bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Characterization of a Polyaluminosilazane Precursor Prepared by Polymerizing Hexamethylcyclotrisilazane with Aluminum Acetylacetonate
Authors: Chu Zeng‐Yong , Feng Chun‐Xiang , Song Yong‐Cai , Li Xiao‐Dong , Xiao Jia‐Yu 
Published: September 2010

AbstractA new polyaluminosilazane precursor was prepared by polymerizing hexamethylcyclotrisilazane (HMCTS) with aluminum acetylacetonate and the structure of the precursor was characterized by FT‐IR and XPS analysis. Result shows that aluminum was incorporated mainly in form of Al—N bond. Oxygen was also detected and found that it was mainly bonded to silicon.
Synthesis and Characterization of PE‐g‐MA/MgAl‐LDH Exfoliation Nanocomposite via Solution Intercalation
Authors: Wei Chen, , Bao‐Jun Qu, 
Published: September 2010

AbstractAn organo‐modified MgAl‐layered double hydroxide (OMgAl‐LDH) was successfully exfoliated in the xylene solution of polyethylene‐grafted‐maleic anhydride (PE‐g‐MA) under re‐fluxing condition. A PE‐g‐MA/MgAl‐LDH exfoliation nanocomposite was formed after the precipitation of PE‐g‐MA from the dispersion system. The structure and thermal property of the PE‐g‐MA/MgAl‐LDH exfoliation nanocomposite were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetry analysis (TGA). The disappearance of d001 XRD peak of OMgAl‐LDH at 20 = 3.2° suggests that the MgAl hydroxide sheets are exfoliated in the nanocomposite. The TEM image shows that the MgAl hydroxide sheets of less than 70 nm in length or width are exfoliated and dispersed disorderly in PE‐g‐MA matrix. TGA profiles indicate that the PE‐g‐MA/MgAl‐LDH nanocomposite with 5 wt% OMgAl‐LDH loading shows a faster charring process in temperature range from 210 to 390 °C and a greater thermal stability beyond 390 °C than PE‐g‐MA does. The decomposition temperature of the nanocomposite is 25 °C higher than that of PE‐g‐MA as measured at 50% weight loss. The PE‐g‐MA/MgAl‐LDH nanocomposite is promising for application of flame‐retardant polymeric materials.
Prediction of Retention Time of Solutes under Linear Gradient Elution Conditions in RP‐HPLC
Authors: Geng‐Liang Yang , Bao‐Juan Tian , Yi Chen , De‐Xian Wang 
Published: September 2010

AbstractA model for predicting retention tune of solutes under linear gradient elution conditions has been established. In this model, the theoretical expressions under different elution modes were derived and tested with the retention behaviors of p‐hydroxybenzaldehyde, vanillin, biphenyl, phenanthrene in gradient elution. With taking into account the dwell time of the instrumental system, the theoretically predicted retention times agree well with those experimentally determined.
Asymmetric Reduction of Acetophenone O‐Methyloxime with Reagents Prepared from L‐Proline and Borane
Authors: Ping Du, , Zhen‐Liang Chen, , Lin Wang, , Hui Liu, , Dai‐Mo Chen, 
Published: September 2010

AbstractAsymmetric reduction of acetophenone O‐methyloxime with reagents in situ prepared from L‐proline and borane has been investigated. A series of conditions optimization were made, including an examination of the effect of the temperature of catalyst pretreatment, the temperature of reduction, the amount of borane, the additive, the solvent, the reducing agent and various chiral auxiliaries on the enantioselectivity. Under the optimal condition, (S)‐α‐phenylethylamine was obtained in 53% yield with 83.1% ee in the presence of 25 mol% L‐proline.
Synthesis of 2‐aminochromene derivatives catalyzed by KF/Al2O3
Authors: Wang Xiang‐Shan , Shi Da‐Qing , Tu Shu‐Jiang 
Published: September 2010

