Login In
2007 Volume 18 Issue 9
2007, 18(9): 1021-1024
doi: 10.1016/j.cclet.2007.07.021
Abstract:
A novel series of unsymmetrical porphyrins with aldehyde group at the terminal of the linkage which connected to meso-phenyl through acylamide bond have been synthesized and structurally characterized by IR, 1H NMR, MS, UV-vis, fluorescence.
A novel series of unsymmetrical porphyrins with aldehyde group at the terminal of the linkage which connected to meso-phenyl through acylamide bond have been synthesized and structurally characterized by IR, 1H NMR, MS, UV-vis, fluorescence.
2007, 18(9): 1025-1028
doi: 10.1016/j.cclet.2007.06.025
Abstract:
Cu-catalyzed oxidation of 5-hexyl-1, 3-dihydroimidazo-2-one (1) in the presence of propylamine, as surrogates for the oxidized His side chain and Lys side chain, was investigated. 5-Hexylidene-4-propylamino-1, 5-dihydroimidazol-2-one (2), a model His-Lys cross-link product, was isolated and structurally characterized by NMR and mass spectrometry.
Cu-catalyzed oxidation of 5-hexyl-1, 3-dihydroimidazo-2-one (1) in the presence of propylamine, as surrogates for the oxidized His side chain and Lys side chain, was investigated. 5-Hexylidene-4-propylamino-1, 5-dihydroimidazol-2-one (2), a model His-Lys cross-link product, was isolated and structurally characterized by NMR and mass spectrometry.
2007, 18(9): 1029-1032
doi: 10.1016/j.cclet.2007.06.024
Abstract:
An efficient isomerization of alkynyl ketones to (E, E)-diene ketones was developed. The reaction catalyzed by 20 mol%triphenylphosphine in aqueous media gave the desired products in good yields.
An efficient isomerization of alkynyl ketones to (E, E)-diene ketones was developed. The reaction catalyzed by 20 mol%triphenylphosphine in aqueous media gave the desired products in good yields.
2007, 18(9): 1033-1036
doi: 10.1016/j.cclet.2007.07.028
Abstract:
Cu-catalyzed cross coupling between phosphinic amides and aryl halides was accomplished for the first time by using (±)-trans-cyclohexane-1, 2-diamine as the ligand. This reaction provided a novel approach for synthesizing arylated phosphinic amides. Both kinetic measurement and theoretical calculation indicated that phosphinic amides were much less reactive than amides by about 10times in Cu-catalyzed cross coupling.
Cu-catalyzed cross coupling between phosphinic amides and aryl halides was accomplished for the first time by using (±)-trans-cyclohexane-1, 2-diamine as the ligand. This reaction provided a novel approach for synthesizing arylated phosphinic amides. Both kinetic measurement and theoretical calculation indicated that phosphinic amides were much less reactive than amides by about 10times in Cu-catalyzed cross coupling.
2007, 18(9): 1037-1039
doi: 10.1016/j.cclet.2007.06.028
Abstract:
A new method for the synthesis of 4, 4', 6, 6'-tetra (azido) azo-1, 3, 5-triazine (TAAT) is described. The key intermediate 4, 4', 6, 6'-tetra (azido) hydrazo-1, 3, 5-triazine (THAT) was synthesized by nucleophilic substitution in the case of sodium azide as nucleophile. N-Bromosuccinide (NBS) was used as oxidant to oxidize THAT by a tractable operation under mild reaction condition. The target compound TAAT was obtained with a facile process and high overall yield of 81%. The structures of TAAT and its intermediates were identified by spectroscopic methods.
A new method for the synthesis of 4, 4', 6, 6'-tetra (azido) azo-1, 3, 5-triazine (TAAT) is described. The key intermediate 4, 4', 6, 6'-tetra (azido) hydrazo-1, 3, 5-triazine (THAT) was synthesized by nucleophilic substitution in the case of sodium azide as nucleophile. N-Bromosuccinide (NBS) was used as oxidant to oxidize THAT by a tractable operation under mild reaction condition. The target compound TAAT was obtained with a facile process and high overall yield of 81%. The structures of TAAT and its intermediates were identified by spectroscopic methods.
2007, 18(9): 1040-1042
doi: 10.1016/j.cclet.2007.06.017
Abstract:
Functionalized alkylzinc iodides will undergo 1, 4-conjugation reaction with derivatives of β-nitrostyrene in the presence of Cu (Oac) 2/LiCl to afford a polyfunctional nitro-compound in high yield.
Functionalized alkylzinc iodides will undergo 1, 4-conjugation reaction with derivatives of β-nitrostyrene in the presence of Cu (Oac) 2/LiCl to afford a polyfunctional nitro-compound in high yield.
2007, 18(9): 1043-1046
doi: 10.1016/j.cclet.2007.06.023
Abstract:
Palladium-catalyzed homo-coupling of arylboronic acids could proceed smoothly with a commercially available resin functionlised by phosphino or amino group as the ligand in supercritical carbon dioxide thereby offering a simple and efficient protocol for the synthesis of symmetrical bi-aryl molecules and their higher homologues.
