Pentanuclear Dysprosium Hydroxy Cluster Showing Single-Molecule-Magnet Behavior

Abstract

A pentanuclear dysprosium hydroxy cluster of composition [Dy 5(mu 4-OH)(mu 3-OH) 4(mu-eta (2)-Ph 2acac) 4(eta (2)-Ph 2acac) 6] ( 1; Ph 2acac = dibenzoylmethanide) was prepared starting from [DyCl 3.6H 2O] and dibenzoylmethane. Both static (dc) and dynamic (ac) magnetic properties of 1 have been studied. Below 3 K, the appearance of slow relaxation of the magnetization typical for single-molecule magnets is seen, even if no hysteresis effects on the M vs H data are observed above 1.8 K.

Modulating the Slow Relaxation Dynamics of Binuclear Dysprosium(III) Complexes through Coordination Geometry

“…However, the out-of-phase signals (χ M ") for complex 2 do not show the peak maxima in the mentioned temperature range. Therefore, Debye model and Equation (2) were used to calculate energy barrier and relaxation time [36] ln(χ /χ ) = ln(ωτ 0 ) + U eff /kT (2) From the best fitting, the value of energy barrier and relaxation time were calculated as U eff = 9.7 K and τ 0 = 1.4 × 10 −6 s, respectively ( Figure S11), and found to be in good agreement with the expected value of 10 −6 -10 −11 for a SMM [37][38][39].…”

“…From the best fitting, the value of energy barrier and relaxation time were calculated as Ueff = 9.7 K and τ0 = 1.4 × 10 −6 s, respectively ( Figure S11), and found to be in good agreement with the expected value of 10 −6 -10 −11 for a SMM [37][38][39]. The reduced magnetization data (M/Nµ B vs. H) of the complexes were collected at 2, 6 and 10 K. For 1 and 2, with increase in field M/Nµ B values increase sharply and attained the values of 11.5 and 11.2 Nµ B respectively ( Figure 2 and Figure S7), which are in good agreement with the theoretical value for Dy III -based SMMs [8].…”

Rare‐Earth Metal Oxo/Hydroxo Clusters – Synthesis, Structures, and Applications

“…We and others have established the synthesis of pentanuclear lanthanide hydroxo clusters by treatment of the trichlorides of the smaller lanthanides [LnCl 3 ·(H 2 O) n ] (n = 6, 7) with dibenzoylmethane (Ph 2 acacH) in organic solvents in the presence of an organic base such as triethylamine or KOtBu. Another route to these compounds is by treatment of [Ln(Ph 2 acac) 3 10 ] (Ln = Y, [10] Nd, [49] Eu, [50][51][52][53] Tb, [52] Dy, [54] Ho, [53] Er, [49,55] Yb; [49] Scheme 3), in which the lanthanide atoms build up a square pyramidal scaffold by occupying its vertices (Figure 6), were obtained. In each of these structures, the square base face of the pyramid is capped by one μ 4 -oxygen atom, whereas its four triangular faces are capped by one μ 3 -oxygen moiety each.…”

“…The structure adopted by the rare-earth atoms is similar to that of the earlier reported alkoxide clusters [Ln 5 (μ 5 -O)(OiPr) 13 ]; [42] however, the capping 10 ]. [54] Hydrogen atoms are omitted for clarity. .…”

Recent Progress in the Realm of Homonuclear Ln6 Single molecule magnets: Structural Overview and Synthetic Approaches

“…Huge enthusiasm followed the stupendous discovery of this dodecametallic manganese-acetate cage [Mn 12 O 12 (OAc) 16 (H 2 O) 4 ], which for the first time showed the unique property of retaining the magnetization for long time periods in the absence of any external magnetic field. This famous transition metal coordination compound established itself as the progenitor of an enormous family of magnetic materials, known as single molecule magnets (SMMs) (Zaleski et al, 2004;Gatteschi et al, 2006;Lin et al, 2008;Costes et al, 2008;Chibotaru et al, 2008;Gamer et al, 2008;Zheng et al, 2009;Burrow et al, 2009;Xu et al, 2010;Ishikawa et al, 2003;Luzon et al, 2008;Lin et al, 2009;AlDamen et al, 2008;Cardona-Serra et al, 2012;Joarder et al, 2012), which could be precisely defined as such molecular species, essentially aggregates possessing both non-negligible high-spin ground state (S) and uniaxial (negative) Ising-like magnetic anisotropy |D| (taking into account the Hamiltonian: H = DS z 2 ), leading to an anisotropy energy barrier (U) (S 2 |D| or (S 2 -1/4)|D| for integer or half integer spins respectively, for the reversal of magnetization (Habib et al, 2013;Chakov et al, 2006). One remarkable aspect is that, this relationship applies satisfactory to 3d and 4d-transition metal systems but is unable to represent correctly the experimental barriers in lanthanide complexes.…”