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2010 Volume 21 Issue 1
2010, 21(1): 1-4
doi: 10.1016/j.cclet.2009.09.002
Abstract:
Some new 2-aryl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-ones have been prepared through cyclocondensation of 2-amino 1H-pyrrole-3-carboxamides with aromatic aldehydes followed by air oxidation in the presence of 3-methyl-l-(4-sulfonic acid)butylimidazolium hydrogen sulfate [(CH2)4SO3HMIMJ[HSO4], a Brφnsted-acidic ionic liquid, as a green and reusable catalyst in solvent-free conditions.
Some new 2-aryl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-ones have been prepared through cyclocondensation of 2-amino 1H-pyrrole-3-carboxamides with aromatic aldehydes followed by air oxidation in the presence of 3-methyl-l-(4-sulfonic acid)butylimidazolium hydrogen sulfate [(CH2)4SO3HMIMJ[HSO4], a Brφnsted-acidic ionic liquid, as a green and reusable catalyst in solvent-free conditions.
2010, 21(1): 5-8
doi: 10.1016/j.cclet.2009.07.020
Abstract:
A facile and convenient protocol was developed for the synthesis of 1,5-diarylpyrazoles using Baylis-Hillman adducts in the presence of HY-zeolite as an efficient recyclable heterogeneous catalyst in reasonable reaction times (1.5-2.5 h) and high yields (78-90%).
A facile and convenient protocol was developed for the synthesis of 1,5-diarylpyrazoles using Baylis-Hillman adducts in the presence of HY-zeolite as an efficient recyclable heterogeneous catalyst in reasonable reaction times (1.5-2.5 h) and high yields (78-90%).
2010, 21(1): 9-12
doi: 10.1016/j.cclet.2009.07.003
Abstract:
A novel carbazole-based compound 5, 3,6-bis[(N-ethylcarbazole-3-yl)-propene-l-keto]-N-ethylcarbazole has been designed, synthesized and characterized. The absorption and fluorescence spectra in solvents of different polarities prove that the compound has a distinct intramolecular charge transfer character. Compound 5 can be used as a new class of fluorescent probe or biosensor due to its sensitivity to the local microenvironment such as solvent polarity.
A novel carbazole-based compound 5, 3,6-bis[(N-ethylcarbazole-3-yl)-propene-l-keto]-N-ethylcarbazole has been designed, synthesized and characterized. The absorption and fluorescence spectra in solvents of different polarities prove that the compound has a distinct intramolecular charge transfer character. Compound 5 can be used as a new class of fluorescent probe or biosensor due to its sensitivity to the local microenvironment such as solvent polarity.
2010, 21(1): 13-17
doi: 10.1016/j.cclet.2009.08.002
Abstract:
Six new polyesters 7a-f were synthesized through the solution polycondensation reaction of diacid chloride 5 with six aromatic diols 6a-f in N,N-dimethyl acetamide (DMAc) as solvent in the presence of pyridine as base. The polycondensation reaction produced a series of novel polyester containing pyridyl moiety in the main chain in high yields with inherent viscosities between 0.35 and 0.54 dL/g. The resulted polymers were fully characterized by means of FT-IR spectroscopy, elemental analyses, inherent viscosity and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis (TGA) and differentional thermal gravimetric (DTG). The glass-transition temperatures of these polyesters were recorded between 130 and 170℃ by differential scanning calorimetry (DSC) and the 10% weight loss temperatures were ranging from 390 to 450℃ under nitrogen.
Six new polyesters 7a-f were synthesized through the solution polycondensation reaction of diacid chloride 5 with six aromatic diols 6a-f in N,N-dimethyl acetamide (DMAc) as solvent in the presence of pyridine as base. The polycondensation reaction produced a series of novel polyester containing pyridyl moiety in the main chain in high yields with inherent viscosities between 0.35 and 0.54 dL/g. The resulted polymers were fully characterized by means of FT-IR spectroscopy, elemental analyses, inherent viscosity and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis (TGA) and differentional thermal gravimetric (DTG). The glass-transition temperatures of these polyesters were recorded between 130 and 170℃ by differential scanning calorimetry (DSC) and the 10% weight loss temperatures were ranging from 390 to 450℃ under nitrogen.