Palladium-catalyzed homo-coupling of arylboronic acids could proceed smoothly with a commercially available resin functionlised by phosphino or amino group as the ligand in supercritical carbon dioxide thereby offering a simple and efficient protocol for the synthesis of symmetrical bi-aryl molecules and their higher homologues.
2007, 18(9): 1047-1048
doi: 10.1016/j.cclet.2007.05.049
Abstract:
A facile one-pot synthesis of 2, 5-disubstituted-1, 3, 4-thiadiazoles was achieved by ultrasonic irradiation of a mixture of lnaphthylacetyl chloride, NH4CNS, CH2Cl2 and PEG-400 for 1.5 h at 10-20℃ and subsequent irradiation for 1.5 h in the presence of N-arylglycine hydrazides. This method requires short time and gives thiadiazoles in high yields.
A facile one-pot synthesis of 2, 5-disubstituted-1, 3, 4-thiadiazoles was achieved by ultrasonic irradiation of a mixture of lnaphthylacetyl chloride, NH4CNS, CH2Cl2 and PEG-400 for 1.5 h at 10-20℃ and subsequent irradiation for 1.5 h in the presence of N-arylglycine hydrazides. This method requires short time and gives thiadiazoles in high yields.
2007, 18(9): 1049-1052
doi: 10.1016/j.cclet.2007.07.009
Abstract:
Isovaleraldehyde possesses malty, fruity, cocoa-like odor and is widely used in fruit, chocolate, coffee flavors. The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper. The effects of the ratio of D-glucose/L-leucine, reaction temperature and pH value on the yield of isovaleraldehyde were explored. The optimum conditions were as follows:n (D-glucose):n (L-leucine)=4, temperature 150℃, reaction time 3 h, pH 5. The highest yield of isovaleraldehyde obtained was about 32%.
Isovaleraldehyde possesses malty, fruity, cocoa-like odor and is widely used in fruit, chocolate, coffee flavors. The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper. The effects of the ratio of D-glucose/L-leucine, reaction temperature and pH value on the yield of isovaleraldehyde were explored. The optimum conditions were as follows:n (D-glucose):n (L-leucine)=4, temperature 150℃, reaction time 3 h, pH 5. The highest yield of isovaleraldehyde obtained was about 32%.
Selective oxidation of ethylbenzene catalyzed by fluorinated metalloporphyrins with molecular oxygen
2007, 18(9): 1053-1056
doi: 10.1016/j.cclet.2007.06.019
Abstract:
This paper reported the oxidation of ethylbenzene catalyzed by fluorinated metalloporphyrins under mild conditions without any additives. The results showed that the cobalt (Ⅱ) (5, 10, 15, 20-tetrakis (pentafluorophenyl)) porphyrin was the best catalyst among the fluorinated metalloporphyrins. The conversion of ethylbenzene reached 38.6%, the selectivity to acetophenone reached 94.0%, and the turnover number is 2719 under the optimal conditions.
This paper reported the oxidation of ethylbenzene catalyzed by fluorinated metalloporphyrins under mild conditions without any additives. The results showed that the cobalt (Ⅱ) (5, 10, 15, 20-tetrakis (pentafluorophenyl)) porphyrin was the best catalyst among the fluorinated metalloporphyrins. The conversion of ethylbenzene reached 38.6%, the selectivity to acetophenone reached 94.0%, and the turnover number is 2719 under the optimal conditions.
2007, 18(9): 1057-1060
doi: 10.1016/j.cclet.2007.07.004
Abstract:
Various biologically important perimidine derivatives have been synthesized efficiently from various ketones and naphthalene-1, 8-diamine by using a catalytic amount of RuCl3 (1 mol%). This method is a very simple and high yielding reaction for the synthesis of perimidine derivatives.
Various biologically important perimidine derivatives have been synthesized efficiently from various ketones and naphthalene-1, 8-diamine by using a catalytic amount of RuCl3 (1 mol%). This method is a very simple and high yielding reaction for the synthesis of perimidine derivatives.
2007, 18(9): 1061-1063
doi: 10.1016/j.cclet.2007.07.035
Abstract:
It is described that indium-mediated allylation of trichloromethyl ketones could afford the corresponding homoallylic alcohols smoothly in aqueous media.
It is described that indium-mediated allylation of trichloromethyl ketones could afford the corresponding homoallylic alcohols smoothly in aqueous media.
2007, 18(9): 1064-1066
doi: 10.1016/j.cclet.2007.06.031
Abstract:
Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO3 under solvent free oxidation at room temperature.
Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO3 under solvent free oxidation at room temperature.
2007, 18(9): 1067-1070
doi: 10.1016/j.cclet.2007.06.030
Abstract:
A facile, rapid and efficient method for the synthesis of molecular tweezers containing chiral unsymmetrical urea unit in solventfree conditions using microwave was reported.
A facile, rapid and efficient method for the synthesis of molecular tweezers containing chiral unsymmetrical urea unit in solventfree conditions using microwave was reported.
