Colorimetric and fluorescence sensing of anions using thiourea based coumarin receptors

Thiourea-containing coumarins 1, 2 have been designed and synthesized via reaction of 6-aminomethylcoumarin and the corresponding isothiocyanates. Their anion-binding ability has been examined using UV-vis, fluorescence and H-1 NMR. The anion recognition takes place through charge neutral thiourea receptor sites with concomitant fluorescence quenching of the coumarin moiety with 1 showing a strong binding to C6H5COO- over F- with a distinct change in color. (c) 2006 Elsevier Ltd. All rights reserved.