bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic field effects on photoreduction reaction of 2‐methyl‐1,4‐naphthoquinone in brij 35 micellar solution with additional radical
Authors: Chen Jia‐Fu , Xue Xuan 
Published: September 2010

AbstractA study was made of magnetic field effects (MFEs) on the photoreduction reaction of 2‐methyl‐1, 4‐naphthoquinone (MNQ) in Brij 35 micellar solution containing 4‐lauroylamino‐TEMPO (2,2,6,6‐tetramethylpiperidine‐l‐oxyl) radical (L‐R) under magnetic fields below 1.75 T by a nanosecond laser flash photolysis technique. The triplet MNQ mainly underwent the hydrogen abstraction from Brij 35 molecule to give a radical pair. The escaped radical yield increased with magnetic fields from 0 to 0.62 T and then saturated from 0.62 to 1.75 T. MFEs for both system can be explained by the relaxation mechanism. However, it was supposed that additional radical, L‐R affected the MFEs mainly through enhancing the spin‐spin interactions of radical pairs. The effect of the micelle size on MFEs of the studying system was also discussed.
XPS characterization of carbon nanotube supported CoMo hydrodesulfurization catalysts
Authors: Shang Hong‐Yan , Liu Chen‐Guang , Zhao Rui‐Yu , Wu Ming‐Bo , Wei Fei 
Published: September 2010

AbstractIn this paper, the effect of catalytic support and sulfiding method on the chemical state of supported Co‐MO catalysts is studied by XPS. After sulfidation with in‐situ method, the majority of molybdenum in CNT supported CoMo catalyst is transferred to a species with a formal chemical state Mo(IV) in MoS2 phase, and the rest to Mo(V) which consists of Mo coordinated both to O and S, such as MoO2S22‐‐ and MoO3S2‐−. In case of CoMo/γ‐Al2O3 catalyst sulfided with in‐situ method, a fraction of molybdenum is transferred to formal state Moo in the form of MoS2, but there is still a mount of unreduced Mo(VI) phase which is difficult to be sulfided. In CoMo/CNT catalytic system sulfided with ex‐situ method, Mo(IV) in the form of MoS2 is detected along with a portion of unreduced Mo(VI) phase, suggesting that not all the Mo phases are reduced and sulfided by ex‐situ method. As for CoMo/γ‐Al2O3, a portion of molybdenum is sulfided to intermediate reduced state Mo(V) which consists of Mo coordinated both to O and S. such as MoO2S2–2 and MoO3S2–, in addition, there is still a fraction of unreduced Mo(VI) phase. XPS analyses results suggest that CNT support facilitates the reduction and sulfidation of active species to a large extent, and that alumina support strongly interacts with active species, hereby producing a fraction of phase which resists complete sulfiding. Catalytic measurements of catalysts in the HDS of dibenzothiophene (DBT) show that CoMo/CNT catalysts are of higher HDS activity and selectivity than CoMo/γ‐A2O3 catalyst, which is in good relation with the sulfiding behavior of the corresponding catalyst.
Solution‐reaction calorimetric study of coordination compounds of rare earth perchlorates with alanine and imidazole
Authors: Zhao Yan‐Ru , Hou An‐Xin , Dong Jia‐Xin , Zhao Shun‐Sheng , Liu Yi , Qu Song‐Sheng 
Published: September 2010

AbstractTwo coordination compounds of rare earth perchlorates with alanine and imidazole, [RE(Ala)n(Im)(H2O)]‐(ClO4)3(s) (RE=La,n=3; RE=Nd,n=2), have been prepared and characterized. The standard molar enthalpies of reaction for the following two reactions, LaCl3*7H2O(s) + 3Ala(s)+Im(s)+3NaClO4(s)=[La(Ala)3(Im)(H2O)]‐(Cl04)3(S) f 3NaCI(s) + 6H2O(1) (1) and NdCl36H2O(s) + 2Ala(s) + Im(s) + 3NaClO4(s) = [Nd(Ala)2(Im)(H2O)]‐(ClO4)3(s)+3NaCl(s)+5H2O(1) (2), were determined by solution‐reaction calorimetry, at T=298.15 K, as 36.168±0.642 kJ.mol−1and 48.590±0.934 kJ.mol−1respectively. From the results and other auxiliary quantities, the standard molar enthalpies of formation of [La(Ala)3(Im)(H2O)](Cl04)3(s) and [Nd(Ala)2(Im)(H2O)] (Cl04)3(s) were derived, ΔfH{[La(Ala)3(Im)(H2O)](ClO4)3, s) =(−2984.8 ± 1.0) kJ.mol‐land ΔfH{[Nd(Ala)2(Im)(H2O)]‐(ClO4)3,s) =(−2387.8±0.8) kJ.mol−1, respectively.
Synthesis of lanthanide coordination polymers with benzophenone‐4,4′‐dicarboxylate: Effect of lanthanide contraction on structures
Authors: Wang Yi‐Bo , Jin Lin‐Pei 
Published: September 2010

