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Three-photon absorption (3PA) of a push-pull chromophore, 2-(3-cyano-(3-(4-(dimethylamino)styryl)-5, 5-dimethylcyclohex- 2-enylidene)methyl)-5, 5-dimethylfuran-2-ylidene) malononitrile (CFM) including TCF group was measured by the nonlinear transmission method using a femto-second Ti:sapphire oscillator-amplifier laser system. Its three-photon absorption cross-sections at 1300 nm were 36.8×10−79 cm6s2 in the solution of DMF and 12.3×10−79 cm6s2 in the solution of CH2Cl2, respectively. The large values were got by experiments in this paper, which is a new exploration for these kinds of materials. The molecule has the potential application foreground of 3PA areas and optical power limiting.
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A homologous series of heterocycles, 6-methyl-2-(4-alkoxybenzylidenamino)benzothiazoles, were synthesized and characterized using FT-IR, 1H and 13C NMR and mass spectrometric analysis. Enantiotropic nematic phase was observed for shorter members. Smectic A phase only emerged from octyloxy derivative onwards. The terminal methyl group at the benzothiazole fragment and the Schiff base linkage influenced the mesomorphic behavior of the present series.
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Bromination is used as a strategy to improve biological activity in medicinal chemistry. In order to study on the structure-activity relationships of the novel acetylcholinesterase inhibitors with 7H-thiazolo[3, 2-b]-1, 2, 4-triazin-7-one scaffold, based on our previous work and molecular modeling, a series of novel 3-aryl-6-(bromoarylmethyl)-7H-thiazolo[3, 2-b]-1, 2, 4- triazin-7-one derivatives were designed by molecular docking, synthesized and characterized by mass spectra, infrared spectra, proton NMR and elemental analyses. The study of AChE inhibitory activity was carried out using the Ellman colorimetric assay with huperzine-A as the positive control. Most of all target compounds exhibited more than 45 % inhibition at 10μmol/L. The preliminary structure-activity relationship was the bromine atoms and the hydroxyl group at the phenyl ring at the C6 position of the parent nucleus played significant roles in the AChE inhibitory activity of the target compounds.
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This article describes the preparation and liquid crystalline properties of a new homologous series of 4-(4-bromopropyloxy)-4′-(4-alkyloxybenzylidene)anilines in which the phenyl ring is armed by a bromopropyloxy chain. The thermal behavior and mesomorphic properties of the synthesized compounds were studied with particular attention given to the correlation between their phase transition temperatures and anisotropic change influenced by molecular structure. All the members displayed enantiotropic smectic phase except for the homologue with the longest alkyloxy chain (R=C18H37), exhibiting only monotropic characteristic. The presence of bromine atom from the propyloxy side chain is found to be capable of altering and influencing the mesomorphic properties.
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Selective hydrogenation of α, β-unsaturated aldehydes with modified Pd/C catalyst was developed. The reduction of C=O bond could be efficiently inhibited by the addition of carbonates, and high selectivity to the corresponding saturated aldehydes was achieved under mild conditions. This protocol provides an alternative for efficient preparation of saturated aldehydes.
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The reaction of ethyl α-bromocinnamates with tetrabutyl ammonium fluoride (TBAF) was influenced largely by the position of the substituent at the phenyl ring. While the substrates without an ortho substituent at the phenyl ring were transformed to the corresponding β-fluoro ethyl cinnamates under the reaction conditions, the presence of an ortho substituent only resulted in the formation of ethyl 3-phenylpropiolate derivatives. The reaction of ethyl 2-bromo-3-(4-methoxyphenyl) acrylate also failed to deliver the hydrofluorination product due to the electron-donating effect of the methoxy group.
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An efficient and eco-friendly protocol for the chemoselective N-benzyloxycarbonylation of amines was described. The reaction of amines with benzyl chloroformate (Cbz-Cl) in the presence of PEG-600 at room temperature afforded the corresponding N-Cbz derivatives in excellent yields. The method is applicable to the N-Cbz protection of aliphatic (acyclic and cyclic) and aromatic amines.
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Three novel flame retardants containing both phosphorus and silicon elements in their structures, including [(1, 1, 3, 3-tetramethyl-1, 3-disiloxanediyl)di-2, 1-ethanediyl]bis(diphenylphosphine oxide) (FR-1), [(2, 4, 6, 8-tetramethylcyclotetra- siloxane-2, 4, 6, 8-tetrayl)tetra-2, 1-ethanediyl]tetrakis[diphenylphosphine oxide] (FR-2) and 1, 3, 5, 7, 9, 11, 13, 15-octakis(di- phenylphosphine oxide-2, 1-ethanediyl)pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane (FR-3) were synthesized by a convenient pathway from the reaction of diphenylphosphine oxide (DPPO) and vinyl-terminated siloxanes under the catalysis of triethylborane. The chemical structures of the target compounds were confirmed by nuclear magnetic resonance (1H NMR, 13C NMR, 29Si NMR and 31P NMR), matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) and Flourier transform infrared (FT IR) measurements. Thermogravimetric analysis (TGA) results indicated that the new flame retardants possessed good thermal stability both in nitrogen and in air. FR-3 containing polyhedral oligosilsesquioxanes (POSS) moiety exhibited the best thermal properties with a 10 % weight loss temperature > 400 oC and a residual weight ratio > 39 % at 700 °C.
