bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison between hydrogen‐transfer and fluoro‐transfer reactions on the microcanonical unimolecular rate constants
Authors: Feng Wen‐Lin , Zhang Shao‐Wen , Wang Yan , Wu Jun‐Nan , Li Zong‐He 
Published: September 2010

AbstractThe microcanonical rate constants for the hydrogen‐transfer process of HCCF (reaction 7) and the fluoro‐transfer process of FCCF (reaction 8) are carried out with tunneling correction and curvature correction. The results show that the tunneling effects and curvature effects on the rate constant of reaction 7 is quite different from that of reaction 8. The rate constants for different rotational states are also studied for these reactions.
Staircase pulse voltammetry
Authors: Mo Jin‐Yuan , Chen Shao‐Hua , Zou Youg‐De , Cai Pei‐Xiang 
Published: September 2010

AbstractThe faradaic current of interest can often be obscured by some extraneous current. A new method called staircase pulse voltammetry (SPV), with which involving a potential pulse is superimposed on a staircase, is used for removing the double‐layer charging current This paper presents the theoretical consideration and the experimental evidence of this method for a simple reversible system and a catalytic process. The parameters affecting currents are also discussed. Experimental verifications are in agreement with the theories.
Enhancement of intramolecular excimer formation and photodimerization of anthrylmethyl α,ω‐alkanedioates via hydrophobic interactions
Authors: Tung Chen‐Ho , Li Yi 
Published: September 2010

AbstractThe fluorescence spectra and photodimerization of anthrylmethyl α,ω‐alkanedioates (A‐Mn‐A; both in organic and in aqueous organic mixed solvents have been studied. In aqueous organic mixed solvents strong intramolecular excimer emission is detected and the quantum yield for the intramolecular photodimerization is significantly greater than those in organic solvents. These observations suggest that hydrophobic interactions force A‐Mn‐A molecule to self‐coil. The ratio of the head‐to‐head to head‐to‐tail products in the intramolecular photodimers of A‐Mn‐A depends on the length of the linking chain. This work presents a successful example of application of hydrophobic interactions to enhancement of large‐ring formation.
Structural study on a bioactive fructan from the root of Achyranthes bidentata Blume
Authors: Yu Biao , Tian Geng‐Yuan , Hui Yong‐Zheng 
Published: September 2010

AbstractThe structure of a saccharide component (Abs), with pronounced activity of improving immunity system, isolated from the root of Achyranthes bidentata Blume, a traditional Chinese herbal medicine, was studied. Based on 13C NMR, HPLC, and methylation analyses, Abs was shown to be a mixture of short‐chain fructans with an average dp of8, containing more (2→6) than (2→l) linked β‐D‐fructofuranosyl residues, with branching at O‐6 or O‐1 of 18% of the D‐fructofuranosyl residues.
Syntheses of fluoroalkyl derivatives of two biologically active oligopeptides
Authors: Li Rui‐Qing , Huang Wei‐Yuan 
Published: September 2010

AbstractFluoroalkyl derivatives of two biologically active oligopeptides (m‐CF3)Tyr1j‐Leu‐enkephalin. [(m‐C2F4Cl)Tyr1]‐Leu‐enkephalin and [(m‐COCF2Cl)Tyr2]‐melanocyte‐stimulating hormone releasing hormone have been synthesized. Studies on the activities of these peptides are underway.
Synthesis of dinucleoside, di(2′‐deoxy‐2′‐fluoro)nucleoside phosphates and phosphorothioates and their stability to snake venom phosphodiesterase
Authors: Zheng‐Fu Wang , Xiao‐Hui Gu , Yao‐Quan Chen 
Published: September 2010

AbstractDithymidine, di(2′‐deoxy‐2′‐fluoro)‐cytidine and ‐uridine phosphate and phosphorothioate have been synthesized. The stereochemistry of the condensation reaction between 2′‐deoxy‐2′‐fluoronucleoside phosphoramidite and nucleoside was preliminarily investigated. The diastereomer separation of the protected phosphorothioates was performed by silica gel column chromatography. The stability of these compounds to snake venom phosphodiesterase was determined.
A study on some macrocyclic bicopper(II) complexes as the model compounds of superoxide dismutase
Authors: Wen Qian , Guang‐Quan Mei , Qin‐Hui Luo 
Published: September 2010

