Co3Gd4 Cage as Magnetic Refrigerant and Co3Dy3 Cage Showing Slow Relaxation of Magnetisation

Two structurally dissimilar 3d-4f cages having the formulae [(Co-III)(3)Gd-4(mu(3)-OH)(2)(CO3) ((O2CBu)-Bu-t)(11)(teaH)(3)]center dot 5H(2)O (1) and [(Co-III)(3)Dy-3(mu(3)-OH)(4)((O2CBu)-Bu-t)(6)(teaH)(3)]center dot(NO3)(2)center dot H2O (2) have been isolated under similar reaction conditions and stoichiometry of the reactants. The most important factor for structural diversity seems to be the incorporation of one mu(3)-carbonate anion in 1 and not in 2. Co atoms are in a +3 oxidation state in both complexes, as shown by the Bond Valence Sum (BVS) calculations and bond lengths, and as further supported by magnetic measurements. Co3Gd4 displays a significant magnetocaloric effect (- increment S-m = 25.67 J kg(-1) K-1), and Co3Dy3 shows a single molecule magnet (SMM) behavior.

Automated summary

Two structurally dissimilar 3d-4f cages were isolated under similar reaction conditions, with Co3Gd4 exhibiting a significant magnetocaloric effect and Co3Dy3 showing single molecule magnet behavior. The incorporation of a μ3-carbonate anion seems to be the main factor for the structural diversity between the two complexes.