Synthesis and characterisation of polyaza crown ether derivatives of calix[4]arene and their role as anion receptors

Novel compounds of polyaza crown ether derivatives of calix[4]arene have been synthesised. Both the ammoniun and methyl ammonium derivatives, 25,27-{2,2'-[2,2'-((2,5,8-triammonium)nonyl)diphenoxyl]diethyl}-p-tert-butylcalix[4]arene trichloride, Ib and 25,27-(2,2'-[2,2'-((2,5,8-dimethyl ammonium)nonyl)diphenoxy]diethyl}-p-tert-butylcalix[4] arene, Id, were studied complexation with a series of anions by H-1 NMR spectroscopy. The ammonium derivatives, Ib, was found to form complexes Cl-, with Cl-, NO3-, AsO2- and CO32- ions in which the selectivity for anions varies as CO32- > NO3- > AsO2- > Cl-. The methylammoniun derivative, Id, however, does not show any sign of anion complexation. (C) 1997 Elsevier Science Ltd.