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2014 Volume 25 Issue 2
2014, 25(2): 193-196
Abstract:
A short formal stereoselective synthesis of (—)-swainsonine (1) is described. Our synthesis started with the versatile building block (R)-3-benzyloxyglutarimide 5. Through controlled regioselective reduction, Ley's-sulfone chemistry (N-α-sulfonylation and ZnCl2-catalyzed N-α-amidovinylation), an RCM reaction, and an amide reduction, the synthesis of unsaturated indolizidine (8R,8aS)-3 has been achieved in five steps. The indolizidine (8R,8aS)-3 is an advanced intermediate toward the synthesis of (—)-swainsonine (1).
A short formal stereoselective synthesis of (—)-swainsonine (1) is described. Our synthesis started with the versatile building block (R)-3-benzyloxyglutarimide 5. Through controlled regioselective reduction, Ley's-sulfone chemistry (N-α-sulfonylation and ZnCl2-catalyzed N-α-amidovinylation), an RCM reaction, and an amide reduction, the synthesis of unsaturated indolizidine (8R,8aS)-3 has been achieved in five steps. The indolizidine (8R,8aS)-3 is an advanced intermediate toward the synthesis of (—)-swainsonine (1).
2014, 25(2): 197-200
Abstract:
Spiro heterocycles frequently occur in bioactive molecules. In the pursuit of neonicotinoids with spiro heterocycles, three types of novel neonicotinoids with spirobenzofuranone, spirooxindole or spiroacenaphythylenone framework were designed and synthesized. Insecticidal evaluation showed that some of spirobenzofuranone containing neonicotinoids exhibited moderate activity against cowpea aphid, armyworm or brown planthopper.
Spiro heterocycles frequently occur in bioactive molecules. In the pursuit of neonicotinoids with spiro heterocycles, three types of novel neonicotinoids with spirobenzofuranone, spirooxindole or spiroacenaphythylenone framework were designed and synthesized. Insecticidal evaluation showed that some of spirobenzofuranone containing neonicotinoids exhibited moderate activity against cowpea aphid, armyworm or brown planthopper.
2014, 25(2): 201-204
Abstract:
A method was developed for the determination of tetraethyl ammonium (TEA) by reversed-phase ionpair chromatography with indirect ultraviolet detection. Chromatographic separation was achieved on a reversed-phase C18 column using background ultraviolet absorbing reagent - ion-pair reagent - organic solvent as mobile phase. The effects of the background ultraviolet absorbing reagents, detection wavelength, ion-pair reagents, organic solvents and column temperature on the determination method were investigated and the retention rules discussed. Results found that TEA could be successfully analyzed by using 0.7 μmol/L 4-aminophenol hydrochloride and 0.15 μmol/L 1-heptanesulfonic acid sodium mixed with 20% (v/v) methanol asmobile phase at a UV detection wavelength of 230 nm. Under these conditions, the retention time of tetraethyl ammonium was 2.85 min. The detection limit (S/N = 3) for TEA was 0.06 mg/L. The relative standard deviations (n = 5) for peak area and retention time were 0.35% and 0.02%, respectively. The method has been successfully applied to the determination of synthesized tetraethyl ammonium bromide. Recovery of tetraethyl ammonium after spiking was 99.1%.
A method was developed for the determination of tetraethyl ammonium (TEA) by reversed-phase ionpair chromatography with indirect ultraviolet detection. Chromatographic separation was achieved on a reversed-phase C18 column using background ultraviolet absorbing reagent - ion-pair reagent - organic solvent as mobile phase. The effects of the background ultraviolet absorbing reagents, detection wavelength, ion-pair reagents, organic solvents and column temperature on the determination method were investigated and the retention rules discussed. Results found that TEA could be successfully analyzed by using 0.7 μmol/L 4-aminophenol hydrochloride and 0.15 μmol/L 1-heptanesulfonic acid sodium mixed with 20% (v/v) methanol asmobile phase at a UV detection wavelength of 230 nm. Under these conditions, the retention time of tetraethyl ammonium was 2.85 min. The detection limit (S/N = 3) for TEA was 0.06 mg/L. The relative standard deviations (n = 5) for peak area and retention time were 0.35% and 0.02%, respectively. The method has been successfully applied to the determination of synthesized tetraethyl ammonium bromide. Recovery of tetraethyl ammonium after spiking was 99.1%.
2014, 25(2): 205-208
Abstract:
This study shows that minor amount of water plays a very important role in solvent-free hydrogenation of halogenated nitrobenzenes. For dried sponge Pd, the reaction cannot occur in the absence of water. For Pd/C catalyst, minor amount of water reduces the induction time, increases the reaction rate and reaction TOFs. Water might enhance the diffusion, adsorption and dissociation of H2 on Pd catalysts.
This study shows that minor amount of water plays a very important role in solvent-free hydrogenation of halogenated nitrobenzenes. For dried sponge Pd, the reaction cannot occur in the absence of water. For Pd/C catalyst, minor amount of water reduces the induction time, increases the reaction rate and reaction TOFs. Water might enhance the diffusion, adsorption and dissociation of H2 on Pd catalysts.
2014, 25(2): 209-211
Abstract:
1-Amino-3-dodecyl-1,2,3-triazolium nitrate, as a novel energetic surfactant, has been synthesized in four steps, namely addition-elimination, cyclization, alkylation and metathesis. Its structure was confirmed by 1H NMR, IR, and MS. The effects of various reaction parameters, including stoichiometry, reaction temperature and time, were investigated in details. In addition, the physical and chemical properties of this energetic surfactant were measured.
1-Amino-3-dodecyl-1,2,3-triazolium nitrate, as a novel energetic surfactant, has been synthesized in four steps, namely addition-elimination, cyclization, alkylation and metathesis. Its structure was confirmed by 1H NMR, IR, and MS. The effects of various reaction parameters, including stoichiometry, reaction temperature and time, were investigated in details. In addition, the physical and chemical properties of this energetic surfactant were measured.
2014, 25(2): 212-214
Abstract:
Diammonium hydrogen phosphate and potassium carbonate-catalyzed one-pot synthesis of 1,4-phenylene-bis(2-amino-4H-pyran-3-carbonitrile and 2-amino-4-aryl-4H-pyran-3-carbonitrile derivatives has been achieved by a three-component cyclocondensation of aldehydes, malononitrile, and different nucleophiles in aqueous medium in high yields.
Diammonium hydrogen phosphate and potassium carbonate-catalyzed one-pot synthesis of 1,4-phenylene-bis(2-amino-4H-pyran-3-carbonitrile and 2-amino-4-aryl-4H-pyran-3-carbonitrile derivatives has been achieved by a three-component cyclocondensation of aldehydes, malononitrile, and different nucleophiles in aqueous medium in high yields.
2014, 25(2): 215-217
Abstract:
A new methodology for the synthesis of a green plasticizer acetyltributylcitrate through a transesterification reaction was developed. Under the catalysis of alkyl-substituted imidazol-type N-heterocyclic carbenes, tributyl citrate can react with vinyl acetate smoothly to give ATBC in high yield.
