Magnetocaloric effect in a high-spin ferromagnetic molecular cluster.

The reaction of MnCl ₂ ·4H ₂ O with HL ((1-methyl-1H-imidazol-2-yl)methanol) and pdH ₂ (1, 3 propanediol) in a basic MeCN solution results in the formation of a mixed-valence [Mn ₂₀ ] cationic cluster and two [Mn ^II Cl ₄ ] counter anions. The metallic skeleton of the cluster describes two geometrically equivalent mixed-valent, linked [Mn ^III ₆ Mn ^II ₄ ] supertetrahedra in which nearest-neighbor metal ions have a different oxidation state. Magnetic susceptibility, magnetization data and heat capacity measurements support evidence of predominant ferromagnetic correlations, leading to a s = 22 spin ground state for the [Mn ^III ₆ Mn ^II ₄ ] supertetrahedra, which are pair-linked by a weak antiferromagnetic coupling. The properties are discussed in the context of the magnetocaloric effect and the potential application of this compound in cryogenic refrigeration.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2024 Agapaki, Charkiolakis, Nichol, Gracia, Evangelisti and Brechin.)