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Updated: Sep 7, 2025

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Metal-Metal-Bonded Fe4 Clusters with Slow Magnetic Relaxation
Phoebe R Hertler1, Linus Kautzsch2, Alexander J Touchton1
1Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States.
Abstract:
Reaction of FeBr2 with Li(N═CtBu2) (0.5 equiv) and Zn0 (2 equiv) results in the formation of the formally mixed-valent cluster [Fe4Br2(N═CtBu2)4] (1) in moderate yield. The subsequent reaction of 1 with Na(N═CtBu2) results in formation of [Fe4Br(N═CtBu2)5] (2), also in moderate yield. Both 1 and 2 were characterized by zero-field 57Fe Mössbauer spectroscopy, X-ray crystallography, and superconducting quantum interference device magnetometry. Their tetrahedral [Fe4]6+ cores feature short Fe-Fe interactions (ca. 2.50 Å). Additionally, both 1 and 2 display S = 7 ground states at room temperature and slow magnetic relaxation with zero-field relaxation barriers of Ueff = 14.7(4) and 15.6(7) cm-1, respectively. Moreover, AC magnetic susceptibility measurements were well modeled by assuming an Orbach relaxation process.
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