A new methodology for the synthesis of a green plasticizer acetyltributylcitrate through a transesterification reaction was developed. Under the catalysis of alkyl-substituted imidazol-type N-heterocyclic carbenes, tributyl citrate can react with vinyl acetate smoothly to give ATBC in high yield.
2014, 25(2): 218-220
Abstract:
A simple, green, and efficient method for the N-tert-butoxycarbonylation of amines by pyridinium 2,2,2- trifluoroacetate ([Py][OTf]) as an efficient and reusable catalyst is reported. In general, electron donating groups on aryl group give rise to the higher yields than electron withdrawing groups. Clean reaction, short reaction times, high yields, reusability of catalyst, and easy preparation of it are some advantages of this work.
A simple, green, and efficient method for the N-tert-butoxycarbonylation of amines by pyridinium 2,2,2- trifluoroacetate ([Py][OTf]) as an efficient and reusable catalyst is reported. In general, electron donating groups on aryl group give rise to the higher yields than electron withdrawing groups. Clean reaction, short reaction times, high yields, reusability of catalyst, and easy preparation of it are some advantages of this work.
2014, 25(2): 221-225
Abstract:
A series of novel chelating fibers containing sulfur, nitrogen, oxygen heteroatoms were prepared via the functionalization of chloromethylated polyphenylene sulfide (CMPPS). The structures, micromorphology and physicochemical properties of these fibrous adsorptive materials were characterized by FT-IR, elementary analysis, TG and SEM-EDS. The results show that chelating fibers had high functional group contents (3.94 mmol/g for thiourea, 3.85 mmol/g for mercapto, 5.00 mmol/g for methylamine and 6.07 mmol/g for ethylenediamine, respectively). Owing to the unique matrix of polyphenylene sulfide fiber, these fibrous adsorbents possess excellent thermostability. This syntheticmethod proved a simple and efficient way for the preparation of chelating fibers.
A series of novel chelating fibers containing sulfur, nitrogen, oxygen heteroatoms were prepared via the functionalization of chloromethylated polyphenylene sulfide (CMPPS). The structures, micromorphology and physicochemical properties of these fibrous adsorptive materials were characterized by FT-IR, elementary analysis, TG and SEM-EDS. The results show that chelating fibers had high functional group contents (3.94 mmol/g for thiourea, 3.85 mmol/g for mercapto, 5.00 mmol/g for methylamine and 6.07 mmol/g for ethylenediamine, respectively). Owing to the unique matrix of polyphenylene sulfide fiber, these fibrous adsorbents possess excellent thermostability. This syntheticmethod proved a simple and efficient way for the preparation of chelating fibers.
2014, 25(2): 226-228
Abstract:
A novel series of calix[4]arene derivatives were synthesized via a Pd-catalyzed Sonogashira coupling reaction from para-substituted iodobenzene and 25,27-dipropargyl-calix[4]arene. Fluorescence studies found that nitro-phenols clearly exhibited quenching effects on 2c. Moreover, we minimized the free energy of the complexes by theoretical calculations. As the result, the π-π stacking interactions take place between the 4-nitrophenol and calix[4]arene, which may lead to the significant fluorescence quench.
A novel series of calix[4]arene derivatives were synthesized via a Pd-catalyzed Sonogashira coupling reaction from para-substituted iodobenzene and 25,27-dipropargyl-calix[4]arene. Fluorescence studies found that nitro-phenols clearly exhibited quenching effects on 2c. Moreover, we minimized the free energy of the complexes by theoretical calculations. As the result, the π-π stacking interactions take place between the 4-nitrophenol and calix[4]arene, which may lead to the significant fluorescence quench.
2014, 25(2): 229-233
Abstract:
The incidence of invasive fungal infections is increasing rapidly. Clinically available antifungal agents suffer from limited efficacy and severe resistance. There is an urgent need to discover antifungal lead compounds with novel chemical scaffold. On the basis of our previously identified tetrahydrocarbazole antifungal leads, the structure-activity relationship was further explored by modifying the scaffold and the side chains. Several targeted compounds showed potent activity against Candida species. Particularly, compound 13i showed better antifungal activity than the lead compound, which can be used as a good starting point for further optimization.
The incidence of invasive fungal infections is increasing rapidly. Clinically available antifungal agents suffer from limited efficacy and severe resistance. There is an urgent need to discover antifungal lead compounds with novel chemical scaffold. On the basis of our previously identified tetrahydrocarbazole antifungal leads, the structure-activity relationship was further explored by modifying the scaffold and the side chains. Several targeted compounds showed potent activity against Candida species. Particularly, compound 13i showed better antifungal activity than the lead compound, which can be used as a good starting point for further optimization.
2014, 25(2): 234-236
Abstract:
A simple and efficient synthetic protocol has been developed using a one-pot multicomponent reaction (MCR) involving 2-aminophenols, dialkyl acetylenedicarboxylates, and ethyl bromopyruvate in poly(ethyleneglycol). This protocol was utilized to prepare novel pyrrolo[2,1-c][1,4]benzoxazines in excellent yields.
A simple and efficient synthetic protocol has been developed using a one-pot multicomponent reaction (MCR) involving 2-aminophenols, dialkyl acetylenedicarboxylates, and ethyl bromopyruvate in poly(ethyleneglycol). This protocol was utilized to prepare novel pyrrolo[2,1-c][1,4]benzoxazines in excellent yields.
2014, 25(2): 237-242
Abstract:
A series of pyrene derivatives with different asymmetrical substituents were successfully synthesized and characterized. The geometrical electronic structures of the asymmetrical pyrene derivatives were performed by density functional theory (DFT) calculations. The results of photophysical spectra and electrochemical analysis indicated that the optical or electric properties of the pyrene derivatives could be tuned by adjust the π-conjugation lengths of the substituents. Furthermore, through a phase exchange self-assembly method, the highly organized morphologies were observed by SEM.
A series of pyrene derivatives with different asymmetrical substituents were successfully synthesized and characterized. The geometrical electronic structures of the asymmetrical pyrene derivatives were performed by density functional theory (DFT) calculations. The results of photophysical spectra and electrochemical analysis indicated that the optical or electric properties of the pyrene derivatives could be tuned by adjust the π-conjugation lengths of the substituents. Furthermore, through a phase exchange self-assembly method, the highly organized morphologies were observed by SEM.
2014, 25(2): 243-246
Abstract:
A new 2D coordination polymer, [Cd(tpim)(1,5-nds)]n(1), was constructed from 1,5-naphthalenedisulfonate (1,5-nds), 2,4,5-tri(4-pyridyl)-imidazole (tpim) and Cd(CH3COO)2·2H2O, which can be subsequently used to promote the epoxide ring-opening reaction of epoxides and amines with remarkable catalytic activity. In addition, the thermal and luminescent properties of 1 in the solid state were also investigated.
