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2007 Volume 18 Issue 11
2007, 18(11): 1305-1308
doi: 10.1016/j.cclet.2007.09.022
Abstract:
Sulfanilic acid has been found to be an efficient catalyst for the synthesis of 1, 5-benzodiazepines from o-phenylenediamine and ketones. This method is simple, effective and environmentally friendly and gives better yields.
Sulfanilic acid has been found to be an efficient catalyst for the synthesis of 1, 5-benzodiazepines from o-phenylenediamine and ketones. This method is simple, effective and environmentally friendly and gives better yields.
2007, 18(11): 1309-1312
doi: 10.1016/j.cclet.2007.09.008
Abstract:
Oxalic acid was found to be an efficient catalyst for Pechmann condensation, which includes the reaction between phenols and β-keto esters leading to formation of coumarin derivatives. The advantages of present methods are the use of cheap and easy available catalyst, solvent-free reaction conditions, better yields and shorter reaction time.
Oxalic acid was found to be an efficient catalyst for Pechmann condensation, which includes the reaction between phenols and β-keto esters leading to formation of coumarin derivatives. The advantages of present methods are the use of cheap and easy available catalyst, solvent-free reaction conditions, better yields and shorter reaction time.
2007, 18(11): 1313-1315
doi: 10.1016/j.cclet.2007.09.020
Abstract:
A novel and simple procedure for synthesis of azanucleoside by Mitsunobu reaction between N-(p-nitrobenzyloxycarbonyl)-trans-4-hydroxy-D-proline methyl ester obtained from trans-4-hydroxy-L-proline after six-step reaction and 2-fluoro-6-azidopurine is described, and azanucleoside is fluorinated by new fluridizer 2, 2-difluoro-1, 3-dimethylimidazolidine (DFI). All reactions could be carried out under mild condition.
A novel and simple procedure for synthesis of azanucleoside by Mitsunobu reaction between N-(p-nitrobenzyloxycarbonyl)-trans-4-hydroxy-D-proline methyl ester obtained from trans-4-hydroxy-L-proline after six-step reaction and 2-fluoro-6-azidopurine is described, and azanucleoside is fluorinated by new fluridizer 2, 2-difluoro-1, 3-dimethylimidazolidine (DFI). All reactions could be carried out under mild condition.
2007, 18(11): 1316-1318
doi: 10.1016/j.cclet.2007.09.023
Abstract:
The biotransformation of bufalin by cell suspension cultures of Platycodon grandiflorus was investigated and two new biotransformed products were obtained, which was 3-epi-telocinobufagin and 3-epi-bufalin-3-O-β-D-glucoside.
The biotransformation of bufalin by cell suspension cultures of Platycodon grandiflorus was investigated and two new biotransformed products were obtained, which was 3-epi-telocinobufagin and 3-epi-bufalin-3-O-β-D-glucoside.
2007, 18(11): 1319-1322
doi: 10.1016/j.cclet.2007.09.032
Abstract:
A series of new vinylated 5, 10, 15, 20-tetraphenylporphyrins have been synthesized and characterized by 1H NMR, MS, UV-vis and fluorescence studies. Following selective excitation of the porphyrin compounds with UV light, the energy is transferred to the porphyrin core and reemitted as red light. In comparison to tetraphenylporphyrin (TPP), the luminescence properties are markedly improved.
A series of new vinylated 5, 10, 15, 20-tetraphenylporphyrins have been synthesized and characterized by 1H NMR, MS, UV-vis and fluorescence studies. Following selective excitation of the porphyrin compounds with UV light, the energy is transferred to the porphyrin core and reemitted as red light. In comparison to tetraphenylporphyrin (TPP), the luminescence properties are markedly improved.
2007, 18(11): 1323-1326
doi: 10.1016/j.cclet.2007.09.011
Abstract:
Protein tyrosine phosphatase 1B (PTP1B) has received considerable attention from the drug industry as a potential treatment fordiabetes mellitus. Mangiferin has been reported to possess significant antidiabetic activity. Based on the previous study, eight new mangiferin derivates were synthesized and evaluated for their PTP1B inhibitory activity. Some of them displayed good inhibitory activity on PTP1B.
