Novel colorimetric sensor for mercury (Ⅱ) based on layer-by-layer assembly of unmodified silver triangular nanoplates

A simple layer-by-layer deposition technique was used to fabricate the multilayer thin films of unmodified silver triangular nanoplates(AgTNPs).The multilayer of AgTNPs thin films were fabricated by alternate deposition of each anionic sodium citrate stabilized AgTNPs and cationic poly(diallyldimethylammonium chloride).All prepared AgTNPs multilayer thin films were exhibited a strong plasmon band at the wavelength of 667 nm,which confirmed the formation of AgTNPs onto the substrate.The characteristics of the multilayer thin films were investigated using contact angle measurement,UV-visible spectroscopy,X-ray diffraction analysis(XRD),atomic force microscope(AFM)and field emission scanning electron microscope(FESEM).As these films are to be used as a mercury(II)colorimetric sensor,the changes in optical properties of the films were evaluated for various mercury(Ⅱ)concentrations.AgTNPs assembled into thin films showed a strong color shift from blue to mauve and colorless when exposed to mercury(Ⅱ).The constructed multilayer thin films exhibited excellent color changes of mercury(II) with a linear range between 0.5 and 20 ppm.The limit of detection(LOD) and limit of quantitation(LOQ) were 0.45 ± 0.002 and 1.52 ± 0.002 ppm,respectively.The recovery values of AgTNPs multilayer thin films are satisfactory in the range of 100.1%-106.4%when applied to determining mercury(Ⅱ) in water samples.     

Assembly-enhanced triplet-triplet annihilation upconversion in the aggregation formed by Schiff-base Pt(Ⅱ) complex grafting-permethyl-β-CD and 9,10-diphenylanthracence dimer

Water-soluble triplet sensitizer with permethyl-β-cyclodextrin(PMCD) grafting on a Schiff-base Pt(Ⅱ)complex(Pt-2),in which PMCD unit serves as a host for binding the acceptors and the Schiff-base Pt(Ⅱ)complex serves as a triplet sensitizer,was synthesized to investigate the effect of supramolecular complexation and assembly on the triplet-triplet annihilation upconversion emission in water.9,10-Diphenylanthracence(DPA) carboxylate(A-1) and its dimer(A-2) in which two DPA carboxylate were covalently linked with an alkyl chain were synthesized as triplet acceptors which also play a role of guest molecules for PMCD.A-1 and A-2 showed high affinity with PMCD,and A-2 can readily aggregate in water and form micron sized assemblies due to the hydrophobic effect and π-π stacking of anthracene core in A-2.The efficiency of TTA-UC was demonstrated to be enhanced by a synergistic effect of host-guest complexation of Pt-2 with A-2 and the self-aggregation of the acceptor A-2,which facilitated the energy transfer and energy fusion among donor and acceptor.     

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.     

Structures and Spectroscopic Properties of(1)Dipyridine Quinoxaline with Hg(Ⅱ), Cu(Ⅰ) and Ag(Ⅰ)

The interaction of Hg(Ⅱ), Cu(Ⅰ) and Ag(Ⅰ) with dipyridine quinoxaline ligand 2,3-bis(2-pyridyl)quinoxaline(DPQ) were investigated, and three new complexes have been synthesized and characterized. Complex 1 exhibits a 0D dual-core structure, complex 2 is a 0D tetra nuclear case based on a dual-core Cu unit, and complex 3 shows a one-dimensional pipeline structure. Furthermore, the optical properties of complex and DPQ were also investigated, and the results showed that the fluorescence intensity of complexes was weaker than that of ligand DPQ.     

Inclusion property and Diels-Alder reaction of bis (diphenylphosphine oxide) butadiyne

The host molecule, bis (diphenylphosphine oxide) butadiyne (2), includes a variety of guests to form five complexes (2a-2e). In addition, the Diels-Alder reaction between 2 and anthracene gives 9, 9', 10, 10'-tetrahedron-9, 9', 10, 10'-bi-ethenoantracene-11, 11'-bis ( diphenylphosphine oxide) (3) which is a potential di-π-methane reactant and can undergo photorearrangement.     

STUDIES ON THE CRYSTAL STRUCTURE OF Al-(D-TRYPTOPHAN) INSULIN

We have determined the crystal structure of Al-(D-Trp) insulin and discovered that it belongs to the trigonal system with space group R3. The parameters of the unit cell are a=b=78.6, c=50.0. A set of data for half a sphere reciprocal space to a spacing of 2.2 were collected. The model was adjusted and refined by using a step-by-step approach and a stereochemically-restrained least squares program, assisted by manual revision based on the difference Fourier maps, to a final R-factor of 0.218. The main and side chains of both Al-D-Trp residues in the asymmetric unit are well ordered. The packing of Al-(D-Trp) insulin in the unit cell, the conformational differences with other insulin structures and its structure and function relationship bave also been discussed.     

