bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen Atom Adsorption and Diffusion on Pd Low‐index Surfaces and (311) Stepped Surface
Authors: Wang Ze‐Xin , Jia Xiang‐Feng , Tian Feng‐Hui , Chen Shou‐Gang 
Published: September 2010

AbstractThe 5‐parameter Morse potential (5‐MP for short) of the interaction system between an oxygen atom and palladium surface clusters was constructed. The adsorption and diffusion of an oxygen atom on low index surfaces Pd (100). Pd (111). Pd (110) and Pd (311) stepped surface were investigated in detail with 5‐MP. It is found that fcc and hcp sites on the (111) surface and (111) microfacets are equivalent. The calculation results show that O atom adsorbs in the three‐fold hollow site, and the long‐bridge site is a stable site both in regular Pd (110) surface and in the (1×2) missing‐row reconstruction structure. Moreover, in the study of O‐Pd (311) surface system, We conclude that there are two stable adsorption states (four‐fold site: H4, three‐fold site: Hn) on O‐Pd (311) surface and the three‐fold site (Hf) is the metastable adsorption. At low coverage oxygen atom favors the four‐fold hollow site (H4).
Baker's Yeast Mediated Reduction of Optically Active Diketone
Authors: Zheng Guo‐Jun , Gao Xiao‐Lei , Chen Jin‐Chun , Li Yu‐Lin 
Published: September 2010

AbstractBaker's yeast mediated reduction of optically active diketone is described. The two keto pups are efficiently differentiated and the ee value of the recovered material is considerably raised. It affords highly optically active key intermediates efficiently for the synthesis of natural polyhydroxylated agarofuran products.
Solid Phase Synthesis of 2‐Substituted1, 3‐Oxazin‐6‐ones Using Resin‐bound Cyclic Malonic Acid Ester
Authors: Liu Zhan‐Xiang , Ruan Xiu‐Xiu , Huang Xian 
Published: September 2010

AbstractA facile solid phase. synthesis of 2‐substituted1,3‐oxazin‐6‐ones using polymer‐supported Meldrum's acid has been reported. Reaction of the resin‐bound cyclic malonic acid ester with triethyl orthoformate and subsequent double substitution with amide, afforded the corresponding polymer‐supported acylaminomethylene cyclic malonic acid ester, which upon thermal treatment led to1, 3‐oxazin‐6‐ones in good yields and with high purity.
A Facile One‐pot Synthesis of2,5‐Disubstituted Oxazoles Using Poly[styrene(iodosodiacetate)]
Authors: Huang Xian , Chen Jiang‐Min 
Published: September 2010

Abstract2.5‐Disubstituted oxazoles were prepared conveniently by treatment of aromatic α‐methyl ketones and nitriles with poly[styrene(iodosodiacetate)] in a one‐pot manner.
Transport Properties of Fluids in Micropores by Molecular Dynamics Simulation
Authors: Liu Ying‐Chun , Wang Qi , Lü Ling‐Hong 
Published: September 2010

AbstractThe transport properties of fluid argon in rnicropores. i.e. diffusivity and viscosity. were studied by molecular dynamics simulations. The effects of pore width, temperature and density on diffusivity and viscosity were analyzed in micropores with pore widths from 0.8 to 4.0 run. The results show that the diffusivity in micropores is much lower than the bulk diffusivity, and it decreases as the pore width decreases; but the viscosity in micropores is significantly larger than the bulk one, and it increases sharply in narrow micropores. The diffusivity in channel parallel direction is obviously larger than that in channel perpendicular direction. The temperature and density are important factors that obviously affect diffusivity and viscosity in micropores.
Theoretical Studies on the Third‐order Nonlinear Optical Properties and Two‐photon Absorption of Stilbene Derivatives
Authors: Ai‐Min Ren. , Feng Ji‐Kange , Liu Xiao‐Juan 
Published: September 2010

AbstractDifferent types of stilbene derivatives (D‐‐D, A‐‐A, D‐‐A) were investigated with AM1, and specially, equilibrium geometries of symmetrical stilbene derivatives (D‐‐D) were studied using of PM3. With the same method INDO/CI, the UV‐vis spectra were explored and the position and strength of the two‐photon absorption were predicated by Sum‐Over‐States expression. The relationships of the structures, spectra and nonlinear optical properties have been examined. The influence of various substituents on two photon absorption cross‐sections was discussed micromechanically.
Kinetic Studies on Na+/K+‐ATPase by Using Thermokinetic Method
Authors: Li Xia , Li Jie , Wang Zhi‐Yong , Xie Xiu‐Yin , Yang Xi , Wang Cun‐Xin 
Published: September 2010

