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A Dysprosium Metallocene Single-Molecule Magnet Functioning at the Axial Limit.

Authors :: Guo FS
Day BM
Chen YC
Tong ML
Mansikkamäki A
Layfield RA
Source :: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2017 Sep 11; Vol. 56 (38), pp. 11445-11449. Date of Electronic Publication: 2017 Jul 13.
Publication Year :: 2017
Abstract: Abstraction of a chloride ligand from the dysprosium metallocene [(Cp <superscript>ttt</superscript> ) <subscript>2</subscript> DyCl] (1 <subscript>Dy</subscript> Cp <superscript>ttt</superscript> =1,2,4-tri(tert-butyl)cyclopentadienide) by the triethylsilylium cation produces the first base-free rare-earth metallocenium cation [(Cp <superscript>ttt</superscript> ) <subscript>2</subscript> Dy] <superscript>+</superscript> (2 <subscript>Dy</subscript> ) as a salt of the non-coordinating [B(C <subscript>6</subscript> F <subscript>5</subscript> ) <subscript>4</subscript> ] <superscript>-</superscript> anion. Magnetic measurements reveal that [2 <subscript>Dy</subscript> ][B(C <subscript>6</subscript> F <subscript>5</subscript> ) <subscript>4</subscript> ] is an SMM with a record anisotropy barrier up to 1277 cm <superscript>-1</superscript> (1837 K) in zero field and a record magnetic blocking temperature of 60 K, including hysteresis with coercivity. The exceptional magnetic axiality of 2 <subscript>Dy</subscript> is further highlighted by computational studies, which reveal this system to be the first lanthanide SMM in which all low-lying Kramers doublets correspond to a well-defined M <subscript>J</subscript> value, with no significant mixing even in the higher doublets.<br /> (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)