2007 Volume 18 Issue 10

A facile one-pot synthesis of new thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione derivatives
A. Davoodnia , H. Behmadi , A. Zare Bidaki , M. Bakavoli , N. Tavakoli Hoseini
2007, 18(10): 1163-1165  doi: 10.1016/j.cclet.2007.07.024
[Abstract](182) [FullText HTML] [PDF 245KB](0)
Abstract:
A facile one-pot synthesis of new 3-arylthieno[2, 3-d]pyrimidine-2, 4(1H, 3H)-diones via base-catalyzed cyclocondensation of ethyl 2-amino-4, 5-dimethylthiophene-3-carboxylate with aryl isocyanates is described.
Synthesis of aromatic-linked polyamine macrocyclic derivatives as HIV-1 entry inhibitors
Jing Su , Yao Liu , Zhi Bing Zheng , Jun Hai Xiao , Hong Lu , Wu Zhong , Li Li Wang , Shi Bo Jiang , Song Li
2007, 18(10): 1166-1168  doi: 10.1016/j.cclet.2007.08.021
[Abstract](197) [FullText HTML] [PDF 253KB](0)
Abstract:
A series of novel aromatic-linked polyamine macrocyclic derivatives have been synthesized, Their structures were confirmed by MS and 1H NMR. These compounds exhibited potent anti-HIV-1 activities.
The synthesis and activity in vitro of a series of 8-difluoromethoxy quinolones:Analogues of gemifloxacin
Jin Jiang , Jiu Yu Liu , Hui Yuan Guo
2007, 18(10): 1169-1172  doi: 10.1016/j.cclet.2007.07.030
[Abstract](193) [FullText HTML] [PDF 273KB](0)
Abstract:
7-[4-(Aminomethyl)-3-(methoxyimino)pyrrolidin-1-yl]-1-cyclopropyl-6-fluoro-8-difluoromethoxy-1, 4-dihydro-4-oxoquino-line-3-carboxylic acid and its analogues have been prepared and evaluated for antibacterial activity in vitro.
An efficient and facile procedure for synthesis of octyl polyglucoside
Ying Wu , Jiu Gao Yu , Xiao Fei Ma , Jian She Zhang
2007, 18(10): 1173-1175  doi: 10.1016/j.cclet.2007.07.023
[Abstract](192) [FullText HTML] [PDF 259KB](0)
Abstract:
Nonionic surfactant alkyl polyglucoside (APG) was prepared by direct glycosidation of alkyl alcohol with glucose in the presence of sulfate acid-silica gel (H2SO4/SiO2) as solid acidic catalyst. The quantity of catalyst was only of 1 wt%, based on the glucose, and the conversion of glucose was close to 100% at 110℃ in 1.5 h. The product was characterized by FT-IR, mass and 1H NMR spectra. The degree of polymerization (DP) of the glucose in the product was 1.37, and critical micelle concentration (CMC)of product was only 0.0104 wt%.
Synthesis of new tetrazene (N-N=N-N)-linked bi (1,2,4-triazole)
Sheng Hua Li , Si Ping Pang , Xiao Tong Li , Yong Zhong Yu , Xin Qi Zhao
2007, 18(10): 1176-1177  doi: 10.1016/j.cclet.2007.08.018
[Abstract](275) [FullText HTML] [PDF 194KB](0)
Abstract:
The reaction of 4-amino-1, 2, 4-triazole with sodium dichloroisocyanurate (SDCI) afforded new tetrazene(N-N=N-N)-linked bi(1, 2, 4-triazole) 2a in excellent yield. Increasing the molar ratio of SDCI to 4-amino-1, 2, 4-triazole, the chlorinated product 1, 5, 5'-trichloro-4, 4'-azo-1, 2, 4-triazole (2b) was formed. These new compounds have been characterized by MS, 1H NMR, 13C NMR, and elemental analysis.
