bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses of (C5H9C5H4)2LnCl(THF)n (Ln = Nd, Sm, Er, Yb) and crystal structure of [(C5H9C5H4)2‐LnCl(THF)n]2(Ln = Sm, n = 1; Ln = Er, n = 0)
Authors: Jin Ji‐Zhu , Jin Zhong‐Sheng , Wei Ge‐Cheng , Chen Wen‐Qi
Published: September 2010

Reactions of lanthanoid trichlorides with sodium cyclopentylcyclopentadienyl in THF afford bis(cyclopentylcyclopentadienyl)lanthanoid chloride complexes (C2H9C5H4)2 LnCl(THF)n (Ln = Nd, Sm, n = 1; Ln = Er, Yb, n = 0). The compound [Cp'2SmCl(THF)]2 (2) (Cp' = cyclopentylcyclopentadienyl) crystallizes from mixed solvent of hexane and THF in monoclinic space group P21/c with a = 11.583 (3), b = 23.019(6), c = 8.227 (2) Å, β = 90.26 (2)°, V= 2194 (1)Å2, Dc = 1.59 g / cm3, μ = 28.6 cm−1, F(000) = 1060, Z = 2 (dimers). Its crystal molecule is a dimer with a crystallographic symmetry center. The central metal atom Sm is coordinated to two Cp' rings, two bridging chlorine atoms and one THF forming a distorted trigonal bipyramid. The crystal of [Cp'2ErCl]3 (3) belongs to the triclinic space group P1 with a = 11.264 (2), b = 13.296(5), c = 14.296(6)Å, α = 96.99 (3), β = 112.47(2), γ = 102.78(2)°, V = 1865(1)Å2, De = 1.67 g / cm2, μ = 48.0 cm−1, F(000) = 924, Z = 2 (dimers). The molecule is a dimer consisting of two Cp'2 ErCl species bridged by two Cl atoms. The central metal atom Er is coordinated to two Cp' rings and two bridging chlorine atoms forming a pseudotetrahedron. All these complexes are soluble in THF, DME, Et2O, toluene and hexane.
Study on the cocolouration effect in the β‐complex formation reactions of rare earths with p‐chloro‐chlorophosphonazo (CPApC)
Authors: Xu Zhong‐Jun , Hsu Chung‐Gin , Zhang Lan , Pan Jiao‐Mai
Published: September 2010

Terbium‐ and yttrium‐group rare earths form β‐complexes with CPApC in acidic medium. The sensitivities for determination of these rare earths by this reaction depend on their ionic radii. Cerium‐ or terbium‐group rare earth in the presence of yttrium‐group element produces the cocolouration effect which remarkably sensitizes the reaction. Yb‐CPApC‐Eu complex has a molar composition of 1:4:2 and gives a molar absorptivity of 2.02×103 L·mol−1·cm−1 at 746 nm for Eu. It is found that the closer the lengths of ionic radii of the rare earths are, the greater will be the cocolouration effect.
Investigation on chiral capillary columns and their application in separation of enantiomers
Authors: Zhou Liang‐Mo , Lou Xian‐Wen , Liu You‐Qin , Wang Qing‐Hai , Zhu Dao‐Qian
Published: September 2010

Six chiral diamide stationary phases (CSPs), namely N‐(3‐carbobenzoxypropionyl)‐L‐Val‐tert‐butylamide (CSP‐1), N‐undecenoyl‐L‐Val‐S‐α‐phenylethylamide (CSP‐2), N‐undecenoyl‐L‐Val‐R‐α‐phenylethylamide (CSP‐3), OV‐225‐L‐Val‐tert‐butylamide (CSP‐4), XE‐60‐L‐Val‐tert‐butylamide (CSP‐5) and polycyanoethyl vinyl siloxane‐L‐Val‐tert‐butylamide (CSP‐6), were investigated and CSP‐6 was crosslinked within narrow bore (70 μm) fused silica capillary columns. The separation of amino acid enantiomers on this narrow bore column by gas chromatography (GC) is illustrated.
Asymmetric syntheses of α‐amino acids via double chiral induction in alkylation of the ketimine derived from 2‐hydroxypinan‐3‐one and menthyl glycinate
Authors: Mi Ai‐Qiao , Ma Zeng‐Xin , Wu Lan‐Jun , Jiang Yao‐Zhong
Published: September 2010

Asymmetric syntheses of (S)‐α‐amino acids in 28–98% optical yields via double chiral induction in alkylations of ketimine 1 derived from (+)‐2‐hydroxypinan‐3‐one and (‐)‐menthyl glycinate which is a chiral match pair have been studied. The factors controlling the diastereoselectivities in alkylation reactions of the ketimine, the properties of alkylating agents and various alkylation conditions are examined.
Addition of polyfluoroalkyl halides to 1‐octene initiated by dichlorobis(π‐cyclopentadienyl)‐titanium and iron
Authors: Hu Chang‐Ming , Qiu Yao‐Ling
Published: September 2010

Addition of various polyfluoroalkyl halides including 1,2‐dihalopolyfluoroalkanes to 1‐octene is effected by using a catalytic amount of Cp2TiCl3(IV) and iron powder to give 1:1 adducts in excellent yields. The reaction is performed in EtOH or THF. A Cp2TiCl(III) mediated radical mechanism is proposed. Radical reactivity of polyfluoroalkanes toward 1‐octene was found to be ‐CF2I>‐CF2Br>‐CF2CCl2.
Vanadium(IV) dimer complexes containing [V(o‐C6H4OS)3]2− fragment and caged sodium ions
Authors: Weng Lin‐Hong , Kang Bei‐Sheng , Chen Xue‐Tai , Hong Mao‐Chun , Lei Xin‐Jian , Hu Yong‐Han , Liu Han‐Qin
Published: September 2010

