Inorganic Chemistry

Rotaxane CoII Complexes as Field-Induced Single-Ion Magnets


Mechanically chelating ligands have untapped potential for the engineering of metal ion properties by providing reliable control of the number, nature and geometry of donor atoms, akin to how a protein cavity controls the properties of bound metal ions. Here we demonstrate this principle in the context of CoII-based single-ion magnets. Using multi-frequency EPR, susceptibility and magnetization measurements we found that these complexes show some of the highest zero field splittings reported for five-coordinate CoII complexes to date. The predictable coordination behavior of the interlocked ligands allowed the magnetic properties of their CoII complexes to be evaluated computationally a priori and our combined experimental and theoretical approach enabled us to rationalize the observed trends. The predictable magnetic behavior of the rotaxane CoII complexes demonstrates that interlocked ligands offer a new strategy to design metal complexes with interesting functionality.


Thumbnail image of 2021 03 10 Cirulli SMM.pdf

Supplementary material

Thumbnail image of 2021_03_09 Cirulli SIM_ESI.pdf
2021 03 09 Cirulli SIM ESI
Thumbnail image of [Co(2)]2+(ClO4-)2.txt
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[Co(2)]2+(ClO4-)2 checkcif
Thumbnail image of [Co(3)]2+(ClO4-)2.txt
Thumbnail image of [Co(3)]2+(ClO4-)2_checkcif.pdf
[Co(3)]2+(ClO4-)2 checkcif
Thumbnail image of Models_de_novo.txt
Models de novo
Thumbnail image of Models_from_xray.txt
Models from xray