- Linear and V-shaped carbazole-based molecules functionalized by cyano acceptors and diversified donors: Synthesis, single- and two-photon related photophysical properties
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A series of novel linear and V-shaped carbazole-based molecules functionalized by cyano acceptors and diversified donors (carbazole, diphenylamino, dimethylamino, methoxy, and ferrocene) were synthesized and characterized by hydrogen-1 nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, Fourier transform infrared spectroscopy, and high-resolution mass spectrometry. Their linear and nonlinear optical properties including UV–visible absorption, single-photon excited fluorescence, two-photon absorption, and frequency up-converted fluorescence, were systematically investigated in various solvents. The time-resolved photoluminescence studies using time-correlated single photon counting revealed their fluorescence lifetimes in THF. The solvent polarity exerts little effect on their absorption properties, while the emission properties (maximum fluorescence wavelength, Stokes shift, fluorescence quantum yield) display solvent polarity dependencies. Donor-acceptor functionalities and molecular dimensionality are considered to be the crucial structural factors that influence their optical properties. Pumped by a femtosecond laser (690–990 nm, 80 MHz, 140 fs), all the target molecules emit intense frequency up-converted fluorescence except FC1 and FC2 which contain one or two ferrocene donors. The two-photon absorption cross-sections in THF are in the range of 631–3014 GM. The density functional theory calculations were also conducted to unravel their electronic structures and to further understand the structure-property relationships. To our knowledge, this study is the first to be concerned with the single- and two-photon related photophysical properties of these D-π-A-π-D′ and D′-π-A-π-D-π-A-π-D′ carbazole-based molecules (D = donor, A = acceptor, π = conjugated bridge).
- Cai, Zhi-Bin,Liu, Shuang-Shuang,Li, Bo,Dong, Qi-Ji,Liu, Zi-Long,Zheng, Min,Li, Sheng-Li,Tian, Yu-Peng,Chen, Li-Jun,Ye, Qing
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- A high efficiency pure organic room temperature phosphorescence polymer PPV derivative for OLED
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For the purpose of improving device efficiency and reducing cost, it is necessary to develop pure organic molecules with room temperature phosphorescence (RTP). A high efficiency pure organic RTP polymer, poly-p-phenylene vinylene (PPV) derivative (Br-PPV-CHO), was designed and synthesized, which possesses a blue emission at 496 nm, an emission lifetime of 14.1 μs, and a photoluminescence quantum yield of 12.2%, and the HOMO and LUMO of ?5.35 eV and ?2.75 eV, respectively, showing a great potential application in the emitting layer of OLED. A device fabricated with the PPV derivative as the emitting material layer shows a max luminance of 194 cd/m2 when the Br-PPV-CHO content was 0.5 wt %, demonstrating the best RTP performance. The good properties of Br-PPV-CHO come from the substituent groups of bromine and aromatic aldehyde, and the molecular structure design strategy in the PPV derivative supplies a useful guidance for the design and syntheses of organic RTP materials.
- He, Ying,Cheng, Nianhe,Xu, Xin,Fu, Jiawei,Wang, Jun-an
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- A Series of Lanthanide Coordination Polymers Based on Designed Bifunctional 1,4-Bis(imidazol-1-yl)terephthalic Acid Ligand: Structural Diversities, Luminescence, and Magnetic Properties
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On the basis of the designed bifunctional 1,4-bis(imidazol-1-yl)terephthalic acid (H2BTA) ligand, a series of three-dimensional lanthanide coordination polymers, namely, [La2(BTA)1.5(ox)1.5(H2O)3]n (1), [Nd(BTA)(ox)0.5(H2O)]n (2), {[Ln(HBTA)(ox)(H2O)]·xH2O}n (Ln = Pr for 3 (x = 0), Sm for 4 (x = 0), Dy for 5 (x = 1.5), and Eu for 6 (x = 1)), and [Ln(BTA)(SO4)0.5(H2O)]n (Ln = Eu for 7, and Tb for 8) were obtained with the help of oxalate or sulfate ions. On the basis of the binuclear La2 secondary building unit (SBUs), the framework of 1 displays an unprecedented (3,3,4,9)-connected net with the point symbol of (411.55.614.75.8)2(42.5)2(43)2(44.62). While in complex 2, the binuclear Nd2 SBUs are connected by the BTA2- ligands to generate an interestingly (4,10)-connected (412.516.612.75)(46)2 net. Complexes 3-6 are isomorphism and show a 2-fold interpenetrated 4-connected (66)-dia net. Complexes 7 and 8 are isomorphism and show a novel (4,5)-connected (44.62)(44.66) net. Photoluminescence investigations show that 2 is a good near-infrared luminescent material, and 4 is a rarely reported single component white light emitting material. Complexes 6 and 7 show typically red emission, while complex 8 shows typically green emission, which can be used as a red or green emitting phosphor. Moreover, the luminescent lifetimes and quantum yields of the titled complexes were investigated. The magnetic susceptibility data of 2 indicated there are antiferromagnetic interactions between the NdIII ions.
