MoO 4 2- -templated Ln 20 Ni 21 heterometallic clusters with large low-field magnetic entropy.

The anionic template method is an effective strategy for synthesizing high-nuclearity transition-lanthanide (3d-4f) heterometallic clusters. Herein, two lanthanide clusters with formulas [Gd 20 Ni 21 (μ 3 -OH) 21 (CO 3 ) 6 (IDA) 21 (C 2 H 4 NO 2 ) 6 (C 2 O 4 ) 3 (MoO 4 ) 1.5 (μ 2 -OH) 1.5 (H 2 O) 9 ]Cl 10.5 ·79H 2 O (1) and [Tb 20 Ni 21 (μ 3 -OH) 21 (CO 3 ) 6 (IDA) 21 (C 2 H 4 NO 2 ) 6 (C 2 O 4 ) 3 (MoO 4 )(μ 2 -OH) 2 (H 2 O) 10 ]Cl 11 ·32H 2 O (2) were synthesized by introducing MoO 4 2- anions as templates. Structural analysis indicates that compounds 1 and 2 are isomorphic, featuring a fascinating triangular-shaped metal framework. Magnetic property investigations illuminate the fact that compound 1 exhibits a large -Δ S m of 37.83 J kg -1 K -1 at 3 K for Δ H = 7 T. In particular, it is worth mentioning that compound 1 has an excellent low-field magnetic entropy (-Δ S m = 23.85 J kg -1 K -1 at 2 K, 2 T).