Recognitory Coloration of Cations with Chromoacerands

A series of azophenol-dyed macrocycles, which accommodate selectively a given metal or ammonium ion in their cavity and undergo a concurrent color change, were designed and synthesized in order to study molecular recognition in biological systems. Selective coloration of some azophenol hosts and selective fluorescent emission of benzothiazolyl crowns for metal cations are observed to be useful for lithium analysis. Amine selective coloration with some azophenol hosts including enantiomeric discrimination are reported and X-ray crystal structures of sec.-amine inclusion complexes are illustrated. Selective coloration with two acerands is capable of discriminating the substitution pattern of alkylamines.