PROTON NMR INVESTIGATION OF MOLECULAR-DYNAMICS IN [N(CH3)4]3 SB2BR9 (TEMABA)

Cation dynamics in tris (tetra-methylammonium) nonabromodiantimonate, which shows structural phase transitions, are studied through proton s pin lattice relaxation measurements (at two Larmor frequencies) and li ne width measurements. Results show a clear signature of a phase trans ition at 189 K and the existence of dynamically inequivalent methyl gr oups. The dynamics of the cation as a whole are found to be less hinde red above this temperature. Activation energies associated with the dy namics of the cations and methyl groups are calculated.