Ionic liquids through the looking glass: theory mirrors experiment and provides further insight into aromatic substitution processes.

Aromatic substitution of 1-fluoro-2,4-dinitrobenzene has been shown to proceed more rapidly in an ionic liquid than in ethanol, primarily due to entropic, rather than enthalpic, effects. By using molecular dynamics simulations, an anion-pi interaction appears to contribute to strong ordering within the starting material complex that accounts for the relative differences in the S(N)Ar k.