Molecular simulation study of the microstructures and properties of pyridinium ionic liquid[HPy][BF_(4)]mixed with acetonitrile

The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.

Identification,structure elucidation and origin of a common pyridinium-thiocyanate intermediate in electrospray mass spectrometry among the benziamidazole-class proton pump inhibitors

During the analysis of benziamidazole-class irreversible proton pump inhibitors,an unusual mass spectral response with the mass-to-charge ratio at[Mt10]t intrigued us,as it couldn't be assigned to any literature known relevant structure,intermediate or adduct ion.Moreover,this mysterious mass pattern of[Mt10]t has been gradually observed by series of marketed proton pump inhibitors,viz.omeprazole,pantoprazole,lansoprazole and rabeprazole.All the previous attempts to isolate the corresponding component were unsuccessful.The investigation of present work addresses this kind of signal to a pyridinium thiocyanate mass spectral intermediate(10),which is the common fragment ion of series of labile aggregates.The origin of such aggregates can be traced to the reactive intermediates formed by acid-promoted degradation.These reactive intermediates tend to react with each other and give raise series of complicated aggregates systematically in a water/acetonitrile solution by electrospray ionization.The structure of the corresponding pyridinium thiocyanate species of omeprazole(10a)has been eventually characterized with the help of synthetic specimen(10a′).Our structural proposal as well as its origin was supported by in situ nuclear magnetic resonance,chemical derivatization and colorimetric experiments.

Preparation and Reactions of Pyridinium Ylids via Decarboxylation of Pyridinium Betaines

Pyridinium ylids 4 were generated as reaction intermediates from the decarboxylation of pyridinium betaines 3, which were prepared from the reactions of a-amino acid ester hydrochlorides with 2, 4, 6-triphenylpyrylium tetrafluoroborate. Protonation, addition and substitution reactions of 4 with electrophiles were studied in this paper.

The Reactivity of 2,4,6-Tirphenylpyridinium Ylids

Triphenylpyridinium ylid 2, generated by the decarboxylation of betaine 1, were noted to react with acetyl chloride, chloroform or acetone to form addition-elimination product and proton extraction - carbanion addition products, respectively. The reaction with chloroform was determined as pseudo first order from kinetic experiments. The values of kobsd and t1/2 for decarboxylation at 20, 40 and 50C were calculated to be 4.6 x 10-4, 8.8 x 10-3, 2.8 x 10-2 min-1 and 1.5 x 103, 78, 24 minutes, respectively.

n-Butyl Pyridinium Nitrate as a Reusable Ionic Liquid Medium for Knoevenagel Condensation

The Knoevenagel condensation of carbonyl substrates with active methylene compounds proceeds smoothly with ammonium acetate as catalyst in n-butyl pyridinium nitrate to afford the desired products of good purity in moderate yields.

A mild,simple and efficient method for selectiveα-monobromination of 1,3-diketones and β-ketoesters using pyridinium bromochromate

Pyridinium bromochromate has been found to be a highly efficient and selective reagent for the α-monobromination of 1,3- diketones and β-keto-esters in the absence of base, Lewis acid, or other catalyst. The products were formed in high to excellent yields under mild reaction conditions and in short reaction times.

A Facile Synthesis of Indolizines by 1，3－Dipolar Cycloaddition of Pyridinium and Related Heteroaromatic Ylides with Alkenes in the Presence of TPCD，Py_4Co（HCrO_4）_2

facile one-step method is presented for the synthesis of indolizines in moder-ate to high yields by reaction of pyridinium, quinolinium and isoquinolinium ylideswith acrylonitrile, methyl acrylate and diethyl maleate respectively in the presenceof tetrakis-pyridino-cobalt(Ⅱ)dichromate (TPCD) in DMF.