AbstractA series of 2‐aminochromene derivatives including 2‐amino‐benzo[h] chromene, 2‐amino‐benzo [f] chromene and 2‐aminopyrano [3, 2‐h] quinolin derivatives was synthesized from arylaldehyde, malononitrile or ethyl cyanoacetate and 1‐naphthol or 2‐naphthol or 8‐hydroxyquinoline in refluxing ethyl alcohol catalyzed by KF‐Al2O3. The structures were confirmed by X‐ray analysis.
Structure of tetra[β‐(1,2,4‐triazole‐l‐yl) propiophenone] dichloro nickel(II) solvate hexahydrate complex: [NiCl2(C2H2N3CH2CH2‐COPh)4]·6H2O
Authors: Jian Fang‐Fang , Xiao Hai‐Lian , Yu Bing , Jiao Kni 
Published: September 2010

AbstractThe mononuclear complex, [NiCl2 (trzCH2CH2COPh)4]·6H2O (trz =1,2,4‐triazole), was synthesized and its structure was determined by single crystal X‐ray determination. It crystallizes in the monoclinic system, space group P21/c, with lattice parameters: a = 0.80391(2) nm, b = 1.08215(2) tun, c = 2.90133(2) nm, β = 94.792 (1)° and Z = 2. Each nickel atom is coordinated by four N atoms of triazole from four β‐(1,2,4‐triazole‐1‐yl)propiophenone ligands and two chloride anions in trans arrangement with octahedral coordination geometry. In addition to the coordinating nickel complex, there are six uncoordinated water molecules. The Ni‐Cl distance is 0.24865(8) nm and the Ni‐N distances are in the range of 0.2072(2) to 0.2099(2) nm, respectively. In the solid state, the title compound forms three dimensional network structure through hydrogen bonds. The intermolecular hydrogen bonds connect the [NiCl2(C2H2N3CH2CH2COPh)4] and H2O moieties. The deep green crystals were also examined by elemental analysis, FT‐IR and UV spectra, which are in agreement with the structural data.
Synthesis and crystal structure of a new armed‐tetraazacrown ether and its liquid membrane transport of alkali metal cations
Authors: Ma Shu‐Lan , Zhu Wen‐Xiang , Dong Shu‐Jing , Guo Qian‐Ling , She Yuan‐Bin 
Published: September 2010

AbstractA new tetra‐N‐substituted tetraazacrown ether derivative, 4,7, 13,16‐tetra (2‐cyanobenzyl)‐1, 10‐dioxa‐4,7,13,16‐tetraazacyclooctadecane, C44H48N8O2, has been synthesized and structurally characterized. It crystallizes in the monoclinic system, space group P21/c with a = 1.1176(3) nm, b =2.1906(7) nm, c = 0.8430(3) nm, V = 2.0132(10) nm3, β = 102.740(5)°, Z =4, Dc = 1.189 g/cm3, final R1, = 0.0460, wR2 = 0.0803. The liquid membrane transports of alkali metal cations using the new macrocycle as the ion‐carrier were also studied. Compared with some macrocyclic ligands, our newly synthesized lig‐and showed a good selectivity ratio for Na+/Li+.
Synthesis, characterization of heterodinuclear Co‐Cu complex and its electrocatalytic activity towards O2 reduction: Implications for cytochrome c oxidase active site modeling
Authors: Lu Wei‐Bing , Wang Cun‐Xin , Zhou Xiao‐Hai , Ren Jian‐Guo 
Published: September 2010

AbstractA new dinucleating ligand consisting of a tetraphenylporphyrin derivative covalently linked with tris(2‐benzimidazylmethyl)‐amine and its homodinuclear Co‐Co and heterodinuclear Co‐Cu complexes were synthesized and spectroscopically characterized. The heterobimetallic cobalt‐copper complex bearing three benzimidazole ligands for copper, as cytochrome c oxidase active site model, was applied to the surface of glassy carbon electrode to show electrocatalytic activity for O2 reduction in aqueous solution at an acidity level close to physiological pH value. The kinetic parameters of this electrocatalytic process were obtained.
Capillary zone electrophoresis with amperometric detection for composition analysis of laminarin
Authors: Wang Qing‐Jiang , Ding Fei , Li Hui , He Pin‐Gang , Fang Yu‐Zhi 
Published: September 2010