Tris[o‐mercaptophenolato]vanadium(IV) dimer complexes (A)2[V(mp)3NaLL']2 (A = Ph4P+, H2mp = o‐mercaptophenol, L = MeCN, L'=EtOH, (1); L' = MeOH, (2)) were prepared by the reaction of anhydrous VC13, and Na2mp in the molar ratio 1:3. Complex (3) (A = Et4N+, L=L' = MeOH) was prepared by the reaction of VC13, Na2mp and Li2S in the molar ratio 1:2:1. The complexes were characterized by X‐ray diffraction crystallography, infrared spectra, magnetic susceptibility, and cyclic voltammetric measurements. Complex 2 crystallizes in the triclinic space group P1 with a=12.813(6), b = 14.199(4), c = 12.790(5) Å, α = 112.72(2), β = 104.24(4). γ = 88.68(4)°, V = 2073.6 Å3, and Z=1. The structure was refined to R=0.058. Complex 3 crystallizes in the mono‐clinic space group P21/n with a=12.359(3), b=17.452(6), c=14.829(13) Å, βequals;96.51(5)°, V=3177.8 Å3, and Z=2. The final R factor is 0.067. Both of the anions of 2 and 3 contain two [V(mp)3]2− fragments linked by sodium ions through the μ3‐O bridges with a crystallographic center of symmetry. The V(IV) atom is in a coordination environment intermediate between a trigonal prism and an ideal octahedron.
Computer‐assisted optimization for the selection of mobile phase in semi‐preparative HPLC
Authors: Wang Qin‐Sun , Gao Ru‐Yu , Yan Bing‐Wen
Published: September 2010

A computer‐assisted method is presented for optimization for the selection of mobile phase composition in semi‐preparative HPLC. The optimization for the expected separation is based on a polynomial estimation from five preliminary runs. Statistical scanning technique was used for optimization. Double criteria simulation system (DCSS) is established for chromatographic performance measurement in this method. The validity of the optimization strategy is confirmed by applying it to a technical Cypermethrin separation. Excellent agreement is obtained between the predicted and experimental results.
The correlation between molecular structure parameters of O‐ethyl N‐isopropyl phosphoro(thioureido) thioates and their retention data in RP‐HPLC
Authors: Wang Qin‐Sun , Gao Ru‐Yu , Yang Hua‐Zheng , Yan Bing‐Wen
Published: September 2010

A retention prediction system (RPS) of seven O‐ethyl N‐isopropyl phosphoro(thioureido)‐thioates in reversed phase HPLC was investigated. The system is based on the solvent selectivity triangle concept. Three molecular structure parameters (hydrophobicity II, substituent length L, and substituent maximum with B5) were used to describe the quantitative structure‐retention relationships. With these quantitative relationships, the retention behaviours of other eight homologs for different mobile phase composition were predicted. The predicted values were consistent with the measured values within relative error of 10%, which means that it is possible to apply the reported method to predict retention values for qualitative purposes for different mobile phase compositions.
Stereospecific synthesis of (E)‐furfurylalkenes from alkenyldisiamylboranes and furfuryl chloride
Authors: Li Nan‐Sheng , Chen Yan , Deng Min‐Zhi
Published: September 2010

The Pd(PPh2)4‐catalyzed coupling reaction of alkenyl‐disiamylboranes with furfuryl chloride in the presence of f‐BuOK afforded (E)‐furfurylalkenes stereospecifically in good yields.
Influence of chemical dealumination on the properties of USY zeolite
Authors: Bao Shu‐Lin , Wu Peng , Xu Qin‐Hua
Published: September 2010

Three series of dealuminated Y zeolites have been prepared by chemical extraction of hydrothermally dealuminated Y zeolite (USY) with H2Na2EDTA, HCl and H4EDTA. The unit cell constant, mesopore distribution, acidity and extraframework aluminum (EFAL) of the zeolites were studied with XRD, chemical analyses, adsorption, IR and NH3‐TPD techniques. It was shown that H2Na2EDTA only removed EFAL species deposited in the pores of USY, by contrast, HCl and H4EDTA extract both extraframework and framework aluminum, and make the zeolite framework further dealuminated. Adsorption tests gave evidence that a secondary pore system exists in these dealuminated zeolites. H2Na2EDTA extraction increased both micropore and mesopore volumes, but after HCl and H4EDTA treatments, new mesopores formed and the micropore volume was decreased. The pyridine‐IR and NH3‐TPD measurements demonstrated that EFAL had no evident contribution to the zeolite acidity.
Studies on macrocyclic diterpenoids. V. Synthesis of (±)‐sarcophytol‐A benzyl ether
Authors: Li Wei‐Dong , Li Ying , Mao Jian‐Min , Li Yu‐Lin
Published: September 2010

The title compound, sarcophytol‐A benzyl ether has been synthesized through 13 steps by employing acetone and geraniol as starting materials. The key steps in the synthesis were double bond migration reaction of allylic alcohols 5 and 6, phase transfer catalytic coupling (PTC) reaction of II with 7 and the cyclization reaction of dicarbonyl acyclic precursor induced by TiCl3‐AlCl3(3:1)/Zn‐Cu system.
Studies on polyhaloalkanes. I. Radical addition of polyfluoroalkyl iodides to diethyl allylphosphonate
Authors: Huang Bing‐Nan , Wang Ke‐Yang , Huang Wei‐Yuan , Prescher Dietrich
Published: September 2010

Radical addition of polyfluoroalkyl iodides to the CC double bond of diethyl allylphosphonate was carried out in CH2Cl2‐H2O two‐phase medium in the presence of sodium dithionite to give diethyl 3‐polyfluoroalkyl‐2‐iodopropylphosphonates (3) in excellent yields. Compounds 3 were then converted to diethyl polyfluoroalkanephosphonates (4) by zinc‐reduction. Thus a facile method for preparing polyfluoroalkanephosphonates is realized.
Isomerization kineties of spirocompounds incorporated into sodium dialkylmethyl sulfate bilayer membranes
Authors: Wang Guan‐Wu , Lei Xue‐Gong , Li Zi‐Zhong , Liu You‐Cheng , Fan Mei‐Gong
Published: September 2010

The isomerization kinetics of a spiropyran (1) and a spirooxazine (2) embedded in bilayer membranes of sodium 1‐pentadecylhexadecyl sulfate (3) and sodium 1‐undecyl dodecyl sulfate (4), respectively, were investigated. The thermal decay of 2 obeyed first‐order kinetics, whereas that of 1 consisted of two simultaneous first‐order processes. Kinetic parameters; were obtained from Arrhenius plots.
A novel mixed‐coordination cobalt(III)complex:synthesis and structure of Co(III)(mpp)(Hmpp)(n‐Bu3P)2
Authors: Xu Yong‐Jin , Kang Bei‐Sheng , Chen Xue‐Tai , Hu Yong‐Han
Published: September 2010