- Zhang, Xiu-Tang,Fan, Li-Ming,Fan, Wei-Liu,Li, Bin,Liu, Guang-Zeng,Liu, Xin-Zheng,Zhao, Xian
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- Rational design, facile synthesis, and linear/nonlinear optical properties of novel two-photon absorption stilbene derivatives with different configurations
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Four novel two-photon absorption compounds (1MOBI, 2MOHA, 3BrBI, and 4BrHA), which have assembled stilbene π-bridge, different electron acceptors and donors, were synthesized conveniently via the one-step Horner-Wadsworth-Emmons reaction. Their configurations are A-π-D-π-A, D′-π-D-π-D′, A′-π-A-π-A′, and D-π-A-π-D, respectively. Their linear and nonlinear optical properties including linear absorption, one-photon excited fluorescence, two-photon absorption, and two-photon excited fluorescence, were systematically investigated in various solvents. The results demonstrate that the compounds with dihexylamino donors exhibit good optical properties. 2MOHA and 4BrHA exhibit large two-photon absorption cross-sections (2183 and 1737 GM) in DMF, which are larger than those of many known stilbene derivatives. The relationships between the structures and the optical properties were studied aided with the time-dependent density functional theory calculations.
- Cai, Zhi-Bin,Dai, Huan,Li, Sheng-Li,Lou, Qiao-Xian,Tian, Yu-Peng
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- Solid state multicolor emission in substitutional solid solutions of metal-organic frameworks
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Preparing crystalline materials that produce tunable organic-based multicolor emission is a challenge due to the inherent inability to control the packing of organic molecules in the solid state. Utilizing multivariate, high-symmetry metal-organic frameworks, MOFs, as matrices for organic-based substitutional solid solutions allows for the incorporation of multiple fluorophores with different emission profiles into a single material. By combining nonfluorescent links with dilute mixtures of red, green, and blue fluorescent links, we prepared zirconia-Type MOFs and found that the bulk materials exhibit features of solution-like fluorescence. Our study found that MOFs with a fluorophore link concentration of around 1 mol % exhibit fluorescence with decreased inner filtering, demonstrated by changes in spectral profiles, increased quantum yields, and lifetime dynamics expected for excited-state proton-Transfer emitters. Our findings enabled us to prepare organic-based substitutional solid solutions with tunable chromaticity regulated only by the initial amounts of fluorophores. These materials emit multicolor and white light with high quantum yields (-2-14%), high color-rendering indices (>93), long shelf life, and superb hydrolytic stability at ambient conditions.
- Newsome, Wesley J.,Ayad, Suliman,Cordova, Jesus,Reinheimer, Eric W.,Campiglia, Andres D.,Harper, James K.,Hanson, Kenneth,Uribe-Romo, Fernando J.
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- An N-heterocyclic carbene-functionalised covalent organic framework with atomically dispersed palladium for coupling reactions under mild conditions
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Covalent organic frameworks (COFs) are a new class of crystalline porous materials that could function as excellent scaffolds for heterogeneous catalysts. Herein, we report a functionalised COF (COF-NHC) using N-heterocyclic carbene (NHC) as a monomer building block via a facile ionothermal strategy. The simple and easily prepared imine-linked COF-NHC possessed two coordination sites (NHC and amine), which could fix the active component (Pd) tightly in COF, leading to atomically dispersed Pd in a heterogeneous catalyst. The as-prepared Pd@COF-NHC showed high stability in the Suzuki-Miyaura coupling reaction of arylboronic acids and aryl halides in aqueous media at room temperature, and could be easily recycled and reused multiple times without the loss of catalytic activity. Moreover, C-C coupling reactions could be accomplished using triarylbismuth reagents in ethanol aqueous solutions with high yields.
- Yang, Junjuan,Wu, Yuanyuan,Wu, Xiaowei,Liu, Wenjing,Wang, Yaofang,Wang, Junwen
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- Open-Chain Crown-Ether-Derived Two-Photon Fluorescence Probe for Real-Time Dynamic Biopsy of Mercury Ions
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A novel two-photon fluorescence probe for Hg2+ derived from bis(styryl)terephthalonitrile, as a two-photon fluorophore, and bis[2-(2-hydroxyethyl sulfanyl) ethyl]amino group (ionophore), as a novel Hg2+ ligand, was developed. The probe possesses small molecule size, large two-photon absorption cross-section (1067 GM) in H2O, non-cytotoxic effect, long wavelength emission at 588nm, large Stokes shift (121nm), excellent photostability, high water solubility, good cell permeability, and pH insensitivity in the biologically relevant range. The probe can selectively detect Hg2+ ions in live cells and living tissues without interference from other metal ions and the membrane-bound probes, and its quenching constant is 8.73×105 M-1.
