1. Radical Dimerization in a Plastic Organic Crystal Leads to Structural and Magnetic Bistability with Wide Thermal Hysteresis
- Author
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Stephen Hill, Minyoung Jo, Chongin Pak, Richard T. Oakley, Jeff Lengyel, Ivan Hung, Samuel M. Greer, Yan-Yan Hu, Alexander S. Filatov, Johannes McKay, Michael Shatruk, Elvis Maradzike, Sebastian A. Stoian, Alina Dragulescu-Andrasi, Ashfia Huq, Kristina Lekin, A. Eugene DePrince, and Xiang Li
- Subjects
Phase transition ,Chemistry ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,Crystal structure ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,law.invention ,Crystallography ,Paramagnetism ,Colloid and Surface Chemistry ,law ,Phase (matter) ,Plastic crystal ,Electron paramagnetic resonance ,Powder diffraction - Abstract
The nitroxyl radical 1-methyl-2-azaadamantane N-oxyl (Me-AZADO) exhibits magnetic bistability arising from a radical/dimer interconversion. The transition from the rotationally disordered paramagnetic plastic crystal, Me-AZADO, to the ordered diamagnetic crystalline phase, (Me-AZADO)2, has been conclusively demonstrated by crystal structure determination from high-resolution powder diffraction data and by solid-state NMR spectroscopy. The phase change is characterized by a wide thermal hysteresis with high sensitivity to even small applied pressures. The molecular dynamics of the phase transition from the plastic crystal to the conventional crystalline phase has been tracked by solid-state (1H and 13C) NMR and EPR spectroscopies.
- Published
- 2019