2007, 18(9): 1071-1074
doi: 10.1016/j.cclet.2007.07.005
Abstract:
A novel double chained amphiphile, N-(α-4-hexylphenoxy)-lauroyltaurate (abbreviated as 10+6B-T), has been synthesized. The structures of main intermediate products and the title product were characterized by 1H NMR. The new amphiphile shows high surface activity. The critical micelle concentration (cmc), which is 1.1×10-5 mol/L, is much lower than that of conventional double chained surfactants, such as sodium bis (2-ethylhexyl) sulfosuccinate (AOT).
A novel double chained amphiphile, N-(α-4-hexylphenoxy)-lauroyltaurate (abbreviated as 10+6B-T), has been synthesized. The structures of main intermediate products and the title product were characterized by 1H NMR. The new amphiphile shows high surface activity. The critical micelle concentration (cmc), which is 1.1×10-5 mol/L, is much lower than that of conventional double chained surfactants, such as sodium bis (2-ethylhexyl) sulfosuccinate (AOT).
2007, 18(9): 1075-1077
doi: 10.1016/j.cclet.2007.06.022
Abstract:
Two new α, β-unsaturated butyrolactone derivatives, 4-(4"-hydroxybenzyl)-3-(3'-hydroxy-phenethyl) furan-2 (5H)-one (1) and 3-(3'-hydroxyphenethyl) furan-2 (5H)-one (2), together with one known phenolic compound (3), were isolated from the tubers of Pleione bulbocodioides (Franch.) Rolfe. Their structures were elucidated by analysis of spectroscopic data.
Two new α, β-unsaturated butyrolactone derivatives, 4-(4"-hydroxybenzyl)-3-(3'-hydroxy-phenethyl) furan-2 (5H)-one (1) and 3-(3'-hydroxyphenethyl) furan-2 (5H)-one (2), together with one known phenolic compound (3), were isolated from the tubers of Pleione bulbocodioides (Franch.) Rolfe. Their structures were elucidated by analysis of spectroscopic data.
2007, 18(9): 1078-1080
doi: 10.1016/j.cclet.2007.06.026
Abstract:
A new triterpenoid saponin, named clematiganoside A (1), was isolated from the whole plant of Clematis ganpiniana. Its structure was elucidated on the basis of 1D, 2D NMR, TOF-MS and ESI-MS techniques, and physicochemical properties.
A new triterpenoid saponin, named clematiganoside A (1), was isolated from the whole plant of Clematis ganpiniana. Its structure was elucidated on the basis of 1D, 2D NMR, TOF-MS and ESI-MS techniques, and physicochemical properties.
2007, 18(9): 1081-1083
doi: 10.1016/j.cclet.2007.07.003
Abstract:
A new cyclodipeptide, cyclo (phenylalanyl-N-methyltyrosyl) 1, was isolated from the mycelial solid cultures of Geotrichum candidum. Its structure was elucidated by spectroscopic methods. The antifungal activity of the new compound against Peronophythora litchii was assessed by microplate Alamar blue assay (MABA).
A new cyclodipeptide, cyclo (phenylalanyl-N-methyltyrosyl) 1, was isolated from the mycelial solid cultures of Geotrichum candidum. Its structure was elucidated by spectroscopic methods. The antifungal activity of the new compound against Peronophythora litchii was assessed by microplate Alamar blue assay (MABA).
2007, 18(9): 1084-1086
doi: 10.1016/j.cclet.2007.07.006
Abstract:
Two new indole alkaloids, 4-oxo-4, 12-dihydroindolo[2, 3-a]quinolizine-3-carbaldehyde (1) and 1, 6, 7-trihydro-indolo-[2, 3-a]furan[3, 4-g]quinolizine-3, 4 (13H)-dione (2), were isolated from Nauclea officinalis. Their structures were determined on the basis of 1D and 2D NMR spectral data.
Two new indole alkaloids, 4-oxo-4, 12-dihydroindolo[2, 3-a]quinolizine-3-carbaldehyde (1) and 1, 6, 7-trihydro-indolo-[2, 3-a]furan[3, 4-g]quinolizine-3, 4 (13H)-dione (2), were isolated from Nauclea officinalis. Their structures were determined on the basis of 1D and 2D NMR spectral data.
2007, 18(9): 1087-1088
doi: 10.1016/j.cclet.2007.07.033
Abstract:
A new phenolic constituent along with five known compounds were isolated from Fagopyrum dibotrys (D. Don) Hara. The new compound was characterized as 1, 3-dimethoxy-2-O-β-xylo-pyranosyl-5-O-β-glucopyranosyl-benzene, by spectroscopic analysis and enzymatic hydrolysis.
A new phenolic constituent along with five known compounds were isolated from Fagopyrum dibotrys (D. Don) Hara. The new compound was characterized as 1, 3-dimethoxy-2-O-β-xylo-pyranosyl-5-O-β-glucopyranosyl-benzene, by spectroscopic analysis and enzymatic hydrolysis.
