Crossed-beam measurements of the reaction of FOH- with CH3I forming FIOH- shows suppression of low product kinetic energies.
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A similar suppression is found in the ligand switching reactions of Cl-(H2O) with CH3I forming Cl-(CH3I).
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This observation is explained by a competition of the above reactions with different product channels.
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This also sheds new light on the nucleophilic substitution reaction of Cl-(H2O) with CH3I.
Abstract
Substantially different reaction dynamics, product branching ratios and time scales have been reported in crossed beam imaging experiments on the nucleophilic substitution reactions of Cl−(H2O) and F−(H2O) with CH3I at 0.3 eV collision energy [Bastian et al., J. Phys. Chem. A 124, 1929 (2020)]. In particular, it was speculated that Cl−(H2O) only undergoes nucleophilic substitution via a ligand exchange intermediate. Here, we present crossed-beam scattering results for the two title reactions that both show a suppression of low product kinetic energies. We discuss this mechanism in comparison with recent results on the ligand exchange in F−(H2O) + CH3I collisions. This also allows for a more detailed picture of the dynamics of hydrated nucleophilic substitution reactions at low collision energy.
