High Resolved <sup>2</sup>H NMR Spectroscopy at Deuterium Natural Abundance Level
The spin-lattice relaxation times T 1 for deuterium nuclei in several deuterated compounds (methanol-d 4, ethanol-d 6, benzene-d 1, dimethylsulfoxide-d 6) were measured at higher temperatures (in the range 300-375 K). In all cases almost linear increase of times T 1 with temperature was observed revealing increase of molecular mobility and decrease of the correlation times. One may expect relaxation times of order 2-3 s for deuteriums in small organic molecules at temperatures above 350 K. Thus for the standard magnetic field inhomogeneity of order 0.5 Hz in NMR 1H one can obtain linewidths of order 0.1-0.2 Hz in 2H NMR spectra. Such “high resolved” 2H NMR spectra give the information about chemical shifts and coupling constants J(H-D) (or J(H-H)= ( H/ D) J(H-D)) including those between magnetically equivalent protons unobservable in 1H NMR spectra. New or more exact data on coupling constants were obtained for ethanol, propanol, 1,2-dichloroethane and 1,4-dioxane.