纳米氧化镍的制备及其电容特性研究

Nano-nickel oxide was synthesized by chemical deposition of nano-nickel hydroxide followed by heat-treatment in air at 300 ℃. The structure of the sample was studied by XRD, TEM, etc. The electrochemical characteristics of the sample were studied by Cyclic Voltammetry and constant current charge/discharge. The results showed that the structure of nickel oxide was cubic and the shape was acicular. The specific capacitance of the nickel oxide was about 130 F·g^-1 in the 9.0 mol·L^-1 KOH solution. The effects of scan speed, heating temperature and cycling on the specific capacitance were discussed.     

矿化剂浓度对水热法合成氧化锌晶体的影响

In this paper different shapes of ZnO crystals were synthesized by hydrothermal method when different con-centrations of mineralizer were used. When KOH was less than 2mol·L^-1 and the fill factor was approximately 35% at 350℃, ZnO crystals were synthesized with size of several hundred nanometer or several micron. The shapes of crystals were hexagonal cones. When 3mol·L^-1 KOH was used as mineralize at 350℃ and the fill factor was approximately 35%, the crystals with many different sizes were synthesized, the size of maximal crystal was over 100 micron, the small-size crystals were only several micron. When mineralizer KOH was less than 1mol·L^-1 and the fill factor was approximately 35% at 430℃, ZnO crystals were synthesized with size of several hundred nanometer or several micron. The shapes of crystals were hexagonal cones. When 1.5mol·L^-1 KOH or 2mol·L^-1 KOH was used as mineralize at 430℃ and the fill factor was approximately 35%, the high quality and hexagonal prism crystals were synthesized with many different sizes, the size of maximal crystal was over 100 mi-cron, the small-size crystal was only several micron. Especially when 3mol·L^-1 KOH was used as mineralize at 430℃ and the fill factor was approximately 35%, the high quality and hexagonal prism crystals were synthesized with size of 1mm along c axis. The exposed faces were hexagonal faces m{1010}, hexagonal cone faces p{1011}, negative polar faces O{0001}. In addition, many crystals with the shape of hexagonal cone and in several micron to 50 μm of size were present. The exposed faces were hexagonal cone faces p{1011}, negative polar faces {0001}.     

超声化学法制备树枝状纳米银的研究

Nanostructured silver dendrites were synthesized by using sonochemical method from an aqueous solution of AgNO₃ in the presence of isopropanol as reducing agent and polyethylene glycol (PEG) as disperser. The silver nanostructures were characterized by using TEM， XRD and EDS analysis. The effects of reducing agents， dispersers， concentration of AgNO₃ on the silver dendrites nanostructures were also invetigated. A well-defined nanostructured silver dendrite was prepared by ultrsonic irradiation of the aqueous solution of 0.04 mol·L^-1 silver nitrate， 4.00 mol·L^-1 isopropanol and 0.04 mol·L^-1 PEG400 for 1 h.     

纳米氧化锰电极材料的制备和电容特性研究

The nano-MnO₂ as active electrode material for supercapacitor was synthesized by solid-state reaction between KMnO₄ and manganese acetate at room temperature. The products annealed at 100 ℃ and 200 ℃ were characterized by XRD and TEM. The results showed the sample annealed at 100 ℃ was poorly crystallized phase with an average grain size of <20 nm. Electrochemical performances of manganese oxide electrode were investigated by cyclic voltammetry and constant current charge/discharge. The manganese oxide electrode annealed at 100 ℃ in 1 mol·L^-1 Na₂SO₄ aqueous electrolyte exhibited excellent capacitive behavior between -0.2 and +0.8 V (vs SCE). By 5 mA and 10 mA constant current charge/discharge, the nano-MnO₂ annealed at 100 ℃ can provide a specific capacitance of 158.5 F·g^-1 and 151.2 F·g^-1, respectively.     

明胶基多孔碳球电极材料的制备及电化学性能研究

Gelatin-based porous carbon beads have been fabricated from gelatin micro-spheres by means of solidification, carbonization and chemical activation with KOH. The physical properties of gelatin-based porous carbon beads were studied by a t-plot method based on N₂ adsorption isotherms. The gelatin-based porous carbon beads activated at 800 ℃ exhibited the largest specific surface area and resulted in the highest capacitance. Carbon/carbon super-capacitors cells assembled with the electrode materials in 1.0 mol·L^-1 NEt₄BF₄ / acetonitrile electrolyte have also been studied. The electrochemical properties of gelatin-based porous carbon beads electrode were studied by using constant-current discharge tests. The results indicate that the gelatin-based porous carbon beads electrode is with good cycling stability and specific capacitance of 119.8 F·g^-1.     