Complex Co(III)(mpp)(Hmpp) (n‐Bu3P)2 (1. H2mpp= 2‐mercapto‐3‐pyridinol) was obtained from the reaction of CoCl2 with H2mpp, n·Bu3P and Na metal in EtOH. The Co atom in a distorted octahedral geometry is coordinated with donor atoms N, O, P and S. The two H2mpp ligands form two different chelate rings with the Co(III) ion: one 5‐membered and the other one 4‐membered, while the two n‐Bu3P ligands are in the axial positions with the angle P(1)‐Co‐P(2) of 176.1:
Structural elucidation of sex pheromone components of the Geometridae Semiothisa cinerearia (Bremer et Grey) in China
Authors: Li Zheng‐Ming , Yao En‐Yun , Liu Tian‐Lin , Liu Zi‐Ping , Wang Su‐Hua , Zhu Hai‐Qing , Zhao Gang , Ren Zi‐Li
Published: September 2010

An extract from the female sex gland of Semiothisa cinerearia attracted conspecific males in field tests. A major active component was isolated from the extract and identified by GC‐MS, GC‐IR and microchemical reactions as cis‐3,4‐epoxy‐(Z,Z)‐6. 9‐heptadecadiene, which showed strong EAG response. Another minor yet important component was identified as (Z,Z,Z)‐3,6,9‐heptadecatriene.
A novel regio‐ and stereo‐specific hydrohalogenation reaction of 2‐alkynoic acids and their derivatives
Authors: Lu Xi‐Yan , Zhu Guo‐Xin , Ma Sheng‐Ming
Published: September 2010

The nucleophilic hydrohalogenation of 2‐alkynoic acids and their derivatives by heating with lithium halides in HOAc afforded the thermodynamically unfavorable 3‐halo‐2 (Z)‐alkenoic acids and their derivatives stereospecifically
The three‐dimensional structure of trichosanthin refined at 2.7 Å resolution
Authors: Xia Zong‐Xiang , Zhang Lei , Zhang Zhi‐Ming , Wu Shen , Dong Yi‐Cheng
Published: September 2010

The three‐dimensional structure of trichosanthin crystallizing in space group C2 has been refined at 2.7 Å resolution from a previously reported starting model at 3 Å resolution based on a solvent flattened map and the revised primary structure consisting of 247 amino‐acids. The final R‐factor is 19.2% with the root mean‐square deviations of 0.018 Å from ideal bond lengths and of 2.2˙ from ideal bond angles. Trichosanthin molecule is composed of two domains, the large domain consisting of 181 amino‐acid residues starting from N‐terminus and the small domain consisting of the rest of the amino‐acid residues. The molecule contains eight α‐helices. five β‐sheets made of sixteen β‐strands, and some reverse turns. It is noteworthy that some of the α‐helices and β‐sheets show irregular hydrogen bonding patterns. Six of the thirteen residues absolutely conserved in eleven ribosome‐inactivating proteins are located in a cleft near the interface of the two domains and they are likely to be active sites. Three additional conservative residues located in the cleft region might make some functional contribution as well.
A theoretical analysis and its application of the second order EC reactions at microelectrodes under steady‐state conditions
Authors: Zhuang Qian‐Kun , Chen Hong‐Yuan
Published: September 2010

With a new approach, the general current expressions of two typical second order catalytic reactions are obtained for disk, hemispherical and spherical microelectrodes under steady‐state conditions. This approach is based on the concept of reaction layer. For the second order EC reactions, we also discussed how it is possible to observe pseudo‐first order or second order behavior. This consideration allows the study of the fast chemical reactions and systems where the bulk concentrations of the reactants are nearly equal. Regeneration of Fe3+(EDTA) with H202 was selected as an example of a rapid catalytic reaction.
The isotopic effects in the IR‐multiphoton excitation of molecules with c2v symmetry
Authors: Ding Shi‐Liang , Liu Wen‐Jian , Deng Cong‐Hao
Published: September 2010

Quantum dynamical calculations for the IR‐multiphoton excitation of H2O, D2O and T2O are presented using a generalized Hamiltonian for XY2 molecules. The energy spectra obtained from this Hamiltonian are in good agreement with those of the experiments. The long time average of the transition probabilities and the isotopic effects are discussed in detail,
An unexpected Diels‐Alder type cycloaddition of cyclic enone ethylene ketals
Authors: Chow Yuan L. , Cheng Xian‐En , Zhang Yu‐Huang
Published: September 2010

The ethylene ketal of 2‐cyclopentenone and 2‐cyclohexenone in acetonitrile in the presence of a trace of an acid rapidly undergoes the Diels‐Alder type dimerization. The products are regiospecific but not stereoselective and are hydrolysed sequentially to afford keto‐ketals and diketones whose structures are determined by extensive applications of NMB spectroscopy.
Crystal and molecular structure of 2,3‐benzo‐1,4,7,13‐tetraoxa‐10‐selenacyclopentadeca‐2‐ene
Authors: Xu Han‐Sheng , Li Wei‐Ping , Liu Xiu‐Fang , Huang You‐Qing , Hu Sheng‐Zhi
Published: September 2010

The crystal structure of 2,3‐benzo‐1,4,7,13‐tetraoxa‐10‐selenacyclopentadeca‐2‐ene was determined. C14H20O4Se, Mr=331.27, orthorhombic, Pbca, a=18.445(3) Å, b=16.334(4) Å, c=9.232(2) Å, V=2781.3 Å3, Z=8, Dx=1.582 Mg m−3, λ(Mo Kα)equals;0.71073 Å, μequals;26.77 cm−1, F(000)equals;1360, T=297 K, R=0.0329, Rw =0.0438 for 2192 reflections with I > 3 s̀(I). The crystal structure is closely related to that of benzo‐15‐crown‐5 (at 123 K), whereas the molecular geometry of the two coronands is different according to their torsion angles calculated and the shapes exhibited.
Reactions of magnesium formate on supports
Authors: Han Qiao‐Feng , Yang Xu‐Jie , Deng Li‐Jun , Wang Xin , Lu Lu‐De , Hua Wan‐Sheng
Published: September 2010

