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2011 Volume 22 Issue 8
2011, 22(8): 883-886
doi: 10.1016/j.cclet.2011.03.002
Abstract:
A series of novel 5-benzylidene-3-(3-fluoro-4-yl-morpholin-4-yl-phenylimino)thiazolidin-4-one derivatives were synthesized using [bmIm]OH as a catalyst and were tested for their antibacterial and antifungal activities. These compounds showed moderate in vitro activities against the microorganisms tested.
A series of novel 5-benzylidene-3-(3-fluoro-4-yl-morpholin-4-yl-phenylimino)thiazolidin-4-one derivatives were synthesized using [bmIm]OH as a catalyst and were tested for their antibacterial and antifungal activities. These compounds showed moderate in vitro activities against the microorganisms tested.
2011, 22(8): 887-890
doi: 10.1016/j.cclet.2011.01.030
1
Abstract:
A series of bis-quaternary ammonium compounds (bis-QACs) N, N'-hexamethylenebis(1-alkyl-4-carbamoyl pyridinium bromide) (4BCAP-6, n) (alkyl chain length, n=8, 10, 12, 14, 16 and 18) were synthesized and characterized. Their surface tensions, critical micelle concentrations (CMC), and antimicrobial activities were evaluated. 4BCAP-6. 10 exhibited the strongest antimicrobial activities except for that against Proteus vulgari. The activities of 4BCAP-6, n against Escherichia colt zk126 were not significantly influenced by temperature. pH and initial bacteria concentration. These results indicate that bis-QACs exhibit high antimicrobial activity regardless of the environmental conditions.
A series of bis-quaternary ammonium compounds (bis-QACs) N, N'-hexamethylenebis(1-alkyl-4-carbamoyl pyridinium bromide) (4BCAP-6, n) (alkyl chain length, n=8, 10, 12, 14, 16 and 18) were synthesized and characterized. Their surface tensions, critical micelle concentrations (CMC), and antimicrobial activities were evaluated. 4BCAP-6. 10 exhibited the strongest antimicrobial activities except for that against Proteus vulgari. The activities of 4BCAP-6, n against Escherichia colt zk126 were not significantly influenced by temperature. pH and initial bacteria concentration. These results indicate that bis-QACs exhibit high antimicrobial activity regardless of the environmental conditions.
2011, 22(8): 891-894
doi: 10.1016/j.cclet.2010.12.053
Abstract:
Several 2,5-dimethyl-N-substituted pyrroles were prepared by the condensation of different substituted anilines with 2,5-hexanedione using nano lead oxide as an efficient and recyclable catalyst. All the synthesized compounds are confirmed through IR, 1H NMR, 13C NMR and mass spectral data. Nano lead oxide β-PbO (P85) was prepared by dissolving lead acetate dihydrate in 1-propanol at a pH 9.0 under stirring at 85 ℃. The structural study and surface morphology of the lead oxide (PbO) were characterized using X-ray diffraction (XRD), Scanning electron microscopy (SEM) and the functional groups of the PbO sample were investigated using infrared spectrophotometer.
Several 2,5-dimethyl-N-substituted pyrroles were prepared by the condensation of different substituted anilines with 2,5-hexanedione using nano lead oxide as an efficient and recyclable catalyst. All the synthesized compounds are confirmed through IR, 1H NMR, 13C NMR and mass spectral data. Nano lead oxide β-PbO (P85) was prepared by dissolving lead acetate dihydrate in 1-propanol at a pH 9.0 under stirring at 85 ℃. The structural study and surface morphology of the lead oxide (PbO) were characterized using X-ray diffraction (XRD), Scanning electron microscopy (SEM) and the functional groups of the PbO sample were investigated using infrared spectrophotometer.
2011, 22(8): 895-898
doi: 10.1016/j.cclet.2011.01.033
Abstract:
A novel and efficient procedure for the synthesis of alkyl phosphonates through one pot condensation of alkyl halide and tri-alkyl/aryl phosphite in the presence of Amberlyst-15 as catalyst under solvent free conditions was applied. It demonstrated several advantages such as good yields of products, simple operation, convenient separation and inexpensive catalyst.
