六方MoN的合成新路线

 在高温高压极端条件下利用CH₄Cl还原二氧化钼的方法合成了六方MoN。反应条件为：压力2 GPa,温度1 500 ℃,时间2 h。并利用XRD对合成产物进行了表征。经最小二乘法拟合后结果表明,该合成产物具有六方结构对称性,其晶格常数为a＝0.572 nm,c＝0.560 nm。经过对其衍射峰位和峰强进行拟合计算,并与实验结果进行比较, 结果表明 MoN 产物的空间群为P6₃/mmc,其中Mo原子位于2b (0, 0, 1/4)和6h (x, 2x, 1/4),x＝0.489。N原子位于2a (0, 0, 0)和6g (0.5, 0, 0)。所采用的方法具有反应条件易达到、反应时间短、反应产物单相性好等特点。     

Ultrasound assisted synthesis of delta-chloroesters from tetrahydrofuran and acyl chlorides in the presence of catalytic zinc dust

Sonication of acyl chlorides and dry tetrahydrofuran (THF) in the presence of catalytic amounts of zinc dust at 35 kHz gives delta-chloroesters in high yields.     

Sonochemical synthesis and characterization of new nanostructures cobalt(II) metal-organic complexes derived from the azo-coupling reaction of 4-amino benzoic acid with anthranilic acid,salicylaldehyde and 2-naphtol

Nanostructures of three new cobalt(II) complexes, (CoL₁)·0.5DMF·1.5MeOH (1), [H₂L₁ = 5-(4-Carboxy phenyl azo) anthranilic acid], (Co(L₂)₂)·1.5MeOH (2), [HL₂ = 5-(4-Carboxy phenyl azo) salicylaldehyde] and (Co(L₃)₂)·0.5 DMF·0.5MeOH (3), [HL₃ = 1-(4-Carboxy phenyl azo) 2-naphtol], have been synthesized by the reaction of H₂L₁, HL₂ and HL₃ with Co(OAc)₂·4H₂O through sonochemical process. Calcination of the nano-sized compounds 1–3 yield Co₃O₄ nanoparticles at 450 °C under air atmosphere. These nanostructures were characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). Thermal stability of compounds 1–3 was studied by thermogravimetric (TG) and differential thermal analyses (DTA).     

A new approach to charged-particle scattering in the presence of laser plus Coulomb-field

A new approach to charge-particle scattering in the presence of laser plus coulomb-field by using Fourier analysis technique is described. Explicit expressions for positive energy states and their asymptotic limits for the zero, one and two photon processes are evaluated exactly.     

A new approach to the synthesis of porphyrin-fullerene dyads

A new synthetic approach to porphyrin-fullerene dyads utilizing tetraphenylporphyrin (TPP) and three novel reactions (vicarious nucleophilic substitution, metathesis, and [4+2]-cycloaddition to fullerene) is described. 5-(4-Nitrophenyl)-10,15,20-triphenylporphyrin zinc complex reacts with the carbanion of chloromethyl para-tolyl sulphone (which bears a leaving group Cl at the carbanionic center), affording the nucleophilic substitution of hydrogen product containing a CH2SO2Tol group. The product obtained when alkylated with an alkyl halide (bearing an acetylenic function in the terminal position), followed by the cross-enyne metathesis reaction (with the use of an efficient ruthenium catalyst), resulted in the formation of a TPP-diene building block. Its Diels-Alder reaction with C60-fullerene led to the title dyad--a new artificial photosynthetic model. This method opens up the possibility for synthesis of dyads with variable distances between chromophores, depending on the type of the alkyl halides used.     

A new traveling wave phenomenon of Dictyostelium in the presence of cAMP

The emergence of wave patterns in chemical and biological systems is of interest for the understanding of development, differentiation, signaling, and other phenomena. In this work we report a new type of wave pattern - called the “global wave” - which was observed in populations of Dictyostelium discoideum cells exposed to an excess of cyclic adenosine- 3′, 5′- monophosphate (cAMP) added to the supporting agar. It has been found that the addition of different amounts of cAMP to the agar leads to important deviations from the standard course of aggregation: (i) the formation and propagation of a global wave that has not been observed before; (ii) the delayed onset or absence of cAMP waves patterning; (iii) an atypical mechanism of cells clustering; and (iv) a faster or incomplete developmental cycle. We suggest that the global wave is a chemotactic response of the Dictyostelium cells to a wave of the cAMP concentration.     

