Search

Abstract: To evaluate the relative bioavailability of anethole trithione (ATT) from self-microemulsifying drug delivery system (SMEDDS) and tablet, a sensitive, accurate and reliable liquid chromatography method was developed and validated to determine ATT in rabbit plasma. Chromatographic separation was performed on a Diamonsil C18 column by using a mixture of methanol–water (90:10, v/v) delivered at a flow rate of 1.0ml/min. The wavelength was set at 348nm and mifepristone was used as the internal standard. A linear relationship for ATT was found in the range of 0.5–32ng/ml. The mean extraction recoveries of ATT determined over three concentrations were 84.7±5.8, 92.3±3.4 and 89.9±5.1%. After administration of SMEDDS and tablets to rabbits, significant differences were found in main pharmacokinetic parameters of T max, C max and AUC0–∞ between these two formulations, and a 2.5-fold enhancement of relative bioavailability of ATT was observed from the SMEDDS compared with tablets. [Copyright &y& Elsevier]

Abstract: A isocratic, selective, accurate and stability indicating HPLC method of analysis of nelfinavir mesylate both as a bulk drug and in formulations was developed and validated. A CN chromatographic column (250mm×4.6mm, 5μm) was used for the separation at 40°C. The mobile phase consisted of a mixture of acetonitrile (MeCN) and 25mM monobasic ammonium phosphate (containing 25mM triethylamine, pH 3.4 with phosphate acid) (40:60, v/v) was delivered at a flow rate of 1.0ml/min with detection at 210nm. The developed method was validated in terms of selectivity, linearity, limit of quantitation, precision, accuracy and solution stability. As the proposed LC method achieved satisfactory resolution between nelfinavir mesylate, its degradation products, intermediate product possibly present in nelfinavir drug substance and other impurities in the end product before refining in the final step of synthetic process, it can be employed as a stability indicating one, used for the synthetic process control and determination of nelfinavir mesylate in pharmaceutical preparations. [Copyright &y& Elsevier]

High speed countercurrent chromatography (HSCCC) was successfully applied to the preparative separation and purification of schisandrin and schisantherin from Schisandra chinensis ( Turcz ) Baill by microwave‐assisted extraction. The petroleum ether extract was separated with a two‐phase solvent system composed of n‐hexane‐ethyl acetate‐methanol‐water (22:8:20:20, v/v). The analysis of HPLC for each fraction from preparative HSCCC showed that the purity of schisandrin (16 mg) was over 98% and schisantherin (6 mg) was over 96% from the 100 mg of petroleum ether extract in a one‐step separation. [ABSTRACT FROM AUTHOR]

The article reports on a method of synthesis of bosutinib.

Although widely used in organic synthesis, pharmaceuticals and agrochemicals, thiophenol has brought about a series of ecological problems due to its high toxicity. Therefore, the development of efficient methods to discriminate thiophenols from aliphatic thiols is of great importance. In this work, a new reaction-based turn-on red fluorescence probe for the detection of thiophenols has been developed for the first time by employing dicyanomethylene-4H-pyran (DCM) as a fluorescence reporter and 2,4-dinitrobenzene-sulfonate (DNBS) as a recognition unit. The probe displayed a highly selective and sensitive (63 fold-fluorescence enhancement) response to thiophenols over aliphatic thiols. Additionally, the probe also exhibited a large Stokes shift (159 nm) and the detection limit reached as low as 8.3 nM. Moreover, this probe was also proved suitable for the quantification of thiophenol in real environmental water samples. [ABSTRACT FROM AUTHOR]

Abstract: To evaluate the bioavailability of puerarin sustained release tablet (SR-Tab.) and Yufengningxin tablet (YU-Tab.), a liquid chromatography method was developed and validated to determine puerarin in dog plasma. Chromatographic separation was performed on Diamonsil C18 column using a mixture of methanol–acetic acid–water (25:6:69, v/v/v) delivered at a flow rate of 1.0ml/min and detected by UV. 4-Hydroxybenzaldehyde was used as the internal standard. The linear range for puerarin was from 60 to 1800ng/ml (r =0.9991) with a limit of quantitation of 60ng/ml. Within-day accuracy and precision ranged from −3.0 to 2.2% and from 1.2 to 4.3%, between-day accuracy and precision ranged from −4.1 to 2.6% and from 1.3 to 5.7%, respectively. The mean extraction recoveries of puerarin determined over the three concentrations were (90.3±5.2)%, (95.7±1.4)% and (93.1±3.5)%. A significant difference was observed in main pharmacokinetic parameters of T max, C max and AUC0–∞ between puerarin SR-Tab. and YU-Tab. in dogs. The smoother plasma concentrations were obtained from SR-Tab. in dogs and the results were as expected. [Copyright &y& Elsevier]

Abstract: Two tetrathiafulvalene (TTF)-derived metallophthalocyanine complexes were synthesized. The structures of the target compounds and their intermediates have been characterized by NMR, MS, EA, UV–VIS and mp. The results of cyclic voltammetry indicated that the presence of zinc or magnesium phthalocyanine slightly affected the first oxidation of 4,5-ethylenedithiotetrathiafulvalene (EDT-TTF) unit. The EDT-TTF unit on the peripheral sites of the zinc phthalocyanine core could be more easily oxidized than the one on the same sites of the magnesium phthalocyanine core. [Copyright &y& Elsevier]

