What Molecules Are Likely or Unlikely To Undergo Pedal Motions in Crystals?
| Autor: | Jun Harada, Keiichiro Ogawa |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Crystal Growth & Design. 14:5182-5188 |
| ISSN: | 1528-7505 1528-7483 |
| DOI: | 10.1021/cg500962y |
| Popis: | The crystal structures of several (E)-stilbenes and 1,2-diarylethane that have methyl or chloro substituents were examined by variable-temperature X-ray diffraction analysis. All the compounds showed disorders in their crystal structures at least at room temperature. In the crystal structures of the molecules with ortho-methyl groups, the disorder observed at room temperature disappeared at 90 K. The dynamic disorders in these crystals were explained in terms of the conformational changes induced by pedal motions, which were not obstructed by the ortho-methyl groups. In the crystals of the stilbenes with α-substituents, however, the populations of the two disordered conformers did not change with temperature, which indicates that the disorders were static and these molecules did not undergo the pedal motions in their crystals. Theoretical calculations on the energy barriers for the pedal motions indicated that the observed restriction of the pedal motion in crystals was originated not only in the intramol... |
| Databáze: | OpenAIRE |
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