Incorporating metal clusters into three-dimensional Ln(III)-Cu(I) coordination frameworks through linear ligands

By using linear multifunctional ligands with different geometries, three novel three-dimensional (3D) Ln-M heterometallic coordination polymers, [Nd(HO)(CuI)]·HO (1) (Hnic = nicotinic acid) and [LnCu(inic)(ox)]·HO [Ln = Nd (2), Eu (3); Hinic = isonicotinic acid, Hox = oxalic acid], have been synthesized under hydrothermal conditions. Compound 1 exhibits a novel 3D coordination framework constructed by CuI clusters, Nd centers, and nic ligands. Our present work represents the first example of 3D Ln-M heterometallic coordination framework incorporating discrete cubane transition metal clusters covalently bonded to lanthanide centers through linear ligands. An unusual chemical rearrangement from Hinic to ox occurs in the formation of 2 and 3. Compounds 2 and 3 are isostructural and possess the first 3D coordination framework based on the linkage of two-dimensional layers constructed by tetranuclear LnCu clusters and inic ligands. Furthermore, the luminescent properties of 3 were studied. © 2007 American Chemical Society.