聚苯胺／含联苯结构聚芳砜导电复合膜的研究

采用溶液共混法得到了聚苯胺／含联苯结构聚芳砜导电复合膜。该复合膜有良好的力学性能和导电性能，对其导电规律进行了探讨。热分析结果表明复合膜有良好的热稳定性，用扫描电镜观察了复合膜的微观形貌，表明ＰＡｎ与ＬＰＥＳ的共混相容性较好。     

Automated in-tube solid-phase microextraction-high-performance liquid chromatography for carbamate pesticide analysis

In-tube solid-phase microextraction (SPME) is an automated version of SPME that can be easily coupled to a conventional HPLC autosampler for on-line sample preparation, separation and quantitation. It has been termed "in-tube" SPME because the extraction phase is coated inside a section of fused-silica tubing rather than coated on the surface of a fused-silica rod as in the conventional syringe-like SPME device. The new in-tube SPME technique has been demonstrated as a very efficient extraction method for the analysis of polar and thermally labile analytes. The in-tube SPME-HPLC method used with the FAMOS autosampler from LC Packings was developed for detecting polar carbamate pesticides in clean water samples. The main parameters relating to the extraction and desorption processes of in-tube SPME (selection of coatings, aspirate/dispense steps, selection of the desorption solvents, and the efficiency of desorption solvent, etc.) were investigated. The method was evaluated according to the reproducibility, linear range and limit of detection. This method is simple, effective, reproducible and sensitive. The relative standard deviation for all the carbamates investigated was between 1.7 and 5.3%. The method showed good linearity between 5 and 10000 microg/l with correlation coefficients between 0.9824 and 0.9995. For the carbamates studied, the limits of detection observed are lower than or similar to that of US Environmental Protection Agency or National Pesticide Survey methods. Detection of carbaryl present in clean water samples at 1 microg/l is possible.     

mu4-Dicarbyne complex with a dimetallacyclobutatriene core: a new binding mode of C2 species

Reaction of a permetallated ethene, (mu4-C=C)Fe2R-mu2Cp*2(CO)10, with diphenylacetylene affords the adduct with a new C2-binding mode, a mu4-dicarbyne complex, (mu4-C-C)Fe2Ru2Cp*2(CO)6(mu-Ph-C[triple bond]C-Ph), containing a dimetallacyclobutariene core.     

Cleavage of C-S bonds with the formation of a tetranuclear Cu(I) cluster

The treatment of a ligand, 2,6-bis((4-(pyridin-2-yl)pyrimidin-2-ylthio)methyl)-4-chlorophenol (ClPPT2), with cuprous chloride under a weak base condition led to the formation of a neutral CuI4-centered cluster [Cu4(PPT2)4], whose X-ray diffraction analysis indicated that C-S bonds of the ligand were cleaved in the course of the reaction. To explain the C-S bond cleavage, a reasonable mechanism has been proposed. In support of it, four additional ligands, 2,6-bis((4-(pyridin-2-yl)pyrimidin-2-ylthio)methyl)-4-methylphenol (MePPT2), 2,6-bis((4-(pyridin-3-yl)pyrimidin-2-ylthio)methyl)-4-methylphenol (MePPT3), 2,6-bis((4-(pyridin-3-yl)pyrimidin-2-ylthio)methyl)-4-chlorophenol (ClPPT3), and 5-((4-(pyridin-3-yl)pyrimidin-2-ylthio)methyl)-2-hydroxybenzaldehyde (HBPPT2) were further tested to undertake the analogous reaction, and the cleaved products in these experiments were detected by electrospray ionization mass spectrometry techniques to clarify the process.     

Highly regio- and stereoselective synthesis of indene derivatives via electrophilic cyclization

[reaction: see text] Indene or naphthalene derivatives are readily prepared in moderate to excellent yields with high regio- and stereoselectivity under very mild reaction conditions by the reaction of acetylenic malonates and ketones with I2, ICl, or NIS. The resulting iodides can be further elaborated using palladium-catalyzed coupling reactions.     