2010, 21(1): 18-22
doi: 10.1016/j.cclet.2009.08.004
Abstract:
A highly efficient and selective [2+2+2] cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent, affording isoindolines and isobenzofurans in good to excellent yields. The center atoms (N, O) in the diynes showed a significant effect for the cyclization.
A highly efficient and selective [2+2+2] cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent, affording isoindolines and isobenzofurans in good to excellent yields. The center atoms (N, O) in the diynes showed a significant effect for the cyclization.
2010, 21(1): 23-26
doi: 10.1016/j.cclet.2009.08.005
Abstract:
A novel tripodal receptor, l,3,5-tri((5,7-dimethyl-l,8-naphthyridin-2-yl-amino)methyl)-2,4,6-triethylbenzene (1) was synthesized from starting materials 2,6-diamino-pyridine (2) and 1,3,5-triethylbenzene (4) by three steps with an overall yield of 25%, and characterized by ESI-MS, FT-ER and 1H NMR spectra. Additionally, its absorption and emission spectra were investigated.
A novel tripodal receptor, l,3,5-tri((5,7-dimethyl-l,8-naphthyridin-2-yl-amino)methyl)-2,4,6-triethylbenzene (1) was synthesized from starting materials 2,6-diamino-pyridine (2) and 1,3,5-triethylbenzene (4) by three steps with an overall yield of 25%, and characterized by ESI-MS, FT-ER and 1H NMR spectra. Additionally, its absorption and emission spectra were investigated.
2010, 21(1): 27-30
doi: 10.1016/j.cclet.2009.08.007
Abstract:
Fatty acid modified glucagon-like peptide-1(7-36) amide was synthesized efficiently on Rink-Amide-MBHA resin by microwave-assisted solid phase method. The method of thermal and controlled microwave irradiation provided impressive enhancements in product yield, selectivity, and reaction rate. The coupling time was dramatically decreased to 6 min, and the desired products were obtained in high yield and purity.
Fatty acid modified glucagon-like peptide-1(7-36) amide was synthesized efficiently on Rink-Amide-MBHA resin by microwave-assisted solid phase method. The method of thermal and controlled microwave irradiation provided impressive enhancements in product yield, selectivity, and reaction rate. The coupling time was dramatically decreased to 6 min, and the desired products were obtained in high yield and purity.
2010, 21(1): 31-34
doi: 10.1016/j.cclet.2009.08.011
Abstract:
Cerium trichloride heptahydrate (CeCl3·7H2O) was found to be an efficient and recyclable catalyst for the three-component direct Mannich reaction of anilines and benzaldehydes with acetophenone. This protocol has advantages of high yield, no environmental pollution, mild condition, and simple work-up procedure.
Cerium trichloride heptahydrate (CeCl3·7H2O) was found to be an efficient and recyclable catalyst for the three-component direct Mannich reaction of anilines and benzaldehydes with acetophenone. This protocol has advantages of high yield, no environmental pollution, mild condition, and simple work-up procedure.
2010, 21(1): 35-38
doi: 10.1016/j.cclet.2009.09.012
Abstract:
A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under microwave irradiation.
A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under microwave irradiation.
2010, 21(1): 39-42
doi: 10.1016/j.cclet.2009.07.010
Abstract:
Heterogeneous catalyst aluminium oxide (acidic) is found to be an effective catalyst for the solvent-free condensation reaction of indole with aldehydes in microwave irradiation with shorter reaction time and higher yields.
Heterogeneous catalyst aluminium oxide (acidic) is found to be an effective catalyst for the solvent-free condensation reaction of indole with aldehydes in microwave irradiation with shorter reaction time and higher yields.
2010, 21(1): 43-46
doi: 10.1016/j.cclet.2009.07.017
Abstract:
Some of the substituted anilines were selectively converted in to the corresponding azoxy and azobenzenes by oxidation with 30% aqueous hydrogen peroxide. The reactions were catalyzed by various heteropolyoxometalates, at boiling point of the used solvents. An improvement in the product yield and selectivity towards azoxybenzens was also observed. Azobenzenes was obtained as by-product. In the all similar cases, the highest yield of azoxy compounds was observed using K5PW11ZnO39 as catalyst in N,N dimethylformamide solvent.
