2007 Volume 18 Issue 2

Free radical mediated bromization of methylenecyclopropanes:Preparation of 2,4-dibromobutenes without transition metal
Lei Yu , Bo Chen , Xian Huang , Lu Ling Wu
2007, 18(2): 121-123  doi: 10.1016/j.cclet.2006.12.004
[Abstract](218) [FullText HTML] [PDF 260KB](0)
A series of 2,4-dibromobutenes were synthesized by the reaction of methylenecyclopropanes with KBr in HOAc in the presence of dibenzoyl peroxide, providing an environment friendly method for the synthesis of 2,4-dibromobutenes.
Synthesis and antitumor activity of water-soluble poly(aminoheterocyclic amine)s (Ⅰ):N,N,N',N'-tetra[2-(4-amino-5-substituted-s-triazol-3-yl sulfanyl)ethyl]-1,4-benzyldiamine salts
Guo Qiang Hu , Song Qiang Xie , Wen Long Huang
2007, 18(2): 124-126  doi: 10.1016/j.cclet.2006.12.001
[Abstract](190) [FullText HTML] [PDF 246KB](0)
Five water-soluble poly(aminoheterocyclic amine)s containing s-triazole ring were synthesized as respective HCl salts (5a-5e).Biological activities in L1210 (murine leukemia) and Chinese hamster ovary (CHO) cell lines were investigated via IC50cytotoxicity determinations. The title compounds represented moderate cytotoxicity (low IC50 values between 15 and 68 μmol/L)in L1210 but high cytotoxicity (lower IC50 values:0.25, 0.018, 0.014 μmol/L for 5a-5e, respectively) in CHO cell lines, while the corresponding HCl salts of the intermediates (3a-3e) without polyamine tether and starting materials amino-s-triazoles (1a-1e)showed poor or no activities against the above cell lines.
Rhodium-catalyzed asymmetric ring opening of azabenzonorbornadiene with substituted piperazine nucleophiles
Lei Xie , Ding Qiao Yang , Shuang Qi Zhao , Huan Wang , Li Hua Liang , Ren Shi Luo
2007, 18(2): 127-129  doi: 10.1016/j.cclet.2006.12.003
[Abstract](190) [FullText HTML] [PDF 204KB](0)
We have developed an asymmetric ring opening reaction of azabenzonorbornadiene with substituted piperazine. By increasing the amount of catalyst (from 2.5 to 5%) and ligands (5 to 10%) as well as addition of ammonium iodide, the products can be obtained in high yield and the reaction time shortened dramatically, but the ee values were rather low.
A facile electrochemical synthesis of caffeic acid derivatives in the presence of acetylacetone or methyl acetoacetate in aqueous medium
Cheng Chu Zeng , Li Ming Hu , Jia Zeng , Ru Gang Zhong
2007, 18(2): 130-132  doi: 10.1016/j.cclet.2006.12.010
[Abstract](212) [FullText HTML] [PDF 306KB](0)
The anodic oxidation of caffeic acid in the presence of acetylacetone or methyl acetoacetate in aqueous solution has been studied by cyclic voltammetry and controlled-potential electrolysis techniques. The result showed that caffeic acid was oxidized to the corresponding o-benzoquinone, which underwent further Michael-addition with acetylacetone or methyl acetoacetate to produce caffeic acid derivative 3,4-dihydroxy-6-(1-acetylacetone)-yl cinnamic acid 4a or 3,4-dihydroxy-6-(1-acetyl-methylacetate)-ylcinnamic acid 4b.
Aerobic oxidation assisted by ligand-free palladium catalysts
Jia Rui Wang , Chu Ting Yang , Lei Liu , Qing Xiang Guo
2007, 18(2): 133-136  doi: 10.1016/j.cclet.2006.12.005
[Abstract](197) [FullText HTML] [PDF 204KB](0)
Aerobic oxidation of electron-rich benzylic and phenyl allylic alcohols was achieved with high yields with only 0.1 mol.% of Pd(OAc)2 catalyst in the absence of any ligand. This procedure was expected to be valuable for realistic industrial-scale applications from both economic as well as environmental points of view.
