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Published on: December 27, 2018
Thermochromic discotic 6-oxoverdazyls.
Aleksandra Jankowiak1, Damian Pociecha, Hirosato Monobe
1Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.
Chemical Communications (Cambridge, England)
|June 12, 2012
Summary
Novel 6-oxoverdazyl radicals with trialkoxyphenyl groups form a columnar hexagonal phase. These stable organic radicals exhibit a reversible red-to-green color change upon heating, indicating potential in thermochromic materials.
Area of Science:
- Organic chemistry
- Materials science
- Physical chemistry
Background:
- 6-Oxoverdazyls are a class of organic radicals with interesting magnetic and optical properties.
- Tailoring substituent groups can influence the self-assembly and phase behavior of radical compounds.
Purpose of the Study:
- To synthesize and characterize novel 6-oxoverdazyl radicals with specific trialkoxyphenyl substituents.
- To investigate the mesophase behavior and thermochromic properties of these radical compounds.
Main Methods:
- Synthesis of 6-oxoverdazyl compounds 1b[n] with n=8 and 10.
- X-ray diffraction (XRD) for structural analysis.
- Magnetization measurements.
- Optical microscopy for phase transition observation.
Main Results:
- The synthesized 6-oxoverdazyls (1b[n]) exhibit a columnar hexagonal phase (Col(h)) below 130 °C.
- A reversible color change from red to green was observed at the transition to the isotropic phase.
- XRD and magnetization data indicate no dimerization of radicals in the mesophase.
Conclusions:
- The studied 6-oxoverdazyls self-assemble into ordered columnar structures.
- The observed thermochromism is linked to the phase transition.
- The absence of dimerization suggests stable radical behavior in the mesophase.