A new 2D coordination polymer, [Cd(tpim)(1,5-nds)]n(1), was constructed from 1,5-naphthalenedisulfonate (1,5-nds), 2,4,5-tri(4-pyridyl)-imidazole (tpim) and Cd(CH3COO)2·2H2O, which can be subsequently used to promote the epoxide ring-opening reaction of epoxides and amines with remarkable catalytic activity. In addition, the thermal and luminescent properties of 1 in the solid state were also investigated.
2014, 25(2): 247-252
Abstract:
Long-wavelength-sensitized luminescent materials are desired for bio-detection. In this paper, we prepared a new kind of luminescent europium nanoparticles by a co-precipitation-condensation method. The luminescent europiumcomplex Eu(tta)3·bpt (tta = thenoyltrifluoroacetonate; bpt = 2-(N,N-di- ethylanilin-4-yl)-4,6-bis(pyrazol-1-yl)-1,3,5-triazine) was used as the active material, being encapsulated in the nanoparticles formed from 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane (PFOTS) and poly(styrene-co-methyl methacrylate) [P(ST-co-MMA)]. The prepared nanoparticles not only can be well dispersed in water but also were of high photostability. Importantly, the nanoparticles displayed maximal excitation wavelength at 425 nm as well as an extended excitation wavelength up to 480 nm and a quantum yield for Eu3+ luminescence of 0.22 (λex = 425 nm, room temperature).
Long-wavelength-sensitized luminescent materials are desired for bio-detection. In this paper, we prepared a new kind of luminescent europium nanoparticles by a co-precipitation-condensation method. The luminescent europiumcomplex Eu(tta)3·bpt (tta = thenoyltrifluoroacetonate; bpt = 2-(N,N-di- ethylanilin-4-yl)-4,6-bis(pyrazol-1-yl)-1,3,5-triazine) was used as the active material, being encapsulated in the nanoparticles formed from 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane (PFOTS) and poly(styrene-co-methyl methacrylate) [P(ST-co-MMA)]. The prepared nanoparticles not only can be well dispersed in water but also were of high photostability. Importantly, the nanoparticles displayed maximal excitation wavelength at 425 nm as well as an extended excitation wavelength up to 480 nm and a quantum yield for Eu3+ luminescence of 0.22 (λex = 425 nm, room temperature).
2014, 25(2): 253-256
Abstract:
Helical 1,2-ethylene-silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like mesopores inside were prepared according to literature procedures. After carbonization, helical carbon/silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like micropores inside were obtained. The morphologies and pore architectures of the carbon/silica nanofibers were characterized using transmission electron microscopy, field-emission scanning electron microscopy, powder X-ray diffraction and N2 sorptions. Although the mesopores inside shrank into micropores, the helical nanostructure remained. Moreover, several carbon/silica nanofibers with lamellar mesopores on the surfaces and concentric circular micropores inside were also obtained. After being calcined in air, helical silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like micropores inside were produced as well.
Helical 1,2-ethylene-silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like mesopores inside were prepared according to literature procedures. After carbonization, helical carbon/silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like micropores inside were obtained. The morphologies and pore architectures of the carbon/silica nanofibers were characterized using transmission electron microscopy, field-emission scanning electron microscopy, powder X-ray diffraction and N2 sorptions. Although the mesopores inside shrank into micropores, the helical nanostructure remained. Moreover, several carbon/silica nanofibers with lamellar mesopores on the surfaces and concentric circular micropores inside were also obtained. After being calcined in air, helical silica nanofibers with lamellar mesopores on the surfaces and twisted rod-like micropores inside were produced as well.
2014, 25(2): 257-260
Abstract:
In this work, we describe the one-pot synthesis of PEGylated mesoporous silica nanoparticles (MSNs) with uniform shape, tunable sizes, and narrow size distributions. The size of these nanoparticles can be controlled from 49 nmto 98 nmby simply varying the concentration of triethanolamine during the basecatalyzed sol-gel reaction. Particles were characterized by transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectrometry, thermogravimetric analysis, and nitrogen adsorption-desorption measurements. These PEGylated MSNs exhibited excellent long-term stability in biological media, which ensures their potential applications in drug delivery.
In this work, we describe the one-pot synthesis of PEGylated mesoporous silica nanoparticles (MSNs) with uniform shape, tunable sizes, and narrow size distributions. The size of these nanoparticles can be controlled from 49 nmto 98 nmby simply varying the concentration of triethanolamine during the basecatalyzed sol-gel reaction. Particles were characterized by transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectrometry, thermogravimetric analysis, and nitrogen adsorption-desorption measurements. These PEGylated MSNs exhibited excellent long-term stability in biological media, which ensures their potential applications in drug delivery.
2014, 25(2): 261-264
Abstract:
A simple and selective method for the determination of silver ions was developed by utilizing the redshift in emission wavelength of the core-shell CdSe/CdS quantum dots (QDs) functionalized with rhodanine upon the addition of Ag+. A linear relationship was observed between the shift and the increase in concentration of Ag+ in the range of 0.0125-12.5 μmol/L. Themechanism of the red-shift was investigated and suggested that the coordination between Ag+ and rhodanine on the QDs surface caused an increase of particle size, which resulted in the red-shift of the QDs' emission wavelength. A detection limit of 2 nmol/L was achieved. The developed method showed superior selectivity and was successfully applied to the determination of silver in environmental samples.
A simple and selective method for the determination of silver ions was developed by utilizing the redshift in emission wavelength of the core-shell CdSe/CdS quantum dots (QDs) functionalized with rhodanine upon the addition of Ag+. A linear relationship was observed between the shift and the increase in concentration of Ag+ in the range of 0.0125-12.5 μmol/L. Themechanism of the red-shift was investigated and suggested that the coordination between Ag+ and rhodanine on the QDs surface caused an increase of particle size, which resulted in the red-shift of the QDs' emission wavelength. A detection limit of 2 nmol/L was achieved. The developed method showed superior selectivity and was successfully applied to the determination of silver in environmental samples.
2014, 25(2): 265-268
Abstract:
A new chelating resin DVB-MA-HDA modified with hydroxamic acid groups was prepared for the fast removal of Ni2+ from water. SEM, BET, elemental analysis, FT-IR spectroscopy and XPS were used to characterize this new adsorbent. Batch adsorption experiment indicated that the equilibrium adsorption capacity of DVB-MA-HD for Ni2+ was more than 130 mg/g, and the adsorption isotherm can be well fitted by the Langmuir model. The adsorption kinetic curve indicates that more than 60% of the adsorption amount of Ni2+ at equilibrium occurred within the initial 20 min. 0.1 mol/L EDTA solution could desorb Ni2+ from DVB-MA-HDA effectively.
A new chelating resin DVB-MA-HDA modified with hydroxamic acid groups was prepared for the fast removal of Ni2+ from water. SEM, BET, elemental analysis, FT-IR spectroscopy and XPS were used to characterize this new adsorbent. Batch adsorption experiment indicated that the equilibrium adsorption capacity of DVB-MA-HD for Ni2+ was more than 130 mg/g, and the adsorption isotherm can be well fitted by the Langmuir model. The adsorption kinetic curve indicates that more than 60% of the adsorption amount of Ni2+ at equilibrium occurred within the initial 20 min. 0.1 mol/L EDTA solution could desorb Ni2+ from DVB-MA-HDA effectively.