Regioselective synthesis and anti-HIV activity of the novel 2-and 4-substituted pyrazolo[4,5-e] [1,2,4]thiadiazines
Xin Yong Liu , Ren Zhang Yan , Nian Gen Chen , Wen Fang Xu
2007, 18(2): 137-140  doi: 10.1016/j.cclet.2006.12.006
[Abstract](199) [FullText HTML] [PDF 256KB](0)
The new regioisomer 7-methyl-pyrazolo[4,5-e] [1,2,4]thiadiazine nucleus (5) was synthesized, and its novel mono-N2-or N4-substituted pyrazolo[4,5-e] [1,2,4]thiadiazines (6, 7) were regioselectively prepared by deprotonation of NN2 or/and N4 atoms with different molar ratio of NaH and alkyl halides. Anti-HIV-1 screening tests showed some compounds to be potent as HIV-1 nonnucleoside reverse transcriptase inhibitors (HIV-1 NNRTIs).
A new series of emodin derivatives with bone affinity
Hong Chen , Ying Wang , Ling Leng , Mao Sheng Cheng , Peng Fei Yu , Jing Ze Zhang
2007, 18(2): 141-144  doi: 10.1016/j.cclet.2006.12.021
[Abstract](162) [FullText HTML] [PDF 241KB](0)
A new series of bone affinity compounds were synthesized by linking emodin with 5-fluorouracil derivatives. Their bone affinities were established by hydroxyapative (HA) affinity experiment in vitro, and their cytostatic effects were shown by the MTT assay.
Synthesis of cystine C60 derivative and its protective effects on hydrogen peroxide-induced apoptosis in PC12 cells
Zhen Hu , Hai Ping Xing , Zhou Zhu , Wei Wang , Wen Chao Guan
2007, 18(2): 145-148  doi: 10.1016/j.cclet.2006.12.023
[Abstract](158) [FullText HTML] [PDF 868KB](0)
Oxidative stress has been considered as a major cause of cellular injuries in a variety of clinical abnormalities, especially prominent in neural diseases. One of the usable ways to prevent the reactive oxygen species (ROS)-mediated cellular injury is dietary or pharmaceutical augmentation of some free radical scavenger. Water-soluble amino-fullerene is a novel compound that behaves as a free radical scavenger with excellent biology consistent. In the present study, we have synthesized and characterized a novel cystine C60 derivative for the first time, and investigated the effects on hydrogen peroxide-induced oxidative stress and apoptotic death in cultured rat pheochromocytoma (PC12) cells. PC12 cells treated with hydrogen peroxide underwent apoptotic death as determined by MTT, PI/Hoechst 33342 staining and flow cytometry analysis. These results suggested that cystine C60 derivative has the potential to prevent oxidative stress-induced cell death and has no evident toxicity.
Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea under mild conditions
Jun Jie Gao , Hui Quan Li , Yi Zhang
2007, 18(2): 149-151  doi: 10.1016/j.cclet.2006.12.014
[Abstract](156) [FullText HTML] [PDF 221KB](1)
Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.
A new alkaloid from Stemona sessilifolia
Peng Wang , Hai Lin Qin , Zhi Hong Li , Ai Lin Liu , Guan Hua Du
2007, 18(2): 152-154  doi: 10.1016/j.cclet.2006.12.007
[Abstract](157) [FullText HTML] [PDF 263KB](0)
A new alkaloid, named sessilistemonamine D, was isolated from the roots of Stemona sessilifolia and the structure and relative configuration were determined on the basis of NMR and MS spectrometric data analysis.
Two new phenylethanoid glycosides from the roots of Phlomis umbrosa
Pu Liu , Yoshihisa Takaishi , Hong Quan Duan
2007, 18(2): 155-157  doi: 10.1016/j.cclet.2006.12.019
[Abstract](168) [FullText HTML] [PDF 203KB](0)
Two new phenylethanoid glycosides were isolated from the roots of Phlomis umbrosa. Their structures were elucidated by spectroscopic methods.