Abstract24‐Membered macrocyclic bicopper(II) complexes wth bridging ligand imidzaolate, SCN−, N3− and H2O respectively were synthesized by condensation of diacetylpyridine with 3‐oxapentane‐1,5‐diamine. As the model compounds of superoxide dismutase (SOD), the relationship between their SOD activities and properties of bridging ligands and redox potentials of copper(II) were studied.
Determination of isoniazid and hydrazine by capillary electrophoresis with amperometric detection at a Pt‐particle modified carbon fiber microelectrode
Authors: Er‐Kang Wang , Wei‐Hong Zhou 
Published: September 2010

AbstractCapillary electrophoresis (CE)/electrochemical detection (EC) for the simultaneous determination of hydrazine and isoniazid has been developed. The electrochemical method uses a novel modified electrode dispersed with ultrafine platinum particles on the surface of a 30 μm carbon fiber microelectrode. The unique characteristic of the Pt‐particles modified carbon fiber microelectrode is its excellent stability. The current measurement for hydrazine is more sensitive than that of isoniazid. Selective determination of trace amount of free hydrazine in isoniazid and its formulation can be achieved at applied potential of 0.5 V.
Asymmetric total syntheses of (+)‐goniopypyrone and (+) ‐ 9‐ deoxygoniopypyrone
Authors: Zhi‐Cai Yang , Wei‐Shan Zhou 
Published: September 2010

AbstractAsymmetric total syntheses of (+)‐goniopypyrone (1) and (+)‐deoxygoniopypyrone (2) from methyl cinnamate (7) via (DHQ)2‐PHAL‐OsO4 catalyzed asymmetric dihydroxylation and highly stereoselective 2‐furylcopper addition in eight steps and eleven steps with overall yield of 20% and 13%, respectively, are described.
Supramolecular assemblies from single‐chain hydrocarbon fluorocarbon hybrid bolaamphiphiles
Authors: Biao Yu , Yong‐Zheng Hui 
Published: September 2010

AbstractThree types of single‐chain hydrocarbon fluorocarbon hybrid bolaamphiphiles were synthesized. They readily formed different kinds of organized supramolecular assemblies, including vesicles, tapes, and micellar fibers, in aqueous solution. The aggregates morphology was characterized by transmission electron microscopy (TEM) after negative staining. The superstructures of these aggregates seemed to be determined by the geometry and the head group's properties of the corresponding amphiphiles.
Thermodynamic parameters of interaction of HCl with alcohols in water III. HCl‐ethanol‐water system at 278.15–318.15 K
Authors: Ke‐Lei Zhuo , Jian‐Ji Wang , Wen‐Bin Liu , Jin‐Suo Lu 
Published: September 2010

AbstractThe emfs of cells without‐junction Pt, H2(g, p0)|HCl(mE)|AgCl‐Ag
Studies of a new series of ion‐pair complexes [Mo(dtc)4][Ln(dtc)4] (Ln = La‐Er, exp. Pm)
Authors: Qing‐Hong Fu , Guang‐Ren Zhang , Chun‐Ting Sun , Shu‐Yun Niu , Li‐Xin Wu 
Published: September 2010

AbstractA new series of ion‐pair complexes [Mo(dtc)4] [Ln(dtc)4] (LnLa‐Er, exp. Pm) were synthesized from MoCl5, LnCl3 and Nadtc in anhydrous methanol. The crystal structures of the four complexes, [Mo(dtc)4J[Ln(dtc)4] (LnNd, Sm, Ho and Er) have been determined by X‐ray diffraction. Spectroscopic properties of all these complexes are also discussed here.
Effect of Sb on the properties of anodic Pb(II) oxide film formed in alkaline solution
Authors: Qun‐Zhou Wang , Gang Liu , Hou‐Tian Liu , Wei‐Fang Zhou 
Published: September 2010