Thermal decomposition of supported magnesium formate has been studied by gas chromatography. The reaction paths of decomposition of supported magnesium formate depend on the nature of the supports. For Mg(HCO2)2/HZSM‐5, the zeolite behaves as a dehydration catalyst to give CO and H2O at lower temperatures; when the zeolite is modified by phosphorus, the methanation reaction will be partly restrained. In the case of Mg(HCO2)2/AC, strong adsorption of CO2 leads to the formation of the shoulder peak of CO2 at higher temperatures, however, CH4 disappears after modified by phosphorus. For Mg(HCO2)2/Al2O3, the dehydrogenation of HCO2− takes place on the surface of Al2O3. The decomposition of Mg(HCO2)2 on SiO2 in hydrogen yields two peaks of CO and only one appears after modified by phosphorus. When Mg(HCO2)2 decomposes on MgO, the first peak of CO2 arises from the reaction of surface Mg2+ with HCO2− from dissociated Mg(HCO2)2.
Studies on solid state reactions of coordination compounds. LXIII. Solid state synthesis of a series of tetranuclear Mo(W)—Ag mixed‐metal clusters. Crystal structures of [(n‐Bu)4N]3[MoOS3Ag3Br4] and [(n‐Bu)4N]3[WS4Ag3Cl4]
Authors: Lang Jian‐Ping , Xin Xin‐Quan , Cai Jin‐Hua , Kang Bei‐Sheng
Published: September 2010

A series of tetranuclear Mo(W)‐Ag mixed‐metal clusters have been synthesized by making use of the solid state reactions of [NH4]2[MYS3](M= Mo, W; Y= O, S), AgX(X= Cl, Br, I) and (n‐Bu)4NX' (X' =Cl, Br), two of which [(n‐Bu)4N]3[MoOS3Ag3Br4] (1) and [(n‐Bu)4N]3[WS4Ag3Cl4] (2) have been structurally characterized by X‐ray analysis. The crystal data: 1, cubic, P43m, αequals;12.093(4) Å, Z=1, R =0.076; 2, cubic, P43m, αequals;12.059(2) Å, Z =1, R =0.075. The cluster anion core [Ag3MS3X'] of the two compounds can be viewed as a cube in which the four metal atoms and the four non‐metal atoms are statistically distributed, respectively. Substitution reaction with PPh3 ligand is also discussed for this type of tetranuclear clusters.
Single‐Li+ conductivity in ionomeric network
Authors: Zhang Sheng‐Shui , Liu Qing‐Guo , Yang Lei‐Ling , Farrington Gregory C.
Published: September 2010

Ionomeric networks (IN) with lithium sulfate and salt‐solvating oligo(oxyethylene) chain were synthesized on the purpose of improving the conductivity of single‐Li+−ionic conductors. Li+−ionic conductivity depends considerably on the salt content of the INs although the apparent degree of cross‐linking is fixed in a constant of 10 mol%. As salt content (Li/O value) equals 0.0467, conductivity of the IN containing neither small‐molecular salt nor low molecular weight plasticizer reaches a maximum of 7×10−6 S/cm at 25°C. Temperature‐conductivity relationship of the INs shows curved Arrhenius plots, suggesting that the ionic conduction is primarily influenced by segmental motion of the polymer host. In addition, WLF (Williams‐Landel‐Ferry) equation is used to analyze the conductivity data, from which the related WLF parameters are determined.
Kinetic and mechanism of oxidation of thiocarbohydrazide and its metal complex by acid bromate in aqueous and partial aqueous media
Authors: Pardhasaradhi V. , Hegde A. Chitharanjan , Gowda B. Thimme
Published: September 2010

The kinetics of oxidation of thiocarbohydrazide in the free and zinc(II)‐bound states by acid bromate have been studied in aqueous and water‐acetic acid (1:1, V/V) media under varying conditions, both in the absence and presence of added bromide ion. The rates of oxidations show first order kinetics in [bromate] in all the cases, but exhibit different kinetic behaviour in [substrate] and [H+]. Oxidation of TCH in aqueous medium shows zero order in [TCH] and nearly second order in [H+], while oxidation in aqueous acetic acid shows two ranges in [H+]. The rate shows first and fractional order kinetics in [TCH] in the first and second acid ranges. Kinetics observed in the presence of Br− are similar to those observed for oxidation of TCH in second acid range. In addition, the reaction shows fractional order in [Br−]. Oxidation of TCH in Zn(II)‐bound state exhibits first order kinetics in [substrate] and second order in [H+]. Increase in ionic strength of the medium decreases the rate in all the cases. Increase in acetic acid composition of the solvent increases the rate. Mechanisms consistent with the observed results have been considered and the rate laws deduced. The rate limiting steps have been identified and the coefficients of these steps have been calculated at different temperatures. The related activation parameters have also been computed. The validity of the deduced rate laws has also been tested by recalculating the rate constants from them as [TCH] and [H+] are varied.
Benzoylation of benzene and substituted benzenes catalyzed by superacid ZrO2:H2SO4
Authors: Jia Cheng‐Guo , Huang Mei‐Yu , Jiang Ying‐Yan
Published: September 2010

Superacid ZrO2:H2SO4 showed high activity in Friedel—Crafts benzoylation of benzene and substituted benzenes such as chlorobenzene, toluene and 1,3,5‐trimethylbenzene. Benzophenones in 90–100% yields were obtained with catalytic amount of superacid ZrO2:H2SO4. The calcination temperature greatly influenced the acid strength and activity of the superacid ZrO2:H2SO4. The superacid has both Lewis and Bronsted acid sites. The reversibility of Friedel—Crafts benzoylation and transacylation were observed over the superacid. The used superacid could be readily regenerated and showed identical benzoylation activity to toluene.
Studies on the biosynthesis of arteannuin. IV. The biosynthesis of arteanniuin and arteannuin B by the leaf homogenate of Artemisia annua L.
Authors: Wang Yu , Xia Zhi‐Qiang , Zhou Feng‐Yi , Wu Yu‐Lin , Huang Jing‐Jian , Wang Zhi‐Zhong
Published: September 2010

Arteannuic acid and (‐)11R,13‐dihydroarteannuic acid are the key intermediates in the biosynthesis of arteannuin by the leaf homogenate of Artemisia annua L., and arteannuic acid and epoxyarteannuic acid are the intermediates of arteannuin B. and epoxyarteannuic acid can not be transformed into arteannuin by the homogenate.
Localized molecular orbital studies of certain compounds with [A3X3] six‐membered rings
Authors: Li Jun , Liu Chun‐Wan , Lu Jia‐Xi
Published: September 2010

