Three-Dimensional Lanthanide Thiophenedicarboxylate Framework with an Unprecedented (4,5)-Connected Topology

Three novel three-dimensional metal−organic frameworks [Ln2(tdc)3(H2O)4]n, Ln = Dy(1), Ho(2), Er(3) (H2tdc = thiophene-2,5-dicarboxylic acid) have been synthesized and characterized by single crystal X-ray diffraction (XRD), powder XRD and IR spectra. X-ray crystallography reveals that the three complexes are isostructural and exhibit an unprecedented (4,5)-connected (42·64)(42·67·8) topology, in which the lanthanide ions act as unusual 5-connected nodes. The thermal stability and UV–vis absorption spectra of the title complexes have also been studied.