Syntheses, structures and properties of two one-dimensional coordination polymers constructed by phenol-sulfonate ligands and rare earth metal ions

Two new isomorphic and heterogeneous coordination polymers (CPs), namely {[RE (L) (H2O) 2] · (Hbipy) · H2O} n (RE = Yb(1), Y(2), Na2H2L = 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt, bipy = 2,2′-bipyridine) have been synthesized by hydrothermal methods and structurally characterized by elemental analyses, power X-ray diffraction (PXRD) and single crystal X-ray diffraction. Compounds 1 and 2 feature one-dimensional (1D) wavy ladder-like chain structures, which are further connected by hydrogen bonds from water molecules to result in two-dimensional (2D) layered structures. The 1H-protonated bipy molecules act as uncoordinated cations, leading to valences of zero in compounds 1 and 2. Compounds 1 and 2 emit luminescence at 382 nm and 372 nm in the ultraviolet regions, respectively. The luminescent emissions originate from the typical ligand-centered (n–π* and π–π*) transitions. In addition, compound 1 has characteristic near-infrared emission of ytterbium ion at 964 nm.