Anion binding dipolar electrostatic interaction

Dipolar electrostatic interactions have also been manipulated for the purposes of anion binding. Macrocyclic receptor 10 was shown to be capable of binding halide anions through interactions with the positive ends of the S = O and P = O dipoles (54). Evidence was also provided for the simultaneous binding of primary alkyl ammonium cations (to the oxygen atoms) and halide anions (to the dipoles). This topic of simultaneous cation and anion recognition is of considerable current interest. Further examples will be encountered during this chapter. 

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