AbstractNa+/K−‐ATPasc (EC 3.6.1.3) is an important membrane‐bound enzyme. By using microcalorimetry, the thermokinetic method was developed to kinetic studies on Na+/K+‐ATPase for the first time. Compared with other ones, the method provided accurate measurements of not only thermodynamic data but also the kinetic data. At 310.15 K and pH=7.4, the molar reaction enthalpy ΔrHm, was measured as (‐40.408k 1.9) kJ mol−1. The Michaelis constant Km was determined to be (0.479 0.020) 10−‐3 mol L−1 and consistent with literature figure which is about 0.5 10−‐3 moi L−1. The maximum velocity Vmax obtained was (0.6810.026) μmol Pi min−1 mg protein−1. All of the data have good repeatability and self‐consistency. The reliability of thermokinetic method was verified by the experimental results and further confirmed by colorimetric studies. Moreover. the effect of enzyme pre‐dilution on its activities was also investigated.
Hydrothermal Synthesis and Crystal Structure of [Mn(phen)‐(m‐phth)]n (phen=1, 10‐phenanthroline, m‐phth=isophthalate)
Authors: Bi Wen‐Hua , Sun Dao‐Feng , Cao Rang , Li Xing , Shi Qian 
Published: September 2010

AbstractHydrothermal reaction of1,2,4‐benzenetricarboxylic acid, and MnCl24H2O with1,10‐phenanthroline gave the title complex, [Mn(phen)(m‐phth)]n, which crystallizes in the monoclinic system, space group P2/c with a= 0.83582(3) nm, b=1.04246(4) nm, c=1.87777(7) nm, β= 100.314(2), V=1.60%8(10) nm3, Z=4, and the final R =0.0576, wR =0.1294. In the complex, each Mn(II) ion is coordinated to four O atoms of carboxylate groups and two N atoms of phen. Isophthalate was generated in situ through the loss of one carboxylate group of1,2,4‐benzenetricarboxylic acid under the hydrothermal condition. Each isophthalate is bound to three manganese atoms through O atom of carboxylate in bridging and chelating fashion, affording manganese(II) pairs that are linked by the isophthalate group to yield a zig‐zag chain along the c‐axis.
Flow‐Injection Electrochemiluminescence Detecting Rifampicin Based on Its Sensitizing Effect
Authors: Ma‐Yan Hong , Zheng Xing‐Wang , Zhang Zhu‐Jun 
Published: September 2010

AbstractA new flow‐injection electrogenerated chemieluminescence (ECL) method for the determination of rifampicin was developed. The method is based on the sensitizing effect of rifampicin on the weak ECL signal of electrochemical oxidation of luminol on the surface of the platinum flake electrode in the medium of 0.02 mol L−1 Na2B4O7. This ECL response is in the range of 1.0 10–4.0 10−‐1 mol L−1 rifampicin with a detection limit of 8.0 10−‐9 mol L−1. The relative standard deviation is 1.8%. This method has been applied successfully to the determination of rifampicin in capsule. ocustilla and urine samples.
Design, Synthesis and Pregnancy‐Terminating Activity of 2‐Aryl Imidazo[2, 1 ‐a]isoquinolines
Authors: Shang Zhi‐Cai , Hu Gui‐Xiang , Wu Tian‐Xing , Fang Yui‐Ying , Yu Qing‐Sen 
Published: September 2010

