Pentagonal-Bipyramid Ln(III) Complexes Exhibiting Single-Ion-Magnet Behavior: A Rational Synthetic Approach for a Rigid Equatorial Plane

Abstract

A pentadentate chelating ligand is employed for the facile synthesis of air-stable pentagonal-bipyramid Ln(III) complexes with a rigid equatorial plane. The Dy(III) analogue exhibits single-ion-magnet behavior with U/ k = 70 K under H = 500 Oe.

Structural, magnetic, redox and theoretical characterization of seven-coordinate first-row transition metal complexes with a macrocyclic ligand containing two benzimidazolyl N-pendant arms

“…In the last decade, increased attention has been devoted to the seven-coordinate pentagonal bipyramidal complexes of tran-sition metals 1 and lanthanides [2][3][4][5][6] due to their interesting magnetic properties, which was demonstrated in an increasing number of published articles and reviews concerning this topic. [7][8][9] These seven-coordinate pentagonal bipyramidal complexes especially of Fe II , [10][11][12][13][14][15][16] Co II , 12,[17][18][19][20][21][22] and Ni II , 12,17,23 and more recently also 4d/5d metals like Mo IV/III 24,25 possess large magnetic anisotropy, which is commonly expressed in terms of axial and rhombic zero-field splitting (ZFS) parameters D and E for transition metal complexes.…”

Structure and Magnetic Properties of Two Discrete 3d‐4f Heterometallic Complexes

“…The χ M T values (14.75 cm 3 K mol À 1 ) of complex 1 at 300 K is slightly higher than that (14.17 cm 3 K mol À 1 ) expected for one isolated Dy(III) ion in 6 H 15/2 multiplet ground state, [39,42] which is often seen for Dy(III) complexes. [43][44][45][46] It suggests that the Co(III) ion in 1 is in a low spin state. Upon decreasing the temperature, the χ M T value of 1 decreases slowly from 300 to 100 K with a much faster decrease below 100 K, reaching 8.61 cm 3 K mol À 1 at 2 K. The profile of χ M T versus T plots for 1 might be due to the thermal depopulation of Stark sublevels of Dy(III) ion in 1.…”

Correlation between Slow Magnetic Relaxations and Molecular Structures of Dy(III) Complexes with N5O4 Nona-Coordination

“…Single-molecule magnets (SMMs) are fascinating molecule-based nanomaterials, which are characterized by slow relaxation of magnetization at low temperatures [1][2][3][4][5][6][7][8][9][10]. Magnetic anisotropy plays an essential role in preventing the magnetization flipping; as the orbital angular momentum of 4f electrons is unquenched in the complex formations, each lanthanide(III) (Ln(III)) ion possesses a large magnetic moment correlated with the total angular momentum J, which is defined by the length of the vector summation of the spin angular momentum S and the orbital angular momentum L. The Dy(III) ion is the most fascinating lanthanide ion due to a large total angular momentum of J = 15/2, accompanied by the Kramers characteristic and an oblate type electronic distribution [11][12][13][14][15][16][17][18][19]. The magnetic anisotropy of lanthanide ions is strongly correlated with the electronic repulsion with the crystal field of an appropriate anisotropy; this means an axially stressed crystal field is advantageous for realizing an easy axis anisotropy of the oblate type lanthanide ion.…”

“…In an appropriate anisotropic crystal field, the pair of substates with the highest Ising character was relatively stabilized compared with those of less Ising type pairs to give an easy axial magnetic anisotropy. To achieve such an anisotropic crystal field, the combination of neutral and anionic ligands, with the former located at equatorial positions and the latter located along the z axis, is simple but powerful [18,[20][21][22][23]. This strategy is effective both for light and heavy lanthanide ions with oblate type electronic distributions, such as Ce(III), Nd(III) [24,25], Tb(III), and Dy(III).…”