2007, 18(9): 1089-1091
doi: 10.1016/j.cclet.2007.07.011
Abstract:
A novel phenanthro[2, 3-b] furan 1, named (3-hydroxy-9-(4'-hydroxy-3'-methoxyphenyl)-11-methoxy-5, 6, 9, 10-tetrahydrophenanthro[2, 3-b] furan-10-yl) methyl acetate, and two known phenolic compounds were isolated from the tubers of Pleione bulbocodioides (Franch.) Rolfe. Their structures were elucidated by spectroscopic methods.
A novel phenanthro[2, 3-b] furan 1, named (3-hydroxy-9-(4'-hydroxy-3'-methoxyphenyl)-11-methoxy-5, 6, 9, 10-tetrahydrophenanthro[2, 3-b] furan-10-yl) methyl acetate, and two known phenolic compounds were isolated from the tubers of Pleione bulbocodioides (Franch.) Rolfe. Their structures were elucidated by spectroscopic methods.
2007, 18(9): 1092-1094
doi: 10.1016/j.cclet.2007.07.036
Abstract:
A new isoflavane named astraganoside, together with five known compounds had been isolated from the processed Astragralus membranaceus. The structure of the novel compound was elucidated as (3R, 4R)-3-(2-hydroxy-3, 4-dimethoxyphenyl) chroman-4, 7-diol-7-O-β-D-glucopyranoside (1) based on spectroscopic methods including UV, IR, ESI-MS, 1D NMR and 2D NMR techniques.
A new isoflavane named astraganoside, together with five known compounds had been isolated from the processed Astragralus membranaceus. The structure of the novel compound was elucidated as (3R, 4R)-3-(2-hydroxy-3, 4-dimethoxyphenyl) chroman-4, 7-diol-7-O-β-D-glucopyranoside (1) based on spectroscopic methods including UV, IR, ESI-MS, 1D NMR and 2D NMR techniques.
2007, 18(9): 1095-1098
doi: 10.1016/j.cclet.2007.06.015
Abstract:
Based on the fact that some metal ions can catalyze the chemiluminescence (CL) reaction of luminol with K3Fe (CN) 6, a novel capillary electrophoresis CL method was developed for the determination of Co (Ⅱ) and Cu (Ⅱ). The separation was carried out with a 10 mmol/L sodium acetate solution containing 0.8 mmol/L luminol and 2.0 mmol/L α-HIBA (adjusted to pH 4.8 by Hac solution). The post-capillary reagent was 2.0 mmol/L K3Fe (CN) 6which was adjusted to pH 13.0 by NaOH solution. Under the optimum conditions, the detection limits (S/N=3) for Co (Ⅱ) and Cu (Ⅱ) were 7.5×10-11 mol/L and 7.5×10-9 mol/L, with the linear range of 7.5×10-9 mol/L to 1.0×10-6 mol/L and 7.5×10-8 mol/L to 5.0×10-5 mol/L, respectively.
Based on the fact that some metal ions can catalyze the chemiluminescence (CL) reaction of luminol with K3Fe (CN) 6, a novel capillary electrophoresis CL method was developed for the determination of Co (Ⅱ) and Cu (Ⅱ). The separation was carried out with a 10 mmol/L sodium acetate solution containing 0.8 mmol/L luminol and 2.0 mmol/L α-HIBA (adjusted to pH 4.8 by Hac solution). The post-capillary reagent was 2.0 mmol/L K3Fe (CN) 6which was adjusted to pH 13.0 by NaOH solution. Under the optimum conditions, the detection limits (S/N=3) for Co (Ⅱ) and Cu (Ⅱ) were 7.5×10-11 mol/L and 7.5×10-9 mol/L, with the linear range of 7.5×10-9 mol/L to 1.0×10-6 mol/L and 7.5×10-8 mol/L to 5.0×10-5 mol/L, respectively.
2007, 18(9): 1099-1102
doi: 10.1016/j.cclet.2007.06.020
Abstract:
In an acetic acid-sodium acetate buffer solution of pH 3.6-6.8, a compound complex was formed between sodium hyaluronate (abbreviated as SH) and some basic bisphenylnaphthylmethane dyes, leading to a great enhancement of the intensity of resonance Rayleigh scattering (RRS) and giving a new RRS spectrum, with its maximum scattering peak near 280 nm. It was also found that the intensity of RRS was directly proportional to the concentration of SH near the range between 0 and 3.0 mg/L. Based on these facts, a sensitive method for the determination of SH has been established. The method had good selectivity, and has been used for the determination of total amounts of SH in samples with satisfactory results. For the NB-SH system, the detection limit of SH was down to 13.7 ng/mL.
In an acetic acid-sodium acetate buffer solution of pH 3.6-6.8, a compound complex was formed between sodium hyaluronate (abbreviated as SH) and some basic bisphenylnaphthylmethane dyes, leading to a great enhancement of the intensity of resonance Rayleigh scattering (RRS) and giving a new RRS spectrum, with its maximum scattering peak near 280 nm. It was also found that the intensity of RRS was directly proportional to the concentration of SH near the range between 0 and 3.0 mg/L. Based on these facts, a sensitive method for the determination of SH has been established. The method had good selectivity, and has been used for the determination of total amounts of SH in samples with satisfactory results. For the NB-SH system, the detection limit of SH was down to 13.7 ng/mL.