A novel and efficient procedure for the synthesis of alkyl phosphonates through one pot condensation of alkyl halide and tri-alkyl/aryl phosphite in the presence of Amberlyst-15 as catalyst under solvent free conditions was applied. It demonstrated several advantages such as good yields of products, simple operation, convenient separation and inexpensive catalyst.
2011, 22(8): 899-902
doi: 10.1016/j.cclet.2011.01.010
Abstract:
New pyrimidine nucleoside derivatives with nitric oxide (NO) donor were systematically synthesized. The antivirus activities of these nucleoside analogues against vesicular stomatitis virus (VSV) in Wish cell were evaluated. It was demonstrated that most of compounds had stronger antiviral acitivity than acyclovir, while their toxicities were similar or lower to acyclovir.
New pyrimidine nucleoside derivatives with nitric oxide (NO) donor were systematically synthesized. The antivirus activities of these nucleoside analogues against vesicular stomatitis virus (VSV) in Wish cell were evaluated. It was demonstrated that most of compounds had stronger antiviral acitivity than acyclovir, while their toxicities were similar or lower to acyclovir.
2011, 22(8): 903-906
doi: 10.1016/j.cclet.2010.12.030
Abstract:
We report herein the use of p-dodecylbenzenesulfonic acid (DBSA) as a catalyst for a one-pot Biginelli reaction to afford 3,4-dihydropyrimidinone derivatives in good to excellent yields. This reaction proceeds efficiently in water and under solvent free conditions. Comparisons of results indicate that although the yields are high and comparable for both methods, the reaction times are considerably shorter under solvent free conditions.
We report herein the use of p-dodecylbenzenesulfonic acid (DBSA) as a catalyst for a one-pot Biginelli reaction to afford 3,4-dihydropyrimidinone derivatives in good to excellent yields. This reaction proceeds efficiently in water and under solvent free conditions. Comparisons of results indicate that although the yields are high and comparable for both methods, the reaction times are considerably shorter under solvent free conditions.
2011, 22(8): 907-910
doi: 10.1016/j.cclet.2011.01.035
Abstract:
Analogues of endomorphin and tripeptides modified at positions 4 and 3, respectively, with various phenylalanine analogues were synthesized and their affinities for opioid receptors were evaluated. Most of the peptides exhibited potent μ-receptor affinity and selectivity, among them, compound 7 (Dmt-Pro-Tmp-Tmp-NH2) exhibited potent affinity for both μ- and δ-receptors (Kiμ=0.47 nmol/L, Kiδ=1.63 nmol/L).
Analogues of endomorphin and tripeptides modified at positions 4 and 3, respectively, with various phenylalanine analogues were synthesized and their affinities for opioid receptors were evaluated. Most of the peptides exhibited potent μ-receptor affinity and selectivity, among them, compound 7 (Dmt-Pro-Tmp-Tmp-NH2) exhibited potent affinity for both μ- and δ-receptors (Kiμ=0.47 nmol/L, Kiδ=1.63 nmol/L).
2011, 22(8): 911-914
doi: 10.1016/j.cclet.2011.01.036
Abstract:
An efficient magnesium bistrifluoromethanesulfonimide [Mg(NTf2)2] catalyzed hydroalkylation of aromatic olefins with 1,3-diketones under solvent-free conditions has been developed. The reactions proceed smoothly to give the desired products in good yields in short reaction times.
An efficient magnesium bistrifluoromethanesulfonimide [Mg(NTf2)2] catalyzed hydroalkylation of aromatic olefins with 1,3-diketones under solvent-free conditions has been developed. The reactions proceed smoothly to give the desired products in good yields in short reaction times.
2011, 22(8): 915-918
doi: 10.1016/j.cclet.2011.01.011
Abstract:
Various 1,3-oxazine derivatives were synthesized in high yields, within shorter reaction times using PEG-400 as a safer medium/ mediator. This synthetic route is exceedingly easy and avoids the use of acid/base catalysts.
Various 1,3-oxazine derivatives were synthesized in high yields, within shorter reaction times using PEG-400 as a safer medium/ mediator. This synthetic route is exceedingly easy and avoids the use of acid/base catalysts.
2011, 22(8): 919-922
doi: 10.1016/j.cclet.2011.01.037
Abstract:
Treatment of chiral N-tert-butyl sulfinylimines with ethyl bromofluoroacetate in the presence of activated Zn dust in THF afforded the α-fluoro-β-amino acid derivatives in good yields (70-86%) and moderate diastereoselectivity (66:34-92:8).
