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Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Structure and property correlations in heavy atom radical conductors
Alicea A Leitch1, Xueyang Yu, Stephen M Winter
1Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Journal of the American Chemical Society
|May 6, 2009
Summary
This study details the synthesis and characterization of thia/selenazyl radicals. Differences in crystal packing lead to distinct electrical and magnetic properties, with monoclinic structures showing higher conductivity and antiferromagnetic coupling.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Organic Electronics
Background:
- Resonance-stabilized heterocyclic radicals are of interest for their electronic properties.
- Understanding structure-property relationships is crucial for designing new materials.
Purpose of the Study:
- To synthesize and characterize novel thia/selenazyl radicals (1a-4a).
- To investigate the impact of crystal packing on their solid-state electrical and magnetic properties.
- To correlate structural features with conductivity and magnetic behavior.
Main Methods:
- Single-crystal X-ray diffraction for structural analysis.
- Variable-temperature conductivity measurements.
- Variable-temperature magnetic susceptibility measurements.
- Extended Huckel theory and density functional theory calculations.
Main Results:
- Four thia/selenazyl radicals (1a-4a) were synthesized and characterized.
- Two distinct crystal packing motifs were observed: orthorhombic (1a, 3a) and monoclinic (2a, 4a).
- Monoclinic structures exhibited higher electrical conductivity (sigma(298 K) > 10(-3) S cm(-1)) and strong antiferromagnetic coupling.
- Conductivity increased significantly under applied pressure.
- Theoretical calculations provided insights into the conductive and magnetic properties.
Conclusions:
- Crystal packing significantly influences the electronic and magnetic properties of these radicals.
- The monoclinic packing, maximizing Se-Se contacts, leads to enhanced conductivity and antiferromagnetism.
- These findings offer a basis for designing organic materials with tunable electronic and magnetic characteristics.
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