AbstractIn order to clarify the structural requirement of pregnancy‐terminating drugs, the quantitative structure‐activity relationship (QSAR) of 2‐aryl imidazo[2, 1‐a]isoquinolines was studied on the basis of quantum mechanical calculation and multiple regression analysis. A Good correlation equation was obtained (r2=0.925, q2=0.871). Some new compounds were designed according to the equation. Two of them, compounds 21 and 22, were synthesized and evaluated in NIH mice. The results showed that the difference of activity between 21 (median effective dose ED%=0.943 mg/kg/day) and 22 (ED50= 1.099 mg/kg/day) was small and both of them were potent. It is also agreed with the computational results. Compared with L14105 which is the most potent pregnancy‐terminating agent, these two compounds possess high activity. The evaluation of the anti‐implanting activity showed that they were 100% effective at tested dosage 50.0, 25.0, 12.5 mg/kg/day 3 days in oral administration, which proved the both of them had anti‐implanting activity and low first‐pass effects.
Microencapsulation of n‐Eicosane as Energy Storage Material
Authors: Lan Xiao‐Zheng , Tan Zhi‐Cheng , Zou Guang‐Long , Sun Li‐Xian , Zhang Tao 
Published: September 2010

AbstractFor heat energy storage application, polyurea microcapsules containing phase change material, n‐eicosane, were synthesized by using interfacial polymerization method with toluene‐2,4‐diisocyanate (TDI) and diethylenetriamine (DETA) as monomers in an emulsion system. Poly(ethylene glycol)octyl‐phenyl ether (OP), a nonionic surfactant, was the emulsifier for the system. The experimental result indicates that TDI was reacted with DETA in a mass ratio of 3 to 1. FT‐IR spectra confirm the formation of wall material, polyurea, from the two monomers, TDI and DETA. Encapsulation efficiency of n‐eicosane is about 75%. Microcapsule of n‐eicosane melts at a temperature close to that of n‐eicosane, while its stored heat energy varies with core material n‐eicosane when wall material fixed. Thermo‐gravimetric analysis shows that core material n‐eicosane, micro‐n‐eicosane and wall material polyurea can withstand temperatures up to 130, 170 and 250 °C, respectively.
SnCl2/Cu‐mediated carbonyl allylation reaction in water: Scope, selectivity and mechanism
Authors: Tan Xiang‐Hui , Hou Yong‐Quan , Liu Lei , Guo Qing‐Xiang 
Published: September 2010

AbstractCopper was found to be able to promote the SnCl2‐mediated carbonyl allylation reactions in water, giving the corresponding homoallylic alcohol products in very high yields. Detailed studies showed that the reaction could be applied to a variety of carbonyl compounds including those with hydroxyl, amino and nitro groups. It was also found that this reaction showed good regioselectivities for some substrates. Furthermore, carefully controled experiments and in situ NMR measurements provided important insights into the mechanism of the newly developed reaction.
Ramberg‐Bäcklund Rearrangement Approaches to the Synthesis of Natural Bibenzyls
Authors: Wang Xiao‐Long , Liu Dong , Xia Ya‐Mu , Cao Xiao‐Ping , Pan Xin‐Fu 
Published: September 2010

AbstractThe Ramberg‐Bäcklund rearrangement has been successfully utilized to convert readily available α‐ and α'‐hydrogen bearing substituted dibenzyl sulfones into corresponding stilbene derivatives, which is conveniently followed by hydrogenation in the presence of 10% Pd/C to afford the natural bibenzyls.
Synthesis of (ρ‐formylphenyl)azo calix[4]arenes
Authors: Bal Zhu , Yu Lei , Lu Guo‐Yuan , Guo Xun 
Published: September 2010

AbstractFive novel azo calix[4]arenes were reported. The p‐aminobenzaldehyde was diazotized with sodium nitrite in aqueous hydrochloride solution. Mono‐, bis‐, his‐ and tetrakis(p‐formylphenyl)azo calix[4]arenes (including proximal and distal isomers) were obtained respectively by diazo‐coupling in different molar ratio to calix[4]arene (1) under pH=7.5‐8.5 at 0‐5 C. All (p‐formylphenyl)azo calix[4]arenes were characterized by 'H NMR, 13C NMR, IR, MS (ESIMS) spectroscopies and elemental analysis.
A two‐dimensional lanthanide coordination framework with a new amide‐type tripodal ligand,2,2′,2″‐nitrilotris{[(2′‐benzylaminoformyl)phenoxy]ethyl}amine
Authors: Fan Jun , Zhang Wei‐Guang , Tan Min‐Yu , Tang Yu , Liu Wei‐Sheng , Tang Ning , Yu Kai‐Bei 
Published: September 2010