- Huang, Chibao,Zhang, Daohai,Qu, Junle,Liu, Xiaonan,Zhao, Guanglian,Yuan, Tingxiang,Liu, Yang
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- A two-photon fluorescent lipid raft probe derived from dicyanostilbene and similar to cholesterol’s structure
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Lipid raft is a microdomain being rich in cholesterol and sphingolipid and closely related to neurodegenerative diseases such as Alzheimer’s disease and prion disease. Hence the study on the physiological mechanism of lipid raft is helpful to reveal its biological role and its correlations with diseases. Two-photon fluorescence probe for lipid raft is a sharp tool to achieve this goal. A dicyanocarbazolylstilbene-derived two-photon fluorescence probe for lipid raft (DLR) was developed. Both DLR and lipid raft belong to D-π-A (donor-π-acceptor; π: C = C) type rigid planar molecule, and contain four fused carbon rings (one five-membered ring and three six-membered ring), and bear a long carbon chain (C8H17). The excellent comparability between the rigid plane of the probe molecule and the rigid lipid raft could significantly enhance the specific affinity to lipid rafts. DLR’s maximum emission wavelength increased with medium polarity while its fluorescence intensity (FI) augmented with viscosity, and FI in DPPC (dipalmitoylphosphatidylcholine) was 20 times higher than that in DOPC (dioleoylphosphatidylcholine). DLR’s fluorescence lifetime in DPPC was more than 2.2 times longer than that in DOPC. These indicate that DLR can distinguish DPPC from DOPC. Φδs of DLR in DPPC and DOPC were 1350 GM and 67 GM, respectively. DLR can image lipid raft distribution in cells and tissues. Graphic abstract: [Figure not available: see fulltext.]
- Huang, Chibao,Yang, Yuzhu,Li, Youfeng,Lv, Guoling
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- Isoreticular Crystallization of Highly Porous Cubic Covalent Organic Cage Compounds**
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Modular frameworks featuring well-defined pore structures in microscale domains establish tailor-made porous materials. For open molecular solids however, maintaining long-range order after desolvation is inherently challenging, since packing is usually governed by only a few supramolecular interactions. Here we report on two series of nanocubes obtained by co-condensation of two different hexahydroxy tribenzotriquinacenes (TBTQs) and benzene-1,4-diboronic acids (BDBAs) with varying linear alkyl chains in 2,5-position. n-Butyl groups at the apical position of the TBTQ vertices yielded soluble model compounds, which were analyzed by mass spectrometry and NMR spectroscopy. In contrast, methyl-substituted cages spontaneously crystallized as isostructural and highly porous solids with BET surface areas and pore volumes of up to 3426 m2 g?1 and 1.84 cm3 g?1. Single crystal X-ray diffraction and sorption measurements revealed an intricate cubic arrangement of alternating micro- and mesopores in the range of 0.97–2.2 nm that are fine-tuned by the alkyl substituents at the BDBA linker.
- Bein, Thomas,Beuerle, Florian,Clever, Guido H.,Holstein, Julian J.,Ivanova, Svetlana,K?ster, Eva,Keller, Niklas
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- Synthesis and structure of the bimetallic organoantimony catalyst and its application in diastereoselective direct Mannich reaction as facile separation catalytic system
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A bimetallic organoantimony catalyst with four Lewis/Br?nsted acidic/basic sites assembled orderly was successfully synthesized and showed high catalytic efficiency. It has been applied in diastereoselective direct Mannich reaction by adding 0.1 mol% catalyst. This reaction presented unexpected facile separation ability from homogenous solution to heterogeneous solution.
- Tang, Niu,Song, Xingxing,Yang, Tianbao,Qiu, Renhua,Yin, Shuang-Feng
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- Tuning J-aggregate Formation and Emission Efficiency in Cationic Diazapentacenium Dyes
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Enhancement of the luminescence efficiency of two new diazapentacenium salts (D1 and D2) of more than 55 for D1 and 22 times for D2) in poor solvents, acetonitrile and/or dichloromethane, was observed and rationalized as formation of emissive J-aggregates. Both compounds displaying 4-n-decylphenyl substituents at the 7,14-carbons and phenyl (D1) or 2,6-difluorophenyl (D2) substituents at the quaternary nitrogen atoms in 5,12-positions have been synthetized in a two-step procedure involving a two-fold Buchwald-Hartwig-type CN cross-coupling and an electrophilic Friedel-Crafts-type cyclization. The optical properties of the dicationic diazapentacenium salts in various solvents and in thin films have been investigated by steady-state and time-resolved absorption and photoluminescence spectroscopies. In thin films and in good solvents, isolated molecules coexist with aggregates. Nonetheless, D1 is seven times more emissive than D2, reflecting a higher J-aggregate contribution in the former.
- Rodrigues, Ana Clara B.,Wetterling, Dario,Scherf, Ullrich,Seixas de Melo, J. Sérgio
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supporting information
p. 7826 - 7830
(2021/05/07)
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- Improved Photoreduction of CO2 with Water by Tuning the Valence Band of Covalent Organic Frameworks
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Porous covalent organic frameworks (COFs), as an emerging material, have the characteristics of high stability, large series of components, easy synthesis, modification, and adjustable amplitude. They have the potential to become good catalysts. Bromine, as a halogen, has attracted intensive interest for the modification of photocatalysts for photocatalytic reactions. It is feasible to enhance the activity and selectivity of the material by facile functionalization of the reticular parent structure′s electron-withdrawing groups. In addition, the conjugation effect of bromine, further delocalizing the electrons of the COF, is beneficial to the progress of many photocatalytic reactions. Reports on the modification of COFs by bromine functional groups to improve the catalytic performance have not been found so far. Here, TAPP [5,10,15,20-tetrakis(4-aminophenyl)porphyrin] and 2,5-dibromo-1,4-benzenedialdehyde instead of terephthalaldehyde were chosen to synthesize a porphyrin-based COF (TAPBB-COF) by the solvothermal method. As expected, the valence band (VB) of TAPBB-COF is thus adjusted to a more suitable position. Additionally, the CO production when using TAPBB-COF under full-wavelength light for 12 h was 295.2 μmol g?1, which was three times that of COF-366, and the new material has good recycling stability and selectivity (95.6 %). Theoretical calculations indicate that the nitrogen of the porphyrin ring and the Schiff base, and the bromine in TAPBB-COF contribute greatly to the activation of H2O and the conversion of CO2 in the photoreaction.