Treatment of chiral N-tert-butyl sulfinylimines with ethyl bromofluoroacetate in the presence of activated Zn dust in THF afforded the α-fluoro-β-amino acid derivatives in good yields (70-86%) and moderate diastereoselectivity (66:34-92:8).
2011, 22(8): 923-926
doi: 10.1016/j.cclet.2011.01.038
Abstract:
The asymmetric aza-Henry reaction of α-substituted nitroacetates and N-Boc imines was achieved with a new-type thiourea-guanidine bifunctional organocatalyst. The novel transformations exhibited high diastereoselectivities, and the adducts bearing adjacent quaternary and tertiary chiral centers were generally obtained in moderate to good enantioselectivities (up to 88% ee).
The asymmetric aza-Henry reaction of α-substituted nitroacetates and N-Boc imines was achieved with a new-type thiourea-guanidine bifunctional organocatalyst. The novel transformations exhibited high diastereoselectivities, and the adducts bearing adjacent quaternary and tertiary chiral centers were generally obtained in moderate to good enantioselectivities (up to 88% ee).
2011, 22(8): 927-930
doi: 10.1016/j.cclet.2011.01.012
Abstract:
An efficient method for the synthesis of 14-alkyl or aryl 14H-dibenzo[a j]xanthene derivatives by the reaction of β-naphthol, and aldehydes in the presence of a catalytic amount of bismuth(Ⅲ) chloride (BiCl3) under solvent-free conditions at 110℃ is described. Aliphatic and aromatic aldehydes were used in the reaction and in all cases the desired products were synthesized successfully. This reaction was studied under different temperatures; the maximum yield was obtained in a short reaction period at 110℃. The method offers the advantages of high yields, short reaction times, simplicity and easy workup compared to the conventional method of syntheses.
An efficient method for the synthesis of 14-alkyl or aryl 14H-dibenzo[a j]xanthene derivatives by the reaction of β-naphthol, and aldehydes in the presence of a catalytic amount of bismuth(Ⅲ) chloride (BiCl3) under solvent-free conditions at 110℃ is described. Aliphatic and aromatic aldehydes were used in the reaction and in all cases the desired products were synthesized successfully. This reaction was studied under different temperatures; the maximum yield was obtained in a short reaction period at 110℃. The method offers the advantages of high yields, short reaction times, simplicity and easy workup compared to the conventional method of syntheses.
2011, 22(8): 931-934
doi: 10.1016/j.cclet.2011.01.023
Abstract:
Tetrabutyl ammonium fluoride (TBAF) was found to be capable of catalyzing the intramolecular hydroalkoxylation of 6-hydroxyhex-2-ynoates and 7-hydroxyhept-2-ynoates. The reaction could be used to prepare 2,5-substituted THF rings and 2,6-substituted THP rings.
Tetrabutyl ammonium fluoride (TBAF) was found to be capable of catalyzing the intramolecular hydroalkoxylation of 6-hydroxyhex-2-ynoates and 7-hydroxyhept-2-ynoates. The reaction could be used to prepare 2,5-substituted THF rings and 2,6-substituted THP rings.
2011, 22(8): 935-938
doi: 10.1016/j.cclet.2011.01.025
Abstract:
A novel series of transition metal complexes have been synthesized from the reaction of 5-((3-(methylthio)-5-(pyridin-4-yl)-4H-1,2,4-triazol-4-ylamino)methyl)quinolin-8-ol with transition metal salts. The structures of these compounds have been elucidated by elemental and spectral analysis. Furthermore, compounds were screened for in vitro antimicrobial activity against the representative panel of two Gram-positive and two Gram-negative bacteria and two strains of fungus. The various compounds show potent inhibitory action against test organisms.
A novel series of transition metal complexes have been synthesized from the reaction of 5-((3-(methylthio)-5-(pyridin-4-yl)-4H-1,2,4-triazol-4-ylamino)methyl)quinolin-8-ol with transition metal salts. The structures of these compounds have been elucidated by elemental and spectral analysis. Furthermore, compounds were screened for in vitro antimicrobial activity against the representative panel of two Gram-positive and two Gram-negative bacteria and two strains of fungus. The various compounds show potent inhibitory action against test organisms.