The localized molecular orbitals (LMOs) of certain quasi‐aromatic organic and inorganic molecules with six‐membered rings have been calculated by virtue of the ab initio method using STO‐3G and 4–31G basis sets as well as the CNDO/2 method. It is shown that there exists extensively‐delocalized p‐pπ bonding in these quasi‐aromatic systems. The localized pictures of the π‐type LMOs for the heterocyclic and homocyclic systems from the σ‐π localization scheme are discussed. The Generator Orbital approach is utilized to account for the bonding patterns.
Structure effect of nucleotides in terbium(III)—nucleotide fluorescent reaction New evidence for the binding sites of terbium(III) on nucleotides
Authors: Li Yuan‐Zong , Chang Wen‐Bao , Ci Yun‐Xiang
Published: September 2010

Upon addition of Tb3+ to 16 nucleotides and homopolynucleotides, all of them showed a characteristic green emission from Tb3+, but with much different intensity, upon excitation in the aromatic region of bases. The result suggested that nucleotides with at least one carbonyl group in nucleotide bases are better enhancers to the fluorescence of Tb3+. The complexes of ATP, GDP and GTP with Tb3+ are synthesized as two types of models. Guanine type nucleotides with one carbonyl group in the bases are the best enhancers, while adenine type nucleotides with no carbonyl group in the bases are poorest enhancers to the fluorescence of Tb3+. Comparing the IR spectra of ATP, GTP, GDP and their Tb3+ complexes suggested that C‐6 carbonyl group in GTP and GDP may be involved in complex formation, which may be responsible for the effective energy transfer. This is further supported by comparing the UV spectra of ATP, Poly(A), GTP, and Poly(G) with their Tb3+ complexes in water solution.
Complexation of hypocrellins and bivalent metals and one‐electron reduction of the complexes with electron donor
Authors: An Jing‐Yi , Tian Fei , Hu Yi‐Zhen , Jiang Li‐Jin
Published: September 2010

The complexation of HA (or HB) with bivalent metals was examined by UV‐Vis and NMR spectroscopy, and all of the complexes obtained have a metal‐ligand ratio of 1:1. The photoinduced reduction of the complexes of HA‐Zn2+ and HA‐Mg2+ (or HB‐Zn2+, HB‐Mg2+) in the presence of 1‐benzyl‐1,4‐dihydro‐nicotinamide as the electron donor was investigated by UV‐Vis and ESR spectroscopy. The studies demonstrated that illumination of the complexes of HA(HB)‐Zn2+ and HA(HB)‐Mg2+ led to the accumulation of the chelated semiquinone radical anions.
Amino acid identification and sequence analysis of peptides by reaction mass spectrometry
Authors: Yang Hou‐Jun , Hu Xiao‐Yu , Chen Yao‐Zu
Published: September 2010

Fast atom bombardment mass spectrometry (FAB‐MS) is applied to distinguish N‐terminal series ions from C‐terminal series ions of a peptide by on‐probe acetylation, it provides valuable information about the sequence of an unknown peptide. The FAB mass spectra contain a number of characteristic ions at low‐mass region in addition to the sequence ions at high‐mass region. It was found that the ions below m/z 200 are characteristic of the amino acid composition of the peptide, from which the amino acid composition of the peptide could be estimated. Additionally, mixture analysis is also discussed.
Enrichment of trace cerium subgroup rare earths by means of ion flotation
Authors: Liang Shu‐Quan , Ma Hui‐Min
Published: September 2010

The possibility of ion flotation of cerium subgroup rare earths (Ce‐subgroup), was explored. Various factors affecting the. flotation efficiency were investigated. The results showed that, by using sodium tetradecyl sulfate as the collector of trace Ce‐subgroup and frother, over 95% of Ce‐subgroup at ng/g levels could be separated from pH 2.3 media in 10—15 min. The proposed method has been applied to the determination of Ce‐subgroup in a polluted farmland soil reference material (GBW 08303) with satisfactory results.
A strategy for synthesis of polymer‐protective bimetallic colloids
Authors: Wang Yuan , Gui Lin‐Lin , Tang You‐Qi
Published: September 2010

A strategy for the synthesis of polymer‐protective bimetallic sols is proposed which has the advantage of the strong protective effect of the polymer agent on one of the composites to stabilize the bimetallic colloidal particles. This strategy is certified to be useful to the predication of the formation of stable bimetallic colloids protected by polymer and to the control of the particle size to a certain extent. A series of new PVP‐protective bimetallic colloidal dispersions containing noble metal element (Pt, Rh, Pd), light transition metal element (Co, Fe), and boron are obtained from the corresponding salts by the methods of reduction by stage and coreduction, using the NaBH4 as reductant. The TEM, XRD and EPMA measurements indicate the formation of bimetallic colloids. An interesting kind of coil aggregation is observed in the systems of PVP‐Pt‐Co and PVP‐Rh‐Co prepared by the method of reduction by stage.
Ab initio study on mechanisms of singlet oxygen reaction with ethylene
Authors: Chen De‐Zhan , Chen Bao‐Ji , Ning Shi‐Guang
Published: September 2010

The reaction of singlet oxygen with ethylene has been studied at the ab initio level with both HF/3–21G and HF/6–31G* basis sets, fully optimizing the geometries of the critical points. The transition state leading to the intermediate peroxirane from the initial reactants is found, located at 81.71 kJ/mol above the dissociation limit The vibrational analysis is done with two basis sets. From the results it can be seen that the frequencies have not been made an improvement obviously with augmented 6–31G* compared to 3–21G basis; it follows that main reason for too high HF/3–21G frequency could mainly be the vibrational anharmonicity. The eigenvector corresponding to the single imaginary vibrational frequency is dominated by the larger O—O distance. The finding of the transition state confirms that the peroxirane minimum can be reachable passing through a peroxirane‐like saddle point. In addition, the mechanisms of the reaction forming oxirane are discussed as well.
Preparation and spectroscopic properties of 2′,5′‐dideoxynucleosidylcobalamins
Authors: Yan Hong , Chen Hui‐Lan , Sun Hong‐Zhe , Xie De‐Ping , Tang Wen‐Xia
Published: September 2010

