A Zn(Ⅱ) Coordination Polymer Based on a Flexible Symmetric Multicarboxylate Ligand

A novel coordination polymer, namely [Zn_2(CAPA)(DMA)(H_2O)]_(2n)·n(H_2O)(1,H_4CAPA = 5-(bis(4-carboxybenzyl) amino) isophthalic acid, DMA = N,N-dimethylacetamide) has been synthesized through a solvothermal method and characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectra, and thermogravimetric analyses. The crystal structure is of monoclinic, space group P21/n with a = 8.0585(5), b = 18.9733(10), c = 20.2044(14) ?, β = 101.144(7)o, V = 3030.9(3) ?~3, C_(56)H_(54)Zn_4N_4O_(21), M_r = 1378.58, Z = 2). The compound forms a three-dimensional(3D) supramolecular framework by linking adjacent layers via hydrogen bonds and π···π interactions. It is interesting that the crystal structure is much related to the flexibility and configuration of the ligand. In addition, the thermal stability and luminescence properties for the compound have also been investigated.     

A Novel Chemosensor for Fe(III) Based on Phosphorescence Quenched 9-Bromophenanthrene Induced by β-Cyclodextrin Combined with Flow Injection Renewable Drop

A novel phosphorescent chemosensor for Fe(III) based on room-temperature phosphorescence (RTP) using the method of flow injection renewable drop (FIRD) was developed. A RTP of 9-bromophenanthrene (BrP) can be induced by β-cyclodextrin (β-CD) in the presence of cyclohexane (CH); however, trace Fe(III) caused a decrease of the RTP emission. The optimal conditions were investigated. Under the optimal conditions, the analytical curve of Fe³⁺ gave a linear dynamic range of 4.0 × 10^?7 mol(L^?1～6.0 × 10^?4 mol(L^?1, with a detection limit of 36 μg/L. When the established CD-RTP method was applied to determine the concentrations of Fe(III) in synthetic samples, the experiment results demonstrated that the range of recovery was 97.3%–102%, with a relative standard deviation less than 2.05% (n = 6).     

A Three-dimensional Cd(Ⅱ) Coordination Polymer with Unique 8-Connected LOMFOI Topology Based on Mixed Flexible N/O Ligands

A new metal-organic framework,{[Cd(DPA)(OBA)]·(H2O)}n(1,DPA = 4,4-dipyridylamine,H2OBA = 4,4-oxybisbenzoic acid),has been synthesized and characterized by elemental analysis,IR and single-crystal X-ray diffraction.Single-crystal X-ray analysis shows that it is a 3-D framework.Complex 1 crystallizes in monoclinic,space group C2/c with a = 21.699(7),b = 12.192(4),c = 17.566(5) ,β = 105.254(5)°,V = 4483.43 3,Z = 8,Dc = 1.653 g/cm3,μ = 1.021 mm-1,F(000) = 2240,the final R = 0.0307,wR = 0.0867(I 2σ(I)).Complex 1 exhibits a rare three-dimensional highly 8-connected LOMFOI topology with a point symbol of {424·64}.Thermogravimetric analysis shows that the decomposition temperature of the host framework of the complex is above 400 ℃.     

A Dicyanamido-bridged Zinc(Ⅱ) Complex Based on the Bis(4-pyridyl)ethane with a Three-dimensional Framework

A novel dicyanamido-bridged 3D polymeric complex {[Zn2(bpa)2(dca)]dca}n (1) (dca = dicyanamide anion,bpa = 1,2-bis(4-pyridyl)ethane) has been synthesized by reacting 1,2-bis(4-pyridyl)ethane with zinc salt in the presence of sodium dicyanamide,and characterized by elemental analysis,IR spectra and X-ray diffraction. It crystallizes in the monoclinic system,space group C2/c with a = 18.587(3),b = 20.070(3),c = 8.7957(13) ,β = 100.611(2)o,V = 3225.0(8) 3,Mr = 539.92,μ = 0.789 mm-1,F(000) = 1116,Z = 4,ρ = 1.112 (g/cm3),R = 0.0582 and wR = 0.1762. Complex 1 forms a 3D porous framework through the bpa and dca ligands,and gives 1-D coordination channels encapsulated by the guest dca molecules. Complex 1 also displays strong photo-luminescent properties in the solid state at room temperature.     