- Wang, Lu-jie,Wang, Rui-lei,Zhang, Xiao,Mu, Jing-lin,Zhou, Zi-yan,Su, Zhong-min
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p. 2973 - 2980
(2020/04/23)
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- MULTIVARIATE METAL-ORGANIC FRAMEWORKS FOR FINE-TUNING LIGHT EMISSION
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Multivariate metal-organic framework compositions and methods of producing multivariate metal-organic frameworks. The metal-organic framework including at least one light-emitting linker in an amount sufficient for the composition to produce broadband emission spectra in high efficiencies.
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Page/Page column 33-34
(2019/07/13)
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- Double-photon fluorescent probe used for temperature detection and derived from carbazole and preparation method of double-photon fluorescent probe
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The invention relates to the technical field of temperature probes, in particular to a double-photon fluorescent probe used for temperature detection and derived from carbazole and a preparation method of the double-photon fluorescent probe. The structural formula of the double-photon fluorescent probe is shown in the description. The fluorescence quantum yield of the probe is high, the detectionrange is wide, the application range of the double-photon fluorescent probe is greatly widened, and the detection reliability is improved.
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Paragraph 0024
(2018/04/03)
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- Preparation method of two-photon fluorescence pH probe and application in cell imaging thereof
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The invention belongs to the technical field of fine chemical engineering, and particularly relates to a preparation method of a two-photon fluorescence pH probe and application in cell imaging thereof. The probe is prepared by taking dicyan-biphenyl-ethylene as a matrix, and comprises carbazolyl, di-cyano and n-octyl. Because the molecular structure of the probe has a longer flexible chain, the lipophicity is stronger, the probe can penetrate a cell wall (or cell membrane) into a cell to stain the cell for detecting the pH in the cell; the molecular structure of the probe belongs to D-pi-A type molecules, the two-photon absorption cross section (delta) is improved, so that the probe has higher imaging definition and resolution; in addition, the probe has a large Stokes shift in the marking process, thereby greatly improving the imaging accuracy and precision; the fluorescence quantum yield (phi) of the probe in a solvent is higher, the two-photon emission cross section is larger, so that the higher the brightness of the imaging is, the clearer the image is, and the higher the resolution is.
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Paragraph 0041; 0044; 0045
(2018/09/12)
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- Double-cyano stilbene ethylene two-photon fluorescent solvent chromophore water-soluble probe and its synthetic method and application (by machine translation)
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The invention belongs to the technical field of fine chemicals, in particular to double-cyano stilbene ethylene two-photon fluorescent solvent chromophore water-soluble probe and its synthetic method and application, the probe in order to double-cyano stilbene (DCS) for the two-photon fluorescent matrix preparation. The probe molecules of small size, good solubility in water and is suitable for solvent polarity detection, in addition to the fluorescence intensity of the probe, two-photon absorption cross section of the insured with viscosity changes obviously, display a very wide range of solvent chromophore, large two-photon absorption cross section and ultra-large Stokes displacement, thereby greatly improving the detection sensitivity, imaging resolution, sensitivity and transverse and longitudinal resolution, and the accuracy of the test; cell microscopic imaging experiment to demonstrate that its in a cell or tissue has good color range and absorption effect, can be very good detection and reflect cell change in viscosity of the situation, and itself not toxic to the cells. In biological, in the medical field has great application value. (by machine translation)
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Paragraph 0037-0041
(2018/10/19)
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- Two-photon fluorescent sodium ion probe and its synthetic method and application (by machine translation)
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The invention belongs to the technical field of fine chemicals, in particular to a two-photon fluorescent sodium ion probe and its synthetic method and application, the probe in order to double-cyano stilbene is two-photon fluorescent matrix preparation. The probe molecules of small volume, to the sodium ion has very good selectivity, but zinc, potassium, calcium, magnesium, manganese, mercury and sodium ion other than the ion detection without interference, can detect micromolar concentration of the sodium ion. After the probe molecule complex sodium fluorescence intensity drop, sodium ion content can be two-photon fluorescence detection. Two-photon fluorescence microscopy imaging experiment shows the type of probe to the fibroblast like cells or tissue permeability, itself is not toxic to the cells, is especially suitable for the cell in the sodium ion concentration change and mercury ion distribution detection, in biological, in the medical field has great application value. (by machine translation)
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Paragraph 0011; 0042; 0045; 0047-0048
(2018/09/14)
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- Regioselective Halogenation of Arenes and Heterocycles in Hexafluoroisopropanol
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Regioselective halogenation of arenes and heterocycles with N-halosuccinimides in fluorinated alcohols is disclosed. Under mild condition reactions, a wide diversity of halogenated arenes are obtained in good yields with high regioselectivity. Additionally, the versatility of the method is demonstrated by the development of one-pot sequential halogenation and halogenation-Suzuki cross-coupling reactions.
- Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
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p. 930 - 938
(2018/01/28)
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- Cell in the mercury ion detection and for developing diphenyl ethylene bis-cyano benzene pair photon fluorescent probe
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The invention relates to a diphenylethene group dual cyano benzene two-photon fluorescence probe for detecting and displaying intracellular Hg ions, and the probe is prepared by performing nucleophilic substitution on mercaptoethanol and 2,5-di(4-[di(2-chloroethyl)amino]styryl)para-phthalonitrile. Laser excitation of 810nm can avoid photoinduced toxicity of cells. In a range of pH being 4.5-13, the probe has good selectivity on the Hg ions, and Na, K, Ca, Mg and Mn ions have no interference with detection, and the Hg ions of micro molarity can be detected. Fluorescence intensity is reduced after complexing of probe molecules and the Hg ions, and the content of the Hg ions can be subjected to two-photon fluorescence detection. A two-photon fluorescence microimaging experiment shows that the probe has good permeability on fibroblasts and other cells, has no toxic or side effects on the cells and is particularly suitable for the detection of intracellular Hg ion concentration change and Hg ion distribution.
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Paragraph 0037; 0038
(2017/08/25)
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- Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
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We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
- Bose, Anima,Mal, Prasenjit
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supporting information
p. 2154 - 2156
(2015/03/18)
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- Synthesis of dilactone bridged terphenyls with crankshaft architectures
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Three highly fluorescent dilactone bridged terphenyls with crankshaft architectures have been synthesized. This general class of compounds is relatively unexplored. These compounds have been characterized by fluorescence and UV-vis spectroscopy. For all three compounds, a direct correlation between the rigidity of the terphenyl system and the strength of absorption and emission of light has been observed. Preliminary studies have indicated that compounds with this architecture have the potential to be useful as pH-driven molecular switches and/or sensors with instant fluorescence attenuation at high pH values.
- Dressler, Justin J.,Miller, Sarah A.,Meeuwsen, Brian T.,Riel, Asia Marie S.,Dahl, Bart J.
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supporting information
p. 283 - 292
(2015/02/02)
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- Strong solid emission and mechanofluorochromism of carbazole-based terephthalate derivatives adjusted by alkyl chains
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Three 2,5-dialkylcarbazole-substituted terephthalate derivatives, in which carbazole and ethoxylcarbonyl groups are used as electron-donating and -accepting moieties, respectively, were synthesized. Owing to the presence of steric hindrance between ethoxylcarbonyl and carbazole groups, three compounds show intense blue fluorescence in both solution and the solid state. The fluorescence quantum yields of compounds with octyl and hexadecyl groups in the solid state exceed 95%. Single-crystal structures of three compounds were obtained and used to interpret the strong emission in the solid state. More interestingly, three compounds exhibited alkyl length-dependent mechanofluorochromism. The compound with ethyl groups exhibited the largest spectral shift under force stimuli, but that with a hexadecyl moiety did not change its emission color after grinding. Because of strong fluorescence in solution and the solid state, we believe that they can be used as luminescent materials and sensors. This journal is
- Xue, Pengchong,Sun, Jiabao,Chen, Peng,Gong, Peng,Yao, Boqi,Zhang, Zhenqi,Qian, Chong,Lu, Ran
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p. 4086 - 4092
(2015/04/27)
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- Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
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We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
- Bose, Anima,Mal, Prasenjit
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supporting information
p. 2154 - 2156
(2014/04/03)
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- Heptagon-embedded pentacene: Synthesis, structures, and thin-film transistors of dibenzo[d,d′]benzo[1,2-a:4,5-a′]dicycloheptenes
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This study presents a new class of conjugated polycyclic molecules that contain seven-membered rings, detailing their synthesis, crystal structures and semiconductor properties. These molecules have a nearly flat C 6-C7-C6-C7-C6 polycyclic framework with a p-quinodimethane core. With field-effect mobilities of up to 0.76cm2V-1s-1 as measured from solution-processed thin-film transistors, these molecules are alternatives to the well-studied pentacene analogues for applications in organic electronic devices. All sixes and sevens: A new class of conjugated polycyclic molecules have a nearly flat C6-C7-C6-C 7-C6 polycyclic framework with a p-quinodimethane core. With a field-effect mobility of up to 0.76cm2V-1s -1 as measured from solution-processed thin-film transistors, these molecules are alternatives to the pentacene analogues for application in organic electronic devices.
- Yang, Xuejin,Liu, Danqing,Miao, Qian
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supporting information
p. 6786 - 6790
(2014/07/08)
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- On the ionizing properties of supercritical carbon dioxide: Uncatalyzed electrophilic bromination of aromatics
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Supercritical carbon dioxide (scCO2), a solvent with a zero dipole moment, low dielectric constant, and no hydrogen bonding behavior, is a suitable medium to perform the uncatalyzed electrophilic bromination of weakly activated aromatics with no interference of radical pathways. The ability of scCO2 to promote these reactions matches those of strongly ionizing solvents such as aqueous acetic and trifluoroacetic acids. Conversely, carbon tetrachloride, with similar polarity parameters to scCO2, leads exclusively to side chain functionalization. The strong quadrupole moment, and the acidic, but non basic, Lewis character of carbon dioxide, are proposed as key factors for the singular performance of scCO2 in reactions involving highly polar and ionic intermediates.
