Influence of pressure on a dysprosocenium single-molecule magnet

Abstract

The effects of external pressure on a high-performing dysprosocenium single-molecule magnet are investigated using a combination of X-ray diffraction, magnetometry and theoretical calculations. The effective energy barrier (Ueff) decreases from...

Reversible Pressure‐Magnetic Modulation in a Tetrathiafulvalene‐Based Dyad Piezochromic Dysprosium Single‐Molecule Magnet**

“…Application of high-pressure tends to close the hysteresis loop in field (δ = 650 0e at H = 1000 Oe for P = 0 GPa and (δ = 400 0e at H = 1000 Oe for P = 1.17 GPa) (Figure S28) in agreement with the increase of the under energy barrier mechanisms (QTM and Raman). The previous magnetic investigation in frozen solution of Dy [44] and for diluted 162 Dy [48] undoubtedly demonstrated the presence of significant intermo-Figure 5. Arrhenius plots of the relaxation time in zero applied magnetic field (full symbols) and at 1000 Oe (empty symbols) for 162 Dy at P = 0 GPa (black), P = 0.31 GPa (green), P = 1.17 GPa (red) and back to P = 0 GPa (gray).…”

“…Nevertheless, in such examples the applied pressure induced the loss of crystallinity due to the release of solvent molecules [42] or phase transition [43] and the effect of intermolecular and hyperfine interactions could not be quantitatively taken into account. [44] The mononuclear complex of formula [Dy(tta) 3 (L)]•C 6 H 14 (tta À = 2-2-thenoyltrifluoroacetonate and L = 4,5-bis(propylthio)tetrathiafulvalene-2-(2-pyridyl)benzimidazole-methyl-2-pyridine) was selected from our library of compounds for high pressure studies because its magnetic properties are experimentally and computationally well-known, [45] magnetic dilutions and isotopic enrichment studies were performed [46][47][48] as well as spectroelectrochemistry investigations. [49] Moreover the nuclear spin free 162 Dy(III) (I = 0) ion was chosen to cancel the hyperfine coupling and to diminish the under-barrier magnetic relaxation mechanisms.…”

Measurement of the Quantum Tunneling Gap in a Dysprosocenium Single-Molecule Magnet

“…29 Magnetization sweeps for various different concentrations of [Dy(Cp ttt ] was prepared using methodology described previously. 23 A 27.5 mg crystalline sample was pulverized in a mortar and pestle to a microcrystalline powder and secured inside a 5 mm flame-sealed NMR tube using 20.3 mg of eicosane. DCM and DFB were distilled from CaCl 2 and stored over 3 Å and 4 Å sieves, respectively.…”

“…The field sweeps were performed at 1.8 and 4 K, and therefore, only the ground Kramers doublet is relevant and [Dy­(Cp ttt ) 2 ]­[B­(C 6 F 5 ) 4 ] can be modeled using eq . In the effective spin-1/2 model, the value of | m – m ′| = 1 and for [Dy­(Cp ttt ) 2 ]­[B­(C 6 F 5 ) 4 ] g = diag­(0, 0, 19.98) . As our measurements are performed on polycrystalline or solution samples, we must integrate the magnetic field over all orientations.…”

“…In the effective spin-1/2 model, the value of | m – m ′| = 1 and for [Dy(Cp ttt ) 2 ][B(C 6 F 5 ) 4 ] g = diag(0, 0, 19.98). 23 As our measurements are performed on polycrystalline or solution samples, we must integrate the magnetic field over all orientations. Due to the very strong eas y -axis anisotropy of the ground doublet of [Dy(Cp ttt ) 2 ][B(C 6 F 5 ) 4 ], this can be obtained analytically by integrating eq 2 between the hard-plane and the eas y -axis: where …”