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As a highly toxic and widely used chemical, phosgene has become a serious threat to humankind and public security because of its potential use by terrorists and unexpected release during industrial accidents. For this reason, it is an urgent need to develop facile, fast, and selective detection methods of phosgene. In this Article, we have constructed a highly selective fluorescent sensor o-Pab for phosgene with a BODIPY unit as a fluorophore and o-phenylenediamine as a reactive site. The sensor o-Pab exhibits rapid response (15 s) in both colorimetric and turn-on fluorescence modes, high selectivity for phosgene over nerve agent mimics and various acyl chlorides and a low detection limit (2.7 nM) in solutions. In contrast to most undistinguishable sensors reported, o-Pab can react with phosgene but not with its substitutes, triphosgene and biphosgene. The excellent discrimination of o-Pab has been demonstrated to be due to the difference in highly reactive and bifunctional phosgene relative to its substitutes. Furthermore, a facile testing paper has been fabricated with poly(ethylene oxide) immobilizing o-Pab on a filter paper for real-time selective monitoring of phosgene in gaseous phase. [ABSTRACT FROM AUTHOR]

Two interesting dinuclear Zn(II)-compounds Zn 2 L 3 Cl 4 ( 1 ) and Zn 2 L 4 Cl 4 ( 2 ) were synthesized through the in situ zinc-induced reaction of simple pyridyl terminated (L 1 /L 2 )Schiff base ligands with ZnCl 2 in the mixture solvents of DMF and pyridine at 80 °C for three days (where L 1 = N-(2-pyridyl-methyl)-pyridine-2-carbaldimine, L 2 = 1-(pyridin-2-yl)-N-(pyridin-2-yl-methylene)ethanamine, L 3 = 2,3,5,6-tetra-(pyridin-2-yl)pyrazine, L 4 = 1,2-di(pyridin-2-yl)-bis(1-(pyridin-2-yl)-ethylidene)ethane-1,2-diamine). The elemental analysis (EA) and IR results reveal that in situ formation of one new ligand L 3 in 1 involves two C C coupling reactions from two molecular L 1 featuring H atom in α -carbon of C N moiety, while in situ formation of another new ligand L 4 in 2 involves one C C coupling reaction from L 2 featuring –CH 3 group in α -carbon of C N moiety. Obviously, different molecular structures between 1 and 2 closely related to the different substituents in simple Schiff base ligands. Moreover, the fluorescent properties of compounds 1 and 2 were also studied. [ABSTRACT FROM AUTHOR]

A new encoding strategy based on the host-guest structure was developed, where encoding is achieved by combinational use of a set of guest particles with different fluorescence intensity levels at various ratios. This system was proven to be well-defined and highly controllable. [ABSTRACT FROM AUTHOR]

The interaction of Ligupurpuroside A with bovine serum albumin (BSA) has been investigated by fluorescence spectra, UV-vis absorption spectra, three-dimensional (3D) fluorescence spectra, synchronous fluorescence spectra and circular dichroism (CD) spectra along with a molecular docking method. The fluorescence experiments indicate that Ligupurpuroside A can quench the intrinsic fluorescence of BSA through a combined quenching way at the low concentration of Ligupurpuroside A, and a static quenching procedure at the high concentration. The thermodynamic analysis suggests that hydrogen bonds and van der Waals forces are the main forces between BSA and Ligupurpuroside A. According to the theory of Förster׳s non-radiation energy transfer, the binding distance between BSA and Ligupurpuroside A was calculated to be 2.73 nm, which implies that energy transfer occurs between BSA and Ligupurpuroside A. All these experimental results have been validated by the protein-ligand docking studies which show that Ligupurpuroside A binds to the residues located in the hydrophobic cavity on subdomain IIA of BSA. In addition, conformation change of BSA was observed from three-dimensional fluorescence spectra, synchronous fluorescence spectra and circular dichroism spectra under experimental conditions. [ABSTRACT FROM AUTHOR]