Polyphosphorous acid catalyzed cyclization in the synthesis of cryptolepine derivatives
Sheng Biao Wan , Zhe Lin Liu , Di Chen , Qing Ping Dou , Tao Jiang
2007, 18(10): 1178-1181  doi: 10.1016/j.cclet.2007.08.014
[Abstract](182) [FullText HTML] [PDF 215KB](0)
Abstract:
11-Oxo-10, 11-dihydroxy-5H-indolo[3, 2, b]quinoline 7-carboxylic acid was obtained specifically by polyphosphorous acid catalyzed cyclization with optimal reaction conditions. Biological assays showed that it potentially inhibits the proteasomal chymotrypsin-like activity in vitro and suppresses breast cancer cell growth.
Non-surfactant synthesis of mesoporous silica with dye as template
Peng Feng , Yao Xu , Dong Wu
2007, 18(10): 1182-1186  doi: 10.1016/j.cclet.2007.08.015
[Abstract](202) [FullText HTML] [PDF 847KB](0)
Abstract:
A novel non-surfactant method was described to synthesize mesoporous silica using dye basic fuchsin as template. Chemical reactions were introduced into the formation of mesopores rather than the weak electrostatic or hydrogen-bonding interactions in the traditional surfactant routes. The reactant composition was found to be crucial to the pore structure of objective product. The formation mechanism of mesopore was also proved.
Cationic ring-opening polymerization of 3,3-bis (chloromethyl) oxacyclobutane in ionic liquids
Yuan Yuan Wang , Wei Li , Li Yi Dai
2007, 18(10): 1187-1190  doi: 10.1016/j.cclet.2007.08.013
[Abstract](195) [FullText HTML] [PDF 234KB](0)
Abstract:
Cationic ring-opening polymerization of 3, 3-bis(chloromethyl)oxacyclobutane catalyzed by BF3·OEt2 was carried out in ionic liquids[bmim]BF4 and[bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO/BF3·OEt2 on the molecular weights and yield of PBCMO were investigated. The polymerization in ionic liquids proceed to high conversions, although molecular weights are limited, similar to polymerization in organic solvent such as CH2Cl2. Follow a viewpoint of green chemistry, we feel ionic liquid[bmim]BF4 is superior to[bmim]PF6. Extracting[bmim]PF6 from the product using organic solvent as extractant limits its advantage as a green reaction media.
Design,synthesis and antiproliferative activities of novel 5H-pyridazino[4,5-b]indoles
Rong Dong Li , Xin Zhai , Yan Fang Zhao , Ping Gong
2007, 18(10): 1191-1194  doi: 10.1016/j.cclet.2007.07.027
[Abstract](200) [FullText HTML] [PDF 249KB](0)
Abstract:
A novel series of 5H-pyridazino[4, 5-b]indoles were designed and synthesized in order to find novel potent anticancer compounds. The structures were confirmed by 1H NMR and MS. Their antiproliferative activities against two cancer cell lines were tested by the MTT method in vitro. Three of compounds (1e, 1g, and 1h) exhibited potent antiproliferative activities, especially compound 1h (with IC50 values of 5.2 μmol/L and 1.9 μmol/L against Bel-7402 and HT-1080, respectively). The preliminary structure-activity relationships of 5H-pyridazino[4, 5-b]indole derivatives were discussed.
Synthesis and antitumor activity of derivatives of 23-hydroxybetulinic acid
Jin Pei Zhou , Dan Li , Xiao Ming Wu , Wen Cai Ye , Lu Yong Zhang
2007, 18(10): 1195-1198  doi: 10.1016/j.cclet.2007.07.017
[Abstract](186) [FullText HTML] [PDF 271KB](0)
Abstract:
A series of natural product 23-hydroxybetulinic acid derivatives were prepared. In the preparation of mono-O-benzoyl ester derivative, it was observed that benzoyl group migrated from 3-O-to 23-O-position during the detritylation.
