Proton NMR ion binding studies of ethanol and the ethylammonium ion partially oriented in an amphiphilic nematic liquid crystal

Abstract

The proton NMR spectra of ethanol and the ethylammonium ion have been investigated in an amphiphilic nematic liquid crystal mixed detergent system KDDG/TDTMABr. The binding of ethanol was found to be as equally strong with the cationic as with the anionic detergent. The ion binding for the ethylammonium ion was found to be the weakest with the cationic detergent. A multi-site ion binding model is suggested for the ethylammonium ion where the sites originate from orientational order rather than multicoordination. pH measurements eliminated the multi-species model and the continuous site model is eliminated because the three dipolar couplings of the ethyl ammonium ion do not move through zero simultaneously.