Slow Relaxation of the Magnetization in Dysprosium–Aluminum Metallacrowns

A series of DyIII-AlIII metallacrowns (MC) with the ligand salicylhydroxamic acid (H3shi) were investigated for magneto-structural interactions. The four MCs demonstrate that slight variations in reaction conditions and molecular components can lead to different classes of MCs. The DyIII-AlIII MCs include an archetype Dy III Al III 4 [12-MC-4], the dimer Dy III 2 Al III 8 [12-MC-4] 2, a [3.3.1] metallacryptand (MCr) Dy III Al III 6 [3.3.1], and Dy III 2 Al III 6 [18-MC-6], representing a new type of MC. Dy III 2 Al III 6 [18-MC-6] consists of a MC ring with six ring AlIII ions that have an octahedral propeller configuration with a stereoisomer pattern ΔΛΛΛΔΔ about the MC ring. The 18-MC-6 captures a [DyIII 2(μ3-OH)2]4+ core, where each DyIII ion is nine-coordinate with muffin geometry (C s). Both the static and dynamic magnetic properties of the complexes were investigated. Models of the static magnetic data reveal that Dy III Al III 4 [12-MC-4] and Dy III 2 Al III 8 [12-MC-4] 2 do not have a significant axial ligand field, as the DyIII ions have a square antiprism geometry (D 4d). However, a similar analysis demonstrates that Dy III Al III 6 [3.3.1] and Dy III 2 Al III 6 [18-MC-6] do have a significant axial component to the ligand field, as the DyIII ions in these complexes have spherical capped square antiprism (C 4v) or muffin geometry, respectively. The DyIII geometry differences lead to differing dynamic magnetic susceptibility behavior. Dy III Al III 4 [12-MC-4] and Dy III 2 Al III 8 [12-MC-4] 2 do not display a frequency-dependent out-of-phase magnetic susceptibility signal in the absence of a static magnetic field. A frequency-dependent signal is observed only with the application of an 800 Oe magnetic field. However, Dy III Al III 6 [3.3.1] and Dy III 2 Al III 6 [18-MC-6] do exhibit SMM behavior in the absence and presence of a static magnetic field. For Dy III Al III 6 [3.3.1] and Dy III 2 Al III 6 [18-MC-6], the effective energy barrier to magnetization relaxation (U eff) with an 800 Oe magnetic field is 59 ± 2 and 35 ± 2 cm-1 with τ0 = 2.5 ± 0.7 × 10-8 and 3.5 ± 1.1 × 10-8 s, respectively.

Authors

Matthias Zeller (ORCID: https://orcid.org/0000-0002-3305-852X)
Adrien L. Hess
M. Solzi (ORCID: https://orcid.org/0000-0002-9912-4534)
Elena Garlatti (ORCID: https://orcid.org/0000-0002-0370-0534)
Curtis M. Zaleski (ORCID: https://orcid.org/0000-0003-4831-2911)
Francesco Cugini (ORCID: https://orcid.org/0000-0003-0275-1986)
Simone Chicco (ORCID: https://orcid.org/0000-0001-8063-7324)
Stefano Carretta (ORCID: https://orcid.org/0000-0002-2536-1326)
Jordan R. Travis
Rachel E. Rheam

Institutions

University of Parma (IT)
Shippensburg University (US)
Purdue University West Lafayette (US)
Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca (IT)
National Interuniversity Consortium of Materials Science and Technology (IT)

Publication Details

Journal: ACS Omega
Published: 2025-11-14
DOI: https://doi.org/10.1021/acsomega.5c07724
Citations: 1
Primary Topic: Magnetism in coordination complexes
Type: article
Field-Weighted Citation Impact: 0.43

Slow Relaxation of the Magnetization in Dysprosium–Aluminum Metallacrowns

Authors

Institutions

Publication Details

Slow Relaxation of the Magnetization in Dysprosium–Aluminum Metallacrowns

Slow Relaxation of the Magnetization in Dysprosium–Aluminum Metallacrowns

Abstract

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