2011, 22(8): 939-942
doi: 10.1016/j.cclet.2011.01.039
Abstract:
Stable and non-hygroscopic silica gel supported aluminium chloride (SiO2-AlCl3), which is prepared easily from cheap and commercially available compounds was found to be an environmentally friendly heterogeneous catalyst for the condensation of indole with aldehydes and ketones to afford bis-indolylmethanes at room temperature under solvent-free conditions. The catalyst can be reused up to five times after simple washing with ether.
Stable and non-hygroscopic silica gel supported aluminium chloride (SiO2-AlCl3), which is prepared easily from cheap and commercially available compounds was found to be an environmentally friendly heterogeneous catalyst for the condensation of indole with aldehydes and ketones to afford bis-indolylmethanes at room temperature under solvent-free conditions. The catalyst can be reused up to five times after simple washing with ether.
2011, 22(8): 943-946
doi: 10.1016/j.cclet.2011.01.040
Abstract:
The addition of pyridine-2-carboxaldoxime or α-furildioxime to dialkyl acetylenedicarboxylates under neutral conditions in the presence of alkyl isocyanides leads to ketenimines and bis(ketenimines) in good yields.
The addition of pyridine-2-carboxaldoxime or α-furildioxime to dialkyl acetylenedicarboxylates under neutral conditions in the presence of alkyl isocyanides leads to ketenimines and bis(ketenimines) in good yields.
2011, 22(8): 947-950
doi: 10.1016/j.cclet.2011.03.006
Abstract:
A new homologous series of isoflavone-based ethers, 7-(4-bromoalkyloxy)-3-(4'-decyloxyphenyl)-4H-1-benzopyran-4-ones were synthesized and characterized. The mesomorphic properties of all homologues were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Enantiotropic smectic A (SmA) phase was observed for all homologues. The structure-property study was carried out by comparing the mesomorphic behavior of the homologues with those previously reported analogues. The bromine atom from the alkyloxy side chain of the benzene ring fused to the heterocyclic moiety was found to be capable of changing the mesomorphic properties.
A new homologous series of isoflavone-based ethers, 7-(4-bromoalkyloxy)-3-(4'-decyloxyphenyl)-4H-1-benzopyran-4-ones were synthesized and characterized. The mesomorphic properties of all homologues were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Enantiotropic smectic A (SmA) phase was observed for all homologues. The structure-property study was carried out by comparing the mesomorphic behavior of the homologues with those previously reported analogues. The bromine atom from the alkyloxy side chain of the benzene ring fused to the heterocyclic moiety was found to be capable of changing the mesomorphic properties.
2011, 22(8): 951-953
doi: 10.1016/j.cclet.2011.01.034
Abstract:
A new approach to the facile synthesis of 2-substituted-quinazolin-4(3H)-ones and its derivatives using the condensation reaction of substituted 2-aminobenzamide and orthoesters is reported.
A new approach to the facile synthesis of 2-substituted-quinazolin-4(3H)-ones and its derivatives using the condensation reaction of substituted 2-aminobenzamide and orthoesters is reported.
2011, 22(8): 954-956
doi: 10.1016/j.cclet.2011.01.031
Abstract:
A new 3-(3,4-methylenedioxyphenyl)-propane-l,2-diol glycoside, named cinnamomdiol A (1), together with two known compounds, 3-(3,4-methylenedioxyphenyl)-propane-1,2-diol (2) and taxifolin (3), was isolated from the roots of Cinnamomum camphora. Their structures were determined on the basis of spectroscopic evidences. Compounds 2 and 3 were isolated from the title plant for the first time.
A new 3-(3,4-methylenedioxyphenyl)-propane-l,2-diol glycoside, named cinnamomdiol A (1), together with two known compounds, 3-(3,4-methylenedioxyphenyl)-propane-1,2-diol (2) and taxifolin (3), was isolated from the roots of Cinnamomum camphora. Their structures were determined on the basis of spectroscopic evidences. Compounds 2 and 3 were isolated from the title plant for the first time.
