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 2 (L)(NO 3 )(H 2 O)‧CH 3 CN‧H 2 O ( 1 , H 2 L = ( Z )- N -[(1 E )-(2-hydroxy-3-methphenyl)methylidene]pyrazine-2-carbohydrazonic acid), {Gd 6 (L) 6 (CO 3 ) 2 (CH 3 OH) 2 (H 2 O) 3 Cl}Cl‧4CH 3 CN ( 2 ), and Gd 8 (L) 8 (CO 3 ) 4 (H 2 O) 8 ‧2H 2 O (3). Complex 1 contains two Gd III ions linked by two η 2 : η 1 : η 1 : η 1 : μ 2 -L 2- ligands, which are seven-coordinated in a capped trigonal prism, and complex 2 possesses six Gd III ions, contributing to a triangular prism configuration. For complex 3 , eight Gd III 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.