AbstractThe composition and properties of the anodic films formed on Pb and Pb‐3at. %Sb alloy at ‐0.10 V (vs. Hg/HgO) for 2.5 h in 0.1 mol·dm−3 NaOH solution (25°C) were investigated by cyclic voltammetry, linear sweep voltammetry, open circuit decay curve, photocurrent technique, X‐ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the anodic film formed on Pb mainly consists oft‐PbO, while that on Pb‐3at.%Sb consists of o‐PbO, t‐PbO and a small amount of orthorhombic Sb2O3. The dominant component of the film anodically grown on Pb‐3at.%Sb for less than 5 min is o‐PbO, however, t‐PbO is the major component of the anodic film formed for 1 h or longer. It is established that Sb suppresses the growth of t‐PbO. The anodic film formed on Pb‐3at.%Sb is less porous than that on Pb. The bandgap energies of t‐PbO and o‐PbO in the films were determined by photocurrent measurements to be 1.83–1.84 eV and 2.60 eV, respectively.
Oxyfunctionalization of ketones bearing α‐methylene group with piperidine oxoammonium salt. Synthesis of α‐diketones from monoketones
Authors: You‐Cheng Liu , Tan Ren , Qing‐Xiang Guo 
Published: September 2010

AbstractA facile method for the title transformation is described. The reaction of 2,2,6,6‐tetramethyl‐4‐methoxypiperidine oxoammonium chloride (1b) and ketones bearing α‐methylene group in acetonitrile proceeded smoothly to give the α‐oxyfunctionalized coupling products (6a‐h). These coupling products decomposed upon heating in acidic medium to produce α‐diketones (7a‐h) in good to excellent yields.
Synthesis of 2‐aryl‐3H‐indol‐3‐ones via trapping reaction in singlet oxygenation of 2‐arylindoles
Authors: Ke‐Qing Ling 
Published: September 2010

Abstract2‐Aryl‐3H‐indol‐3‐ones (3a‐o) have been synthesized via methanol trapping reaction in singlet oxygenation of 2‐arylindoles (1a‐o), followed by thermal decomposition of the resultant 2‐aryl‐2‐methoxy‐3‐oxo‐2,3‐dihydroindoles (2a‐o) in good yields.
Theory and application of cyclic voltammetry for measurement of fast electrode kinetics at microdisk electrode,
Authors: Bao‐Kang Jin , Jian‐Rong Zhang , Zu‐Xun Zhang 
Published: September 2010

AbstractAn analytical expression describing voltammetric behaviors responses at microdisk electrode for various diffusion conditions and degrees of reversibility is reported in this paper. Results of theoretical calculation made it possible to use cyclic voltammetry to evaluate heterogeneous rate constants under intermediate diffusion conditions. At relatively low scan rate, the distortion of current‐voltage can be reduced due to small iR drops and charging current. The effects of transfer coefficient, α, kinetic parameter, λ(=k0r/4D), and switching potential, εs, on potential peak separation are discussed in detail. The relationship obtained in this paper between potential peak separation and λ is in good agreement with that in Ref. 14, whose authors have got their results by using digital simulation technique. After the experiment of Fe(CN)4–6 oxidation, k0 and α were obtained by the theory of this paper. The result agrees with that in Ref. 19.
Enantiomeric separation of α‐phenylethylamine and its analogs by mixed chiral and achiral stationary phase
Authors: Liang‐Mo Zhou , Xue‐Liang Liu , Zhong‐Sheng Li , Qing‐Hai Wang , Dao‐Qian Zhu , Dong‐Hong Hu 
Published: September 2010

AbstractA mixed stationary phase of modified β‐cyclodextrin, 2,6‐di‐O‐butyl‐3‐O‐butyryl‐β‐cyclodextrin (phase A), and SE‐54 (phase B) was used for enantiomeric separation of α‐phenylethylamine,o,m,p‐methyl ando,m,p‐methoxy‐substituted analogs. The composition of mixed phase was selected by comparison of each calculated αmin(=(γm,i+1)/(γm,i)), the relative retention values of the most adjacent peaks, and γm, last, the relative retention values of the last eluting peak at each preselected ratio. Values of γ,i, a calculated by derived equations were in good agreement with the experimental results obtained with two specified mixed phases. All solutes investigated were almost baseline separated at a predicted composition of phase A and phase B in a single run within 18 minutes.
Studies on sulfinatodehalogenation: The reaction of polyfluoroalkyl iodides and bromides with sodium Bisulfite
Authors: Fan‐Hong Wu , Bing‐Nan Huang , Wei‐Yuan Huang 
Published: September 2010

