The influence of fluorination on the dynamics of the F + CHCHI reaction.

The competition between the bimolecular nucleophilic substitution (S2) and base-induced elimination (E2) reaction and their intrinsic reactivity is of key interest in organic chemistry. To investigate the effect of suppressing the E2 pathway on S2 reactivity, we compared the reactions F + CHCHI and F + CFCHI. Differential cross-sections have been measured in a crossed-beam setup combined with velocity map imaging, giving insight into the underlying mechanisms of the individual pathways. Additionally, we employed a selected-ion flow tube to obtain reaction rates and high-level computations to characterize the different reaction pathways and product channels. The fluorination of the β-carbon not only suppresses the E2-reaction but opens up additional channels involving the abstraction of fluorine. The overall S2 reactivity is reduced compared to the non-fluorinated iodoethane. This reduction is presumably due to the competition with the highly reactive channels forming FHF and CFCI.