2007, 18(9): 1103-1106
doi: 10.1016/j.cclet.2007.07.007
Abstract:
The characteristics, performance and application of membrane electrode based on ion associate of diclofenac with base dye Safranine T are described. The electrode response to diclofenac has the sensitivity of 47±1.0 mV decade-1 over the range of 5×10-5 to 5×10-2 mol/L at pH 6-12, and the detection limit of 3.2×10-5 mol/L. The electrode is easy assembled at a relatively low cost has fast response time (2-4 s) and can be used for a period up to 3.5 months without any considerable divergence in potential. The proposed sensor displayed good selectivity for diclofenac in the presence of different substances. It was used to determine diclofenac in pharmaceuticals by means of the standard addition method.
The characteristics, performance and application of membrane electrode based on ion associate of diclofenac with base dye Safranine T are described. The electrode response to diclofenac has the sensitivity of 47±1.0 mV decade-1 over the range of 5×10-5 to 5×10-2 mol/L at pH 6-12, and the detection limit of 3.2×10-5 mol/L. The electrode is easy assembled at a relatively low cost has fast response time (2-4 s) and can be used for a period up to 3.5 months without any considerable divergence in potential. The proposed sensor displayed good selectivity for diclofenac in the presence of different substances. It was used to determine diclofenac in pharmaceuticals by means of the standard addition method.
2007, 18(9): 1107-1110
doi: 10.1016/j.cclet.2007.07.008
Abstract:
Two rapid, sensitive and reliable immunoassay methods, namely competitive indirect enzyme-linked immunosorbent assay (CIELISA) and colloidal gold-based immunochromatographic assay (CGIA), were developed to detect ofloxacin (OFL). The linear range of the CI-ELISA was from 0.5 to 128 ng/mL with a limit of detection (LOD) of 0.35 ng/mL. Good recoveries were obtained in analyzing simulated swine urine samples. The CGIA could accurately estimate OFL at concentrations as low as 10 ng/mL in less than 10 min, and test results were read visually without any instrument.
Two rapid, sensitive and reliable immunoassay methods, namely competitive indirect enzyme-linked immunosorbent assay (CIELISA) and colloidal gold-based immunochromatographic assay (CGIA), were developed to detect ofloxacin (OFL). The linear range of the CI-ELISA was from 0.5 to 128 ng/mL with a limit of detection (LOD) of 0.35 ng/mL. Good recoveries were obtained in analyzing simulated swine urine samples. The CGIA could accurately estimate OFL at concentrations as low as 10 ng/mL in less than 10 min, and test results were read visually without any instrument.
2007, 18(9): 1111-1114
doi: 10.1016/j.cclet.2007.07.034
Abstract:
Gold nanotubule membranes were prepared by using electroless deposition of gold within the pores and surfaces of polycarbonate track-etched membranes. And the gold nanotubule membrane was used as an electrode for determination of uric acid in urine samples for the first time. In Britton-Robinson buffer of pH 4.56, uric acid exhibited well-defined differential pulse voltammograms. And the interference between coexistent ascorbic acid and uric acid was overcome owing to the attractive ability of the gold nanotubule electrode to yield a large anodic peak difference ca. 0.404 V (vs. SCE). The proposed method was then applied to the determination of uric acid in urine without any pretreatment.
Gold nanotubule membranes were prepared by using electroless deposition of gold within the pores and surfaces of polycarbonate track-etched membranes. And the gold nanotubule membrane was used as an electrode for determination of uric acid in urine samples for the first time. In Britton-Robinson buffer of pH 4.56, uric acid exhibited well-defined differential pulse voltammograms. And the interference between coexistent ascorbic acid and uric acid was overcome owing to the attractive ability of the gold nanotubule electrode to yield a large anodic peak difference ca. 0.404 V (vs. SCE). The proposed method was then applied to the determination of uric acid in urine without any pretreatment.
2007, 18(9): 1115-1118
doi: 10.1016/j.cclet.2007.07.032
Abstract:
This present study investigated the ability of various soy protein hydrolysates (SPHs) in binding calcium. It was demonstrated that the amount of Ca-bound depended greatly on the SPHs obtained using different proteases, which included:neutrase, flavourzyme, protease M and pepsin. The maximum level of Ca-bound (66.9 mg/g) occurred when protease M was used to hydrolyze soy protein. Peptide fragments exhibiting high Ca-binding capacity had molecular weights of either 14.4 or 8-9 kDa. The level of Ca-bound increased linearly with the increment of carboxyl content in SPHs, and further deamidation on SPHs from protease M improved Ca-binding of the hydrolysate.
This present study investigated the ability of various soy protein hydrolysates (SPHs) in binding calcium. It was demonstrated that the amount of Ca-bound depended greatly on the SPHs obtained using different proteases, which included:neutrase, flavourzyme, protease M and pepsin. The maximum level of Ca-bound (66.9 mg/g) occurred when protease M was used to hydrolyze soy protein. Peptide fragments exhibiting high Ca-binding capacity had molecular weights of either 14.4 or 8-9 kDa. The level of Ca-bound increased linearly with the increment of carboxyl content in SPHs, and further deamidation on SPHs from protease M improved Ca-binding of the hydrolysate.
