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Characteristic structural-dynamic features of crystalline CCl/sub 3/CCl/sub 2/N=CClCCl/sub 3/ from /sup 35/Cl NMR data

Journal Article · · J. Struct. Chem. (Engl. Transl.); (United States)
OSTI ID:6595905

In the present work, the temperature dependence of the resonance frequencies v and the spin-lattice relaxation times of the /sup 35/Cl nuclei T/sub 1/ were recorded for the compound CCl/sub 3/CCl/sub 2/N=CClCCl/sub 3/ which was synthesized and purified by a previously published method. The measurements were made in the range from 77/sup 0/K to the melting point (345/sup 0/K), and the procedure for obtaining and treating the experimental data was analogous to that described earlier. The spectral and relaxation data show that the behavior, with change in temperature, of the three /sup 35/Cl NQR lines assigned to one of the CCl/sub 3/ groups in the molecule differs considerably from that of the lines of the other trichloromethyl group. The former correspond to a larger temperature coefficient of the NQR frequency (..delta..v/..delta..T) and also to a shorter time T/sub 1/ in the region of 77/sup 0/K, which decreases exponentially with increase in temperature, leading to fading of the resonance signals at 235/sup 0/K (see Fig. 1), that is approx.100 degrees below the melting point of the specimen. This indicates that the corresponding CCl/sub 3/ group I has a higher liberational and reorientational mobility, and makes it possible to assign it to the fragment CCl/sub 3/CCl=N. Quantitative analysis of the temperature dependence of the spin-lattice relaxation time of the /sup 35/Cl nuclei made it possible to determine the magnitude of the potential barriers V..xi.. of the recorded intracrystalline motions.

OSTI ID:
6595905
Journal Information:
J. Struct. Chem. (Engl. Transl.); (United States), Journal Name: J. Struct. Chem. (Engl. Transl.); (United States) Vol. 22:6; ISSN JSTCA
Country of Publication:
United States
Language:
English