2011, 22(8): 957-960
doi: 10.1016/j.cclet.2011.01.027
Abstract:
A new triterpenoid saponin, 3β-O-{β-D-glucopyranosyl-(1→4)-[β-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl}-16α, 28-dihydroxyolean-12-en-30-oic acid 30-O-β-D-glucopyranosyl ester (ardisicrenoside N, 1), together with two known saponins, ardisicrenoside C (2) and D (3), were isolated from the roots of Ardisia crenata Sim. Their structures were elucidated by extensive spectral analysis and chemical evidences. Saponins 1 showed cytotoxicity against MCI-7 and NCI-H460 cancer cell lines at 11.0 μmol/L and 22.1 μmol/L in vitro.
A new triterpenoid saponin, 3β-O-{β-D-glucopyranosyl-(1→4)-[β-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl}-16α, 28-dihydroxyolean-12-en-30-oic acid 30-O-β-D-glucopyranosyl ester (ardisicrenoside N, 1), together with two known saponins, ardisicrenoside C (2) and D (3), were isolated from the roots of Ardisia crenata Sim. Their structures were elucidated by extensive spectral analysis and chemical evidences. Saponins 1 showed cytotoxicity against MCI-7 and NCI-H460 cancer cell lines at 11.0 μmol/L and 22.1 μmol/L in vitro.
2011, 22(8): 961-963
doi: 10.1016/j.cclet.2011.01.029
Abstract:
A new phenylethanoid glycoside, sculponiside (1) was isolated from the aerial parts of Isodon sculponeatus (Vaniot) Kudo, along with six known compounds martynoside (2), verbascoside (3), (+)-hydroxypinoresinol-8-O-β-D-glucoside (4), cedrusin (5), 7-megastigmene-3S,5R,6R,7E,9S-tetrol (6) and 4-oxo-β-ionol-β-D-glucopyranoside (7). Their chemical structures were elucidated from physicochemical data and by acidic hydrolysis.
A new phenylethanoid glycoside, sculponiside (1) was isolated from the aerial parts of Isodon sculponeatus (Vaniot) Kudo, along with six known compounds martynoside (2), verbascoside (3), (+)-hydroxypinoresinol-8-O-β-D-glucoside (4), cedrusin (5), 7-megastigmene-3S,5R,6R,7E,9S-tetrol (6) and 4-oxo-β-ionol-β-D-glucopyranoside (7). Their chemical structures were elucidated from physicochemical data and by acidic hydrolysis.
2011, 22(8): 964-968
doi: 10.1016/j.cclet.2011.01.019
Abstract:
Coral reef-like PANI nanotubes composed of nanopaticles were successfully synthesized by a reactive template of manganese oxide. The structure was characterized by using SEM, TEM, and FT-IR, and the supercapacitive behaviors of these nanotubes were investigated with cyclic voltammetry (CV), and charge-discharge tests, respectively. A maximum specific capacitance of 533 F/g could be achieved in 1 mol/L aqueous H2SO4 with the potential range of -0.2 to 0.8 V (vs. the saturated calomel electrode) in a half-cell setup configuration for PANI electrode, suggesting its potential application in the electrode material for electrochemical capacitors.
Coral reef-like PANI nanotubes composed of nanopaticles were successfully synthesized by a reactive template of manganese oxide. The structure was characterized by using SEM, TEM, and FT-IR, and the supercapacitive behaviors of these nanotubes were investigated with cyclic voltammetry (CV), and charge-discharge tests, respectively. A maximum specific capacitance of 533 F/g could be achieved in 1 mol/L aqueous H2SO4 with the potential range of -0.2 to 0.8 V (vs. the saturated calomel electrode) in a half-cell setup configuration for PANI electrode, suggesting its potential application in the electrode material for electrochemical capacitors.
2011, 22(8): 969-972
doi: 10.1016/j.cclet.2011.03.003
Abstract:
A cobalt(Ⅱ) complex containing mixed-ligands of 1, 10-phenathrolinc (phen) and glycollic acid (GA). [Co(GA)2(phen)] was synthesized and its structure was characterized by X-ray diffraction. The interaction of the complex with DNA was investigated by electronic absorption spectra and electrochemical methods. Electronic absorption spectrum experiments showed that after interaction with DNA, the characteristic absorption peaks of [Co(GA)2(phen)] underwent hypochromic effect as well as red-shift. Also, the binding strength of 3.8×l04 L/mol was estimated by titration method. Electrochemical assays revealed that the redox peak currents of the complex decreased obviously accompanied by a positive shift of the formal potential after association with DNA. All these results revealed that the synthesized cobalt complex bound with DNA via an intercalation mode.