Abstract: Two zinc(II) complexes with NO- and N2O-set oxime-containing Schiff base ligand of 2-hydroxyimino-N′-[1-(2-pyridyl)ethylidene]propanohydrazone (Hpop), namely [Zn3(pop)2-(CH3OH)2Cl4] (1) and [Zn(pop)Cl]4·(H2O)2 (2), have been successfully synthesized from the reaction of Hpop with ZnCl2 in CH3OH under different temperatures and fully characterized by X-ray single-crystal diffraction, EA and IR as well as TG. At the low temperature, the linear M3L2-type trinuclear Zn(II) compound 1 was obtained, however, the grid-like Zn4L4-type tetranuclear Zn(II) compound 2 was given at the high temperature from the same reactants. Interestingly, compound 1 may be irreversibly transformed into 2 via ring-closed coordination reaction under the high temperature, accompanied by the corresponding changes in fluorescent property. [Copyright &y& Elsevier]

Abstract: An immunoaffinity capillary column has been made with poly (2-vinyl-4, 4-dimethylazlactone-co-2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) (VDA-co-HEMA-co-EDMA) monolith as a support for the immobilized antibody. The monolith is prepared by UV-initiated in situ polymerization, followed by immobilizing anti-testosterone polyclonal antibody through the rapid reaction with VDA. Fluorescence labeled testosterone at C3 is designed as a tracer to estimate the extraction ability of this immunoaffinity column, and to optimize the immunoextraction process, such as washing, eluting, incubation and injection. The performance in a more realistic application is then demonstrated successfully for the rapid extraction of testosterone (T) by competitive immunoassay and on-line laser-induced fluorescence (LIF) detection. This immunoaffinity monolith is easily prepared, with high mechanical strength and low flow resistance. It is a satisfactory material as an immunoextractor to detect small molecular compounds specifically and rapidly with high sensitivity (sub ng/mL level). [Copyright &y& Elsevier]

The interactions of a metal complex [Ru(phen)2PMIP]2+ {Ru=ruthenium, phen=1,10-phenanthroline, PMIP=2-(4-methylphenyl)imidazo[4,5-f]1,10-phenanthroline} with yeast tRNA and calf thymus DNA (CT DNA) have been investigated comparatively by UV-vis spectroscopy, fluorescence spectroscopy, viscosity measurements, isothermal titration calorimetry (ITC), as well as equilibrium dialysis and circular dichroism (CD). Spectroscopic studies together with ITC and viscosity measurements indicate that both binding modes of the Ru(II) polypyridyl complex to yeast tRNA and CT DNA are intercalation and yeast tRNA binding of the complex is stronger than CT DNA binding. ITC experiments show that the interaction of the complex with yeast tRNA is driven by a moderately favorable enthalpy decrease in combination with a moderately favorable entropy increase, while the binding of the complex to CT DNA is driven by a large favorable enthalpy decrease with a less favorable entropy increase. The results from equilibrium dialysis and CD suggest that both interactions are enantioselective and the Δ enantiomer of the complex may bind more favorably to both yeast tRNA and CT DNA than the Λ enantiomer does, and that the complex is a better candidate for an enantioselective binder to yeast tRNA than to CT DNA. Taken together, these results indicate that the structures of nucleic acids have significant effects on the binding behaviors of metal complexes. [ABSTRACT FROM AUTHOR]