Some of the substituted anilines were selectively converted in to the corresponding azoxy and azobenzenes by oxidation with 30% aqueous hydrogen peroxide. The reactions were catalyzed by various heteropolyoxometalates, at boiling point of the used solvents. An improvement in the product yield and selectivity towards azoxybenzens was also observed. Azobenzenes was obtained as by-product. In the all similar cases, the highest yield of azoxy compounds was observed using K5PW11ZnO39 as catalyst in N,N dimethylformamide solvent.
2010, 21(1): 47-50
doi: 10.1016/j.cclet.2009.07.018
Abstract:
A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described. A variety of aliphatic and aromatic aldehydes, ketones and amines when mixed with NaBH4/silica chloride at room temperature, afforded excellent yield of the corresponding amines.
A simple and convenient procedure for the preparation of amines from aldehydes and ketones with sodium borohydride activated by silica chloride as a catalyst under solvent-free conditions is described. A variety of aliphatic and aromatic aldehydes, ketones and amines when mixed with NaBH4/silica chloride at room temperature, afforded excellent yield of the corresponding amines.
2010, 21(1): 51-54
doi: 10.1016/j.cclet.2009.08.012
Abstract:
Iminodiacetic acid resin-chelated copper(Ⅱ) complex is effective in cross-coupling reactions between azaheterocycles and aryl or heteroaryl halides, providing N>-arylated products in good to excellent yields. The copper catalyst is air stable and can be readily recovered and reused with minimal loss of activity for three runs
Iminodiacetic acid resin-chelated copper(Ⅱ) complex is effective in cross-coupling reactions between azaheterocycles and aryl or heteroaryl halides, providing N>-arylated products in good to excellent yields. The copper catalyst is air stable and can be readily recovered and reused with minimal loss of activity for three runs
2010, 21(1): 55-58
doi: 10.1016/j.cclet.2009.07.011
Abstract:
A series of novel 7-(4-alkoxyimino-3-hydroxypiperidin-l-yl)quinolone derivatives were designed, synthesized and evaluated for in vitro antibacterial activities. Compounds 8f, 8g, 8i and 8j with the potencies similar to or better than those of levofloxacin and IMB against Staphylococcus aureus and Staphylococcus epidermidis, worth further investigation.
A series of novel 7-(4-alkoxyimino-3-hydroxypiperidin-l-yl)quinolone derivatives were designed, synthesized and evaluated for in vitro antibacterial activities. Compounds 8f, 8g, 8i and 8j with the potencies similar to or better than those of levofloxacin and IMB against Staphylococcus aureus and Staphylococcus epidermidis, worth further investigation.
2010, 21(1): 59-62
doi: 10.1016/j.cclet.2009.08.017
Abstract:
A series of monosubstituted troxerutin esters have been synthesized by enzyme-catalyzed regioselective acylation of troxerutin in nonaqueous medium. Using divinyl dicarboxylates (CH2=CH-OOC-(CH2)n-COO-CH=CH2, n=2, 3, 4, 7, 8, 11) featuring different chain length as acyl donors and alkaline protease from Bacillus subtilis as catalyst, troxerutin was regioselective acylated at B' ethoxyl group. The results indicated that the regioselectivity of the enzyme-catalyzed acylation was not affected by the chain length of the acyl donor.
A series of monosubstituted troxerutin esters have been synthesized by enzyme-catalyzed regioselective acylation of troxerutin in nonaqueous medium. Using divinyl dicarboxylates (CH2=CH-OOC-(CH2)n-COO-CH=CH2, n=2, 3, 4, 7, 8, 11) featuring different chain length as acyl donors and alkaline protease from Bacillus subtilis as catalyst, troxerutin was regioselective acylated at B' ethoxyl group. The results indicated that the regioselectivity of the enzyme-catalyzed acylation was not affected by the chain length of the acyl donor.
2010, 21(1): 63-66
doi: 10.1016/j.cclet.2009.09.006
Abstract:
A series of new 4-substituted benzoxazolone derivatives were synthesized according to a convenient method, their anti inflammatory and analgesic activities in vivo were evaluated. All of them were new compounds, the structures of all the synthesized compounds were confirmed by 1H NMR, 13C NMR, ESI-MS and HR-MS. Most of the compounds exhibited anti-inflammatory activity.