2007, 18(9): 1119-1123
doi: 10.1016/j.cclet.2007.06.008
Abstract:
The synthesis and phosphorescence properties of two novel Ir (Ⅲ) complexes bearing tert-butyl substituents, bis (4-tert-butyl-2-phenylbenzothiozolato-N, C2') iridium (Ⅲ) (acetylacetonate)[(tbt) 2Ir (acac)] and bis (4-tert-butyl-1-phenyl-1H-benzimidazolatoN, C2') iridium (Ⅲ) (acetylacetonate)[(tpbi) 2Ir (acac)], are reported, their molecular structures are confirmed by 1H NMR, ESI-MS and elementary analysis. Photoluminescence (PL) studies revealed that they can emit strong green and orange phosphorescence in high quantum yields. Compared to their prototypes lacking of tert-butyl substituents, the two novel iridium (Ⅲ) complexes both have shorter lifetimes and improved or nearly similar PL quantum efficiencies, implying that the exciton quenching is inhibited effectively when molecular steric hindrance increases. The two chelates have great potential to be used as electrophosphorescent materials.
The synthesis and phosphorescence properties of two novel Ir (Ⅲ) complexes bearing tert-butyl substituents, bis (4-tert-butyl-2-phenylbenzothiozolato-N, C2') iridium (Ⅲ) (acetylacetonate)[(tbt) 2Ir (acac)] and bis (4-tert-butyl-1-phenyl-1H-benzimidazolatoN, C2') iridium (Ⅲ) (acetylacetonate)[(tpbi) 2Ir (acac)], are reported, their molecular structures are confirmed by 1H NMR, ESI-MS and elementary analysis. Photoluminescence (PL) studies revealed that they can emit strong green and orange phosphorescence in high quantum yields. Compared to their prototypes lacking of tert-butyl substituents, the two novel iridium (Ⅲ) complexes both have shorter lifetimes and improved or nearly similar PL quantum efficiencies, implying that the exciton quenching is inhibited effectively when molecular steric hindrance increases. The two chelates have great potential to be used as electrophosphorescent materials.
2007, 18(9): 1124-1128
doi: 10.1016/j.cclet.2007.07.014
Abstract:
The electrochemical formation of Mg-Li alloys was investigated in a molten LiCl-KCl (58-42 mol%) eutectic melt at 723 K. The cyclic voltammogram for a Mo electrode showed that the electroreduction of Li+ proceeds in a single step and the deposition potential of Li metal was -2.40 V (vs. Ag/AgCl). For Mg electrode, the electroreduction of Li+ takes place at less cathodic potential than that at the Mo electrode which was caused by the formation of Mg-Li alloys. Phase of the deposited Mg-Li alloys could be controlled by the electrolysis potential, and the samples were characterized by X-ray diffraction and scanning electron microscopy. The results showed that α-Mg and β-Li phases were obtained at -2.35 and -2.55 V, respectively.
The electrochemical formation of Mg-Li alloys was investigated in a molten LiCl-KCl (58-42 mol%) eutectic melt at 723 K. The cyclic voltammogram for a Mo electrode showed that the electroreduction of Li+ proceeds in a single step and the deposition potential of Li metal was -2.40 V (vs. Ag/AgCl). For Mg electrode, the electroreduction of Li+ takes place at less cathodic potential than that at the Mo electrode which was caused by the formation of Mg-Li alloys. Phase of the deposited Mg-Li alloys could be controlled by the electrolysis potential, and the samples were characterized by X-ray diffraction and scanning electron microscopy. The results showed that α-Mg and β-Li phases were obtained at -2.35 and -2.55 V, respectively.
2007, 18(9): 1129-1132
doi: 10.1016/j.cclet.2007.06.016
Abstract:
The effect of flexible spacer length on the liquid crystalline property of ABA-type triblock copolymers containing azobenzene groups was investigated. For the study, the monomers, n-[4-(4-ethoxyphenylazo) phenoxy]alkyl methacrylates with varying methylene groups (n=0, 2, 6) were used to synthesize a series of azobenzene-containing amphiphilic triblock copolymers PAnC-PEG-PAnC by atom transfer radical polymerization (ATRP). Differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and one-dimensional X-ray diffraction (1D WAXD) have shown that the glass transition temperatures of these copolymers decreased with increasing n, PA0C-PEG-PA0C has no mesophase, while both PA2C-PEG-PA2C and PA6C-PEGPA6C have a nematic mesophase. These differences derive from the length of spacer groups between the polymer backbone and side-chain LC monomers.
