Polymer-Bound Molecular Tweezers

Significance

A pH-sensitive ‘molecular tweezer’ embedded within a polymer backbone is reported. Polymer 1 contains multiple pendant groups each comprised of a 2,6-bis(2-methoxyphenyl)-pyridine switching unit tethered to two naphthalene groups. Together, the terminal aromatic surfaces act as a molecular binding pocket for specific substrates. On addition of acid, the pyridinium species formed is predisposed to form hydrogen bonds with the sterically accessible phenoxy groups, and the stacked naphthalene arrangement is disrupted resulting in substrate release (2).