2014, 25(2): 269-272
Abstract:
Sub-micron-scaled sodium cobalt oxide (NaCo2O4) powders are prepared by a solid-state reaction method. Characterization using X-ray diffraction indicates that the synthesized NaCo2O4 has a hexagonal layered structure. The electrochemical performance of the NaCo2O4 electrodes is investigated using cyclic voltammetry and galvanostatic charge/discharge in NaOH solution. The results show that the specific capacitance of the NaCo2O4 electrode reaches 337 F/g over the potential range of 0.15-0.65 V at a mass normalized current of 50 mA/g. Moreover, NaCo2O4 exhibits very good stability and cycling performance as a supercapacitor material.
Sub-micron-scaled sodium cobalt oxide (NaCo2O4) powders are prepared by a solid-state reaction method. Characterization using X-ray diffraction indicates that the synthesized NaCo2O4 has a hexagonal layered structure. The electrochemical performance of the NaCo2O4 electrodes is investigated using cyclic voltammetry and galvanostatic charge/discharge in NaOH solution. The results show that the specific capacitance of the NaCo2O4 electrode reaches 337 F/g over the potential range of 0.15-0.65 V at a mass normalized current of 50 mA/g. Moreover, NaCo2O4 exhibits very good stability and cycling performance as a supercapacitor material.
2014, 25(2): 273-278
Abstract:
A simple and effective method for surface molecularly imprinted composite membranes (MICMs) for artemisinin (Ars) based on regenerated cellulose membranes was first prepared through surfaceinitiated atom transfer radical polymerization (ATRP), and the as-prepared MICMs were then evaluated as adsorbents for selective recognition and separation of Ars molecules. Batch rebinding studies were conducted to determine the specific adsorption equilibrium, kinetics and selective permeation performance. The adsorption capacity of MICMs toward Ars by the Langmuir isotherm model was 2.008 mg g-1, which was nearly 5.0 times higher than non-molecularly imprinted composite membranes (NICMs). The kinetic property of MICMs was well-fitted by the pseudo-second-order rate equation. The selective permeation experiments were successfully investigated to prove the excellent selective permeation performance for Ars than the competitive analog (artemether).
A simple and effective method for surface molecularly imprinted composite membranes (MICMs) for artemisinin (Ars) based on regenerated cellulose membranes was first prepared through surfaceinitiated atom transfer radical polymerization (ATRP), and the as-prepared MICMs were then evaluated as adsorbents for selective recognition and separation of Ars molecules. Batch rebinding studies were conducted to determine the specific adsorption equilibrium, kinetics and selective permeation performance. The adsorption capacity of MICMs toward Ars by the Langmuir isotherm model was 2.008 mg g-1, which was nearly 5.0 times higher than non-molecularly imprinted composite membranes (NICMs). The kinetic property of MICMs was well-fitted by the pseudo-second-order rate equation. The selective permeation experiments were successfully investigated to prove the excellent selective permeation performance for Ars than the competitive analog (artemether).
2014, 25(2): 279-282
Abstract:
A new Gd coordination polymer based on 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylate (H3PIDC) has been synthesized under hydrothermal conditions, formulated as {[Gd3(HPIDC)3(PIDC)(H2O)4]·3H2O}n (1). The compound crystallizes in the monoclinic system, space group C2/c with a = 20.951(7), b = 9.515(3), c = 27.483(10)Å, β = 106.176(6)°, Z = 4, V = 5262(3)Å3, C40H45Gd3N12O30, Dc = 2.071 g/cm3, Mr = 1645.63, λ (MoKa) = 0.71073Å, μ = 3.846 mm-1, F(000) = 3204, the final R = 0.0390 and wR = 0.1332. Complex 1 is a two-dimensional MOF built up from T-shaped 3-connected HPIDC2-, PIDC3- and 4-connected metal nodes. Dielectric constant of complex 1 was measured at different frequencies with temperature variation.
A new Gd coordination polymer based on 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylate (H3PIDC) has been synthesized under hydrothermal conditions, formulated as {[Gd3(HPIDC)3(PIDC)(H2O)4]·3H2O}n (1). The compound crystallizes in the monoclinic system, space group C2/c with a = 20.951(7), b = 9.515(3), c = 27.483(10)Å, β = 106.176(6)°, Z = 4, V = 5262(3)Å3, C40H45Gd3N12O30, Dc = 2.071 g/cm3, Mr = 1645.63, λ (MoKa) = 0.71073Å, μ = 3.846 mm-1, F(000) = 3204, the final R = 0.0390 and wR = 0.1332. Complex 1 is a two-dimensional MOF built up from T-shaped 3-connected HPIDC2-, PIDC3- and 4-connected metal nodes. Dielectric constant of complex 1 was measured at different frequencies with temperature variation.
2014, 25(2): 283-286
Abstract:
N-doped TiO2 (N-TiO2) nanoparticles were synthesized via a one-step low temperature (180 ℃) solvothermal route, which adopted NH4NO3 as the nitrogen source. The structure, composition, BET specific surface area, and optical properties of the as-synthesized product were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption- desorption isotherms, and UV-vis diffuse reflectance spectroscopy. In addition, its photocatalytic properties were tested by the reduction of aqueous Cr(VI) under UV and visible light (x > 420 nm) irradiation. It was observed that for the reduction of aqueous Cr(VI), the as-synthesized N-TiO2 nanoparticles not only exhibited much higher photocatalytic activity than P25 TiO2 under UV light, but also exhibited remarkably high photocatalytic activity under visible light (λ > 420 nm).
N-doped TiO2 (N-TiO2) nanoparticles were synthesized via a one-step low temperature (180 ℃) solvothermal route, which adopted NH4NO3 as the nitrogen source. The structure, composition, BET specific surface area, and optical properties of the as-synthesized product were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption- desorption isotherms, and UV-vis diffuse reflectance spectroscopy. In addition, its photocatalytic properties were tested by the reduction of aqueous Cr(VI) under UV and visible light (x > 420 nm) irradiation. It was observed that for the reduction of aqueous Cr(VI), the as-synthesized N-TiO2 nanoparticles not only exhibited much higher photocatalytic activity than P25 TiO2 under UV light, but also exhibited remarkably high photocatalytic activity under visible light (λ > 420 nm).
Magnetically recoverable Cu2O/Fe3O4 composite photocatalysts：Fabrication and photocatalytic activity
2014, 25(2): 287-291
Abstract:
A magnetically separable Cu2O/Fe3O4 magnetic composite photocatalyst was synthesized in large quantities by a fast and simple route. The as-prepared photocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Furthermore, the Cu2O/Fe3O4 composite photocatalysts were tested using methyl orange (MO) degradation reaction under visible light irradiation (100 mW/cm2) and demonstrated to have a high photocatalytic efficiency toward the decomposition of MO under visible light irradiation with good recyclability.
