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Eight novel coordination polymers, {[LnZn(2,3-pydc) 2 (ox) 0.5 (H 2 O) 3 ]·3H 2 O} n (Ln = Pr 1 , Nd 2 , Ho 3 , Er 4 , Yb 5 , Sm 6 , Eu 7 , Tb 8 ) (2,3-H 2 pydc = pyridine-2,3-dicarboxylic acid, H 2 ox = oxalic acid) are synthesized by the hydrothermal method and their structures are determined by single-crystal X-ray diffraction. They are isomorphous and crystallized in the triclinic system, with space group P 1 ¯ . In crystals, Ln(III) and Zn(II) ions are linked into 2D layers by 2,3-pydc 2− ligands adopting two coordination modes, and neighboring layers are bridged into 3D network structure through oxalate ligands in bridging tetradentate coordination mode. The IR, UV–Vis–NIR absorption spectra and emission spectra in the visible and near-infrared (NIR) region of polymers are determined and analyzed. All of polymers exhibit characteristic emission bands of corresponding Ln(III) ions, which should be attributed to sensitization from the d-block (Zn–ligand moiety) and ligands after introducing Zn(II) ion into the system of Ln(III) complexes. [ABSTRACT FROM AUTHOR]

Six Zn-Ln coordination complexes, [Nd 2 Zn 2 (C 6 H 5 COO) 10 (Imh) 2 (H 2 O) 2 ] ( 1 ), [Pr 2 Zn 2 (C 6 H 5 COO) 10 (Imh) 2 (H 2 O) 2 ] ( 2 ), [ErZn 2 (C 6 H 5 COO) 7 (Imh) 2 ] ( 3) , [HoZn 2 (C 6 H 5 COO) 7 (Imh) 2 ] ( 4 ), [EuZn 2 (C 6 H 5 COO) 7 (Imh) 2 ] ( 5 ), [TbZn 2 (C 6 H 5 COO) 7 (Imh) 2 ] ( 6 ) (C 6 H 5 COOH=benzoic acid, Imh=imidazole) have been synthesized under hydrothermal conditions and their crystal structures have been characterized by single crystal X-ray diffraction. All complexes are crystallized in triclinic system, with space group P ī. Complexes 1 and 2 are isomorphous with tetranuclear molecular structure and complexes 3–6 are isomorphous and trinuclear molecular complexes. All complexes are characterized by IR, UV–Vis–NIR and luminescent spectra in the visible and near-infrared (NIR) regions at room temperature. The study of luminescent properties indicates that all complexes exhibit the characteristic emission bands of corresponding Ln(III) ions, which should be attributed to sensitization from d-block and ligands after introducing Zn(II) ion and ligands into the system of Ln(III) complexes. Moreover, the NIR emission bands of complexes 1–4 exhibit shift and split, which can be evidenced in their UV–Vis–NIR absorption spectra. [ABSTRACT FROM AUTHOR]

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]