AbstractFour lanthanide coordination polymers with benzophenone‐4,4′‐dicarboxylic acid (H2bpndc) and 1,10‐phenanthroline (phen), [Ln2(bpndc)3(phen)] (Ln=La (1), Pr (2) and Tb (3)), [Yb(bpndc)15(phen)].05H2O (4) were obtained through solvothermal synthesis. The crystallographic data show that 1, 2, and 3 are isostructural, the Ln(III) ions in 1, 2 and 3 are all eight‐ and ten‐coordinated, respectively, and thus the Ln(III) ions are connected by bpndc ligands, resulting in an interpenetrating 3D structure. While in 4, the Yb(III) ions are eight‐coordinated and connected by bpndc ligands into a 3D structure with 1D rhombic channels, which result from the effect of lanthanide contraction from La(III) to Yb(III) ions, and the bpndc ligands in 1, 2, 3, and 4 display three types of coordination modes.
Synthesis and thermal decomposition mechanism of rare earth (RE=La, Y, Gd) salicylates
Authors: Li Liang‐Chao , Zhou Xiang‐Chun , Zheng Ren‐Wei 
Published: September 2010

AbstractThe rare earth (RE=La, Y, Gd) salicylates were synthesized by the rheological phase reaction method. The complexes were characterized by elemental analysis, infrared spectra (IR), X‐ray powder diffraction (XRD) and thermal gravity analysis (TG). They can be represented by general formula RE(HSal)3 (RE=La, Y, Gd; HSal= C6H4(OH)COO). The crystals of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth salicylates was studied by using TG, DTA, IR and gas chromatography‐mass spectrometry (GC‐MS). The thermal decomposition of the rare earth salicylates in nitrogen gas proceeded in three stages: firstly, they were decomposed to form RE2(Sal)3(Sal=C6H4OCOO) and salicylic acid; then, RE2(Sal)3 were decomposed further to form RE2O(CO3)2 and some organic compounds; finally, RE2O(CO3)2 were decomposed to form rare earth metal oxides (RE2O3) and carbon dioxide. The organic compounds obtained from the second step of the reaction are mainly dibenzofuran, xanthenone, 6H‐benzo[c]chromen‐6‐one, 6‐phenyl‐6H‐benzo[c]chromene, and 1,3‐diphenyl‐1, 3‐dihydro‐2‐benzofuran.
Synthesis, structure and biological activities of novel triazole compounds containing 4,6‐dimethyl‐pyrimidin‐2‐ylthio group
Authors: Xu Liang‐Zhong , Jian Fang‐Fang , Shi Jian‐Gang , Li Lin 
Published: September 2010

AbstractFour compounds were prepared by reacting 4,6‐dimethyl‐2‐mercaptopyrimidine with a‐bromo‐a‐( 1,2,4‐mazol‐l‐yl)substituted acetylbenzene. Their structures were identified by means of elemental analysis, IR, and 1H NMR spectra. The single crystal structure of 2–[1–(1,2,4triazol‐1‐yl)‐l‐p‐methoxyphenylcarbonylmethylmethylthio]‐4,6‐dimethyl‐pyrimidine was also determined. It crystallizes in monoclinic system, space group P21/c, a=0.8016(2) nm, b=1.2462(3) nm, c= 1.7824(4) nm, β=99.89(3)°, Z=4, V=1.7540(7) nm3, Dc= 1.346 g/cm3, μ=0.205 m‐1, F(000)=744, final R1 =0.0452. There is obviously potentially weak CH…︁N intermolecular interaction between the molecules in the crystal lattice, which stabilizes the crystal structure. The result of the biological test showed that the four compounds all have some fungicidal and plant growth regulating activities.
Study on PEG‐(NH4)2SO4 aqueous two‐phase system and distribution behavior of drugs
Authors: Li Lei , He Chi‐Yang , Li She‐Hong , Liu Feng , Su Shun , Kong Xiang‐Xu , Li Na , Li Ke‐An 
Published: September 2010

