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Updated: Jun 22, 2026
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Modelling the magnetic behaviour of square-pyramidal Co(II)5 aggregates: tuning SMM behaviour through variations in
Frederik Klöwer1, Yanhua Lan, Joscha Nehrkorn
1Institut für Anorganische Chemie der Universität Karlsruhe, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany.
Abstract:
Three new mu4-bridged Co(II)5 clusters with similar core motifs have been synthesised with the use of N-tert-butyldiethanolamine (tbdeaH2) and pivalic acid (piv): [Co(II)5(mu4-N3)(tbdea)2(mu-piv)4(piv)(CH3CN)2].CH3CN (1), [Co(II)5(mu4-Cl)(Cl)(tbdea)2(mu-piv)4(pivH)2] (2) and [Co(II)5(mu4-N3)(Cl)(tbdea)2(mu-piv)4(pivH)2] (3). Magnetic measurements were performed for all three compounds. It was found that while the chloride-bridged cluster 2 does not show an out-of-phase signal, which excludes single-molecule magnet (SMM) behaviour, the azide-bridged compounds 1 and 3 show out-of-phase signals as well as frequency dependence of the ac susceptibility, as expected for SMMs. We confirmed that 1 is a SMM with zero-field quantum tunnelling of the magnetisation at 1.8 K. Compound 3 is likely a SMM with a blocking temperature well below 1.8 K. We established a physical model to fit the chiT versus T and M versus B curves of the three compounds to reproduce the observed SMM trend. The analysis showed that small changes in the ligand shell modify not only the magnitude of exchange constants, but also affect the J and g matrices in a non-trivial way.
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