Abstract: High-speed counter-current chromatography (HSCCC) was successfully applied to the preparative separation and purification of deoxyschisandrin and γ-schisandrin from the crude petroleum ether extracts of Schisandra chinensis (Turcz.) Baill. The optimum solvent system composed of n-hexane–methanol–water (35:30:3, v/v) led to the successful preparation of deoxyschisandrin and γ-schisandrin. The analysis of HPLC for each peak fraction of preparative HSCCC showed that the purity of deoxyschisandrin (8mg) was over 98% and γ-schisandrin (12mg) was over 96% from 100mg of the crude petroleum ether extracts in one-step separation. [Copyright &y& Elsevier]

The polyfluoroalkyl-lactonization of 4-pentenoic acids having a substituent at the 2 or 3 position with the polyfluoroalkyl iodides initiated by sodium dithionite was realized in good yields. A new and efficient method for the synthesis of fluorine-containing γ-lactones is described. [Copyright &y& Elsevier]

Hydrazine, as a strong reducing agent, has been extensively used in many industrial manufactures. However, it is a potential human carcinogen and an environmental contaminant due to its high toxicity. Therefore, developing an ultrasensitive method for determining hydrazine in real water and biosystems is of great significance. Herein, based on coumarin dye, a turn-on fluorescent probe Cou-1-N 2 H 4 , which contains an acetyl group as the trigger unit and the fluorescence quencher, is developed. The probe can achieve a rapid (3min) and colorimetric sensing detection for hydrazine with an extremely low limit detection (11.9 nM or 0.38 ppb). More importantly, the practical utilities of probe have been successfully proved through quantitative N 2 H 4 detection in environmental water samples and bioimaging of N 2 H 4 in living cells. A coumarin-based fluorescent probe for ultrasensitive hydrazine sensing has been developed. The practical utilities of probe have been successfully proved through quantitative N 2 H 4 detection in environmental water samples and bioimaging of N 2 H 4 in living cells. Image 1 • Colorimetric and fluorescent two-output probe with dramatic responses to N 2 H 4. • An extremely low detection limit for N 2 H 4 determination. • Fluorescence bioimaging application in living HeLa cells. • Quantitative N 2 H 4 detection in water samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Construction of redox-responsive porphyrin-based amphiphilic copolymer nanoparticles. • High content disulfide units and porphyrin units contribute the alternating structure. • Appropriate and stable size enhances the cellular uptake efficiency of nanoparticles. • Redox-triggered rapid porphyrin release and enhancing 1O 2 generation in cancer cells. Abstract Stimulus-sensitive nanoparticles (NPs) have been established to widely adapt to remarkable abnormalities under the tumor microenvironment, which can observably enhance the therapeutic efficiency, improve the specific targeting ability and reduce the side effects. Photodynamic therapy (PDT) as a promising non-invasive and selective treatment for cancers through photodynamic reaction can profit from stimulus-sensitive NPs. Herein, a harmonious amphiphilic polymer (PEG- b -PTPPDS- b -PEG) with an extremely sensitive redox response is constructed via click chemistry between N 3 -TPPC6-N 3 , PEG-N 3 and alkynyl-containing disulfide ester for PDT. This polymer can be self-assembled into micelles with excellent stability, ultra-fast sensitivity of redox-triggered porphyrin release, and significant photodynamic anticancer performance. The redox-triggered dissociation of micelles and the release of porphyrin are much faster than common porphyrin-containing polymer. The bio-distribution and phototoxicity of micelles against A549 cells are measured and evaluated in vitro by flow cytometry, confocal scanning laser microscopy (CLSM) and MTT assay, respectively. The results reveal that PEG- b -PTPPDS- b -PEG micelles can effectively enhance the cellular uptake and cellular internalization of porphyrin and have an extremely low dark toxicity with efficient PDT towards A549 cells. This intracellular responsive nanoparticle provides a potential strategy for anticancer therapeutic application. [ABSTRACT FROM AUTHOR]

In this work, a dicyanoisophorone-based turn-on fluorescent probe, DCIP , for highly selective and sensitive detection of cysteine was designed based on nucleophilic substitution mechanism. Moreover, compared with typical cysteine probes, DCIP showed great selectivity and sensitivity for cysteine over other amino acids including the similar structured homocysteine (Hcy) and glutathione (GSH). Further, the detection limit toward cysteine was calculated to be as low as 0.70 μM. In addition, the utility of DCIP as a bioanalytical molecular tool was demonstrated by fluorescence imaging of biothiols in living cells. [ABSTRACT FROM AUTHOR]

