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Reversible piezochromism in a molecular wine-rack
Elena L Harty1, Alex R Ha, Mark R Warren
1Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, UK. nicholas.funnell@chem.ox.ac.uk.
Chemical Communications (Cambridge, England)
|May 28, 2015
Summary
The ROY system shows a reversible color change from yellow to red when pressure is applied. This color change is due to a unique molecular mechanism within the yellow crystal form.
Area of Science:
- Solid-state chemistry
- Materials science
- Crystallography
Background:
- The ROY system is known for its polymorphism and strong coloration.
- Piezochromism, a change in color due to pressure, is a fascinating phenomenon in materials science.
Purpose of the Study:
- To investigate the piezochromic response of the ROY system under hydrostatic compression.
- To elucidate the structural mechanism behind the pressure-induced color changes in the yellow polymorph.
Main Methods:
- Hydrostatic compression experiments were performed on the ROY system.
- Structural analysis of the yellow polymorph under pressure was conducted.
- Reversibility of the piezochromic behavior was examined upon decompression.
Main Results:
- The ROY system exhibited a distinct yellow → orange → red piezochromic response.
- The yellow (Y) polymorph utilizes a wine-rack-type mechanism for pressure accommodation.
- This mechanism is facilitated by molecular conformational flexibility while preserving crystal symmetry.
- The observed behavior was reversible upon decompression from 1.49 GPa.
Conclusions:
- The ROY system demonstrates a reversible piezochromic response driven by a specific structural mechanism in the yellow polymorph.
- Molecular flexibility plays a crucial role in accommodating pressure and enabling the color transition.
- This study provides insights into the design of pressure-responsive materials.
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