Synthesis, structure and magnetic properties of unsymmetrical dodecanuclear Mn–Ln clusters

Mereacre, Valeriu; Prodius, Denis; Ako, Ayuk M.; Kaur, Narpinder; Lipkowski, Janusz; Simmons, Charles J.; Dalal, Naresh S.; Geru, Ion; Anson, Christopher E.; Powell, Annie K.; Turta, Constantin

doi:10.1016/j.poly.2008.04.037

Cited by 36 publications

(14 citation statements)

References 31 publications

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“…Nevertheless, research in recent years has provided a good number of compounds containing both 3d and 4f ions showing slow relaxation of the magnetization [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. In the case of isolated molecules it has been possible to begin to understand the roles played by the two different sorts of ions in producing magnetically interesting molecules.…”

Section: F-3d Systemsmentioning

confidence: 99%

Strategies towards single molecule magnets based on lanthanide ions

Sessoli

Powell

2009

Coordination Chemistry Reviews

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1,431

707

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Section: F-3d Systemsmentioning

confidence: 99%

Strategies towards single molecule magnets based on lanthanide ions

Sessoli

Powell

2009

Coordination Chemistry Reviews

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1,431

707

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“…(3), Mn(2), Mn(4), Mn(6) and Mn( 8 acetate and lanthanide nitrates in the presence of excess PhCOOH. 208 The simplified metallic cores of 119-120 are shown in Fig. 102.…”

Section: Mnmentioning

confidence: 99%

Structural motifs and topological representation of Mn coordination clusters

2010

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Polynuclear coordination clusters have become of particular interest in recent times as a result of their relevance to bioinorganic chemistry and to the special area of molecule-based magnetic materials where cluster compounds behave as single-molecule magnets (SMMs). In this review we have focused on describing Mn coordination cluster complexes. Adopting our topological approach for the description of coordination clusters we present a means of classifying the structural motifs found in manganese clusters which range in nuclearity from 5 to 84, as well as some representative heterometallic Mn-M (M = K, Na, Ca, Sr, Ln) cluster complexes that have been reported. This sheds new light on the classification of the types of core structure accessible which, in turn, provides a useful means for developing the so-far missing magneto-structural correlation algorithm for these finite 0-D systems (212 references).

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“…Indeed, the Nd(III) ion has been included in 3d/Nd clusters in the quest for SMMs, but only a few cases of slow relaxation have been reported: in a [Mn 4 Nd 2 ] cluster, a non-zero χ″(T, ω) was detected at low temperatures, 18 which was associated with the presence of the neodymium light rare earth, and in [Mn 10 Nd 4 ] 19 and [Mn 11 Nd 4 ] 20 asymmetric clusters, the same feature was observed. Slow relaxation in the Ni/Nd single chain magnet has been reported in only one case.…”

Section: Introductionmentioning

confidence: 99%

Structural and magnetic properties of some lanthanide (Ln = Eu(iii), Gd(iii) and Nd(iii)) cyanoacetate polymers: field-induced slow magnetic relaxation in the Gd and Nd substitutions

et al. 2014

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The lanthanide(iii) cyanoacetate complexes of the formula {[Ln2(CNCH2COO)6(H2O)4]·2H2O}n, where Ln = Eu (), Gd (), Nd (), have been prepared and characterized by X-ray diffraction analysis. Complexes and are isostructural and differ from the binding scheme of the neodymium compound , structurally described earlier. In all cases, the cyano group of the cyanoacetate ligand is not coordinated to the lanthanide cation. The carboxylic groups exhibit different binding modes: 2-bidentate-chelating, 2-bidentate and 2-tridentate-chelating bridging for and , and 4-bidentate and 2-tridentate-chelating bridging for the complex . The Eu compound shows field induced paramagnetism, as expected for a non-magnetic ground state with mixing from higher states. Combining the dc magnetization and luminescence measurements the spin-orbit coupling constant λ = 343 ± 4 cm(-1) was found, averaged over the two different sites for Eu in the lattice. In the Gd complex , a crystal field splitting of D/kB = -0.11 ± 0.01 K has been found for the S = 7/2 multiplet of the Gd(iii) ion. No slow relaxation at H = 0 is observed because the low anisotropy barrier allows fast spin reversal through classical processes. The application of an external magnetic field induces two slow relaxation processes. It is argued that the first relaxation rate is caused by the resonant phonon trapping (RPT) mechanism, while the second, slower relaxation rate is due to the lifting of the Kramers degeneracy on the ground state. For compound heat capacity and dc susceptibility measurements indicate that at very low temperatures the ground state Kramers doublet has strong single ion anisotropy. The energy to the next excited doublet ΔZFS/kB = 104 K has been calculated by ab initio calculation methods. The g* tensor has also been calculated, showing that it has predominant anisotropy along the z-axis, and there is an important transversal component. At H = 0 quantum tunnelling is an effective mechanism in producing a fast relaxation to equilibrium at temperatures above 1.8 K. The dipolar or exchange interactions and a sizable transverse anisotropy component in the ground state enhance the quantum tunneling probability. Under an external applied field, two slow relaxation processes appear: above 3 K the first relaxation mechanism is of the Orbach type, with an activation energy U/kB = 27 K; the slower relaxation is caused by the direct relaxation process from the ground state to the Kramers split levels by the applied field.

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Synthesis, structure and magnetic properties of unsymmetrical dodecanuclear Mn–Ln clusters

Cited by 36 publications

References 31 publications

Strategies towards single molecule magnets based on lanthanide ions

Strategies towards single molecule magnets based on lanthanide ions

Structural motifs and topological representation of Mn coordination clusters

Structural and magnetic properties of some lanthanide (Ln = Eu(iii), Gd(iii) and Nd(iii)) cyanoacetate polymers: field-induced slow magnetic relaxation in the Gd and Nd substitutions

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