A novel MCM-41-supported sulfur palladium(0) complex catalyst for Sonogashira coupling reaction

A novel MCM-41-supported sulfur palladium(0) complex was conveniently prepared from commercially available and cheap γ-mercaptopropyltriethoxysilane via immobilization on MCM-41, followed by reacting with palladium chloride and then the reduction with hydrazine hydrate. This complex exhibited excellent performance in Sonogashira coupling reaction.     

Vapor pressure measurements on non-aqueous electrolyte solutions. Part 3: Solutions of sodium lodide in ethanol, 2-propanol,and acetonitrile

Precise vapor pressure data for solutions of Nal in ethanol from 0.04 to 1.9m, and 2-propanol and acetonitrile from approximately 0.06 to 1.5m are communicated and discussed. Polynomials in molalities are given for calculating precise reference values. Osmotic coefficients were calculated by taking into account the second virial coefficients of solvent vapors. Discussion of the data at low concentrations is based on the chemical model of electrolyte solutions and ion-pair association constants are compared to those obtained from other properties of sodium iodide solutions. Pitzer equations are used to reproduce osmotic and activity coefficients at high concentrations; the set of Pitzer parameters for methanol solutions b=3.2, ₁ = 2.0, and ₂ = 20.0 may be used for ethanol, 2-propanol, and acetonitrile solutions.     

Silicaphosphine (Silphos): a filterable reagent for the conversion of alcohols and thiols to alkyl bromides and iodides

Silicaphosphine (Silphos), [P(Cl)_3−n(SiO₂)_n], as a new heterogeneous reagent is introduced. This reagent converts alcohols and thiols to their corresponding bromides and iodides in the presence of X₂ (X=Br, I) in refluxing CH₃CN in high to quantitative yields. Use of Silphos provides a highly practical method for the easy separation of the Silphos oxide byproduct by a simple filtration.     

Synthesis,antifungal activity and in vitro mechanism of novel 1-substituted-5-trifluoromethyl-1H-pyrazole-4-carboxamide derivatives

Inspired by the wide application of amides in plant pathogens, a series of novel 1-substituted-5-trifluoromethyl?1H?pyrazole-4-carboxamide derivatives were designed and synthesized. Bioassay results indicated that some target compounds exhibited excellent and broad-spectrum in vitro and certain in vivo antifungal activities. Among them, the in vitro EC₅₀ values of Y₁₃ against G. zeae, B. dothidea, F. prolifeatum and F. oxysporum were 13.1, 14.4, 13.3 and 21.4 mg/L, respectively. The in vivo protective activity of Y₁₃ against G. zeae at 100 mg/L was 50.65%. SAR analysis revealed that the phenyl on the 1-position of the pyrazole ring was important for this activity. An antifungal mechanism study of Y₁₃ against G. zeae demonstrated that this compound may disrupt the cell membrane of mycelium, thus inhibiting the growth of fungi. These mechanistic study results were inconsistent with those for traditional amides and may provide a novel view for deep study of this series of pyrazole carboxamide derivatives.     

Some sources of defects in α-HgI2, the room temperature γ-ray detector

In the course of a systematic optimization of the materials properties of -HgI₂ crystals for room temperature - and X-ray detectors, we have investigated possible sources of defects and discuss briefly the possibility to supress them. Due to the particular structure of -HgI₂, large amount of impurities, particularly hydrocarbons, can be absorbed invan der Waals layers and lattice channels. Purification by sublimation does not work due to the affinity of hydrocarbons to iodine and their easy re-absorption in the sublimate. Lattice filtering of the large concentration of hydrocarbons contained even in suprapure iodine has been performed using the close spaced lattice of CuI. Oxidation of hydrocarbons by reaction of oxygen with HgI₂ is another possibility for their removal.Mass spectrometric investigations of a molecular beam of -HgI₂ has solved the long disputed problem of the existence of nonstoichiometry: both excess of Hg or excess of I are possible. The removal of nonstoichiometry can be achieved by suitable thermal treatment only in the case of pure crystals. In the presence of hydrocarbons, the non-stoichiometric defects are fixed showing the predominant importance of hydrocarbons for -HgI₂.Investigation of the evaporation of -HgI₂ with mass spectrometry at low temperatures (150>T>40 °C) shows a strong change of the enthalpy of evalporation at 67 °C whereas DSC does not show any peak at this temperature. It seems probable that this is due to a surface reconstruction which influences the evaporation but not the thermal bulk lattice effects which are detected by DSC.Dedicated to Prof. Dr.K. L. Komarek at the occasion his 60th birthday.     

三乙胺催化丙炔醇的聚合

本文应用三乙胺催化聚合丙炔醇。研究了该聚合反应的特征及动力学行为。制得带有光泽的褐色粘性固体产物,聚丙炔醇显示半导体及顺磁特性。     

A new, environment friendly protocol for iodination of electron-rich aromatic compounds

A new environment friendly procedure for effective aromatic iodination is presented. A mixture of potassium iodide and potassium iodate is used in the presence of an acid for in situ iodination of aromatic compounds.     

A simple, efficient, and highly selective method for the iodination of alcohols using ZrCl4/NaI

Iodination of primary, secondary, allylic, and benzylic alcohols giving their corresponding iodides was achieved with ZrCl₄/NaI in anhydrous CH₃CN with excellent yields and selectivities.     

Novel Organically Templated 2-D Silver(I)-Iodide Coordination Architecture: Syntheses and Characterization

A new two-dimensional silver(I)-iodide coordination architecture [(dbp · H₂)_1.5(Ag₆I₉)] _n (1) (dbp = N,N′-dibutyl-piperazine) templated by appropriate cation has been constructed and structurally, thermally and optically characterized. The compound crystallizes in monoclinic, space group P2(1)/n, a = 12.198(2) ?, b = 14.464(3) ?, c = 28.108(6) ?, β = 91.69(3)°, V = 4957.0(17) ?³, Z = 4, R ₁ = 0.0576 and wR ₂ = 0.1794[I > 2σ(I)]. The inorganic moiety of 1 presents two-dimensional arrangement that results from the apexes and edges-sharing of AgI₄ tetrahedrons. Electrostatic interactions between organic countercations and inorganic layers are presented and contribute to the crystal packing. Optical limiting measurement indicates that 1 possesses optical limiting activity.     

Synthesis of Dimethyl Carbonate from Methanol and Carbon Dioxide Catalyzed by Potassium Hydroxide under Mild Conditions

The synthesis of dimethyl carbonate （DMC） from methanol and carbon dioxide using potassium hydroxide as catalyst in the presence of CH3I and the effect of ionic liquid on the reaction were investigated. The results showed that KOH is an effective catalyst; the high selectivity and raised yield of DMC formation under mild conditions were achieved. However, the addition of the ionic liquid, l-ethyl-3-methylimidazolium bromide （emimBr）, can evidently accelerate the conversion of methanol and yield of the product.