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2007 Volume 18 Issue 10
2007, 18(10): 1163-1165
doi: 10.1016/j.cclet.2007.07.024
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.
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.
2007, 18(10): 1166-1168
doi: 10.1016/j.cclet.2007.08.021
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.
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.
2007, 18(10): 1169-1172
doi: 10.1016/j.cclet.2007.07.030
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.
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.
2007, 18(10): 1173-1175
doi: 10.1016/j.cclet.2007.07.023
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%.
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%.
2007, 18(10): 1176-1177
doi: 10.1016/j.cclet.2007.08.018
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.
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.
2007, 18(10): 1178-1181
doi: 10.1016/j.cclet.2007.08.014
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.
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.
2007, 18(10): 1182-1186
doi: 10.1016/j.cclet.2007.08.015
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.
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.
2007, 18(10): 1187-1190
doi: 10.1016/j.cclet.2007.08.013
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.
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.
2007, 18(10): 1191-1194
doi: 10.1016/j.cclet.2007.07.027
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.
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.
2007, 18(10): 1195-1198
doi: 10.1016/j.cclet.2007.07.017
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.
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.
2007, 18(10): 1199-1202
doi: 10.1016/j.cclet.2007.07.016
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.
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.
2007, 18(10): 1203-1204
doi: 10.1016/j.cclet.2007.08.007
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.
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.
2007, 18(10): 1205-1208
doi: 10.1016/j.cclet.2007.07.012
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 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.
2007, 18(10): 1209-1212
doi: 10.1016/j.cclet.2007.08.003
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.
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.
2007, 18(10): 1213-1217
doi: 10.1016/j.cclet.2007.08.011
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.
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.
2007, 18(10): 1218-1220
doi: 10.1016/j.cclet.2007.08.004
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.
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.
2007, 18(10): 1221-1223
doi: 10.1016/j.cclet.2007.08.019
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 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.
2007, 18(10): 1224-1226
doi: 10.1016/j.cclet.2007.08.016
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 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.
2007, 18(10): 1227-1230
doi: 10.1016/j.cclet.2007.07.020
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.
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.
2007, 18(10): 1231-1234
doi: 10.1016/j.cclet.2007.08.008
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.
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.
2007, 18(10): 1235-1238
doi: 10.1016/j.cclet.2007.07.026
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.
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
2007, 18(10): 1239-1242
doi: 10.1016/j.cclet.2007.06.018
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.
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.
2007, 18(10): 1243-1246
doi: 10.1016/j.cclet.2007.08.001
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.
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.
2007, 18(10): 1247-1249
doi: 10.1016/j.cclet.2007.08.002
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.
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.
2007, 18(10): 1250-1252
doi: 10.1016/j.cclet.2007.07.022
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.
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.
2007, 18(10): 1253-1255
doi: 10.1016/j.cclet.2007.07.019
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.
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.
2007, 18(10): 1256-1260
doi: 10.1016/j.cclet.2007.08.017
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 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.
2007, 18(10): 1261-1264
doi: 10.1016/j.cclet.2007.08.020
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.
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.
2007, 18(10): 1265-1268
doi: 10.1016/j.cclet.2007.07.018
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.
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.
2007, 18(10): 1269-1272
doi: 10.1016/j.cclet.2007.08.022
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.
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.
2007, 18(10): 1273-1277
doi: 10.1016/j.cclet.2007.08.010
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.
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.
2007, 18(10): 1278-1280
doi: 10.1016/j.cclet.2007.07.013
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.
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.
2007, 18(10): 1281-1284
doi: 10.1016/j.cclet.2007.07.025
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.
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.
2007, 18(10): 1285-1288
doi: 10.1016/j.cclet.2007.08.005
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%.
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%.
2007, 18(10): 1289-1292
doi: 10.1016/j.cclet.2007.07.010
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.
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.
2007, 18(10): 1293-1296
doi: 10.1016/j.cclet.2007.08.009
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.
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.
2007, 18(10): 1297-1300
doi: 10.1016/j.cclet.2007.08.012
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.
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.
2007, 18(10): 1301-1304
doi: 10.1016/j.cclet.2007.08.006
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.
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.