Combination of microwave reactions with fluorous separations in the palladium-catalyzed synthesis of aryl sulfides

Coupling of microwave reactions with fluorous separations can dramatically increase the efficiency of high-speed synthesis. Described in this paper is a fluorous synthesis of aryl sulfides by palladium-catalyzed cross-coupling of aryl perfluoroalkylsulfonates (C8F17O2SOAr) with thiols (RSH) under microwave irradiation. Fluorous solid-phase extractions (F-SPE) are employed for the purification of reaction mixtures. No fluorous solvents are involved in reaction and separation processes. The fluorous synthesis is further extended to the multi-step synthesis of substituted hydantoin and amide scaffolds.     

A mild and efficient one-pot synthesis of \upbeta -amino carbonyl compounds via Mannich reaction under ambient temperature condition

We have developed an efficient protocol for the synthesis of $\upbeta $ -amino carbonyl compounds using phenylboronic acid as effective and eco-friendly catalyst via one-pot three-component Mannich reaction. Excellent yields, mild reaction condition, and simple experimental work-up procedure are some of the advantages of this method, which makes it a useful protocol for the synthesis of $\upbeta $ -amino carbonyl compounds.     

A f acile,regioselective synthesis of novel 3-( N-phenylc arbox amide)pyr azolo[1,5- a]pyrimidine an alogs in the presence of KHSO$$_{}$$ in aqueous medi a assisted by ultr asound and their antib acteri al activities

An environmentally benign, simple, efficient, and convenient route is described for the synthesis of novel pyrazolo[1,5-a]pyrimidine derivatives under ultrasound irradiation. Condensation of aminopyrazole 5 with formylated active proton compounds (6, 8, E–G, 12, and 15) furnished pyrazolopyrimidine (7, 9, 10, 13, and 16) in high-to-excellent yields. In comparison with conventional methods, ultrasound irradiation offers several advantages, such as shorter reaction time, higher yields, milder conditions, and environmental friendliness. The reaction is clean with excellent yields and reduces the use of solvents. X-ray crystallographic study of compound 7c confirmed the regioselectivity of the reaction. The antibacterial profile of the newly synthesized compounds was evaluated by cup and saucer method.     

Facile synthesis of SERS active Ag nanoparticles in the presence of tri-n-octylphosphine sulfide

A facile and novel way was reported here for the synthesis of hydrophobic Ag nanoparticles (NPs), using AgNO₃, tri-n-octylphosphine (TOP) and sulfur (S) powder in process. TOP was used as solvent, reducing agent and stabilizer. S could chelate with excessive TOP to form trioctylphosphine sulfide (TOPS), which served as second capping agent. The hydrophobic Ag NPs could be transformed into hydrophilic state through ligand exchange. Furthermore, surface-enhanced Raman scattering (SERS) spectra of 4-aminothiophenol (4-ATP) were obtained on the hydrophobic and hydrophilic Ag NPs modified substrates, indicating that the as-synthesized Ag NPs had great potential for high sensitive optical detection applications.     

Measurement of the Ratio of Cumulative Spectra of Beta Particles from $${}^{{235}}$$ U and $${}^{{239}}$$ Pu Fission Products for Solving Problems of Reactor-Antineutrino Physics

Physics of Atomic Nuclei - The first cycle of measurements of the ratio of cumulative spectra of beta particles originating from the isotopes $${}^{235}$$ U and $${}^{239}$$ Pu undergoing...     

A new reaction: vacuum synthesis and characterization of IONO2 and IONO

The new reactions for preparing IONO₂ and IONO have been found. IONO₂ and IONO can be easily prepared in vacuum by the heterogeneous reactions of gaseous ICl over the solid powders AgNO₃(s) at the room temperature and AgNO₂(s) at 0(±1) °C which were loosely filled into the quartz inlet tube (about 1.5 cm inside diameter and 5 cm long) and supported on the quartz wool, respectively, and then are characterized well by the PES experiment and the ROVGF calculations.     