Two new coenzyme B12 analogues, 2′,5′‐dideoxycytidylcobalamin (2a) and 2′,5′‐dideoxyuridinylcobalamin (2b), and two others, 2′,5′‐dideoxyadenosylcobalamin (2c), and 5′‐deoxythymidylcobalamin (2d) were prepared by an improved method. All the four analogues were investigated by UV‐vis and 2D 1H NMR spectroscopy. The comparisons and discussion about their spectroscopic properties were done.
Synthesis of adamantane on zeolite catalysts
Authors: Gao Zi , Yang Xiao‐Bo
Published: September 2010

The synthesis of adamantane from tetrahydrodicyclopentadiene on zeolites with different framework structures was studied. The adamantane yield on HY zeolites is higher than on HM and HZSM‐5 zeolites. Among various types of dealuminated HY zeolites the HEY and HUSY zeolites give higher adamantane yields than conventional HY zeolite. The changes in activity and selectivity of the main and side reactions are correlated with the acidity and the pore structure of the zeolites. To ion‐exchange the HY and HUSY zeolites with Ni2+ and La3+ cations may further improve the activity and selectivity of the zeolite catalysts.
A study of vitamin A radical cation generated by chemical and radiolytic oxidation
Authors: Guo Qing‐Xiang , Ren Tan , Li Bin , Wang Jun , Liu You‐Cheng , Tu Tie‐Cheng , Dong Ji‐Rong
Published: September 2010

Electron transfer reaction between vitamin A (1) and tris(p‐bromophenyl)aminium bexachloroantimonate (2) in dichloromethane (DCM) has been investigated by means of UV‐VIS absorption and ESR spectroscopy. The title radical cation formed in the reaction was characterized by a new absorption band around 600 nm and a singlet unresolved ESR spectrum with g factor of 2.0038–2.0039 and line width of 20 G. Further studies indicated that ESR pattern and parameters of the radical cation generated by γ‐irradiation of 1 in CFCl3 matrix at 77 K are consistent with that resulted in the chemical oxidation in DCM at ambient temperature.
A study on the reaction of 2′‐hydroxychalcones with I2‐H2SO4‐DMSO system
Authors: Zhang Fang‐Jie , Li Yu‐Lin
Published: September 2010

The reaction of 2′‐hydroxychalcones with I2‐H2SO4‐DMSO system has been studied. The results obtained by us are entirely different from those reported in the literature. The mechanism of this reaction has also been investigated.
Study on the alkylation reaction of guanine and N‐acetylguanine and the synthesis of 1′‐C alkylated carba‐DHPG analogues
Authors: Liu Yu‐Gang , Fei Chang‐Pei , Chan Tak‐Hang
Published: September 2010

The alkylation reaction of guanine and N‐acetylguanine with model compounds such as isopropyl bromide or 4‐heptyl tosylate were studied. The reaction conditions such as temperature, solvent, base, and catalyst were examined for their effects on the reaction rate, and the yield and regioselectivity of the coupling reaction. The highest yield was obtained by using DMSO as the solvent. The reaction proceeded in a homogenous manner to give higher yield of 9‐N and 7‐N substituted product in a mole ratio of 1:1. The ratio could be raised to 2:1 if dibenzo‐18‐crown‐6 was used as a catalyst. Using the above procedure, three carba‐DHPG analogues bearing different 1′‐C alkyl side chains were synthesized.
Electrochemical behavior of C60 modified electrode in aqueous solutions
Authors: Shi Zhan‐Ling , Mao Yi‐Ping , Tong Wei , Jin Li‐Tong
Published: September 2010

The construction of adsorptive type Ceo modified electrode and its electrochemical reduction and oxidation behavior in aqueous solutions are described in this report. Four pairs of one‐electron transfer reduction and oxidation cyclic voltammetry is obtained in aqueous solution containing 30% CH3CN and 2% (C3H5)4NOH. It is reported in this paper that the Ceo modified electrode also catalyzes the electrochemical reduction of dissolved oxygen in 40% DMF and 2% (C2H5)4NOH aqueous solution and this might open a new field for the potential applications of C60 in electrochemistry and electroanalytical chemistry.
Study on polymerization and structure of polydiphenylamine
Authors: Jin Wen , Song Fa‐Yi , Dong Shao‐Jun
Published: September 2010

The electrochemical oxidation of diphenylamine in acetonitrile produces an adherent uniform polymer film which exhibits mutiple colour variation(yellow‐green‐blue) in a wide range of potential scan. The polymerization mechanism and the structure of the polymer were studied by cyclic voltammetry, FT‐IR and in situ ESR. The results indicate that the electrochemical polymerization of diphenylamine belongs to a cationic radical polymerization process. During electrolysis, only oligomers were initialy produced, then polymer film was formed on the electrode surface. The electropolymerization performs via the 4,4′ C‐C phenyl‐phenyl coupling mechanism.
The synthesis and phase transition of 4′‐methylphenyl 4″‐[(4‐alkoxy‐2,3,5,6‐tetrafluorophenyl)ethynyl]benzoates
Authors: Xu Yu‐Lian , Wang Wei‐Li , Chen Qi , Wen Jian‐Xun
Published: September 2010

A homologous aeries of 4′‐methylphenyl 4″‐[(4‐alkoxy‐2,3,5,6‐tetrafluorophenyl)ethynyl]‐benzoates have been synthesized. Polarizing microscopic textural observation shows that such compounds exhibit enantiotropic nematic phase.
Synthesis of 1,4,6‐tri‐O‐benzyl myo‐inositol—A key intermediate to myo‐inositol‐1,2,5‐O‐trisphosphate
Authors: Yuan Cheng‐Ye , Zhai Hai‐Xiao , Weng Guan‐Hong
Published: September 2010

A new synthetic approach to 1,4,6‐tri‐O‐benzyl myo‐inositol was described on the basis of the regioselective benzylation of 1,2‐O‐iaopropylidene‐4,6‐di‐O‐benzyl myo‐inositol, subsequent acid hydrolysis, phosphorylation with tetrabenazylpyrophosphate and appropriate deprotection.
Temperature effect on the ease of aggregation
Authors: Zhang Jin‐Tao , Nie Jin , Sun Si‐Xun , Ji Guo‐Zhen , Jiang Xi‐Kui
Published: September 2010