Cu-catalyzed cross-couplings under ligandless conditions
Chuan Zhou Tao , Juan Li , Xin Cui , Yao Fu , Qing Xiang Guo
2007, 18(10): 1199-1202  doi: 10.1016/j.cclet.2007.07.016
[Abstract](193) [FullText HTML] [PDF 226KB](0)
Abstract:
The possibility to carry out Cu-catalyzed cross-couplings under ligandless conditions was studied. It was found that by using K3PO4 as the base, the cross-coupling could proceed successfully between aryl iodides and several types of nucleophiles. Aryl bromides were completely inactive under the same reaction conditions.
Synthesis and characterization of novel polyimides based on thiazole-containing diamine
Xin Zhao , Yan Feng Li , Shu Jiang Zhang , Xiao Long Wang , Yu Shao
2007, 18(10): 1203-1204  doi: 10.1016/j.cclet.2007.08.007
[Abstract](280) [FullText HTML] [PDF 206KB](0)
Abstract:
A new kind of aromatic diamine monomer containing thiazole unit, 2-amino-5-(4-aminophenyl)-thiazole (AAPT), was synthesized in three steps, starting from 4-nitroacetophenone. A novel thiazole-containing polyimide was prepared via the polycondensation of AAPT with 6FDA by one-step method. The resulting polyimide exhibits excellent solubility, film-forming capability and high thermal resistance.
Synthesis and application of an IL-supported diol as protecting group for aldehydes
Yue Qin Cai , Ye Liu , Guo Hua Gao
2007, 18(10): 1205-1208  doi: 10.1016/j.cclet.2007.07.012
[Abstract](198) [FullText HTML] [PDF 213KB](0)
Abstract:
A new IL-supported diol, 1-(2, 3-dihydroxypropyl)-3-methylimidazolium hexafluorophosphate has been synthesized and characterized by FT-IR, 1H NMR, 13C NMR and MS (ESI). Its physical properties such as freezing point, solubility and specific gravity and thermal stability were determined. Synthetic utilities of the resultant diol as a protecting group for aldehydes were also investigated.
A novel highly selective fluorescent chemosensor for Hg (Ⅱ) in fully aqueous media
Xiang Ming Meng , Man Zhou Zhu , Qing Xiang Guo
2007, 18(10): 1209-1212  doi: 10.1016/j.cclet.2007.08.003
[Abstract](193) [FullText HTML] [PDF 342KB](0)
Abstract:
A novel fluorescent Hg2+ chemosensor based on dithia-dioxa-monoaza crown ether was synthesized in four steps from inexpensive starting materials. This new sensor exhibited very strong fluorescence response to Hg2+ (FHg2+/Ffree >130) and it was highly selective to Hg2+ over the other metal ions by more than 45-fold.
Zirconyl chloride promoted highly efficient solid phase synthesis of amide derivatives
Cherkupally Sanjeeva Reddy , Adki Nagaraj , Pochampally Jalapathi
2007, 18(10): 1213-1217  doi: 10.1016/j.cclet.2007.08.011
[Abstract](193) [FullText HTML] [PDF 525KB](0)
Abstract:
An efficient solid phase route for the synthesis of amide derivatives by the reaction of carboxylic acids with urea in the presence of catalytic amount of zirconyl chloride under microwave irradiation conditions was described. In this way, a range of interesting amide derivatives was obtained in good to excellent yields. The catalyst was recycled with fresh reactants and it gave almost similar results without significant loss of activity up to the third run.
