Using a Radical Straitjacket to Enforce an Ultrashort Dy-Dy Distance and Thus Enhance Dipolar Interactions in a
Anthony B Carter1,2, Jonas Braun1,3,4, Tilmann Bodenstein3,5,6
1Institute for Inorganic Chemistry (AOC), Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, Karlsruhe 76131, Germany.
Inorganic Chemistry
|December 15, 2025
Summary
We synthesized novel radical-containing lanthanide compounds. These compounds exhibit slow magnetic relaxation, with internal magnetic fields preventing zero-field quantum tunneling of magnetization (ZFQTM).
Area of Science:
- Coordination Chemistry
- Magnetochemistry
- Materials Science
Background:
- Lanthanide-based single-molecule magnets (SMMs) are crucial for developing advanced magnetic materials.
- Controlling magnetic relaxation and quantum tunneling phenomena is key to SMM performance.
- Radical ligands can mediate strong magnetic interactions between metal centers.
Purpose of the Study:
- To synthesize and characterize novel air-stable radical-containing lanthanide compounds.
- To investigate the magnetic properties, specifically slow magnetic relaxation and quantum tunneling.
- To elucidate the role of intramolecular interactions and internal magnetic fields on magnetic relaxation dynamics.
Main Methods:
- Synthesis of lanthanide complexes with 9,10-phenanthrenesemiquinone (phsq) ligands.
- Magnetic susceptibility measurements (dc and ac) to study magnetic behavior.
- Ab initio calculations to determine electronic structure and internal magnetic fields.
- Analysis of magnetic data using multiple theoretical models.
Main Results:
- Three air-stable radical-containing compounds, [MIII2(phsq)4(NO3)2(MeOH)2]·2MeOH (M = Dy, Y, Gd), were synthesized.
- The Dy-containing compound (1) demonstrated single-molecule magnet behavior with relaxation up to 18 K.
- Ab initio calculations revealed significant internal magnetic fields that suppress zero-field quantum tunneling of magnetization (ZFQTM).
- Measurements on a Dy-Y doped sample confirmed the presence of strong ZFQTM in the absence of these internal fields.
Conclusions:
- Strong intramolecular inter-radical interactions effectively isolate lanthanide ions.
- Internal magnetic fields within the Dy complex quench ZFQTM, enhancing SMM performance.
- The Y-doped sample provides crucial evidence for the mechanism suppressing ZFQTM in the pure Dy compound.
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