1-Pyrenecarboxaldehyde thiosemicarbazone:A novel fluorescent molecular sensor towards mercury(Ⅱ) ion

<正>A novel and simple fluorescent molecular sensor,1-pyrenecarboxaldehyde thiosemicarbazone(Hpytsc),was synthesized.Its higher sensitivity and selectivity to mercury(Ⅱ) ion were studied through absorption and emission channels.The UV-vis spectra show that the increasing mercury(Ⅱ) ion concentrations result in the decreasing absorption intensity.The fluorescence monomer emission of Hpytsc is enhanced upon binding mercury(Ⅱ) ion,which should be due to the 1:1 complex formation between Hpytsc and metal ion.     

Electrochemical Behavior of meso-Tetra (4-Sulfonatophenyl) Porphyrin and Its Copper Complex

The complex of Cu-TPPS was formed directly by mixing equal-molar concentrations of Cu~(2+) and meso-tetra(4-sulfonatophenyl) porphyrin(TPPS)in an acetate buffer solution at pH 4-6, and its electrochemical behavior was studied by the techniques of polarography, cyclic voltammetry and spectroelectrochemistry. Three different methods were applied to accelerating the formation of Cu-TPPS in aqueous solution, i.e. heating of solution,using vitamin C as a catalyst and preadsorbing TPPS on a hanging mercury electrode. The voltammetric reductions have shown 2e~- for the first step of TPPS and 4e~- for Cu-TPPS with a peak potential at -1.04V. By applying the method of spectroelectrochemistry using a selfdesigned long-optical-path cell with Hg working electrode, the amount of saturated adsorption of TPPS and Cu-TPPS on mercury surface is found to be the same. Hence, the area of the adsorbed molecule calculated by measuring the area (i×t) under the voltammetric peak is also the same as 395 (?)~2.     

MOF-derived Cu_2O/Cu NPs on N-doped Porous Carbon as a Multifunctional Sensor for Mercury(Ⅱ) and Glucose with Wide Detection Range

Cu_2O/Cu nanoparticles(NPs) in the nanoporous carbon matrix(designated as Cu_2O/Cu@NPC) has been synthesized by in-situ calcination of a cupper-based metal-organic framework(Cu-MOF), and its morphology and composition were characterized by PXRD, SEM and Raman. Furthermore, elemental mapping and XPS analysis not only show Cu NPs is generated along with nitrogen(N)-doped carbon, but also indicate Cu_2O NPs locates in the external layer of Cu@NPC. In addition, the adsorption of dye studies implies that Cu_2O/Cu@NPC exhibits obvious interaction with Rhodamine B(Rh B) due to the feature of porous and N-doped structure. Cu_2O/Cu@NPC has highly electrocatalytic performance for glucose and mercury(Ⅱ) with wide detection range and good stability, which can be used as a novel multifunctional sensor for glucose and mercury(Ⅱ).     

High Sensitive Spectrophotometric Determination of Trace Amounts of Ru( Ⅲ ) with α,β,γ,δ-Tetrakis(4-Trimethylammoniumphenyl) Porphyrin

Spectrophotometry usually has a high sensitivity in determining the complexation of TAPP with metal ions. Therefore, as an excellent color-producing reagent, TAPP has already been used for the spectrophotometric determination of trace amounts of mercury (Ⅱ), cobalt (Ⅱ), manganese(Ⅱ), zinc (Ⅱ) and cadmium (Ⅱ)etc..     

Cyanide-bridged One-dimensional Heterobimetallic Complex cis-[Fe~Ⅱ(phen)_2(CN)_2Mn~Ⅲ(salen)](PF_6): Synthesis,Crystal Structure and Magnetic Properties

Dicyanide building block cis-Fe(phen)_2(CN)_2 and [Mn~Ⅲ(salen)](ClO_4) have been used to design and synthesize a cyanide-bridged complex, resulting in a heterobimetallic one-dimensional(1D) zigzag chain complex 1, [cis-Fe(phen)_2(CN)_2Mn(salen)](PF_6)(phen =1,10-phenanthroline, salen=N,N?-ethylenebis-(salicylideneaminato) dianion). Single-crystal X-ray diffraction analysis shows complex 1 crystallizes in the monoclinic P2_(1/c) space group and the asymmetric unit contains one [-NC-Fe(phen)_2(μ-CN)-Mn~Ⅲ-(salen)-]~+ cation and one PF_6~- anion. In the cationic structure of 1, each Fe~Ⅱ(phen)_2(CN)_2 connects two [Mn~Ⅲ(salen)]~+ with two cyanide groups in a cis-conformation, and in turn each [Mn~Ⅲ(salen)]~+ unit links two Fe~Ⅱ(phen)2(CN)_2 building blocks in a trans-conformation, resulting in a 1D [-NC-Fe~Ⅱ-CN-Mn~Ⅲ-]n chain. Furthermore, the electronic absorption spectra and electrochemical and magnetic properties of complex 1 have also been studied.     