Sulfur-based heterocycles were one of appealing building blocks in functional materials, due to their outstanding optical/electronical performance. Assembled DTTF-BTh which combined from two different sulfur heterocycles was synthesized by condensation of 2-cyanoethylthio-3-methylthio-6, 7-bis (hexylthio) tetrathiafulvalene ( TTF-1), and 4, 4′-bis (2′-bromoethoxy)- 3, 3′-bithiophene ( DBE-BTh). The full structural and physical characterizations of novel DTTF-BTh were studied by H NMR, Mass, UV-Vis absorption, and electrochemical measurements. The two heterocycle moieties were connected successfully but inclined to perform individually. This could be explained as electron separation by alkyl chains. Electropolymerization was also conducted. The result indicated that DTTF-BTh could directly form polymeric films on prepared ITO glass via electrochemical deposition. Moreover, the deposited polymer film possessed an electrochromic performance. [ABSTRACT FROM AUTHOR]

A novel fluorescent probe based 1,8-naphthalimide (NFH) for fluoride naked-eye recognition was synthesized, and it displayed high selectivity and sensitivity. The color and fluorescence changes of probe NFH can be observed only in presence of F − among various anions (F − , Cl − , Br − , I − , AcO − , NO 3 − , HSO 4 − , H 2 PO 4 − ). Furthermore, 1 H NMR titration indicated the deprotonation of acylhydrazone ( NH C O) which was induced by the interaction of F − ions and NH moieties. Theoretical calculation based on DFT explored the photoinduced electron transfer (PET) signaling mechanism of NFH toward F − which explained the striking fluorescent quenching of probe NFH after being treated with F − ions. [ABSTRACT FROM AUTHOR]

In this work, a dicyanoisophorone-based fluorophore, which showed an attractive near-infrared fluorescence as well as a favorable large stokes shift, was used to develop a novel probe ( NIR-Probe 1 ) for effective detection of biothiols. It displayed distinct color changes and a turn-on NIR fluorescence response with a high off/on ratio toward biothiols. We demonstrated that NIR-Probe 1 exhibited fast sensing speed, high selectivity for biothiols and possessed the function of detecting low concentration of biothiols with impressive limit of detection: 12.1 nM for Cys, 14.5 nM for Hcy and 11.9 nM for GSH. Moreover, the utility of NIR-Probe 1 as a bioanalytical molecular tool was demonstrated by fluorescence imaging of biothiols in living cells. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to explore the optic performance of extended stilbene derivative.Design/methodology/approach Five steps were adopted to synthesise novel 4, 4′-bis (2-cyanostyryl) stilbene, which contained three vinyl units in the skeleton (S3E). The structure of S3E was characterised by 1H NMR and EI-MS. Its absorption and emission spectra were also given.Findings Compared to C.I. Fluorescent Brightener 199, which contains two vinyl units in the skeleton, S3E showed obvious bathochromic shifts in both UV-VIS and FL spectra. The maximum absorption wavelength and fluorescent wavelength were at 390 nm and 464 nm, respectively, with Stoke’s shift of 74 nm. The absolute fluorescence quantum yield was 0.42. Thermogravimetric analysis (TGA) revealed that the weight loss of S3E was less than 5 per cent at 300 °C. Moreover, the light resistance test showed that S3E in PVC plate can keep the good fluorescent intensity for more than seven days exposed to xenon light. Therefore, it is believed that S3E could satisfy the requirements of colouring PVC as a fluorescent dye.Practical implications S3E can be used as a candidate of fluorescent dye in the development of thermoplastics.Originality/value The present paper designed and synthesised a new derivative of stilbene, which showed its preference to be a colourant of thermoplastics. [ABSTRACT FROM AUTHOR]

Based on benzothizazole and 1,8-naphalimide, a novel colorimetric and fluorescent probe (probe 1 ) for fluoride ion was synthesized by Schiff base reaction. The striking yellow-to-blue color change of the probe 1 in the CH 3 CN was observed with the naked eyes only in presence of F − among the eight anions (F − , Cl − , Br − , I − , NO 3 − , HSO 4 − , H 2 PO 4 − , AcO − ). Besides that, upon addition of F − , both of the absorption and emission peaks shifted to near-infrared region (NIR) (>600 nm) in UV–vis and fluorescent spectra, and the detection limit reached as low as 0.41 μM. Furthermore, the 1 H NMR titration and theoretical calculation based on TD-DFT indicated that the fluoride ion induced deprotonation of the probe 1 through hydrogen bonding interaction between amino group of probe 1 and fluoride ion. [ABSTRACT FROM AUTHOR]

A novel near infrared ratiometric fluorescent chemosensor based on triphenylamine, thiophene and benzothiadiazole has been developed. The emission wavelength of sensor DTPAT-BT-S was in the near infrared region. The wavelength changed from 656 nm to 723 nm, and got a rather long stokes shift about 170 nm. The sensor showed a very high selectivity towards Hg 2+ ions. [ABSTRACT FROM AUTHOR]

A new dyad composed of a naphthalimide unit and a spiropyran unit with a piperazine unit as the bridge has been synthesized to mimick the Three State Logic (TSL) gate and the luminescence was recorded as the output. Inputs including Protonation, deprotonation, UV irradiation and Fe 3+ coordination were employed to modulate the emission because of their distinctive outputs. Transient fluorescence and theoretical calculation were performed to further investigate the PET and FRET processes. [ABSTRACT FROM AUTHOR]

