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Seven coordination polymers having the general formula {[Ln2(2,6-pydc)(ox)2⋅(H2O)4]⋅3H2O}n (Ln = Sm 1, Eu 2, Gd 3, Tb 4, Dy 5, Ho 6, Er 7; 2,6-pydc2− = 2,6-pyridinedicarboxylate, ox2− = oxalate) were synthesized by the hydrothermal method. Their IR, UV-Vis-NIR absorption spectra, and Vis-NIR emission spectra were investigated, and the luminescent properties of the polymers were studied in detail. Crystal structures were determined by means of a single-crystal X-ray diffractometer, and all of them proved to have three-dimensional frameworks. Except for polymers 3 and 7, the polymers displayed the characteristic emissions of Ln(III) ions due to the effective sensitization of ligands. At the same time, the 4f orbitals of Ln(III) ions were shifted by the effects of ligand field, which influenced emission spectra and absorption spectra of some of the polymers. [ABSTRACT FROM AUTHOR]

Abstract: Using aromatic carboxylic acids as main ligands, four Ln(III) coordination polymers, [Er(CH3C6H4COO)2(Ac)(H2O)] n (1), [Yb(β-C10H7COO)2(Ac)(H2O)] n (2), [Nd(C9H7O2)3] n (3) and [Ho(C9H7O2)3] n (4) (CH3C6H4COO= p-toluylate, Ac=acetate, β-C10H7COO= β-naphthoyloxy, C9H7O2 =cinnamate), were synthesized by hydrothermal method and their structures were studied by single-crystal X-ray diffraction. Polymers 1 and 2 possess 2D layer structures, and polymers 3 and 4 possess 1D chain structures. At room temperature in the solid state, the IR, UV–Vis–NIR spectra and the emission spectra in the visible and near-infrared (NIR) regions of the four polymers were determined. In the NIR region, polymers 1–4 show characteristic emission bands of the corresponding Ln(III) ions which exhibit shift, splitting or broadness in comparison with their theoretical emission bands. This can be confirmed by their UV–Vis–NIR spectra and discussed emphatically. [Copyright &y& Elsevier]

Four new lanthanide(Ш) coordination polymers, [Ln( p-aminobenzoate)(DMF)(HCOO) (HO)] (Ln = Sm 1, Tb 2, Pr 3) and {[Pr(2,5-dcp)(CHCOO)(HO)]·1.5HO} ( 4) (DMF = N, N-dimethylformamide, 2,5-dcp = pyridine-2,5-dicarboxylate), have been synthesized by hydrothermal method. The structures are determined by the single-crystal X-ray diffraction. The four polymers all crystallize in the monoclinic space group P2/n. Polymers 1 and 2 are isostructural; both Sm ion of polymer 1 and Tb ion of polymer 2 are eight-coordinate. Although polymer 3 possesses the same asymmetric unit as polymers 1 and 2, the three are not isomorphous. The Pr ions in polymers 3 and 4 are nine-coordinate. In polymers 1, 2 and 3 the neighboring units are bridged by formyloxy and extend into infinite chains, which are connected by hydrogen bonds to form a hydrogen bond network. However, polymer 4 is bridged by pyridine-2,5-dicarboxylate and acetates to form an infinite 3D network. At room temperature, the IR, UV-Vis-NIR and emission spectra of the four polymers were measured and analyzed. The four polymers emit in the visible or NIR region. The luminescent properties are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Six novel heterometallic Zn–Ln coordination polymers {[ZnLnCl(pydc)2(H2O)6]·3H2O} n (Ln=Nd 1, Pr 2, Sm 3, Eu 4, Tb 5, Dy 6; pydc=pyridine-2,5-dicarboxylate) were synthesized by the hydrothermal method, and their structures were measured by the single-crystal X-ray diffraction. The IR and UV–Vis–NIR absorption spectra, and the luminescence spectra in the visible and near-infrared (NIR) regions of the six complexes were determined at room temperature. They possess the same crystal structure, and the Zn(II) and Ln(III) ions in each complex are bridged into 1D infinite chain by pyridine-2,5-dicarboxylates. Meanwhile, there are numerous hydrogen bonds which result in the 3D hydrogen bonding network in the crystal. In the visible and NIR regions, the emission spectra of the complexes show the characteristic bands of the corresponding Ln(III) ions, which are mainly attributed to the sensitization from the d-L-moiety to f-L-moiety after forming the Zn–Ln complexes. In this paper, we first report the Zn–Sm complex which can exhibit the emission bands of Sm(III) in the NIR region, and discuss the sensitization from the d-L-moiety to f-L-moiety on the basis of the different characteristics of levels for different Ln(III) ions. [Copyright &y& Elsevier]

Fourteen Ni/Co-Ln heterometallic coordination polymers were successfully synthesized. All CPs are bridged into the 3D network structure by 2,3-pydc2- and ox2- and exhibit characteristic emission bands of the corresponding Ln(III) ion. [Display omitted] • A series of heterometallic NiII/CoII-LnIII coordination polymers have been synthesized by using pyridine-2,3-dicarboxylic acid as main ligand. • They exhibit characteristic luminescence of Ln(III) ions. • NIR emission bands of Ln(III) ions in some polymers present shift, split and broad under the double influence from the crystal field and Ni(II) or Co(II) ions. Fourteen isomorphic heterometallic coordination polymers (CPs) with general formulas of {[LnM(2,3-pydc) 2 (ox) 0.5 (H 2 O) 3 ]·3H 2 O} n (M = Ni, Ln = Pr 1 , Nd 2 , Sm 3 , Eu 4 , Gd 5 , Tb 6 , Dy 7 ; M = Co, Ln = Pr 8 , Nd 9 , Sm 10 , Eu 11 , Gd 12 , Tb 13 , Dy 14 ; 2,3-pydc2– = fully deprotonated pyridine-2,3-dicarboxylic acid, ox2– = fully deprotonated oxalic acid) have been synthesized by hydrothermal methods. All the CPs crystallize in triclinic P -1 space group and exhibit a 3D network formed by 2,3-pydc2– and ox2– bridging Ln(III) and Ni(II)/Co(II) ions. Meamwhile the room temperature photoluminescent properties have been explored. Except for CPs 5 and 12 , the other CPs exhibit characteristic luminescence of Ln(III) ions. [ABSTRACT FROM AUTHOR]