| Autor: |
Sidhu, P. S., Enright, G. D., Ripmeester, J. A., Penner, G. H. |
| Zdroj: |
The Journal of Physical Chemistry - Part B; August 2002, Vol. 106 Issue: 34 p8569-8581, 13p |
| Abstrakt: |
Various physicochemical characterization techniques were used to study the structure and guest dynamics of the 1,2-dichloroethane/tris (5-acetyl-3-thienyl) methane (TATM) inclusion compound. This complex was observed to crystallize in two forms, a triclinic P-1 structure and a less usual monoclinic P21/c form. The X-ray structures indicate that the TATM molecules form bottleneck channels parallel to the crystallographic c axis in both forms and that the guests exist exclusively in the trans form. Solid-state deuterium NMR spectroscopy was used to study the dynamics of the 1,2-dichloroethane-d4 guest in the triclinic form. The simplest model consistent with the experimental NMR spectra was based on internal rotation about the C−C bond (a trans/gauche conformational equilibrium). As this was not consistent with the X-ray structure, another model was developed where the trans conformer performs 180° flips about an axis through the center of symmetry of the guest and perpendicular to the Cl−C−C−Cl plane. The important point to be taken from this work is that complementary methods are often necessary to discriminate between motional models based on a single technique, and that the simplest model is not necessarily correct. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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