Incorporation of CrIII into a Keggin polyoxometalate as a chemical strategy to stabilize a labile {CrIIIO4} tetrahedral conformation and promote unattended single-ion magnet properties

Polyoxometalates (POMs) provide rigid and highly symmetric coordination sites and can be used as a strategy for the stabilization of magnetic ions. Herein, we report a new member of the Keggin archetype, the Cr-centered Keggin anion [α- CrW12O40]5− (CrW12), with the unusual tetrahedral coordination of CrIII reported for the first time in POMs conferring unattended magnetic properties. POM chemistry has recently presented excellent examples of single-molecule and single-ion magnets (SMMs and SIMs) as well as molecular spin qubits; however, the majority of POM-based SIMs reported to date contain lanthanoid ions. CrW12, as the first example of a chromium(III) SIM, exhibits slow relaxation of magnetization and quantum tunneling with a single- ion magnetic behavior even above 10 K with an energy barrier for the reversal of the magnetization of 3.0 K. The first 3d-metal SIM based on a nonlacunary Keggin anion is the foundation for a new research area in POM chemistry.
Bibliographic reference
Gumerova, N. I., Roller, A., Giester, G., Krzystek, J., Cano, J., & Rompel, A. (2020). Incorporation of CrIII into a Keggin Polyoxometalate as a Chemical Strategy to Stabilize a Labile {CrIIIO4} Tetrahedral Conformation and Promote Unattended Single-Ion Magnet Properties. En Journal of the American Chemical Society (Vol. 142, Issue 7, pp. 3336-3339). American Chemical Society (ACS).