ZnS准纳米棒的胶棉膜模板合成及其性能研究

ZnS Quasi-nanorods were successfully synthesized with artificial active membrane of celloidin as template by the cooperating effect of artificial active membrane and ethylenediamine. The results indicated that ZnS quasi-nanorods, which had a hexangular wurtzite structure, could be formed at room temperature with 0.1mol·L^-1 ZnSO₄ which added suitable template reagent ethylenediamine and 0.1mol·L^-1 Na₂S as reactants. The par-ticles＇ diameter was from 200nm to 500nm, and the average length was about 12μm. The photics property study showed that the product reserved the properties of IR permeation and fluorescent luminescence in bulk materials, and the UV-Vis spectrum showed that the furthest absorption peak was at 308nm having 42nm＇s blue-shift com-paring to ZnS bulk material, which indicated that the particles had obvious quantum size effect.     

利用微波法合成二氧化钛纳米管

Titania nanotubes were synthesized by microwave method. The effects of raw materials, reaction time, NaOH solution concentration, and microwave power were studied. The samples were investigated by means of TEM, XRD, ICP techniques. Titania nanotubes having a hollow structure with an opening end were synthesized in NaOH solution (9~11 mol·L^-1) heated by 195 W microwave for over 60 min. The length of the titania nanotubes was about 1 μm and the average diameter of the nanotubes was about 8~10 nm.     

有机溶液中电化学制备纳米MgTiO3

In a cell without separating the cathode and anode spaces, the precursor MgTi(OCH₂CH₃)_(6-y)(acac)_y of the mixed oxide MgTiO₃ was directly synthesized by electrochemical dissolution of titanium for 4 hours and then of magnesium for 1 hour 40 minutes at the current of 0.2 A in ethanol and acetyl-acetone solution. The nano- MgTiO₃ powder was prepared by a direct sol-gel process of the electrolyte solution under pH≈8.5 followed by washing, drying in vacuum for 24 h, and calcination at 500 ℃ for 2 h. IR and Raman spectroscopy, XRD, and TEM were used to investigate the structure of nano-MgTiO₃ and its precursor. The result suggested that it was more appropriate to control the temperature between 35～40 ℃ and the concentration of conductive additive (Bu₄N)Br at 0.04 mol·L^-1. The xerogel with an average particle size of 12 nm and the nano-MgTiO₃ of 20 nm was thus obtained in a high purity.     

有机体系中电合成纳米PbTiO3粉体及表征

The precursor PbTi(OCH₂CH₃)_6-y(acac)_y for the mixed oxide PbTiO₃was synthesized by electrochemical dissolution of Lead and Titanium with a 1∶2 electricity quality in ethanol and acetyl-acetone solution. Nano-sized PbTiO₃powder was prepared by drying and calcining the xerogel from a direct sol-gel hydrolyzation of the precursor solution under pH of 8.5. The FTIR, TG-DTA, XRD and TEM were employed to characterize the structure of the precursor and nano-sized PbTiO₃. The results showed that the optimized conditions for the preparation of nano-sized PbTiO₃ were the electrolysis of the Lead plate and Titanium plate at 50 ℃ and 40 ℃ respectively under 0.03mol·dm^-3Bu₄NBr solution. The nano-sized PbTiO₃prepared by electrolysis exhibited a dispersive structure with an average diameter of 10 to 15 nm.     

强烈阳极氧化法快速制备多孔氧化铝模板

In the electrolyte of oxalic acid/alcohol/aqueous solution, highly-ordered porous anodic aluminum oxide(AAO) template was fabricated by hard anodization. The surface morphology and the structure of AAO template were characterized by Field-Emission Scanning Electron Microscope(FE-SEM) and XRD, respectively. The effects of different factors including alcohol type, ratio of alcohol to water, and oxalic acid concentration on the ordering degree and pore diameter of AAO template were investigated. Under the glycol to water ratio of 1∶1(by volume) with an oxalic acid concentration of 0.5 mol·L^-1, and voltage at 160 V, the obtained AAO template was hexangular arrangement with pore diameter of 80 nm and pores spacing of 120 nm, the growth rate was 51.9 μm·h^-1.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

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 substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.