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Poly(4-vinyl pyridine) supported nanoparticles of copper(I) iodide is reported as a green and recyclable catalyst for the regioselective synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from benzyl halides, sodium azide and alkynes terminal in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any losing of its efficiency.
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A new type of ionic liquid supported selenium reagents were synthesized and found to be an excellent catalyst in the oxidation of alcohols to aldehydes and ketones in the presence of 30% H2O2. The predictable solubility of ionic liquids allows an easy separation of the oxidation products from the reaction mixture. Furthermore, the oxidation reaction can be carried out using an ionic liquid as the solvent, and the ionic liquid-supported selenium reagents can be recycled and used for four times with a little decrease in catalytic performance.
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A direct decarbonation route without obvious morphology damage was developed for large micrometer-scale layered double hydroxides (LDHs). First, we synthesized pure, hexagonal-shaped LDHs with lateral dimension of micrometer-size by the recently-reported urea hydrolysis method. Then, using HNO3-NaNO3 mixed solution, the obtained LDH with carbonate anions in the interlayer (LDH_CO3) was directly decarbonated to its nitrate form, LDH_NO3, its morphology and particle size were still unchanged. Compared with the recently-published two-step decarbonation method, the direct decarbonation reported herein is very convenient.
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A novel magnetic anion exchange resin NDM-1 was prepared through suspension polymerization and then functionalized with ammonolysis and alkylating agents. Its application for selective removal of nitrate was performed in comparison with MIEX®. The results demonstrated that NDM-1 achieved higher efficiency in nitrate removal than MIEX® did, with or without the existence of competing anion SO42− ascribed to its longer alkyl chains on exchange sites. Combined with the advantage of easy separation due to γ-Fe2O3 implanted, the magnetic anion exchange resin NDM-1 was considered to be superior to MIEX® for nitrate removal in practical application.
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A series of novel 1,3,4-thiadiazole derivatives based on benzisoselenazolone were synthesized and evaluated for their cytotoxicity in vitro against human liver cancer cell SSMC-7721, human breast cancer cell MCF-7 and human lung cancer cell A549 by CCK-8 assay. The results showed that compounds 7e, 7f, 7h, 7k, 7l and 7m displayed good cytotoxity against MCF-7 cell lines. Compound 7l exhibited the most potent antitumor activities among the tested compounds.
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A novel dimeric procyanidin glucoside, catechin 3-O-acetate-(4α→8)-catechin 3-O-acetate-3′-O-β-D-glucopyranoside (1), along with five flavonoids and one lignan were isolated from the aerial parts of Polygonum aviculare. Their structures were elucidated by spectroscopic analyses including 1D, 2D NMR, MS and CD methods.
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One new sesquiterpene lactone, 1α,8α,9α-trihydroxyeudesman-3(4),7(11)-dien-8β,12-olide (1) and two new phenylpropanoid- substituted catechin glycosides, glabraoside C (2) and glabraoside D (3) were isolated from the whole plant of Sarcandra glabra. Their structures were established by the analyses of spectral and chemical evidences.
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Two new triterpenoids, named as 2α, 3β, 23-trihydroxylurs-12, 20 (30)-dien-28-oic acid β-D-glucopyranoside (1), and 2α, 3β, 6β, 20β, 23, 30-hexahydroxyurs-12-en-28-oic acid (2), together with four known triterpenoids were isolated from the leaves of Psidium guajava L. Their structures were elucidated on the basis of mass and spectral evidence.
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We report a resonant method to measure the wall capacitance (Cw) and solution resistance (Rs) in a capacitively coupled contactless conductivity detector (C4D). Under the typical operating conditions in capillary electrophoresis (I.D. 50 ?m, O.D. 360 ?m, electrode length of 4 mm, electrode gap of 1 mm, frequency of 200 kHz ), the values of Cw measured in 1 and 20 mmol/L NaCl solutions are 2.8 and 32 fF, which are only 1.1 % and 12 % of prediction by the equation in references, respectively. The value of Rs is less than the prediction in solutions with κ<0.02 S/m. The response current of C4D is due to the change in Cw because the total impedance of a C4D is composed mainly by the impedance from Cw.