A cobalt(Ⅱ) complex containing mixed-ligands of 1, 10-phenathrolinc (phen) and glycollic acid (GA). [Co(GA)2(phen)] was synthesized and its structure was characterized by X-ray diffraction. The interaction of the complex with DNA was investigated by electronic absorption spectra and electrochemical methods. Electronic absorption spectrum experiments showed that after interaction with DNA, the characteristic absorption peaks of [Co(GA)2(phen)] underwent hypochromic effect as well as red-shift. Also, the binding strength of 3.8×l04 L/mol was estimated by titration method. Electrochemical assays revealed that the redox peak currents of the complex decreased obviously accompanied by a positive shift of the formal potential after association with DNA. All these results revealed that the synthesized cobalt complex bound with DNA via an intercalation mode.
2011, 22(8): 973-976
doi: 10.1016/j.cclet.2011.01.022
Abstract:
The interaction of lysozyme (Lys) and gold nanoparticles was investigated via UV-vis absorption and resonance light-scattering method. There are some changes of the plasmon absorption and resonance light-scattering of gold nanoparticles that were observed via the addition of Lys. The normalized plasmon absorption and resonance light-scattering intensity with gold nanoparticles were both linear with 1-20 nmol/L Lys. A simple model about the component of the gold nanoparticles and Lys complex was established and the calculated result was fitted well in their concentration ratio. Furthermore, the activity analysis of Lys showed that the interaction was weak and nondestructive.
The interaction of lysozyme (Lys) and gold nanoparticles was investigated via UV-vis absorption and resonance light-scattering method. There are some changes of the plasmon absorption and resonance light-scattering of gold nanoparticles that were observed via the addition of Lys. The normalized plasmon absorption and resonance light-scattering intensity with gold nanoparticles were both linear with 1-20 nmol/L Lys. A simple model about the component of the gold nanoparticles and Lys complex was established and the calculated result was fitted well in their concentration ratio. Furthermore, the activity analysis of Lys showed that the interaction was weak and nondestructive.
2011, 22(8): 977-980
doi: 0.1016/j.cclet.2010.12.031
Abstract:
In this work a new Lu3+ PVC-membrane sensor based on 2,2'-dithiobis(4-methyIthiazole) (TMT) has been fabricated. The sensor exhibits a Nernstian slope of 19.6±0.4 mV decade -1 in the concentration range of 1.0×10 -6-1.0×10 -2 mol L -1 and a detection limit of 6.8×10 -7 mol L -1.It could work well in the pH range of 2.7-9.6. The selectivity of the sensor against a lot of common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions was very good.
In this work a new Lu3+ PVC-membrane sensor based on 2,2'-dithiobis(4-methyIthiazole) (TMT) has been fabricated. The sensor exhibits a Nernstian slope of 19.6±0.4 mV decade -1 in the concentration range of 1.0×10 -6-1.0×10 -2 mol L -1 and a detection limit of 6.8×10 -7 mol L -1.It could work well in the pH range of 2.7-9.6. The selectivity of the sensor against a lot of common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions was very good.
2011, 22(8): 981-984
doi: 10.1016/j.cclet.2011.01.024
Abstract:
The fabrication of poly (2,6-pyridinedicarboxylic acid)/MWNTs modified glass electrode (PPDA/MWNTs/GCE) was proposed and used for individual or simultaneous determination of guanine and adenine. The performances of the PPDA/MWNTs/GCE were characterized with cyclic voltammetry (CV). The modified electrode exhibited enhanced electrocatalytic behavior and good stability for the detection of guanine and adenine. Differential pulse voltammetry (DPV) was used to determine the concentration of guanine, adenine. The detection limit (S/N=3) for guanine and adenine was 0.045 μmol/L and 0.05 μmol/L, respectively. The electrochemical method for the measurement of guanine and adenine in calf thymus DNA was also developed with this modified electrode and the result was satisfactory.
