A novel chromo- and fluorogenic dual responding H2PO4- receptor based on an azo derivative

A simple, novel anion receptor based on 4-hydroxy-3-(N-phenyl-thiourea-N'-nitrilo-methylidynyl)-azobenzene with hybrid -OH and thiourea binding sites was synthesized and characterized. Anion binding character was determined using visual inspection, UV-vis, fluorescence and H-1 NMR analyses. The addition of F-, AcO- and H2PO4- resulted in a marked red shift of the charge-transfer absorbance band (Delta lambda = 140 nm, from 340 nm to 480 nm) accompanied by a color change from light yellow to orange. (C) 2008 Elsevier Ltd. All rights reserved.