Homogeneous and Heterogeneous Performances of Pyridinium Ionic Liquids in the Allylic Oxidation of Ionone-like Dienes

The combination of relatively low-cost ionic liquids, simple copper salt, and terminal oxidant tert-butyl hydroperoxide provided an efficient and environmentally friendly approach to the preparation of ionone-like dienones. Six pyridinium ionic liquids were evaluated in allylic oxidation of α-ionone and β-ionone. The 60%-70% yields of 3-oxo-α-ionone were obtained with 0.02 0.20 mmol of CuCl2·2H2O as catalyst, 3-5 mmol of tert-butyl hydroperoxide as oxidant and 1 g of [Bpy]PF6 as solvent for 4-20 h at 60℃. The facile recovery and recycle of catalyst were also achieved. More significantly, peculiar phase behaviors of [Bpy]PF6 and [Epy]PF6 offered the catalytic system advantages of homogeneous reaction and heterogeneous separation. Scanning electron microscope （SEM） images of [Bpy]PF6 provided evidences for the behaviors. Transmission electron microscope （TEM） micrographs showed copper salt nanoparticles catalyst formed and stabilized in pyridinium ionic liquids.

Surface passivation using pyridinium iodide for highly efficient planar perovskite solar cells

Perovskite solar cells have developed rapidly in the past decades.However,there are large amounts of ionic defects at the surface and grain boundaries of perovskte films which are detrimental to both the efficiency and stability of perovskite solar cells.Here,an organic halide salt pyridinium iodide(PyI) is used in cation-anion-mixed perovskite for surface defect passivation.Different from the treatment with Lewis base pyridine(Py) which can only bind to the under-coordinated Pb ions,zwitterion molecule PyI can not only fill negative charged iodine vacancies,but also interact with positive charged defects.Compared with Py treatment,PyI treatment results in smoother surface,less defect densities and nonradiative recombination in perovskite,leading to an improved VOC, negligible J-V hysteresis and stable performance of devices.As a result,the champion PyI-treated planar perovskite solar cell with a high VOC of 1.187 V achieves an efficiency of 21.42%,which is higher than 20.37% of Py-treated device,while the pristine device without any treatment gets an efficiency of 18.83% at the same experiment conditions.

配合物[1-(4'-fluorobenzyl)pyridinium]_(2)[Ni(dto)_(2)](dto^(2-)=dithiooxalate dianion)的合成及晶体结构

The complex-(4’-fluorobenzyl)pyridiniu 2Ni (dto) 2(dto 2- means dithiooxalate dianion)has been pre-pared by reaction of Na 2Ni (S 2 C 2 O 2 ) 2and the 1-(4’-fluorobenzyl)pyridinium chloride salt.The crystallographic data for the title complex:triclini cP1,a=8.5698(8)?,b=9.3461(9)?,c=10.5361(10)?,α=67.177(2)°,β=67.398(2)°,γ=79.611(2)°,V=717.59(12)? 3 ,Z =1.TheNi (dto) 2 2- anion with the Ni atom lying on an inversion center and exhi bits a quasi-planar structure.An extensive hydrogen bond network of C -H...O is clearly observed.The nature and size of cation seems to play an important factor in the type of intermolecu lar interactions as well as the crystal packing in this kind of complexes.

Stereoselective Synthesis of Polysubstituted Cyclopropanes from Poly(ethylene glycol) Supported Pyridinium Ylide

Polysubstituted cyclopropanes were efficiently prepared with poly（ethylene glycol）（PEG） as soluble support. The reaction of PEG-supported pyridinium ylide with arylidenemalononitrile（R=CN） or ethyl arylidenecyanoa-cetate（R=COOEt） in the presence of triethylamine（TEA） afforded PEG-supported cyclopropanecarboxylates, which were cleaved by 1% KCN/EtOH to obtain polysubstituted cyclopropanes with exclusive trans-selectivity and good yields.

Preparation of Indolizine by Intramolecular 1,5-Dipolar Cycloaddition of Pyridinium N-Allylides

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Luminescent Properties of Tetrakis (1-(2-Thenoy)-3,3,3-Trifluoracetate) Europium N-Hexadecyl Pyridinium in Modified Si-MCM-41

Eu(TTA)4C5H5NC16H33(TTA:1-(2-Thenoy)-3,3,3-Trifluoracetate) is encapsulated in St- MCM-41 modified with N-(3-Trimethoxysilethyl)ethylene. The emission spectrum of the assembly shows only a 5D0-7F2 transition. As compared with the rare earth complex itself, the lifetime of the assembly becomes longer and its stability under the UV radiation is much better.