Protein tyrosine phosphatase 1B (PTP1B) has received considerable attention from the drug industry as a potential treatment fordiabetes mellitus. Mangiferin has been reported to possess significant antidiabetic activity. Based on the previous study, eight new mangiferin derivates were synthesized and evaluated for their PTP1B inhibitory activity. Some of them displayed good inhibitory activity on PTP1B.
2007, 18(11): 1327-1330
doi: 10.1016/j.cclet.2007.09.004
Abstract:
Microwave-assisted synthesis of new 2-arylpyrimido[4', 5':4, 5]thiazolo[3, 2-a]benzimidazol-4 (3H)-ones from 3-aminothiazolo[3, 2-a]benzimidazol-2-carboxamide and aroyl halides in solvent-free condition is described. In comparison with classical conditions the reactions are faster and the yields are higher under microwave irradiation.
Microwave-assisted synthesis of new 2-arylpyrimido[4', 5':4, 5]thiazolo[3, 2-a]benzimidazol-4 (3H)-ones from 3-aminothiazolo[3, 2-a]benzimidazol-2-carboxamide and aroyl halides in solvent-free condition is described. In comparison with classical conditions the reactions are faster and the yields are higher under microwave irradiation.
2007, 18(11): 1331-1334
doi: 10.1016/j.cclet.2007.09.012
Abstract:
In view of the property of porphyrin's accumulation selectively in tumor, the ftorafur was modified by binding a porphyrin block to improve its tumor targeting and reduce its side effects. These novel porphyrin derivatives and metal compounds were synthesized under mild conditions with satisfactory yield, and the constructions of all these new compounds were characterized by UV, IR, MS, 1H NMR spectra and elementary analysis. Their anticancer activities were evaluated by MTT assay; the results indicated that the anticancer activities of compounds 4a-c were twice as high as that of ftorafur.
In view of the property of porphyrin's accumulation selectively in tumor, the ftorafur was modified by binding a porphyrin block to improve its tumor targeting and reduce its side effects. These novel porphyrin derivatives and metal compounds were synthesized under mild conditions with satisfactory yield, and the constructions of all these new compounds were characterized by UV, IR, MS, 1H NMR spectra and elementary analysis. Their anticancer activities were evaluated by MTT assay; the results indicated that the anticancer activities of compounds 4a-c were twice as high as that of ftorafur.
2007, 18(11): 1335-1338
doi: 10.1016/j.cclet.2007.09.014
Abstract:
A series of heterocyclic acid esters of camptothecins as new compounds had been synthesized by acylation method, their in vitro and in vivo antitumor activities were evaluated. The cytotoxic results showed that 6 possessed the best efficacy on six human cancer cell lines in the six classes of CPTs' derivatives. In vivo testing results indicated that 9 had better antitumor activity against mouse liver carcinoma H22 than topotecan.
A series of heterocyclic acid esters of camptothecins as new compounds had been synthesized by acylation method, their in vitro and in vivo antitumor activities were evaluated. The cytotoxic results showed that 6 possessed the best efficacy on six human cancer cell lines in the six classes of CPTs' derivatives. In vivo testing results indicated that 9 had better antitumor activity against mouse liver carcinoma H22 than topotecan.
2007, 18(11): 1339-1341
doi: 10.1016/j.cclet.2007.09.002
Abstract:
The hydroxyl group of carbocyclic nucleosides was inversed when the compounds were treated with Me3SiCl, KCN and a catalytic amount of NaI in DMF/CH3CN.
The hydroxyl group of carbocyclic nucleosides was inversed when the compounds were treated with Me3SiCl, KCN and a catalytic amount of NaI in DMF/CH3CN.
2007, 18(11): 1342-1346
doi: 10.1016/j.cclet.2007.09.035
Abstract:
A novel oxadiazole-based copolymer has been successfully synthesized through the palladium-catalyzed cross-coupling polycondensation method. The copolymer P is soluble in common organic solvents. Its structure has characterized by 1H NMR, 13C NMR, gel permeation chromatagraphy (GPC), UV-vis absorbance (Abs) and photoluniminescence (PL) spectroscopy, and cyclic voltammetry (CV). Investigation of its optical properties revealed that it is yellow emitting material, and the electrochemical analysis showed that P was well suited poly (2, 5-dioctyloxy-p-phenylenevinylene) (PDOCPV) for photovoltaic devices, so the copolymer P is able to act as an electron acceptor in combination with PDOCPVas the electron donor to quench photoluminescence of the copolymer in the blend, indicative of the efficient photoinduced electron transfer from the PDOCPV to the P.