New flavone and isoflavone glycoside from Belamcanda chinensis
Li Jin , Hai Sheng Chen , Zhao Bao Xiang , Shuang Liang , Yong Sheng Jin , Jian Guo Liu
2007, 18(2): 158-160  doi: 10.1016/j.cclet.2006.12.031
[Abstract](157) [FullText HTML] [PDF 214KB](0)
The new flavone, 5,4'-dihydroxy-6,7-methylenedioxy-3'-methoxyflavone, and one new isoflavone glycoside, 3',5'-dimethoxy irisolone-4'-O-β-D-glucoside were isolated from the rhizomes of Belamcanda chinensis. Their structures were established based on the spectroscopic methods.
A new triterpene glycoside from sea cucumber Holothuria leucospilota
Hua Han , Yang Hua Yi , Ling Li , Xiao Hua Wang , Bao Shu Liu , Peng Sun , Min Xiang pan
2007, 18(2): 161-164  doi: 10.1016/j.cclet.2006.12.027
[Abstract](170) [FullText HTML] [PDF 238KB](0)
A new triterpene glycoside, leucospilotaside A, along with a known saponin, isolated from sea cucumber Holothuria leucospilota, and its structure was elucidated as 3β-O-[4-O-sodiumsulfate-β-D-quinovopyranosyl-(1→2)-β-D-xylopyranosyl]-holosta-22-ketone-9-en-17α,25α-diol (1) by extensive spectroscopic analysis and chemical methods. Leucospilotaside A (1) has a ketone carbonyl group (22) in the aglycon side chain.
Hydroxylation of nigranoic acid to 6β-hydroxynigranoic acid by Caryospora carllicarpa YMF1.01026
Jin Yan Dong , Ye Gao Chen , Hong Chuan Song , Yan Ping He , Lei Li , Yong Ping Zhong , Yan Hui Zhu , Jie Cao , Luo Wang , Ke Qin Zhang
2007, 18(2): 165-167  doi: 10.1016/j.cclet.2006.12.020
[Abstract](162) [FullText HTML] [PDF 218KB](0)
Microbial transformation of nigranoic acid by Caryospora carllicarpa YMF1.01026 afforded the new derivative 6β-hydroxynigranoic acid. Its structure was elucidated by spectroscopic methods.
Neolignan glycoside from Angelica dahurica
Xing Zeng Zhao , Xu Feng , Xiao Dong Jia , Yun Fa Dong , Ming Wang
2007, 18(2): 168-170  doi: 10.1016/j.cclet.2006.12.011
[Abstract](156) [FullText HTML] [PDF 250KB](0)
A new neolignan glycoside, 4-O-β-D-glucopyranosyl-9-O-β-D-glucopyranosyl-(7R, 8S)-dehydrodiconiferyl alcohol was isolated from the fresh roots of Angelica dahurica. The structure of the new compound was elucidated on the basis of spectral analysis.
Two new saponins from Anemarrhena asphodeloides Bge
Ying Peng , Yu Jing Zhang , Zhi Qiang Ma , Wei San Pan , Yu Qing Sun , Shao Jiang Song
2007, 18(2): 171-174  doi: 10.1016/j.cclet.2006.12.009
[Abstract](168) [FullText HTML] [PDF 235KB](0)
Two new saponins 3-O-β-D-glucopyranosyl (1→2)-β-D-mannopyranosyl sarsasapogenin, named timosaponin A Ⅳ(1) and(5β, 25S)-26-O-β-D-glucopyranosyl-furost-20(22)-en-3,26-diol-3-O-β-D-glucopyranosyl (1→4) glucopyranosyl (1→2)-β-D-galacopyranoside, named timosaponin B Ⅳ(2), were isolated by silica gel column chromatography and preparative HPLC from Anemarrhena asphodeloides Bge. Their structures were elucidated by chemical characters and spectroscopic analysis.