Two new glycosides from the genus of Cassia
Zhu Ju Wang , Qiu Ping Wu , Li Ying Tang , Mei Hong Fu , Yan He , Qian Feng Gong , Lu Qi Huang
2007, 18(10): 1218-1220  doi: 10.1016/j.cclet.2007.08.004
[Abstract](191) [FullText HTML] [PDF 237KB](1)
Abstract:
Two new glycosides were isolated and characterized by spectral analysis from the seeds of Cassia obtusifolia and the leaves of Cassia angustifolia. The structure was elucidated as 1-hydroxyl-2-acetyl-3, 8-dimethoxynaphthalene-6-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside and 2-acetyl-3-methyl-8-methoxyl-1, 4-naphthoquinone-6-O-β-D-glucopyranoside.
A new iridoid glycoside from Gardenia jasminoides
Xiao Qin Zhou , Zhi Ming Bi , Ping Li , Dan Tang , Hai Xia Cai
2007, 18(10): 1221-1223  doi: 10.1016/j.cclet.2007.08.019
[Abstract](190) [FullText HTML] [PDF 228KB](0)
Abstract:
A new iridoid glycoside, 6'-O-sinapoylgeniposide, was isolated from Gardenia jasminoides Ellis and its structure was elucidated on the basis of 1D and 2D NMR, HR-ESI-MS techniques.
A new sesquilignan from Selaginella sinensis (Desv.) Spring
Yan Zhi Wang , Hui Chen , Xiao Ke Zheng , Wei Sheng Feng
2007, 18(10): 1224-1226  doi: 10.1016/j.cclet.2007.08.016
[Abstract](186) [FullText HTML] [PDF 249KB](0)
Abstract:
A new sesquilignan, namely sinensiol A, was isolated from the plant of Selaginella sinensis (Desv.) Spring. Its structure was identified on the basis of various spectroscopic data analysis.
A new isochroman-4-one derivative from the peel of Musa sapientum L.and its total synthesis
Hai Qian , Wen Long Huang , Xiao Ming Wu , Hui Bin Zhang , Jin Pei Zhou , Wen Cai Ye
2007, 18(10): 1227-1230  doi: 10.1016/j.cclet.2007.07.020
[Abstract](194) [FullText HTML] [PDF 241KB](0)
Abstract:
A new isochroman-4-one, 7, 8-dihydroxy-3-methylisochroman-4-one was isolated from water soluble fraction of Musa sapientum L. Its structure was determined by spectroscopic evidences and its total synthesis has also been reported. The compound showed potent antihypertensive activity.
Two new C-glycosylflavones from Mimosa pudica
Ke Yuan , Jie Li Lu , An Jia , Jian Xin Zhu
2007, 18(10): 1231-1234  doi: 10.1016/j.cclet.2007.08.008
[Abstract](202) [FullText HTML] [PDF 228KB](0)
Abstract:
Two new C-glycosylflavones were isolated from the whole plant of Mimosa pudica, and their structures were determined as 6, 7, 3', 4'-tetrahydroxyl-8-C-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl flavone (1), 5, 7, 3', 4'-tetrahydroxy-8-C[β-D-apiose-(1→4)]-β-D-glycopyranosyl flavone (2). Their structures elucidated by chemical and spectroscopic analysis including IR, MS, 1D and 2D NMR spectra.
Three new C21 steroidal glycosides from the roots of Cynanchum inamoenum
Li Qin Wang , Jian Hua Wang , Yue Mao Shen , Jun Zhou
2007, 18(10): 1235-1238  doi: 10.1016/j.cclet.2007.07.026
[Abstract](191) [FullText HTML] [PDF 211KB](0)
Abstract:
Three new C21 steroidal glycosides named inamoside E (1), inamoside F (2) and inamoside G (3) were isolated from the roots of Cynanchum inamoenum (Maxim.) Loes. Their structures were determined by spectroscopic analysis, especially by 1D and 2D NMR experiments.
