2010 Volume 21 Issue 7

A rapid and efficient method for the synthesis of 14H-dibenzo [α.j] xanthenes, aryl-5H-dibenzo [b.i]xanthene-5,7,12,14-(13H)-tetraone and 1,8-dioxooctahydroxanthenes by acidic ionic liquid
Abbas Rahmati
2010, 21(7): 761-764  doi: 10.1016/j.cclet.2010.02.014
[Abstract](181) [FullText HTML] [PDF 252KB](0)
Abstract:
Various xanthenes have been synthesized by the condensation of β-naphthol, 2-hydroxynaphthalene-1,4-dione or dimedone with various aldehydes in the presence of trifluoroacetic acid as catalyst in 1,1,3,3-N,N,N',N'-tetramethylguanidinium trifluoroacetate (TMGT) ionic liquid within 1h at 75℃.
An efficient synthesis of ampicillin on magnetically separable immobilized penicillin G acylase
Ping Xue , Xiao Dan Song , Xue Rong Cao
2010, 21(7): 765-768  doi: 10.1016/j.cclet.2010.02.015
[Abstract](188) [FullText HTML] [PDF 817KB](0)
Abstract:
Penicillin G acylase (PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm, specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g. The 96.7% ampicillin yield with 1.60 of the synthesis/hydrolysis (S/H) ratio from 6-aminopenicillanic acid (6-APA) and D-(-)-alpha-phenylglycine methyl ester (D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol, where only 82.1% yield with 1,40 of the S/H ratio was obtained using the free PGA under the identical reaction conditions. The immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.
Synthesis, spectroscopic and electrochemical property of an unsymmetrical porphyrin and its Zn compound
Chang Fu Zhuang , Yu Jing Zhang , Ai Qing Xia , Wen Hui Lian , Yun Fang Wang , Ping Zhang , Tong Shun Shi
2010, 21(7): 769-773  doi: 10.1016/j.cclet.2010.03.037
[Abstract](186) [FullText HTML] [PDF 504KB](0)
Abstract:
In this article, a new 5-(p-maleicaminophenyl)-10,15,20-triphenylporphyrin (H2P) and relative zinc compound (ZnP) were synthesized and characterized by means of elemental analyses, UV-vis, IR, MS and 1H NMR spectroscopies. Furthermore, we have investigated the fluorescence spectroscopy of these compounds. The oxidation and reduction properties of the compounds were studied by the cyclic voltammetry, the oxidation-reduction potentials were obtained.
Simply air:Vanadium-catalyzed oxidative kinetic resolution of methyl o-chloromandelate by ambient air
Lu Yin , Xian Jia , Xing Shu Li , Albert S. C. Chan
2010, 21(7): 774-777  doi: 10.1016/j.cclet.2010.03.002
[Abstract](182) [FullText HTML] [PDF 262KB](0)
Abstract:
Vanadium-catalyzed oxidative kinetic resolution (OKR) of methyl o-chloromandelate 2a, key intermediate of the well-known oral antiplatelet agent (S)-clopidogrel, was achieved by ambient air for the first time. The air oxidation system, which was composed of vanadium and tridentate Schiff base ligands derived from amino alcohols and salicylaldehyde derivatives, afforded an efficient and economic approach to the target intermediate with high enantioselectivities (> 99% ee).
Highly efficient synthesis of 2,3-dihydroquinazolin-4 (1H)-ones catalyzed by heteropoly acids in water
YingXiao Zong , Yan Zhao , WenCai Luo , Xing Hai Yu , Jun Ke Wang , Yi Pan
2010, 21(7): 778-781  doi: 10.1016/j.cclet.2010.03.022
[Abstract](194) [FullText HTML] [PDF 223KB](0)
Abstract:
Heteropoly acids efficiently catalyzed the cyclocondensation reaction of anthranilamide with aldehydes in water at ambient temperature and afforded the corresponding 2,3-dihydro-4 (1H)-quinazolinones compounds in good to excellent yields. This method provides mild reaction conditions and clean reaction profiles, using a small quantity of catalyst and a simple workup procedure.