A Convergent Synthesis of (±)-Eldanolide Based on Reaction of Aldehyde with Dithio-Substituted Crotyllithium Compound

Reaction of lithium anion of E-2-(1′-propen-1′-yl)-1,3-dithiane and 4-methyl-3-pentenal afforded a single product, which was converted in high yield to a wing gland pheromone, (±)-eldanolide.     

A New Three-dimensional Zn(Ⅱ) Coordination Polymer Based on Trinuclear Zn(Ⅱ) Units with a Three-fold Hex Topology

Under solvothermal conditions, a new trinuclear Zn(II) complex, [Zn3(bpdc)3(DPNDI)]· 3NMF(1, H2 bpdc = biphenyl-4,4-dicarboxylate, N,N-di(4-pyridyl)-1,4,5,8-naphthalenetetracarboxydiimide(DPNDI) and NMF = N-methylformamide), has been synthesized with mixed organic ligands. Complex 1 is of monoclinic, space group P21/n with a = 11.167(5), b = 14.806(5), c = 19.494(5) , V = 3154.6(19) 3, Z = 2, Mr = 1455.24, Dc =1.532 g/cm3, F(000) =1484 and μ = 1.212 mm1. The final refinement gave R = 0.0343 and w R = 0.0419 for 6209 reflections with I 2(I). Single-crystal X-ray analysis reveals that complex 1 features a 3D structure based on the trinuclear Zn(II) units. Complex 1 shows three-fold interpenetrating hex topology. Furthermore, the luminescent property 1 is investigated.     

A Novel Two-dimensional Lead(Ⅱ) Coordination Polymer Based on Dinuclear Lead(Ⅱ) Unit Containing(5-Chloro-quinolin-8-yloxy) Acetate

A novel two-dimensional lead(II) coordination polymer 1, [C11H7Cl2NO3Pb]n, has been prepared by solvothermal reaction of new bridging ligand(5-chloro-quinolin-8-yloxy)acetic acid(HL) with PbCl2, and its structure was characterized by IR, elemental analysis, TG-DTA and single-crystal X-ray diffraction analysis. The crystal is of monoclinic system, space group P21/c with a = 16.7603(7), b = 8.6907(4), c = 8.4745(3), β = 101.1110(11)°, C11H7Cl2NO3 Pb, Mr = 479.27, V = 1211.25(9)3, Z = 4, Dc = 2.628 g/cm3, F(000) = 880, μ = 14.367 mm-1, R = 0.0173 and wR = 0.0508. The asymmetric unit contains one lead(II) cation, one(5-chloro-quinolin-8-yloxy)acetate(L) ligand and a chloride ion. The PbII center is hepta-coordinated in a distorted pentagonal bipyramidal geometry. The coordination sphere of the Pb atom is completed by two oxygen atoms and one nitrogen atom of the same L ligand, two bridging chloride ions and two bridging oxygen atoms of two adjacent L ligands. Two PbII centers are linked by the two L ligands to form a C2-symmetric dimer unit with a planar [Pb2O2] ring. Each dimer unit acts as a secondary building unit(SBU) and links adjacent four dimer units by the chloride atoms and oxygen atoms of carboxylate groups of L, forming a two-dimensional array. Such two-dimensional layers are packed through intermolecular C–H···Cl hydrogen bonds into a three-dimensional supramolecular structure. When the dimer unit is viewed as a 4-connected node, 1 is simplified as a 4-nodal 2-D network with square lattices of the diagonal lengths to be 6.079(1). The fluorescence emission peak of complex 1 appears near 407 nm.     

A Novel Proton Sensor with Luminescence and Color Signaling Based on Platinum(II) Terpyridyl Acetylide Complex

Molecular switches that are controllable, reversible and readable at molecular level are an essential compo-nent of molecular electronics1 and chemical sensors.2-6 Of particular interest are the molecules which show dramatic and reversible changes in color and/or lumi-nescence in visible spectral region upon exposure to specific substrates. A number of chromophore- spacer-receptor systems that can selectively recognize specific guest molecules at their receptor site and pro-duce measurable col…     

Studies on extraction of In(Ⅲ) with 8-hydroxyquinoline

The equilibrium molalities of In3 in extraction reaction: In3 (aq) 3HOx(org) = In(Ox)3(org) 3H (aq) were measured at ionic strengths from 0.13 to 2.54 mol-kg-1 in the aqueous phase containing Na2SO4 as the supporting electrolyte and at constant initial molality of extractant, HOx, in the organic phase at temperatures from 278.15 to 308.15 K, where HOx and Ox mean 8-hydroxy-quinoliue and its anion, respectively. The standard extraction constants K0 at various temperatures were obtained by two methods proposed in our previous paper.     