The effect of temperature on the critical aggregate concentration (CAgC) has been investigated for the first time, by measurement of the hydrolytic rate constants of p‐nitrophenyl dodecanoate (C12) and hexadecanoate (C16) at different temperatures in the 30:70 V/V (θ·=0.30) and 40:60 V/V (θ = 0.40) dioxane (DX)‐H2O systems. The CAgC values of C12 and C16 increase with the increase of the temperature, i.e., high temperatures disfavor aggregation. Activation energies for the hydrolysis of C12 in the monomeric and aggregated concentration domains have also been discussed.
The further crystallographic refinement of trichosanthin at 2.7 A resolution and the comparison among the three molecular structures in two crystal forms
Authors: Zhang Lei , Xia Zong‐Xiang , Wu Shen , Dong Yi‐Cheng
Published: September 2010

The three‐dimensional structure of trichosanthin at 2.7Å resolution has been improved further, by refitting one of the C‐terminal tails, adjusting 16 residues in the molecular surface regions, discarding some water molecules with high B values, and adjusting weights during the further refinement. The R‐factor has been reduced to 18.5% and the r.m.s deviations from ideal geometry are also improved. The structures of the two molecules in the monoclinic asymmetric unit and the only molecule in the orthorhombic asymmetric unit are compared with one another. The main‐chain structures for most of the residues in the three molecules are substantially the same. However, the courses of the three C‐terminal tails are completely different, and the intermolecular interactions resulting from the particular packing of the molecules in the crystals account for the differences. The strand βe‐2 and the preceding β‐turn in small domain show large r.m.s. deviations among the three molecules and they are also involved in intermolecular interactions.
Synthesis and magnetic properties of binuclear cobalt(II), nickel(II) and copper (II) complexes bridged by oxamidate group
Authors: Jiang Zong‐Hui , Deng Chao‐Li , Liao Dai‐Zheng , Yan Shi‐Ping , Wang Geng‐Lin
Published: September 2010

Four binuclear Co(II), Ni(II) and Cu(II) complexes bridged by oxamidate (oxd) group have been synthesized, namely Co2(byp)2(oxd)(C104)2 (1), Co2(Me2bpy)2(oxd)(ClO4)2·H2O (2), Ni2(bpy)2(oxd)(ClO4)2·2H2O (3) and Cu2(Me2bpy)2(oxd)(NO3)2 (4). (bpy=2,2′‐bipyridyl, Me2‐bpy=4,4′‐dimethylbipyridyl, oxd=oxamidate) The complexes are characterized by IR, UV spectra, EPR and variable‐temperature magnetic susceptibility (4–300 K). The susceptibility data for complexes 1 and 3 were least‐squares fit to the susceptibility equation derived from the spin Hamiltonian Ȟ=‐2J · Š1·2. The exchange integral, J, was found to be equal to −3.62 cm−1 in 1 and −1.82 cm−1 in 3. This indicates a weak antiferromagnetic spin exchange interaction between the metal ions.
Synthesis, spectroscopic properties, and tautomerism of mono‐meso‐substituted octamethylporphyrins
Authors: Li Ming , Yao Yi‐Ming , Zou Jian‐Zhong , Xu Zheng , You Xiao‐Zeng
Published: September 2010

The synthesis spectroscopic properties and tautomerism of four novel mono‐mesosubstituted(R)‐octamethylporphyrins (R=o‐hydroxybenzyl, p‐aminobenzyl, 4‐pyridinyl, and ferrocenyl) were investigated. It was found that the porphyrins2, 3 could be directly prepared in good yields via the coupling reaction of salicylaldehyde and p‐aminobenzyl aldehyde with octamethyl‐1′,8′‐dideoxy‐ac‐biladiene dihydrobromide, respectively. The free energy of activation (ΔG≠) of the tautomerism of the porphyrins was calculated and interpreted in terms of electronic and steric nature. In contrast with 2‐substituted‐5,10,15,20‐tetraphenylporphyrins, the substituents in meso position do not change the relative amount of two tautomers a and b.
Syntheses, properties and structures of copper and nickel complexes of 6,7‐dihydro‐5H‐1,4‐dithiepin‐2,3‐dithiolate
Authors: Yao Tian‐Ming , You Xiao‐Zeng , Yang Qing‐Chuan
Published: September 2010

The reaction of CuCl2·2H2O or NiCl2·6H2O with K2(C5H6S4) [potassium salt of 6,7‐dihydro‐5H‐1,4‐dithiepin‐2,3‐dithiolate] under nitrogen atmosphere resulted in the isolation of [Cu(C5H6S4)2]− or [Ni(C5H6S4)2]− as the tetrabutylammonium salt. Both complexes show characteristic IR and UV −Vis absorptions of transition metal dithiolenes. Cyclic voltammograms contain two waves indicating a two step electrochemical procedure [M(C5H6S4)2]0 = [M(C5H6S4)2]1‐= [M(C5H6S4)2]2‐ Single crystal structure study has been carried out on the nickel complex. Crystal of [Bu4N][Ni(C5H6S4)2] belongs to monoclinic space group P21/c with a=17.576(5), b=10.883(2), c=17.773(4) A, β=91.07(2)°, Z=4, and ρ(calcd.)=1.348 g/cm3. Final result is R=0.059 for 2959 reflections. The NiS4 core exhibits square planar coordination with average Ni—S bond length of 2.134(5) Å. There are not anion pairs in crystal. The anions stack along a and c axes while the cations intercalate in them. The nearest S—S contact is 4.429 Å. The solid powder ESR spectrum of the nickel complex shows three broadening signals at g1 =2.097, g2=2.042, g3=2.022. Magnetic susceptibility data for [Bu4N][Ni(C5H6S4)2] reveal enhanced anti‐ferromagnetic interaction.
An open chain product in the reaction of benzil with thiocarbohydrazide
Authors: Deng Shui‐Quan , Huang Xiao‐Yin , Zhuang Hong‐Hui , Huang Jin‐Ling , Lin Zhen‐Guang
Published: September 2010

An open chain compound was obtained by reaction of benzil with thiocarbohydrazide in acidic condition. Its derivative, namely, benzil bis‐(5‐isopropylidene‐3‐thiocarbohydrazone) has been structurally characterized by X‐ray single crystal diffraction method. Crystallographic data. C22H26N8S2, Mr=466.62, monoclinic, space group C2/c,a=12.215(3), b=11.473(2), c=17.032 (3)Å, β=98.96(2)°, V=2357.7(9)Å3, Z=4, Dc=1.32 g/cm3, F(000)=1040, μ(Mo Kα)=2.43 cm−1. Final R=0.050, Rw=0.061 for 1103 unique and observed reflections with I ≥ 3σ(I). The effect of the structures on the formation of the open‐chain intermediates during the cyclization of (2:2) Schiff base macrocyclic compound has been discussed and a possible mechanism for the ring closure has been suggested.
Fluorescence study on the coaggregating tendencies of the cholesterols—the culprits of arteriosclerosis
Authors: Zhang Jin‐Tao , Ji Guo‐Zhen , Jiang Xi‐Kui
Published: September 2010

