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, namely, {[Na(2)Ln(2)(bpdc)(4)(H2O)(2)]center dot 3H(2)O}(n), Ln = Gd (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), and [Ln(bpdc)(H2O)(4)][Ln(bpdc)(2)]center dot 5H(2)O, Ln = Tb (7), Dy (8), Ho (9), Er (10), Yb (11) (H(2)bpdc = 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 {3.10(2)}{3.4.5.10(2).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 center dot center dot center dot 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. (C) 2015 Elsevier B.V. All rights reserved.