AbstractThe composition of laminarin was firstly determined by analyzing its hydrolysis monosaccharides with capillary zone electrophoresis‐amperometric detection (CZE‐AD). Under the selected optimum conditions, fucose, galactose, glucose, mannose and xylose, which are hydrolysis products of laminarin, could be perfectly separated within 20 min and showed significant current responses at copper electrodes. The linear ranges of fucose, galactose and glucose were from 1.0 ± 10–6 to 2.0 ± 10–4 mol ± L−1, those of mannose and xylose were from 5.0 ± 10–6 to 2.0 ± 10–4 mol ± L−1, and their detection limits were at 10–7mol ± L−1 level (S/N = 3). The molar ratio of fucose, galactose, glucose, mannose and xylose in laminarin was 10.5: 2.8:1.0:7.3: 3.4 and the purity of this polysaccharide leached by the introduced leaching method was 95.7%. Compared to usual UV‐vis and other spectrometric methods, analyzing polysaccharide by this method has some merits of quickness, low‐volume sampling, simple instrumentation, high sensitivity and high reproducibility.
A new synthetic method of highly substituted cyclopentadienes from α, β‐unsaturated alkynones
Authors: Zheng Xing‐Liang , Zhang Yong‐Min 
Published: September 2010

AbstractPromoted by samarium diiodide in THF, the α, β‐unsaturated alkynones were reduced to afford intermolecular reductive coupling products. The multiply substituted cyclopentadienes were prepared conveniently in good yields.
Salen‐Mn(III)‐complex‐catalyzed oxidations of secondary alcohols
Authors: Sun Wei , Xia Chun‐Gu 
Published: September 2010

AbstractSecondary alcohols were catalytically oxidized with diacetoxyiodobenzene as oxidant in the presence of salen‐Mn(III) complex to afford the corresponding ketones, in up to 99% yield, using CH2Cl2 or water as reaction media.
Syntheses and crystal structures of lanthanide complexes of new 15‐membered macrocyclic ligands with three pendant acetato groups
Authors: Yao Ying‐Ming , Shen Qi , Wong Wing‐Tak 
Published: September 2010

AbstractTwo new 15‐membered functionalized macrocycles, dioxo‐polyazacycloalkanes with three pendant acetato groups, have been synthesized by the condensation reaction of DTP A dianhydride (DTPA = diethylenetriaminepentaacetic acid) with 1,2‐diaminopropane, (15‐DTPA‐1, 2‐pn), or 1, 2‐diaminocyclohexane, (15‐DTPA‐1,2‐cy). Their lanthanide complexes [Ln(15‐DTPA‐1, 2‐pn) (H2O)]2[Ln = Eu (1), Gd (2)] and [Ln(15‐DTPA‐1,2‐cy)(H2O)]2[Ln = Eu (3), Gd (4)] were also prepared. Single crystal X‐ray diffraction analyses of complexes 2 and 4 show that they have dimeric structures in solid state; each metal ion is nine‐coordinated in a distorted tricapped‐trigonal prism. In complex 4, the coexistence of two diastereoisomeric molecules in the crystal lattice was observed.
Synthesis and photocleaving DNA activity of 4′‐chlorobenzene‐sulfonyl chloride‐pyrrolecarboxamide hybrid compound
Authors: Tang Fei‐Li , Yuan Gu 
Published: September 2010

AbstractA 4′‐chlorobenzenesulfonyl chloride‐pyrrolecarboxamide hybrid compound was synthesized and its DNA cleaving activity was investigated using a pBluescript SK DNA under UV irradiation. This compound showed potent DNA cleaving activity.
Correlation between molecular structures and relative electrophoretic mobility in capillary electrophoresis: Alkylpyridines
Authors: Yao Xiao‐Jun , Fan Bo‐Tao , Doucet J. P. , Panaye A. , Liu Man‐Cang , Zhang Rui‐Sheng , Hu Zhi‐De 
Published: September 2010

AbstractThe quantitative relationship between relative electrophoretic mobility in capillary electrophoresis for a series of 31 closely related alkylpyridines and their molecular structures was studied by using CODESSA. According to the t‐test on the results, we found that the three most important descriptors affecting the mobility are the relative number of rings (NR), Min e‐n attraction for a C–‐N bond (MEN) and average complementary information index (ACIC). With these structure descriptors a good three‐parameter linear model was developed to correlate the mobility of these compounds with their structures. This model can not only correctly predict the migration behavior of these compounds, but also find the structural factors which are responsible for the migration behavior of these compounds, thus can help to explain the separation mechanism of these compounds. The method used in this work can also be extended to the mobility‐structure relationship research of other compounds.
Molecular simulations using spherical harmonics
Authors: Cai Wen‐Sheng , Xu Jia‐Wei , Shao Xue‐Guang , Maigret Bernard 
Published: September 2010