Deletion of the genes for four or five small Cab-like proteins (SCPs) in photosystem (PS) I-less and PS I-lessPS II-less strains of Synechocystis sp. PCC 6803 caused a large decrease in the chlorophyll and carotenoid content of the cells without accumulation of early intermediates in the chlorophyll biosynthesis pathway, suggesting limited chlorophyll availability. The PS II/PS I ratio increased upon deletion of multiple SCPs in a wild type background, similar to what is observed in the presence of subsaturating concentrations of gabaculin, an inhibitor of an early step in the tetrapyrrole biosynthesis pathway. Upon deletion of multiple SCPs, neither 77 K fluorescence emission properties of phycobilisome-less thylakoids from the PS I-less/PS II-less strain nor the energy trapping efficiency of PS II were affected, indicating that under steady-state conditions SCPs do not bind much chlorophyll and do not serve as PS II antenna. Under conditions where protochlorophyllide reduction and thus chlorophyll synthesis were inhibited, chlorophyll disappeared quickly in a mutant lacking all five SCPs. This implies a role of SCPs in stabilization of chlorophyll-binding proteins and/or in reuse of chlorophylls. Under these conditions of inhibited reduction of protochlorophyllide, the accumulation kinetics of this intermediate were greatly altered in the absence of the five SCPs. This indicates an alteration of tetrapyrro1e biosynthesis kinetics by SCPs. Based on this and other evidence, we propose that SCPs bind carotenoids and transiently bind chlorophyll, aiding in the supply of chlorophyll to nascent or reassembling photosynthetic complexes, and regulate the tetrapyrrole biosynthesis pathway as a function of the demand for chlorophyll. [ABSTRACT FROM AUTHOR]

A new fluorescent molecular probe 1 was designed and constructed by combining bovine serum albumin (BSA) and N , N′ -bis(salicylidene)ethylenediamine (salen). Stimulated by Zn 2 + , tris, or EDTAH 2 Na 2 , the distance between BSA and salen was regulated, which was accompanied by an obvious change in the fluorescence intensity at 350 or 445 nm based on Förster resonance energy transfer. Moreover, based on the encoding binary digits in these inputs and outputs applying positive logic conventions, a monomolecular circuit integrating one OR, three NOT, and three YES gates, was successfully achieved. [ABSTRACT FROM AUTHOR]

Abstract: Three isostructural lanthanide complexes, [Ln2(H2O)4(DMSO)](CuI)4(Ina)4(ox)[HIna=isonicotinic acid; H2ox=oxalic acid; Ln=Pr(1), Sm(2), Eu(3)], have been synthesized under the solvothermal condition and characterized by single-crystal X-ray diffraction, X-ray powder diffraction (PXRD), thermogravimetric analysis (TGA) and elemental analysis (EA) and IR spectra. Complexes 1–3 present 2-D pillar-chained frameworks and consist of two distinct chain-like motifs of inorganic [Cu4I4]n cluster chains and organic Ln-carboxyl-oxalic [Ln2(μ 2-Ina)2(Ina)2(μ 2-ox)]n chains. The 13C NMR of HIna indicates ox2− in 1–3 is generated by the in situ decomposition of HIna. Additionally, the photoluminescent properties of 1–3 are also discussed. [Copyright &y& Elsevier]

Six new metal–organic frameworks (MOFs), namely,[Pb(H2IDC)2(H2O)]n(1), {[Pb(H2IEDC)2)]·3H2O}n(2), [Ca2(HIDC)2(H2O)]n(3), {[Ca2(IEDC)2(H2O)2]·H2O}n(4), {[Cd(HIDC)(H2O)]n(5), and {[Cd2(HIEDC)2·3H2O}n(6) (H3IDC = 4,5-imidazoledicarboxylic acid, H3IEDC = 2-ethyl-1H-imidazole-4,5-dicarboxylicacid) were hydrothermally synthesized and characterized. Single-crystalX-ray diffraction shows the ligand H3IDC is partially deprotonatedwith H2IDC–and HIDC2–forms in three corresponding compounds 1, 3, and 5, meanwhile ligand H3IEDC also presentsdifferent deportonated motifs of H2IEDC–, IEDC3–, and HIEDC2–in 2, 4, and 6, respectively. Moreover,these partially or fully deportonated ligands coordinate in the μ1to μ5manner to generate one-dimensional(1D) → three-dimensional (3D) coordination polymers, displaying10 different coordination modes. Both 1and 2have 3D supramolecular networks assembled via hydrogen bonding interactionsbut different in structure topologies. Complex 1is a1D coordination chain and 2has a two-dimensional (2D)wave layer-like structure with 44topology. Complex 3is a 3D MOF with 310·425·510topology built up from linear 2-connected HIDC2–as a linker and 10-connected tetranuclear metal unit [Ca4(μ2-O)6] as a node. However, complex 4presents a 2D MOF with 36·46·53topology. Different from 3and 4, with the 4-connected binuclear metal unit [Cd(O–C–O)]2as a node, a wave-like 2D MOF with 44topologyin 5based on H3IDC is created. Complex 6shows a 3D coordination framework containing 1D alternatelyarranged hydrophilic channels including (H2O)4clusters and hydrophobic channels partially occupied by ethyl groupsfrom imidazole rings, in which the Cd(II) ion is viewed as a 4-connectednode, and HIEDC2–and μ2-O areregarded as two different linkers, 6showing 42·84topology. Obviously, these results reveal thatthe existence of the substitute groups of 2-position in such 4,5-imidazoledicarboxylateligand plays a critical role in the structural direction of theseMOFs. Meanwhile, the adsorption and photoluminescent properties ofthe selected compounds are investigated. [ABSTRACT FROM AUTHOR]

