10.1021/jp5009994.s001 Andrea Cerda-Monje Andrea Cerda-Monje Rodrigo Ormazábal-Toledo Rodrigo Ormazábal-Toledo Carlos Cárdenas Carlos Cárdenas Patricio Fuentealba Patricio Fuentealba Renato Contreras Renato Contreras Regional Electrophilic and Nucleophilic Fukui Functions Efficiently Highlight the Lewis Acidic/Basic Regions in Ionic Liquids American Chemical Society 2014 Ionic LiquidsThe origin reference ion pair structure Lewis acidity hydrogen bond Regional Electrophilic Nucleophilic Fukui Functions Efficiently Highlight polarization effects cation effect Fukui function anion effect bifunctional distribution room temperature hydrogen bond donor ability basicity functions 2014-04-03 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Regional_Electrophilic_and_Nucleophilic_Fukui_Functions_Efficiently_Highlight_the_Lewis_Acidic_Basic_Regions_in_Ionic_Liquids/2309677 The origin of catalysis and selectivity induced by room temperature ionic liquids in several organic reactions has putatively been associated with the concept of <i>cation effect</i> (hydrogen bond donor ability of the ionic liquids) or <i>anion effect</i> (hydrogen bond accepting ability of the ionic liquids). We show that there may be cases where this a priori classification may not be correctly assigned. Cations may concentrate both Lewis acidity and basicity functions in one fragment of the ionic liquid: an effect we tentatively call bifunctional distribution of the molecular Lewis acidity/basicity. Bifunctionality on the cation is however anion dependent through electronic polarization effects. The molecular distribution of the Lewis acidity/basicity may simply be assessed by evaluating the regional Fukui function within a reference ion pair structure. The model is tested for a set of nine ionic liquids based on the 1-butyl-3-methylimidazolium cation commonly used as solvent to run organic reactions.