Rhodol is an ideal platform for fluorescent probes owing to its spirolactone framework and excellent photochemical properties. Herein, a novel rhodol-based colorimetric and fluorescent turn-on probe, DER-1 , for the detection of Pd 0 , was rationally developed with an allyl carbamate group as the response unit. Base on the Pd 0 -triggered cleavage reaction and rhodol spiroring-opening mechanism, the proposed probe exhibited a high selectivity and sensitivity towards Pd 0 . Upon addition of Pd(PPh 3 ) 4 , a significant fluorescence enhancement at 547 nm was observed with an obvious color change from colorless to pink, which can be easily identified by naked-eye. In addition, the fluorescence intensity at 547 nm was linearly proportional to the concentration of Pd 0 in the range of 0–1.5 μM, and the detection limit was calculated to be 1.14 nM. That is, probe DER-1 can be quite a sensitive fluorescent turn-on probe for the quantitative detection of Pd 0 in pretty low dose. [ABSTRACT FROM AUTHOR]

A novel coumarin-based compound 1 featuring thiosemicarbazone as binding unit, was reported as a colorimetric and fluorescent probe for the detection of fluoride anion. The addition of F − to a solution of probe 1 in tetrahydrofuran resulted in evident naked-eye color change from green-yellow to orange-red under daylight and obvious fluorescence quenching within 3 s. And the detection limit toward F − was calculated to be as low as 2.16 × 10 −7 mol/L. 1 H NMR titrations proved that the interaction between 1 and fluoride ion: hydrogen bond at low fluoride ion concentration, deprotonation at high fluoride ion concentration. Besides, it exhibited highly sensitivity and selectivity for F − over other examined ions (Cl − , Br − , I − , AcO − , NO 3 − , HSO 4 − , H 2 PO 4 − ) in tetrahydrofuran solution. [ABSTRACT FROM AUTHOR]

A new dual chemosensor ( TTF-PBA ) for Fe 3+ and Cu 2+ in different signal pathways was designed and synthesized. The absorption spectrum, fluorescence spectrum and cyclic voltammograms changed in the presence of Cu 2+ and Fe 3+ . The optical color changed within 5 s from yellow to orange upon the addition of Cu 2+ , and it changed to dark yellow when Fe 3+ existed. The cyclic voltammogram of Cu 2+ /TTF-PBA changed from E ox = 0.50 V, E red = 0.32 V to E ox = 0.64 V, E red = 0.80 V ( vs Ag/AgCl) upon the addition of 2.0 equiv. Cu 2+ . As for Fe 3+ /TTF-PBA, its oxidation wave disappeared, and its reduction wave appeared at E red = −0.59 V ( vs Ag/AgCl) upon the addition of 4.0 equv. Fe 3+ . The sensor displayed high selectivity for Cu 2+ and Fe 3+ over other ions including Pb 2+ , Zn 2+ , Ni 2+ , Ag + , Cr 3+ , Mn 2+ , Al 3+ , Co 2+ , Pd 2+ , Hg 2+ , Fe 2+, Cd 2+ , Ce 3+ , Bi 3+ and Au 3+ , the detection limits for Cu 2+ and Fe 3+ ion reached as low as 5.33 × 10 −7 mol/L and 5.34 × 10 −7 mol/L, respectively. Furthermore, when Fe 3+ existed, Cu 2+ can be detected sequentially by the sensor through the absorption spectrum and the color change observed by naked-eyes. [ABSTRACT FROM AUTHOR]

A new near-infrared colorimetric and ratiometric fluorescent chemodosimeter for Hg 2+ detection was devised, with a donor-acceptor-donor (D-A-D) molecular configuration and containing a dithioacetal group served as a sensing unit, and with a large stokes shift over 160 nm. The oxidation reaction of Hg 2+ broke the electron-donating interaction of dithioacetal moiety, and the obstruction in the intramolecular charge transfer (ICT) induced remarkable changes in the absorption and emission spectra. The sensor exhibited splendid selectivity and anti-interference performance towards Hg 2+ over other cations (K + , Na + , Ag + , Fe 2+ , Co 2+ , Mn 2+ , Zn 2+ , Ca 2+ , Pb 2+ , Ni 2+ , Mg 2+ , Cu 2+ , Al 3+ , Fe 3+ ). The mechanism was investigated by absorption and emission spectra together with 1 H NMR titration. [ABSTRACT FROM AUTHOR]

A novel and simple fluorescence probe was synthesized from benzo[1,2- b:4,5- b′]dithiophene (BDT) and trimethylsilylethyne via Sonogashira reaction, and showed highly selective and sensitive fluorescence decreasing response towards F−. The probe molecule turned to a weakly fluorescent terminal alkyne moiety because its trimethylsilyl (TMS) group was cleaved by fluoride, which was proved by 1H NMR titration. Whereas no distinct fluorescent changes were observed with the addition of other anions, such as Cl−, Br−, I−, AcO− and H2PO4−. Upon the addition of F−, the maximum fluorescence emission wavelength shifted from 460 nm to 450 nm with a decrease of fluorescence intensity by 40% within 20 s. Moreover, the detection limit towards F− was calculated to be as low as 73.5 nmol/L. [ABSTRACT FROM AUTHOR]