The effect of flexible spacer length on the liquid crystalline property of ABA-type triblock copolymers containing azobenzene groups was investigated. For the study, the monomers, n-[4-(4-ethoxyphenylazo) phenoxy]alkyl methacrylates with varying methylene groups (n=0, 2, 6) were used to synthesize a series of azobenzene-containing amphiphilic triblock copolymers PAnC-PEG-PAnC by atom transfer radical polymerization (ATRP). Differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and one-dimensional X-ray diffraction (1D WAXD) have shown that the glass transition temperatures of these copolymers decreased with increasing n, PA0C-PEG-PA0C has no mesophase, while both PA2C-PEG-PA2C and PA6C-PEGPA6C have a nematic mesophase. These differences derive from the length of spacer groups between the polymer backbone and side-chain LC monomers.
2007, 18(9): 1133-1136
doi: 10.1016/j.cclet.2007.06.021
Abstract:
Lanthanum complex supported by the heterocyclic Schiff-base ligand of N-(2-pyridyl)-3, 5-di-tert-butyl-salicylaldimine was prepared and employed for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). The polymers obtained with this initiator showed a unimodal molecular weight distribution implied that only one active species was present. Mechanism study revealed that the polymerization proceeds via acyl-oxygen bond cleavage.
Lanthanum complex supported by the heterocyclic Schiff-base ligand of N-(2-pyridyl)-3, 5-di-tert-butyl-salicylaldimine was prepared and employed for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). The polymers obtained with this initiator showed a unimodal molecular weight distribution implied that only one active species was present. Mechanism study revealed that the polymerization proceeds via acyl-oxygen bond cleavage.
2007, 18(9): 1137-1140
doi: 10.1016/j.cclet.2007.06.029
Abstract:
A novel alkoxysilyl-functionalized poly (phthalazinone ether ketone) (PPEK) was prepared for the boundary lubricant application in micro-electro-mechanical system (MEMS). The synthesis of functionalized PPEK was started from the hydroxylation of PPEK, then following with the corresponding ring-opening reaction of 3-glycidoxypropyltrimethoxysilane (GPTMS). The structures of the functional PPEK were confirmed by FTIR, 1H NMR, 29Si NMR, and UV-vis spectrum.
A novel alkoxysilyl-functionalized poly (phthalazinone ether ketone) (PPEK) was prepared for the boundary lubricant application in micro-electro-mechanical system (MEMS). The synthesis of functionalized PPEK was started from the hydroxylation of PPEK, then following with the corresponding ring-opening reaction of 3-glycidoxypropyltrimethoxysilane (GPTMS). The structures of the functional PPEK were confirmed by FTIR, 1H NMR, 29Si NMR, and UV-vis spectrum.
2007, 18(9): 1141-1144
doi: 10.1016/j.cclet.2007.07.037
Abstract:
Homopolymerization of N-pyrimidinyl acrylamide (NPA) was reported for the first time. The polymer (polyNPA) was soluble only in acidic media and fluoroalcohols, and only in fluoroalcohol was homogeneous polymerization of NPA feasible. 1H NMR analysis proved that a 1:1 H-bonding complex could be formed between NPA and α, α-bis (trifluoromethyl) phenyl propan-2-ol (BTMP). Cumyl dithiobenzoate mediated reversible addition-fragmentation chain transfer (RAFT) polymerization of NPA in BTMP was carried out. 1H NMR analyses proved that the molecular weight increased linearly with the monomer conversion. The polymer prepared in conventional solvents was atactic while in protic media the syndiotacticity was slightly enhanced.
Homopolymerization of N-pyrimidinyl acrylamide (NPA) was reported for the first time. The polymer (polyNPA) was soluble only in acidic media and fluoroalcohols, and only in fluoroalcohol was homogeneous polymerization of NPA feasible. 1H NMR analysis proved that a 1:1 H-bonding complex could be formed between NPA and α, α-bis (trifluoromethyl) phenyl propan-2-ol (BTMP). Cumyl dithiobenzoate mediated reversible addition-fragmentation chain transfer (RAFT) polymerization of NPA in BTMP was carried out. 1H NMR analyses proved that the molecular weight increased linearly with the monomer conversion. The polymer prepared in conventional solvents was atactic while in protic media the syndiotacticity was slightly enhanced.
2007, 18(9): 1145-1147
doi: 10.1016/j.cclet.2007.06.027
Abstract:
Three new N-alkylsulfonamide-containing phenylazopyrazolone dyes have been synthesized by reaction of sulfonyl chloride intermediates with different saturated aliphatic amines and their molecular structures were confirmed by FTIR, 1H NMR and MS. The dyes were applied to unmodified polypropylene fabric. These dyes showed high exhaustion as well as higher levels of fastness to washing, sublimation and rubbing compared with C. I. Disperse Yellow 16. The results showed the N-alkylsulfonamide-containing dyes were suitable for dyeing unmodified PP fiber and exhibited good color depth and fastness properties.
Three new N-alkylsulfonamide-containing phenylazopyrazolone dyes have been synthesized by reaction of sulfonyl chloride intermediates with different saturated aliphatic amines and their molecular structures were confirmed by FTIR, 1H NMR and MS. The dyes were applied to unmodified polypropylene fabric. These dyes showed high exhaustion as well as higher levels of fastness to washing, sublimation and rubbing compared with C. I. Disperse Yellow 16. The results showed the N-alkylsulfonamide-containing dyes were suitable for dyeing unmodified PP fiber and exhibited good color depth and fastness properties.
