Structure and Magnetic Properties of Homoleptic Trivalent Tris(alkyl)lanthanides

Area of Science:

• Organometallic Chemistry
• Materials Science
• Magnetism

Background:

• Lanthanide compounds are of interest for their unique magnetic properties.
• Solvent-free synthesis offers environmental and practical advantages.
• Understanding structure-property relationships is key for designing new magnetic materials.

Purpose of the Study:

• Synthesize novel homoleptic paramagnetic tris(alkyl)lanthanides.
• Investigate the influence of secondary Ln-H-Si and benzylic interactions on magnetic properties.
• Explore the potential of these compounds in magnetic applications through doping studies.

Main Methods:

• Synthesis of six new tris(alkyl)lanthanide complexes.
• Single-crystal X-ray diffraction for structural analysis.
• Magnetic susceptibility measurements (dc and ac).
• Computational studies (gas-phase calculations) for magnetization and electronic structure.

Main Results:

• Successfully synthesized and characterized Ln{C(SiHMe2)3}3 (1Ln) and Ln{C(SiHMe2)2Ph}3 (2Ln) for Ln = Gd, Dy, Er.
• Structural analysis revealed diverse crystallographic packing and the presence of secondary Ln-H-Si and π-arene interactions.
• Doping 2Dy into 2La enhanced magnetic properties, including higher magnetic susceptibility and anisotropy.
• Ac susceptibility data for doped samples indicated slow magnetic relaxation with a barrier of ~45 K.
• Computational and experimental magnetic moments were in good agreement.

Conclusions:

• The synthesized organolanthanide compounds exhibit tunable magnetic properties influenced by ligand structure and intermolecular interactions.
• Doping strategies can enhance magnetic performance, suggesting potential for single-molecule magnet applications.
• These findings contribute to the fundamental understanding of 4f organometallic magnetism.