The Scope and Chemical Relevance of Anion- Interactions Involving Aromatics: Computational and Solid-State Studies. Michael Lewis, Department of Chemistry, Saint Louis University Saint Louis, Missouri, 63103 Computational Modeling Studies. Work on anion binding of the transition metal complex Ar-FeII-Cp (Ar = substituted aromatic; Cp = cyclopentadienyl anion), shown on the right, shows the preference for anion binding of the -face of the aromatic with respect to the anion binding of the FeII center increases with negative p, electron donating substituents. Furthermore, there is a correlation between the anion- binding and the p value and this will allow us to predict when the anion- binding will be greater than the anion-metal binding depending on the aromatic substitution pattern. Synthetic Approach to Host for Solid-State Anion- Binding Studies. All but the last two steps in the synthesis of the desired anion-binding host have been completed, as shown in the figure on the right.