2007, 18(9): 1148-1150
doi: 10.1016/j.cclet.2007.06.032
Abstract:
A novel sulfonated diamine monomer, 1, 2-dihydro-2-(3-sulfonic-4-aminophenyl)-4-[4-(4-aminophenoxy)-phenyl]phthalazinl-one (S-DHPZDA), was successfully synthesized by direct sulfonation of diamine 1, 2-dihydro-2-(4-aminophenyl)-4-[4-(4-aminophenoxy)-phenyl]-phthalazin-1-one (DHPZDA). A series of sulfonated polyimides (SPIs), which can be used as the material of the proton exchange membrane (PEM) for the proton exchange membrane fuel cell (PEMFC), were prepared from 1, 4, 5, 8-naphthalenetetracarboxylic dianhydride (NTDA), S-DHPZDA, and nonsulfonated diamines DHPZDA. The structure of the monomer and polymers were characterized by FT-IR and 1H NMR. The solubility of the S-DHPZDA-based SPIs has been improved due to the induction of the phthalazione moiety. The SPIs membranes have high thermo-stability, predominant swelling resistance with high ion exchange capacity.
A novel sulfonated diamine monomer, 1, 2-dihydro-2-(3-sulfonic-4-aminophenyl)-4-[4-(4-aminophenoxy)-phenyl]phthalazinl-one (S-DHPZDA), was successfully synthesized by direct sulfonation of diamine 1, 2-dihydro-2-(4-aminophenyl)-4-[4-(4-aminophenoxy)-phenyl]-phthalazin-1-one (DHPZDA). A series of sulfonated polyimides (SPIs), which can be used as the material of the proton exchange membrane (PEM) for the proton exchange membrane fuel cell (PEMFC), were prepared from 1, 4, 5, 8-naphthalenetetracarboxylic dianhydride (NTDA), S-DHPZDA, and nonsulfonated diamines DHPZDA. The structure of the monomer and polymers were characterized by FT-IR and 1H NMR. The solubility of the S-DHPZDA-based SPIs has been improved due to the induction of the phthalazione moiety. The SPIs membranes have high thermo-stability, predominant swelling resistance with high ion exchange capacity.
2007, 18(9): 1151-1153
doi: 10.1016/j.cclet.2007.07.031
Abstract:
Attempts were made to develop dyes with high affinity for polylactide as an alternative to the existent commercial disperse dyes. The dyes synthesized according to the affinity concept of dye to polylactide exhibited excellent dyeing properties on polylactide compared with the commercial disperse dyes.
Attempts were made to develop dyes with high affinity for polylactide as an alternative to the existent commercial disperse dyes. The dyes synthesized according to the affinity concept of dye to polylactide exhibited excellent dyeing properties on polylactide compared with the commercial disperse dyes.
2007, 18(9): 1154-1158
doi: 10.1016/j.cclet.2007.07.002
Abstract:
In this paper five equations of state are tested for checking their ability to predict the Joule-Thomson inversion curve. These five equations of state are:Mohsennia-Modarres-Mansoori (MMM), Ji-Lemp (JL), modified Soave-Redlich-Kwang (SRK) equation of state by Graboski (MSRK1), modified SRK equation of state by Peneloux and Rauzy (MSRK2), and modified Peng-Robinson (PR) equation of state by Rauzy (PRmr). The investigated equations of state give good prediction of the low-temperature branch of the inversion curve, except for MMM equation of state. The high-temperature branch and the peak of the inversion curve have been observed, in general, to be sensitive to the applied equation of state. The values of the maximum inversion temperature and maximum inversion pressure are calculated for each component used in this work.
In this paper five equations of state are tested for checking their ability to predict the Joule-Thomson inversion curve. These five equations of state are:Mohsennia-Modarres-Mansoori (MMM), Ji-Lemp (JL), modified Soave-Redlich-Kwang (SRK) equation of state by Graboski (MSRK1), modified SRK equation of state by Peneloux and Rauzy (MSRK2), and modified Peng-Robinson (PR) equation of state by Rauzy (PRmr). The investigated equations of state give good prediction of the low-temperature branch of the inversion curve, except for MMM equation of state. The high-temperature branch and the peak of the inversion curve have been observed, in general, to be sensitive to the applied equation of state. The values of the maximum inversion temperature and maximum inversion pressure are calculated for each component used in this work.
2007, 18(9): 1159-1162
doi: 10.1016/j.cclet.2007.07.001
Abstract:
The ONIOM quantum mechanics method is used to study the reaction of one-carbon unit transfer from an imidazolidine to 6-aminouracil model with the participation of water molecules. The computation results show that in this reactionthe participation of H2O molecule makes the energy barrier lower because of the H-bond interaction.
The ONIOM quantum mechanics method is used to study the reaction of one-carbon unit transfer from an imidazolidine to 6-aminouracil model with the participation of water molecules. The computation results show that in this reactionthe participation of H2O molecule makes the energy barrier lower because of the H-bond interaction.