AbstractComputer‐aided drug design is to develop a chemical that binds to a target macromolecule known to play a key role in a disease state. In recognition of ligands by their protein receptors, molecular surfaces are often used because they represent the interacting part of molecules and they should reflex the complementarity between ligand and receptor. However, assessing the surface complementarity by searching all relative position of two surfaces is often computationally expensive. The complementarity of lobe‐hole is very important in protein‐ligand interactions. Spherical harmonic models based on expansions of spherical harmonic functions were used as a fingerprint to approximate the binding cavity and the ligand, respectively. This defines a new way to identify the complementarity between lobes and holes. The advantage of this method is that two spherical harmonic surfaces to be compared can be defined separately. This method can be used as a filter to eliminate candidates among a large number of conformations, and it will speed up the docking procedure. Therefore, it is possible to select complementary ligands or complementary conformations of a ligand and the macromolecules, by comparing their fingerprints previously stored in a database.
Automatic structure determination of organic molecules: Principle and implementation of the LSD program
Authors: Nuzillard Jean‐Marc 
Published: September 2010

AbstractThe LSD (Logic for Structure Determination) program generates organic molecular structures from 1D and 2D NMR data without resorting to chemical shift databases. Its use in the resolution of natural product structure determination problems has been already reported in the literature. This paper describes how data and structures are internally represented and processed by LSD to build solution structures.
Isophorone‐based fluorescent dopant for red organic electroluminescence device
Authors: Liu Di , Zhen Chang‐Gua , Hou Yuan‐Jun , Wang Xue‐Song , Zou De‐Chun , Zhang Bao‐Wen , Cao Yi 
Published: September 2010

AbstractIsophorone‐based red fluorescent compound 3‐(dicyanomethylene)‐5,5‐dimethyl‐1‐[2‐(N‐ethyl‐3‐carbazyl) ethylene]cyclohexene (DCDCC) was synthesized for use in organic light‐emitting diodes (OLEDs). DCDCC was characterized by narrow emission in photoluminescence with full‐width at half‐maximum of only 50 nm in solution and in thin solid film of 70 nm width. Electroluminescence devices with configuration of ITO/NPB/Alq3:DCDCC/Alq3/Mg: Ag were fabricated utilizing DCDCC as dopant emitter. An efficient red emission peaked at 612 nm was obtained for the device with 1% (wt.%) DCDCC in Alq3. The maximum luminance and current efficiency were as high as 3700 cd/m2 at 14 V and 1.25 cd/A at 150 mA/cm2, respectively.
Hydrolysis of cephanone in SDS/n‐C5H11OH/H2O system
Authors: Qian Jun‐Hong , Guo Rong 
Published: September 2010

AbstractThe hydrolysis of cephanone in SDS micelle and SDS/n‐C5H11OH/H2O O/W microemulsion was studied through Uv‐vis absorption spectroscopy. The change of pH value in the hydrolysis of cephanone was determined. The result shows that pH value decreases in the process of the hydrolysis, and that the SDS micelle and SDS/n‐C5H11OH/H2O O/W microemulsion accelerate the hydrolysis of cephanone compared with water.
Phase behavior and dielectric spectroscopy of the sodium dodecyl trioxyethylene sulfate/n‐butanol/water system
Authors: Wei Su‐Xiang , Mu Jian‐Hai , Zhao Kong‐Shuang , Lei Jian‐Ping , Li Gan‐Zuo 
Published: September 2010