A convenient synthesis of quinazoline derivatives via cascade imino-Diels-Alder and oxidation reaction
Xue Ming Chen , Hui Wei , Lu Yin , Xing Shu Li
2010, 21(7): 782-786  doi: 10.1016/j.cclet.2010.03.003
[Abstract](193) [FullText HTML] [PDF 276KB](0)
Abstract:
Quinazoline derivatives were synthesized from α-iminoesters via a cascade imino-Diels-Alder and then oxidation reaction catalyzed with CuBr2. This method provided a new strategy for preparing quinazoline derivatives which may be useful in the synthesis of heterocyclic intermediates.
Photochemical reaction of magnesium tetraphenyl porphyrin with sulfur dioxide
Jian Bin Zhang , Chun Ping Li , Tian Rui Huo , Zhan Ying Liu , Li Hua Liu , Tong Zhang , Dong Yan Zhang , Xiong Hui Wei
2010, 21(7): 787-789  doi: 10.1016/j.cclet.2010.03.023
[Abstract](187) [FullText HTML] [PDF 188KB](0)
Abstract:
The photochemical reaction of magnesium tetraphenyl porphyrin (MgTPP) with sulfur dioxide (SO2) was investigated in dichloromethane (CH2Cl2) by steady-state fluorescence, UV-vis absorption, MS, and XRD spectroscopic techniques. These spectra showed that under irradiation MgTPP reacted with SO2 to form 1:1 molecular adduct at first step. During the process of keeping irradiation and maintaining the flow of SO2, SO2 was reduced into S2- by MgTPP and the results were detected using MS and XRD techniques. Understanding the photochemical reaction of MgTPP with SO2 is of key interest in elucidating fundamental photochemical reaction mechanisms associated with this class of chlorophyll in the presence of SO2.
P2O5 mediated rapid condensation of 2-aminothiophenol with aromatic aldehydes at ambient temperature
Santosh V. Nalage , Sidhanath V. Bhosale , Dattatry S. Bhosale , Wamanrao N. Jadhav
2010, 21(7): 790-793  doi: 10.1016/j.cclet.2010.03.006
[Abstract](199) [FullText HTML] [PDF 370KB](0)
Abstract:
2-Arylbenzothiazoles formed in good yields (65-90%) by the condensation of aminothiophenols with aromatic aldehydes using P2O5 at ambient temperature.
Carbamate synthesis from amines and dialkyl carbonate over inexpensive and clean acidic catalyst-Sulfamic acid
Bo Wang , Jing He , Run Cang Sun
2010, 21(7): 794-797  doi: 10.1016/j.cclet.2010.03.012
[Abstract](188) [FullText HTML] [PDF 338KB](0)
Abstract:
Sulfamic acid has been proved to be the most efficient and recyclable catalyst in carbamate synthesis from alkylamine and dialkyl carbonate. High selectivity, cost-efficiency and simple product separation were the advantageous features obtained in this process. Sulfamic acid could be reused several times and keep its initial activity in the recycle runs. In addition, sulfamic acid has also exhibited the potential catalytic ability for alkylation of aromatic amines.
Stereoselective synthesis and crystal structure of 4,6-O-benzylidene-N-octyl-D-allosamine hydrochloride
Fu Yi Zhang , Chun Li Wu , Cui Zhang , Hong Min Liu
2010, 21(7): 798-801  doi: 10.1016/j.cclet.2010.02.020
[Abstract](208) [FullText HTML] [PDF 305KB](0)
Abstract:
The building block of N-alkyl derivative of allosamidin (chitinase inhibitor), 4,6-O-benzylidene-N-octyl-D-allosamine hydro-chloride was stereoselectively synthesized in two steps under mild conditions. Nucleophilic addition of octylamine to 2-oxoglucopyranoside gave a ‘carbonyl group transfer’ product in 62% yield. Subsequent stereoselective reduction of newly formed C=O with NaBH4 produced title compound in 75% yield. X-ray diffraction analysis indicates the title compound adopts syn 1,2,3 stereochemistry and chair-chair conformation. The crystal structure is stabilized by hydrogen bonds.