A magnetically separable Cu2O/Fe3O4 magnetic composite photocatalyst was synthesized in large quantities by a fast and simple route. The as-prepared photocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Furthermore, the Cu2O/Fe3O4 composite photocatalysts were tested using methyl orange (MO) degradation reaction under visible light irradiation (100 mW/cm2) and demonstrated to have a high photocatalytic efficiency toward the decomposition of MO under visible light irradiation with good recyclability.
2014, 25(2): 292-294
Abstract:
Azide-functionalization of single-walled carbon nanotubes (SWCNTs) was achieved by electrochemical oxidation of N3- in situ. The functionalized nanotubes were characterized in details by single internal reflection infrared spectroscopy (ATR-FTIR) and thermogravimetic analysis (TGA/MS). The results revealed that a covalent C-N bond had formed and this might provide an effective method for the preparation of azide-functionalized materials, especially carbon materials. The degree of functionalization was measured by X-ray photoelectron spectroscopy (XPS).
Azide-functionalization of single-walled carbon nanotubes (SWCNTs) was achieved by electrochemical oxidation of N3- in situ. The functionalized nanotubes were characterized in details by single internal reflection infrared spectroscopy (ATR-FTIR) and thermogravimetic analysis (TGA/MS). The results revealed that a covalent C-N bond had formed and this might provide an effective method for the preparation of azide-functionalized materials, especially carbon materials. The degree of functionalization was measured by X-ray photoelectron spectroscopy (XPS).
2014, 25(2): 295-298
Abstract:
Althoughmuch effort has been focused on the preparation of stable amorphous calciumphosphate (ACP) nanoparticles in aqueous solution, the redispersibility and long-term stability of ACP nanoparticles in aqueous solution remains an unresolved problem. In this work, stable colloidal ACPs were prepared by using an organic bisphosphonate (BP) as a sterically hindered agent in aqueous solution. The harvested calcium phosphate nanoparticles were characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), Fourier transform infrared (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). ICP-AES, FTIR and XRD results suggested the particles were ACP. DLS and TEM results indicated that the size of the ACP nanoparticles were in the range of 60 nm with a spherical morphology. The resulting calciumphosphate nanoparticles retained its amorphous nature in aqueous solution for at least 6 months at room temperature due to the stabilizing effect of the organic bisphosphonate. Moreover, the surface of the ACP nanoparticles adsorbed with the organic bisphosphate used showed good redispersibility and high colloid stability both in organic and aqueous solutions.
Althoughmuch effort has been focused on the preparation of stable amorphous calciumphosphate (ACP) nanoparticles in aqueous solution, the redispersibility and long-term stability of ACP nanoparticles in aqueous solution remains an unresolved problem. In this work, stable colloidal ACPs were prepared by using an organic bisphosphonate (BP) as a sterically hindered agent in aqueous solution. The harvested calcium phosphate nanoparticles were characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), Fourier transform infrared (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). ICP-AES, FTIR and XRD results suggested the particles were ACP. DLS and TEM results indicated that the size of the ACP nanoparticles were in the range of 60 nm with a spherical morphology. The resulting calciumphosphate nanoparticles retained its amorphous nature in aqueous solution for at least 6 months at room temperature due to the stabilizing effect of the organic bisphosphonate. Moreover, the surface of the ACP nanoparticles adsorbed with the organic bisphosphate used showed good redispersibility and high colloid stability both in organic and aqueous solutions.
2014, 25(2): 299-304
Abstract:
Cholesteryl ester transfer protein (CETP) is a plasma glycoprotein that plays an important role in decreasing high-density lipoprotein cholesterol (HDL-C) levels and increasing low-density lipoprotein cholesterol (LDL-C) levels. Inhibition of CETP may be a new therapy for treating atherosclerosis. Herein, we report the development of a ligand-based pharmacophore model and pharmacophore-based virtual screening of the ZINC/big-n-greasy database, leading to the identification of compound H-10 as a potential CETP inhibitor in vitro. Based on H-10, a series of 3-((3,4-dichlorophenyl)(4-substituted benzyl)amino) propanamides were designed, synthesized, and evaluated against CETP. Compound 4l was found to have the best activity, resulting in 85.0% inhibition of CETP at 10 μmol/L.
Cholesteryl ester transfer protein (CETP) is a plasma glycoprotein that plays an important role in decreasing high-density lipoprotein cholesterol (HDL-C) levels and increasing low-density lipoprotein cholesterol (LDL-C) levels. Inhibition of CETP may be a new therapy for treating atherosclerosis. Herein, we report the development of a ligand-based pharmacophore model and pharmacophore-based virtual screening of the ZINC/big-n-greasy database, leading to the identification of compound H-10 as a potential CETP inhibitor in vitro. Based on H-10, a series of 3-((3,4-dichlorophenyl)(4-substituted benzyl)amino) propanamides were designed, synthesized, and evaluated against CETP. Compound 4l was found to have the best activity, resulting in 85.0% inhibition of CETP at 10 μmol/L.
2014, 25(2): 305-307
Abstract:
A series of benzimidazole bearing 2-pyridones 5a-k were synthesized and assessed in vitro for their activity as antimicrobial agents using the conventional broth dilution method. The results of the antimicrobial study revealed that compounds 5b, 5c, 5j and 5k exhibited substantial antibacterial activity while compound 5d emerged as amore potent antifungal agent compared to the standard drugs chloramphenicol and ketoconazole, respectively. It was observed that the presence of inductively electron withdrawing groups remarkably enhance the antibacterial activity of the newly synthesized compounds. Cytotoxicity studies suggested that none of the tested compounds exhibited any significant cytotoxic effects.
A series of benzimidazole bearing 2-pyridones 5a-k were synthesized and assessed in vitro for their activity as antimicrobial agents using the conventional broth dilution method. The results of the antimicrobial study revealed that compounds 5b, 5c, 5j and 5k exhibited substantial antibacterial activity while compound 5d emerged as amore potent antifungal agent compared to the standard drugs chloramphenicol and ketoconazole, respectively. It was observed that the presence of inductively electron withdrawing groups remarkably enhance the antibacterial activity of the newly synthesized compounds. Cytotoxicity studies suggested that none of the tested compounds exhibited any significant cytotoxic effects.
2014, 25(2): 308-312
Abstract:
An efficient, convenient and environmentally benign one-pot multicomponent reaction for the preparation of pyrimido[4,5-b]quinoline derivatives as biologically, pharmacologically and antibacterially active products has been developed using RuCl3·xH2O as a reusable homogenous catalyst. Use of water as a green solvent, purification of products by non-chromatographic methods, reusability of transition metal homogenous catalyst, saving energy by employing multicomponent reactions, short reaction times and high yields, are some of the advantages of this process.
An efficient, convenient and environmentally benign one-pot multicomponent reaction for the preparation of pyrimido[4,5-b]quinoline derivatives as biologically, pharmacologically and antibacterially active products has been developed using RuCl3·xH2O as a reusable homogenous catalyst. Use of water as a green solvent, purification of products by non-chromatographic methods, reusability of transition metal homogenous catalyst, saving energy by employing multicomponent reactions, short reaction times and high yields, are some of the advantages of this process.