AbstractThe distribution behavior of chlorpromazine hydrochloride (CPZ), procaine hydrochloride (PCN) and procaine amide hydrochloride (PCNA) in polyethylene glycol (PEG800 or PEG1500)‐(NH4SO4 aqueous two‐phase systems has been investigated. The result shows that the PEG‐(NH4SO4 aqueous two‐phase system has potential extraction capability in small molecular drug separation. In PEG800–(NH4)2SO4 system, the extraction efficiencies (E) of CPZ, PCN and PCNA amount to 92.8%, 74.5% and 74.4%, respectively, with the distribution coefficients (KD) being 25.7, 5.9 and 5.8, correspondingly. In PEG1500–(NH4)2SO4 system, the extraction efficiencies (E) of CPZ, PCN and PCNA are 93.7%, 71.3% and 63.24, respectively, with distribution coefficients (KD) of 39.6, 6.6 and 5.0, correspondingly. Based on the study on ultraviolet and fluorescence spectra and also distribution behavior of the drugs in PEG‐(NH4)SO4 aqueous two‐phase system, extraction mechanism was further proposed that both hydrogen bond and hydrophobic interaction are involved in extraction.
Near‐infrared hydrophobic probes as molecular light switch for cmc determination of triton X‐100 solution
Authors: Zhu Chang‐Qing , Zheng Hong , Li Dong‐Hui , Li Shun‐Hua , Xu Jin‐Gou 
Published: September 2010

AbstractThe fluorescence behavior of two near‐infrared (NIR) chromophores with linear alkyl chains of different lengths, 2–[4′chloro‐7′(3″ethyl–2″benzothiazolinylidene)‐3′,5′‐(1‴,3‴‐propanediyl)‐1′,3′,5′‐heptantriene‐1′‐yl]‐3‐ethylbenzothiazolium iodide (Robe I) and 2–[4′chloro‐7′(3″hexadecyl‐2″benzothiazolinylidene)‐3′,5′‐(1‴,3‴‐propanediyl)‐1′,3′,5′‐heptantriene‐1′‐yl]‐3‐ethylbenzothiazolium iodide (Probe II), in aqueous solution containing different concentrations of surfactants was studied. The fluorescence of the probe with a short chain (probe I) was completely quenched in water and aqueous solution containing a low concentration (below the critical micelle concentration, CMC) of surfactant Triton X‐100. However, the fluorescence reappeared and reached maximum rapidly once the concentration of the surfactant approached the CMC. The probe with a long chain (probe II) displayed a similar fluorescence behavior but more dramatically fluorescent recovery in Triton X‐100 system, which gave a direct indication for the micelle forming process and provided a simple method for the determination of the critical micelle concentration of the surfactant. The CMC values determined by this method were in good agreement with those obtained by other techniques. The fluorescence behavior of the two probes in other surfactant systems was also investigated.
Chiral borated esters in asymmetric synthesis: 1. the first asymmetric reaction catalyzed by chiral spiroborated esters with an O3BN framework
Authors: Liu De‐Jun , Shan Zi‐Xing , Qin Jin‐Gui 
Published: September 2010

AbstractThe first asymmetric reaction catalyzed by chiral spiroborated esters with an O3BN framework was reported. In the presence of 0.1 equivalent of (R,S)‐1 or (S,S)‐1, acetophenone was reduced by 0.6 equivalent of borne in THF at 0–5 °C for 2 h to give (R)‐1‐phenylethanol of up to 76% ee and 73% isolated yield. Influence of reaction conditions on the stereoselectivity of the reduction was investigated and a possible catalytic mechanism of the chiral spiroborated esters toward the reduction was also suggested.
Gal3 catalyzed tetrahydropyranylation of alcohols and phenols
Authors: Sun Pei‐Pei , Hu Zhi‐Xin 
Published: September 2010

