1. Three Series of 3d–4f Heterometallic PolymersBased on [LnCu6] or [Ln6Cu24] Clustersand Formate Bridges: Displaying Significant Magnetocaloric Effect.
- Author
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Li, Zhong-Yi, Wang, Yu-Xian, Zhu, Jiang, Liu, Shu-Qin, Xin, Gang, Zhang, Jian-Jun, Huang, He-Qing, and Duan, Chun-Ying
- Subjects
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MAGNETOCALORIC effects , *CHEMICAL synthesis , *CRYSTAL structure , *HYDROGEN-ion concentration , *MICROCLUSTERS , *POLYMERS - Abstract
The syntheses, structures,and characterization of three seriesof one-dimensional (1D) and three-dimensional (3D) 3d–4f cluster-basedpolymers with AA (HGly or HAla) and formate as mixed ligands are described.Under the pH values of 6.0 and 5.2, respectively, three 1D undulatingchains [Ln = Gd, (1); Tb, (2); and Dy(3)] and two 3D frameworks [Ln = Gd, (4) and Tb,(5)] with a 3-connected pcu-hnetworkwere obtained. Both of them use Gly-based heptanuclear trigonal prism[LnCu6] clusters and mononuclear Ln3+as nodeslinked by syn–anti formate ligands. Moreover, three 3D polymers[Ln = Gd, (6); Tb, (7); and Dy (8)] with a 6-connected pcunetwork were built fromAla-based [Ln6Cu24] clusters and formate bridges.The formate ligand played an important role not only for the constructionof the cluster units but also for their further linkage to extendedarrays. Magnetic analyses indicate the three Gd3+-containingcompounds bear an interesting magnetocaloric effect, and the −ΔSm(T) values are 5.8, 6.0, and 18.8 J kg1–K–1(ΔH= 5 T) for 1, 4, and 6, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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