when F- approaches the α-C of CH3CH2I on its side and directly strips away the CH3CH2 group. Reports of this research are given in Nature Communications 8, 25 (2017), and Journal of Physical Chemistry A 121, 1078 (2017).

Trajectories Animated