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An ion chromatography method has been proposed for the determination of three common inorganic anions (chloride, nitrate and sulfate) in anionic surfactants using a single pump system. The new system consists of an ion exclusion column, a concentrator column, and an anion exchange column connected in series via two 6-ports valves in a Dionex ICS-2000 ion chromatograph. The valves were switched several times for removing surfactants, concentrating and separating the three anions. The chromatographic conditions were optimized. Detection limits (S/N = 3) were in the range of 0.10–0.68 μg/L. The relative standard deviations (RSDs) of peak area were less than 4.6 %. The recoveries were in the range of 84.1–112.6 %.
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A simple, fast, sensitive, highly selective and eco-friendly analytical method for the determination of catecholamines in human urine by ion chromatography (IC) with chemiluminescence(CL) detection was described in this paper. Using 12 mmol/L H2SO4 without any organic additive as eluent, three catecholamines including epinephrine (EP), norepinephrine (NE) and dopamine (DA) were well separated on a cation-exchange column. The CL detection was based on the reaction of analytes with acidic potassium permanganate in the presence of formaldehyde as an enhancer. The absence of methanol and acetonitrile in eluent made the proposed method more sensitive and eco-friendly. Under the optimal conditions, the linear range of the proposed method was in the range of 0.02−0.5 µg/mL. The limit of detection (LOD) was in the range of 0.6 and 5.1 μg/L. The relative standard deviations (RSD) for 0.1μg/mL mixed standard solution were in the range of 0.8 %−1.9 % (n=11)．The method has been applied to the determination of catecholamines in human urine successfully. Excellent spiked recoveries were achieved for catecholamines ranged from 91.2 %−112.7 %.
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A method for rapid and simultaneous determination of imidazolium and pyridinium ionic liquid cations by ion-pair chromatography with ultraviolet detection was developed. Chromatographic separations were performed on a reversed-phase silica-based monolithic column using 1-heptanesulfonic acid sodium-acetonitrile as mobile phase. The effects of ion-pair reagent and acetonitrile concentration on retention of the cations were investigated. The retention times of the cations accord with carbon number rule. The method has been successfully applied to the determination of four ionic liquids synthesized by organic chemistry laboratory.
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Complex coacervation of whey protein (WP) with acacia gum (AG) was carried out in water with the presence of dodecyl acetate (DA), a component of insect sex pheromones, in order to obtain microcapsules with DA as the core material and WP-AG coacervate as the wall materials. Through variations in wall/core ratios, concentrations of the wall materials in capsule preparations, DA encapsulation was optimized, which showed a high DA encapsulation was achieved when coacervation was conducted at pH 3.5 with wall/core mass ratio at 3 combined with concentration of wall materials at 1.0 wt%. Morphology and the structure of DA loaded microcapsules were examined by scanning electron microscope, which showed the microcapsules were of core/shell structure with DA encapsulated in the inner of the microcapsules. DA release was examined and the behavior of the release was discussed.
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The Co3O4 nanowires have been successfully synthesized via modified template method. The as-prepared products have been characterized by EDS, TEM and HRTEM analysis. The magnetic behavior of it is investigated by a magnetic property measurement system. The nanowires exhibit some novel magnetic properties, which are different from its bulk material. The temperature dependence curves of magnetization in zero-field-cooling and field-cooling exhibit two peaks of antiferromagnetic at blocking temperature of ~23K and ~31K, respectively. The field dependent M(H) curves of the Co3O4 nanowires at T = 5 and 300 K both exhibit PM properties. Moreover, the diameter of nanowires is hence determined according to the finite size effect as approximately 7~11 nm, in consistent with the charaterizations by HRTEM.
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A novel fluorescent aqueous polyurethane emulsion DDAQ-TDI-PU was synthesized by blocking the anthraquinone moiety of 1,4-diamino-2,3-diphenoxyanthraquinone (DDAQ) into polyurethane chain using 2,4-tolylene diisocyanate (TDI), poly(propylene glycol) and 2,2-dimethylol propionic acid. The chain structure of DDAQ-TDI-PU was confirmed by means of Fourier transform infrared spectroscopy and UV-vis analysis. Comparing to the UV-vis spectrum of DDAQ, DDAQ-TDI-PU showed a hypsochromic shift from the absorption maxima of 518, 558, 609 nm to 510, 548, 586 nm, respectively. It was found that the fluorescence intensity of DDAQ-TDI-PU emulsion was enhanced greatly comparing with that of DDAQ. The fluorescence of DDAQ-TDI-PU was very stable not only for the long term storage but also for the fluorescence quencher.
