Lanthanide coordination compounds with 2,2′-bipyridine-6,6′-dicarboxylate: Synthesis, crystal structure, luminescence and magnetic property

• Two types of eleven new lanthanide coordination compounds have been obtained.
• Na–Ln heterometallic coordination polymers are obtained at higher pH values.
• These compounds exhibit the characteristic emissions of lanthanide ions.
• Magnetic properties of the lanthanide compounds 1, 2, 3, 4 and 5 are investigated.

Two types of eleven new lanthanide coordination compounds, namely, {[Na2Ln2(bpdc)4(H2O)2]·3H2O}n, Ln = Gd (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), and [Ln(bpdc)(H2O)4][Ln(bpdc)2]·5H2O, Ln = Tb (7), Dy (8), Ho (9), Er (10), Yb (11) (H2bpdc = 2,2′-bipyridine-6,6′-dicarboxylic acid) have been synthesized under hydrothermal conditions. Compounds 1–6 formed at higher pH values (5.5–6.5) are isostructural 2D alkali–lanthanide heterometallic coordination polymers, which are simplified as a (3,3,4) network of {3·102}{3·4·5·102·11}{3·4·5}. Compounds 7–11 are obtained at lower pH values (pH = 2.0–3.0), and exhibit a discrete structure consisting of one complex cation and one complex anion, which are further extended into 2D metal–organic supramolecular frameworks by O−H⋯O hydrogen bonds. Additionally, the compounds exhibit the characteristic emissions of lanthanide ions in the visible and near-infrared region. Magnetic properties of compounds 1–5 have also been studied.

Compounds 1–6 are isostructural 2D alkali–lanthanide heterometallic coordination polymers and compounds 7–11 are isostructural discrete structures.Figure optionsDownload as PowerPoint slide