Furostanol saponins with inhibitory action against COX-2 production from Tupistra chinensis rhizomes
Kun Zou , Jun Zhi Wang , Jun Wu , Yuan Zhou , Chuang Liu , Fei Jun Dan , Ya Xiong Zhang , Jin Yang
2007, 18(10): 1239-1242  doi: 10.1016/j.cclet.2007.06.018
[Abstract](240) [FullText HTML] [PDF 212KB](0)
Abstract:
Two furostanol saponins were obtained from the n-butanol fraction of methanol extract from Tupistra chinensis rhizomes, a folk medicine of Shennongjia Forest District of Hubei Province. Their structures were determined as (25S)-26-O-(β-D-glucopyranosyl)-furost-1β, 3β, 22α, 26-tetrol-3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (1) and (25R)-26-O-(β-D-glucopyranosyl)-furost-lβ, 3β 22α, 26-tetrol 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (2), on basis of chemical and spectroscopic evidences. 1 and 2 displayed marked inhibitory action towards COX-2 production in macrophages of the rat abdomen induced by LPS at 20 μg/mL.
Three new diarylheptanoids and their antioxidant property
Chang Xin Zhou , Xiang Yi Zhang , Xiao Wu Dong , Qiao Feng Tao , Hui Dou , Rong Ping Zhang , Ke Xin Huang , Xiao Kun Li , Chang Xiang Chen , Su Zeng , Yu Zhao
2007, 18(10): 1243-1246  doi: 10.1016/j.cclet.2007.08.001
[Abstract](267) [FullText HTML] [PDF 258KB](0)
Abstract:
Three new diarylheptanoids, i. e., sodium(5S, 2E)-1, 7-bis(4-hydroxyphenyl)-1-hydroxy-2-hepten-5-sulfonate (1), sodium(5S, 2E)-1, 7-bis(4-hydroxyphenyl)-1-hydroxy-2-hepten-5-sulfonate (2) and 3, 5-diacetoxy-1-(3-methoxy-4, 5-dihydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)heptane (3) were isolated from the rhizomes of Zingiber officinale. The structures of the new compounds were elucidated on the basis of spectroscopic methods. The antioxidant activities of 3 were assayed by in vitro models involving DPPH free radicals and superoxide anion radicals.
Two new compounds from Zingiber officinale
Yu Zhao , Qiao Feng Tao , Rong Ping Zhang , Chang Xin Zhou , Hui Dou , Shu Yun Shi , Ye Cheng Xiao , Lian Li Sun , Su Zeng , Ke Xin Huang , Xiao Dong Zhang , Xiao Kun Li
2007, 18(10): 1247-1249  doi: 10.1016/j.cclet.2007.08.002
[Abstract](187) [FullText HTML] [PDF 226KB](0)
Abstract:
A new cyclic diarylheptanoid, 1, 5-epoxy-3-hydroxy-1-(3-methoxy-4, 5-dihydroxyphenyl)-7-(4-hydroxyphenyl)-heptane (1), as well as a new monoterpene, 10-O-β-D-glucopyranosyl-hydroxy cineole (2) were isolated from the rhizomes of Zingiber officinale. The structures of compounds 1 and 2 were established based on their spectral data. In addition, the antioxidant activities of these compounds were also measured.
Preparation of new hybrid organic/inorganic polymeric chiral stationary phases for ligand-exchange chromatography
Rui Juan Song , Yu Fu , Na Yao , Yuan De Long , Tian Bao Huang
2007, 18(10): 1250-1252  doi: 10.1016/j.cclet.2007.07.022
[Abstract](192) [FullText HTML] [PDF 268KB](0)
Abstract:
Three new hybrid organic/inorganic polymeric ligand-exchange chiral stationary phases were developed by radical chain transfer reaction and surface grafting on silica gel, and successfully used for the enantioseparations of DL-amino acids and DL-hydroxyl acids. The resolutions were achieved by using water containing 2.0×10-4 mol/L of CuAc2 as a mobile phase, column temperature of 40℃, flow rate of 1.0 mL/min and detection at UV 254 mn. The elution order of D-isomer before L-isomer was observed for all DL-amino acids resolved except DL-Pro.