A new veratramine alkaloid from the bulbs of Fritillaria hupehensis
Yong Hui Zhang , Xi Liang Yang , Xue Feng Zhou , Han Li Ruan , Hui Fang Pi , Ji Zhou Wu , Han Dong Sun , Tetsuro Fujita
2007, 18(2): 175-177  doi: 10.1016/j.cclet.2006.12.037
[Abstract](166) [FullText HTML] [PDF 214KB](0)
A new highly conjugated alkaloid of veratramine type, 22S,25S,5α-veratramine-7(8), 12(14)-diene-3β,13β,23β-triol-6-one (1),was isolated from the bulbs of Fritillaria hupehensis Hsiao et K.C. Hsia. Its structure was determined on the basis of spectroscopic evidences.
Two new aristolane sesquiterpenes from Laurencia similis
Nai Yun Ji , Xiao Ming Li , Lan Ping Ding , Bin Gui Wang
2007, 18(2): 178-180  doi: 10.1016/j.cclet.2006.12.043
[Abstract](162) [FullText HTML] [PDF 236KB](0)
Two new aristolane sesquiterpenes, namely, aristolan-10-ol-9-one and aristolan-8-en-1-one, were isolated from the red alga Laurencia similis. Their structures were established on the basis of various NMR spectroscopic analyses, including 2D NMR techniques (1H-1H COSY, HMQC, HMBC, and NOESY) and HR-FAB-MS.
New ceramides from the flower of Albizia julibrissin
Jian Kang , Chang Hong Huo , Zhe Li , Zuo Ping Li
2007, 18(2): 181-184  doi: 10.1016/j.cclet.2006.12.042
[Abstract](168) [FullText HTML] [PDF 236KB](0)
A new ceramide and its glycoside were isolated from the flower of Albizia julibrissin. Their structures were established as (2S,3S,4R,8E)-2-[(2'R)-hydroxyhexadecanoylamino]-8-tetra-cosene-1,3,4-triol (Ⅰ) and 1-O-β-D-glucopyranosyl-(2S,3S,4R,8E)-2-[(2'R)-hydroxy-hexade-canoylamino]-8-tetracosene-1,3,4-triol (II) on the basis of chemical and spectroscopic studies.
Organic/inorganic nanocomposite polymer electrolyte
Li Qi , Shao Jun Dong
2007, 18(2): 185-188  doi: 10.1016/j.cclet.2006.12.038
[Abstract](158) [FullText HTML] [PDF 260KB](0)
The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocom posites membrane materials and their lithium salt complexes have been found thermally stable below 200℃. The conductivity of the organic/inorganic nanocomposites polymer electrolytes prepared at room temperature was at magnitude range of 10-6 S/cm.
A novel sensitive non-enzymatic glucose sensor
Xin Huang Kang , Zhi Bin Mai , Xiao Yong Zou , Pei Xiang Cai , Jin Yuan Mo
2007, 18(2): 189-191  doi: 10.1016/j.cclet.2006.12.034
[Abstract](163) [FullText HTML] [PDF 721KB](0)
Cu nanoclusters were electrochemically deposited on the film of a Nafion-solubilized multi-wall carbon nanotubes (CNTs) modified glassy carbon electrode (CNTs-GCE), which fabricated a Cu-CNTs composite sensor (Cu-CNTs-GCE) to detect glucose with non-enzyme. The linear range is 7.0×10-7 to 3.5×10-3 mol/L with a high sensitivity of 17.76 μA/(mmol L), with a low detection limit 2.1×10-7 mol/L, fast response time (within 5 s), good reproducibility and stability.
Facile O-alkylation of highly hydrophilic hyperbranched polyglycerol
De Cheng Wan , Jun Jie Yuan , Zheng Long Yang , Hong Ting Pu
2007, 18(2): 192-194  doi: 10.1016/j.cclet.2006.12.035
[Abstract](165) [FullText HTML] [PDF 234KB](0)
A facile and selective route for O-alkylation of highly hydrophilic, multifunctional hyperbranched polyglycerol (PG) under nonaqueous phase transfer catalyzed conditions in dimethyl sulfoxide was developed, through which several kinds of groups were introduced onto PG.