AbstractThe La(III) complex with a new amide‐type tripodal ligand,2,2′.2″‐nitrilotris{[(2′‐benzylaminofomyl)‐phenoxylethyl)amine (L), was synthesized and characterized by X‐ray crystallographic analysis. Crystal data: C48H55.50LaN7O18.75, Mr=1169.40, monoclinic. space group, P21/n, a= 1.0644(3) nm. b=2.3889(5) nm, c= 2.1917(5) nm, β=90.65°, V=5.573(2) nm3, Z=1, Dc=1.394 g°cm−3, R1=0.0487, wR [1>2s̀(I)]=0.1266. The results reveal that each La(III) ion binds to 9 oxygen atoms, three of which belong to carbonyl groups from three tripodal ligands and six to three bidentate nitrate groups and a two‐dimensional sheet of 4.82 networks is assembled by metal‐ligand coordination interaction. L, a heptadentate compound, merely acts as a tridentate bridging spacer due to its steric hindrance and links the La(III) ions as three‐connected nodes.
Microcalorimetric investigation on the kinetics of the oxidation of ascorbic acid with hydrogen peroxide
Authors: Meng Xiang‐Guang , Kou Xing‐Ming , Xie Jia‐Qing , Du Juan , Zeng Xian‐Cheng 
Published: September 2010

AbstractBased on the thermokinetic theory, a novel thermokinetic research method‐self‐function regression method, which could be used to determine the kinetic parameters kl. k2 and k‐1 of the complex reaction: B + \documentclass{article}\usepackage{chemarr}\pagestyle{empty}\begin{document}${\rm C} \xrightleftharpoons[{k_{- 1}}]{{{\rm k}_{\rm 1}}} {\rm I} \xrightarrow[]{{\rm k}_{\rm 2}} {\rm P},$\end{document}, was proposed in this paper. The kinetics of the reaction of ascorbic acid (H2A) with hydrogen peroxide was investigated at pH=5‐7 and T=298.15 K, and the kinetic parameters k1 k2 and k‐1 were obtained with this method. The kinetics of the reaction was investigated in detail. The kinetic parameters of the oxidation of ascorbic monoanion (HA−) and ascorbic dianion (A2‐) with hydrogen peroxide were 3.33×10−3 s−1 and 25.48 s−1 at 298.15 K, respectively. The molar enthalpy change for the reaction was ‐554.64 kJ · mol−1 in phosphate buffer solution at pH 7 and at 298. 15 K.
Effects of temperature raising speed on the growth of BN crystals in hydrothermal solutions
Authors: Yu Mei‐Yan , Li Kai , Cui De‐Liang , Dong Shou‐Yi , Wang Qi‐Long , Jiang Min‐Hua 
Published: September 2010

AbstractCubic boron nitride (cBN) and orthorhombic boron nitride (oBN) crystals have been prepared in hydrothermal solutions by reacting H3BO3+NaN3+P and H3BO3+NaN3+N2H4 respectively. The experimental results indicated that, if the temperature was increased rapidly, both the yield and perfectness of BN crystals became poor. On the contrast, the yield and perfecmess of BN crystals can be improved very much by slowly increasing the temperature of the reaction mixture. The results of X‐ray powder diffraction (XRD), Fourier transform infrared spectrum (FTIR) and high resolution transmission electron microscopy (HRTEM) proved that the samples were composed of oBN and cBN.
A,C‐bridged calix[6]arene: Relationship between the length of bridge and conformation
Authors: Gong Shu‐Ling , Chen Yi‐Kun , Li Jun , Duan He‐Ping , Chen Yuan‐Yin 
Published: September 2010

AbstractThree new A,C‐diamide bridged p‐tert‐butylcalix[6]arenes were synthesized from p‐tert‐butylcalix[6]arenes by bridging ClCH2CONH(CH2)nNHCOCH2Cl (n=3, 4, 6) in acetonitrile using K2CO3 as a base in 17%‐25% yields. It was found that the bridged calix[6]arenes with shorter bridges (n=2, 3, 4 in N', N'‐bischloroacetodiamines) adopt cone conformation, but the last one (n=6) adopts alternate conformation, i.e., accompanying the lengthening of bridge, the conformation of A,C‐bridged calix[6]arenes changes from cone to alternate.
Immobilization of HX: [Hmim]X as halogenating agent, recyclable catalyst and medium for conversion of alcohols to alkyl halides
Authors: Wu Hai‐Hong , Sun Jing , Yang Fan , Tang Jie , He Ming‐Yuan 
Published: September 2010

