Medium energy ion irradiation of Ge surface – search for a better understanding of the surface nano‐patterning

We report the morphological changes on Ge surfaces upon 50 keV Ar⁺ and 100 keV Kr⁺ beam irradiation at 60° angle of incidence. The Ge surfaces having three different amorphous–crystalline (a/c) interfaces achieved by the pre‐irradiation of 50 keV Ar⁺ beam at 0°, 30° and 60° with a constant fluence of 5 × 10¹⁶ ions/cm² were further processed by the same beam at higher fluences viz. 3 × 10¹⁷, 5 × 10¹⁷, 7 × 10¹⁷ and 9 × 10¹⁷ ions/cm² to understand the mechanism of nano‐scale surface patterning. The Kr⁺ beam irradiation was carried out only on three fresh Ge surfaces with ion fluences of 3 × 10¹⁷, 5 × 10¹⁷ and 9 × 10¹⁷ ions/cm² to compare the influence of projectile mass on surface patterning. Irrespective of the depth of a/c interface, the nanoscale surface patterning was completely missing on Ge surface with Ar⁺ beam irradiation. However, the surface patterning was evidenced upon Kr⁺ beam irradiation with similar ion fluences. The wavelength and the amplitude of the ripples were found to increase with increasing ion fluence. In the paper, the mass redistribution at a/c interface, the incompressible solid flow through amorphous layer, the angular distribution of sputtering/backscattering yields and the generation of non‐uniform stress across the amorphous layer are discussed, particularly in analogy with low energy experiments, to get better understanding of the mechanism of nanoscale surface patterning by the ion beams. Copyright © 2016 John Wiley & Sons, Ltd.     

液-固相体系中以聚(N-乙烯基咪唑)为非均相碱性催化剂在超声波照射和无溶剂条件下催化不同醛和酮羟醛缩合(英文)

An ultrasound‐assisted aldol condensation reaction has been developed for a range of ketones with a variety of aromatic aldehydes using poly(N‐vinylimidazole) as a solid base catalyst in a liquid‐solid system. The catalyst can be recovered by simple filtration and reused at least 10 times without any significant reduction in its activity. The reaction is also amenable to the large scale, making the procedure potentially useful for industrial applications.     

N-Sulfonic acid poly(4-vinylpyridinium) chloride as a highly effcient and reusable catalyst for the Biginelli reaction简

A mild, simple and efficient procedure for the preparation of 3,4-dihydropyrimidin-2（1H）-ones and -thiones is described using N-sulfonic acid poly（4-vinylpyridinium） chloride （NSPVPC） as a heterogeneous and efficient catalyst under solvent-free conditions. Simple methodologies, easy work-up procedure, easy preparation of the catalyst, excellent yields and very short reaction times are among the other advantages of this work. Further, the catalyst can be reused and recovered for several times without significant decrease in its activity.     

Synthesis,characterization and crystal structure of a dioxomolybdenum(VI) complex with a N,O type bidentate Schiff base ligand as a catalyst for homogeneous oxidation of olefins

The synthesis of a Mo(VI) Schiff base complex, cis-[MoO₂{(4,6-bis(tert-butyl)-2-{(benzyl)iminomethyl}phenolate)₂}], cis-[MoO₂(L)₂] where L = 4,6-bis(tert-butyl)-2-{(benzyl)iminomethyl}phenol, derived from benzylamine and 3,5-di-tert-butylsalycilaldehyde is reported. Full characterization of this complex was accomplished with elemental analyses, spectroscopic studies (NMR, IR and electronic) and X-ray structure analysis. This complex was tested as a catalyst for the homogeneous oxidation of olefins. The Mo(VI) complex is catalytically active for the epoxidation of aliphatic substrates at 80 °C, yielding the epoxide as the sole product in yields up to 100% and turnover numbers up to 5000. Under the optimized conditions styrene was oxidized in an 81% conversion to produce styrene oxide, benzaldehyde, and acetophenone.     

A pinacol boronate caged NIAD-4 derivative as a near-infrared fluorescent probe for fast and selective detection of hypochlorous acid

A pinacol boronate caged NIAD-4 derivative was demonstrated to be a near-infrared fluorescent probe for fast and selective detection of hypochlorite over other ROS species.     

Preparation of core/shell/shell CoFe2O4/OCMC/Cu (BDC) nanostructure as a magnetically heterogeneous catalyst for the synthesis of substituted xanthenes,quinazolines and acridines under ultrasonic irradiation

Highly efficient synthesized magnetic cobalt ferrite nanoparticles supported on OCMC@Cu (BDC) was utilized in the preparation of biologically active heterocyclic compounds through one-pot three-component reactions between of aldehydes, dimedone, aryl amines/2-naphthol/urea under ultrasonic irradiation. This method has various advantages including excellent yields, little catalyst loading, simple procedure, facile catalyst separation, short reaction times, eco-friendly approach and simple purification. The catalyst was characterized by various spectroscopy methods such as fourier-transform infrared (FT-IR), energy-dispersive X-ray (EDX), scanning electron microscope (SEM), X-ray diffraction (XRD) and N₂ adsorption–desorption isotherm (BET). Furthermore, the heterocyclic compounds were characterized by spectral techniques. The nanocomposite was simply separated byusing an external magnet, and it can be recycled several times without significant loss of activity.     