A new colorimetric fluorescent probe, 3-benzothiazolyl-coumarin-7-yl picolinate (P1) , based on coumarin derivative has been designed and synthesized to detect Cu 2+ in CH 3 CN-water (1:1,v/v) solution. The probe showed highly selective and sensitive fluorescence enhancement response towards Cu 2+ via selective hydrolysis reaction of the picolinate moiety followed by generating a strongly fluorescent 3-benzothiazolyl-7-hydroxycoumarin ( 2 ) moiety, whereas other competing metal cations (Na + , K + , Mg 2+ , Ag + , Fe 3+ , Pb 2+ , Mn 2+ , Ca 2+ , Ni 2+ , Cr 3+ , Zn 2+ , Sn 2+ , Hg 2+ , Al 3+ , Pd 2+ , Pt 2+ , Co 2+ , Au 3+ ) did not possess the property. Upon the addition of Cu 2+ , the color of P1 changed from colorless to yellow-green, and gave an emission at around 470 nm. Moreover, the detection limit toward Cu 2+ was calculated to be as low as 23.9 nM. [ABSTRACT FROM AUTHOR]

A novel turn-off probe for copper(II) containing benzo[1,2-b:4,5-b′]dithiophene (BDT) and two picolinamide units was synthesized. In this probe, two picolinamide units complex with one Cu 2+ ion and two nitrogen atoms in each picolinamide unit coordinate with Cu 2+ , which is verified by DFT calculation. Its fluorescence quantum yield is 0.43 and the detection limit is as low as 2.4×10 −8 mol/L. The results show that the probe displays good selectivity for Cu 2+ over other ions (Mn 2+ , Pb 2+ , Cr 3+ , Zn 2+ , Ni 2+ , K + , Ca 2+ , Ag + , Mg 2+ , Fe 3+ , Fe 2+ , Hg 2+ , Al 3+ , Cd 2+ , Pd 2+ , Co 2+ ). Furthermore, the probe induced by Cu 2+ and the π–π interaction of the aromatic unit can also form rod structure assembly, which can be observed by scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

A chemical sensor containing triphenylamine and benzothiadiazole for cyanide anions detection was designed and synthesized, whose structural feature is a donor-acceptor-donor (D-A-D) molecular configuration, which is substituted with a dicyanovinyl group served as a sensing unit. The nucleophilic addition of cyanide ion to the dicyanovinyl moiety was activated in the principle of Michael addition, which broken the electron-withdrawing interaction of dicyanovinyl moiety. The obstruction in the intramolecular charge transfer (ICT) induced remarkable changes in the absorption and emission spectra. The sensor exhibited splendid selectivity and anti -interference performance towards CN − over other anions (F − , Cl − , Br − , I − , NO 2 − , NO 3 − , HCO 3 − , H 2 PO 4 − , HS − , HSO 3 − , NCO − , SCN − , SO 3 2− , SO 4 2− , HPO 4 2− , CO 3 2− ). The mechanism was investigated by absorption and emission spectra together with 1 H NMR titration. [ABSTRACT FROM AUTHOR]

Monomer 5 was designed and synthesized via Steglich esterification reaction by connecting 3, 4-propylenedioxythiophene methanol (2) and derivative of tetrathiafulvalene (3). The structure was characterized by EI-MS, 1 H NMR and elemental analysis. Its behavior and performance were studied via comparison to monomer 4. The result indicated that the intramolecular charge transfer of 5 was greatly inhibited due to the broadened band gap as well as the twisted plane of the molecule. [ABSTRACT FROM AUTHOR]

Two novel 2,1,3-benzothiadiazole derivatives, used as colorimetric and fluorescent sensors for fluoride ion were designed, synthesized and characterized. These sensors contained single hydrogen-bond functional groups, which acted as interacting sites for fluoride ion. Both sensors displayed a red color in dimethyl sulfoxide solution. Binding studies revealed that they showed noticeable colorimetric and fluorescent responses only to F − among the eight anions tested (F − , Cl − , Br − , I − , AcO − , H 2 PO 4 − , HSO 4 − and NO 3 − ). 1 H NMR titration proved that the interaction between compounds and fluoride ion: hydrogen bond at low fluoride ion concentration, deprotonation at high fluoride ion concentration. Moreover, those compounds showed high sensitivity and selectivity for fluoride ion by inhibiting the excited state intramolecular proton transfer processes, and the detective processes could be followed by direct visual observation. [ABSTRACT FROM AUTHOR]

Two novel donor-π-acceptor chemosensors, exTTF-DPA and exTTF-ADPA, based on π-extended tetrathiafulvalene (exTTF) and di(pyridine-2-ylmethyl)amine (DPA) were synthesized and used as optical and electrochemical chemosensors for copper(II). The results showed that they possess specific selectivity for copper(II) in the presence of other competing metal ions (Zn 2+ , Sn 2+ , Pb 2+ , Pd 2+ , Hg 2+ , Al 3+ , Fe 3+ , Ag + , Co 2+ , Ni 2+ ) in acetonitrile. Upon the addition of Cu 2+ , the solution color changed from yellow to orange, the cyclic voltammograms changed dramatically and the fluorescence quenched completely. [ABSTRACT FROM AUTHOR]

