Anion Recognition and Binding Constant Determination

This chapter describes anion recognition and experimental approaches to determine the equilibrium constants associated with complexation events of importance to anion-assisted catalysis. Examples are drawn from the fields of anion-derived recognition and catalysis. The concepts of complementarity, preorganization, cooperativity, and others are highlighted to guide best practices in receptor design. 1 H-NMR and UV–visible spectroscopy are highlighted as exceptional experimental tools. Experimental planning outlines the identification of all key host–guest complexes to generate a binding model that describes the dominant set of equilibrium reactions in a solution. The strategies and best practices are outlined for the accurate quantification of equilibrium constants. Circumstances and strategies are outlined to address complications arising from competitive ion pairing and formation of higher order complexes. These tools and concepts are all essential for establishing accurate binding constants to enrich investigations into catalytic systems that involve anion binding equilibria.