A Weakly Antiferromagnetically Coupled Biradical Combining Verdazyl with Nitronylnitroxide Units
Pavel V Petunin1,2, Tatyana V Rybalova3,4, Marina E Trusova1
1Research School of Chemistry & Applied Biomedical Sciences, National Research Tomsk Polytechnic University, 30 Lenin ave., Tomsk, 634050, Russia.
Chempluschem
|January 17, 2020
Summary
A novel antiferromagnetically coupled biradical was synthesized, exhibiting unique properties and forming distinct crystalline structures. Intermolecular interactions were found to be significantly stronger than intramolecular ones, offering insights for future research.
Area of Science:
- Organic chemistry
- Materials science
- Magnetochemistry
Background:
- Antiferromagnetic (AFM) coupling is crucial for developing advanced magnetic materials.
- Heterobiradicals offer a platform to study intramolecular and intermolecular magnetic interactions.
- Understanding radical properties in solution and solid states is key for material design.
Purpose of the Study:
- To synthesize and characterize a novel AFM-coupled biradical.
- To investigate the solution and solid-state properties of the synthesized biradical.
- To explore the influence of crystalline form on magnetic interactions.
Main Methods:
- Sonogashira coupling for synthesis.
- Solution-based characterization of radical properties.
- SQUID magnetization measurements for magnetic properties.
- Density Functional Theory (DFT) calculations for theoretical insights.
Main Results:
- Successful synthesis of an oxoverdazyl and nitronylnitroxide based heterobiradical in 46% yield.
- The biradical displayed distinct properties of both radical components in solution.
- Two different crystalline forms (Form I and Form II) were obtained depending on the solvent.
- SQUID measurements revealed stronger intermolecular (zJinterII /kB =-11.5 K) than intramolecular (JintraII /kB =-2.1 K) exchange interactions in Form II.
- DFT calculations elucidated the observed magnetic phenomena.
Conclusions:
- The synthesized heterobiradical exhibits tunable properties based on its crystalline form.
- Intermolecular magnetic interactions significantly dominate over intramolecular ones in the solid state.
- Form I is identified as a promising candidate for further detailed investigations due to its advantageous properties.
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