羟基功能化离子液体中Ag纳米材料的制备及结构表征

Ag nanoparticles were prepared using hydroxyl-functionalized ionic liquids as reductant and reaction medium. Nanoparticles with different particle sizes were obtained by using ionic liquids with different structures, while nanorods were harvested when the reaction temperature was increased. The materials obtained were investigated by XRD and TEM. The results indicate that the crystal is in face-centred cubic structure for both of Ag nanoparticles and nanorods, and the diameter of Ag nanoparticles prepared in 1-ethoxyl-3-methyl imidazolium tetrafluoroborate ([C₂OHmim]BF₄), 1-(4′-hydroxyl)butyl-3-methyl imidazolium tetrafluoroborate ([C₄OHmim]BF₄) and 1-(6′-hydroxyl)hexyl-3-methyl imidazolium tetrafluoroborate ([C₆OHmim]BF₄) ionic liquid is about 25, 15 and 10 nm, respectively. And the diameter of Ag nanorods is about 200 nm and 2 μm in length. Finally, the formation mechanism of Ag nanoparticles and nanorods is proposed.     

羧基功能化离子液体修饰Pd纳米微粒的制备及结构表征

1-methyl-3-(ω-carboxyl)decyl imidazolium bromine ([C₁₁OOHmim]Br) ionic liquid was synthesized and [C₁₁OOHmim]Br modified Pd nanoparticles were prepared in solution. The morphology and structure of Pd nanoparticles were investigated by IR, TEM, XRD, XPS. The results indicated that the Pd nanoparticles were face-centered cubic structure and the diameter was between 10～30 nm. [C₁₁OOHmim]Br was connected to the surface of Pd nanoparticles by carboxyl and Pd nanoparticles with different sizes could be obtained by varying the amount of the modifier.     

Bronsted Acidic Ionic Liquids as Efficient Catalysts and Mediums for the Synthesis of Half-esters:Structure-catalytic Selectivity Relationship

Bronsted acidic ionic liquids based on imidazolium cation were employed as efficient catalysts and mediums for the ring opening of phthalic anhydride to synthesize half-esters. Good yields, short reaction time and mild reaction condition were achieved. Lower acidity of ionic liquid resulted in higher catalytic selectivity in the synthesis of half-esters. The minimum-energy geometries of sulfonic acid-functionalized ionic liquids based on imidazolium cation revealed that their acidities and catalytic selectivity in the synthesis of half-esters were related to their structures.     

Highly sensitive determination of trace potassium ion in serum using the resonance light scattering technique with sodium tetraphenylboron

A resonance light scattering technique has been developed in order to determine potassium ion in serum. Potassium ion was found to bind the tetraphenylboronate anion [(C₆H₅)₄B]⁻ in acetate buffer (pH 8.0) in the presence of sodium dodecyl benzene sulfonate as a stabilizer, forming the B(C₆H₅)₄-K aggregate which produces intense resonance scattering light. Effects of factors such as acidity, ionic strength and interferents on the RLS of B(C₆H₅)₄-K were investigated. The solution pH close to neutral facilitates the production of RLS, and few biologically relevant species interfere in the determination of potassium ion. The resonance scattering light intensity at the maximum peak of 567 nm was linear to the concentration of potassium ion in the range of 0.2–2.0 μg mL⁻¹ with a detection limit of 20.0 ng mL⁻¹. The method was applied to determine trace amounts of potassium ion in serum and showed high sensitivity and accuracy compared with the clinically used ion-selective electrode method.     

BrФnsted Acidic Ionic Liquids as Efficient Catalysts and Mediums for the Synthesis of Half-esters: Structure-catalytic Selectivity Relationship

BrФnsted acidic ionic liquids based on imidazolium cation were employed as efficient catalysts and mediums for the ring opening of phthalic anhydride to synthesize half-esters. Good yields, short reaction time and mild reaction condition were achieved. Lower acidity of ionic liquid resulted in higher catalytic selectivity in the synthesis of half-esters. The minimum-energy geometries of sulfonic acid-functionalized ionic liquids based on imidazolium cation revealed that their acidities and catalytic selectivity in the synthesis of half-esters were related to their structures.     

