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 and 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 6K, whereas CC 3 shows outstanding magnetocaloric effect with entropy change of 34.6 J Kg-1 K-1 at 2K and ΔH=7T. The photoluminescent properties of CCs 1, 3 and 4 were also investigated, displaying intense characteristic emission spectra of EuIII, TbIII and DyIII ions.