Dodecanuclear [Cu(II)6Gd(III)6] nanoclusters as magnetic refrigerants

A novel dodecanuclear complex, {(HL)(L)(DMF)Cu(II)Gd(III)(DMF)(H(2)O)}(6)]·6DMF (1; DMF = N,N-dimethylformamide), has been obtained using the ligand resulting from the condensation of 3-formylsalicylic acid with hydroxylamine (H(3)L). The exchange interaction between the phenoxo-bridged Cu(II) and Gd(III) ions is weak ferromagnetic (J = +1.01 cm(-1)). The combination of a high-spin ground state with small anisotropy leads to a significant magnetocaloric effect -ΔS(m)(0-7 T) = 23.5 J K g(-1) K(-1) at ～2 K].