AbstractWithout oxidant, sodium bisulfite reacted with polyfluoroalkyl iodides and bromides in aqueous DMF solution to give the corresponding sulfinates in good yields.
The band structures of some transition metals and their NaCl‐type compounds
Authors: Shu‐Hui Cai , Chun‐Wan Liu 
Published: September 2010

AbstractThe band structures of Group IVB (Ti, Zr, Hf), VB (V, Nb, Ta) and V1B (Cr, Mo, W) transition metals and some of their carbides and nitrides (TiN, ZrN, HfN, VC, NbC, TaC, VN, NbN, TaN) with NaCl‐type (Bl‐type) structure have been calculated by using the tight‐binding method within the Extended Hückel approximation (EHT). The energy bands, densities of states and crystal orbital overlap populations are given. The relationship between the bonding properties and the superconducting transition temperatures (Tc) of them is discussed. The influences of various kinds of metallic atoms and changes of bond lengths on Tc are also discussed.
Solvent effects on competitive intramolecular electron transfer and energy transfer in a covalently linked porphyrin‐phthalocyanine heterodimer
Authors: Hong‐Jian Tian , Qing‐Pu Zhou , Shu‐Yin Shen , Hui‐Jun Xu 
Published: September 2010

AbstractPhotophysical properties of a porphyrin‐phthalocyanine heterodimer covalently linked with a dipentoxy chain have been studied. Absorption spectra show that there is weak exciton coupling between the two chromophores in the ground state. Fluorescence spectra show that intramolecular energy transfer from porphyrin to phthalocyanine moiety occurs in competition with electron transfer. The efficiency of these two processes depends upon the mutual orientation of the two chromophores. The effect of solvent polarity on the intramolecular processes is also discussed.
Synthesis, characterization, antitumor activity of nickel(II) and cobalt(II) complexes of 2,2′‐diamino‐4,4′‐bithiazole and their interaction with dGMP
Authors: Yan‐Ni Tian , Pin Yang , Qing‐Shan Li , Chun‐Gui Zhao 
Published: September 2010

AbstractNew complexes, of bis(2,2′‐diamino‐4,4′‐bithiazole)sulfate nickel(II) and bis(2,2′‐diamino‐4,4′‐bithiazole)sulfate cobalt(II), have been prepared. The complexes were characterized by infrared and UV‐Vis spectroscopy, 1H NMR, elemental analyses and molar conductivity. The effect of these complexes on the DNA synthesis of sarcoma 180 cells has been studied by the technique of isotopic liquid scintillation. The results indicated that complexes show ability to inhibit DNA synthesis of the tumor cells. In order to provide a molecular basis for understanding the biological effects, the probe, [trans‐en2Os(2‐H2)](CF3SO3)2 (en, ethylenediamine) as a monitor was first used to explore interaction of the complexes with 2′‐deoxyguanosine‐5′‐monophosphate (dGMP).
Synthesis and reactions of 2‐[α‐(3,4‐disubstituted phenacyl)‐p‐substituted styryl]‐4H‐3,1‐benzoxazin‐4‐ones
Authors: Ahmed Youssef Soliman , Ibrahim Abd El‐Mogoud Attia , Moneer Abdu Ibrahim Salem , El‐Sayed Ahmed Soliman , Adel Mohy El‐Deen Gaber 
Published: September 2010

AbstractConversion of β‐aroyl propionic acids into furanone derivatives (2) and benzoxazinone derivatives (3) for the study of the reactivity of these nucleus towards different nucleophilic and electrophilic reagents.
Syntheses of a new type of chiral phosphines from glucose
Authors: Ji‐Cheng Shi , Ting‐Bin Wen , Da‐Xu Wu , Ge‐Tan Lu , Mao‐Chun Hong , Qiu‐Tian Liu , Bei‐Sheng Kang , Han‐Qing Wang , Shi‐Jie Lü 
Published: September 2010