Spectrometric study of α-methylene aromatic araminenone and aminoketone
Li Yuan Mou , Zi Yun Lin , Li Ya Zhu , Xiao Tian Liang
2007, 18(10): 1253-1255  doi: 10.1016/j.cclet.2007.07.019
[Abstract](195) [FullText HTML] [PDF 280KB](0)
Abstract:
Thirteen α-methylene aromatic araminenone and four α-methylene aromatic aminoketones were prepared by modified Mannich reaction. On the basis of isotopic labeling, a plausible way of cleavage was proposed for the formation of the M+-17 fragment peak in the MS of the α-methylene aromatic araminenone and aminoketones. The characteristic chemical shift of the olefinic protons in 1H NMR is also discussed.
Pure LiFePO4 with high energy density prepared by water quenching treatment
Xu Guang Gao , Guo Rong Hu , Zhong Dong Peng , Ke Du , Xin Rong Deng
2007, 18(10): 1256-1260  doi: 10.1016/j.cclet.2007.08.017
[Abstract](201) [FullText HTML] [PDF 766KB](0)
Abstract:
A compound "vacuum firing and water quenching" technique was presented in the synthesis of LiFePO4 cathode powder. The sample was prepared by heating the pre-decomposed precursor mixtures sealed in vacuum quartz-tube, followed by water quenching at the sintering temperature. The results indicate that using the "fast quenching" treatment can succeed in controlling overgrowth of the grain size of final product and improving its utilization ratio of active material. The sample synthesized by this technique has the high reversible discharge specific capacity and good cyclic electrochemical performance.
A novel Fe (OH)3/TiO2 nanoparticles and its high photocatalytic activity
Nan Wang , Li Hua Zhu , Jing Li , He Qing Tang
2007, 18(10): 1261-1264  doi: 10.1016/j.cclet.2007.08.020
[Abstract](188) [FullText HTML] [PDF 273KB](0)
Abstract:
A very simple and controllable approach was proposed to synthesize novel Fe(OH)3/TiO2 nanoparticles. Compared with neat TiO2, the Fe(OH)3/TiO2 increased the rate of the photocatalytic degradation of methyl orange at pH 6.0 by more than five times, showing photocatalytic activity as excellent as P25. This enhancing effect is mainly attributed to the ferric hydroxide deposits as the electron scavenger and the enriched surface hydroxyl groups.
Effect of surfactant structure on catalysis of microemulsion for photoisomerization of trans-stilbene
Xia Guo , Ling Lin , Rong Guo
2007, 18(10): 1265-1268  doi: 10.1016/j.cclet.2007.07.018
[Abstract](190) [FullText HTML] [PDF 227KB](0)
Abstract:
In this study, the photoisomerization of trans-stilbene was carried out in water in oil (W/O) microemulsions by using sodium dodecyl sulfate (SDS), dodecyl trimethyl ammonium bromide (DTAB) and cetyl trimethyl ammonium bromide (CTAB) as surfactant, respectively. The catalytic effect of microemulsion on this reaction is closely related to the structure of surfactanz. When there is no photosensitizer 9, 10-dicyanoanthracene (DCA), the surfactant with shorter hydrophobic chain is preferred, while in the presence of DCA, the surfactant with anionic polar group is preferred.
Synthesis and characterization of quaternized poly (phthalazinone ether sulfone ketone) for anion-exchange membrane
Xi Gao Jian , Chun Yan , Hua Min Zhang , Shou Hai Zhang , Cheng Liu , Ping Zhao
2007, 18(10): 1269-1272  doi: 10.1016/j.cclet.2007.08.022
[Abstract](221) [FullText HTML] [PDF 242KB](0)
Abstract:
Chloromethylated poly(phthalazinone ether sulfone ketone) (CMPPESK) was prepared from poly(phthalazinone ether sulfone ketone) (PPESK) using chloromethyl octyl ethers (CMOE) with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc) and chloroform. Quatemized poly(phthalazinone ether sulfone ketone) (QAPPESK) was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid (98%) and swollen in N, N-dimethylformamide (DMF). The vanadium redox flow battery (V-RFB) using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.