Large, high optical quality single crystals of ruby have been grown successfully by the floating zone method under air atmosphere. The size of the grown crystal is typically 60-70 mm in length and 7-8 mm in diameter. The obtained crystals were red and did not have any macroscopic defects such as cracks and inclusions. Grown crystals were characterized by powder X-ray diffraction (XRD) methods, polarized optical microscopy, scanning electron microscopy (SEM). The absorption and fluorescence spectra were measured at room temperature and the dielectric constant measurements of ruby crystals were also presented. Defects occurring in single crystals of ruby during crystal growth by floating zone method are described, and their correlation with the growth parameters is discussed. The origin and control of these defects in grown crystals were studied and the optimum method was proposed. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Several logic gates, which are commonly designed with DNA or organic molecules, rely on only one output mode. Here, a new molecular device was designed and constructed by combining bovine serum albumin and 5-sulfosalicylic acid. When MoO 4 2― , Tris(hydroxymethyl)aminomethane, EDTAH 2 Na 2 , Al 3+ , Trichloroacetic acid are used as inputs, changes in the fluorescent intensity at 350 nm and 406 nm were observed via FRET. Four molecular devices as a half-adder and three digital logic circuits were successfully constructed on the unimolecular platform by employing emission properties at different wavelengths as outputs. The advantage of the combined system was that many different functional molecular devices could be designed and assembled by employing protein and various organic molecules in aqueous solution. [ABSTRACT FROM AUTHOR]

Novel 3D barcodes with an extraordinarily high encoding capacity are developed through a flexible, accurate, and reproducible method. Here, the three dimensions refer to the size, fluorescence emission wavelength, and intensity of the barcodes. As a proof of concept, a 3D barcode library with an encoding capacity of 100 flow cytometry-distinguishable barcodes is achieved successfully by combining the multiscaled host particles with a set of guest nanoparticles owning to their individual different fluorescent intensity via an ingenious host-guest structure, where fluorescein isothiocyanate and a kind of quantum dots are separately loaded inside. Five-plexed tumor marker detection is further implemented, and the results demonstrate the strong feasibility of 3D barcodes in multiplex assays. [ABSTRACT FROM AUTHOR]

Abstract: Two new complexes based on 4-(benzimidazol-1-ylmethyl)benzoic acid (HL), (Sm2L6·H2O)n (1) and (LuL3)n (2), have been synthesized under the solvothermal condition and characterized by single-crystal X-ray diffraction, X-ray powder diffraction (PXRD), thermogravimetric analysis (TGA) and elemental analysis (EA) and IR spectra. The results show that both complexes are isomorphous and possess 2-D pillar-chained frameworks, consisting of 1-D triple-stranded double-helical (PPM/MMP) [Ln(η 2-O)(μ 2-OCO)2]n (Ln=Sm(1), Lu(2)) motif as chain and μ 3-(η 1:η 1:η 1)-bridging ligand L− as pillar, though they have different space groups of triclinic P-1 for 1 and monoclinic P21/c for 2. Two complexes represent the first example of 2-D lanthanide compound containing 4-(benzimidazol-1-ylmethyl)benzoic acid as the sole ligand. Additionally, the photoluminescent property of 1 is also discussed. [Copyright &y& Elsevier]