可重复使用的新型催化剂的合成、表征及在绿色条件下催化Suzuki和Heck反应:锚合在磁性纳米多孔的MCM-41上Pd(0)希夫碱络合物

将Pd希夫碱络合物固定在磁性的MCM-41表面上,做为环境友好且可循环使用的新型多相纳米催化剂,并采用红外光谱、振动探针式磁强计、能量散射谱、透射电镜、扫描电镜、热重、电感耦合等离子体发射光谱和X-射线衍射等对其进行了全面的表征.然后将该催化剂用于以PEG为绿色溶剂的一步法Suzuki和Heck合成反应中,均以较高收率得到目标产物.该法主要优点为反应时间短、反应条件绿色友好、操作简便、无需使用有毒的有机溶剂、催化剂使用量低,且底物适用性广.更为重要的是,通过外部磁场即可方便地将催化剂从反应混合物中分离出来,可重复使用数次而活性和稳定性未见明显下降.     

H3PW12O40@nano‐ZnO: An efficient,recyclable, and eco‐friendly catalyst for the green synthesis of novel benzo[a]pyrimido[5′,4′:5,6]pyrano[2,3‐c]phenazines via sequential multicomponent reactions under microwave irradiation

A simple, efficient, single‐pot synthesis of novel heteroaryl‐substituted benzo[a]pyrimido[5′,4′:5,6]pyrano[2,3‐c]phenazines has been developed via initial Knoevenagel, subsequent Michael, and final heterocyclization reactions of 2‐hydroxynaphthalene‐1,4‐dione, o‐phenylenediamine, aromatic aldehydes, and barbituric acid in the presence of H₃PW₁₂O₄₀@nano‐ZnO as a recyclable heterogeneous catalyst in EtOH under microwave irradiation (MWI). This sequential green process with several advantages, such as operational simplicity, high yield, low cost, easy handling, eco‐friendliness and reusability of the catalyst, absence of any tedious work‐up or purification, and avoidance of hazardous or toxic reagents/catalysts/solvents, opens an effective and convenient way to pyrano‐functionalized benzophenazine systems, which are promising compounds for different biomedical applications.     

A simple and sensitive HPLC-fluorescence method for quantification of MDMA and MDA in blood with 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) as a label

A sensitive high-performance liquid chromatographic method with fluorescence detection to determine 3,4-methylenedioxymethamphethamine (MDMA) and 3,4-methylenedioxyamphethamine (MDA) in human and rat whole blood or plasma samples was developed by using 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) as a label. MDMA and MDA in a small amount of blood sample (ca 100 microL) were extracted by liquid-liquid extraction with ethyl acetate, and were derivatized with DIB-Cl under mild conditions (10 min at room temperature). A good separation of DIB-derivatives could be achieved within 45 min using a commercially available ODS column with an isocratic eluent of 10 mM citric acid-20 mM Na(2)HPO(4) aqueous buffer (pH 4.0)-CH(3)CN-CH(3)OH (50:45:5, v/v/v %). The calibration curves prepared with 1-methyl-3-phenylpropylamine (MPPA) as an internal standard showed good linearity (r = 0.999) with 0.36-0.83 ng/mL detection limit at a signal-to-noise ratio of 3. MDMA and MDA in rat whole blood could be monitored for 6 h after a single administration of MDMA (2.2 mg/kg, i.p.). The pharmacokinetic parameters for MDMA and MDA obtained by triplicate measurements were 426 +/- 23 and 39 +/- 6 ng/mL (C(max)), 20 +/- 5 and 100 +/- 10 min (T(max)), respectively.     

N-磺酸基聚(4-乙烯吡啶)硫酸氢铵作为新型、高效、可重复使用的固体酸催化剂用于无溶剂条件下酰化反应(英文)

N-Sulfonic acid poly(4-vinylpyridinum) hydrogen sulfate has been developed as a recyclable solid acid catalyst for the acetylation of alcohols, phenols, thiols, and amines, as well as the 1,1- diacetylation of aldehydes under solvent-free conditions at room temperature. The acetylated products were formed in good to excellent yields over short reaction times, and the catalyst could be readily recovered by filtration and used several times without any discernible loss in activity. The hydrogen sulfate anion of the catalytic system was found to play a critical role in enhancing the reaction time and yield of the acetylation reaction.     