In view of palladium contaminants and their adverse effects on human health, it is valuable to develop an effective probe for palladium. In this work, a coumarin-based colorimetric and turn-on fluorescent probe, Cou-1 , for highly selective and sensitive detection of palladium was designed based on the Tsuji–Trost allylic reaction. Upon the addition of palladium to the solution of probe, the probe gave an emission peak at around 498 nm as well as displayed a selective chromogenic behavior toward palladium from colorless to yellow-green, which could be easily observed by the naked eye. Moreover, compared with typical transition metal cations and other common cations used, Cou-1 showed great selectivity toward palladium. Further, the detection limit toward palladium was calculated to be as low as 17.4 nM. [ABSTRACT FROM AUTHOR]

Two copolymers (P1 and P2), bearing 3,4-ethylenedioxythiophene and fluorene moieties, were synthesized via Sonogashira coupling reaction successfully and P2 contains additional tetrathiafulvalene derivatives (TTFs) as pendants. The structures and properties of copolymer P1 and P2 were investigated by Infrared spectra, UV-visible spectra, and fluorescence spectra. Spectra analyses revealed that the fluorescent intensity of P2 was only 2 % compared to that of P1 in solution. The quenched fluorescent intensity of P2 could be recovered after adding defined moles of Fe(ClO) as an oxidant. The phenomenon was discussed with aid of computational stimulation in Gaussian 03. Herein, it is believed that intramolecular charge transfer occurs between TTF pendants and polymeric backbone in P2. P2 could be treated as a reporting group in fluorescent testing/switching system. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Reaction between 3,3′-dibromothiophene and sodium methylate/methanol in the presence of KI/CuO afforded 3-bromo-4-methoxythiophene as a major product. It was transformed into 4,4′-dimethoxy-3,3′-bithiophene by using Pd(OAc) as a catalyst and agarose as a ligand. The conditions of the reaction were mild with an acceptable yield of 20 %. The product was characterized by MS, H NMR, and its spectra of UV-Vis and cyclic voltammetry were given. Graphical Abstract: 4,4′-dimethoxy-3,3′-bithiophene was synthesized from 3-bromo-4-methyloxy thiophene in the homogeneous system formed by water and agarose.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A series of new A–π–D–π–A molecules including diphenylamine and carbazole had been synthesized and characterized ( T1 – T3 ). T1 and T2 displayed aggregation-induced emission enhancement (AIEE): exhibiting weak fluorescence in pure THF, which a signification AIEE effect was observed in mixture with a water fraction ( f w ) of 90% with a sharp increase in fluorescence intensity. T3 displayed aggregation-caused quenching (ACQ): exhibiting strong fluorescence in pure THF, which a signification ACQ effect was observed in mixture with a water fraction ( f w ) of 90% with a sharp decrease in fluorescence intensity. Their two-photon absorption (2PA) had been investigated using the open-aperture Z-scan technique, and the values of the 2PA cross section at 800 nm for T1 – T3 were 1115, 681, in chloroform, respectively. [ABSTRACT FROM AUTHOR]

Two copolymers, poly(1,1-dimethyl-3,4-diphenylsilole-alt- N-hexyl-3,6-diethynylcarbazole) (PS-DyCz) and poly(1,1-dimethyl-3,4-diphenylsilole-alt-2,7-diethynyl-9,9′-dihexylfluorene) (PS-DyF), were synthesized by Sonogashira coupling reaction of 2,5-dibromo-1,1-dimethyl-3,4-diphenylsilole and N-hexyl-3,6-diethynylcarbazole or 2,7-diethynyl-9,9′-dihexylfluorene, respectively. The chemical structures of the copolymers were characterized by NMR, FT-IR techniques. Their thermal and photophysical properties were evaluated by TGA, DSC, UV-Vis and fluorescence spectroscopy, respectively. The weight-averaged molecular weights ( Mw) of PS-DyCz and PS-DyF are 1.20×104 and 3.83×104 Da, respectively. The degree of polymerization is 8 and 22 units. These π-conjugated polymers exhibited lower band-gap of 2.25 and 2.70 eV due to the presence of silole rings and CC triple bonds in their backbone, the results were consistent with the density functional (DFT) calculations at the B3LYP/6-31G* level. [ABSTRACT FROM AUTHOR]

New donor–linker–acceptor pattern organic dye containing a dithienosilole unit as a π-conjugated system, a carbazole moiety as an electron donor, and a cyanoacrylic acid unit as an electron acceptor was synthesized for application in dye-sensitized solar cell ( DSSC ). Its photophysical and electrochemical properties were investigated, the dithienosilole unit could dramatically lower the lowest unoccupied molecular orbital ( LUMO ) level and energy gap. Its performances as sensitizers in solar cells were measured, and possessed a power conversion efficiency of 4.80%. [ABSTRACT FROM AUTHOR]

