Nuclear magnetic resonance spin–lattice relaxation and barriers in ethylenediammonium chloride, bromide, iodide and sulphate

Abstract

N.m.r. T1 has been studied as a function of temperature in the Cl–, Br–, I– and SO42– salts of the ethylenediammonium ion +NH3CH2CH2NH3+. The chloride and sulphate show phase transitions at elevated temperatures. The T1 minima of 21–22 ms (at 31 MHz) in all four salts may be interpreted in terms of —NH3+ reorientation. The observed activation energies for this motion, which vary between 41.3 and 8.6 kJ mol–1, have been related where possible to the nature of the group's environment.