A series of new 4-substituted benzoxazolone derivatives were synthesized according to a convenient method, their anti inflammatory and analgesic activities in vivo were evaluated. All of them were new compounds, the structures of all the synthesized compounds were confirmed by 1H NMR, 13C NMR, ESI-MS and HR-MS. Most of the compounds exhibited anti-inflammatory activity.
2010, 21(1): 67-69
doi: 10.1016/j.cclet.2009.08.009
Abstract:
A convenient method for the synthesis of ezetimibe analogs as cholesterol absorption inhibitors was described. The key step in the synthesis was the intramolecular ring formation through Mitsunobu reaction. Furthermore, a new series of analogs was designed and synthesized.
A convenient method for the synthesis of ezetimibe analogs as cholesterol absorption inhibitors was described. The key step in the synthesis was the intramolecular ring formation through Mitsunobu reaction. Furthermore, a new series of analogs was designed and synthesized.
2010, 21(1): 70-72
doi: 10.1016/j.cclet.2009.08.006
Abstract:
A new heterocyclic compound, named 5,5'-diisobutoxy-2,2'-bifuran (1), and four known compounds (2-5) were isolated from the roots of Cyathula officinalis Kuan. Their structures were elucidated by spectroscopic methods. Among these compounds, 5,5'-dibutoxy-2,2'-bifuran (2) was isolated for the first time from this plant.
A new heterocyclic compound, named 5,5'-diisobutoxy-2,2'-bifuran (1), and four known compounds (2-5) were isolated from the roots of Cyathula officinalis Kuan. Their structures were elucidated by spectroscopic methods. Among these compounds, 5,5'-dibutoxy-2,2'-bifuran (2) was isolated for the first time from this plant.
2010, 21(1): 73-75
doi: 10.1016/j.cclet.2009.09.013
Abstract:
A new jatrophane-type diterpenoid, 7β, 14β,15β-triacetoxy-3β-benzoyloxy-9-oxojatropha-5E,11E-diene, named euphornin N was isolated from Euphorbia helioscopia L. The structure and relative stereochemistry of the new compound was elucidated by spectroscopic methods.
A new jatrophane-type diterpenoid, 7β, 14β,15β-triacetoxy-3β-benzoyloxy-9-oxojatropha-5E,11E-diene, named euphornin N was isolated from Euphorbia helioscopia L. The structure and relative stereochemistry of the new compound was elucidated by spectroscopic methods.
2010, 21(1): 76-80
doi: 10.1016/j.cclet.2009.08.015
Abstract:
Microbial transformation of diosgenin (1) by Syncephalastrum racemosum yielded five new polar metabolites, which were identified as (25R)-spirost-5-en-3β,7α,9α-triol-12-one (2), (25R)-spirost-5-en-3β,9α,12α-triol-7-one (3), (25R)-spirost-5-en-3β,9α-diol-7,12-dione(4), (25R)-spirost-4-en-9α,12β,14α-triol-3-one(5), and (25S)-spirost-4-en-9α,14α,25β-triol-3-one (6). Compounds 1-6 exhibited moderate cytotoxicity against K562 cells and among them compounds 2, 3, and 6 were more potent than the parent compound 1.
Microbial transformation of diosgenin (1) by Syncephalastrum racemosum yielded five new polar metabolites, which were identified as (25R)-spirost-5-en-3β,7α,9α-triol-12-one (2), (25R)-spirost-5-en-3β,9α,12α-triol-7-one (3), (25R)-spirost-5-en-3β,9α-diol-7,12-dione(4), (25R)-spirost-4-en-9α,12β,14α-triol-3-one(5), and (25S)-spirost-4-en-9α,14α,25β-triol-3-one (6). Compounds 1-6 exhibited moderate cytotoxicity against K562 cells and among them compounds 2, 3, and 6 were more potent than the parent compound 1.
2010, 21(1): 81-84
doi: 10.1016/j.cclet.2009.09.009
Abstract:
Two new 19-oxygenated ent-kaurane diterpenoids, pharicinins D and E (1 and 2), together with an artifact, pharicinin D acetal (3) were isolated from the leaves of Isodon pharicus. Their structures were determined by 1D and 2D NMR spectroscopic analysis. All of them were evaluated for their cytotoxicity.