IONIC CONDUCTION IN BLENDS OF POLY(PYRIDINIUM ETHYL METHACRYLATE)AND COMB—LIKE COPOLYETHER

Poly(pyridinium ethyl methacrylate)was synthesized.The blends of polymeric solid anion conductor,P(PyEMAClO+4)/P(MEO_(16)—AM),were prepared. The temperature—dependence of both the conductivity and anionic mobility in the blends obey Arrhenius relationship,the transport of perchlorate anion being of thermal activation mechanism.Perchlorate anion is a free anion in the blends.

STUDIES ON DERIVATIVE FLUORIMETRY Ⅳ. DETERMINATION OF TRACE AMOUNT OF TERBIUM THROUGH ITS TERNARY COMPLEX WITH ACETYLACETONE AND EDTA IN THE PRESENCE OF CETYL PYRIDINIUM CHLORIDE

Terbium can form a ternary complex having a ratio of 1:1:1 with acetylacetone and EDTA. By adding cetyl pyridinium chloride into the above system, a marked enhancement of fluorescence intensity is observed and the ternary complex becomes more stable than before. For analytical application, the derivative spectrofluorimetric method has high sensitivity and the effect of foreign ions is very low. The optimum conditions were obtained. The calibration graph is linear over 5～100μg/mL.

STUDIES ON LANGMUIR-BLODGETT FILM OF METAL COMPLEXES(Ⅰ)-PREPARATION AND CHARACTERIZATION OF THE LB FILM OF N-HEXADECYL PYRIDINIUM TETRAKIS(1-PHENYL-3-METHYL-4-BENZOYL-PYRAZOL-5-ONE)EUROPIUM,C_5H_5NC_(16)H_(33)Eu(PMBP)_4

The LB film of the title complex was prepared by dropping a benzene solution of the title complex on the surfaceof water subphase at 25±1℃.The film was deposited in Z type on various hydrophilic pretreated substrates ofquartz,CaF;and electronic conductive glass for different purposes.The π-A curve of the film shows that thecross section per molecule is 125;,which indicates that the alkyl chain of the molecule is basically perpendiculalto the surface of the substrate.UV,IR spectra and transmission electronic microscopy of the film were also obtained.

BICENTRAL POLYMER SUPPORTED PHASE TRANSFER CATALYST POLYSTYRENE－SUPPORTED POLYETHYLENE GLYCOL AND PYRIDINIUM SALT

A bicentral polymer-supported Phase transfer catalyst, polystpyne-suPPorted polyethylene glycol and Pyridinium salt (PS-Py-PEG-400),synthesized with ohloromethylated polystyrene as supporter on which PEG and Pyridinium salt were immobilized successively. Its catalytic activity was tested for the reauction of solid potassium acetate and benzyl bromide by GC analysis. It was found that the bicentral catalyst performed higher activity than the monocentral PS-PEG-400 and PS-Py.

Efficient capture of difluorocarbene by pyridinium 1,4-zwitterionic thiolates:A concise synthesis of difluoromethylene-containing 1,4-thiazine derivatives

A practical method for the construction of difluoromethylene-containing 1,4-thiazine moieties using readily available diethyl bromodifluoromethanephosphonate(BrCF_(2)PO(OEt)_(2))as difluorocarbene precusor has been developed.This transformation features the efficient capture of difluorocarbene by pyridinium 1,4-zwitterionic thiolates.A series of structurally novel and functionalized difluoromethylene-containing 1,4-thiazine derivatives were thus synthesized in good yields.

Tuning the structures of polypyridinium salts as bifunctional cathode interfacial layers for all-solution-processed red quantum-dot light-emitting diodes

Self-doping cathode interfacial layers(CILs) with both favorable electron injection and transport characteristics meet the key requirement for realizing high-performance optoelectronic devices with simplified structures. Herein, four different polypyridinium salts with tunable backbones, side chains and counterions are elaborately designed to afford them desirable film-forming property, polarity, structural rigidity and self-doping feature. All-solution-processed red quantum dot light-emitting diodes(QLEDs) employing them as bifunctional CILs render remarkably improved device performances in contrast to the typical CIL material of poly[(9,9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)](PFN).The maximum external quantum efficiency of 2.74% achieved in this work represents one of the best values among the all-solution-processed QLEDs with individual organic CILs.