C-13 AND AL-27 NMR RELAXATION STUDIES OF ETHYLALUMINUM DICHLORIDE

A new component of room-temperature molten salts, the dimer of ethylaluminum dichloride, EtAlCl(2), is examined with C-13 and Al-27 relaxation methods at 7.05 and 11.75 T (35-70 degrees C). The methylene carbon undergoes scalar relaxation of the ''second kind'' as it is coupled to a faster relaxing (quadrupolar) nucleus. Dimeric EtAlCl(2) undergoes a significant ''self-perturbation'' or liquid-state phase change between 50 and 60 degrees C, as evidenced by observed changes in its relaxation properties and J(AlC). The J(AlC) coupling constants are 191 (30-50 degrees C) and 165 (55-70 degrees C) Hz. A liquid-state quadrupolar coupling constant (chi) of 71.9 MHz is determined for the EtAlCl(2) dimer using the dual spin probe method, assuming that the asymmetry parameter of the electric field gradient (eta) is zero. (C) 1994 Academic Press, Inc.