Two new 19-oxygenated ent-kaurane diterpenoids, pharicinins D and E (1 and 2), together with an artifact, pharicinin D acetal (3) were isolated from the leaves of Isodon pharicus. Their structures were determined by 1D and 2D NMR spectroscopic analysis. All of them were evaluated for their cytotoxicity.
2010, 21(1): 85-88
doi: 10.1016/j.cclet.2009.08.010
Abstract:
Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) is an excellent marker of oxidative DNA damage. In this study, employing guanosine as dummy template a novel molecularly imprinted (MIP) monolithic capillary column had been synthesized, and that was used as medium of in-tube solid phase microextraction (SPME). Coupled with capillary electrophoresis-electrochemical detection (CE-ECD), the system of extraction and detection of 8-OHdG in urinary sample had been developed. Because of its greater phase ratio combined with convective mass transfer and inherent selectivity, the MIP monolithic column exhibited high extraction efficiency on target analyte with the limit of detection (LOD) and quantity (LOQ) reached 2.6 nmol/L (S/N=3) and 8.6nmol/L (S/N=10), respectively. The linear range was from 10 nmol/L to 1.5μ-mol/L (r=0.9999) with relative standard deviation (RSD) 3.7% for peak current, and 0.5% for migration time, and the average recovery of spiked 20-200 nmol/L 8-OHdG was 85%±3.5% (n=6). This highly sensitive method was applied to analysis of 8-OHdG in urinary samples from healthy volunteers, coking plant workers and lung cancer patients.
Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) is an excellent marker of oxidative DNA damage. In this study, employing guanosine as dummy template a novel molecularly imprinted (MIP) monolithic capillary column had been synthesized, and that was used as medium of in-tube solid phase microextraction (SPME). Coupled with capillary electrophoresis-electrochemical detection (CE-ECD), the system of extraction and detection of 8-OHdG in urinary sample had been developed. Because of its greater phase ratio combined with convective mass transfer and inherent selectivity, the MIP monolithic column exhibited high extraction efficiency on target analyte with the limit of detection (LOD) and quantity (LOQ) reached 2.6 nmol/L (S/N=3) and 8.6nmol/L (S/N=10), respectively. The linear range was from 10 nmol/L to 1.5μ-mol/L (r=0.9999) with relative standard deviation (RSD) 3.7% for peak current, and 0.5% for migration time, and the average recovery of spiked 20-200 nmol/L 8-OHdG was 85%±3.5% (n=6). This highly sensitive method was applied to analysis of 8-OHdG in urinary samples from healthy volunteers, coking plant workers and lung cancer patients.
2010, 21(1): 89-92
doi: 10.1016/j.cclet.2009.08.014
Abstract:
Comparison in electron transfer (ET) processes from decamethyferrocene (DMFe) in nitrobenzene (NB) to ferric ion in aqueous phase was investigated for the first time by the scanning electrochemical microscopy (SECM). As compared with the system of Fe(CN)63--DMFe, the ET rate obtained from Fe3+-DMFe was lower in spite of larger driving force, which may arise from the effect of reorganization energy. Otherwise, the effect of common ion on rate constants was also probed and results suggested additional complexity of the ET mechanism between Fe(CN)63-and DMFe.
Comparison in electron transfer (ET) processes from decamethyferrocene (DMFe) in nitrobenzene (NB) to ferric ion in aqueous phase was investigated for the first time by the scanning electrochemical microscopy (SECM). As compared with the system of Fe(CN)63--DMFe, the ET rate obtained from Fe3+-DMFe was lower in spite of larger driving force, which may arise from the effect of reorganization energy. Otherwise, the effect of common ion on rate constants was also probed and results suggested additional complexity of the ET mechanism between Fe(CN)63-and DMFe.
2010, 21(1): 93-96
doi: 10.1016/j.cclet.2009.09.010
Abstract:
Poly-L-lysine (PLL) was first electrodeposited onto the surface of a glassy carbon (GC) electrode. The PLL modified electrode was used to immobilize chloroperoxidase (CPO) via l-[(3-dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDC). The electrochemical behaviors of immobilized CPO on PLL/GC electrode were investigated by cyclic voltammetry (CV). The CV results obtained showed that CPO was successfully immobilized on the PLL/GC electrode and a fast direct electron transfer between CPO and PLL-GC electrode was achieved with a formal redox potential of-0.23 V vs. SCE. The CPO-PLL/GC modified electrode showed a good catalytic activity for electrocatalytical reduction of O2, promising for a broad range of CPO-catalyzed transformations.
