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Experimental and theoretical investigations on three DyIII4 single molecule magnets: structural and magneto-structural correlations

Mandal S, Pramanik A, Dey S, Carrella LM, Rajaraman G, Rentschler E, Mohanta S (2022)

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Publication Type: Journal article

Publication year: 2022

Journal

Book Volume: 51

Pages Range: 14753-14766

Journal Issue: 38

DOI: 10.1039/d2dt02348b

Abstract

The work in this report describes the syntheses, crystal structures, dc/ac magnetic behaviour, and theoretical calculations (both ab initio CASSCF and DFT) of three defect dicubane/planar butterfly type tetradysprosium(iii) compounds of compositions [Dy^III4L4(μ3-OH)2(carboxylate)2(dmf)2] (carboxylate = formate (1), acetate (2), propionate (3)), where H2L = 2-(2-hydroxy-3-ethoxybenzylideneamino)phenol. In the butterfly type structures, two Dy^III centres (Dyb) occupy the body positions while two other (Dyw) units occupy the wing positions. SHAPE analyses reveal that the coordination geometries of the Dyb and Dyw centres, both octacoordinated, are triangular dodecahedron (TDD) and square antiprism (SAPR), respectively. Variable-temperature magnetic susceptibility measurements give an indication of weak antiferromagnetic interactions and variable-field magnetization measurements reveal strong anisotropy in all the three compounds. The variable-temperature/frequency in-phase/out-of-phase AC susceptibility data reveal that all these three compounds are SMMs with two relaxation channels under zero dc field; slow relaxation (SR) and fast relaxation (FR) processes could be assigned to the SAPR (Dyw) and TDD (Dyb) metal centres, respectively. The simulated Ueff and τ0 values are: 49.0 cm⁻¹ and 1.76 × 10^-7 s for 1, 30.3 cm⁻¹ and 1.51 × 10^-8 s for 2 and 23.4 cm⁻¹ and 9.64 × 10^-7 s for 3. Furthermore, ab initio CASSCF/RASSI-SO/SINGLE_ANISO calculations reveal that the ground state of Dy^III centres are axial in nature with a dominating contribution from mJ = |±15/2>. The magnetization relaxation occurs via the first excited KD resulting in the large computed blocking barrier of Dyw (SAPR) centres compared to that of the Dyb (TDD) centres which corroborates the experimental measurements. The exchange parameters obtained from DFT calculations are generally in line with those obtained from the fitting of χMT vs. T in POLY_ANISO calculations. Interesting structural and magneto-structural correlations have been found, which are the major outcomes of this investigation.

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How to cite

APA:

Mandal, S., Pramanik, A., Dey, S., Carrella, L.M., Rajaraman, G., Rentschler, E., & Mohanta, S. (2022). Experimental and theoretical investigations on three DyIII4 single molecule magnets: structural and magneto-structural correlations. Dalton Transactions, 51(38), 14753-14766. https://dx.doi.org/10.1039/d2dt02348b

MLA:

Mandal, Shuvankar, et al. "Experimental and theoretical investigations on three DyIII4 single molecule magnets: structural and magneto-structural correlations." Dalton Transactions 51.38 (2022): 14753-14766.

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