Slow magnetic relaxation in Ni–Ln (Ln = Ce, Gd, Dy) dinuclear complexes

Abstract

Unusual magnetic behaviour is observed in compounds with three Cl ligands in fac-mode coordination to dysprosium, cerium and even gadolinium.

Modulation of Slow Magnetic Relaxation in Gd(III)‐Tetrahalosemiquinonate Complexes

“…Where A represents direct relaxation coefficient, τ QTM −1 is the rate of QTM, τ 0 −1 is the Orbach coefficient, U eff the effective energy barrier to Orbach relaxation, C the Raman coefficient and n the Raman exponent. It should be noted that the relaxation behavior of Gd‐SMMs previously reported has been fit using both Raman and Orbach relaxation processes [50–57] . The EPR measurements for 1 clearly indicate that | D Gd | 0.10 cm −1 , implying an extension of the ground S =3 multiplet of ca.…”

“…It should be noted that the relaxation behavior of Gd-SMMs previously reported has been fit using both Raman and Orbach relaxation processes. [50][51][52][53][54][55][56][57] The EPR measurements for 1 clearly indicate that j D Gd j �0.10 cm À 1 , implying an extension of the ground S = 3 multiplet of ca. 1.5 cm À 1 .…”

On new solvatomorphs of the metalloligand [Ni(o-van-en)]

“…As a result of its shape the [Ni(o-van-en)] complex molecule possesses a compartment located between the two oxygen atoms from deprotonated hydroxyl groups and two methoxy groups. This compartment, as mentioned above, can serve for accommodation of an additional metal atom such as a lanthanide [11,36] or alkali metal [37,38]. In the absence of such a metal atom the resulting space is (possibly partially) occupied by a hydrogen-bonded solvate molecule, sometimes slightly displaced from the plane of the complex.…”

“…Within our broader study of magnetically active complexes, we have prepared the intended as a building block for the preparation of magnetically active bimetallic Ni-Ln complexes (Ln = lanthanoids) [11]; the rationale for this approach has been described in the literature [12][13][14]. Briefly, the transition-metal complex of the deprotonated Schiff base acts as a metalloligand capable of further incorporating a lanthanoid center in the outer cavity to yield a heterobimetallic (Tr-Ln) system with intriguing properties.…”

Triangulo-{ErIII3} complex showing field supported slow magnetic relaxation

“…Single molecule magnets (SMMs) and single ion magnets (SIMs) are usually coordination compounds that exhibit slow relaxation of their magnetization in the absence of an external magnetic eld at a molecular level. 1 Since the discovery of a dodecanuclear manganese cluster as a SMM, 2 a plethora of SMMs were made of homometallic [3][4][5][6][7] and heterometallic [8][9][10][11][12][13][14][15] transition metals and have been reported. Lanthanides entered into this spectacular eld of molecular magnetism owing to their large magnetic moments and huge magnetic anisotropy despite their weak exchange interactions due to the efficient shielding of the unpaired electrons in the 4f orbitals.…”