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Updated: Jan 11, 2026
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Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
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Peroxide Ligands Support Tetranuclear Lanthanide Ensembles: Synthesis, Structure, Magnetism, and Theoretical Studies
Pawan Kumar1, Jessica Flores Gonzalez2, Hadrien Flichot2
1Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, Telangana 500046, India.
Inorganic Chemistry
|November 13, 2025
Summary
This study details the synthesis of novel tetranuclear lanthanide complexes using peroxide assistance. These complexes exhibit unique magnetic properties, including single-molecule magnet behavior and magnetocaloric effects, explained by theoretical studies.
Area of Science:
- Coordination Chemistry
- Magnetism
- Materials Science
- Theoretical Chemistry
Background:
- Lanthanide complexes are of interest for their unique magnetic and optical properties.
- Peroxide ligands can influence the magnetic behavior and structure of metal assemblies.
- Understanding structure-property relationships is crucial for designing new magnetic materials.
Purpose of the Study:
- To synthesize and characterize novel tetranuclear lanthanide complexes.
- To investigate the magnetic properties, including single-molecule magnet (SMM) behavior and magnetocaloric effects.
- To elucidate the role of peroxide bridges in the observed magnetic phenomena using theoretical calculations.
Main Methods:
- Synthesis of tetranuclear lanthanide complexes ([Ln4(LH2)2(η1-NO3)2(μ3-O2)2(DMF)4]·2NO3·2DMF).
- DC and AC magnetic susceptibility measurements.
- Ab initio CASSCF and DFT calculations.
Main Results:
- Peroxide ions coordinate in a μ3-η2:η2:η2 fashion.
- Dy(III) and Er(III) analogues exhibit field-induced single-molecule magnet (SMM) behavior.
- Gd(III) analogue shows a significant magnetocaloric effect (-ΔS = 27.93 J K−1 kg−1 at 4 K and 13 T).
- Antiferromagnetic and ferromagnetic interactions were observed between Gd(III) and Dy(III) ions, respectively.
- Theoretical calculations support the SMM behavior in the Dy(III) complex, attributing it to peroxide bridges.
Conclusions:
- Peroxide-assisted synthesis yields tetranuclear lanthanide complexes with tunable magnetic properties.
- The studied complexes demonstrate potential as single-molecule magnets and for applications in magnetic refrigeration.
- Theoretical studies confirm the critical role of peroxide ligands in mediating magnetic interactions and SMM behavior.
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