AbstractMethyl 3‐deoxy‐3‐(diphenylphosphino)‐4,6‐O‐benzylidene‐α‐D‐altropyranoside (1) and methyl 2‐deoxy‐2‐(diphenylphosphino)‐4,6‐O‐benzylidene‐α‐D‐altropyranoside (2) were prepared from methyl 2,3‐anhydro‐4,6‐O‐benzylidene‐O‐D‐mannopyranoside and methyl 2,3‐anhydro‐4,6‐O‐benzylidene‐α‐D‐allopyranoside, respectively, via regioselective and stereospecific ring‐opening reactions in high yields. Compounds 1 and 2 were oxidized to give the corresponding phosphine oxides (S and 4).
A Barbier type reaction promoted by in situ formed active metal bismuth from NaBH4 and BiCl3 in aqueous media
Authors: Ping‐Da Ren , Shi‐Feng Pan , Ting‐Wei Dong , Shi‐Hui Wu 
Published: September 2010

AbstractIn the presence of active metal bismuth (Bi*) which was prepared from the combination of bismuth trichloride and sodium borohydride, aldehydes have been found to react with allyl bromide in aqueous media, and the corresponding homoallylic alcohols were obtained in excellent yields with high chemo‐and stereoselectivity.
Photochemical reaction of azobenzene in solvent‐swollen Nafion membranes
Authors: Chen‐Ho Tung , Jing‐Qu Guan 
Published: September 2010

AbstractThe photochemical reactions of azobenzene (AB) incorporated into different solvent‐swollen Nafion membranes were investigated. The location of azobenzene in water‐swollen Nafion membranes was different from that in methanol‐swollen Nafion membranes, which was responsible for the different photochemical reactions of AB. In methanol‐swollen Nafion membranes only trans↔cis isomerization took place, while in water‐swollen Nafion membranes photochemical cyclization of AB occurred after rapid trans↔cis isomerization. The relation between the relative quantum yields and the light intensity showed that the cyclization was a two‐photo process. The numbers of AB molecules per cluster (nAB/cluster) in Nafion membranes with different AB concentrations and different water contents were calculated. Under the experimental condition two competitive photocyclization mechanisms were suggested by nAB/cluster in Nafion membranes, relative quantum yields of the cyclization, and the change of the ratio of benzidine to benzo[c]cinnoline.
Palladium‐induced electron‐transfer reaction of difluorodiiodomethane with
Authors: An‐Rong Alkenes, Li , Qing‐Yun Chen 
Published: September 2010

AbstractThe addition reaction of difluorodiiodomethane (1) with alkenes in the presence of PdCl2(PPh3)2 or Pd(PPh3)4 afforded the corresponding iododifluoromethylated compounds in excellent yield.
Quantum chemical study on the thermal Diels‐Alder reaction of cyclohexadiene and methyl crotonate
Authors: Li Yong‐Hong , Hong San‐Guo , Wang Shen , Peng Yi‐Yuan 
Published: September 2010

AbstractAM1 molecular orbital method using the unrestricted Hartree‐Fock(UHF) calculations has been applied to investigate the thermal reaction of cyclohexadiene and methyl crotonate. The calculated results indicate that the thermal Diels‐Alder reaction proceeds to product through the concerted path and two radical pathways.
Study on the dual‐frequency oscillations in galactose‐BZ system
Authors: Li He‐Xing 
Published: September 2010

AbstractThree types of duel‐frequency oscillations in KBrO3‐galactose‐acetone‐SO4‐H2SO4 have been observed in a batch reactor depending on the initial concentration of H2SO4 or Br‐. Similar phenomena were also observed when galactose was replaced by other aldosugars such as glucose, arabinose, lactose and maltose. However no dual‐frequency oscillation has been found when ketosugar like fructose was used instead of galactose as the substrate. The roles of acidity, bromide ion and acetone in dual‐frequency oscillations have been analyzed. The mechanism of dual‐frequency oscillations has been discussed.
Mössbauer study of reactions of Sn[Fe(CN)6] on supports
Authors: Chen Shou‐Wen , Yang Xu‐Jie , Lu Lu‐De , Wang Xin 
Published: September 2010

AbstractMössbauer spectroscopy has been applied to the investigation of reaction of Sn(Fe(CN)6 on magnesia, γ‐alumina, silica and activated carbon. It wan found that the thermal decomposition products of supported Sn[Fe(CN)6] are quite different from those of the unsupported one as a result of the interaction between the complex and supports. The supports could promote the oxidation in the air atmosphere and their effect led to high dispersion of the decomposition products on the surface.
Incorporation of Fe(III) in framework of zeolite L
Authors: He Nong‐Yue , Bao Shu‐Lin , Xu Qin‐Hua 
Published: September 2010

