Synthesis and anion-binding properties of new disulfonamide-based receptors

The synthesis of disulfonamide receptor scaffolds for anion binding is reported. Acyclic receptors are found to tightly bind acetate in MeCN-d3 with dominant 1:1 stoichiometry, a smaller, sequential 1:2 (H+G) association is also found. Constraint of the disulfonamide receptor into macrocycles serves to eliminate the 1:2 binding stoichiometry and X-ray crystal structures of several macrocyclic receptors allow rationalisation of their affinity for acetate binding. l-Valine derived macrocycles maintain tight 1:1 binding of acetate (Ka1:1 >104 M−1) in MeCN-d3 and display preference for oxyanion binding in more competitive MeCN-d3/2% H2O.