Carboxylic acid derivatives of tetrathiafulvalene: key intermediates for the synthesis of redox-active calixarene-based anion receptors

A series of calixarene-TTF (TTF=tetrathiafulvalene) receptors incorporating amide binding units for anion recognition have been synthesized and characterized. For this purpose, two synthetically versatile new TTF carboxylic acid derivatives were prepared and characterized by X-ray diffraction, these structures demonstrating the critical role of the carboxylic function in the solid-state organization. Some of the calixarene-amide-TTF assemblies exhibit strong binding of various anions, as shown by H-1 NMR titration studies, and one receptor is able to electrochemically respond in the presence of H2PO4-. C6H5CO2- or CH3CO2- anion. (C) 2007 Elsevier Ltd. All rights reserved.