TiO2/polyaniline composites:An efficient photocatalyst for the degradation of methylene blue under natural light
Fang Wang , Shi Xiong Min
2007, 18(10): 1273-1277  doi: 10.1016/j.cclet.2007.08.010
[Abstract](191) [FullText HTML] [PDF 623KB](0)
Abstract:
Polyaniline (PAn) sensitized nanocrystalline TiO2 composites (TiO2/PAn) were successfully prepared and used as an efficient photocatalyst for the degradation of dye methylene blue (MB). The results showed that PAn was able to sensitize TiO2 efficiently and the composite photocatalyst could be activated by absorbing both the ultraviolet and visible light (λ:190~800 nm), whereas pure TiO2 absorbed ultraviolet light only (λ<380 nm). Under the irradiation of natural light, MB could be degraded more efficiently on the TiO2/PAn composites than on the TiO2. Furthermore, it could be easily separated from the solution by simple sedimentation.
The complexes of multiimidazole with copper (Ⅰ) display tyrosinase activity
Rong Xiao , Xiao Yu Su , Ru Gang Xie
2007, 18(10): 1278-1280  doi: 10.1016/j.cclet.2007.07.013
[Abstract](196) [FullText HTML] [PDF 246KB](0)
Abstract:
The six multiimidazole copper(Ⅰ) complexes are utilized to mimic tyrosinase. The main product is 3, 5-di-t-butylcatechol from o-hydroxylation of the substrate 2, 4-di-t-butylphenol. The highest yield of catechol is up to 82.2% and selectivity 94.8% by[Cu(Ⅰ)2(3b)(MeCN)2](ClO4)2 and O2 under mild conditions, which are found to be more efficient than that already reported.
Methylation of 2-methylnaphthalene with methanol to 2,6-dimethylnaphthalene over HZSM-5 modified by NH4F and SrO
Chen Zhang , Xin Wen Guo , Ya Nan Wang , Xiang Sheng Wang , Chun Shan Song
2007, 18(10): 1281-1284  doi: 10.1016/j.cclet.2007.07.025
[Abstract](172) [FullText HTML] [PDF 229KB](0)
Abstract:
The methylation of 2-methylnaphthalene (2-MN) into 2, 6-dimethylnaphthalene (2, 6-DMN) was investigated over the solid acid catalysts. The results show that HZSM-5 modified by NH4F has better catalytic performance than parent HZSM-5 due to the decrease in the acidity. When NH4F/HZSM-5 is further modified by SrO, its catalytic activity decreases due to the decrease in the total acid amount and acidic strength. As a result, the comprehensive modification of NH4F and SrO leads to the increase in the 2, 6-DMN selectivity (2, 6-DMN to DMN), up to 64.8% when 2-MN conversion is 10%. We calculated the ESP charge by density functional theory and the results show that the 6-position in 2-MN has higher ESP charge value than 7-position. The formation of 2, 6-DMN is favored energetically as compared to that for 2, 7-DMN. This suggests during the alkylation of 2-MN inside the ZSM-5 channel, the formation of 2, 6-DMN is favored electronically than that of 2, 7-DMN. Hence, lowering the acidity of catalyst is a key factor to obtain high selectivity of 2, 6-DMN.
Preparation of nanometer FeCuP alloy and its application in decomposition of PH3
Chang Xiu Han , Ji Li Ren , Xue Jiao Tang , Bao Gui Zhang
2007, 18(10): 1285-1288  doi: 10.1016/j.cclet.2007.08.005
[Abstract](203) [FullText HTML] [PDF 1015KB](1)
Abstract:
A new ternary Fe-based alloy catalyst FeCuP applied to decompose PH3 was prepared with low-cost material by chemical reduction deposition method. The properties of it were characterized by XRD, ICP and SEM. Its catalytic activity on the decomposition of PH3 and the decomposition conditions were studied. FeCuP alloy exhibits high thermal stabilities and high catalytic activity. Using it as catalyst, the decomposition temperature of phosphine decreases from over 800℃ to 400-500℃. The decomposition rate of phosphine achieved 100%.