A novel oxadiazole-based copolymer has been successfully synthesized through the palladium-catalyzed cross-coupling polycondensation method. The copolymer P is soluble in common organic solvents. Its structure has characterized by 1H NMR, 13C NMR, gel permeation chromatagraphy (GPC), UV-vis absorbance (Abs) and photoluniminescence (PL) spectroscopy, and cyclic voltammetry (CV). Investigation of its optical properties revealed that it is yellow emitting material, and the electrochemical analysis showed that P was well suited poly (2, 5-dioctyloxy-p-phenylenevinylene) (PDOCPV) for photovoltaic devices, so the copolymer P is able to act as an electron acceptor in combination with PDOCPVas the electron donor to quench photoluminescence of the copolymer in the blend, indicative of the efficient photoinduced electron transfer from the PDOCPV to the P.
2007, 18(11): 1347-1350
doi: 10.1016/j.cclet.2007.09.029
Abstract:
Four novel organogermanium sesquioxides with anthraquinone or naphthalene moiety were synthesized. The structures were characterized by IR, NMR and elemental analysis, and their cytotoxicities were evaluated against human chronic myeloid leukemia K562 cell lines. The cytotoxicity could be improved by the introduction of planar aromatic chromophore moiety to the parent compound, Ge-132.
Four novel organogermanium sesquioxides with anthraquinone or naphthalene moiety were synthesized. The structures were characterized by IR, NMR and elemental analysis, and their cytotoxicities were evaluated against human chronic myeloid leukemia K562 cell lines. The cytotoxicity could be improved by the introduction of planar aromatic chromophore moiety to the parent compound, Ge-132.
2007, 18(11): 1351-1352
doi: 10.1016/j.cclet.2007.09.036
Abstract:
Three new 1, 3-bis (phenylethynyl) disilazanes were synthesized from the reaction of 1, 3-dichlorodisilazanes with (phenylethynyl) lithium, and characterized by infrared (IR) spectra, nuclear magnetic resonance (NMR) and mass spectrometry (MS).
Three new 1, 3-bis (phenylethynyl) disilazanes were synthesized from the reaction of 1, 3-dichlorodisilazanes with (phenylethynyl) lithium, and characterized by infrared (IR) spectra, nuclear magnetic resonance (NMR) and mass spectrometry (MS).
2007, 18(11): 1353-1356
doi: 10.1016/j.cclet.2007.09.019
Abstract:
A solid-state mechanochemical processing, that is, pan-milling, was used to conduct the esterification of poly (vinyl alcohol) (PVA) with maleic anhydride (MA) through stress-induced reaction. FTIR spectrum study indicated the presence of ester linkages and olefinic double bonds in maleic anhydride cross-linked PVA. Thermal properties of the cross-linked product were characterized by DSC. The results showed its glass transition temperature was 20℃ higher than the original linear PVA and the thermal stability was also improved.
A solid-state mechanochemical processing, that is, pan-milling, was used to conduct the esterification of poly (vinyl alcohol) (PVA) with maleic anhydride (MA) through stress-induced reaction. FTIR spectrum study indicated the presence of ester linkages and olefinic double bonds in maleic anhydride cross-linked PVA. Thermal properties of the cross-linked product were characterized by DSC. The results showed its glass transition temperature was 20℃ higher than the original linear PVA and the thermal stability was also improved.
2007, 18(11): 1357-1360
doi: 10.1016/j.cclet.2007.09.030
Abstract:
A series of 2-aryl-1-arylmethyl-1H-1, 3-benzimidazoles was synthesized expeditiously in good yields from o-phenylenediamines and aldehydes in the presence of Fe (ClO4)3 without solvent at room temperature.
A series of 2-aryl-1-arylmethyl-1H-1, 3-benzimidazoles was synthesized expeditiously in good yields from o-phenylenediamines and aldehydes in the presence of Fe (ClO4)3 without solvent at room temperature.
2007, 18(11): 1361-1363
doi: 10.1016/j.cclet.2007.09.038
Abstract:
A new approach for asymmetric syntheses of (S) and (R)-3-n-butylphthalide (NBP) is presented. The diastereoselective addition of dibutylzinic to aromatic aldehyde 10 or 11 generated from isomannide-or isosorbide-derived chiral auxiliary afforded S-NBP or R-NBP in high optical yields.
