Colorimetric Sensors Based on Hydrogen-bond-induced π-delocalization and/or Anion-triggered Deprotonation

Most receptors are designed to explore the anion-binding affinities for medical, biological, environmental relevant anions. Of the major types of receptors, sensors related to hydrogen bond have been studied widely by numerous researchers. Both hydrogen-bond-induced π-delocalization and anion-triggered deprotonation govern the signal transduction of the binding events in these systems. An overview of the inclusion of the (thio)urea and pyrrole groups within synthetic receptor molecules is presented in this article.