Poly-L-lysine (PLL) was first electrodeposited onto the surface of a glassy carbon (GC) electrode. The PLL modified electrode was used to immobilize chloroperoxidase (CPO) via l-[(3-dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDC). The electrochemical behaviors of immobilized CPO on PLL/GC electrode were investigated by cyclic voltammetry (CV). The CV results obtained showed that CPO was successfully immobilized on the PLL/GC electrode and a fast direct electron transfer between CPO and PLL-GC electrode was achieved with a formal redox potential of-0.23 V vs. SCE. The CPO-PLL/GC modified electrode showed a good catalytic activity for electrocatalytical reduction of O2, promising for a broad range of CPO-catalyzed transformations.
2010, 21(1): 97-100
doi: 10.1016/j.cclet.2009.08.013
Abstract:
A series of linear and V-shaped oligo(phenylene ethynylene) derivatives 1-3 were synthesized through sequent Sonogashira coupling and propargyl alcohol deprotection reaction in high yields. The alkoxy chains (i.e., n-hexyloxy groups) were introduced to assure good solubility of compounds 1-3 in common solvents. The photophysical properties of 1-3 in solution depend strongly on the geometries of these compounds.
A series of linear and V-shaped oligo(phenylene ethynylene) derivatives 1-3 were synthesized through sequent Sonogashira coupling and propargyl alcohol deprotection reaction in high yields. The alkoxy chains (i.e., n-hexyloxy groups) were introduced to assure good solubility of compounds 1-3 in common solvents. The photophysical properties of 1-3 in solution depend strongly on the geometries of these compounds.
2010, 21(1): 101-104
doi: 10.1016/j.cclet.2009.08.001
Abstract:
In this study, advanced oxidation processes (AOPs) such as anodic oxidation (AO), UV/H2O2 and Fenton processes (FP) were investigated for the degradation of salicylic acid (SA) in lab-scale experiments. Boron-doped diamond (BDD) film electrodes using Ta as substrates were employed for AO of SA. In the case of FP and UV/H2O2, most favorable experimental conditions were determined for each process and these were used for comparing with AO process. The study showed that the FP was the most effective process under acidic conditions, leading to the highest rate of SA degradation in a very short time interval. However, the results showed that Ta/BDD films had high electrocatalytic activity for complete degradation of S A; even if it employs more time for complete elimination of the S A respect to FP. Additionally, AO led to a sixfold acceleration of the oxidation rate compared with the UV/H2O2 process. Finally a rough comparison of the specific energy consumption shows that AO process reduced the energy consumption by at least 90% compared with the UV/H2O2 process.
In this study, advanced oxidation processes (AOPs) such as anodic oxidation (AO), UV/H2O2 and Fenton processes (FP) were investigated for the degradation of salicylic acid (SA) in lab-scale experiments. Boron-doped diamond (BDD) film electrodes using Ta as substrates were employed for AO of SA. In the case of FP and UV/H2O2, most favorable experimental conditions were determined for each process and these were used for comparing with AO process. The study showed that the FP was the most effective process under acidic conditions, leading to the highest rate of SA degradation in a very short time interval. However, the results showed that Ta/BDD films had high electrocatalytic activity for complete degradation of S A; even if it employs more time for complete elimination of the S A respect to FP. Additionally, AO led to a sixfold acceleration of the oxidation rate compared with the UV/H2O2 process. Finally a rough comparison of the specific energy consumption shows that AO process reduced the energy consumption by at least 90% compared with the UV/H2O2 process.
2010, 21(1): 105-108
doi: 10.1016/j.cclet.2009.07.015
Abstract:
A novel class of α-linolenic acid-in-water microemulsion free of co-surfactant was investigated as potential food delivery systems. Rough demarcation within the transparent region was deduced from the results of conductivity and polarizing optical microscopy. The microemulsion mean hydrodynamic diameter and characterization were determined by dynamic light scattering and negative-staining TEM. The location of ALA molecules in the microemulsion formulations was determined by 1H NMR spectroscopy.