2014, 25(2): 313-316
Abstract:
An efficient synthesis of Biginelli-type compounds using potassium phthalimide as a green, mild, and commercially available organocatalyst in a one-pot, multi-component cyclocondensation reaction of cyclopentanone, aldehydes, and urea/thiourea is reported. The present methodology is a green approach to access 4-aryl-7-(arylmethylene)-3,4,6,7-tetrahydro-1H-cyclopenta[d]pyrimidin-2(5H)-ones/thiones. It offers several merits such as simple operational procedures, no use of hazardous organic solvents, and cheap and environmentally friendly solid basic catalyst.
An efficient synthesis of Biginelli-type compounds using potassium phthalimide as a green, mild, and commercially available organocatalyst in a one-pot, multi-component cyclocondensation reaction of cyclopentanone, aldehydes, and urea/thiourea is reported. The present methodology is a green approach to access 4-aryl-7-(arylmethylene)-3,4,6,7-tetrahydro-1H-cyclopenta[d]pyrimidin-2(5H)-ones/thiones. It offers several merits such as simple operational procedures, no use of hazardous organic solvents, and cheap and environmentally friendly solid basic catalyst.
2014, 25(2): 317-320
Abstract:
Imidazol-1-yl-acetic acid is introduced as a new, efficient and recyclable green bifunctional organocatalyst for the synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions. This catalyst is water soluble and can be separated from the products by simple filtration. The filtrate can be evaporated to dryness and recrystallized from cool methanol to give the recovered catalyst. This organocatalyst was used for the synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions and recycled up to 8 consecutive runs without any losing of its efficiency.
Imidazol-1-yl-acetic acid is introduced as a new, efficient and recyclable green bifunctional organocatalyst for the synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions. This catalyst is water soluble and can be separated from the products by simple filtration. The filtrate can be evaporated to dryness and recrystallized from cool methanol to give the recovered catalyst. This organocatalyst was used for the synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions and recycled up to 8 consecutive runs without any losing of its efficiency.
2014, 25(2): 321-323
Abstract:
Ceric ammonium nitrate (CAN) supported HY-zeolite has been used as an efficient catalyst for the onepot synthesis of 1,8-dioxo-octahydroxanthenes from the readily available 1,3-diketone and aromatic aldehydes under solvent-free conditions. The present methodology is cost-effective in addition to other advantages like high yields of products in shorter reaction time and simple workup procedure without the use of any injurious solvents.
Ceric ammonium nitrate (CAN) supported HY-zeolite has been used as an efficient catalyst for the onepot synthesis of 1,8-dioxo-octahydroxanthenes from the readily available 1,3-diketone and aromatic aldehydes under solvent-free conditions. The present methodology is cost-effective in addition to other advantages like high yields of products in shorter reaction time and simple workup procedure without the use of any injurious solvents.
2014, 25(2): 324-326
Abstract:
Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties (catalytic activity). Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of ecofriendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO2 nanoparticles (TiO2 NPs) were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4(1H)-one synthesis. Synthesized compounds were confirmed using FT-IR, 1H NMR, 13C NMR and GC-MS analyses.
Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties (catalytic activity). Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of ecofriendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO2 nanoparticles (TiO2 NPs) were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4(1H)-one synthesis. Synthesized compounds were confirmed using FT-IR, 1H NMR, 13C NMR and GC-MS analyses.
2014, 25(2): 327-332
Abstract:
A general, mild and efficient protocol for the synthesis of ethyl 4-methyl-2-(thiophen)-2,5-dihydro-1,5- benzodiazepine-3-carboxylate is achieved for first time using H3PMo12O40 in ethanol at 0 ℃ by a onepot, three-component condensation of various thiophene aldehydes, substituted o-phenylenediamines and ethyl acetoacetate. Compared with the conventional synthesis method, this procedure has the advantages of convenient operation, excellent yields, and environmentally benign. A plausible formation mechanism has been proposed. The structure of the products is characterized by 1H NMR, IR, MS and elemental analysis.
A general, mild and efficient protocol for the synthesis of ethyl 4-methyl-2-(thiophen)-2,5-dihydro-1,5- benzodiazepine-3-carboxylate is achieved for first time using H3PMo12O40 in ethanol at 0 ℃ by a onepot, three-component condensation of various thiophene aldehydes, substituted o-phenylenediamines and ethyl acetoacetate. Compared with the conventional synthesis method, this procedure has the advantages of convenient operation, excellent yields, and environmentally benign. A plausible formation mechanism has been proposed. The structure of the products is characterized by 1H NMR, IR, MS and elemental analysis.
2014, 25(2): 333-336
Abstract:
A series of novel 5-phenyl-3-(2,2':5',2''-terthien-5-yl)-4,5-dihydro-1H-pyrazolines were synthesized in this report. Their photoactivated cytotoxicities on the Spodoptera litura (SL) cell line were evaluated using the MTT method. It was noticed that the inhibitory activities of all the conjugates was enhanced when irradiated with UV-A light. Compounds 4, 6 and 8 were found to be most effective with inhibition rates of 88.1%, 88.0%, and 90.5%, respectively. For compound 5, the inhibition rate value was only slightly enhanced under the irradiation treatment (78.3%) compared to the dark treatment (74.8%). The relationship analysis between structure and activity showed that the middle thiophene ring played an important role on the inhibitory activities. It was shown that these compounds could be the potential candidates for new photoactivated pesticides.
A series of novel 5-phenyl-3-(2,2':5',2''-terthien-5-yl)-4,5-dihydro-1H-pyrazolines were synthesized in this report. Their photoactivated cytotoxicities on the Spodoptera litura (SL) cell line were evaluated using the MTT method. It was noticed that the inhibitory activities of all the conjugates was enhanced when irradiated with UV-A light. Compounds 4, 6 and 8 were found to be most effective with inhibition rates of 88.1%, 88.0%, and 90.5%, respectively. For compound 5, the inhibition rate value was only slightly enhanced under the irradiation treatment (78.3%) compared to the dark treatment (74.8%). The relationship analysis between structure and activity showed that the middle thiophene ring played an important role on the inhibitory activities. It was shown that these compounds could be the potential candidates for new photoactivated pesticides.
2014, 25(2): 337-340
Abstract:
A series of salicylaldimine ligands were designed to promote the copper-catalyzed Ullmann crosscoupling reaction. After a screening process, 2-((2-isopropylphenylimino)methyl)phenol was found to serve as a good supporting ligand for this reaction. Employing this Schiff-base ligand as a new supporting ligand, the copper-catalyzed coupling reactions of aryl bromides and aryl iodides with various phenols successfully proceeded in good yields under mild conditions. Various diaryl ethers were obtained with excellent yields in dioxane in the presence of K3PO4 and a catalytic amount of copper(I) salt.
