Chiral Crystals of an Achiral Molecule Exhibit Plastic Bending and a Crystal-to-Crystal Phase Transition
| Autor: | Mohamed Ghazzali, Dmitriy V. Soldatov, Melissa Ignacio, Adam C. Maahs, Kathryn E. Preuss |
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| Rok vydání: | 2017 |
| Předmět: |
Phase transition
Materials science 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Crystal Crystallography Differential scanning calorimetry Plastic bending General Materials Science Sublimation (phase transition) Plastic crystal 0210 nano-technology Single crystal Monoclinic crystal system |
| Zdroj: | Crystal Growth & Design. 17:1390-1395 |
| ISSN: | 1528-7505 1528-7483 |
| DOI: | 10.1021/acs.cgd.6b01819 |
| Popis: | The achiral molecule 2-cyano-4,6-dimethylpyrimidine (Me2pmCN) meets simple criteria that predict a supramolecular arrangement capable of exhibiting plastic bending. Indeed, crystals grown by sublimation bend readily without breaking under manual manipulation at room temperature. Compression of a crystal perpendicular to the bending direction easily “squashes” the crystal, a mechanical response akin to metal-like malleability. Single crystal X-ray diffraction (XRD) study reveals net alignment of the molecular dipoles propagating along the 21 screw axis in the monoclinic space group P21. Columnar π-stacked arrays of the planar molecules extend in [100], the long axis of the crystals. Weak interactions between the columnar structures account for the observed mechanical behavior. Variable temperature powder XRD and differential scanning calorimetry measurements of the plastic crystals indicate a solid-to-solid phase transition from one crystalline phase to another at 80.7 °C prior to melting at 83.3 °C. |
| Databáze: | OpenAIRE |
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