Syntheses, crystal structures, and spectral properties of a series of 3,8-Bisphenyl-1,10-phenanthroline derivatives: precursors of 3,8-Bis(4-mercaptophenyl)-1,10-phenanthroline and Its ruthenium(II) complex for preparing nanocomposite junctions with gold nanoparticles between 1 microm gap gold electrodes

A multistep synthesis was achieved to obtain 3,8-bis(4-mercaptophenyl)-1,10-phenanthroline, which has two free thiol end groups with a molecular length of 1.89 nm, and its ruthenium(II) complex. Five single-crystal structures and UV-vis spectra of related intermediates in methanol and the solid state were studied in order to obtain additional information on the molecules as well as on the supramolecular interactions in the structures. Thermal and electrochemical properties of related Ru(II) complexes were also involved. 3,8-Bis(4-mercaptophenyl)-1,10-phenanthroline and one of its ruthenium(II) complexes were then treated with gold nanoparticles (Au-NPs) via in situ thiol-to-thiol ligand exchange in the presence of two facing Au electrodes with a 1 x 1 microm(2) gap. Stable molecular junctions composed of self-assembled films were produced as revealed by an obvious increase of the conductivity between the Au electrodes, wherein dithiols-bridged Au-NPs were attached to the electrodes by means of Au-S-bonded contacts. Temperature-dependent current-voltage (I-V) measurements for the junctions were performed in the temperature range of 7-300 K, and classical Arrhenius plots and their linear fits were obtained to determine the average activation energies (DeltaE) of these devices. It is found that when the Ru(II) ion is introduced, the conductivity of the nanodevice is increased and the energy barrier is lowered under the same experimental conditions.     

LC-APCI-MS-MS method for the tissue distribution of viaminate after oral administrations to rats

Fast and sensitive liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) method for the specific determination of viaminate in 14 kinds of rat tissues pre-treated with simple procedure was developed and validated. Biological samples were prepared by direct precipitation to skin, stomach, intestine, and liver and extracted by liquid-liquid extraction to lung, kidney, muscle, spleen, brain, fat, testes (male and female), eye, and heart. After addition of menaquinon as internal standard to tissue homogenate, the supernatant was injected into the isocratic chromatographic system using a Waters Symmetry C8 column and methanol-water-formic acid (93:7:0.1) as the eluent. The eluate was completely led into an APCI interface with selected ion monitoring mode and the analytes were quantified using triple quadrupole MS. The assays were successfully validated in the ranges 0.02-20 ng/mL for lung, 0.02-10 ng/mL for kidney, spleen, muscle, brain, fat, eye, and heart, 0.05-10 ng/mL for testicle, 0.4-100 ng/mL for liver, skin and intestine, and 1.0-200 ng/mL for stomach. The accurate and precise studies showed good reproducibility with coefficients of variation below 8.5% and the recoveries range from 90 to 109%. The analytes were chemically stable under all relevant conditions and the assays were applied in tissue distribution study. The results showed that the viaminate concentration was high in skin, low in kidney, and almost undetectable in eye and brain.     

Highly regio- and stereoselective synthesis of indene and benzo[b]furan derivatives via a Pd-catalyzed carboannulation of propargyl carbonates with nucleophiles

A new and efficient synthesis of indene and benzo[b]furan derivatives has been achieved via Pd-catalyzed carboannulation of propargyl carbonates with nucleophiles in good to excellent yields with high regio- and stereoselectivity. A novel sequence of nucleophilic attack is observed, and a possible mechanism is proposed.     

New insight into Ni(II)-catalyzed cyclization reactions of propargylic compounds with soft nucleophiles: novel indenes formation

We have disclosed a very nice advance of nickel(II)-catalyzed carboannulation reactions. Highly substituted indene derivatives are readily prepared in moderate to excellent yields under very mild reaction conditions in air via a nickel(II)-catalyzed cyclization of propargylic compounds with soft nucleophiles.