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Six Zn/Cd metal–organic frameworks (MOFs), {[Zn2(dppa)(bpy)2(H2O)]·H2O}n (1), {[Zn2(dppa)(phen)2(H2O)]·3H2O}n (2), [Cd(H2dppa)(bpy)]n (3), {[Cd2(dppa)(dye)]·H2O}n (4), {[Cd4(dppa)2(H2O)9]·H2O}n (5) and {[Cd2(dppa)(bpe)2(H2O)]·H2O}n (6) (H4dppa = 5-(3′4′-dicarboxylphenoxy)isophthalic acid, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine, dye = 2,2′-dipyridylamine, bpe = 1,2-bis(4-pyridy) ethane), were synthesized and structurally characterized by elemental analyses, plasma (ICP) spectrometry, IR spectroscopy, and single-crystal X-ray diffraction analyses. 1–3 are 1D ring chains. 4 shows a 2D bilayer network based on a tetranuclear cadmium cluster linked by (dppa)4− ligands. 5 displays a 2D bilayer network based on a trinuclear cadmium cluster, in which (dppa)4− ion shows two different coordination modes. In contrast to the above MOFs, 6 possesses a 3D network structure based on dinuclear cadmium units cross-linked by (dppa)4− and bpe ligands. For 1–6, weak hydrogen bonding and π⋯π stacking contacts link the discrete 1D chains or 2D networks to form high-dimensional supramolecular structures. Especially, in 1–6, (dppa)4− ligand displays seven different coordination modes and conformations, which may show natural synergy in the structural diversity of the resulting MOFs. The remarkable characteristic of these frameworks is that 2 demonstrates highly selective and sensitive bifunctional luminescent sensing towards acetone and Fe3+ ion. In addition, the thermal stabilities and luminescence properties of the MOFs were studied. [ABSTRACT FROM AUTHOR]

A series of Ln-sulfoterephthalate coordiantion polymers, namely, [Ln(2-stp)(4,4'-bbpi) (H2O)2]⋅H2O [Ln = Eu (1), Tb (2), Dy (3)] (2-H3stp = 2-sulfoterephthalate; 4,4'-bbpi = 4,4'-bisbiphenylimidazole), were prepared by hydrothermal method and characterizatied by EA, IR, TGA, and PXRD technologies. Single crystal X-ray diffraction analyses show that the three complexes are isostructral twodimensional network featuring helical chain structures. The fluorescence studies show that the emissions of the coordination polymers exhibit the characteristic peaks of lanthanide ions, which means they could be potential fluorescence materials. [ABSTRACT FROM AUTHOR]

Two coordination polymers, {[Zn2(L)(bpy)] ·2H2O} n ( 1) and [Zn2(L)(bpe)] n ( 2) [H4L = terphenyl-2,2′,4,4′-tetracarboxylic acid, bpy = 4,4′-bipyridine, and bpe = 1,2-bis(4-pyridyl)ethane], were hydrothermally synthesized under similar conditions and characterized by elemental analysis, IR spectroscopy, TGA, and single-crystal X-ray diffraction analysis. Compound 1 has a 3D framework containing Zn-O-C-O-Zn 1D chains. Compound 2 exhibits a 3D framework, which features tubular channels. The channels are occupied by bpe molecules. The differences in the structures demonstrate that the auxiliary dipyridyl-containing ligand has a significant effect on the construction of the final framework. Additionally, the fluorescent properties of the two compounds were also studied in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

Two new coordination polymers, [Zn(H2btc)(4,4'-bpy)2]n (1) and {[Cd(H2btc) (terpy)] · H2O}n (2) (H4btc = biphenyl-2,2',4,4'-tetracarboxylic acid, 4,4'-bpy = 4,4'-bipyridine, terpy = terpyridine), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. Complexes 1 and 2 are 1-D chains linked through partially deprotonated H4btc. The adjacent 1-D chains of 1 are further formed into 2-D supramolecular architecture through inter-chain N-H···O hydrogen bonds. In contrast, due to a different auxiliary ligand, the 1-D chains of 2 are further extended into 3-D supramolecular framework through inter-chain O-H···O hydrogen bonds. Thermal stabilities and luminescence of 1 and 2 were also studied. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two series of Pb substituted α-Bi 1-x Pb x Pd and β-Bi 2-x Pb x Pd were successfully synthesized by facile solid-state method. • Bi 1-x Pb x Pd (0 ≤ x ≤ 0.2) and Bi 2-x Pb x Pd (0 ≤ x ≤ 0.5) samples show bulk superconductivity and T c monotonically change as increases of Pb content. • One can see that the cell volume has also shown a monotonous decreasing change with higher Pb content for both alloys, which can be attributed to the slightly smaller atomic radius of Pb (1.75 Å) than Bi (1.82 Å). Abstract A series of Pb-doped Bi-based alloys, α-Bi 1-x Pb x Pd (0 ≤ x ≤ 0.5) and β-Bi 2-x Pb x Pd (0 ≤ x ≤ 0.6), were synthesized by facile solid-state reaction method. The powder X-ray diffraction confirmed that the crystal structure of samples remained the same after Pb-doping and the cell volume decreased with increasing Pb content. The influence of Pb-doping effect on superconductivity of BiPd and Bi 2 Pd alloys has been systematically examined by the magnetic susceptibility and resistivity measurements. Both alloy systems have shown bulk superconductivity and metallic conductivity in normal state. Furthermore, the superconducting onset temperature (T c) gradually decreased with higher Pb content for both systems. The T c dropped from 3.7 K for BiPd to 2.7 K for Bi 0.8 Pb 0.2 Pd, whereas the T c dropped from 5.3 K for Bi 2 Pd to 2.4 K for Bi 1.5 Pb 0.5 Pd. [ABSTRACT FROM AUTHOR]