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Decanuclear Ln(10) Wheels and Vertex-Shared Spirocyclic Ln(5) Cores: Synthesis, Structure, SMM Behavior, and MCE Properties

Title
Decanuclear Ln(10) Wheels and Vertex-Shared Spirocyclic Ln(5) Cores: Synthesis, Structure, SMM Behavior, and MCE Properties
Authors
Das, S[Das, Sourav]Dey, A[Dey, Atanu]Kundu, S[Kundu, Subrata]Biswas, S[Biswas, Sourav]Narayanan, RS[Narayanan, Ramakirushnan Suriya]Titos-Padilla, S[Titos-Padilla, Silvia]Lorusso, G[Lorusso, Giulia]Evangelisti, M[Evangelisti, Marco]Colacio, E[Colacio, Enrique]Chandrasekhar, V[Chandrasekhar, Vadapalli]
DGIST Authors
Das, S[Das, Sourav]
Issue Date
2015-11-16
Citation
Chemistry: A European Journal, 21(47), 16955-16967
Type
Article
Article Type
Article
Keywords
Characteristic ValueHomometallic ComplexesLanthanide ComplexLanthanide ComplexesLigandsMacrocyclesMagnetic PropertiesMagnetization ReversalMagnetocaloric Effect (MCE)Magnetocaloric EffectsPentanuclear ComplexesRare Earth ElementsSingle-Molecule MagnetStoichiometric RatioX-Ray DiffractionX Ray Diffraction
ISSN
0947-6539
Abstract
The reaction of a Schiff base ligand (LH3) with lanthanide salts, pivalic acid and triethylamine in 1:1:1:3 and 4:5:8:20 stoichiometric ratios results in the formation of decanuclear Ln10 (Ln=Dy(1), Tb(2), and Gd (3)) and pentanuclear Ln5 complexes (Ln=Gd (4), Tb (5), and Dy (6)), respectively. The formation of Ln10 and Ln5 complexes are fully governed by the stoichiometry of the reagents used. Detailed magnetic studies on these complexes (1-6) have been carried out. Complex 1 shows a SMM behavior with an effective energy barrier for the reversal of the magnetization (Ueff)=16.12(8) K and relaxation time (τo)=3.3×10-5 s under 4000 Oe direct current (dc) field. Complex 6 shows the frequency dependent maxima in the out-of-phase signal under zero dc field, without achieving maxima above 2 K. Complexes 3 and 4 show a large magnetocaloric effect with the following characteristic values: -ΔSm=26.6 J kg-1 K-1 at T=2.2 K for 3 and -ΔSm=27.1 J kg-1 K-1 at T=2.4 K for 4, both for an applied field change of 7 T. Homometallic complexes: The reaction of a multidentate flexible Schiff base ligand (LH3; see figure) with [LnCl3]6 H2O affords homometallic decanuclear complexes, [Ln10(LH)10(κ2-Piv)10] (Ln=Dy, Tb, and Gd), and homometallic pentanuclear complexes, [Ln5(LH)4(μ2-η1η1Piv)4(η1Piv)(S)] (Ln=Dy, Tb, and Gd). The Dy3+ analogues exhibit single-molecule magnet (SMM) behavior, whereas the Gd3+ complexes show a significant magnetocaloric effect (MCE). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
URI
http://hdl.handle.net/20.500.11750/2817
DOI
10.1002/chem.201501992
Publisher
Wiley-VCH Verlag
Files:
There are no files associated with this item.
Collection:
Emerging Materials ScienceBiomimetic Materials Laboratory1. Journal Articles


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