3,4-(Hydroxymethyl-ethylenedioxy)thiophene ( 4) and 3,4-(2′-hydroxypropylenedioxy)thiophene ( 4'′) were synthesized from dimethyl 3,4-dihydroxythiophene-2,5-dicarboxylate ( 1), which were isomers and difficult to separate. When they were esterified with tetrathiafulvalene carried carboxylic acid group, only 3,4-(hydroxymethyl-ethylenedioxy)thiophene ( 4) could be esterified. No such selectivity was observed when the isomers were esterified by lauric acid and benzoic acid, respectively. [ABSTRACT FROM AUTHOR]

Two conjugated ethynyl-linked oligomers, oligo(benzodithiophene-ethynylene-benzothiadiazole) (O1) and oligo(benzodithiophene-ethynylene-carbazole) (O2), were synthesized by Sonogashira coupling reaction. Their degrees of polymerization were 7 and 10, respectively. Their photophysical and electrochemical properties were investigated. O1 exhibitd two strong absorption bands at 404 nm and 483 nm, and O2 at 401 nm and 429 nm. The results of UV-Vis, cyclic voltammetry (CV) and theoretical calculations showed that O1 has a narrower band gap than O2. The conductivities of O1 and O2 were 1.05×10−15 and 6.98×10−16 S/cm, respectively, and would increase to 1.23×10−10 and 1.05×10−10 S/cm after doping with iodine. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two new d–π–A porphyrins TP and BUTP were synthesized for the first time. [•] Power conversion efficiency of DSSCs sensitized by TP reached 4.39%. [•] Power conversion efficiency of DSSCs sensitized by BUTP reached 5.33%. [Copyright &y& Elsevier]

A new conjugated copolymer (PTST-DyOXD) derived from 1,1-dimethyl-3,4-diphenyl-2,5-bis(5-bromo-2-thienyl)-silole (TST) and 2,5-bis(4-ethynylphenyl)-1,3,4-oxadiazole (DyOXD) was synthesized by Pd(0)-catalyzed Sonogashira coupling reaction. For comparison, another copolymer without acetenyl group (PTST-OXD) was also synthesized by Pd(0)-catalyzed Suzuki coupling reaction. Chemical structures and optoelectronic properties of the copolymers were characterized by 1H NMR, 13C NMR, IR, UV-vis absorption, photoluminescence and cyclic voltammetry. The number-average molecular weight ( Mn) is 4010 Da for PTST-DyOXD and 3890 Da for PTST-OXD, respectively. The thermogravimetric analysis (TGA) measurements show that they have good thermal stability with decomposition temperature at 312 and 318°C, respectively. The optical band gap is 2.21 eV for PTST-DyOXD and 2.10 eV for PTST-OXD based on the absorption onset. CV analysis revealed the LUMO level of PTST-DyOXD is −3.04 eV, lower than that of PTST-OXD (about −2.89 eV), which is attributed to the introduction of acetylene group in PTST-DyOXD, increasing the system of the conjugate chain length. [ABSTRACT FROM AUTHOR]

A kind of π-conjugated poly(EDOT-ethynylene-arylene)s P1- P5 were synthesized by Sonogashira coupling reaction between DBEDOT and five arylenes substituted with ethynyl groups. Among them, P5 was a polymer with TTF as pendants. Their TGA results exhibited their good thermal stability and their electrochemical and spectroscopic properties were investigated by CV, UV-Vis, and FL. The results indicated that there were intramolecular interactions between TTF group and polymer backbone as well as between the EDOT and arylene moieties. After doping with TCNQ, P5 could form stable CT-complex with a conductivity of 1.3 × 10 S cm, while its conductivity could be up to 3.5 × 10S cm after doping with I, due to its increased conductive dimensions. Such results indicated that this polymer had potential application in developing conducting materials. Graphical Abstract: A kind of π-conjugated EDOT-ethynylene-fluorene polymer with TTF as pendants was synthesized, which exhibited good solubility and thermal stability. When doping with I, its conductivity was improved significantly due to its increased conductive dimensions.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Three routes were designed to synthesize a π-conjugated aryleneethynylenesiloles dendron. With the desilylation of the disilole mono(silylethynyl) derivative in the presence of potassium carbonate (K2CO3), the silole-containing oligomer has been successfully synthesized without impact on the Si-(CH3)2 group. The disilole mono(silylethynyl) derivative was prepared by means of the Sonogashira heterocoupling reaction between the diacetylene compound and asymmetrical silole, catalyzed by the dichloro bis(triphenylphosphine)palladium, in a divergent synthesis. Due to their steric effect and triethynylbenzene self-coupling Glaser reaction, the endeavour to prepare the dendron by controlling the molar ratio of asymmetrical silole and 1,3,5-triethynylbenzene was failed. The another attempt to prepare the dendron by different desilylation condition of triisopropylsilyl group and trimethylsilyl group was also failed, the desilylation of Si-(CH3)2 group in silacyclopentadiene unit was also easily accomplished in the presence of tetrabutylammonium fluoride(Bu4NF), whereas no reaction occurred when K2CO3 was used instead of Bu4NF. [ABSTRACT FROM AUTHOR]

