Three Gd-based magnetic refrigerant materials with high magnetic entropy: From di-nuclearity to hexa-nuclearity to octa-nuclearity.

Magnetocaloric effect (MCE) is one of the most promising features of molecular-based magnetic materials. We reported three Gd-based magnetic refrigerant materials, namely, Gd(L)(NO)(HO)‧CHCN‧HO (, HL = ()--[(1)-(2-hydroxy-3-methphenyl)methylidene]pyrazine-2-carbohydrazonic acid), {Gd(L)(CO)(CHOH)(HO)Cl}Cl‧4CHCN (), and Gd(L)(CO)(HO)‧2HO (3). Complex contains two Gd ions linked by two : : : : -L ligands, which are seven-coordinated in a capped trigonal prism, and complex possesses six Gd ions, contributing to a triangular prism configuration. For complex , eight Gd ions form a distorted cube arrangement. Moreover, the large values of magnetic entropy in the three complexes prove to be excellent candidates as cryogenic magnetic coolants.