The fabrication of poly (2,6-pyridinedicarboxylic acid)/MWNTs modified glass electrode (PPDA/MWNTs/GCE) was proposed and used for individual or simultaneous determination of guanine and adenine. The performances of the PPDA/MWNTs/GCE were characterized with cyclic voltammetry (CV). The modified electrode exhibited enhanced electrocatalytic behavior and good stability for the detection of guanine and adenine. Differential pulse voltammetry (DPV) was used to determine the concentration of guanine, adenine. The detection limit (S/N=3) for guanine and adenine was 0.045 μmol/L and 0.05 μmol/L, respectively. The electrochemical method for the measurement of guanine and adenine in calf thymus DNA was also developed with this modified electrode and the result was satisfactory.
2011, 22(8): 985-988
doi: 10.1016/j.cclet.2011.03.005
Abstract:
Structurally simple salicylaldehyde-based fluorescent sensors for amino acids have been obtained by one-step or two-step synthesis. These sensors show significant fluorescence enhancement in the presence of many amino acids at concentrations as low as 10 -5 mol/L. The reversible reaction of the aldehydes with amino acids to form imines in aqueous solution is proposed to account for the observed fluorescence enhancement.
Structurally simple salicylaldehyde-based fluorescent sensors for amino acids have been obtained by one-step or two-step synthesis. These sensors show significant fluorescence enhancement in the presence of many amino acids at concentrations as low as 10 -5 mol/L. The reversible reaction of the aldehydes with amino acids to form imines in aqueous solution is proposed to account for the observed fluorescence enhancement.
2011, 22(8): 989-992
doi: 10.1016/j.cclet.2011.04.010
Abstract:
Molecular crowding is a new concept to obtain molecularly imprinted polymers (MIPs) with greater capacity and selectivity. In this work, molecular crowding agent was firstly applied to the preparation of MIPs monolithic column. A new polymerization system based on molecular crowding surrounding was developed to prepare enrofloxacin-imprinted monolith, which was composed of polystyrene and tetrahydrofuran. The result showed that the monolithic MIPs under molecular crowding conditions presented good molecular recognition for enrofloxacin with an imprinting factor of 3.03.
Molecular crowding is a new concept to obtain molecularly imprinted polymers (MIPs) with greater capacity and selectivity. In this work, molecular crowding agent was firstly applied to the preparation of MIPs monolithic column. A new polymerization system based on molecular crowding surrounding was developed to prepare enrofloxacin-imprinted monolith, which was composed of polystyrene and tetrahydrofuran. The result showed that the monolithic MIPs under molecular crowding conditions presented good molecular recognition for enrofloxacin with an imprinting factor of 3.03.
2011, 22(8): 993-996
doi: 10.1016/j.cclet.2011.03.001
Abstract:
Lead nanotapes were synthesized in liquid ammonia solvent in the presence of sodium metal at low temperature. The process was template free. Transmission electron microscopy (TEM) observations and X-ray diffraction (XRD) characterizations revealed that the as-prepared Pb nanotapes have average diameters in the range of 40-50 nm, and lengths up to several hundred nanometers, and exhibit cubic crystal structures.
Lead nanotapes were synthesized in liquid ammonia solvent in the presence of sodium metal at low temperature. The process was template free. Transmission electron microscopy (TEM) observations and X-ray diffraction (XRD) characterizations revealed that the as-prepared Pb nanotapes have average diameters in the range of 40-50 nm, and lengths up to several hundred nanometers, and exhibit cubic crystal structures.
2011, 22(8): 997-1000
doi: 10.1016/j.cclet.2011.01.028
Abstract:
A novel waterborne stilbene-based polyurethane fluorescent brightener dispersion WPU-VBL was synthesized by incorporating chemically disodium 4,4'-bis[(4-anilino-6-hydroxyethylamino-1,3,5-triazin-2-y1)amino]stilbene-2,2'-disulphonate (VBL) into the polyurethane chain using isophorone diisocyanate, poly(propylene glycol) and 2,2-dimethylol propionic acid. The structure of WPU-VBL was confirmed by means of Fourier transform infrared spectroscopy. The UV-vis absorption analysis showed a hypsochromic shift of 16 nm when VBL was blocked into polyurethane chain. Number average molecular weight of 2.1×104, molecular weight distribution of 2.1 and average latex particle size of about 70 nm for WPU-VBL were determined based on the analysis of gel permeation chromatography and laser particle size analyzer. It was found that the fluorescence intensity of WPU-VBL was prominently enhanced because of the micro-circumstance of VBL and the fluorescence of WPU-VBL was very stable.
