Magnetocaloric effect in a high-spin ferromagnetic molecular cluster.

The reaction of MnCl·4HO with HL ((1-methyl-1H-imidazol-2-yl)methanol) and pdH (1, 3 propanediol) in a basic MeCN solution results in the formation of a mixed-valence [Mn] cationic cluster and two [MnCl] counter anions. The metallic skeleton of the cluster describes two geometrically equivalent mixed-valent, linked [Mn Mn ] 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 = 22 spin ground state for the [Mn Mn ] supertetrahedra, which are pair-linked by a weak antiferromagnetic coupling.