ja5b03710_si_001.pdf (1.28 MB)
Record High Single-Ion Magnetic Moments Through 4fn5d1 Electron Configurations in the Divalent Lanthanide Complexes [(C5H4SiMe3)3Ln]−
journal contribution
posted on 2015-08-12, 00:00 authored by Katie
R. Meihaus, Megan E. Fieser, Jordan F. Corbey, William J. Evans, Jeffrey R. LongThe recently reported series of divalent
lanthanide complex salts,
namely [K(2.2.2-cryptand)][Cp′3Ln] (Ln = Y, La,
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm; Cp′ = C5H4SiMe3) and the analogous trivalent complexes,
Cp′3Ln, have been characterized via dc and ac magnetic
susceptibility measurements. The salts of the complexes [Cp′3Dy]− and [Cp′3Ho]− exhibit magnetic moments of 11.3 and 11.4 μB, respectively, which are the highest moments reported to
date for any monometallic molecular species. The magnetic moments
measured at room temperature support the assignments of a 4fn+1 configuration for Ln = Sm, Eu, Tm and a 4fn5d1 configuration for Ln = Y,
La, Gd, Tb, Dy, Ho, Er. In the cases of Ln = Ce, Pr, Nd, simple models
do not accurately predict the experimental room temperature magnetic
moments. Although an LS coupling scheme is a useful
starting point, it is not sufficient to describe the complex magnetic
behavior and electronic structure of these intriguing molecules. While
no slow magnetic relaxation was observed for any member of the series
under zero applied dc field, the large moments accessible with such
mixed configurations present important case studies in the pursuit
of magnetic materials with inherently larger magnetic moments. This
is essential for the design of new bulk magnetic materials and for
diminishing processes such as quantum tunneling of the magnetization
in single-molecule magnets.