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Magnetically bistable cobalt-dioxolene complexes with a tetradentate N-donor base
Maxim G Chegerev1, Denis V Korchagin2, Gennady V Shilov2
1Institute of Physical and Organic Chemistry, Southern Federal University, Stachki Avenue, 194/2, 344090 Rostov-on-Don, Russia. mchegerev@sfedu.ru.
Dalton Transactions (Cambridge, England : 2003)
|October 26, 2022
Summary
This study reports new cobalt-dioxolene complexes exhibiting unique magnetic properties. These compounds demonstrate field-induced single-ion magnet behavior, offering insights into molecular magnetism.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Magnetochemistry
Background:
- Cobalt-dioxolene complexes are of interest due to their tunable electronic and magnetic properties.
- Understanding the interplay between metal oxidation states and ligand redox states is crucial for designing novel magnetic materials.
Purpose of the Study:
- To synthesize and characterize a new family of cobalt-dioxolene complexes.
- To investigate their magnetic properties, including spin states and single-ion magnet behavior.
- To elucidate the electronic structures and bonding in these complexes.
Main Methods:
- Synthesis of cobalt-dioxolene complexes: [(Me2TPA)Co(36-DBCat)] (1), [(Me2TPA)Co(36-DBCat)](PF6) (2), and [(Me2TPA)Co(diox-(OMe)3)](BPh4) (3).
- Variable temperature single crystal X-ray diffraction analysis.
- Magnetic characterization including variable temperature magnetic susceptibility measurements.
- Density Functional Theory (DFT) and SA-CASSCF/NEVPT2 calculations for electronic structure analysis.
Main Results:
- Complex 1 exists as hexa- and pentacoordinated isomers (1a and 1b), featuring high-spin divalent cobalt and dianionic catecholate ligands.
- Complex 2 exhibits a thermally induced valence-tautomeric transition (ls-CoIII-36-DBCat ⇄ hs-CoII-36-DBSQ) in the solid state at 175 K.
- Complexes 1a, 1b, and 3 display field-induced single-ion magnet behavior.
- DFT and SA-CASSCF/NEVPT2 calculations provide insights into the electronic structures of the studied complexes.
Conclusions:
- The synthesized cobalt-dioxolene complexes display diverse coordination environments and redox states.
- These complexes demonstrate promising single-ion magnet characteristics, influenced by ligand structure and metal spin state.
- The study provides a comprehensive understanding of the structure-property relationships in this class of magnetic materials.
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