NEW DITOPIC RECEPTORS FOR ALKYLAMMONIUM ION COMPLEXATION

New receptor molecules have been synthesized in which lpha'-bis-(4-hyd roxyphenyl)-1,4-diisopropylbenzene is linked to 1,10-diaza-18-crown-6, 1,10-diaza-21-crown-7 or 1,13-diaza-24-crown-8 units by ethylene or 1 ,4-butylene bridges. Binding abilities of the new receptors and the mo del compound N,N-didecyl-1,10-diaza-18-crown-6 toward alkali metal cat ions and alkylammonium ions were assessed by picrate extraction. Spect ral evidence for inclusion of alkylammonium ions within the receptor c avity was obtained by H-1 NMR spectroscopy. From a H-1 NMR titration e xperiment conducted in CDCl3-CD3OD (9:1), a relatively strong inclusio n complex (K(a) approximately 900 M-1) of the receptor having a 1,10-d iaza-18-crown-6 subunit and ethylene spacers with propylammonium picra te was observed.