C-13 NMR RELAXATION STUDIES OF 1/2 LICL-ETHYLALUMINUM DICHLORIDE SOLUTIONS

A new room-temperature molten salt, 1:2 LiCl-ethylaluminum dichloride (LiCl-EtAlCl(2), f.p. about 178 K), is examined using C-13 relaxation methods at 7.05 T (-25 to +80 degrees C). The methylene carbon undergoes scalar relaxation of the 'second kind' as it is coupled to a faster relaxing (quadrupolar) nucleus. LiCl-EtAlCl(2), undergoes a significant liquid-state phase change between 5 and 15 degrees C as evidenced by observed changes in the relaxation properties of the methylene and methyl carbons and J(C-13-Al-27). The J(C-13-Al-27) coupling constants are 75 (-10 to +5 degrees C) and 11 Hz (15-65 degrees C), indicating a change in structure between 5 and 15 degrees C. Chemical shift anisotropies of 56 and 48 ppm are obtained for the methylene and methyl carbons in the EtAlCl(2), dimer part of the 1:2 LiCl-EtAlCl(2) solution.