A new approach for asymmetric syntheses of (S) and (R)-3-n-butylphthalide (NBP) is presented. The diastereoselective addition of dibutylzinic to aromatic aldehyde 10 or 11 generated from isomannide-or isosorbide-derived chiral auxiliary afforded S-NBP or R-NBP in high optical yields.
2007, 18(11): 1364-1366
doi: 10.1016/j.cclet.2007.09.017
Abstract:
A novel alkenoic acid ester, (E)-4-hydroxy-dodec-2-enedioic acid-12-O-methyl ester and a new benzophenone, ethyl (S)-3-[2-(3, 4-dihydroxybenzoyl)-4, 5-dihydroxyphenyl]-2-hydroxypropanoate, together with a known compound, (E)-4-hydroxy-dodec-2-enedioic acids were isolated from the roots of Ranunculus ternatus. Their structures were elucidated by spectroscopic methods.
A novel alkenoic acid ester, (E)-4-hydroxy-dodec-2-enedioic acid-12-O-methyl ester and a new benzophenone, ethyl (S)-3-[2-(3, 4-dihydroxybenzoyl)-4, 5-dihydroxyphenyl]-2-hydroxypropanoate, together with a known compound, (E)-4-hydroxy-dodec-2-enedioic acids were isolated from the roots of Ranunculus ternatus. Their structures were elucidated by spectroscopic methods.
2007, 18(11): 1367-1370
doi: 10.1016/j.cclet.2007.09.005
Abstract:
Two new flavone glycosides, isoetin-7-O-β-D-glucopyranosyl-2'-O-α-L-arabinopyranoside (1) and isoetin-7-O-β-D-glucopyranosyl-2'-O-α-D-glucopyranoside (2), a new lignan, mongolicumin A (3), and a new guaianolide, mongolicumin B (4) were isolated from the aerial part of Taraxacum mongolicum. Their structures were elucidated mainly by spectral analyses.
Two new flavone glycosides, isoetin-7-O-β-D-glucopyranosyl-2'-O-α-L-arabinopyranoside (1) and isoetin-7-O-β-D-glucopyranosyl-2'-O-α-D-glucopyranoside (2), a new lignan, mongolicumin A (3), and a new guaianolide, mongolicumin B (4) were isolated from the aerial part of Taraxacum mongolicum. Their structures were elucidated mainly by spectral analyses.
2007, 18(11): 1371-1373
doi: 10.1016/j.cclet.2007.09.024
Abstract:
We report a new optical behaviour of pure Co-Al-layered double hydroxide (LDH). It was found that the Co-Al-LDH sample could emit fluorescence without any fluorescent substances intercalated. Its excitation spectrum shows a maximum peak near the wavelength 370 nm, the maximum emission peak appears at 430 nm and the photoluminescence colour of the Co-Al-LDH sample is blue. This new optical property will be expected to extend the potential applications of LDHs in optical materials field.
We report a new optical behaviour of pure Co-Al-layered double hydroxide (LDH). It was found that the Co-Al-LDH sample could emit fluorescence without any fluorescent substances intercalated. Its excitation spectrum shows a maximum peak near the wavelength 370 nm, the maximum emission peak appears at 430 nm and the photoluminescence colour of the Co-Al-LDH sample is blue. This new optical property will be expected to extend the potential applications of LDHs in optical materials field.
2007, 18(11): 1374-1378
doi: 10.1016/j.cclet.2007.09.025
Abstract:
Nine pigment-protein complexes were separated and characterized from intact Chroomonas placoidea chloroplasts by IEF. The bands Ⅰ-Ⅵ with their isoelectric points (pI) values from 4 to 6 were phycocyanin components; bands Ⅷ and Ⅸ (pI=2.8-3.6) were chlorophyll-protein complexes. According to absorption and fluorescence spectra, band Ⅶ was designated as a novel phycocyanin-Chla/c2-protein complex (pI≈3.4-3.7). These results indicated that phycocyanin is structurally and functionally coupled with chlorophyll-protein complex in C. placoidea, and probably interacted with electrostatic force in combination.