Enantioselective hydrogenation of acetophenone by (1S, 2S)-DPEN-Ru (Ⅱ) Cl2 (PPh3)2 encapsulated in Al-MCM-41
Jian Hong Liu , Dong Liang , Bin Bin Fan , Rui Feng Li , Hua Chen
2010, 21(7): 802-806  doi: 10.1016/j.cclet.2010.03.011
[Abstract](203) [FullText HTML] [PDF 261KB](0)
Abstract:
A chiral ruthenium complex [(1S,2S)-DPEN]-RuCl2 (PPh3)2 (DPEN=1,2-diphenylethylenediamine, PPh3=triphenylphosph-ine) was encapsulated in the channel of Al-MCM-41 by electrostatic adsorption and 1,1-dichlorosilacyclobutane modification. The prepared heterogeneous catalyst showed the same catalytic activity and enantioselectivity as the corresponding homogeneous catalyst in the asymmetric hydrogenation of acetophenone, and could be reused at least seven times without significant loss of catalytic activity and enantioselectivity.
Novel synthesis of N-substituted-calix [4]azacrown derivatives
Zhi Qiang Shi , Ya Qing Feng , Shu Xian Meng
2010, 21(7): 807-809  doi: 10.1016/j.cclet.2010.02.023
[Abstract](190) [FullText HTML] [PDF 205KB](0)
Abstract:
A novel series of calix [4]azacrown derivatives with the reaction between calix [4]azacrown and the different fluorophore derivatives, which may be useful fluorescent receptors, have been synthesized and structurally characterized by IR, 1H NMR, 13C NMR and MS. From their analysis data, it was found those compounds adopted a cone conformation.
The design and synthesis of a novel organophosphorus compound containing the structure of both β-amino acid and β-aminophosphonate
Han Bing Teng
2010, 21(7): 810-812  doi: 10.1016/j.cclet.2010.03.035
[Abstract](206) [FullText HTML] [PDF 261KB](0)
Abstract:
A novel organophosphorus compound containing the structure of both β-amino acid and B-aminophosphonate is designed and synthesized. Arbuzov reaction with P(OEt)3, the N-Boc protected iodide 3 cannot provide the desired product but 2-oxazolidinone 4 because of the neighboring-group participation of the Boc moiety.To avoid the intramolecular participation of the carbamates, the Ts protecting group is employed and the Ts-protected iodide 5 affords the target product successfully.
Synthesis of bisabolane sesquiterpenes:A Johnson-Claisen rearrangement approach
Zhen Ting Du , Hong Rui Yu , Yan Xu , Yong Li , An Pai Li
2010, 21(7): 813-815  doi: 10.1016/j.cclet.2010.02.024
[Abstract](179) [FullText HTML] [PDF 210KB](0)
Abstract:
sSeveral bisabolane sesquiterpenes, (±)-curcumene, (±)-curcuphenol, (±)-curcudiol and (±)-curcuhydroquinone, have been synthesized in racemic form and fully characterized. The salient characteristic of our approach is that a Johnson-Claisen arrangement was involved as a key step.
A new phenanthraquinone from the roots of Peucedanum praeruptorum
Cun Zhang , Li Li , Yong Qing Xiao , Wen Li , Xiao Jie Yin , Guo Fang Tian , Dong Dong Chen , Yun Wang
2010, 21(7): 816-817  doi: 10.1016/j.cclet.2010.03.020
[Abstract](189) [FullText HTML] [PDF 214KB](0)
Abstract:
A new compound, 9,10-dihydrophenanthrinic acid, 9,10-dione-3,4-methylenedioxy-8-methoxy (1) was isolated from the roots of Peucedanum praeruptorum Dunn on the basis of spectral evidences.