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One novel organic-inorganic hybrid materials with 4, 4'-bipy ligands and copper chlorine coordination polymers as linkers, with new topology, {[CuI(4, 4'-bipy)]10Cl2(SiW12O40)2}•6H2O (1) (4, 4'-bipy = 4, 4'-bipyridine), has been hydrothermally synthesized. The single crystal X-ray structural analysis reveals that the structure of 1 is constructed from classical Keggin anions and [CuI(4, 4'-bipy)] cations into a novel, three-dimensional (3D) polyoxometalates based network. From the topological view, compound 1 is a novel (3.44.52.63)(32.44.56.69) topology. The electrochemical and photocatalysis properties of 1 have been investigated in details.
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A new base-aluminum-chloride-loaded fiber [PET-AA-NN-Al2(OH)nCl6-n] was prepared with polyethylene glycol terephthalate (PET) as adsorbent for fast removal of arsenic(V) from water. This new fibrous adsorbent was characterized by using SEM and CNMR spectroscopy. Adsorption kinetic curve indicated that this new fibrous adsorbent could fast remove arsenic (V) from water, and adsorption isotherm also indicated that PET-AA-NN-Al2(OH)nCl6-n had high equilibrium adsorption capacity for arsenic (V).
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A novel octupolar chromophore with 1, 3, 5-triazine as core, 2, 7-divinylene-9, 9-dimethylfluorene as extended π-conjugated bridge, triarylamine as the electron-donating end-groups was successfully synthesized and characterized. Their linear photophysical and two-photon absorption (TPA) properties were investigated by UV absorption, excited fluorescence (SPEF) spectra and nonlinear transmission method, respectively. The absorption cut-off of the chromophore is below 520 nm and it has stronger fluorescence emission in a nonpolar solvent. In addition, the chromophore exhibits larger TPA cross-section (226.0 GM) in the femtosecond regime at 800 nm.
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Poly(N-arylenebenzimidazole pyridine sulfone) (PNABIPS), has been prepared via the aromatic nucleophilic displacement reaction of 2, 6-bis(2-benzimidazoly)pyridine (BBP) with bis(4-fluorophenyl) sulfone. BBP was synthesized by reaction of 2, 6-pyridinedicarboxylic acid with 1, 2-phenylenediamine in polyphosphoric acid. The chemical structure of BBP was confirmed by FT-IR, HRMS, 1H NMR and 13C NMR. The characterization of the polymer was performed with FT-IR, 1H NMR, elemental analysis, GPC, XRD, DSC, TGA and solubility tests. The polymer was obtained in quantitative yield with Mn value 12600 and Mw value 28300, respectively. DSC and TGA measurements show that the glass transition temperature (Tg) is 312 °C and 5 % weight loss temperature is 434 °C in nitrogen and 545 °C in air, respectively. In addition, the novel polymer exhibits good solubility, which can be dissolved in common organic solvent at room temperature.
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To develop new tumor targeting macromolecular conjugates, poly(HPMA)-SD-APMA-DTPA (HPMA: N-(2-hydroxypropyl)- methacrylamide; APMA: N-(3-aminopropyl)methacrylamide; DTPA: diethylenetriaminepentaacetic acid; SD: sulfadiazine) was synthesized and characterized. The poly(HPMA)-SD-DTPA conjugates were radiolabeled with the radionuclide 99mTc and tested for uptake by cultured H22 cells in vitro. DTPA-99mTc (radiotracer 1) and poly(HPMA)-DTPA-99mTc (radiotracer 2) were also synthesized and characterized for comparison. The uptake of poly(HPMA)-SD-DTPA-99mTc (radiotracer 3, 34.76%) was significant higher than that of poly(HPMA)-DTPA-99mTc (16.40%), indicating that uptake of the poly(HPMA)-SD-DTPA-99mT was active binding. The uptake of poly(HPMA)-DTPA-99mTc was significant higher than that of DTPA-99mTc (2.98%), suggesting that uptake of the poly(HPMA)-DTPA-99mT was passive binding. The data suggest that the poly(HPMA)-SD-APMA-DTPA conjugates might be useful as tumor targeting macromolecular conjugates.
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PEGylated poly(2-(dimethylamino)ethyl methacrylate) with comb-like architecture was synthesized by two-step polymerization. First, poly(oligo(ethylene glycol) malicate) (POEGMA) bearing pendant hydroxyl groups was prepared by direct polycondensation of oligo(ethylene glycol) and malic acid in the presence of scandium triflate as chemoselective catalyst. Then the poly(2-(dimethylamino)ethyl methacrylate) side chains were grafted from the POEGMA backbone by atom transfer radical polymerization (ATRP) after the hydroxyl groups were modified into bromo-ester form, resulting in a PEGylated cationic copolymer with branched architecture.