Nine pigment-protein complexes were separated and characterized from intact Chroomonas placoidea chloroplasts by IEF. The bands Ⅰ-Ⅵ with their isoelectric points (pI) values from 4 to 6 were phycocyanin components; bands Ⅷ and Ⅸ (pI=2.8-3.6) were chlorophyll-protein complexes. According to absorption and fluorescence spectra, band Ⅶ was designated as a novel phycocyanin-Chla/c2-protein complex (pI≈3.4-3.7). These results indicated that phycocyanin is structurally and functionally coupled with chlorophyll-protein complex in C. placoidea, and probably interacted with electrostatic force in combination.
2007, 18(11): 1379-1382
doi: 10.1016/j.cclet.2007.09.034
Abstract:
A new alloaromadendrane-type sesquiterpene, (-)-alloaromadendrane-3β, 9β-diol (1), has been isolated from the aerial part of Caragana intermediia. The structure of (-)-alloaromadendrane-3β, 9β-diol (1) was established by spectroscopic methods, including X-ray analysis that provided its relative stereochemistry. Bioassay showed that (-)-alloaromadendrane-3β, 9β-diol (1) possesses anti-pyricularia oryzae P-2b activity with MIC value of 10 μg/mL.
A new alloaromadendrane-type sesquiterpene, (-)-alloaromadendrane-3β, 9β-diol (1), has been isolated from the aerial part of Caragana intermediia. The structure of (-)-alloaromadendrane-3β, 9β-diol (1) was established by spectroscopic methods, including X-ray analysis that provided its relative stereochemistry. Bioassay showed that (-)-alloaromadendrane-3β, 9β-diol (1) possesses anti-pyricularia oryzae P-2b activity with MIC value of 10 μg/mL.
2007, 18(11): 1383-1385
doi: 10.1016/j.cclet.2007.09.026
Abstract:
From the aerial part of Isodon serra, two new ent-6, 7-seco-kaurane-type diterpenoids, 15α, 20β-dihydroxy-6β-methoxy-6, 7-seco-6, 20-epoxy-1, 7-olide-ent-kaur-16-ene (1) and 6α, 15α-dihydroxy-20-aldehyde-6, 7-seco-6, 11α-epoxy-1, 7-olide-ent-kaur-16-ene (2) were isolated. Their structures were elucidated by spectroscopic means.
From the aerial part of Isodon serra, two new ent-6, 7-seco-kaurane-type diterpenoids, 15α, 20β-dihydroxy-6β-methoxy-6, 7-seco-6, 20-epoxy-1, 7-olide-ent-kaur-16-ene (1) and 6α, 15α-dihydroxy-20-aldehyde-6, 7-seco-6, 11α-epoxy-1, 7-olide-ent-kaur-16-ene (2) were isolated. Their structures were elucidated by spectroscopic means.
2007, 18(11): 1386-1388
doi: 10.1016/j.cclet.2007.09.028
Abstract:
A novel sesquiterpenoid, pterisemipol, was isolated from Pteris semipinnata L. Its skeleton, namely pterisane, was considered to be rearranged from protoilludane and its structure was elucidated on the basis of spectroscopic analysis.
A novel sesquiterpenoid, pterisemipol, was isolated from Pteris semipinnata L. Its skeleton, namely pterisane, was considered to be rearranged from protoilludane and its structure was elucidated on the basis of spectroscopic analysis.
2007, 18(11): 1389-1391
doi: 10.1016/j.cclet.2007.07.015
Abstract:
The prepartion crystal structure of complex Co (Hsae)2·2H2O (1, H2sae=N-salicylidene-2-iminoethanol) are reported X-ray analysis revealed that every six Co (Hsae)2 forms a cyclic chip and every 12 water forms a novel gear-like cluster. Acting as building blocks, the gear-like water cluster and complex chip are connected in A-B fashion and extend into one-dimensional supramolecular chain. Hydrogen bond is the primary bridging force in the formation of supramolecular framework.
The prepartion crystal structure of complex Co (Hsae)2·2H2O (1, H2sae=N-salicylidene-2-iminoethanol) are reported X-ray analysis revealed that every six Co (Hsae)2 forms a cyclic chip and every 12 water forms a novel gear-like cluster. Acting as building blocks, the gear-like water cluster and complex chip are connected in A-B fashion and extend into one-dimensional supramolecular chain. Hydrogen bond is the primary bridging force in the formation of supramolecular framework.