A series of salicylaldimine ligands were designed to promote the copper-catalyzed Ullmann crosscoupling reaction. After a screening process, 2-((2-isopropylphenylimino)methyl)phenol was found to serve as a good supporting ligand for this reaction. Employing this Schiff-base ligand as a new supporting ligand, the copper-catalyzed coupling reactions of aryl bromides and aryl iodides with various phenols successfully proceeded in good yields under mild conditions. Various diaryl ethers were obtained with excellent yields in dioxane in the presence of K3PO4 and a catalytic amount of copper(I) salt.
2014, 25(2): 341-347
Abstract:
In this study, 1,3-disulfonic acid imidazolium hydrogen sulfate (DSIMHS) is used as an efficient and reusable ionic liquid for the green, mild, and efficient synthesis of xanthenes under solvent-free conditions. Simple and easy work-up, low cost, green process, short reaction times and excellent yields of the products are the advantages of this procedure. Further, the catalyst can be recycled and reused at least for four times without a noticeably decrease in its catalytic activity.
In this study, 1,3-disulfonic acid imidazolium hydrogen sulfate (DSIMHS) is used as an efficient and reusable ionic liquid for the green, mild, and efficient synthesis of xanthenes under solvent-free conditions. Simple and easy work-up, low cost, green process, short reaction times and excellent yields of the products are the advantages of this procedure. Further, the catalyst can be recycled and reused at least for four times without a noticeably decrease in its catalytic activity.
2014, 25(2): 348-350
Abstract:
Polymethoxy-substituted phenanthrene-9-carboxylic acids or theirmethylate are key intermediates for the synthesis of tylophora alkaloids and their analogs. An intramolecular oxidative coupling reaction of unfunctionalized 2,3-disubstituted phenyl acrylic acids and derivatives promoted by di-tert-butylperoxide gave above intermediates in high yields. The mild reaction conditions and easy purification procedures of this method provide a new approach for the synthesis of phenanthrenes.
Polymethoxy-substituted phenanthrene-9-carboxylic acids or theirmethylate are key intermediates for the synthesis of tylophora alkaloids and their analogs. An intramolecular oxidative coupling reaction of unfunctionalized 2,3-disubstituted phenyl acrylic acids and derivatives promoted by di-tert-butylperoxide gave above intermediates in high yields. The mild reaction conditions and easy purification procedures of this method provide a new approach for the synthesis of phenanthrenes.
2014, 25(2): 351-354
Abstract:
A series of novel indole derivatives were designed and synthesized and their inhibitory activity against B-Raf and HepG2 cell were also described. Among them, compounds 7a and 7b exhibited excellent potency, which showed the potential for further research as lead compounds.
A series of novel indole derivatives were designed and synthesized and their inhibitory activity against B-Raf and HepG2 cell were also described. Among them, compounds 7a and 7b exhibited excellent potency, which showed the potential for further research as lead compounds.
2014, 25(2): 355-358
Abstract:
A series of β-cyclodextrin (CDs) functionalized graphene nanohybrids have been successfully fabricated utilizing the classical covalent modification methods at different reaction temperatures. It is very interesting that although both CDs and graphene oxide (GO) could be easily decomposed, the effective combination of GO with CDs leads to significantly enhanced thermal stability of graphene derivatives (GO-CDs). Moreover, the introduction of CDs could dramatically improve the dispersibility promotion of our products in both polar/protic and nonpolar/aprotic solvents, which will contribute to the preparation of polymer nanocomposites and increase of their thermal stability. The improved thermal degradation temperatures can be obtained for polyvinyl alcohol after filling with as little as 1 wt.% of the hybrid. The obtained products could be potentially used in heat-retardant or thermal-control materials.
A series of β-cyclodextrin (CDs) functionalized graphene nanohybrids have been successfully fabricated utilizing the classical covalent modification methods at different reaction temperatures. It is very interesting that although both CDs and graphene oxide (GO) could be easily decomposed, the effective combination of GO with CDs leads to significantly enhanced thermal stability of graphene derivatives (GO-CDs). Moreover, the introduction of CDs could dramatically improve the dispersibility promotion of our products in both polar/protic and nonpolar/aprotic solvents, which will contribute to the preparation of polymer nanocomposites and increase of their thermal stability. The improved thermal degradation temperatures can be obtained for polyvinyl alcohol after filling with as little as 1 wt.% of the hybrid. The obtained products could be potentially used in heat-retardant or thermal-control materials.
2014, 25(2): 359-363
Abstract:
Reduced graphene oxide (RGO) supported ruthenium (Ru) catalyst was prepared by an impregnation method using RuCl3 as a precursor and RGO as a support. The catalyst Ru/RGO was used for the selective hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN), showing a selectivity of 96% at complete conversion of p-CNB at 60 ℃ and 3.0 MPa H2. The Ru/RGO catalyst was extremely active for the hydrogenation of a series of nitroarenes, which can be attributed to the small sized and the fine dispersity of the Ru nanoparticles on the RGO sheets characterized by TEM. Moreover, the catalyst also can be recycled five times without the loss of activity.
Reduced graphene oxide (RGO) supported ruthenium (Ru) catalyst was prepared by an impregnation method using RuCl3 as a precursor and RGO as a support. The catalyst Ru/RGO was used for the selective hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN), showing a selectivity of 96% at complete conversion of p-CNB at 60 ℃ and 3.0 MPa H2. The Ru/RGO catalyst was extremely active for the hydrogenation of a series of nitroarenes, which can be attributed to the small sized and the fine dispersity of the Ru nanoparticles on the RGO sheets characterized by TEM. Moreover, the catalyst also can be recycled five times without the loss of activity.
2014, 25(2): 364-366
Abstract:
In recent years, there has been a pronounced interest in solid-contact ion-selective electrodes (SC-ISEs), with emphasis on the use of conducting polymers as ion-to-electron transducer. In this work, a ladder conjugated polymer, thieno[3,2-b]thiophene (LCPT), was investigated in fabricating Cu2+-selective electrodes for the first time. The resulting electrodes were characterized by electrochemical impedance spectroscopy (EIS), chronopotentiometry, and the water layer test. Results proved that the active LCPT facilitates the ion-to-electron transduction, and avoids the detrimental aqueous layer formed at the interface of SC-ISEs.
In recent years, there has been a pronounced interest in solid-contact ion-selective electrodes (SC-ISEs), with emphasis on the use of conducting polymers as ion-to-electron transducer. In this work, a ladder conjugated polymer, thieno[3,2-b]thiophene (LCPT), was investigated in fabricating Cu2+-selective electrodes for the first time. The resulting electrodes were characterized by electrochemical impedance spectroscopy (EIS), chronopotentiometry, and the water layer test. Results proved that the active LCPT facilitates the ion-to-electron transduction, and avoids the detrimental aqueous layer formed at the interface of SC-ISEs.
2014, 25(2): 367-369
Abstract:
Novel quaternary ammonium cationic gemini surfactants, with two hydrocarbon chains and an adamantane core, were designed and synthesized by three-step reactions from adamantane. The structure of obtained surfactants were confirmed by 1H NMR, FTIR and elements analysis and the surface properties of these surfactants were also studied by surface tension measurements. These target surfactants exhibit much lower critical micelle concentrations (CMC) and higher efficiency in lowering the surface tension of water than typical surfactants.
