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2007 Volume 18 Issue 2
2007, 18(2): 121-123
doi: 10.1016/j.cclet.2006.12.004
Abstract:
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.
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.
2007, 18(2): 124-126
doi: 10.1016/j.cclet.2006.12.001
Abstract:
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.
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.
2007, 18(2): 127-129
doi: 10.1016/j.cclet.2006.12.003
Abstract:
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.
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.
2007, 18(2): 130-132
doi: 10.1016/j.cclet.2006.12.010
Abstract:
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.
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.
2007, 18(2): 133-136
doi: 10.1016/j.cclet.2006.12.005
Abstract:
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.
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.
2007, 18(2): 137-140
doi: 10.1016/j.cclet.2006.12.006
Abstract:
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).
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).
2007, 18(2): 141-144
doi: 10.1016/j.cclet.2006.12.021
Abstract:
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.
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.
2007, 18(2): 145-148
doi: 10.1016/j.cclet.2006.12.023
Abstract:
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.
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.
2007, 18(2): 149-151
doi: 10.1016/j.cclet.2006.12.014
Abstract:
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.
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.
2007, 18(2): 152-154
doi: 10.1016/j.cclet.2006.12.007
Abstract:
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.
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.
2007, 18(2): 155-157
doi: 10.1016/j.cclet.2006.12.019
Abstract:
Two new phenylethanoid glycosides were isolated from the roots of Phlomis umbrosa. Their structures were elucidated by spectroscopic methods.
Two new phenylethanoid glycosides were isolated from the roots of Phlomis umbrosa. Their structures were elucidated by spectroscopic methods.
2007, 18(2): 158-160
doi: 10.1016/j.cclet.2006.12.031
Abstract:
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.
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.
2007, 18(2): 161-164
doi: 10.1016/j.cclet.2006.12.027
Abstract:
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.
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.
2007, 18(2): 165-167
doi: 10.1016/j.cclet.2006.12.020
Abstract:
Microbial transformation of nigranoic acid by Caryospora carllicarpa YMF1.01026 afforded the new derivative 6β-hydroxynigranoic acid. Its structure was elucidated by spectroscopic methods.
Microbial transformation of nigranoic acid by Caryospora carllicarpa YMF1.01026 afforded the new derivative 6β-hydroxynigranoic acid. Its structure was elucidated by spectroscopic methods.
2007, 18(2): 168-170
doi: 10.1016/j.cclet.2006.12.011
Abstract:
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.
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.
2007, 18(2): 171-174
doi: 10.1016/j.cclet.2006.12.009
Abstract:
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.
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.
2007, 18(2): 175-177
doi: 10.1016/j.cclet.2006.12.037
Abstract:
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.
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.
2007, 18(2): 178-180
doi: 10.1016/j.cclet.2006.12.043
Abstract:
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.
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.
2007, 18(2): 181-184
doi: 10.1016/j.cclet.2006.12.042
Abstract:
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.
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.
2007, 18(2): 185-188
doi: 10.1016/j.cclet.2006.12.038
Abstract:
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.
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.
2007, 18(2): 189-191
doi: 10.1016/j.cclet.2006.12.034
Abstract:
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.
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.
2007, 18(2): 192-194
doi: 10.1016/j.cclet.2006.12.035
Abstract:
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.
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.
2007, 18(2): 195-197
doi: 10.1016/j.cclet.2006.12.016
Abstract:
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.
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.
2007, 18(2): 198-200
doi: 10.1016/j.cclet.2006.12.017
Abstract:
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.
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.
2007, 18(2): 201-204
doi: 10.1016/j.cclet.2006.12.022
Abstract:
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%.
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%.
2007, 18(2): 205-208
doi: 10.1016/j.cclet.2006.12.012
Abstract:
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.
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.
2007, 18(2): 209-212
doi: 10.1016/j.cclet.2006.12.002
Abstract:
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.
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.
2007, 18(2): 213-216
doi: 10.1016/j.cclet.2006.12.024
Abstract:
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.
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.
2007, 18(2): 217-220
doi: 10.1016/j.cclet.2006.12.030
Abstract:
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.
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.
2007, 18(2): 221-224
doi: 10.1016/j.cclet.2006.12.036
Abstract:
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.
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.
2007, 18(2): 225-228
doi: 10.1016/j.cclet.2006.12.040
Abstract:
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.
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.
2007, 18(2): 229-232
doi: 10.1016/j.cclet.2006.12.013
Abstract:
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.
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.
2007, 18(2): 233-236
doi: 10.1016/j.cclet.2006.12.032
Abstract:
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.
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.
2007, 18(2): 237-240
doi: 10.1016/j.cclet.2006.12.041
Abstract:
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.
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.
2007, 18(2): 241-243
doi: 10.1016/j.cclet.2006.12.008
Abstract:
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.
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.
2007, 18(2): 244-246
doi: 10.1016/j.cclet.2006.12.039
Abstract:
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.
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.
