均一形貌的ZnO纳米棒的制备及其光催化性能研究

ZnO nanorods were synthesized from high purity Zn granule by a vapor phase deposition in the Ar + O₂ gas. The products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The ZnO nanorods were typically 1～2 μm in length and 20～30 nm in diameter with an aspect ratio as high as 20. The UV absorption properties were detected and the results show that the ZnO nanorods have an extremely strong absorption at 200～380 nm wavelength. The results were good when the ZnO nanorods were used as photocatalyst.     

反相微乳液法合成SrTiO3纳米棒

SrTiO₃ nanorods were synthesized in cetanyl trimethyl ammonium bromide (CTAB) reverse microemulsion containing CTAB, n-hexanol, n-octane and water with Ba(OH)₂ as reactants. The effects of different conditions such as ω₀ [ω₀=n_H2O/ n_CTAB], aging time and the concentration of reactants on the formation of the nanorods were studied. Transmission electron microscope (TEM), electron diffraction (ED) and X-ray diffraction(XRD)were used to characterize the morphology and the structure of the synthesized nanorods. The results show that SrTiO₃ nanorods with a length of 260～2 000 nm and a diameter of 50～100 nm belonging to single crystal are single cubic system. The molar ratio of Sr to Ti of products is 1.0 as determinded by ICP.     

La2(CO3)3纳米线的微乳液法制备与表征

La₂(CO₃)₃ nanowires were prepared in the nonionic surfactant microemulsion(Triton X-100/cyclohexane/water)system. Transmission electron microscopy (TEM) and selected area electronic diffraction (SAED) were used to characterize the shape and size of the products. The results showed that the pH value and concentration of mother solution, temperature and aging time all could affect the morphology and size of the La₂(CO₃)₃ nanowires. The lengths of the nanowires were more than 10 μm and the diameters were in the range of 30～200 nm.     

一种制备大量氧化锌纳米管的简单方法(英)

ZnO nanotubes were synthesized in large scale by thermal decomposition of the precursors obtained via chemical reaction between Zn(CH₃COO)₂·2H₂O and NaHCO₃ in the presence of surfactant sodium dodecyl sulfate (SDS). The inner diameters of the tubes were in the range of 80～100 nm, and outer diameters in the range of 160～260 nm with lengths up to a few micrometers. The products were characterized with XRD, TEM, and SEM.     

Li4Ti5O12溶胶-凝胶法合成及其机理研究

The precursors of Li₄Ti₅O₁₂ were prepared from tetrabutyl titanate and lithium acetate by sol-gel process. The Li₄Ti₅O₁₂ samples were synthesized by calcining the gel precursors at 400～900 ℃ in air for 6～20 h. Its reaction mechanism was investigated by infrared spectroscopy(IR), thermogravimetry(TG) and X-ray diffraction(XRD). The effects of sinter-temperature, calcination-time and thermal-treatment for the products were discussed. The samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM). The results showed that the single-phase products were obtained by calcining the gel precursors at 800 ℃ in air for 20 h, the sinter-temperature was lower than that of solid-state method, the particles were narrowly distributed, well crystallized with a size range from 0.3μm to 0.5 μm.     

锂离子电池正极材料LiMn2O4的合成与晶体结构（英）

Spinel LiMn₂O₄ powders were prepared using two-step synthesis method consisting of solid-state reaction method and citrate modified sol-gel method. The effects of the calcination temperature and the Li/Mn ratio of raw materials were studied on the physicochemical and electrochemical properties of the spinel LiMn₂O₄ powders, such as crystallinity, lattice constant and density. The title compound was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Polycrystalline LiMn₂O₄ powers calcined at 750 ℃ were found to be composed of very uniformly-sized microcrystal with an average particle size of 300 nm. The improvement in electrochemical properties was mainly attributed to the process of re-grinding by absolute alcohol.     

氧化锌纳米棒的制备和生长机理研究

ZnO nanorods are prepared by different assistants (cetyltrimethylammonium bromide，trisodium citrate and ethylene diamine anhydrous) favored hydrothermal synthesis with Zn(OH)₂ colloid as the precursor. The samples are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that the as-synthesized ZnO nanorods are of uniform size with 25 nm in diameter and 200～300 nm in length. The effects of the different assistants to the morphology, size and mechanism of nano-ZnO are discussed.     

含氟体系中DDR型分子筛的合成

DDR (Deca-dodecasil 3R) zeolite was synthesized hydrothermally in fluoride medium. The effects of synthesis conditions including the amount of KF, different fluoride sources and seeds on crystallization of DDR zeolite were investigated. The as-synthesized DDR zeolite samples were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results demonstrated that DDR crystallization was strongly affected by n_KF/n_SiO2, fluoride sources and seeds. Pure DDR zeolite could be successfully obtained in n_KF/n_SiO2 range of 0.5～1 after 9 days of hydrothermal synthesis. The synthesis time was reduced to 1 day by adding small amount of seeds with yield approaching 100%.     

针状TiO2锐钛矿晶粒溶胶的制备、结构及形成机理研究

The PTA sol was prepared using titanyl sulfate(TiOSO₄), peroxide (H₂O₂) and ammonia (NH₃·H₂O) as raw materials. The semitransparent, light yellow AS(autoclaved sol) with ultra-fine needle-like anatase crystals was synthesized by autoclaving the PTA sol at 80～100 ℃ for different times. The anatase crystals were needle-like and 80 nm in length, 20～30 nm in diameter. The FTIR, XRD, SEM were used to analyse the chemical structure, properties of the AS and influencing factors during the sol preparation. The mechanism model of the AS formation was established based on the inorganic and crystal structural chemistry. The PTA molecules were decomposed to form Ti⁴⁺ under hydrothermal conditions and the Ti⁴⁺ were hydrated with water to get [Ti(OH)₄(OH₂)₂]⁰, a growing units of the anatase crystals. The appearance of the needle-like anatase crystals and the anatase precipitate are also explained in this paper.     

SnO2/ 石墨复合材料作为锂离子电池负极材料研究

Nano-scale SnO₂ powders were prepared by hydrolyzation. Graphite was poured into the SnCl₄ solution during hydrolyzation. After drying and calcining at 360 ℃, the negative electrode composite material of nanosized SnO₂ and graphite was obtained. The composite materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average crystallite size was in the range of 15～20 nm. Electrochemical lithium insertion/extraction was studied preliminarily on the obtained composite. The discharge capacity of nanosized SnO₂ / graphite composite was found to have a high electrochemical reversible capacity for Li-ion insertion and extraction, which possessed the advantages of both higher discharge capacity of SnO₂ and lower discharge potential of graphite. In addition, the cycle capability was also improved due to the inhibiting effect of the composite against pulverization and agglomeration to a certain extent during Li-ion insertion and extraction.     

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%.     

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.     

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.     

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.     

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.     

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.     

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.     

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.