Two new chalcones from Fordia cauliflora
Zhi Yuan Liang , Xiao Sheng Yang , Ye Wang , Xiao Jiang Hao , Qian Yun Sun
2010, 21(7): 818-820  doi: 10.1016/j.cclet.2010.03.021
[Abstract](183) [FullText HTML] [PDF 217KB](1)
Abstract:
Two new chalcones, β,2',4',5'-tetramethoxychalcone 1, and β,2',5'-trimethoxyfurano [4",5":3',4']-chalcone 2 were obtained from an ethyl acetate-soluble fraction of ethanol extract of the stem of Fordia cauliflora. Their chemical structures were determined by analysis of spectroscopic evidences.
A new alkylene dihydrofuran glycoside with antioxidation activity from the root bark of Morus alba L.
Wei Fu , Yong Fang Lei , Ya Ling Cai , Dao Nian Zhou , Jin Lan Ruan
2010, 21(7): 821-823  doi: 10.1016/j.cclet.2010.02.016
[Abstract](192) [FullText HTML] [PDF 230KB](1)
Abstract:
A new alkylene dihydrofuran glycoside (1) was isolated from the root bark of Morus alba L., along with moracin M-3'-O-β-D-glucopyranoside (2), and moracin M-6,3'-di-O-β-D-glucopyranoside (3). Compound 1 was identified as 2-methylene-3-methoxy-2, 5-dihydrofuran-4-O-β-D-glucopyranoside on the basis of chemical and spectroscopic data including ID and 2D NMR spectral analysis. In addition, the antioxidant activity of 1 was evaluated using the l,l-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The IC50 values were 2.49 and 0.45 mg/mL, respectively.
Three new aspochalasin derivatives from the marine-derived fungus Spicaria elegans
Zhen Jian Lin , Tian Jiao Zhu , Li Chen , Qian Qun Gu
2010, 21(7): 824-826  doi: 10.1016/j.cclet.2010.02.019
[Abstract](183) [FullText HTML] [PDF 212KB](0)
Abstract:
Three new aspochalsins (R-T) (1-3) were isolated from the marine-derived fungus Spicaria elegans. Their structures were elucidated on the basis of comprehensive spectral analysis including 1D and 2D NMR techniques, and HR-ESI-MS.
Two new terpenes from Tripterygium wilfordii
Bo Le Li , Qian Shen , Mei Na Jin , Hong Quan Duan
2010, 21(7): 827-829  doi: 10.1016/j.cclet.2010.03.007
[Abstract](192) [FullText HTML] [PDF 236KB](1)
Abstract:
Two new terpenes,wilfornine H (1)and triptobenzene Q (2)were isolated from Tripterygium wilfordii,as well as 11 terpenes.Their structures were elucidated by spectroscopic methods.Compounds 5,9-13 shewed significant immunosuppressive activities.
Three new sesquiterpene alkaloids from the root of Tripterygium wilfordii
Chun Min Wu , Lin Mei Zhou , Yi Feng Chai , Yu Tian Wu , Guo Rong Fan
2010, 21(7): 830-833  doi: 10.1016/j.cclet.2010.02.021
[Abstract](185) [FullText HTML] [PDF 211KB](1)
Abstract:
Three new sesquiterpene alkaloids,1-desaeetylwilforgine (1),1-desaeetylwilforine (2),and 9'-hydroxy-2-nicotinoylwilforine (3)were isolated from the roots of Tripterygium wilfordii Hook f.,along with six known alkaloids.Their structures were established on the basis of spectral analysis.
