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2016 Volume 27 Issue 9
2016, 27(9): 1473-1478
doi: 10.1016/j.cclet.2016.03.012
Abstract:
This present work aims to functionalize poly(amidoamine) (PAMAM) dendrimers with various reported adhesive peptides, including Arg-Gly-Asp (RGD), Tyr-Ile-Gly-Ser-Arg (YIGSR), and Ile-Lys-Val-Ala-Val (IKVAV) for enhancing cell responses. The RGD, YIGSR, or IKVAV functionalized PAMAM coated substrate could promote cell adhesion of bone marrow mesenchymal stem cells (BMSCs) within 1 h after incubation. The neurite differentiation and proliferation of pheochromocytoma (PC12) cells were also significantly enhanced after culturing on the peptide functionalized PAMAM dendrimers for two and four days. This peptide functionalized PAMAM dendrimers are considered as the potential candidates for various tissue engineering applications.
This present work aims to functionalize poly(amidoamine) (PAMAM) dendrimers with various reported adhesive peptides, including Arg-Gly-Asp (RGD), Tyr-Ile-Gly-Ser-Arg (YIGSR), and Ile-Lys-Val-Ala-Val (IKVAV) for enhancing cell responses. The RGD, YIGSR, or IKVAV functionalized PAMAM coated substrate could promote cell adhesion of bone marrow mesenchymal stem cells (BMSCs) within 1 h after incubation. The neurite differentiation and proliferation of pheochromocytoma (PC12) cells were also significantly enhanced after culturing on the peptide functionalized PAMAM dendrimers for two and four days. This peptide functionalized PAMAM dendrimers are considered as the potential candidates for various tissue engineering applications.
2016, 27(9): 1479-1484
doi: 10.1016/j.cclet.2016.03.038
Abstract:
A novel porous aromatic framework, PAF-8, derived from tetraphenylsilane as basic building unit, was successfully synthesized via Friedel-Crafts alkylation reaction. This PAF material had high thermal stability as well as high surface area (785 m2 g-1) calculated from the Brunauer-Emmett-Teller (BET) model. Meanwhile, PAF-8 possessed high performances in gas sorption and especially for CO2 separation. 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.
A novel porous aromatic framework, PAF-8, derived from tetraphenylsilane as basic building unit, was successfully synthesized via Friedel-Crafts alkylation reaction. This PAF material had high thermal stability as well as high surface area (785 m2 g-1) calculated from the Brunauer-Emmett-Teller (BET) model. Meanwhile, PAF-8 possessed high performances in gas sorption and especially for CO2 separation. 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.
2016, 27(9): 1485-1489
doi: 10.1016/j.cclet.2016.03.023
Abstract:
Non-aqueous lithium-oxygen (Li-O2) batteries have been considered as the superior energy storage system due to their high-energy density, however, some challenges limit the practical application of Li-O2 batteries. One of them is the lack of stable electrolyte. In this communication, a novel electrolyte with ethylene sulfite (ES) used as solvent for Li-O2 batteries was reported. ES solvent showed low volatility and high electrochemical stability. Without a catalyst in the air-electrode of Li-O2 batteries, the batteries showed high specific capacity, good round-trip efficiency and cycling stability.
Non-aqueous lithium-oxygen (Li-O2) batteries have been considered as the superior energy storage system due to their high-energy density, however, some challenges limit the practical application of Li-O2 batteries. One of them is the lack of stable electrolyte. In this communication, a novel electrolyte with ethylene sulfite (ES) used as solvent for Li-O2 batteries was reported. ES solvent showed low volatility and high electrochemical stability. Without a catalyst in the air-electrode of Li-O2 batteries, the batteries showed high specific capacity, good round-trip efficiency and cycling stability.
2016, 27(9): 1490-1494
doi: 10.1016/j.cclet.2016.04.002
Abstract:
In this study, a facile way has been proposed to prepare transparent, tough and flexible polyacrylamide (PAM) hydrogels which is composed of a dually crosslinked single network by chemical crosslinking of N, N'-methylenebisacrylamide (BIS) and physical crosslinking of hydrophilic hexagonal boron nitride (hBN) nanosheets. The resulting h-BN/PAM nanocomposite hydrogels are highly transparent, and exhibit significantly enhanced mechanical properties compared to the dark (GO)/PAM nanocomposite hydrogels or chemical crosslinking PAM hydrogels. Thus it opens up new opportunities for developing nextgeneration transparent, tough and flexible hydrogels that hold great promise in such important applications as light responsive soft robot and liquid microlenses.