AbstractIn dichloromethane, the nucleophilic addition of alcohols or phenols to 3,4‐dihydro‐2H‐pyran (DHP) was catalyzed effectively by gallium triiodide which was generated in situ by the reaction of gallium metal and iodine to give the corresponding tetrahydropyranyl acetals in good to excellent yields.
Synthesis of the active stilbenoids by photooxidation reaction of trans‐ϵ‐viniferin
Authors: Yao Chun‐Suo , Lin Mao , Wang Ying‐Hong 
Published: September 2010

AbstractTwo new stilbenoids, cis‐ϵ‐viniferin (3) and 2b, 14b‐dehydro‐bisresveratrol (4) were synthesized by photooxidation reaction of trans‐ϵ‐viniferin (2) prepared from tram‐resveratrol (1). Pentamethoxyl trans‐ϵ‐viniferin (5) and pentamethoxyl cis‐ϵ‐viniferin (6) were also obtained by methylation of trans‐ϵ‐viniferin (2) with (MeO)2SO2. Their structures were elucidated on the basis of spectral evidence. Compounds 3 and 4 showed potent inhibition of TNF‐α at concentrations of 10−‐5 mol.L−1 with inhibitory ratios of 51.43% and 36.64%. respectively.
Electrocatalytic oxidation of vitamin B6 by 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl
Authors: Li Yan , Wen Xiao‐Lin , Liu Zhong‐Li 
Published: September 2010

AbstractThe electrochemistry of pyridoxine (vitamin B6, VB6) was studied by cyclic voltammetry at a glassy carbon electrode. The electrochemical response of VB6 could be significantly enhanced by using 4‐hydroxy‐2,2,6,6‐tetra‐methylpiperidine‐N‐oxyl (HO‐TEMPO) as a mediator via an electrocatalytic EC' mechanism with the oxoammonium ion of HO‐TEMPO as the active oxidant. The catalytic rate constant was determined to be 5.4×103 (mol*L−1)−1*s−1 by using chronomperometq.
An efficient synthesis of highly optically active 4‐substituted‐2(5H)‐furanones from chiral 3‐bromo‐2(5H)‐furanone
Authors: Fan Xue‐E , Huang Min , Huang Hui , Chen Qing‐Hua 
Published: September 2010

AbstractHighly optically active 4‐substituted‐2(5H)‐furanones 6a‐6j were obtained in good yields with de⩾98% by the tandem Michael addition/elimination reaction of chiral 3‐bromo‐2(5H)‐furanone (4a), which was conveniently prepared starting from 2‐furaldehyde under mild conditions. The products were identified on the basis of their satisfactory elemental analysis and spectroscopic data of IR, W, 1H NMR, 13C NMR and mass spectra. The stereochemistry and absolute configuration of this type of compounds were established by the X‐ray crystallographic study. The reaction provided a short and efficient synthesis of the interesting highly optically active 4‐substituted‐2(5H)‐furanones containing an active pyrimidine and a purine base group.
Synthesis of novel carbosilane dendrimers based on pentaerythritol
Authors: Tang Xin‐De , Zhang Qi‐Zhen , Fan Xing‐He , Zhou Qi‐Feng 
Published: September 2010

AbstractNovel pentaerythritol‐based carbosilane dendrimers centered at carbon have been synthesised. Starting from tetraallyl ether based upon pentaerythrtol as the core molecule, a succession of alternate Pt‐catalyzed hydrosilylation of allyl groups with HSiC13 and allylations of Sicl groups thus introduced with CH2=CHCH2MgBr in THF provided a divergent synthesis of three generations of carbosilane dendrimers in which the Si atoms are linked by CH2CH2CH2 groups. The reaction conditions for hydrosilylation must be well controlled. After purification by chromatography on silica gel pure products for each generation were obtained. The IR, 1H and 13C NMR spectra and elemental analysis data are consistent with the proposed structures. The molecular weights of the resulting carbosilne dendrimers have been determined by vapor pressure osmometry.
Amide‐based fluorescent macrocyclic anion receptors
Authors: Zeng Zhen‐Ya , Xu Kuo‐Xi , He Yong‐Bing , Liu Shun‐Mng , Wu Jin‐Long , Wei Lan‐Hua , Meng Ling‐Zhi 
Published: September 2010

