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One luminescent Cd2+ coordination polymer, {[Cd(tbca)(H2O)]}n (1) (Htbca = 4'-(1H-tetrazol-5-yl)-biphenyl-4-carboxylic acid), has been synthesized and characterized by infrared spectroscopy and powder X-ray diffraction. Structural analysis revealed that 1 was a 3D framework with a 3,6-connected rtl topology. Fluorescence titration experiments demonstrated that 1 was an excellent multi-functional probe for metal ions and amino acids. [ABSTRACT FROM AUTHOR]

A new 3-position substituted imidazo[1,2-a]pyridine ligand, 4-(2-chloroimidazo[1,2-a] pyridine-3-carboxamido)phthalic acid (H2L), was conveniently synthesized and acts as a three-connecting T-shaped building block. Based on this ligand, two isostructural coordination polymers, [ML(H2O)]n (M = Zn (1) and Co (2)) with a rare one-dimensional (1D) ladder-like chain structure, were solvothermally synthesized and structurally characterized. There exist hydrogen bond and lone-pair–π interactions between two adjacent ladder chains. Compared to the H2L ligand, coordination polymer 1 reveals a blue-shifted emission stemming from ligand-to-metal charge transfer, meanwhile, coordination polymer 2 presents a dominant antiferromagnetism. Interestingly, the carboxylate anion (COO−) in coordination polymers 1 and 2 could be protonated into carboxylic acid (–COOH), upon exposure to HCl vapor. As a result, coordination polymers 1 and 2 display reversible luminescent switching in the response to acid-base vapor stimuli, which mainly originates from the conversion between lone-pair–π and cation–π interactions mediated by the protonation-deprotonation processes. Such stimulus-responsive conversion between lone-pair–π and cation–π interactions is first reported in coordination polymers, and provides a promising approach to design and construct smart coordination polymer materials. [ABSTRACT FROM AUTHOR]

Second-sphere coordination refers to any intermolecular interactions with the ligands directly bound to the primary coordination sphere of a metal ion. Four supramolecular complexes, 0.5[L·2H]2+·0.5[MCl4]2−·[CH3OH]·0.5[CH2Cl2] (M = Co, crystal1; M = Mn, crystal2), 0.5[L·2H]2+·0.5[ZnBr4]2−·[CH3OH]·0.5[CH2Cl2] (crystal3), and 0.5[L·2H]2+·0.5[Cu2Br4]2−·H2O (crystal4), based on naphthalene-based ligand N,N,N′,N′-tetra-p-methylnaphthyl-ethanediamine (L), have been synthesized. X-ray analysis reveals that1–3are isostructural, in which the methanol molecules are bridges, connecting the protonatedLand metal chloride anions via N–H⋯O and O–H⋯Cl (Br) interactions to construct the host framework, and forming X-shaped cavity accessible for the inclusion of weakly polar guest molecules of dichloromethane. Dichloromethane is connected with the host framework through van der Waals forces. In4, a dinuclear anion [Cu2Br4]2−is connected with the ligand through N–H⋯Br interactions, in which the water molecules are accommodated between chains formed by the ligand and [Cu2Br4]2−. Structure stability, thermal analysis, and photoluminescent properties were studied for1–4. X-shaped host framework formed by second-sphere coordination strategy. [ABSTRACT FROM AUTHOR]

A polyoxomolybdate, [Cu2(pz)(Mo3O10)] n (pz = pyrazine) (1), has been synthesized hydrothermally and characterized by elemental analysis, IR, X-ray photoelectron spectra, and thermogravimetric analysis. Single-crystal X-ray diffraction demonstrates that 1 has a 3-D architecture constructed by combination of {Mo3O10} units and [Cu2(pz)]2+. All the terminal oxygen atoms of the polyoxomolybdate are coordinated by univalent copper. Pyrazine came from in situ decarboxylation of 2-pyrazinecarboxylic acid and Cu+ from the in situ reduction of Cu2+ during the hydrothermal synthesis. [ABSTRACT FROM PUBLISHER]

A polyoxoniobate, [Cu(en)2]4{[Nb6O19H2]K(H2O)5}2 ⋅ (H2en) ⋅ 17H2O (en = ethylenediamine) (1), has been synthesized and characterized by elemental analysis, IR, XPS, TGA, and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P1, with a = 12.3533(16) Å, b = 12.7188(16) Å, c = 29.626(4) Å, α = 93.235(2)°, β = 96.094(1)°, γ = 106.098(2)°, V = 4429.0(10) Å3, Z = 2. The polyoxoanion is composed of a Lindqvist-type [Nb6O19H2]6- dimer bi-bridged via two K+. K+ is 10-coordinate with 10 oxygens, three from one [Nb6O19H2]6-, one from a terminal oxygen of another [Nb6O19H2]6- moiety, and the other six from water molecule. Adjacent dimeric polyoxoanions are linked to form an infinite 1-D chain via O-H ··· O hydrogen-bonding interactions which exist between the two water trimers and the dimeric polyoxoanions. [ABSTRACT FROM AUTHOR]

The reaction of 1,3-bis(pyridyl-4-ylthio)propan-2-one with Cu(ClO4)2 · 6H2O gave a new complex {[Cu2(4PDS)2(ox)(H2O)4](ClO4)2}n (4PDS = 4,4'-dipyridyldisulfide, ox = oxalate), with 4PDS and ox being created by the Cu(II)-assisted oxidation of 1,3-bis(pyridyl-4-ylthio)propan-2-one. The complex determined by X-ray crystallography is a 1D polymer, in which metallacycles formed by two 4PDS and two Cu(II) ions are further bridged through ox anions. It crystallizes in the orthorhombic system, space group Fddd, with lattice parameters a = 15.106(2), b = 23.667(4), c = 27.637(3) Å and Z = 8. [ABSTRACT FROM AUTHOR]