AbstractThe phase diagram of the ternary system of sodium dodecyl trioxyethylene sulfate (SDES)/n‐butanol/water is obtained at (30.0 ± 0.1) °C. There exists a clear, isotropic, and low‐viscosity L phase, which could be divided into W/O micelle, bi‐continuous (B. C.) phase and O/W micelle by conductivity measurements. Dielectric Relaxation Spectroscopy (DRS) measurements are applied to investigate microstructure changes of this system. For samples with a fixed weight ratio, SDES/n‐butanol = 3/7, DRS indicates a structure transition from W/O to O/W micelles via B.C. phase with the increase of water content. For the samples with a fixed weight ratio, SDES/H2O = 4/6, DRS can presents that there exist changes of onefold structure size of W/O micelles as n‐butanol content increases. The results obtained from DRS and their analyses are in good agreement with those from phase diagram and conductivity measurements.
Study on pair correlation energies of isoelectronic systems F−, HF and H2F+
Authors: Zhuo Shu‐Ping , Wei Ji‐Chong , Ju Guan‐Zhi 
Published: September 2010

AbstractThe intrapair and interpair correlation energies of F−, HF and H2F+ systems are calculated and analyzed using MP2‐OPT2 method of MELD program with cc‐PVSZ* basis set. From the analysis of pair correlation energies of these isoelectronic systems, it is found that the 1sF2 pair correlation energy is transferable in these three Isoelectronic systems. According to the definition of pair correlation contribution of one electron pair to a system, the pair correlation contribution values of these three systems are calculated. The correlation contribution values of inner electron pairs and H–‐F bonding electron pair in HF molecule with those in H2F+ system are compared. The results indicate that the bonding effect of a molecule is one of the important factors to influence electron correlation energy of the system. The comparison of correlation energy contributions including triple and quadruple excitations with those only including singles and doubles calculated with 6–311 ++ G(d) basis set shows that the higher‐excitation correlation energy contribution gives more than 2% of the total correlation energy for these systems.
Synthesis, crystal structure of ruthenium 1,2‐naphthoquinone‐1‐oxime complex and its mediated CC coupling reactions of terminal alkynes
Authors: Sun Ke , Wong Wing‐Tak , Liu Xiao‐Xia , Zhang Bao‐Yan 
Published: September 2010

AbstractSubstituted decarbonylation reaction of ruthenium 1,2‐naphthoquinone‐1‐oxime (1‐nqo) complex, cis‐, cis‐[Ru| ζ2‐N(O)C10‐H6O|2(CO)2] (1), with acetonitrile gave cis‐, cis‐[Ru | ζ2‐ N(O)C10H6O|2(CO)(NCMe)] (2). Complex 2 was fully characterized by 1H NMR, FAB MS, IR spectra and single crystal X‐ray analysis. Complex 2 maintains the coordination structure of 1 with the two naphthoquinonic oxygen atoms, as well as the two oximato nitrogen atoms located cis to each other, showing that there is no ligand rearrangement of the 1‐nqo ligands during the substitution reaction. The carbonyl group originally trans to the naphthoquinonic oxygen in one 1‐nqo ligand is left in its original position [O(5)‐Ru‐C(1), 174.0(6)°], while the other one originally trans to the oximato group of the other 1‐nqo ligand is substituted by NCMe [N(1)‐Ru‐N(3), 170.6(6)°]. This shows that the carbonyl trans to oximato group is more labile than the one trans to naphthoquinonic O atom towards substitution. This is probably due to the comparatively stronger ± back bonding from ruthenium metal to the carbonyl group trans to naphthoquinonic O atom, than the one trans to oximato group, resulting in the comparatively weaker Ru–‐CO bond for the latter and consequently easier replacement of this carbonyl. Selected coupling of phenylacetylene mediated by 2 gave a single trans‐dimerization product 3, while 2 mediated coupling reaction of methyl propiolate produced three products: one trans‐dimerization product 4 and two cyclotrimeric products 5 and 6.
Study of tea digitized chromatographic fingerprint spectra using micellar electrokinetic chromatography
Authors: Song Guan‐Qun , Lin Jin‐Ming , Qu Feng , Dong Wen‐Ju 
Published: September 2010