AbstractTwo fluorescent anion receptors (1 and 2) based on amide macrocycle were synthesized and corresponding fluorescence quenching induced by anion complexation was observed in different degree. Receptors form 1:1 complexes with anions by hydrogen bonding interactions. Receptor 1 bound anions in the order of F‐>Cl‐ > H2PO4−‐ CH3COO− > >Br−, I− and receptor 2 showed high selectivity to F− over other anions.
Ab initio calculation of intermolecular dispersion energy and induction energy of nitramide dimer
Authors: Song Hua‐Jie , Xiao He‐Ming , Dong Hai‐Shan , Huang Yi‐Gang , Long Xin‐Ping , Tang Yei‐Peng 
Published: September 2010

AbstractThe dispersion energies, induction energies and their exchange counterparts (exchange‐dispersion and exchange‐induction energies) between two interacting nitramide molecules at several separations are derived based upon symmetry‐adapted perturbation theory (SAPT). The results show that (1) the effect of intramonomer electron correlation on dispersion energies and induction energies for nitramide dimer system is remarkable especially in the region near the van der Waals minimum distance (0.42 nm). (2) At smaller separations the dispersion energies and the induction energies are largely quenched by their exchange counterparts, and this case in induction interaction is much more remarkable than in dispersion interaction. (3) Since at shorter distances there exists the strong short‐range interaction due to electron transfer which quickly decays and even disappears at larger separations, the two different R‐dependency formulae of induction energies were found: one is cu. R−12.7 at short distances, and the other cu R−7.0 at large separations. The latter R‐dependency is similar to that (ca. R−7.2) of dispersion. (4) In the case of strong polar interaction existing in nitramide dimer, the “true” induction correlation terms of higher order than 1Eind(22) may be important.
Direct electrochemistry of cytochrome c on EDTA‐ZrO2 organic‐inorganic hybrid film modified electrodes
Authors: Xu Jing‐Juan , Peng Ying , Liu Shou‐Qing , Chen Hong‐Yuan 
Published: September 2010

AbstractA composite film of ethylenediamine tetraacetic acid (EDTA)‐ZrO2 organic‐inorganic hybrid was prepared based on the chelation between Zr(IV) and EDTA. The direct electrochemical behavior of cytochrome c (cyt. c) at the hybrid film modified glassy carbon electrodes was investigated. The immobilized EDTA can promote the redox of heme in horse heart cyt. c which gives rise to a pair of reversible redox peaks with a formal potential of 40 mV (vs. SCE). The peak current increased linearly with the increase of cyt. c concentration in the range of 1.6 × 10−6—8.0 × 10−5 mol·L−1 with the correlation coefficient of 0.996. Further investigation shows that metal ions can impede the electron transfer of cyt. c. The impediment capability of metal ions depends on their coordination capability with EDTA and their valence number.
Novel role of carbon dioxide as a selective agent in palladium‐catalyzed cyclotrimerization of alkynes
Authors: Li Jin‐Heng , Xie Ye‐Xiang 
Published: September 2010

AbstractCarbon dioxide was found as a selective agent to promote the palladium‐catalyzed cyclotrimerization of alkynes in water. Both aryl and alkylacetylenes afforded the corresponding cyclotrimerization products regioselectively in high yields using PdCl2, CuCl2, and CO2 as the catalytic system. However, tert‐butylacetylene bearing a bulky group gave a dimerization product. Mechanism of this reaction was also discussed.
The concentration of hydrogen peroxide generated during aggregation of α‐synuclein in vitro is lower than 5 nmol/L
Authors: Ji Li‐Na , Li Hong‐Tao , Luo Xiao‐Ying , Zhang Feng , Hu Hong‐Yu , Hu Jun 
Published: September 2010