A novel class of α-linolenic acid-in-water microemulsion free of co-surfactant was investigated as potential food delivery systems. Rough demarcation within the transparent region was deduced from the results of conductivity and polarizing optical microscopy. The microemulsion mean hydrodynamic diameter and characterization were determined by dynamic light scattering and negative-staining TEM. The location of ALA molecules in the microemulsion formulations was determined by 1H NMR spectroscopy.
2010, 21(1): 109-112
doi: 10.1016/j.cclet.2009.08.008
Abstract:
Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface. The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles. Furthermore, enhanced absorption was also observed for the same system. Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at room temperature, as well as to increase the excitation rate of lumophores at room temperature.
Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface. The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles. Furthermore, enhanced absorption was also observed for the same system. Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at room temperature, as well as to increase the excitation rate of lumophores at room temperature.
2010, 21(1): 113-116
doi: 10.1016/j.cclet.2009.09.008
Abstract:
The origin of homochirality in living organisms is controversial, stands out of being particularly important and a question which is still not satisfactorily answered. A mental picture of sequence of events that is thought to have preceded the existence of chirality in molecules is described. A chemical model to mimic the original abiotic conditions in an attempt to explain the preference of homochirality in living systems was tried. The effect which might have influenced this preference is presented. The surprising and unexpected results are indeed interesting, significant, repeatable and indicate that complexing alanine with nickel(Ⅱ) ion alters the racemization rates of d and l isomers of the amino acid. However, why this difference happens is unclear and is difficult to explain.
The origin of homochirality in living organisms is controversial, stands out of being particularly important and a question which is still not satisfactorily answered. A mental picture of sequence of events that is thought to have preceded the existence of chirality in molecules is described. A chemical model to mimic the original abiotic conditions in an attempt to explain the preference of homochirality in living systems was tried. The effect which might have influenced this preference is presented. The surprising and unexpected results are indeed interesting, significant, repeatable and indicate that complexing alanine with nickel(Ⅱ) ion alters the racemization rates of d and l isomers of the amino acid. However, why this difference happens is unclear and is difficult to explain.
2010, 21(1): 117-121
doi: 10.1016/j.cclet.2009.06.038
Abstract:
Nitrogen-doped TiO2 nanophotocatalysts were prepared, and characterized by XRD patterns and UV-vis spectroscopy. The results indicated that nitrogen was doped effectively and the shift of the absorption edge to a lower energy and a stronger absorption in the visible light region were observed. The calcinations temperature is a key factor to narrow the band gap of titania, and consequently affects the response to visible light of nitrogen-doped TiO2 nanocrystals. This photocatalyst can effectively inhibit the growth of Helminthosporium maydis, whereas undoped TiO2 nanocrystals cannot inhibit the growth of H. maydis under the same experimental conditions.
Nitrogen-doped TiO2 nanophotocatalysts were prepared, and characterized by XRD patterns and UV-vis spectroscopy. The results indicated that nitrogen was doped effectively and the shift of the absorption edge to a lower energy and a stronger absorption in the visible light region were observed. The calcinations temperature is a key factor to narrow the band gap of titania, and consequently affects the response to visible light of nitrogen-doped TiO2 nanocrystals. This photocatalyst can effectively inhibit the growth of Helminthosporium maydis, whereas undoped TiO2 nanocrystals cannot inhibit the growth of H. maydis under the same experimental conditions.
2010, 21(1): 122-126
doi: 10.1016/j.cclet.2009.08.003
Abstract:
A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere. The rice husk substrate consists of porous activated carbon and silica, where spinel ferrite particles with average diameter of 59 nm are distributed. The surface area of the composite is greater than 170 m2 g-1 and the bulk density is less than 0.6 g cm-3. Inert atmosphere is indispensable for the synthesis of pure ferrite composites, while different preparation temperatures of above 600℃ result in composites with similar structures and morphologies. Due to the presence of ferrite particles, this novel composite shows enhanced adsorption ability for acid orange Ⅱ.
A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere. The rice husk substrate consists of porous activated carbon and silica, where spinel ferrite particles with average diameter of 59 nm are distributed. The surface area of the composite is greater than 170 m2 g-1 and the bulk density is less than 0.6 g cm-3. Inert atmosphere is indispensable for the synthesis of pure ferrite composites, while different preparation temperatures of above 600℃ result in composites with similar structures and morphologies. Due to the presence of ferrite particles, this novel composite shows enhanced adsorption ability for acid orange Ⅱ.