The preparation and fluorescence properties of europium nanoparticles
Xi Bao Gao , Jiang Yu , Ning Li , Hong Yin Yin , Jing He Yang
2007, 18(10): 1289-1292  doi: 10.1016/j.cclet.2007.07.010
[Abstract](182) [FullText HTML] [PDF 912KB](0)
Abstract:
A new structured metallic nanomaterial of europium nanoparticle was prepared using tannic acid as the reductive agent, and nanoeuropium protein conjugates were synthesized by the method of lipoic acid modification on the surface of nanoparticle, which opens a new field of application of lanthanides in nanotechniques. Their properties were also characterized by UV-vis absorption spectroscopy, transmission electron microscopy (TEM), and fluorescence spectroscopy. The europium nanoparticle and its protein conjugates solution were stable and water-soluble. The fluorescence intensity of the composite europium nanoparticles was significantly increased in the presence of trace protein, and was linear proportional to the concentration of proteins under optimum conditions. According to this, a fluorimetric method for the determination of protein was developed in this paper.
Critical bubble radius in solvent sublation
Peng Yu Bi , Hui Ru Dong , Nan Nan Wang
2007, 18(10): 1293-1296  doi: 10.1016/j.cclet.2007.08.009
[Abstract](269) [FullText HTML] [PDF 457KB](0)
Abstract:
The complex compound of dithizone-Co(Ⅱ) was separated and concentrated from the aqueous phase to n-octanol by solvent sublation. From the analysis of the coalescence behavior of bubbles on water-organic interface, the conception of critical bubble radius was proposed, and the value of the critical bubble radius in the water-octanol system was obtained:1.196×10-3 m. The simulation of the mathematical model using CBR and experimental data is completed with perfect results, and the simulation of the mathematical model using CBR is very different with the classic one. The analytical results proved that the critical bubble radius should be adequately considered in mathematical model of solvent sublation.
A preliminary study of isopropyl alcohol matrix effect and correction in ICP-MS
Zhao Chu Hu , Shan Gao , Sheng Hong Hu , Yong Sheng Liu , Hai Hong Chen
2007, 18(10): 1297-1300  doi: 10.1016/j.cclet.2007.08.012
[Abstract](181) [FullText HTML] [PDF 327KB](1)
Abstract:
Isopropyl alcohol matrix effect was found to be element specific by using the defined matrix effect factor in ICP-MS, which could not be corrected by using the conventional internal reference method. Unlike the conventional internal reference method, the presented method allows for the analyte to behave differently from the internal reference under the influence of the matrix.
A combined electrochemical and DFT study of the lattice strain effect on the surface reactivity of Pd
You Gui Chen , Lin Zhuang , Jun Tao Lu
2007, 18(10): 1301-1304  doi: 10.1016/j.cclet.2007.08.006
[Abstract](192) [FullText HTML] [PDF 915KB](0)
Abstract:
We report a combined study of electrochemical experiments and ab initio calculations on tuning the surface reactivity of Pd via a compressive lattice strain achieved by employing nanoparticles of Pd-Cu alloys with a Pd-rich surface. Surface oxygen-containing species were used as the probing molecule for revealing the surface reactivity. Both density functional theory (DFT) calculations and experiments showed linear relationships, with very close slopes, between the adsorption strength of OHads and the Pd lattice constant. Not only is this work a successful realization of controllable modulation in the surface reactivity, but it also provides valuable information for the rational design of Pd-based catalysts for fuel cell applications.
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