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.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.