Three-dimensional pillared layered supramolecular networks comprising polymeric layers and tetrameric {H2O}4 pillars

Abstract

Three three-dimensional (3D) supramolecular lanthanide complexes, {[Ln₂(tdc)₃(H₂O)](H₂O)₂}_n (Ln = La 1, Ce 2, Pr 3; H₂tdc = 3,4-thiophenedicarboxylic acid), have been synthesized by hydrothermal reactions of H₂tdc and the corresponding lanthanide nitrate. Crystallographic data show that 1–3 are isomorphous and crystallize in the triclinic P space group. Each of them exhibits an interesting pillared layered supramolecular network comprising polymeric layers and up-up-down-down (uudd) cyclic tetrameric water pillars. Furthermore, in these compounds, tdc²⁻ anions unprecedentedly display three coordination modes in the polymeric layers. Elemental analyses (EA), infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA) were also employed, and the materials exhibit a reversible de- and rehydration behavior.