Determination of trace calcium by solid substrate-room temperature phosphorimetry
Jia Ming Liu , Tian Long Yang , Xiao Mei Huang , Xiu Mei Shi , Zhong Bin Shi , Hong Wu , Guo Hui Zhu , Zhi Ming Li , Cui Lian Chen
2007, 18(2): 195-197  doi: 10.1016/j.cclet.2006.12.016
[Abstract](168) [FullText HTML] [PDF 245KB](0)
A new method for the determination of trace calcium by solid substrate-room temperature phosphorimetry is established. It is based on the fact that chromeazurols azurol S-phenanthroline-NaCMC (CAS-phen-NaCMC) system can emit strong and stable room temperature phosphorescence (RTP) on the solid substrate in the filter paper. Ca2+ and phenanthroline can form complex ion Ca(phen)32+, which will form complex [Ca(phen)3(CAS)2] with CAS. In the result, the number of CAS molecules in each spot increased, causing sharp increase of the RTP signal of the CAS-phen-NaCMC system.
Highly sensitive ECL-PCR method for detection of K-ras point mutation
De Bin Zhu , Da Xing , Ya Bing Tang
2007, 18(2): 198-200  doi: 10.1016/j.cclet.2006.12.017
[Abstract](158) [FullText HTML] [PDF 228KB](0)
A highly sensitive electrochemiluminescence-polymerase chain reaction (ECL-PCR) method for K-ras point mutation detection is developed. Briefly, K-ras oncogene was amplified by a Ru(bpy)32+ (TBR)-labeled forward and a biotin-labeled reverse primer,and followed by digestion with MvaI restriction enzyme, which only cut the wild-type amplicon containing its cutting site. The digested product was then adsorbed to the streptavidin-coated microbead through the biotin label and detected by ECL assay. The experiment results showed that the different genotypes can be clearly discriminated by ECL-PCR method. It is useful in point mutation detection, due to its sensitivity, safety, and simplicity.
Determination of neomycin in water samples by high performance anion chromatography with pulsed amperometric detection
Bin Guan , Dong Xing Yuan
2007, 18(2): 201-204  doi: 10.1016/j.cclet.2006.12.022
[Abstract](157) [FullText HTML] [PDF 240KB](0)
A simple, fast and reliable method, using high performance anion chromatography with pulsed amperometric detection, had been developed for the analysis of neomycin in water samples. The elution and separation were carried out with an isocratic mobile phase, containing 10 mmol/L NaOH. The influence of the concentration and pH of the mobile phase on the separation and detection was investigated. A quadruple-potential waveform used for the detection was optimized. The detection limit of neomycin was down to 0.027 μg/mL. The linearity of neomycin calibration curve ranged from 0.050 to 0.505 μg/mL with correlation coefficient of0.9997. R.S.D. (n=11) was 4.0%.
Study on the bioactivity changes of hydroxylated sulfonylureas derivatives:A possible metabolism
Shu Rong Ban , Cong Wei Niu , Wen Bin Chen , Zhi Hong Yu , Si Wu , Chen Wang , Zhen Xi
2007, 18(2): 205-208  doi: 10.1016/j.cclet.2006.12.012
[Abstract](141) [FullText HTML] [PDF 629KB](0)
Some new sulfonylureas and their hydroxylation products had been synthesized from 2-amino-4-methylpyrimidine. Their bioactivities against E. Coli AHAS Ⅱ in vitro were tested and the results indicated that the hydroxylation decreased the inhibition activities of sulfonylureas significantly. Subsequently herbicidal tests against stem-growth of barnyard grass and root-growth of rape confirmed the above conclusion. The preliminary molecular docking studies were also carried out to investigate the binding modes of non-hydroxylated and hydroxylated sulfonylureas with AHAS.
