Syntheses, Structures and Properties of Lanthanide Coordination Polymers Constructed from Mixed Acid

Two new coordination polymers, [Ln(oba)(ox)(0.5)(H2O)(2)](n) (Ln = Ho (1), Eu (2); H(2)oba = 4,4'-oxybis(benzoic acid), H(2)ox = oxalic acid) have been synthesized under hydrothermal conditions. According to single-crystal X-ray diffraction analyses, complex 1 crystallizes in the monoclinic system, space group P2(1)/c with a = 13.783(2), b =10.0120(15), c = 12.1974(18) angstrom, beta = 105.217(2)degrees, V = 1624.2(4) angstrom(3), C15H12O9Ho, M-r = 501.18, Z = 4, D-c = 2.050 g/cm(3), F(000) = 964, mu = 4.919 mm(-1), lambda(MoK alpha) = 0.71073 angstrom, GOOF = 1.124, the final R = 0.0239 and wR = 0.0570 for 3310 independent reflections with R-int = 0.0298. Complexes 2 and 1 are isostructural. Oba and ox ligands bridge the Ln(III) ions into 2D layers with (4,4) topology, which are further interlinked into a 3D supramolecular network by hydrogen bonds. TG curves of the two complexes are studied to examine their thermal stabilities. Additionally, complex 2 shows red fluorescence in the solid state at room temperature.