Administratieve knelpunten belemmeren innovatie van management accounting

Administratieve knelpunten belemmeren innovatie van management accountin

Record High Single-Ion Magnetic Moments Through 4f(n)5d(1) Electron Configurations in the Divalent Lanthanide Complexes [(C5H4SiMe3)3Ln]⁻.

The 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 4f(n+1) configuration for Ln = Sm, Eu, Tm and a 4f(n)5d(1) 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

Record High Single-Ion Magnetic Moments Through 4f(n)5d(1) Electron Configurations in the Divalent Lanthanide Complexes [(C5H4SiMe3)3Ln]⁻.

The 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 4f(n+1) configuration for Ln = Sm, Eu, Tm and a 4f(n)5d(1) 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

Varying the Lewis Base Coordination of the Y2N2Core in the reduced dinitrogen complexes {[(Me3Si)2N]2(L)Y}2(μ-η2:η2-N2) (L = benzonitrile, pyridines, triphenylphosphine oxide, and trimethylamine N-oxide)

The effect of the neutral donor ligand, L, on the Ln2N2 core in the (N═N)2– complexes, [A2(L)Ln]2(μ-η2:η2-N2) (Ln = Sc, Y, lanthanide; A = monoanion; L = neutral ligand), is unknown since all of the crystallographically characterized examples were obtained with L = tetrahydrofuran (THF). To explore variation in L, displacement reactions between {[(Me3Si)2N]2(THF)Y}2(μ-η2:η2-N2), 1, and benzonitrile, pyridine (py), 4-dimethylaminopyridine (DMAP), triphenylphosphine oxide, and trimethylamine N-oxide were investigated. THF is displaced by all of these ligands to form {[(Me3Si)2N]2(L)Y}2(μ-η2:η2-N2) complexes (L = PhCN, 2; py, 3; DMAP, 4; Ph3PO, 5; Me3NO, 6) that were fully characterized by analytical, spectroscopic, density functional theory, and X-ray crystallographic methods. The crystal structures of the Y2N2 cores in 2–5 are similar to that in 1 with N–N bond distances between 1.255(3) Å and 1.274(3) Å, but X-ray analysis of the N–N distance in 6 shows it to be shorter: 1.198(3) Å