- Delgado-Abad, Thais,Martnez-Ferrer, Jaime,Reig-Lpez, Javier,Mello, Rossella,Acerete, Rafael,Asensio, Gregorio,Gonzlez-Nez, Mara Elena
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p. 51016 - 51021
(2015/01/16)
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- New side groups-tuned triphenylamine-based chromophores: Synthesis, morphology, photophysical properties and electronic structures
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A new series of crossing symmetric triphenylamine-based chromophores with different side groups were synthesized. Their morphological structure, thermal stabilities and photo-physics were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA), UV-vis spectrophotometer and fluorescent photometer. The results indicated that these compounds emitted green fluorescence with a quantum yield ranging from 0.34 to 0.80 and a lifetime of 0.89 to 1.34 ns. Meanwhile, these compounds with crystal character or amorphous phase exhibited relatively high decomposition and glass transition temperatures. Their electrochemical behaviors and electronic structures were investigated in detail by cyclic voltammetry (CV), and further confirmed by theoretical calculation. The introduced side groups lowered the electron density of the conjugated system, resulting in a significant decrease of LUMO energy level. In a word, it suggested that the optical properties were regulated by the electronics structures with the different effect of the side groups on the LUMO.
- Liu, Pei,Zhang, Peng,Cao, Dongliang,Gan, Lihua,Li, Yuanfang
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p. 151 - 158
(2013/10/01)
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- Dicyanostilbene-derived two-photon fluorescence probe for free zinc ions in live cells and tissues with a large two-photon action cross section
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A novel two-photon fluorescence probe for Zn2+ derived from dicyanostilbene as a two-photon fluorophore and 4-(pyridine-2-ylmethyl) piperazine as a novel Zn2+ ligand was developed. The probe shows a 72.5-fold fluorescence enhancement in response to Zn2+, a large two-photon action cross-section (580 GM), a noncytotoxic effect, and pH insensitivity in the biologically relevant range, and its dissociation constant (KdTP) is 0.52 ± 0.01 μM. The probe can selectively detect free Zn2+ ions in live cells for 1500 s or so and in living tissues at a depth of 80-150 μm without interference from other metal ions and the membrane-bound probes.
- Huang, Chibao,Qu, Junle,Qi, Jing,Yan, Meng,Xu, Gaixia
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scheme or table
p. 1462 - 1465
(2011/06/21)
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- New photosensitizer with phenylenebisthiophene central unit and cyanovinylene 4-nitrophenyl terminal units for dye-sensitized solar cells
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A new low band gap photosensitizer, D, which contains 2,2′-(1,4- phenylene) bisthiophene central unit and cyanovinylene 4-nitrophenyl terminal units at both sides was synthesized. The two carboxyls attached to the 2,5-positions of the phenylene ring act as anchoring groups. Dye D was soluble in common organic solvents, showed long-wavelength absorption maximum at 620-636 nm and optical band gap of 1.72 eV. The electrochemical parameters, i.e. the highest occupied molecular orbital (HOMO) (-5.1 eV) and the lowest unoccupied molecular orbital (LUMO) (-3.3 eV) energy levels of D show that this dye is suitable as molecular sensitizer. The quasi solid state dye-sensitized solar cell (DSSC) based on D shows a short circuit current (Jsc) of 9.95 mA/cm2, an open circuit voltage (Voc) of 0.70 V, and a fill factor (FF) of 0.64 corresponding to an overall power conversion efficiency (PCE) of 4.40% under 100 mW/cm2 irradiation. The overall PCE has been further improved to 5.52% when diphenylphosphinic acid (DPPA) coadsorbent is incorporated into the D solution. This increased PCE has been attributed to the enhancement in the electron lifetime and reduced recombination of injected electrons with the iodide ions present in the electrolyte with the use of DPPA as coadsorbant. The electrochemical impedance spectroscopy (EIS) results indicated that the augment ascribes to inhibited interfacial charge recombination between the conduction band electrons and the tri-iodide ions in the electrolyte.
- Mikroyannidis,Suresh,Roy,Sharma
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scheme or table
p. 5616 - 5623
(2011/06/26)
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- Study of the interaction between 2,5-di-[2-(4-hydroxy-phenyl)ethylene]- terephthalonitril and bovine serum albumin by fluorescence spectroscopy
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A new compound, 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitrile (DHPEPN), was synthesized. The interaction between bovine serum albumin (BSA) and DHPEPN in Tris-HCl buffer solution (pH 7.4) was investigated using fluorescence and UV-vis absorption spectroscopy. The mechanism of BSA fluorescence quenched by DHPEPN is discussed according to the Stern-Volmer equation. The binding constant and the thermodynamic parameters ΔH, ΔS, ΔG at different temperatures were calculated. The results indicate that the van der Waals interaction and hydrogen bonding play major roles in the binding process. The distance between BSA and DHPEPN is estimated to be 3.59 nm based on the Fo?rster resonance energy transfer theory. The spectral changes of synchronous fluorescence and three-dimensional fluorescence suggest that both of the microenvironment of DHPEPN and the conformation of BSA are changed during binding between DHPEPN and BSA.