Selective and sensitive extraction spectrophotometric method for the determination of vanadium (V) as a mixed ligand complex withN-phenyl benzohydroxamic acid and 4-(2-pyridylazo)resorcinol in non-aqueous media

A selective, sensitive and direct method for the spectrophotometric determination of vanadium in steels is developed in which vanadium is extracted withN-phenyl benzohydroxamic acid (PBHA) into chloroform from 5M hydrochloric acid medium followed by colour development by addition of 4-(2-pyridylazo)resorcinol (PAR) inN,N-dimethyl formamide (DMF). The vanadium(V)-PBHA-PAR mixed ligand complex shows maximum absorbance at 560 nm with a molar absorptivity 3.6 × 10⁴ l mol^–1 cm^–1 and obeys Beer's law up to 2.0 g/ml of vanadium. The composition of the mixed ligand complex is determined by Job's method of continuous variations which revealed a 1 1 1 ratio for V(V) PBHA PAR. This method can be directly applied for the determination of vanadium in steels, while in the case of titanium base alloys, after separation of titanium matrix it gives good results even at 50–200 g of vanadium per gram level.     

Full-wave analysis of stripping chronopotentiograms at scanned deposition potential (SSCP) as a tool for heavy metal speciation: Theoretical development and application to Cd(II)-phthalate and Cd(II)-iodide systems

A new mathematical treatment has been developed and implemented in an EXCEL spreadsheet in order to determine average equilibrium functions from the full set of data measured by scanning stripping chronopotentiometry (SSCP) in solutions containing different proportions of heavy metal ions and small-sized ligands. It has been applied to the experimental systems Cd(II)-phthalate and Cd(II)-iodide as models of complexation in the absence and in the presence of electrodic adsorption, respectively. The good agreement between the complexation parameters determined in this way, those predicted from literature data and those obtained using a cadmium ion selective electrode (ISE) confirms the validity of the proposed methodology and encourages its further refining for the analysis of macromolecular and heterogeneous systems.     

Functionalization of superparamagnetic Fe3O4@SiO2 nanoparticles with a Cu(II) binuclear Schiff base complex as an efficient and reusable nanomagnetic catalyst for N‐arylation of α‐amino acids and nitrogen‐containing heterocycles with aryl halides

Fe₃O₄@SiO₂ nanoparticles was functionalized with a binuclear Schiff base Cu(II)‐complex (Fe₃O₄@SiO₂/Schiff base‐Cu(II) NPs) and used as an effective magnetic hetereogeneous nanocatalyst for the N‐arylation of α‐amino acids and nitrogen‐containig heterocycles. The catalyst, Fe₃O₄@SiO₂/Schiff base‐Cu(II) NPs, was characterized by Fourier transform infrared (FTIR) and ultraviolet‐visible (UV‐vis) analyses step by step. Size, morphology, and size distribution of the nanocatalyst were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scatterings (DLS) analyses, respectively. The structure of Fe₃O₄ nanoparticles was checked by X‐ray diffraction (XRD) technique. Furthermore, the magnetic properties of the nanocatalyst were investigated by vibrating sample magnetometer (VSM) analysis. Loading content as well as leaching amounts of copper supported by the catalyst was measured by inductive coupled plasma (ICP) analysis. Also, thermal studies of the nanocatalyst was studied by thermal gravimetric analysis (TGA) instrument. X‐ray photoelectron spectroscopy (XPS) analysis of the catalyst revealed that the copper sites are in +2 oxidation state. The Fe₃O₄@SiO₂/Schiff base‐Cu(II) complex was found to be an effective catalyst for C–N cross‐coupling reactions, which high to excellent yields were achieved for α‐amino acids as well as N‐hetereocyclic compounds. Easy recoverability of the catalyst by an external magnet, reusability up to eight runs without significant loss of activity, and its well stability during the reaction are among the other highlights of this catalyst.     

Isatin‐SO3H coated on amino propyl modified magnetic nanoparticles (Fe3O4@APTES@isatin‐SO3H) as a recyclable magnetic nanoparticle for the simple and rapid synthesis of pyrano[2,3‐d] pyrimidines derivatives

Isatin‐SO₃H coated on amino propyl modified magnetic nanoparticles (Fe₃O₄@APTES@isatin‐SO₃H) is found to be a novel, efficient, and reusable magnetic nanocatalyst, and characterized by FT‐IR, SEM, TEM, XRD, EDX, VSM, and TGA analysis. The magnetic nanocatalyst demonstrated outstanding performance in synthesis of pyrano[2,3‐d] pyrimidines derivatives via one‐pot three‐component reaction of various aromatic aldehydes 1, malononitrile 2, and barbituric acid 3 under reflux conditions in mixture of H₂O:EtOH (1:1) as solvent. Easy workup procedure, short reaction time, high yield, simple preparation and easy recovery of the catalyst, mild reaction conditions are some advantages of this work.