Carbon-13 nuclear magnetic resonance spectrometric investigation of acetonitrile-tetraalkylammonium salt interactions

Abstract

Carbon-13 nuclear magnetic resonance spectroscopy has been used to observe changes In the carbon spin-lattice relaxation time (7^) of acetonitrile as a function of salt concentration In the range from 0.01 to 1.4 M. The Tt of the nitrito carbon was observed to be sensitive to salt concentration with a minimum at about 1 M. The trend In TJs parallels a trend In relative Intensities of the NMR signals of the methyl and nitrito carbons with salt concentration, thus showing concentration-dependent Interactions between the solute and solvent molecules. Models for the salt-acetonltrlle interactions consistent with the observed behavior are proposed.