- Zhang, Li-Na,Wu, Fang-Ying,Liu, Ai-Hong
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scheme or table
p. 97 - 103
(2011/06/27)
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- Dicyanostilbene-derived two-photon fluorescence dyes with large two-photon absorption cross sections
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Four dicyanostilbene-derived two-photon fluorescence (TPF) dyes were synthesized as the model compounds to systematically study the effect of the dicyano and the terminal substituent on the two-photon absorption (TPA). These four compounds (DSO, DCY, DTO and DPH) exhibit very large two-photon absorption cross sections (δ). DCY (A-π-A) with the terminal cyano group has especially high fluorescence quantum yield (0.71) and relatively large δ (1480 GM), while DPH (D-π-A) with the substitutedamino group at its terminus possesses the largest δ (2800 GM) and the longest emission wavelength (620 nm). The idealest terminal substituent should not be the alkoxy group but the substitutedamino group. This class of dicyanostilbene dyes possess small molecule size, large δ (830-2800 GM), long-wavelength emission (459-620 nm) and large Stokes shift (80-206 nm), and are ideal chromophores for TPF labels and probes.
- Huang, Chibao,Lin, Changhua,Ren, Anxiang,Yang, Nianfa
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scheme or table
p. 91 - 95
(2012/01/31)
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- Enhanced performance of bulk heterojunction solar cells using novel alternating phenylenevinylene copolymers of low band gap with cyanovinylene 4-nitrophenyls
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Two novel low band gap soluble copolymers, P1 and P2, were synthesized and characterized. P1 consisted of alternating dihexyloxyphenylene and α-[[4-(diphenylamino) phenyl]methylene]-4-nitro-ben-zeneacetonitrile. P2 consisted of alternating dihexyloxyphenylene and α,α'-[(1,4- phenylene)dimethy-lidyne]bis(αZ,α'Z)-4-nitrobenzeneacetonitrile. These copolymers showed broad absorption curves with long-wavelength absorption maximum around 620 nm and optical band of 1.68 and 1.64 eV for P1 and P2, respectively. Both P1 and P2 were blended with PCBM to study the photovoltaic response of bulk heterojunction (BHJ) solar cells. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of both P1 and P2 are well aligned with those of PCBM acceptor. This allows efficient photoinduced charge transfer and high open circuit voltage, leading to an overall power conversion efficiency (PCE) of 3.15% and 2.60% for the as cast P1:PCBM-and P2:PCBM-based devices, respectively. The PCE of the devices has been further improved up to 4.06% and 3.35% for the devices based on thermally annealed P1:PCBM and P2:PCBM blends, respectively.
- Mikroyannidis,Kabanakis,Balraju,Sharma
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scheme or table
p. 5544 - 5553
(2011/10/30)
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- Synthesis and structures of novel luminescent bent acenedithiophenes
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1,4-Dithienyl-2,5-divinylbenzenes are readily available compounds that undergo oxidative photocyclization to afford bent anthradithiophenes (BADTs). The new parent and didodecyl-functionalized derivatives have been structurally characterized, and their absorption and emission spectra are reported.
- Pietrangelo, Agostino,MacLachlan, Mark J.,Wolf, Michael O.,Patrick, Brian O.
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p. 3571 - 3573
(2008/02/11)
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- Polycyclic aromatic hydrocarbons by ring-closing metathesis
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A strategy for the synthesis of polycyclic aromatic hydrocarbons (PAHs) by the ring-closing olefin metathesis (RCM) of pendant olefins on a phenylene backbone has been developed. RCM of 2,4′,6′,2″-tetravinyl-[1, 1′;3′,1″]terphenyl and 2,2′,5′,2″- tetravinyl-[1,1′;4′,1′]terphenyl affords in high yield the isomeric [a,j] and [a,h] dibenzanthracenes, respectively. In contrast with other intramolecular annulation methods, such as Friedel-Crafts acylations, this reaction is completely regioselective. Since RCM is reversible and PAHs are often thermodynamic sinks, this strategy is an effective and general method for the preparation of PAHs. Density functional theory calculations support these results. Carbon disulfide is a suitable solvent for these reactions.
- Bonifacio, Margel C.,Robertson, Charles R.,Jung, Jun-Young,King, Benjamin T.
