First Examples of Polynuclear Lanthanide Diethylene Glycol Based Coordination Clusters.

Five lanthanide coordination clusters (CCs) [Ln7(µ3-OH)4(deg)2(Hdeg)2(ben)11]·xCH3CN [Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5); H2deg = diethylene glycol, Hben = benzoic acid; x = 7 for 1–4, x = 6 for 5], with diethylene glycol and benzoic acid as ligands, have been prepared and structurally characterized. All CCs consist of a heptanuclear lanthanide core with a scarce tip-sharing double-butterfly topology. Magnetic measurements revealed that CC 4 exhibits slow magnetic relaxation, with an energy barrier of about 6 K, whereas CC 3 shows outstanding magnetocaloric effects, with an entropy change of 34.6 J Kg–1 K–1 at 2 K and ΔH = 7 T. The photoluminescence properties of CCs 1, 3, and 4 were also investigated, displaying intense characteristic emission spectra of EuIII, TbIII, and DyIII ions. [ABSTRACT FROM AUTHOR]