Probing Relaxation Dynamics in Five‐Coordinate Dysprosium Single‐Molecule Magnets. Issue 35 (3rd June 2020)

• Record Type: Journal Article
• Authors: Parmar, Vijay S.; Ortu, Fabrizio; Ma, Xiaozhou; Chilton, Nicholas F.; Clérac, Rodolphe; Mills, David P.; Winpenny, Richard E. P.
• Is Part Of: Chemistry. Volume 26:Issue 35(2020)
• Page Start: 7774
• Page End: 7778
• Publication Date: 2020-06-03
• Subjects: aryloxides -- lanthanides -- magnetic anisotropy -- paramagnetic relaxation -- single-molecule magnets; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202001235
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A new family of five‐coordinate lanthanide single‐molecule magnets (Ln SMMs) [Dy(Mes*O)2 (THF)2 X] (Mes*=2, 4, 6‐tri‐tert‐butylphenyl; X=Cl, 1 ; Br, 2 ; I, 3 ) is reported with energy barriers to magnetic reversal >1200 K. The five‐coordinate Dy III ions have distorted square pyramidal geometries, with halide anions on the apex, and two Mes*O ligands mutually trans ‐ to each other, and the two THF molecules forming the second trans ‐ pair. These geometrical features lead to a large magnetic anisotropy in these complexes along the trans ‐Mes*O direction. QTM and Raman relaxation times are enhanced by varying the apex halide from Cl to Br to I, or by dilution in a diamagnetic yttrium analogue. Abstract : Halide influence : A new family of five‐coordinate lanthanide‐based single‐molecule magnets, [Dy(Mes*O)2 (THF)2 X] (Mes*=2, 4, 6‐tri‐tert‐butylphenyl), (X=Cl, Br, I) is reported. While the influence of the different halides on the quantum tunnelling of magnetization and Raman processes is clearly established, the Orbach relaxation is independent of the halide substitution.