AbstractUsing a fluorometric method with a detection limit of 5 nmol/L. here it is reported that albeit positive results were got from bovine serum albumin (BSA) and chicken ovalbumin (OVA) as published in literature, no detectable amount of hydrogen peroxide (H2O2) was generated during α‐synuclein (α‐Syn) aggregation in vitro even in the presence of transition metal ions Cu(II) or Fe(III). The results suggest that the concentration of H2O2 generated during aggregation of α‐Syn in vitro be lower than 5 nmol/L beyond the detection limit of the adopted method and it is far too poor to be responsible for the cytotoxicity of α‐Syn aggregates, thus allowing people to extensively elucidate the mechanism underlying neurotoxicities of the aggregates formed by some amyloidogenic proteins.
Microcalorimetric studies on influence of Sm3+, Dy3+ on growth and sporulation of Bacillus thuringiensis
Authors: Zhao Ru‐Ming , Liu Yi , Yang Chang‐Ving , Xie Zhi‐Xiong , Shen Ping , Qu Song‐Sheng 
Published: September 2010

AbstractBy using an LKB‐2277 Bioactivity Monitor and cycle‐flow method, the thermogenic curves of aerobic growth for Bacillus thuringiensis cry II strain at 28 °C have been obtained. The metabolic thermogenic curves of Bt cry II contain two distinct parts: the first part reflects the changes of bacterial growth phase and the second part corresponds to sporulation phase. From these thermogenic curves in the absence or presence of Sm3+, Dy3+ ions, the thermokinetic parameters such as the growth rate constants k, the interval time τI, the maximum power PMAX1 and heat‐output QLOG for log phase, the maximum power PMAX2 and heat‐output QSTAT for stationary phase, the heat‐output QSPOR for sporulation phase and total heat effects QT were calculated. Sm3+ and Dy3+ ions have promoting action on the growth of Bt cry II in their lower concentration range, on the other hand, they have inhibitory action on the sporulation of Bt in their higher concentration range. It has also been found that the effects of Sm3+ and Dy3+ ions on Br firing the sporulation phase were far greater than those during the bacterial growth phase. It was concluded that the application of Bt for controlling insecticide could not be affected by the presence of the rare‐earth elements in the environmental ecosystem.
Atmospheric and Surface Water Pollution Interpretation in the Gdańsk Beltway Impact Range by the Use of Multivariate Analysis
Authors: Dubiella‐Jackowska Aleksandra , Astel Aleksander , Polkowska Żaneta , Staszek Wojciech , Kudłak Błażej , Namieśnik Jacek 
Published: September 2010

AbstractThe present study deals with the application of the hierarchical cluster analysis and non‐parametric tests in order to interpret the Gdańsk Beltway impact range. The data set represents concentration values for major inorganic ions (Na+, NH, K+, Mg2+, Ca2+, F−, Cl−, NO, and SO) as well as electrolytic conductivity and pH measured in various water samples [precipitation, throughfall water, road runoff, and surface water (drainage ditches, surface water reservoirs, and spring water)] collected in the vicinity of the beltway. Several similarity groups were discovered both in the objects and in the variables modes according to the water sample. In the majority of cases clear anthropogenic (fertilizers usage and transport, road salting in winter) and semi‐natural (sea salt aerosols, erosion of construction materials) impacts were discovered. Spatial variation was discovered for road runoff samples and samples collected from surface water reservoirs and springs. Surprisingly no clear seasonal variability was discovered for precipitation chemistry, while some evidences for existing of summer and winter specific chemical profile was discovered for road runoff samples. In general, limited range of the Gdańsk Beltway impact was proven.
Malachite Green Adsorption by a Residue‐based Microwave‐activated Adsorbent
Authors: Franca Adriana S. , Oliveira Leandro S. , Nunes Anne A. 
Published: September 2010

AbstractAn adsorbent obtained by microwave activation of defective coffee press cake was evaluated for malachite green (MG) removal from aqueous solutions. Batch adsorption tests were performed and the effects of particle size, contact time, adsorbent dosage, initial solution pH, and initial dye concentration on MG removal from aqueous solutions were investigated. Adsorption kinetics was determined by fitting pseudo‐first‐ and second‐order kinetic models to the experimental data, with the second‐order model providing the best description of MG adsorption onto the prepared adsorbent. The experimental adsorption equilibrium data were better described by the Langmuir model in comparison to Freundlich. The results presented in this study show that the produced adsorbent presents great potential as an inexpensive and easily available alternative for the removal of cationic dyes in wastewater treatments.