2007, 18(11): 1392-1394
doi: 10.1016/j.cclet.2007.09.016
Abstract:
A novel chiral stationary phase (CSP1) for ligand-exchange chromatography (CLEC) was prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol group on the surface of silica gel, and then introducing L-Pro as a chiral selector and hydrophobic octyl group to the silica gel surface simultaneously. The enantioseparations of 14 DL-amino acids on CSP1 were achieved with the enantioselectivity α ranging from 1.09 to 2.44 and the resolution Rs being between 0.8 and 6.3. The chromatographic performances of CSP1 with the bonded phase (CSP2) prepared using reference method were compared. The results showed that the column efficiency and resolution Rs of chiral stationary phase could be improved by using the above modifying method.
A novel chiral stationary phase (CSP1) for ligand-exchange chromatography (CLEC) was prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol group on the surface of silica gel, and then introducing L-Pro as a chiral selector and hydrophobic octyl group to the silica gel surface simultaneously. The enantioseparations of 14 DL-amino acids on CSP1 were achieved with the enantioselectivity α ranging from 1.09 to 2.44 and the resolution Rs being between 0.8 and 6.3. The chromatographic performances of CSP1 with the bonded phase (CSP2) prepared using reference method were compared. The results showed that the column efficiency and resolution Rs of chiral stationary phase could be improved by using the above modifying method.
2007, 18(11): 1395-1398
doi: 10.1016/j.cclet.2007.09.010
Abstract:
The colloidal crystal template or opal with a closed-packed face-centered cubic (fcc) lattice was prepared from monodisperse polystyrene (PS) spheres by vertical sedimentation. The template provided void space for infiltration of monomer precursor composed of acrylate acid, acrylamide and ammonium persulfate, as well as microgel from the subsequent copolymerization. The sample was immersed in dimethylbenzene for completely removing PS spheres to form PAM inverse opal hydrogels (IOHPAM) or PAM/PAA inverse opal hydrogels (IOHPAM/PAA) photonic crystals. The PS spheres were replaced by air spheres, which interconnected each other through the windows. The study of responses to pH show that there are two peaks for both IOHPAM and IOHPAM/PAA films, but the IOHPAM/PAA peaks shift to higher pH, and the peaks are independent with the AA content.
The colloidal crystal template or opal with a closed-packed face-centered cubic (fcc) lattice was prepared from monodisperse polystyrene (PS) spheres by vertical sedimentation. The template provided void space for infiltration of monomer precursor composed of acrylate acid, acrylamide and ammonium persulfate, as well as microgel from the subsequent copolymerization. The sample was immersed in dimethylbenzene for completely removing PS spheres to form PAM inverse opal hydrogels (IOHPAM) or PAM/PAA inverse opal hydrogels (IOHPAM/PAA) photonic crystals. The PS spheres were replaced by air spheres, which interconnected each other through the windows. The study of responses to pH show that there are two peaks for both IOHPAM and IOHPAM/PAA films, but the IOHPAM/PAA peaks shift to higher pH, and the peaks are independent with the AA content.
2007, 18(11): 1399-1402
doi: 10.1016/j.cclet.2007.09.027
Abstract:
Microwave irradiation was firstly attempted for the preparation of organic-based monoliths of poly (styrene-divinylbenzene-methacrylic acid), which single step in situ polymerization was carried out during 15 min. The column permeability, electrophoretic and chromatographic behaviors were comparatively evaluated using pressure-assisted CEC, CEC and low pressure-driven separation modes. The largest theoretical plates for the preparing column could be close to 18, 0000 plates/m for thiourea in the mode of p-CEC. It provided a viable alternative to traditional initiation means for the preparation of monolithic capillary columns.
Microwave irradiation was firstly attempted for the preparation of organic-based monoliths of poly (styrene-divinylbenzene-methacrylic acid), which single step in situ polymerization was carried out during 15 min. The column permeability, electrophoretic and chromatographic behaviors were comparatively evaluated using pressure-assisted CEC, CEC and low pressure-driven separation modes. The largest theoretical plates for the preparing column could be close to 18, 0000 plates/m for thiourea in the mode of p-CEC. It provided a viable alternative to traditional initiation means for the preparation of monolithic capillary columns.