Silole-core phenylacetylene dendrimers were designed and synthesized, among them, the model compound ( n = 0) and the first generation of the dendrimer ( n = 1) were obtained by the reaction of 2,5-dibromosilole with corresponding terminal alkynes, the second generation of the dendrimers ( n = 2) was synthesized from 2,5-diiodosilole. These compounds indicated the absorptions of both phenylacetylene dendrons (250-350 nm) and silole core (400-500 nm). The first generation displayed efficient energy transfer from phenylacetylene dendrons to silole core, whose energy transfer efficiency was as high as 80%. These compounds were used as chemical sensors to probe explosive, for picric acid (PA), the Stern-Volmer constants of model compound and the first generation are 7120 and 5490 M−1, respectively. J. Heterocyclic Chem., (2012). [ABSTRACT FROM AUTHOR]

A series of conjugated ethynylene-fluorene polymers with electro-donating TTFas pendant groups (P2–P4) were synthesized by using Sonogashira coupling reaction, and two functionalization methods, i.e.prepolymerization and postpolymerization, were developed. The composition and purity of the corresponding products were analyzed by 1H NMR. The results proved the functionalization of P2(pre) and P2(post) were 40% and 100%, respectively. The results also indicated that the postpolymerization method would be a better approach to prepare TTF-pendant conjugated ethynylene-fluorene polymers. The postpolymerization methodology could be extended to synthesize other conjugated fluorene-based polymers bearing TTFunits (P3and P4). The polymers mentioned above exhibited good solubility in normal organic solvents and higher conductivity (neutral conductivity ∼2–4 × 10−6S cm−1; doped conductivity ∼1–3 × 10−3S cm−1). Moreover, the fluorescence intensity of P2(post) could be modulated by the oxidation of TTFunits, which makes it an attractive candidate for the fluorescence switch. [ABSTRACT FROM AUTHOR]

A novel copolymer, D-α-tocopheryl polyethylene glycol 1000 succinate-block-Poly (ε-caprolactone) (TPGS-block-PCL), was synthesized and characterized by 1H-NMR and FTIR. The molecular weight was determined by gel permeation chromatography. TPGS-block-PCL can be used to prepare microparticles for drug delivery system by a modified solvent extraction/evaporation method without extra emulsifier. The risperidone-loaded microparticles were characterized by laser light scattering for particle size and by scanning electron microscopy (SEM) for surface morphology. The drug encapsulation efficiency and the in vitro drug release profiles were measured. A significantly higher drug release rate was observed for microparticles with TPGS-block-PCL copolymer than PCL. [ABSTRACT FROM AUTHOR]

The characteristics of self-nanoemulsifying drug delivery system (SNEDDS) of Anethole trithione (ATT) for oral administration by the combined use of surfactants were investigated. In combination with surfactants, the SNEDDS provided smaller particle size, more oil loading, and shorter emulsification time. ATT from the SNEDDS rapidly dissolved in dissolution media whereas the ATT tablets showed different dissolution patterns according to the dissolution media. Furthermore, loading of ATT in SNEDDS improved the stability of ATT, and particle size of ATT nanoemulsion generated upon dilution was kept constant both in simulated gastric fluid and simulated intestinal fluid without enzyme. [ABSTRACT FROM AUTHOR]

Abstract: Two donor-σ-acceptor-σ-donor triads incorporating tetrathiafulvalene (TTF) and 3,4,9,10-perylene tetracarboxylic diimides (PDI) units were synthesized. The structures of the triads and their intermediates were characterized by 1H NMR, 13C NMR, MS, IR. The results of UV–vis and cyclic voltammetry (CV) of the triads indicated negligible intramolecular charge transfer (ICT) interaction in their ground states. The fluorescence and fluorescence lifetimes of the triads were reduced compared to PDIs, which evidently indicated that photoinduced electron transfer (PET) interaction occurred from the TTF unit to the PDI unit in the excited state. The fluorescence intensity of the triads could be reversibly modulated by sequential oxidation and reduction of the TTF unit using the chemical methods. Therefore two new fluorescence molecular switches based on TTF and PDI units were established. [Copyright &y& Elsevier]

Abstract: Difluoroiodomethylsulfanylbenzene (3a) and 1-chloro-4-difluoroiodomethylsulfanylbenzene (3b) are novel and efficient difluoromethylating reagents via the reaction with unsaturated compounds, such as alkenes, ethynylbenzene, pent-4-en-1-ols, and pent-4-enoic acids initiated by Na2S2O4, to afford the corresponding adducts, tetrahydrofuran derivatives, and γ-butyrolactones containing difluoromethylene group in moderate to good yields. [Copyright &y& Elsevier]

Abstract: High-speed counter-current chromatography (HSCCC) was applied to preparative separation and purification of dl-tetrahydropalmatine from Corydalis yanhusuo by a one-step separation. The two-phase system consisted of petroleum ether–ethyl acetate–methanol–water (15:30:21:20, v/v) was employed. An orthogonal design was used for optimizing the revolution speed of the separation column, flow rate of the mobile phase and separation temperature, which was 850rpm, 1.2ml/min and 20°C, respectively. HPLC analysis of the fractions collected by preparative HSCCC of 200mg of crude extracts showed that the purity of dl-tetrahydropalmatine (8.6mg) was 96.4%. The chemical identity of the component was confirmed by 1H NMR and EI-MS. [Copyright &y& Elsevier]