Crystal structure of the dodecanuclear coordination compounds [RE12(DMF)24(HCOO)8(OH)16]I3·4DMF (RE = Eu, Nd).

By slow hydrolysis of solutions of [Eu(DMF)8]I3 or [Nd(DMF)8]I3 in dimethylformamide (DMF), single crystals of the coordination compounds [ RE 12(DMF)24 (HCOO)8(OH)16]I3·4DMF (RE = Eu, Nd) were obtained. Both compounds crystallise isotypically in a tetragonal structure with space group I 422 (No. 97, Z = 2, a = 21.881(3), 21.6340(10) and c = 20.873(2), 21.0612(9) Å for Nd and Eu compounds, respectively). The crystal structure shows a [ RE 12O56] core unit with O atoms from formate and hydroxide anions μ3-bridging the metal centres. The dodecanuclear cationic units are arranged in a body-centred packing topology, surrounded by iodide anions in a β cage pattern. Rietveld refinement confirmed the structure model, and the presence of hydroxide anions was shown by FT-IR spectroscopy. Susceptibility measurements on the Nd compound showed paramagnetic behaviour and a temperature dependence of μ eff typical for trivalent Nd cations. Two dodecanuclear coordination compounds of trivalent rare earth metal cations show short interatomic RE–RE distances due to bridging O atoms from hydroxide and formate anions. Magnetic susceptibility and structural details suggest single molecule magnetic behaviour. [ABSTRACT FROM AUTHOR]