A novel waterborne stilbene-based polyurethane fluorescent brightener dispersion WPU-VBL was synthesized by incorporating chemically disodium 4,4'-bis[(4-anilino-6-hydroxyethylamino-1,3,5-triazin-2-y1)amino]stilbene-2,2'-disulphonate (VBL) into the polyurethane chain using isophorone diisocyanate, poly(propylene glycol) and 2,2-dimethylol propionic acid. The structure of WPU-VBL was confirmed by means of Fourier transform infrared spectroscopy. The UV-vis absorption analysis showed a hypsochromic shift of 16 nm when VBL was blocked into polyurethane chain. Number average molecular weight of 2.1×104, molecular weight distribution of 2.1 and average latex particle size of about 70 nm for WPU-VBL were determined based on the analysis of gel permeation chromatography and laser particle size analyzer. It was found that the fluorescence intensity of WPU-VBL was prominently enhanced because of the micro-circumstance of VBL and the fluorescence of WPU-VBL was very stable.
2011, 22(8): 1001-1004
doi: 10.1016/j.cclet.2010.12.052
Abstract:
Two novel copolymers based on squaraine and fluorine units have been synthesized through palladium catalyzed Suzuki coupling reaction and Sonogashira coupling reaction, respectively. The structures and properties of the two copolymers were characterized by FT-IR, NMR, UV-vis absorbance (Abs), gel permeation chromatography (GPC), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and cyclic voltammetry (CV). The solution absorption spectrums of P1 and P2 show two distinct absorption bands, one locates at 300-500 nm and the other at 600-800 nm. The absorption spectrums of P1 and P2 in films are broadened obviously and the spectral responses are extended up to 900 nm. Thermal gravimetric analysis demonstrates that the polymers are stable. Cyclic voltammetry experiment shows that the band gaps of the copolymers are 1.65 eV and 1.67 eV, respectively, suggesting their potential for applications as solar cells materials.
Two novel copolymers based on squaraine and fluorine units have been synthesized through palladium catalyzed Suzuki coupling reaction and Sonogashira coupling reaction, respectively. The structures and properties of the two copolymers were characterized by FT-IR, NMR, UV-vis absorbance (Abs), gel permeation chromatography (GPC), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and cyclic voltammetry (CV). The solution absorption spectrums of P1 and P2 show two distinct absorption bands, one locates at 300-500 nm and the other at 600-800 nm. The absorption spectrums of P1 and P2 in films are broadened obviously and the spectral responses are extended up to 900 nm. Thermal gravimetric analysis demonstrates that the polymers are stable. Cyclic voltammetry experiment shows that the band gaps of the copolymers are 1.65 eV and 1.67 eV, respectively, suggesting their potential for applications as solar cells materials.
2011, 22(8): 1005-1008
doi: 10.1016/j.cclet.2011.01.032
Abstract:
A novel phosphorescent cyclometalated platinum dimer with bis-[2-(p-dodecyloxyphenyl) pyridyl]-hexane-l,6-diol as ligand and 1,3-( 1-n-hexyl,3-n-heptadecyl) diketone as ancillary ligand was synthesized. The chemical structure and liquid crystal property of the dimer were characterized by 1H NMR, ESI-MS, polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The aligned film of title compound on the rubbed polyimide film is intensely emissive at room temperature with emission maximum at 516 nm. The luminescence dichroic ratio (I∥/I⊥) at 516 nm is 3.1.
A novel phosphorescent cyclometalated platinum dimer with bis-[2-(p-dodecyloxyphenyl) pyridyl]-hexane-l,6-diol as ligand and 1,3-( 1-n-hexyl,3-n-heptadecyl) diketone as ancillary ligand was synthesized. The chemical structure and liquid crystal property of the dimer were characterized by 1H NMR, ESI-MS, polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The aligned film of title compound on the rubbed polyimide film is intensely emissive at room temperature with emission maximum at 516 nm. The luminescence dichroic ratio (I∥/I⊥) at 516 nm is 3.1.