Pt3Co核-Pt壳型纳米粒子的制备及磁性

Pt₃Co alloy nanoparticles were prepared by the reduction of H₂PtCl₆ and Co(OOCCH₃)₂ using NaBH₄ as a reducing agent. The Pt₃Co core-Pt shell nanoparticles (Pt₃Co@Pt) were synthesized using hydrogen absorption reduction and characterized by plasma-atomic emission spectrometry (ICP), transmission electron microscopy (TEM), X-ray diffraction (XRD) and SQUID magnetometer. The results show that average size of Pt₃Co@Pt nanoparticles is 3.6 nm with a standard deviation of 0.9 nm. Heating Pt₃Co nanoparticles in air at 700 ℃ for 1 h, Co in Pt₃Co nanoparticles was oxidized to Co₃O₄ and CoO; while no oxidation tendency was detected for Pt₃Co@Pt nanoparticles. The crystallize structure of Pt₃Co@Pt changed from the face centered cube (fcc) to the face centered tetragonal (fct) after the heating treatment. The coercivity of the heated Pt₃Co@Pt reached to 276 Oe at room temperature.     

Characteristics of Pd/Nafion electrodes prepared by an impregnation-reduction method in sensing hydrogen

The influences of reductant concentration and Pd loading on the response and recovery times and the sensitivity in detecting hydrogen of Pd/Nafion electrodes prepared by an impregnation-reduction method were investigated in this study. The Pd/Nafion electrodes with a Pd loading of 6.90 mg/cm², obtained at 0.006 M Pd(NH₃)₄Cl₂ and 0.06 M NaBH₄, show the maximum sensitivity of 0.0519 μA/ppm in the H₂ concentration range 0–4410 ppm. However, The Pd/Nafion electrodes with a Pd loading of 11.42 mg/cm², obtained at 0.01 M Pd(NH₃)₄Cl₂ and 0.06 M NaBH₄, show the fastest response and recovery speed in sensing hydrogen. Generally, the response time decreases with an increase of the hydrogen concentration, but the recovery time increases with an increase of the hydrogen concentration. A sensing model is also proposed to illustrate the sensing phenomenon. Electronic Publication     

共价键连卟啉-富勒烯化合物的合成与表征

The covalently linked porphyrin-fullerene dyads were synthesized. The ligand 5-[4′-(4″-Phenoxybutoxy)phenyl]-N-(2-methyl)fulleropyrrolidine-10,15,20-tri-(p-methoxyphenyl)porphyrin (H₂P-C₆₀) was synthesized by 1,3 dipolar cycloaddition reaction with C₆₀, sarcosine and H₂P-CHO. The zinc porphyrin-fullerene was prepared by metalation of H₂P-C₆₀ and zinc acetate. The compounds were characterized by meams of IR, UV-Vis, ESI-MS, elemental analysis, and ¹H NMR.     

V2O3纳米粉末的固相反应合成(英)

Vanadium sesquioxide (V₂O₃) nanopowder was successfully prepared by the solid phase reaction of the mixture of vanadyl hydroxide (VO(OH)₂) and ammonium chloride (NH₄Cl) at 500 ℃. The as-obtained samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). V₂O₃ nanoparticles were well dispersed and displayed sphere-like particles with diameters in the range of 30～50 nm.     

Evaluation of Retention Factors for Nine Solutes with Ionic Liquid Additives via Linear Solvation Energy Relationships

<正>A linear solvation energy relationships(LSERs) model was used to examine the fundamental chemical interactions governing the retention of 9 organic compounds on a C_(18) column by means of reversed-phase high performance liquid chromatography(RP-HPLC).Three ionic liquids,1-hexyl-3-methylimidazolium tetrafluoroborate ([Hmin][BF_4]),1-butyl-3-methylimidazolium tetrafluoroborate([Bmin][BF_4]) and 1-octyl-3-methylimidazolium tetrafluoroborate([OMIm][BF_4]) as additives,were added to a methanol-water mobile phase.The effects of these three ionic liquids additives on the retention of nine organic compounds were investigated,and a comparison between the predicted and experimental retention factors was made via the LSERs model,which indicated that the LSERs model could be used to reproduce the experimental retention factors of the solutes under different mobile phase conditions. It is also a useful tool for modeling the interactions of the solutes between the stationary and mobile phases and evaluating the retention characteristics of HPLC.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.     

Copper-catalyzed multicomponent reactions of 2-iodoanilines,benzylamines, and elemental sulfur toward 2-arylbenzothiazoles

A relatively cheap copper salt-catalyzed, three-component approach providing 2-arylbenzothiazoles in good to excellent yields from readily available 2-iodoanilines, benzylamines, and sulfur powder is reported. This methodology allows preparation of various classes of 2-arylbenzothiazoles and provides a general, reliable approach.