Selective host-guest binding of anions without auxiliary hydrogen bonds: Entropy as an aid to design

Entropy matters! In contrast to classic host-guest design, which employs dedicated enthalpic interactions of the binding partners, the novel electroneutral host 1 binds its anionic guests by virtue of an overwhelmingly positive entropy of association. The prime driving force is guest desolvation. Despite the total omission of hydrogen bonding, host 1 is one of the best electroneutral receptors known for binding anions in polar solution.