Magnetocaloric effect and slow magnetic relaxation in peroxide-assisted tetranuclear lanthanide assemblies

Kumar, Pawan and Flores Gonzalez, Jessica and Sahu, Prem Prakash and Singh, Saurabh Kumar and et al, . (2022) Magnetocaloric effect and slow magnetic relaxation in peroxide-assisted tetranuclear lanthanide assemblies. Inorganic Chemistry Frontiers, 9 (19). pp. 5072-5092. ISSN 2052-1553

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Abstract

The synthesis, structure and magnetism of tetranuclear complexes, [Ln4(LH2)2(η1-Piv)2(η2-Piv)2(μ3-O2)2(H2O)2]·2MeOH (1, Ln = GdIII; 2,Ln = TbIII; 3, Ln = DyIII; and 4, Ln = ErIII) (LH4 = 6-((bis(2-hydroxyethyl)amino)-N′-(2-hydroxybenzylidene)picolinohydrazide) (piv = pivalate ion) are reported. Interestingly, the formation of these tetranuclear assemblies is assisted by two side-on coordinating peroxide ligands which bind in a μ3-η2:η2:η2 fashion. DC magnetic behaviour revealed the existence of a dominating but weak intramolecular antiferromagnetic interaction in the cases of 1, 2, and 4, while a small structural change in complex 3 turns this into a ferromagnetic interaction. We have investigated the magnetothermal behaviour of 1 which shows a magnetocaloric effect with the value of maximum entropy change of −ΔSm = 33.60 J K−1 kg−1 at 4 K (ΔH = 13-0 T). This is close to the calculated value of 36.45 J K−1 kg−1. The ac magnetic susceptibility study confirms zero-field out-of-phase magnetic susceptibility signals only for 3 which get well resolved on the application of a 1 kOe dc magnetic field. The energy barrier for the Orbach process of spin reversal was found to be 23 K (τ0 = 9 × 10−7 s). We also report detailed theoretical studies to rationalize and understand the observed magnetic behaviour. © 2022 The Royal Society of Chemistry.

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IITH Creators:

IITH Creators	ORCiD
Singh, Saurabh Kumar	UNSPECIFIED

Item Type:

Article

Additional Information:

We thank the Department of Science and Technology (DST), India, and acknowledge the support received from the Single Crystal CCD X-ray Diffractometer facility at IIT-Kanpur. V. C. is grateful to the DST for a J. C. Bose fellowship. P. K. thanks the University Grants Commission (UGC), India, for the Senior Research Fellowship. S. K. S. and P. P. S. acknowledge the Department of Science and Technology for the Start-up Research Grant (SRG/2020/001323). S. K. S. thanks IIT Hyderabad for generous seed grant funding. The support and resources provided by the PARAM Shivay Facility under the National Supercomputing Mission, Government of India at the Indian Institute of Technology, Varanasi, are gratefully acknowledged. F. P., J. F. G., and O. C. thank the European Research Council through the ERCCoG 725184 MULTIPROSMM (project no. 725184).

Uncontrolled Keywords:

Calculated values; Entropy changes; Ferro-magnetic interactions; Ferromagnetic interaction; Hydroxybenzylidene; Intramolecular antiferromagnetic interactions; Magnetic behavior; Maximum-entropy; Slow magnetic relaxations; Tetranuclear complexes

Subjects:

Chemistry

Divisions:

Department of Chemistry

Depositing User:

. LibTrainee 2021

Date Deposited:

29 Sep 2022 11:50

Last Modified:

29 Sep 2022 11:50

URI:

http://raiithold.iith.ac.in/id/eprint/10738