Synthesis and properties of novel aliphatic polycarbonate from carbon dioxide with 1,2-butylene oxide and ε-caprolactone
Yan Fei Liu , Ke Long Huang , Dong Ming Peng , Su Qin Liu , Hong Wu
2007, 18(2): 209-212  doi: 10.1016/j.cclet.2006.12.002
[Abstract](153) [FullText HTML] [PDF 395KB](0)
A new degradable aliphatic poly(butylene-co-ε-caprolactone carbonate) (PBCL) was synthesized through the terpolymerization of carbon dioxide, 1,2-butylene oxide (BO) and ε-caprolactone (CL), a polymer supported bimetallic complex (PBM) was used as a catalyst. The terpolymers prepared were characterized by FT-IR, 1H NMR, 13C NMR, WXRD and DSC. The hydrolysis tests were carried out to appraise the degradability of the copolymers.
Preparation and characterization O-lauroyl chitosan/poly (L-lactic acid) blend membranes by solution-casting approach
Yao Zu Liao , Mei Hua Xin , Ming Chun Li , Sheng Su
2007, 18(2): 213-216  doi: 10.1016/j.cclet.2006.12.024
[Abstract](138) [FullText HTML] [PDF 687KB](0)
O-Lauroyl chitosan/poly(L-lactide) (OCS/PLLA) blend membranes with different compositions were prepared by solutioncasting approach using chloroform as common solvent. The experimental results of FT-IR, DSC and WAXD indicated that interassociation hydrogen-bond interactions existed between OCS and PLLA in the blend membranes. And SEM observation confirmed that the blend membranes with suitable compositions were compatible.
The effect of polymerization conditions on crystalline of polybutene-1 catalyzed by metallocene catalyst
Qi Gu Huang , Ya Ping Sheng , Kun Xue Deng , Li Fu Ma , Yi Xian Wu , Wan Tai Yang
2007, 18(2): 217-220  doi: 10.1016/j.cclet.2006.12.030
[Abstract](128) [FullText HTML] [PDF 225KB](0)
Polybutene-1 was synthesized stereoselectively with the precursor η5-(pentamethyl-cyclopentadienyl) tribenzyloxide titanium (Cp*Ti(Obz)3) and methylaluminoxane (MAO). The effects of polymerization conditions, trimethyl alumina (TMA) content in MAO and temperature on the crystalline and molecular weight of the products, and catalytic activity were investigated. The structural properties of the polybutene-1 were characterized with 13C NMR and WAXD.
Fabrication of a novel poly(dimethylsiloxane) microchips with two sharpened stretching tips
Chun Ye Liu , Xu Xu , Hong Jun Gao , Jie Rong Chen
2007, 18(2): 221-224  doi: 10.1016/j.cclet.2006.12.036
[Abstract](141) [FullText HTML] [PDF 925KB](0)
An integrated poly(dimethylsiloxane) (PDMS) microchip with two sharpened stretching has been presented. The sample was directly introduced into the separation channel through the stretching inlet tip without complicated power switching supplies and without injection cross-channel. Operations of running buffer refreshing or channel cleaning also becomes simple by vacuumed in one end and placed another tip into solution vial. The fabrication method can be easily applied in most analytical laboratories at low cost in the absence of soft lithography and plasma bonding equipments. Characteristics of the chips were tested and it can be used to separate fluorescence labeled molecules.
Cure reaction and phase behavior of liquid crystalline epoxides-anhydride systems
Li Yan Liang , Shao Ping Ren , Yi Quan Zheng , Man Geng Lu
2007, 18(2): 225-228  doi: 10.1016/j.cclet.2006.12.040
[Abstract](134) [FullText HTML] [PDF 812KB](0)
A series of novel liquid crystalline epoxides with lateral substituents were cured with anhydrides and the cure kinetics was investigated by non-isothermal DSC technique. The results showed that the lengths of lateral substituents have great effect on the value of Ea. The curing reaction became less active, when the liquid crystalline epoxides have long lateral substituents and were controlled by diffusion at the late stage of cure. A nematic structure was observed by POM and XRD.