A new derivative of triterpene with anti-melanoma B16 activity from Conyza canadensis
Ming Ming Yan , Ting You Li , Da Qing Zhao , Shuai Shao , Sheng Nan Bi
2010, 21(7): 834-837  doi: 10.1016/j.cclet.2010.02.022
[Abstract](195) [FullText HTML] [PDF 247KB](0)
Abstract:
A new derivative of triterpene named Erigeronol 1 was isolated from the EtOH extract of the aerial part of Conyza canadensis together with 15 known compounds for the first time from this plant.The structure of Erigeronol 1 was elucidated as 3-O-(hydroxyacetyl)-23,28-dihydroxy-β-amyrin by hydrolysis and spectroscopic analysis.Erigeronol 1 showed potent cytotoxic activity with IC50 value of 7.77±0.47 μg/mL against melanoma B16 determined by the 3-(4,5-dimethylthiazo-2-yl)-2,5-dipbenyltetrazolium bromide(MTT)method.
New limonoids from the fruits of Melia toosendan
Qiong Zhang , Jing Yu Liang , Qing Shan Li , Zhi Da Min
2010, 21(7): 838-841  doi: 10.1016/j.cclet.2010.02.018
[Abstract](187) [FullText HTML] [PDF 223KB](1)
Abstract:
Two new limonoids,1α-tigloyloxy-3α-acetoxyl-7α-hydroxyl-12α-ethoxyl nimbolinin (1)and 1α-benzoyloxy-3α-acetoxyl-7α-hydroxyl-12α-ethoxyl nimbolinin (2),were isolated from the fruits of Melia toosendan.Their structures were established on the basis of various NMR spectroscopic analyses,including 2D-NMR techniques (HSQC,HMBC,NOESY)and HR-ESI-MS.
Three antibacterial naphthoquinone analogues from cultured mycobiont of lichen Astrothelium sp
Li Yan Sun , Zhen Liang Liu , Tao Zhang , Shu Bin Niu , Zun Tian Zhao
2010, 21(7): 842-845  doi: 10.1016/j.cclet.2010.03.024
[Abstract](181) [FullText HTML] [PDF 278KB](0)
Abstract:
A new naphthoquinone compound named 7-hydroxyl-8-methoxyltrypethelone 3 together with two known compounds trypethelone 1 and trypethelone methyl ether 2 was isolated from cultured mycobiunt of Astrothelium sp.The structures were elucidated by 1D and 2D NMR spectroscopic analysis as well as comparison with those reported in literatures.Compound 1 displayed significant antibacterial activity against Bacillus subtilis (ATCC 6633),and showed modest antibacterial activity against Staphylococcus aureus col (MRSA) (CGMCC 1.2465),while compounds 2 and 3 showed modest antibacterial activity against Enterococcus faecalis 850E (CGMCC 1.2135)and S.aureus col (MRSA) (CGMCC 1.2465).
Two new 5α-adynerin-type compounds from Parepigynum funingense
Yan Hua , Hai Yang Liu , Wei Ni , Chang Xiang Chen
2010, 21(7): 846-849  doi: 10.1016/j.cclet.2010.03.034
[Abstract](182) [FullText HTML] [PDF 214KB](1)
Abstract:
A new 5α-adynerin-type cardenolide,named funingenoside U (1),together with its aglycone,(17R)-3β-hydroxy-4β-acetoxy-8,14β-epoxy-5α-card-20 (22)-enolide,was isolated from the roots of Parepigynum funingense.Their structures were established on the basis of spectral (MS,1D and 2D NMR) measurements and chemical evidences.
A new polyacetylene glycoside from the rhizomes of Atractylodes lancea
Ying Ji , Xu Feng , Chao Cheng Xiao , Yun Fa Dong , Qi Zhi Wang , Ming Wang , You Yi Zhao
2010, 21(7): 850-852  doi: 10.1016/j.cclet.2010.03.026
[Abstract](192) [FullText HTML] [PDF 211KB](1)
Abstract:
A new polyacetylene glycoside, (1,3Z,11E)-tridecatriene-7,9-diyne-5-hydroxyl-6-O-β-D-glucopyranoside,was isolated from the rhizomes of Atractylodes lancea (Thunb.)DC.Its structure was elucidated on the basis of spectral analysis.