Synthesis,Characterization and Crystal Structure of (PhCH2)2Sn(S2CENt2) and (PhCH2)2Sn(S2CNC4H8)2

Two new dibenzyltin bisditiocarbamates(PhCH2)2 Sn(S2CNEt2)2(1) and (PhCH2)2 Sn(S2CNC4H8)2(2) were synthesized by the reaction of dibenzyltin dichloride with dithiocarbamates and characterized by elemental analysis ,IR,^1H NMR and MS spectra.The crystal structures were determined by X-ray single crystal diffraction analysis.In both complexes,the tin atom is six-coordinated in a distorted octahedral configuration.In the crystals of 1,the molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two Sn S interactions of 0.3816nm.In the crystals of 2,the molecules are packed in the unit cell in one-dimensional chain structure linked by weaker intermolecular S S conmtacts.     

Effects of humic acids and microorganisms on decabromodiphenyl ether, 4,4′-dibromodiphenyl ether and anthracene transportation in soil

In this study, effects of humic acids (HA) and microorganisms on the migration of hydrophobic organic contaminants (HOCs), decabromodiphenyl ether (BDE-209), 4,4′-dibromodiphenyl ether (BDE-15) and anthracene, in soils were examined. More soil particles were dispersed into the colloidal phase (0.22-1 μm) in the presence of HA and/or microorganisms as a result of increased erosion and friction. The study suggested that PBDEs (BDE-209 and BDE-15) and anthracene in soils would be transported to other places by...     

Synthesis and Crystal Structure of a Novel Bis(chlorido)-bridged One-dimensional Chain-like Copper(Ⅱ) Polymer

A copper(Ⅱ) complex [LCu_2Cl_4]n was synthesized by a new bis-Schiff base ligand containing quinoline unit, 1,4-bis[2-(4-fluorophenyl)iminomethyl-8-quinolinoxy]butane(L). X-ray crystal structure shows that it is a binuclear complex, and the crystal belongs to the triclinic system, space group P1, with a = 9.387(2), b = 9.968(2), c = 10.291(2) ?, α = 87.532(3), β = 63.762(2), γ = 86.628(3)o, V = 862.1(3) ?~3, Z = 1, Dc = 1.640 Mg/m~3, F(000) = 428, R = 0.0416 and wR = 0.1141. Each Cu(Ⅱ) metal ion coordinates with a quinoline N atom, an imine N atom, an ether oxygen atom and three chlorides, forming a distorted six-coordinated octahedronal structure. Each copper(Ⅱ) complexation unit links with one of the adjacent ligand copper complexation units through the chlorido bridging groups, thus generating an infinite one-dimensional chain structure. Such 1D chains further construct a 2D network structure by π-π stacking interactions.     

White and Red Organic Light Emitting Materials

Derivatives of 2,3-(1,4-dialkoxyaceno)norbornadiene underwent ring-opening metathesis polymerization (ROMP) upon the catalysis of a ruthenium complex to afford the corresponding polymers. The polymeric materials containing anthracene chromophores emit white electro-luminescence, which can be fabricated into light-emitting diodes (LED). The broad emission band is composed of a blue emission from anthracene and a red emission from aggregates. A single layer device, ITO/polymer/Ca/Al, can be…     

Small-angle X-ray scattering study of a poly(oxyphenylethylene)–poly(oxyethylene) diblock copolymer gel under shear flow