2007, 18(11): 1403-1406
doi: 10.1016/j.cclet.2007.09.018
Abstract:
A novel fluorescence enhancement Cu2+chemosensor derived from coumarin was prepared. Emission study found that it exhibits evident Cu2+-amplified fluorescence prior to Co2+, Pb2+, Mg2+, Mn2+, Ni2+, Zn2+, Fe3+, Ag+ and Cd2+, and the largest emission enhancement factor is about 9 at a ratio of 2:1 (chemosensor 1/Cu2+)
A novel fluorescence enhancement Cu2+chemosensor derived from coumarin was prepared. Emission study found that it exhibits evident Cu2+-amplified fluorescence prior to Co2+, Pb2+, Mg2+, Mn2+, Ni2+, Zn2+, Fe3+, Ag+ and Cd2+, and the largest emission enhancement factor is about 9 at a ratio of 2:1 (chemosensor 1/Cu2+)
2007, 18(11): 1407-1410
doi: 10.1016/j.cclet.2007.09.006
Abstract:
N-Methylene phosphonic chitosan (NMPCS), an amphiphilic macromolecule with powerful chelating ability of Ca2+ ions, was synthesized and characterized. The physicochemical properties of NMPCS and the interactions between NMPCS and plasmid DNA were investigated by FTIR, 13C NMR, X-ray, agarose gel electrophoresis retardation assay, atomic force microscopy (AFM) and complexes with mean size of 80-210 nm were formed. Taking HeLa as host cell, luciferase expression mediated by NMPCS improved about 100 times compared to the expression mediated by chitosan.
N-Methylene phosphonic chitosan (NMPCS), an amphiphilic macromolecule with powerful chelating ability of Ca2+ ions, was synthesized and characterized. The physicochemical properties of NMPCS and the interactions between NMPCS and plasmid DNA were investigated by FTIR, 13C NMR, X-ray, agarose gel electrophoresis retardation assay, atomic force microscopy (AFM) and complexes with mean size of 80-210 nm were formed. Taking HeLa as host cell, luciferase expression mediated by NMPCS improved about 100 times compared to the expression mediated by chitosan.
2007, 18(11): 1411-1415
doi: 10.1016/j.cclet.2007.09.031
Abstract:
Ni-mSA-mCS bipolar membrane (BM) was prepared by sodium alginate (SA) and chitosan (CS), which were modified by Ca2+ and glutaraldehyde as linking reagents, respectively. mSA-mCS membrane was characterized by FTIR, SEM, TG and used as a separator in the electrolysis cell to produce thioglycolic acid (TGA). The experiment results show that TGA was prepared effectively by electro-reduction of dithiodiglycolic acid (DTDGA) with the mixture of TGA and DTDGA in the cathodic chamber. The current efficiency was up to 66.7% at the room temperature (25℃) during the current density of 10 mA/cm2. Compared with the traditional metal reduction method, the electro-reduction technology saves the zinc powder and eliminates the pollution to environment.
Ni-mSA-mCS bipolar membrane (BM) was prepared by sodium alginate (SA) and chitosan (CS), which were modified by Ca2+ and glutaraldehyde as linking reagents, respectively. mSA-mCS membrane was characterized by FTIR, SEM, TG and used as a separator in the electrolysis cell to produce thioglycolic acid (TGA). The experiment results show that TGA was prepared effectively by electro-reduction of dithiodiglycolic acid (DTDGA) with the mixture of TGA and DTDGA in the cathodic chamber. The current efficiency was up to 66.7% at the room temperature (25℃) during the current density of 10 mA/cm2. Compared with the traditional metal reduction method, the electro-reduction technology saves the zinc powder and eliminates the pollution to environment.
2007, 18(11): 1416-1418
doi: 10.1016/j.cclet.2007.09.015
Abstract:
Glutamic acid-salicylaldehyde Schiff-base metal complexes are bound into bovine serum albumin (BSA), which afforded BSA binding Schiff-base metal complexes (BSA-SalGluM, M=Cu, Co, Ni, Zn). The BSA binding metal complexes were characterized by UV-vis spectra and Native PAGE. It showed that the protein structures of BSA kept after coordinating amino acid Schiff-bases metal complexes. The effect of the antioxidant activity was investigated. The results indicate that the antioxidant capacity of BSA increased more than 10 times after binding Schiff-base metal complexes.