AbstractHX is immobilized by reaction of halogen acid with methylimidazole, and the formed ionic liquid [Hmim]X was used as halogenating agent, catalyst as well as medium for conversion of alcohols to alkyl halides. Excellent yields were obtained. The halides produced could be easily separated from the reaction mixture via simple decantation, and the ionic liquid [Hmim]X could be regenerated conveniently by adding equivalent of halogen acids followed by removal of water.
Dialdehyde in heterocyclic synthesis: Synthesis of compounds containing two 4H‐benzopyran building blocks under microwave irradiation
Authors: Feng You‐Jiana , Miao Chun‐Bao , Gao Yuan , Tu Shu‐Jiang , Fang Fang , Shi Da‐Qing 
Published: September 2010

AbstractThe syntheses of 4H‐benzopyran derivatives were investigated using dialdehyde as a key starting material. The reaction proceeds under microwave irradiation in good yield (87%‐95%) with short reaction time (5‐8 min), therefore providing a rapid and efficient method of synthesizing a variety of compounds containing two 4H‐benzopyran units.
Studies on natural CXN zeolite: Modification, framework De‐alumination and ion‐exchange
Authors: Long Ying‐Cai , Xia Xiao‐Hui , Yang Bo , Zhang Ling‐Mei , Zhou Wei‐Zheng , Cao Zhi‐Long , Li Cai‐Yun 
Published: September 2010

AbstractA natural CXN zeolite (stilbite, type code‐STI) discovered in China was modified with NH: exchange by using ammonium salt and calcinations (procedure I), or with NH: exchange followed by treatment with acid (procedure rr). The coordination state of Si and Al atoms in the framework. the property of ion exchange, and the adsorption of the H‐STI zeolite samples prepared by different modification procedure were investigated with XRD, EDX, 29Si and 27Al MAS NMR, Ag+ ion exchange and N2 adsorption. The results of the investigations indicate that different procedure of the modification made variety on the distribution of the framework Si atoms and A1 atoms, the content of non‐framework aluminum. and the blocking channels and the shielding effect to the positions of the exchangeable cations. The H‐STI zeolite prepared by the procedure II possesses high ion exchange capacity, open and perfect pore system, and hgh thermal stability.
Synthesis, structure and biological activities of novel triazole compounds containing N,N‐dialkyldithiocarbamate moiety
Authors: Xu Liang‐Zhong , Jian Fang‐Fang , Shi Jian‐Gang , Sun Ping‐Ping , Jiao Kui 
Published: September 2010

AbstractThe two compounds, 2, 2‐dimethy1‐4‐S‐(N,N‐ dimethyldithiocarbamato)‐5‐(1, 2, 4‐triazol‐1‐yl)‐propione (1) and 2, 2‐dimethyl‐4‐S‐(N,N,‐diethyldithiocarbamato)‐5‐(1, 2, 4‐triazol‐1‐yl)‐3‐propione (2), were prepared by reacting N,N‐dialkyldithiocarbamate sodium with 2, 2‐dimethyl‐4‐bromo‐5‐(1, 2, 4‐triazol‐l‐yl)‐propione. Their structures were identified by elemental analysis, IR and 1H NMR spectroscopy. The structure of 1 has been determined by X‐ray single crystal structure analysis. It crystallizes in monoclinic system with space group P21/c, a=1. 2315(3) nm, b=1.2057(2) nm, c =1.2532(3) nm, β=118.55(3)°, 2=4, V=1.6345(6) nm3, Dc=1.221 g/cm3, p=0.324 mm −1, F(000)=640. final R1 =0.0449. There is obvious potentially weak C‐H···N intermolecular interaction in the crystal, which stabilizes the crystal structure. The result of the biological test showed that the two compounds have fungistasis and plant growth regulating activities.
Different biotinylation strategies for competitive immunoassay of estradiol
Authors: Zhao Jin‐Fu , Wang Yong‐Cheng , Li Yuan‐Zong , Chang Wen‐Bao 
Published: September 2010

