A Series Three-Dimensional Ln4Cr4 (Ln = Gd, Tb, Er) Heterometallic Cluster-Based Coordination Polymers Containing Interesting Nanotubes Exhibiting High Magnetic Entropy
journal contributionposted on 31.03.2020, 17:06 by Yanzhao Yu, Xingxiang Pan, Chenhui Cui, Ximing Luo, Ningfang Li, Hua Mei, Yan Xu
A series of novel 3D 3d-4f heterometallic cluster-based coordination polymers, [Ln4Cr4(μ3-O)4(μ4-O)4(NA)8(H2O)12]·xH2O (Ln = 1-Gd, 2-Tb, 3-Er; HNA = nicotinic acid; x = 13 (1-Gd), 11.33 (2-Tb), 15 (3-Er)), have been successfully synthesized by hydrothermal method using nicotinic acid as bridging ligand. The single-crystal X-ray diffraction (SCXRD) analysis indicated that the basic unit of Ln4Cr4 shows a butterfly-shaped structure. Furthermore, each Ln4Cr4 cluster connects with other four Ln4Cr4 clusters by bridging NA– ligands to form a 3D structure containing interesting 1D honeycomb-shaped coordination nanotubes. The variable temperature magnetic susceptibility measurements of compound 1 revealed that the existence of antiferromagnetic (AF) coupling between the metal ions in the Gd4Cr4 clusters. Field-dependent isothermal magnetization studies displayed that the magnetic entropy change (−ΔSm) value of 1-Gd reached 22.05 J K–1 kg–1.
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single-crystal X-ray diffractionLn 4 Cr 4-4f heterometallic cluster-based coordination polymersnicotinic acidHeterometallic Cluster-Based Coordination Polymers ContainingLn 4 Cr 4 clusterErHNA1 D honeycomb-shaped coordination nanotubesNAH 2 Onovel 3 D 3Nanotubes Exhibiting HighSeries Three-Dimensional Ln 4 Cr 41- GdGd 4 Cr 4 clustersSCXRDTbAFLn 4 Cr 4 clusters3 D structure