AbstractZeolite L with Fe in lattice position is prepared from the gel with Fe/(Fe+Al) ratio up to 0.4 using ferric nitrate as Fe source. The incorporation of Fe(III) in framework is characterized by XRD, IR, TG/DTA, BET and Mössbauer spectroscopy. Zeolite L is destabilized by Fe(III) in framework and the reduction of Fe(III) in framework of (A1,Fe )KL was first reported.
Hypersensitivity and its application to structural analysis of lanthanide complexes
Authors: Yang Wu , Chen Miao , Gao Jin‐Zhang , Yang Wei‐Dong , Kang Jing‐Wan , Yang Hong‐Wu 
Published: September 2010

AbstractHypersensitivity of the ternary complexes Ln(β‐dik)4HMQ(where Ln=Nd, Ho, Er, β‐dik=acetylacetonate(AA), dibenzoylmethanate(DBM) and MQ=4‐methylquinoline) in acetone solution is studied based on the dynamic coupling model. The structures of these complexes in solution are deduced. Their coordination polyhydrons are all distorted square antiprism. Neodymium complexes have D2 symmetry, while holmium and erbium complexes have exact D2d symmetry.
A study of the quenching of PCl(b1Σ+) by the E‐V model
Authors: Liu Chuan‐Pu , Zou Sheng‐Li , Guo Jing‐Zhong , Gu Yue‐Shu , Chu Ym‐Na , Cao De‐Zhm 
Published: September 2010

AbstractUsing the reaction of Ar(3P0,2) + PCl3 as a source of PCl(b1Σ+), we have measured the quenching rate constants of PCl(b,v'=0) for more than 20 quenchers. The EV model is used to calculate the rate constants. The comparison of the calculated values with the experimental one shows that the quenching of PCl(b) by the reagent molecules results from the electronic to vibrational energy near resonance transfer and has been related to the Franck‐Condon factors for the PCl(b,v'=0 →a,v″=m) transition and to the anharmonicities of the terminal bonds of the quenchers. In addition, the influence of the polarizability of the reagent molecule on the quenching rate constant in discussed.
In vitro antitumor activity of titanocene alanine complex and its interaction with nucleic acids
Authors: Zhang Zhi‐Gag , Jin La , Yang Pin 
Published: September 2010

AbstractTitanocene alanine complex, Cp2Ti(O2CCH(CH3)NH+3CI−)2, haa been found to have in vitro antitumor activity against Ehrlich ascites tumor cells. Study of the interaction between Cp2Ti(O2CCH(CH3)NH+3CI−)2 and DNA by UV‐VIS spectra, fluorescence spectra, agarose gel electrophoresis reveals that Cp2Ti(O2CCH(CH3)NH+3Cl−)2 form a stable compound with DNA in molar ratio 1:1 and reduces the migration rate of ccc‐DNA band and oc‐DNA band. However, unlike cis‐platin, the complex does not induce nicking of DNA even after a long incubation at a high ratio of the complex to DNA. The results suggest that titanocene‐based antitumor agents have different mechanism of action from cisplatin‐like antitumor agents.
Synthesis, luminescence properties and energy transfer of binary and ternary rare earth complexes with aromatic acids and 1,10‐phenanthroline
Authors: Yan Sing , Zhang Hong‐Jie , Ni Jia‐Zuan 
Published: September 2010

AbstractA series of binary and ternary ram earth (Gd, Eu, Tb) complexes with ortho hydroxyl benzoic acid, para aminobenzoic acid, nicotinic acid and 1,10‐phenanthroline were synthesized. Phosphorescence spectra and lifetimes of Gd complexes were measured and the lowest triplet state energies of gadolinium binary complexes and the intramolecular energy transfer efficiencies were determined. The luminescence properties and energy transfer process of Eu3+and Tb3+ complexes were discussed.
A facile synthesis of per(poly)fluoroalkyl substituted α‐amino acid derivatives
Authors: Hu Qiao‐Sheng , Hu Chang‐Ming 
Published: September 2010

AbstractInitiated by CrCl3/Fe redox couple, per(poly)fluoroalkyl iodides added to methyl α‐acetylamino acrylate, giving β‐per(poly)fluoroalkyl α‐amino acid derivatives in good yields.