Dual-Signaling Fluorescent Chemosensors Based on Conformational Restriction and Induced Charge Transfer.

Twist and shout! By restricting conformation, 2,6-biarylpyridines can be induced to "speak" to us through increased fluorescence emission. In combination with induced charge transfer, this allows these simple fluorophores to reveal otherwise silent binding events to alkali metal and alkaline earth cations through brightening and color change (see picture; from left to right: no metal, Li+ , Mg2+ , and Ca2+ ).