Synthesis and characterization of a novel chiral chromogenic calix[41(azoxa)crown-7

Two new chromogenic compounds, 5 and 6, and a novel chiral chromogenic calix[4](azoxa)crown-7 8 have been synthesized using a calix[4]arene platform. The starting reagents chiral diamine e and calix[4]arene diacid chloride derivative 7 were prepared conveniently according to recent approaches. The H-1 and C-13 NMR, data showed that these compounds exist in a cone conformation. Compounds 5 and 8 have shown broad absorption bands in UV-vis spectra suggesting their utility in different fields, for example, as sensors for ions as well as for chiral molecules. (C) 2004 Elsevier Ltd. All rights reserved.