One-step synthesis and electrochemical behavior of LiMnO2 and its composite from MnO2 in the presence of glucose

LiMnO₂ and 0.23Li₂MnO₃·0.77LiMnO₂ were prepared by a convenient one-step solid-state reaction from MnO₂ using glucose as organic carbon resource. The crystal structure and morphology of the as-prepared materials was examined by X-ray powder diffraction and field emission scanning electron microscopy, respectively. The ration of Li to Mn was determined by means of atomic absorption spectrometry and the Li/Mn molar ratio in the products was 1.23. The electrochemical properties were investigated by charge-discharge test and electrochemical impedance measurements. The prepared composite material presented an initial discharge capacity of 45 mAh g^-1 and a good cycling performance with reversible capacity of 218 mAh g^-1 after 30 cycles. On the basis of the experimental results, the discharge efficiency of this composite material more than 100% was also discussed.     

Redispersion of dried gold nanorods in the presence of 6-amino-1-hexanethiol hydrochloride

Aggregates of phosphatidylcholine-passivated gold nanorods were prepared by the addition of hydrochloric acid in the presence of 6-amino-1-hexanethiol hydrochloride (AHT). The aggregates dried in vacuum formed a solid film showing a metallic gold color. In spite of the absence of the stable surface-wrapping agents, such as balky polymer or thiol-molecules that form stable self-organized films on a gold surface, the dried aggregates dispersed again in water. The redispersed gold nanorods in water did not form aggregates. If the dried nanorods were kept at room temperature for 24 h, they did not disperse in water again; however, at –30 °C, some of gold nanorods could be redispersed in water. At –80 °C, gold nanorods could be redispersed in water as colloidal nanoparticles even after 2 months. The phosphatidylcholine and AHT molecules on the nanorod surfaces contributed to the suppression of the contact of nanorods, which were in the metallic gold color films.     

A new route for the synthesis of nitrides: The solvothermal preparation of GaN

Abstract

A new solvothermal route for the synthesis of nitrides is proposed using liquid NH3 as solvent in supercritical conditions, Such a preparation method was applied to the synthesis of GaN using gallium metal as starting material.

GaN is a wide band-gap semi-conductor (3.4eV). It is a very attractive nitride due to its various applications in micro- and opto-electronics [1,2]. Consequently, many research groups are interested in synthesising GaN. Two methods have been principally developed:

(i) synthesis of thin films by epitaxy [3,4]

(ii) synthesis of bulk GaN by high pressure method [5,6].

The new proposed process leads to fine microcrystallites of GaN with the wurtzite-type structure. The chemical purity can be optimised versus the synthesis mechanism. The size and shape of the crystallites would be influenced by the nature of the nitriding additive and the thermodynamical conditions (pressure and temperature) used for the synthesis.     

Theoretical investigations on the Stark-Zeeman effect of the 2p~{}^{\mathsf 2}P3/2-level in 6Li for perpendicularly crossed fields

The splitting behaviour of the P_3/2 hyperfine structure levels is investigated in ⁶Li for homogeneous crossed electric and magnetic fields (Stark-Zeeman effect). This is done by diagonalizing the perturbation matrix comprising the hyperfine interaction, the electronic and nuclear magnetic interaction and the effective electric interaction obtained by transforming the quadratic Stark effect to a first order perturbation interaction. Symmetries are used to find analytic formulae for level shifts and crossing points if only one external field is present. A reflection symmetry unbroken with all three interactions present permits the decomposition of the 12 ×12 matrix into two 6 ×6 submatrices. The structure of energy eigenvalue surfaces epsilon_{F,M F}(B,E) of the two subsystems is found by numeric diagonalization of the perturbation matrix and is displayed in the ranges |B|< 1 mT kV/cm. The total angular momentum F = J + I  (J = 3/2, electronic angular momentum, I = 1, nuclear spin) and the magnetic quantum number M_F provide labels for all surfaces. All crossing points of the energy surfaces have been found. Adiabatic level transfer occurring in atoms traversing a sequence of crossed magnetic and electric fields is explained. Berry phases occur for cycles around some crossing points. Their presence or absence is explained.     

Formation of interfacial layer in Fe-polystyrene system during mechanochemical synthesis in the presence of alkyl surfactants

The structure of surface organic layers formed during the mechanical milling of Fe with polystyrene and alkyl surfactants is studied using NEXAFS and FT-IR spectroscopies. It is shown that the main constituents of the layers formed are condensed aromatic structures (products of the dehydrogenation of an organic medium) that contain covalently bound polystyrene fragments.