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p. 8522 - 8526
(2007/10/03)
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- Experimental and theoretical studies of 2,5-diphenyl-1,4-distyrylbenzenes with all-cis- And all-trans double bonds: Chemical structure determination and optical properties
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2,5-Diphenyl-1,4-distyrylbenzene (DPDSB) with all-cis (cw-DPDSB) and all-trans double bonds (trans-DPDSB) were synthesized by Wittig reaction and the differences in structural and optical properties between the cis- and trans-isomers are discussed in detail. Both compounds were fully characterized by NMR spectroscopy, FT-IR spectroscopy, x-ray crystallography, differential scanning calorimetry (DSC) and electrochemical methods. X-ray analysis and molecular simulation revealed that the structure of cis-DPDSB obviously deviates from planarity along both the distyrylbenzene and terphenyl directions, and less intermolecular interaction exists in crystal. The cisisomer shows a large blue shift in the absorption spectrum in comparison with that of the trans-isomer, and cyclic voltammetric measurements give bandgaps of 3.16 and 2.97 eV for cis- and trans-DPDSB, respectively. Both compounds show unusually strong blue fluorescence in the solid state, probably due to the weak intermolecular interaction existing in both isomers owing to the large steric hindrance induced by the substituted phenyl groups. DSC experiments determined that both isomers have excellent thermal stability, which indicates that they can be used as active layers to make stable devices. Quantum chemical calculations for the frontier molecular orbital and the cation and anion properties reveal that the HOMO and LUMO are completely localized in the distyrylbenzene direction and the distyrylbenzene segment has more sensitive electroactivity than the terphenyl segment whether it is cis- or trans-DPDSB. Copyright
- Xie, Zengqi,Yang, Bing,Liu, Linlin,Li, Mao,Lin, Dong,Ma, Yuguang,Cheng, Gang,Liu, Shiyong
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p. 962 - 973
(2007/10/03)
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- Synthesis of comb-like polyarylenes by oxidattve polymerization of a well-defined polystyrene macromonomer with naphthalene moieties
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Synthesis of a polystyrene (PSt) grafted polyarylene with naphthalene groups in the main chain is described. 1,4-Dibromo-2,5-bis(bromomethyl)benzene was used as initiator in ATRP of styrene using CuBr/2,2′-bipyridine as catalyst and polymeric precursor, that possesses a designed molecular weight with a narrow molecular weight distribution and two bromine atoms directly linked to a central benzene ring, was obtained. The Suzuki coupling between the bromine functionalized PSt and 1-naphihyl boronic acid furnished a macromonomer with naphthyl moieties as oxidable groups. Following chemical oxidative polymerization in the presence of anhydrous FeCl3, a soluble and processable polyarylene with PSt side chains was synthesized. The starting macromonomers as well as the final polyarylenes were analyzed by GPC and spectral methods (1H-NMR, IR and UV-vis). The thermal behaviour of the polymers was studied by differential scanning calorimetry (DSC) and thermogravimetrical analysis (TGA).
- Mercore, Viorela-Mihaela,Cianga, Ioan,Grigoras, Mircea,Yagci, Yusuf
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p. 607 - 616
(2007/10/03)
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- A simple and improved procedure for selective ring bromination of alkyl-substituted aromatic hydrocarbons on the surface of alumina
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Highly selective ring bromination of alkyl-substituted aromatic hydrocarbons has been achieved using molecular bromine adsorbed on the surface of alumina without any solvent.
- Ranu,Sarkar,Chakraborty
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p. 1095 - 1099
(2007/10/02)
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- CATALYTIC AND STOICHIOMETRIC BROMINATION OF AROMATIC COMPOUNDS IN AQUEOUS TRIFLUOROACETIC ACID IN THE PRESENCE OF NITROGEN-CONTAINING OXIDIZING AGENTS
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The mono- and polybromination of benzene, halogenobenzenes, toluene, p-xylene, anisole, biphenyl, benzotrifluoride, benzoic acid, p-nitro- and p-carboxytoluene, p-methoxybenzonitrile, tetralin, and naphtalene were studied in trifluoroacetic acid and its aqueous solutions in systems containing stoichiometric amounts of bromine or alkali-metal bromide and stoichiometric or catalytic (in the presence of oxygen or air) amounts of nitrogen-containing oxidizing agent (nitrogen(IV) oxide, alkali-metal nitrate or nitrite).It is suggested that the brominating agent under the investigated conditions is nitryl bromide NO2Br.Under the conditions of catalytic bromination anthracene is oxidized to anthraquinone with a preparative yield.
- Cheprakov, A. V.,Makhon'kov, D. I.,Rodkin, M. A.,Beletskaya, I. P.
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p. 217 - 223
(2007/10/02)
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- ACCES AUX DINITRO-2,4 DIARYLAMINES PAR SUBSTITUTION NUCLEOPHILE SNAr-LIMITES DE LA REACTION ET APPLICATION A LA SYNTHESE DE CYANOCARBAZOLES
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3-Cyanocarbazoles, key-intermediates in the total synthesis of pyrido carbazoles, have been obtained starting from easily available materials and involving the cyclization of diarylamines.The first step of the preparation consists in a SNAr reaction between a para substituted aniline and a chloro- (or bromo)-dinitrobenzene.This nucleophilic substitution has been found to be hindered by the steric effect of a methyl group, explained in terms of inhibition of resonance and confirmed by X-ray determination.
- Henichart, J. P.,Bernier J. L.,Vaccher, C.,Houssin, R.,Warin, V.,Baert, F.
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p. 3535 - 3542
(2007/10/02)
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- Process for preparation of 2,5-dibromo-p-xylene
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Selective bromination process for 2,5-dibromo-p-xylene which comprises bromination of p-xylene using approximately stoichiometric amounts of bromine and a hydrated iron containing bromination catalyst to give selectively high yields of substantially pure 2,5-dibromo-p-xylene.
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