Allosteric Binding of Capsaicin by a Bis(β-cyclodextrin)-2,2′-bipyridine Receptor

A new β‐cyclodextrin‐based receptor that showed allosteric binding behavior towards capsaicin in aqueous solution was prepared. By NMR titration and nonlinear regression, we obtained binding constants, which increased more than fivefold when an effector (Zn2+) was bound to a central 2,2′‐bipyridine that acts as the allosteric center. Allosteric recognition: A new β‐cyclodextrin‐based receptor was developed. This receptor showed positive allosteric binding behavior towards capsaicin in aqueous solution that can be regulated by a zinc(II)–phenanthroline complex as an effector (see scheme).