Studies on the synthesis and properties of malachite green imprinted polymer
Li Qiang Su , Shi Qiao , Wei Bing Zhang
2007, 18(2): 229-232  doi: 10.1016/j.cclet.2006.12.013
[Abstract](149) [FullText HTML] [PDF 247KB](0)
A new molecularly imprinted polymer was synthesized with malachite green (MG) as molecular template, methacrylic acid (MAA) as functional monomer, ethylene dimethacrylate (EDMA) as crosslinker, and azobisisobutyronitrile (AIBN) as initiator.Recognition properties of the MG imprinted polymer were studied by equilibrium adsorption and HPLC. The results showed that the imprinted polymer had good affinity and marked selectivity for MG, and can separate MG with its analogue commendably. The new polymer can be used for the enrichment of MG in complex sample, and can work as separation media to separate and detect MG by HPLC.
Equilibrium and kinetic studies on the adsorption of VB12 onto CMK-3
Zhuo Guo , Li Feng Wang , Zhan Gao , Wei Wei Zhang
2007, 18(2): 233-236  doi: 10.1016/j.cclet.2006.12.032
[Abstract](134) [FullText HTML] [PDF 294KB](0)
The adsorption of VB12 onto CMK-3 was studied as a function of temperature and initial VB12 concentration. The highest VB12adsorption capacity was determined as 353.4 mg/g at 40℃. Adsorption data were well described by the Langmuir model, although they could be modelled by the Freundlich equation. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data. The pseudo-second-order kinetic model provided the best correlation of the experimental data compared to the pseudo-first-order model.
A novel synthetic route for LiFePO4/C cathode materials by addition of starch for lithium-ion batteries
Shao Hua Luo , Zi Long Tang , Jun Biao Lu , Zhong Tai Zhang
2007, 18(2): 237-240  doi: 10.1016/j.cclet.2006.12.041
[Abstract](138) [FullText HTML] [PDF 892KB](0)
LiFePO4/Carbon composite cathode material was prepared using starch as carbon source by spray-pelleting and subsequent pyrolysis in N2. The samples were characterized by XRD, SEM, Raman, and their electrochemical performance was investigated in terms of cycling behavior. There has a special micro-morphology via the process, which is favorable to electrochemical properties.The discharge capacity of the LiFePO4/C composite was 170 mAh g-1, equal to the theoretical specific capacity at 0.1 C rate. At4 C current density, the specific capacity was about 80 mAh g-1, which can satisfy for transportation applications if having a more flat discharge flat.
Gas-phase photocatalytic oxidation of benzene over titanium dioxide loaded on Bi12TiO20
Tao Lin , Zhan Pi , Mao Chu Gong , Jun Bo Zhong , Jian Li Wang , Yao Qiang Chen
2007, 18(2): 241-243  doi: 10.1016/j.cclet.2006.12.008
[Abstract](142) [FullText HTML] [PDF 216KB](0)
TiO2 was prepared by sol-gel method using tetrabutyl titanate as precursor. TiO2 was loaded on Bi12TiO20. The photocatalyst with different TiO2 loading was calcined at 723 K. The photocatalytic activity of decomposition gaseous benzene was investigated in a batch reactor. The prepared photocatalyst was characterized by UV-vis diffuse reflectance. The result showed that TiO2/Bi12TiO20 absorbed much more ultraviolet light than TiO2 in the ultraviolet light region and showed red shift. The results indicated that the prepared photocatalyst can greatly promote the photocatalytic activity. The 2.0% TiO2/Bi12TiO20 system exhibited the highest photocatalytic activity.
Theoretical study on conformational conversion of 1,3-dioxane inside a capsular host
Ju Wang , Zuo Yin Yang , Xiu Li Wang , Jing Chang Zhang , Wei Liang Cao
2007, 18(2): 244-246  doi: 10.1016/j.cclet.2006.12.039
[Abstract](140) [FullText HTML] [PDF 903KB](0)
The conformational conversion of 1,3-dioxane guest encapsulated inside a cylindrical capsular host was investigated with PM3method and single point energies were evaluated by B3LYP method. When entrapped in the capsule, the guest tumbles were slower than that in the free condition. The influences of the inner phase of the capsule on the guest conformational conversion were discussed in detail.
Address:Zhongguancun North First Street 2,100190 Beijing, PR China Tel: +86-010-82449177-888
Powered By info@rhhz.net