Novel quaternary ammonium cationic gemini surfactants, with two hydrocarbon chains and an adamantane core, were designed and synthesized by three-step reactions from adamantane. The structure of obtained surfactants were confirmed by 1H NMR, FTIR and elements analysis and the surface properties of these surfactants were also studied by surface tension measurements. These target surfactants exhibit much lower critical micelle concentrations (CMC) and higher efficiency in lowering the surface tension of water than typical surfactants.
2014, 25(2): 370-374
Abstract:
The present study reports a sensitive electro-analytical method for the simultaneous determination of dihydroxybenzene isomers by using a thiadiazole film electrode, which was readily prepared by electropolymerization of 2,5-dimercapto-1,3,4-thiadiazole on a glassy carbon electrode with cyclic voltammetry. The functionalized electrode has a distinguishable and sensitive response to dihydroxybenzene isomers. Under the optimized conditions, the linear stripping peak currents showed good linear relationships with hydroquinone, catechol and resorcinol at concentration ranges 0.50-120, 0.50-110 and 1.00-110 μmol/L, and the detection limits are 0.1, 0.1 and 0.3 μmol/L, respectively. The proposed method is applicable to the simultaneous determination of dihydroxybenzene isomers in real samples with the relative standard deviations of less than 5.7% and the recovery rates of 95.6%-106%. The constructed electrode is characterized by simple preparation, good selectivity, and high sensitivity advantages.
The present study reports a sensitive electro-analytical method for the simultaneous determination of dihydroxybenzene isomers by using a thiadiazole film electrode, which was readily prepared by electropolymerization of 2,5-dimercapto-1,3,4-thiadiazole on a glassy carbon electrode with cyclic voltammetry. The functionalized electrode has a distinguishable and sensitive response to dihydroxybenzene isomers. Under the optimized conditions, the linear stripping peak currents showed good linear relationships with hydroquinone, catechol and resorcinol at concentration ranges 0.50-120, 0.50-110 and 1.00-110 μmol/L, and the detection limits are 0.1, 0.1 and 0.3 μmol/L, respectively. The proposed method is applicable to the simultaneous determination of dihydroxybenzene isomers in real samples with the relative standard deviations of less than 5.7% and the recovery rates of 95.6%-106%. The constructed electrode is characterized by simple preparation, good selectivity, and high sensitivity advantages.
2014, 25(2): 375-379
Abstract:
Amorphous carbon nanoparticles (a-CNPs) on a multi-walled carbon nanotube (MWCNT) film, deposited on a silicon substrate, were synthesized using an electrodeposition combination from a methanol suspension of polydiallyldimethylammonium chloride-modified MWCNTs. A low-voltage electrophoretic deposition of the MWCNTs and a high-voltage electrochemical deposition of the a-CNPs were carried out to yield homogenously attached a-CNPs on the surfaces of the MWCNTs, and form a composite film with good adhesion to the substrate. This scalable technology can produce a large area of a-CNP/MWCNT film. And the field emission investigations show that the a-CNP/MWCNT film has turnon electric field of 3.17 V μm-1 (at 10 μA cm-2) and threshold field of 4.62 V μm-1 (at 1 mA cm-2), which are lower than those of the MWCNT film. The a-CNP/MWCNT film can be deposited simply with large areas and may be a promising cathode material applied in field emission displays.
Amorphous carbon nanoparticles (a-CNPs) on a multi-walled carbon nanotube (MWCNT) film, deposited on a silicon substrate, were synthesized using an electrodeposition combination from a methanol suspension of polydiallyldimethylammonium chloride-modified MWCNTs. A low-voltage electrophoretic deposition of the MWCNTs and a high-voltage electrochemical deposition of the a-CNPs were carried out to yield homogenously attached a-CNPs on the surfaces of the MWCNTs, and form a composite film with good adhesion to the substrate. This scalable technology can produce a large area of a-CNP/MWCNT film. And the field emission investigations show that the a-CNP/MWCNT film has turnon electric field of 3.17 V μm-1 (at 10 μA cm-2) and threshold field of 4.62 V μm-1 (at 1 mA cm-2), which are lower than those of the MWCNT film. The a-CNP/MWCNT film can be deposited simply with large areas and may be a promising cathode material applied in field emission displays.
2014, 25(2): 380-382
Abstract:
In this study, well-dispersed gold nanoparticles were prepared by using intra-molecular reduction of sodium gold sulfite, without using additional reductants and chloride free. The technical parameters including transformation temperature, pH, and concentration were optimized by the single-factor method as 90 ℃, pH 1, and 0.01 mmol/L [Na3Au(SO3)2], respectively. The resultant colloidal transmission electron microscopy images (TEM) and UV-vis absorption spectrophotometer spectra were acquired to check their properties, and the results show this kind of colloidal gold is controlled to 6 nm in sizes and has good stability in solution.
In this study, well-dispersed gold nanoparticles were prepared by using intra-molecular reduction of sodium gold sulfite, without using additional reductants and chloride free. The technical parameters including transformation temperature, pH, and concentration were optimized by the single-factor method as 90 ℃, pH 1, and 0.01 mmol/L [Na3Au(SO3)2], respectively. The resultant colloidal transmission electron microscopy images (TEM) and UV-vis absorption spectrophotometer spectra were acquired to check their properties, and the results show this kind of colloidal gold is controlled to 6 nm in sizes and has good stability in solution.
2014, 25(2): 383-386
Abstract:
Hexagonal single-crystalline cerium carbonate hydroxide (CeCO3OH) precursors with dendrite morphologies have been synthesized by a facile hydrothermal method at 180 ℃ using CeCl3·7H2O as the cerium source, triethylenetetramine as both an alkaline and carbon source, with triethylenetetramine also playing an important role in the formation of the dendrite structure. Polycrystalline ceria (CeO2) have been obtained by calcining the precursor at 500 ℃ for 4 h. The morphology of the precursor was partly maintained during the heating process. The optical absorption spectra indicate the CeO2 nano/microstructures have a direct band gap of 2.92 eV, which is lower than values of the bulk powder due to the quantum size effect. The high absorption in the UV region for CeO2 nano/microstructure indicated that this material was expected to be used as UV-blocking materials.
Hexagonal single-crystalline cerium carbonate hydroxide (CeCO3OH) precursors with dendrite morphologies have been synthesized by a facile hydrothermal method at 180 ℃ using CeCl3·7H2O as the cerium source, triethylenetetramine as both an alkaline and carbon source, with triethylenetetramine also playing an important role in the formation of the dendrite structure. Polycrystalline ceria (CeO2) have been obtained by calcining the precursor at 500 ℃ for 4 h. The morphology of the precursor was partly maintained during the heating process. The optical absorption spectra indicate the CeO2 nano/microstructures have a direct band gap of 2.92 eV, which is lower than values of the bulk powder due to the quantum size effect. The high absorption in the UV region for CeO2 nano/microstructure indicated that this material was expected to be used as UV-blocking materials.