Glutamic acid-salicylaldehyde Schiff-base metal complexes are bound into bovine serum albumin (BSA), which afforded BSA binding Schiff-base metal complexes (BSA-SalGluM, M=Cu, Co, Ni, Zn). The BSA binding metal complexes were characterized by UV-vis spectra and Native PAGE. It showed that the protein structures of BSA kept after coordinating amino acid Schiff-bases metal complexes. The effect of the antioxidant activity was investigated. The results indicate that the antioxidant capacity of BSA increased more than 10 times after binding Schiff-base metal complexes.
2007, 18(11): 1419-1422
doi: 10.1016/j.cclet.2007.09.001
Abstract:
This paper investigated average cluster sizes (ACS) and cluster size distributions (CSD) at different shear rates by Brownian dynamics in non-, bi-, and uni-polar systems with partly charged superfine particles. The investigation indicates that clusters in nonpolar systems are the weakest and easiest to be damaged by increasing shear stresses; charged particles play important and different roles:in bi-polar system, it intends to strengthen clusters to some extent provided that the sign-like ions homogeneously arranged; in uni-polar system charged particles cracked the clusters into smaller ones, but the small clusters are strong to stand with larger shear stress. The relationship between ACS and shear rates follows power law with exponents in a range 0.18-0.28, these values are in a good agreement with experiment range but at the lower limit compared with other systems of non-metallic cluster particles.
This paper investigated average cluster sizes (ACS) and cluster size distributions (CSD) at different shear rates by Brownian dynamics in non-, bi-, and uni-polar systems with partly charged superfine particles. The investigation indicates that clusters in nonpolar systems are the weakest and easiest to be damaged by increasing shear stresses; charged particles play important and different roles:in bi-polar system, it intends to strengthen clusters to some extent provided that the sign-like ions homogeneously arranged; in uni-polar system charged particles cracked the clusters into smaller ones, but the small clusters are strong to stand with larger shear stress. The relationship between ACS and shear rates follows power law with exponents in a range 0.18-0.28, these values are in a good agreement with experiment range but at the lower limit compared with other systems of non-metallic cluster particles.
2007, 18(11): 1423-1426
doi: 10.1016/j.cclet.2007.09.007
Abstract:
Based on the expression of the index of coil interpenetration (i. e., the degree of coil overlap, ξb) of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb=ρb[η]θ/1.66 via Flory's intrinsic viscosity equation at theta conditions. The ξb of poly (vinyl chloride) (PVC) dense membranes with different molecular weights and cellulose diacetate (CA) dense membranes prepared using different solvents were determined. The permeability, permeation coefficient (P) of nitrogen and permeation flux (J) of liquid through both membranes, respectively, was measured. P and J decreased exponentially with increasing ξb for PVC and CA membranes were revealed.
Based on the expression of the index of coil interpenetration (i. e., the degree of coil overlap, ξb) of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb=ρb[η]θ/1.66 via Flory's intrinsic viscosity equation at theta conditions. The ξb of poly (vinyl chloride) (PVC) dense membranes with different molecular weights and cellulose diacetate (CA) dense membranes prepared using different solvents were determined. The permeability, permeation coefficient (P) of nitrogen and permeation flux (J) of liquid through both membranes, respectively, was measured. P and J decreased exponentially with increasing ξb for PVC and CA membranes were revealed.
2007, 18(11): 1427-1430
doi: 10.1016/j.cclet.2007.09.021
Abstract:
Taking the Lindemann model as a sample system in which there exist chemical reactions, diffusion and heat conduction, we found the theoretical framework of linear stability analysis for a unidimensional nonhomogeneous two-variable system with one end subject to Dirichlet conditions, while the other end no-flux conditions. Furthermore, the conditions for the emergence of temperature waves are found out by the linear stabiliy analysis and verified by a diagram for successive steps of evolution of spatial profile of temperature during a period that is plotted by numerical simulations on a computer. Without doubt, these results are in favor of the heat balance in chemical reactor designs.
Taking the Lindemann model as a sample system in which there exist chemical reactions, diffusion and heat conduction, we found the theoretical framework of linear stability analysis for a unidimensional nonhomogeneous two-variable system with one end subject to Dirichlet conditions, while the other end no-flux conditions. Furthermore, the conditions for the emergence of temperature waves are found out by the linear stabiliy analysis and verified by a diagram for successive steps of evolution of spatial profile of temperature during a period that is plotted by numerical simulations on a computer. Without doubt, these results are in favor of the heat balance in chemical reactor designs.
