Construction of a 2D Cd(Ⅱ) Network with Homohelical Chains Based on 1,3-Dipyridyl Benzene(Dpb) and 4,4'-Sulfonyldibenzoic Acid(H_2sdb)

A two-dimensional（2D） coordination polymer {[Cd2（sdb）2（dpb）2]·3H2O}n（1） was prepared by solvothermal reaction of two types of V-shaped ligands： 1,3-dipyridyl benzene（dpb） and deprotonated 4,4＇-sulfonyldibenzoic acid（H2sdb）. It was characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Complex 1 crystallizes in the monoclinic system, space group Fdd2 with a = 46.247（10）, b = 9.994（2）, c = 24.267（6） A, V = 11216（4） A3, C60H46Cd2N4O15S2, Mr = 1387.97, Dc = 1.559 g/cm^3, F（000） = 5296.0, μ = 0.902 mm^-1 and Z = 8. Each [Cd（COO）]2 cluster links four sdb2- anions to form infinitely ABAB stacked 2D wave-like sheets, in which each sheet contains the same helical chains, and the helical directions of sheets A and B are reversed. Dpb links the rest coordinated sites of [（COO）Cd]2 cluster to form a 2D network. In addition, the solid fluorescence of 1 and dpb is also studied.

Crystal Structures and Photoluminescence Properties of Two Lanthanide Complexes Constructed by Flexible 1,2-Phenylenediacetic Ligand

Two 3D Ln-organic coordination frameworks（Ln = Pr3＋ for 1 and Er3＋ for 2） have been constructed. Single-crystal X-ray diffraction analysis reveals that the two complexes have similar structures and belong to the monoclinic C2/c space group. The trans-μ4-（η2：η1）-（η1：η1） 1,2-pda2- anions link the LnIII centers to generate a 2D network containing helical motif. The dimensionality is extended into a 3D architecture through cis-bis（μ2-η2：η1） 1,2-pda2- anions linking. The geometry of Ln3＋ ions is single-capped anti-square prism. Two complexes were characterized by IR spectra and thermogravimetric analysis. The solid fluorescence of 1 and 2 was also investigated at room temperature.

A New Cadmium(Ⅱ) Coordination Polymer Extended through Hydrogen Bonds and π-π Stacking Interactions: Synthesis and Photoluminescence Property

A new coordination polymer, {[Cd(OPY)(tdc)(HO)]·H2 O}n(OPY = 4,4?-(oxybis(4,1-phenylene))dipyridine, H2 tdc = thiophene-2,5-dicarboxylic acid), has been synthesized hydrothermally based on a V-shaped ligand OPY. The structure was fully characterized by elemental analysis, FT-IR spectroscopy, and X-ray single-crystal diffraction analysis. In1, two OPY ligands and one water molecule acted as terminal ligands coordinating to Cdcation to form [Cd(OPY)HO]units, which are then linked by tdc2-ligands to generate a one-dimensional chain. Every two adjacent chains linked by extensive O–H···O hydrogen bonds constitute one-dimensional double-chains, and such chains are extended into two-dimensional layers via O–H···N hydrogen bonds. These layers are further connected to form a three-dimensional supramolecular architecture via π-π stacking interactions. In addition, the thermal stability and solid state fluorescence property of 1 were also investigated.

Fibrinogen Structural Changes Caused by Glass Surface Adsorption Detected by Solid Surface Fluorescence Spectroscopy

Solid surface fluorescence (SSF) spectra of fibrinogen (FG) adsorbed on a glass surface were measured. For comparison, solution fluorescence (SF) spectra of native, thermally denatured, urea denatured FG solution with FG desorbed from a glass surface and the SSF spectra of native FG powder were recorded. To analyze the structural changes induced by the surface adsorption, all the aqueous samples mentioned above were analyzed by circular dichroism (CD) spectroscopy. The results demonstrated that the structural changes of FG induced by glass adsorption caused changes in the spectroscopic features of the SSF spectra, especially in the excitation (EX) spectra. It is suggested that SSF spectroscopy may be a useful tool for studying the structures of surface/interface biomolecules and for evaluating the biocompatibility of biomaterials.

Rapid, simple and selective determination of 2,4-dinitrophenol by molecularly imprinted spin column extraction coupled with fluorescence detection

A rapid, simple and selective method based on molecularly imprinted, spin column extraction coupled with fluorescence detection was successfully established for the determination of 2,4-dinitrophenol in serum samples. The 2,4-dinitrophenol imprinted polymers exhibited highly selective recognition for the template molecule and the maximum adsorption capacity was 138.9 mg/g. The results indicated that when water is used as the loading solution, only 2,4-dinitrophenol could be adsorbed on the spin column without the remaining structural analogs（2-nitrophenol, 4-nitrophenol and phenol）. After eluting with acetonitrile/acetic acid（9/1, v/v）, 2,4-dinitrophenol in serum samples could be determined by using the fluorescence spectrometer, based on the fluorescence enhancement of fluorescein by the template molecule. Under the optimal conditions, the spiked recovery ranged from 95.8% to 103.4% and the detection limit was 1 nmol/L. The results confirmed the reliability and practicality of the protocol and revealed a good perspective of this method for biological sample analysis.