A Series of Lanthanide Compounds Constructed from Ln8 Rings Exhibiting Large Magnetocaloric Effect and Interesting Luminescence

A series of lanthanide compounds, [Ln8(CH2OHCH2OH)8(SO4)12]·m(C2H7N)·nH2O (Ln = Gd (1), Sm (2), Tb (3), La (5), m = 2, n = 2; Ln = Eu (4), m = 0, n = 8), which contain Ln8 rings by sulfate and glycol as the ligand have been synthesized and characterized. Besides, small organic amine and l-tartaric acid act as dual templating roles during the synthetic process. Magnetic investigation of compound 1 reveals the existence of weak antiferromagnetic interactions between GdIII ions and the data of magnetic entropy change (−ΔSm) is 36.86 J K–1 kg–1 (108.55 mJ cm–3 K–1) for ΔH = 7 T at 2.0 K, which is comparatively large among GdIII based compounds. Additionally, because of the excellent luminescence properties of SmIII, TbIII, and EuIII, compounds 2–4 were investigated.