 The structure and flow behaviour of a micellar “cubic” phase is studied, using small-angle X-ray scattering (SAXS) and constant stress rheometry on a poly(oxyphenylethylene)–poly(oxyethylene) diblock copolymer in water. The predominant structure is a face-centred cubic (fcc) array of spherical micelles, which under shear undergoes layer sliding to give a scattering pattern from stacked hexagonal close-packed layers. A detailed analysis of the SAXS data indicates the presence of a fraction of grains with a structure distorted from a fcc phase. The additional reflections that characterize this structure can be indexed to a rhombohedral unit cell, space group R3ˉm, with the same volume as the fcc unit cell. The rhombohedral unit cell corresponds to a cubic cell that has been “stretched” along a [111] direction, and it is suggested that such a structure results from the gradient in shear velocity in the Couette cell employed. Shearing at high shear rates leads to a “smearing out” of the reflections, but upon cessation of shear under these conditions a highly oriented SAXS pattern is obtained, which confirms the persistence of rhombohedral ordering. The shear-induced changes in orientation are correlated to a plateau observed in the stress plotted against shear rate, such a plateau being a sign of inhomogeneous flow. Received: 8 September 2000 Accepted: 29 November 2000     

CRYSTAL STRUCTURE INVESTIGATION OF VANADYL COMPLEXES OF TRIDENTATE LIGAND (Ⅰ)——THE CRYSTAL STRUCTURES OF BIS[(1-(2,4-PENTANE- DIONATO(NITROBENZOYL) HYDRAZONE)-2- ETHOXY)OXOVANADIUM] AND BIS-[(1-(2, 4-PENTANEDIONATO-(3-NITROBENZOYL) HYDRAZONE)-2- METHO

The title complexes were obtained by the reactions of bis(2,4-pentanedionato)oxovanadium VO(Acac)_2 and m-nitrophenylhydrazide m-NO_2PhCONHNH_2 in the media EtOH and MeOH respectively. The compound (Ⅰ) crystallizes in the space group PT with unit cell dimensions a=8.123(2), b=10.409(5), c=10.822(4), α=65.78(3)°, β=85.50(3)°,γ=89.04(3)°. The compound (Ⅱ) crystallizes in the space group P2_1/a with unit cell dimensions a=7.745(2), b=19.164(5), c=10.787(4), β=107.87(2)°. The resuhs of structural analyses show that the two compounds have the same characteristics: the tridentate ligand formed by condensation occupies three of the four equatorial positions of vanadium and the rest equatorial position is occupied by alkoxy group RO~-. As RO~-group also bridges the sixth coordinated position of each vanadium atom, it brings about the formation of the new type binuclear complexes of vanadium.     

CRYSTAL AND MOLECULAR STRUCTURE OF TETRAKIS(THIPHENYLPHOSPHINE OXIDE)-DICHLORO-GADOLINIUM(Ⅲ)TRICHLOHO-COPPER(Ⅱ)

<正> The crystal of tetrakis(triphenylphosphine oxide)-dichloro-gadolinium trichloro-copper belongs to triclinic, space group Pl with unit cell parameters of a = 19.395(2), b = 19.708(5), c = 20.609(4)A,α= 63.32(2)° ,β=88.74(1)°,γ=81.49(1)°,V=6943.8A3,and Z=4. The final refinement converges with R=0.072 and Rw = 0.077 for 7870 observed independent reflections.     

Studies on the Crystal Structure and Photoluminescence of a Mercury(Ⅱ)Complex Based on a Novel Pyridine Ligand

<正>A novel mercury(n)complex HgL_2Br_2 was prepared from HgBr_2 and the organic ligand 2-(N-methyl-N-(4-((E)-2-(pyridine-4-yl)vinyl)phenyl)amino)ethanol(L).The ligand was synthesized and then characterized by FT-IR spectroscopy,~1H NMR,mass spectrum and elemental analysis,while the single-crystal diffraction data of the complex were collected on a Siemens Smart CCD diffractometer.The complex crystallizes in triclinic space group P_1~-with a=5.367(5),b= 12.466(5),c=23.945(5)(?),α=90.812(5),β=96.318(4),γ=96.093(5)°,Z=2,D_c=1.817g·cm~(-3),μ=7.395 mm~(-1),S=0.825,and the final R=0.0396.The Hg(Ⅱ)ion in the distorted tetrahedral mercury(Ⅱ)complex C_(32)H_(36)HgBr_2N_4O_2 is coordinated by two N atoms from the two ligands together with two bromide ions.Solid-state emission of the ligand and its complex has been investigated at room temperature.     

First Total Synthesis of (±)-Aiphanol

Aiphanol was isolated from the seeds of Aiphanes aculeate Willd. (Arecaceae) collected in Peru and was reported to exhibit significant inhibitory activities against cyclooxyge- nases-1 and -2. The structure of aiphanol was elucidated by spectroscopic methods as an unprecedented stilbenolignan skeleton in which a stilbene moiety is linked to a phenylpropane unit through a dioxane bridge1. In our previous works the synthetic approach to 1,4-benzodioxane lignans were achieved2. Since aiphanol…