H. Niki et al., INEQUIVALENT REORIENTATION OF THE TRICHLOROMETHYL GROUPS IN 1,4-BIS(TRICHLOROMETHYL) BENZENE AS STUDIED BY PULSED CL-35 NQR, Zeitschrift fur Naturforschung. A, A journal of physical sciences, 49(1-2), 1994, pp. 273-278
The temperature dependence of T1 of Cl-35 NQR of the title compound ev
idenced that the three crystallographically inequivalent CCl3 groups h
ave different potential barriers against reorientation (about 30, 36,
and 42 kJ/mol). An intramolecular interaction between pi-electrons on
the benzene ring and the C-Cl bond is proposed to interpret the charac
teristic frequency splitting common to the Cl-35 NQR spectrum of each
of the three inequivalent CCl3 groups. The magnitude of T2 of each Cl
atom is interpreted by intra- and intermolecular H...Cl interactions.
It was found that only part of the temperature dependence of the NQR f
requency can be interpreted by reorientation.