Construction of a High Nuclear Gadolinium Cluster with Enhanced Magnetocaloric Effect through Structural Transition

[Image: see text] Starting from a dinuclear complex {Gd(2)(L)(2)(NO(3))(4)(H(2)O)(2)}·2(CH(3)CN) (1) based on 2,6-dimethoxyphenol (HL), a nonanuclear cluster {Gd(9)(L)(4)(μ(4)-OH)(2)(μ(3)-OH)(8)(μ(2)-OCH(3))(4)(NO(3))(8) (H(2)O)(8)}(OH)·2H(2)O (2) was obtained via modulating the amount of the ligand and base. Both of them have been structurally and magnetically characterized. Complex 1 decorates the Gd(2) core bridged by double μ(2)-phenoxyl oxygen atoms and coordinated neutral CH(3)CN molecules, while 2 features the Gd(9) core with a sandglass-like topology. Magnetic investigations reveal that the weaker antiferromagnetic interactions between adjacent metal ions exist in complex 2 than in 1, which is in agreement with the theoretical results. Meanwhile, the magnetocaloric effect with a maximum −ΔS(m) value changes from 27.32 to 40.60 J kg(–1) K(–1) at 2 K and 7 T.