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Osmium(III) Acetylacetonate and Its Missing Polymorph: A Magnetic and Structural Investigation
Arsen Raza1,2, Laura Chelazzi3, Samuele Ciattini3
1Department of Chemistry "Ugo Schiff", DICUS and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Florence, Italy.
Inorganic Chemistry
|August 2, 2024
Summary
This study investigates the magnetic properties of osmium(III) acetylacetonate, [Os(acac)3]. Combining magnetic and spectroscopic techniques, it confirms the structure of a polymorph and characterizes its magnetic behavior, including the easy axis and hyperfine coupling.
Area of Science:
- Inorganic Chemistry
- Solid-State Chemistry
- Magnetochemistry
Background:
- Magnetic properties of 4d and 5d transition metal complexes are underexplored.
- There is a need for multi-technique studies on simple molecules containing these ions.
- Osmium(III) acetylacetonate ([Os(acac)3]) is a suitable candidate for such investigations.
Purpose of the Study:
- To conduct a comprehensive structural and magnetic study on osmium(III) acetylacetonate ([Os(acac)3]).
- To confirm the structure of the beta-polymorph using magnetic and spectroscopic methods.
- To characterize the magnetic behavior, including the easy axis and hyperfine coupling, of the osmium complex.
Main Methods:
- X-ray single crystal diffraction was attempted but did not resolve the structure.
- Direct current (dc) magnetic measurements on powder samples.
- Cantilever torque magnetometry on single crystals.
- Electron paramagnetic resonance (EPR) spectroscopy.
- Alternating current (ac) magnetometry with magnetic dilution.
Main Results:
- The combined magnetic and spectroscopic data provide evidence for the orthorhombic
- The study confirms that all eighth-group acetylacetonate complexes exhibit dimorphism and are isomorphic.
- EPR allowed determination of the easy axis nature of the ground doublet and the first osmium hyperfine coupling.
- Torque magnetometry determined the easy axis orientation along the pseudo C3 axis.
- Ac magnetometry revealed in-field slow magnetization relaxation, further slowed by magnetic dilution.
Conclusions:
- The study successfully characterized the magnetic properties and structure of osmium(III) acetylacetonate ([Os(acac)3]).
- It highlights the utility of combined magnetic and spectroscopic techniques for studying such complexes.
- The findings contribute to understanding the magnetic behavior of 4d and 5d metal ion complexes.
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