AbstractThis paper described the principle of digitized chromatographic fingerprint spectrum and established digitized chromatographic fingerprint spectra of ten brands of Chinese famous tea by the micellar electrokinetic chromatography. This work was done using a 25 mmol ± L−1 sodium dodecylsulfate in a 20 mmol ± L−1 borate (pH 7.0) solution as running buffer, 20 kV applied potential and detection at 280 nm. The chromatographic fingerprint spectra were digitized by the relative retention value (a) and the relative area (Sr), and were analyzed to identify the tea samples. In the absence of the standard samples, the present method was easy setup and inexpensive, and provided the applicable information for the quality assessment of teas.
Investigation of quantitative relationship between adsorbed amount of solute and solvent concentration at relatively high solute concentration by frontal analysis in RPLC
Authors: Wang Yan , Geng Xin‐Du , Zebolsky Don M. 
Published: September 2010

AbstractIn previous paper a new adsorption isotherm which relates the amount of solute absorbed to the solvent concentration is proposed and simplified, and it only can be used at lower solute concentration. In this article the scope of the new adsorption isotherm is extended and the expressions with three and four parameters are obtained. The equations with multi‐parameters are valid when the adsorbed amounts are larger and show nonlinear logarithmic relationships. Tests with a homologue of aromatic alcohols by frontal analysis in reversed phase liquid chromatography demonstrate that the experimental results fit those equations well. In addition, the predicted values by the multiparameters were found to fit the experimental values well also. The parameters have physical meaning only for the two‐parameter equation for the aromatic alcohols.
Amplified DNA detection sensitivity using streptavidin‐biotinylated protein complex: characterization by electrochemical impedance spectroscopy
Authors: Cheng Zhi‐Liang , Yang Fan , Huang Hai‐Zhen , Yang Xiu‐Rong 
Published: September 2010

AbstractThiol‐terminated oligonucleotide was immobilized to gold surface by self‐assembly method. A novel amplification strategy was introduced for improving the sensitivity of DNA hybridization using biotin labeled protein‐streptavidin network complex. This complex can be formed in a cross‐linking network of molecules so that the amplification of the response signal will be realized due to the big molecular size of the complex. It could be proved from the impedance technique that this amplification strategy caused dramatic improvement of the detection sensitivity. These results give significant advances in the generality and sensitivity as it is applied to biosensing.
Reaction of imidazole anions with difluorodiiodomethane and their products conversion in sulfinatodehalogenation system
Authors: Xiao Ji‐Chang , Chen Qing‐Yun 
Published: September 2010

AbstractTreatment of difluorodiiodomethane with TV‐sodium salts of imidazoles at ‐ 15 °C gave N‐difluoroiodomethylated imidazoles (3) in good yields. The addition of 3 to alkyne or alkenes initiated by sodium dithionate at room temperature resulted in the corresponding adducts in high yields.
Enzymatic enantioselective synthesis of (R)‐2‐trimethylsilyl‐2‐hydroxyl‐propionitrile by defatted apple seed meal
Authors: Li Ning , Zong Min‐Hua , Wang Ju‐Fang , Liu Chen , Wu Hong 
Published: September 2010

AbstractThe enantioselective synthesis of (R)‐2‐trimethylsilyl‐2‐hydroxyl‐propionitrile by (R)‐oxynitrilase contained in defatted apple seed meal in a biphasic system was successfully performed. The influences of some factors on the reaction were investigated systematically. Diisopropyl ether was found to be the best for this reaction among all the organic solvents examined. The optimal concentration of defatted apple seed meal, aqueous phase content, concentrations of acetyltrimethylsilane and acetone cyanohydrin, buffer pH, reaction temperature were 4% (W/V), 23% (V/V), 20 mmol ± L−1, 40 mmol ± L−1, pH = 5.0 and 40 °C, respectively, under which the initial reaction rate, substrate conversion and product enantiomeric excess were 9.4 mmol ± L−1 ± h−1, 99% and >99%, respectively.
Asymmetric pinacol coupling of aromatic aldehydes catalyzed by TiCl4(THF)2‐Zn/chiral diamines
Authors: Li You‐Gui , Jiang Chang‐Sheng , Tian Qing‐Shan , Ke Yu‐Ping , You Tian‐Pa 
Published: September 2010

AbstractAsymmetric pinacol coupling of aromatic aldehydes catalyzed by chiral diamines/low‐valent titanium complexes gave corresponding pinacols in good yields with high diastereoselectivity and moderate enantioselectivities.