Comparison of Estrogen Receptor α and β Subtypes Based on Comparative Molecular Field Analysis (CoMFA)

Abstract

A substantial body of evidence indicates that both humans and wildlife suffer adverse health effects from exposure to environmental chemicals that are capable of interacting with the endocrine system. The recent cloning of the estrogen receptor β subtype (ER-β) suggests that the selective effects of estrogenic compounds may arise in part by the control of different subsets of estrogen-responsive promoters by the two ER subtypes, ER-α and ER-β. In order to identify the structural prerequisites for ligand-ER binding and to discriminate ER-α and ER-3 in terms of their ligand-binding specificities, Comparative Molecular Field Analysis (CoMFA) was employed to construct a three-dimensional Quantitative Structure-Activity Relationship (3D-QSAR) model on a data set of 31 structurally-diverse compounds for which competitive binding affinities have been measured against both ER-α and ER-β. Structural alignment of the molecules in CoMFA was achieved by maximizing overlap of their steric and electrostatic fields using the Steric and Electrostatic ALignment (SEAL) algorithm. The final CoMFA models, generated by correlating the calculated 3D steric and electrostatic fields with the experimentally observed binding affinities using partial least-squares (PLS) regression, exhibited excellent self-consistency (r ² > 0.99) as well as high internal predictive ability (q ² > 0.65) based on cross-validation. CoMFA-predicted values of RBA for a test set of compounds outside of the training set were consistent with experimental observations. These CoMFA models can serve as guides for the rational design of ER ligands that possess preferential binding affinities for either ER-α or ER-β. These models can also prove useful in risk assessment programs to identify real or suspected EDCs.     

Synthesis of A novel Bridged Bis(β-cyclodextrin)s Possessing Phenanthroline Tether and Its Molecular Binding Ability with Dyes

A novel β-cyclodextrin dimer bearing 2,9-diformyl-1,10-phenanthroline tether 4 has been synthesized and its inclusion complexation behavior with two triangular model substrates (RhB and BG) has been investigated through fluorescence and ultraviolet spectrometry.The result obtained indicated that novel bridged bis(β-cyclodextrin)s could significantly cnhance the original molccular binding ability of native β-cyclodextrin by cooperative binding of two hydrophobic cavities.     

Two Novel Mercury(Ⅱ) and Copper(Ⅱ) Complexes Based on(5-Chloro-quinolin-8-yloxy)acetic Acid

Two novel mononuclear complexes with 5-chloro-8-(methoxycarbonylmethoxy)quinoline ligand(L), namely, HgLBr_2 1 and CuL_2Cl_2 2, have been prepared by solvothermal reaction of(5-chloro-quinolin-8-yloxy)acetic acid with HgBr_2 and CuCl_2, respectively. Their structures were characterized by IR, elemental analysis, UV-Vis-NIR spectra, TG and single-crystal X-ray diffraction analysis. Interestingly,(5-chloro-quinolin-8-yloxy)acetic acid is changed as 5-chloro-8-(methoxycarbonylmethoxy)quinoline ligand(L) in complexes 1 and 2. Crystal data for 1: C12H10Br2 Cl Hg NO3, Mr = 612.07, triclinic, space group P1 with a = 8.5983(7), b = 9.7726(6), c = 10.1549(6) ?, α = 66.355(6), β = 77.067(8), γ = 78.803(8)°, V = 756.6(9) ?3, Z = 2, Dc = 2.687 g/cm3, F(000) = 560, μ = 15.633 mm-1, R = 0.0351 and w R = 0.0504. Crystal data for 2: C24H20Cl4 Cu N2O6, Mr = 637.76, triclinic, space group P1 with a = 10.5324(9), b = 11.2377(16), c = 12.0143(12) ?, α = 83.413(11), β = 64.475(9), γ = 83.144(11)°, V = 1270.9(2) ?3, Z = 2, Dc = 1.667 g/cm3, F(000) = 646, μ = 1.324 mm-1, R = 0.0408 and w R = 0.0922. In 1, the HgII centre is a distorted trigonal planar geometry comprised of two Br atoms and one quinoline N atom of L. Intermolecular π-π, C–H···π stacking interactions and intermolecular C–H···Br hydrogen bonds are observed in the molecular packing of 1. In complex 2, each CuII center has a distorted octahedral geometry comprised of two chloride ions, two quinoline N atoms and two O atoms of two L ligands. Intermolecular C–H···Cl hydrogen bonds exist in the molecular packing of 2. The fluorescence emission peak of complexes 1 and 2 appears near 406 and 410 nm, respectively. Optical diffuse-reflection spectral results suggest complex 1 has the property of semiconductor.     