AbstractStudy on biotinylation strategies for competitive immunoassay of estradiol (Ez) was carried out. Two types of competitive enzyme immunoassay (WIA) with Biotin‐Avidin amplification system were established and optimized. The E2‐Biotin conjugate was used as a mere in one assay, and biotinylated antibody was used as a tracer in the other. In both of EIAs, horseradish peroxidase‐labelled Avidin (Avidin‐HRP) was used with a spectrometric determination of enzyme activity. The precision, sensitivity and specificity were measured and compared. The results showed that although both were satisfactory in specificity, the EL4 with hapten‐Biotin showed to be superior to the EL4 with biotinylated antibody in sensitivity and precision. The limit of detection of serum E2 was 8 and 50 pg/mL with E2‐Biotin and biotinylated antibody as tracer, respectively.
Study on the reaction of proteins with 5′‐nitrosalicylfluorone‐molybdenum(VI) complex by spectrophotometry in PVA 124 microemulsion
Authors: Wei Qin , Wu Dan , Du Bin , Zhang Hui , Ou Qing‐Yu 
Published: September 2010

AbstractThe application of 5′‐nitrosalicylfluorone (5′‐NSF)‐molybdenum(VI) complex as a spectroscopic probe was studied. In the buffer medium of HOAc‐NaOAc at 3.45 and in the presence of PVA 124 microemulsion, 5 '‐NSF‐Mo(VI) complex combines protein rapidly to form a stable compound. leading to an absorbance decrease at 525 nrn of 5′‐NSF‐Mo(VI) complex. According to this change, microdetermination of protein has been described. Bovine serum albumin (BSA) could be determined in the linear range of 0–16 pg*mL with the detection limit of 11 ng*mL−1. Many amino acid and metal ions studied do not interfere with the assay. The method possesses high sensitivity as well as high selectivity. It can be used to determine protein in human urine and milk powder successfully. The relative standard deviations are in all instances less than 4.7%. and the recoveries are between 97.6% and 106.0%. Moreover, the binding number of BSA with the complex, which is determined by using molar ratio, Rosenthal graphic and slope ratio methods, is in good agreement with each other.
Synthesis, characterization and the effect of glucose‐lowering of guanidino acid oxovanadium(IV) complexes
Authors: Liu Ju‐Tao , Wang Xiao‐Hong , Li Jian‐Xin , Liu Jing‐Fu 
Published: September 2010

AbstractTwo guanidino acid oxovanadium(IV) complexes have been synthesized. Preliminary tests in vivo have shown that the two title complexes all display lowering glucose activity in vivo to STZ‐rats. The effect of glucose‐lowering of guanidino acetic acid oxovanadium(IV) complex in vivo is higher than that of guanidino propanoic acid oxovanadium(IV) complex.
Syntheses and crystal structures of benzyltin(IV) derivatives of 2‐mercaptobenzothiazole
Authors: Zhang Ru‐Fen , Qiu Lin‐Lin , Li Feng , Ma Chun‐Lin 
Published: September 2010

AbstractThe complexes (PhCH2Sn(MBT)2 (2) and (PhCH2Sn(MBT) (3) (HMBT: 2‐mercaptobenzothiazole) have been synthesized and characterized by elemental analyses, and IR, 1H, 13C, 119Sn NMR spectrometries and X‐ray diffraction. Studies on the crystal structures of 2 and 3 show that HMBT acts as bidentate ligand through chelation of N and S atoms. Complex 2 contains a six‐coordinate tin atom with the axial angle C(15)‐Sn(1)‐C(22) 129.6(2)o. And the tin environment of complex 3 is a distorted cis‐trigonal bipyramid with C(8)‐Sn(1)‐N(1) 158.80o.
Quantum chemical study on reaction of acetaldehyde with hydroxyl radical
Authors: Li Ming , Zhang Jin‐Sheng , Shen Wei , Meng Qing‐Xi 
Published: September 2010

AbstractThe reaction of acetaldehyde with hydroxyl radical was studied by means of quantum chemical methods. The geometries for all the stationary points on the potential energy surfaces were optimized fully, respectively, at the G3MP2, G3. and MP2/6‐311++G(d,p) levels. Single‐point energies of all the species were calculated at the QCISD/6‐311++G(d,p) level. The mechanism of the reaction studied was confirmed. The predicted product is acetyl radical that is in agreement with the experiment.