1H NMR analysis of the tolylene-2,4-diisocyanate-methanol reaction
Peng Fei Yang , Yong De Han , Tian Duo Li , Jun Ying Li
2010, 21(7): 853-855  doi: 10.1016/j.cclet.2010.02.017
[Abstract](186) [FullText HTML] [PDF 255KB](0)
Abstract:
Tolylene-2,4-diisocyanate (2,4-TDI)1 reacts with methanol through two simultaneous paths in the polyurethane reaction,which involve two different intermediates-tolylene-4-caxbamatic-2-isocyanate 2 and tolylene-2-carbamatic-4-isocyanate 3,and the final product is tolylene-2,4-dicarbamate 4.The-CH3 chemical shifts in benzene ring in compounds 1,2,3 and 4 can be easily tested and well distinguished,through which those four compounds are quantified and their kinetics are investigated.It shows that four rate constants for the tolylene-2,4-diisocyanate-methanol reaction in CCl4 at 50℃ are k1=9.6×10-2h-2mol-2min-1,k2=1.4×10-2h-2mol-2min-l,k3=4.0×10-3h-2mol-2min-1,k4=1.4×10-3h-2mol-2min-1.(k1 is the reaction rate constant from compounds 1 to 2; k2 is the reaction rate constant from compounds 1 to 3; k3 is the reaction rate constant from compounds 3 to 4; k4 is the reaction rate constant from compounds 2 to 4).
Chemiluminescence determination of 20 amino acids and the mechanism study
Yan Ming Liu , Zhuan Li Liu
2010, 21(7): 856-859  doi: 10.1016/j.cclet.2010.01.025
[Abstract](178) [FullText HTML] [PDF 294KB](0)
Abstract:
It was found that 20 amino acids could inhibit the intensity of the luminol-H2O2-CuSO4 chemiluminescence system.Using this character,a rapid and sensitive method for the determination of 20 amino acids was developed with flow injection coupled with chemiluminescence detection.Under the optimal conditions,the detection limits of 20 amino acids were in the range of 4.5×10-7-4.3×10-10 mol/L,and the relative standard deviations were less than 3.2%.The proposed method was successfully applied to drug analysis.The possible mechanism was also discussed.
High performance liquid chromatographic separation of clausenamide enantiomers with chiral-AGP stationary phase
Yan Wang , Qing Qiang Yao , Mu Zou Wang
2010, 21(7): 860-863  doi: 10.1016/j.cclet.2010.01.024
[Abstract](183) [FullText HTML] [PDF 350KB](0)
Abstract:
A method of high performance liquid chromatographic separation of clausenamide enantiomers with chiral-AGP (α1-acid glycoprotein)stationary phases has been established.The absolute configurations of (-)clausenamide and (+)clausenamide are 3S,4R,5R,6S and 3R,4S,5S,6R,respectively.The present method has been used to analyze the (-) clausenamide and (+) clausenamide and its analogues such as the major metabolite and synthetic derivatives of clansenamide.
Fabrication of triple-shelled hollow spheres with optical properties via RAFT polymerization
Li Ping Wang , Li Min Zhao , Wen Zhi Li , Rui Qing Chu , Long Tan , Xiu Xiu Zhao , Gang Wang
2010, 21(7): 864-867  doi: 10.1016/j.cclet.2010.01.039
[Abstract](187) [FullText HTML] [PDF 923KB](0)
Abstract:
The triple-shelled hollow spheres with optical properties were prepared via reversible addition-fragmentation chain transfer (RAFT)polymerization.After removal the core templates of the poly (styrene),the hollow silica spheres were obtained.The coating process of poly (methyl methacrylate) (PMMA)on the hollow silica spheres surface via surface RAFT polymerization was performed subsequently.The polymers coated on the hollow spheres surfaces were end-functionalized by trithiocarbonate,and they were used as RAFT agent to proceed the chain extension polymerization using Tb complex as monomer.The samples were characterized by FT-IR,SEM and luminescence spectroscopy respectively.The results indicated that the triple-shelled hollow spheres had been prepared successfully and the average diameter of the hollow core was about 1 μm.