3D-QSAR Study on Diindolylmethane and Its Analogues with Comparative Molecular Field Analysis (CoMFA)

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Syntheses and Crystal Structure of a New Molecular Clip Based on Diethoxycarbonyl Glycoluril: C_(54)H_(38)N_8O_6·H_2O

A new glycoluril derivative 2 has been synthesized and characterized by singlecrystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 13.128(7), b = 13.245(7), c = 14.016(8) ?, α = 98.805(10), β = 102.036(9), γ = 101.470(10)°, V = 2287(2) ?3, Z = 2, C54H38N8O6·H2O, Mr = 912.94, F(000) = 952, T = 298(2) K, Dc = 1.326 g/cm3 and μ = 0.090 mm-1. Due to the intermolecular C–H...O interactions, two monomeric molecular clips dimerize as a dimeric building block in the crystalline state. Those building blocks form tape-like supramolecular polymers driven by intermolecular C–H...N interactions and water molecules which stabilized in the packing structure served as hydrogen-bonding donors.     

Molecular Recognition of Bridged Bis(β-cyclodextrin)s Linked by Phenylenediseleno Tether on the Primary or Secondary Side with Fluorescent Dyes

A Novel β-cyclodextrin dimer,2,2′-o-phenylenediseleno-bridgedbis(β-cyclodextrin)(2),has been synthesized by reaction ofmono-[2-O-(p-tolylsulfonyl)]-β-cyclodextrin and poly(o-phenylenediselenide).The complexation stability constants(K_s)and Gibbs free energy changes(-ΔG°)of dimer 2 with fourfluorescence dyes,that is,ammonium 8-anilino-1-naphthalene-sulfonate(ANS),sodium 6-(p-toluidino)-2-naphthalenesul-fonate(TNS),Acridine Red(AR)and Rhodamine B(RhB)have been determined in aqueous phosphate buffer solution(pH=7.2,0.1 mol·L~(-1)at 25℃ by means of fluorescence spec-     

A Molecular Modeling for the Complexation of Cyclobis(paraquat-p-phenylene) with Substituted Benzenes and Biphenyls

The molecular recognition of cyclobis(paraquat-p-phenylene), 14+, has drawn great attention recently, due to its important applications in the design and synthesis of electrochemically and chemically switchable rotaxanes, photoactive rotaxanes, and other molecular devices1. Usually, this type of molecular recognition was investigated with the methods including X-ray, NMR, UV, and IR. However, since these methods usually have difficulties in providing a detailed understanding of the energeti…     

Room-Temperature Silicon Nitrides Prepared with Very High Rates (>50 nm/s) in Atmospheric-Pressure Very High-Frequency Plasma

We have investigated the structure and stability of SiN _x films deposited with very high rates (>50 nm/s) in atmospheric-pressure (AP) He-based plasma excited by a 150 MHz very high-frequency (VHF) power using a cylindrical rotary electrode at room temperature. The SiN _x films are prepared on Si(001) substrates with varying VHF power density (P _VHF), H₂ concentration and source ratio (NH₃/SiH₄). Infrared absorption spectroscopy is used to analyze the bonding configurations in the films. The results show that increasing H₂ concentration under the supply of a moderately large P _VHF, together with the adjustment of NH₃/SiH₄ ratio, enables us to prepare SiN _x showing reasonable stability against a buffered hydrofluoric acid solution in spite of the very high deposition rate of 130 nm/s. The achievement of such a high-rate deposition at room temperature is primarily due to the significant enhancement of both gas-phase and surface-phase reactions in AP-VHF plasma.