The coaggregating tendencies of the culprits of arteriosclerosis, the cholesteryl esters (CE‐n's), have been investigated in the 40:60 V/V (Φ = 0.40) dioxane (DX)‐H2O system, by using decyl pyrenyl ketone (Py‐11) as the fluorescence probe. The fluorescence intensity of Py‐11 decreases when coaggregation occurs between CE‐n and Py‐11, because of the low polarity of the microenviroment of the coaggregates. The order of the coaggregating tendencies obtained from the fluorescence data is in full agreement with that from the kinetic method, i.e., CE‐ol, CE‐ln > CE‐12 > CE‐8 > CE‐18 > CE‐0.
Synthesis of Imidazothiazole–Chalcone Derivatives as Anticancer and Apoptosis Inducing Agents
Authors: Kamal Ahmed , Dastagiri D. , Ramaiah M. Janaki , Reddy J. Surendranadha , Bharathi E. Vijaya , Srinivas Chatla , Pushpavalli S. N. C. V. L. , Pal Dhananjaya , Pal‐Bhadra Manika
Published: September 2010

A new class of imidazo[2,1‐b]thiazole chalcone derivatives were synthesized and evaluated for their anticancer activity. These chalcone derivatives show promising activity, with log GI50 values ranging from −7.51 to −4.00. The detailed biological aspects of these derivatives toward the MCF‐7 cell line were studied. Interestingly, these chalcone derivatives induced G0/G1‐phase cell‐cycle arrest, down‐regulation of G1‐phase cell‐cycle regulatory proteins such as cyclin D1 and cyclin E1, and up‐regulation of CDK4. Moreover, these compounds elicit the characteristic features of apoptosis such as enhancement in the levels of p53, p21, and p27, suppression of NF‐κB, and up‐regulation of caspase‐9. One of these chalcone derivatives, 3 d, is potentially well suited for detailed biological studies, either alone or in combination with existing therapies.
Applying weak equivalence of categories between partial map and pointed set against changing the condition of 2‐arms bandit problem
Authors: Niizato Takayuki , Gunji Yukio‐Pegio
Published: September 2010

The main interest of the organizational learning is that the agent balances between exploring and exploiting. When the agent decides the answer in finite time, it gives rise to the problem that is trade‐off between exploring and exploiting. This problem never arises in the given enough time. The agent must decide answer from his imperfect information, when the time is given finite for the task. 2‐arms bandit problem is often taken into consideration in this problem. In previous article, we proposed the model for weak identity that is dynamically changing the hierarchy of his knowledge. Recently, the method of the heuristic model is attracted to approach this problem. In this article, we proposed different approaches for 2‐arms bandit problem, and the model we proposed can adapt to the environment when the condition of the problem is changed and shows another approach to the organizational learning. © 2010 Wiley Periodicals, Inc. Complexity 16: 10‐21, 2011
How corporate social responsibility information influences stakeholders' intentions
Authors: Alniacik Umit , Alniacik Esra , Genc Nurullah
Published: September 2010

The study shows how positive and negative information on corporate social and environmental responsibility influences purchase, employment, and investment intentions of various stakeholders. We manipulated the information on corporate social responsibility (CSR) activities of a hypothetical firm in a between‐subjects experimental design. The design had two treatments. In the ‘positive CSR’ treatment, the company's social and environmental performance was described in a positive perspective (depicting a strong social performance), whereas in the ‘negative CSR’ treatment it was described in a negative perspective (depicting a weak social performance). In both treatments, information about other key characteristics of the focal company were kept constant. Respondents' intentions to purchase products from, seek employment with, and invest in the company were evaluated by multi‐item scales. The results demonstrate that positive CSR information about a firm enhances consumers' intentions to purchase products from, potential employees' intentions to seek employment with, and potential investors' intentions to invest in the company. Theoretical and managerial implications of the findings are discussed. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
A linear, ultra wideband, low‐power, 2.1–5 GHz, VCO
Authors: Tsitouras Athanasios , Plessas Fotis , Kalivas Grigorios
Published: September 2010

A linear, Ultra Wideband, low‐power VCO, suitable for UWB‐FM applications is proposed, forming the main part of a UWB‐FM transmitter. The VCO is designed in TSMC 90thinspacenm digital CMOS process and includes a Source‐Coupled Multivibrator, used as current‐controlled oscillator (CCO) which generates output frequencies between 2.1 and 5 GHz and a voltage‐to‐current (V‐to‐I) converter which translates the VCO input voltage modulation signal to current. Two single‐ended inverter buffers are employed to drive either a differential or a single‐ended UWB antenna. The presented VCO is designed for 1 V power supply and exhibits a linear tuning range of 2.1–5 GHz, a differential output power of −7.83 dBm±0.78 dB and low power consumption of 8.26 mW, including the output buffers, at the maximum oscillation frequency. It is optimized for a very high ratio of tuning range (81.69%) over power consumption equal to 9.95 dB. The desired frequency band of 3.1–5 GHz for UWB‐FM applications is covered for the entire industrial temperature range (−40 to 125∘C). Copyright © 2010 John Wiley & Sons, Ltd.
Historical perspective on mitochondrial medicine
Authors: DiMauro Salvatore , Garone Caterina
Published: September 2010

In this review, we trace the origins and follow the development of mitochondrial medicine from the premolecular era (1962–1988) based on clinical clues, muscle morphology, and biochemistry into the molecular era that started in 1988 and is still advancing at a brisk pace. We have tried to stress conceptual advances, such as endosymbiosis, uniparental inheritance, intergenomic signaling and its defects, and mitochondrial dynamics. We hope that this historical review also provides an update on mitochondrial medicine, although we fully realize that the speed of progress in this area makes any such endeavor akin to writing on water. © 2010 Wiley‐Liss, Inc. Dev Disabil Res Rev 2010;16:106–113.