Synthesis of benzoxazine-based phenolic resin containing furan groups
Sheng Fang Li
2010, 21(7): 868-871  doi: 10.1016/j.cclet.2010.01.007
[Abstract](183) [FullText HTML] [PDF 256KB](0)
Abstract:
A novel benzoxazine-based phenolic resin containing furan groups (PFB)was synthesized via simple two-step reactions and the structure of PFB was confirmed by FTIR and 1H NMR spectra.Differential scanning calorimetry (DSC)showed that the polybenzoxazine cured from PFB had good heat resistance and lower polymerization temperature compared with that of benzoxazine-hased phenolic resins.
Ionic liquid-assisted synthesis of silver nanorods by polyol reduction
Hong Ying Wang , Yan An Gao , Ming Wei Zhao , Li Qiang Zheng
2010, 21(7): 872-875  doi: 10.1016/j.cclet.2010.01.036
[Abstract](187) [FullText HTML] [PDF 2975KB](0)
Abstract:
Silver nanorods have been successfully synthesized in large scale by the ethylene glycol (EG) reduction in the presence of ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) and polyvinyl-pyrrolidone (PVP).The silver nanorods were characterized by scanning electron microscopy (SEM),high-resolution transmission electron microscopy (HRTEM),transmission electron microscopy (TEM),electron energy disperse spectroscopy (EDS) and UV-vis spectroscopy.The results showed that the uniform silver nanorods have an average diameter of about 100 nm and the aspect ratio from 15 to 20.IL,bmimBF4 may play a role of capping agent together with PVP in the formation of silver nanorods.On the other hand,bmimBF4 may accelerate nucleation and improve the stability of the resulting Ag nanorods due to the low interface tension of IL.
Layer-by-layer electrostatic selfassembly of anionic and cationic carbon nanotubes
Yu Jun Qin , You You Wang , Ming Xue Tang , Zhi Xin Guo
2010, 21(7): 876-879  doi: 10.1016/j.cclet.2010.02.003
[Abstract](181) [FullText HTML] [PDF 1875KB](0)
Abstract:
The layer-by-layer (LBL) selfassembly of anionic and cationic multi-walled carbon nanotubes (MWNTs) through electrostatic interaction has been carried out to fabricate all-MWNT multilayer films.The alternate uniform assembly of anionic and cationic MWNTs was investigated by UV-vis spectroscopy.Scanning electron microscopy (SEM) images displayed the growth of the MWNT films.
Surfactant-free oil/water and bicontinuous microemulsion composed of benzene,ethanol and water
Fei Song , Jie Xu , Wan Guo Hou
2010, 21(7): 880-883  doi: 10.1016/j.cclet.2010.01.029
[Abstract](183) [FullText HTML] [PDF 866KB](0)
Abstract:
Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel surfactantfree microemulsion (denoted as SFME) composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water (O/W) microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy (FF-TEM) observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.
Preparation of polypyrrole/polyvinylalcohol (PPy/PVA)composite foam electrode material
Xin Yi Wang , Li Ping Heng , Nai Liang Yang , Qiang Xie , Jin Zhai
2010, 21(7): 884-887  doi: 10.1016/j.cclet.2010.01.005
[Abstract](181) [FullText HTML] [PDF 691KB](0)
Abstract:
Polypyrrole/polyvinylalcohol (PPy/PVA) foam was prepared by direct foam polymerization in water and then it was coated on the indium-tin oxide transparent conductive glass (ITO) to form conventional three-electrode cell.FTIR and UV-vis spectra were adopted to characterize the molecular structure and the absorption spectra of foam material,respectively.The porous structure of PPy/PVA foams and their photoelectric conversion behaviors were studied.The dimension of the pores is bigger than 100 μm in diameter.Compared with the smooth film,the Voc and Isc of the foam film enhanced by 1.58-fold and 5.59-fold,respectively.
Address:Zhongguancun North First Street 2,100190 Beijing, PR China Tel: +86-010-82449177-888
Powered By info@rhhz.net