In this study, a facile way has been proposed to prepare transparent, tough and flexible polyacrylamide (PAM) hydrogels which is composed of a dually crosslinked single network by chemical crosslinking of N, N'-methylenebisacrylamide (BIS) and physical crosslinking of hydrophilic hexagonal boron nitride (hBN) nanosheets. The resulting h-BN/PAM nanocomposite hydrogels are highly transparent, and exhibit significantly enhanced mechanical properties compared to the dark (GO)/PAM nanocomposite hydrogels or chemical crosslinking PAM hydrogels. Thus it opens up new opportunities for developing nextgeneration transparent, tough and flexible hydrogels that hold great promise in such important applications as light responsive soft robot and liquid microlenses.
2016, 27(9): 1495-1499
doi: 10.1016/j.cclet.2016.04.006
Abstract:
An organic ultraviolet (UV) ray absorbent, p-aminobenzoic acid (PABA) was intercalated into a Zn-Ti layered double hydroxide (LDH) precursor by an anion-exchange reaction to obtain ZnTi-PABA-LDH, a new organic-inorganic nanocomposite. The structure and the thermal stability of ZnTi-PABA-LDH were characterized by XRD, FT-IR and TG-DTA. The results indicate ZnTi-PABA-LDH, synthesized by this method, exhibit relatively high crystallinity, and markedly enhanced thermal stability of PABA after intercalation into ZnTi-LDH. The UV-vis-NIR spectrophotometric and ESR data show excellent UV ray resistance and greatly decreased photocatalytic activity when PABA is intercalated into the interlayers of the ZnTi-LDH. The studies suggest that ZnTi-PABA-LDH may have potential applications as safe sunscreen materials.
An organic ultraviolet (UV) ray absorbent, p-aminobenzoic acid (PABA) was intercalated into a Zn-Ti layered double hydroxide (LDH) precursor by an anion-exchange reaction to obtain ZnTi-PABA-LDH, a new organic-inorganic nanocomposite. The structure and the thermal stability of ZnTi-PABA-LDH were characterized by XRD, FT-IR and TG-DTA. The results indicate ZnTi-PABA-LDH, synthesized by this method, exhibit relatively high crystallinity, and markedly enhanced thermal stability of PABA after intercalation into ZnTi-LDH. The UV-vis-NIR spectrophotometric and ESR data show excellent UV ray resistance and greatly decreased photocatalytic activity when PABA is intercalated into the interlayers of the ZnTi-LDH. The studies suggest that ZnTi-PABA-LDH may have potential applications as safe sunscreen materials.
2016, 27(9): 1500-1504
doi: 10.1016/j.cclet.2016.03.036
Abstract:
Pd/TiN nanocomposite catalysts were fabricated for one-step selective hydrogenation of phenol to cyclohexanone successfully. High conversion of phenol (99%) and selectivity of cyclohexanone (98%) were obtained at 30℃ and 0.2 MPa H2 for 12 h in the mixed solvents of H2O and CH2Cl2. The Pd nanoparticles were stable in the reaction, and no aggregation was detected after four successive runs. The catalytic activity and selectivity depended on slightly the Pd particle sizes. The generality of the catalysts for this reaction was demonstrated by the selective hydrogenation of phenol derivatives, which showed that the catalyst was selective for the formation of cyclohexanone.
Pd/TiN nanocomposite catalysts were fabricated for one-step selective hydrogenation of phenol to cyclohexanone successfully. High conversion of phenol (99%) and selectivity of cyclohexanone (98%) were obtained at 30℃ and 0.2 MPa H2 for 12 h in the mixed solvents of H2O and CH2Cl2. The Pd nanoparticles were stable in the reaction, and no aggregation was detected after four successive runs. The catalytic activity and selectivity depended on slightly the Pd particle sizes. The generality of the catalysts for this reaction was demonstrated by the selective hydrogenation of phenol derivatives, which showed that the catalyst was selective for the formation of cyclohexanone.
2016, 27(9): 1505-1508
doi: 10.1016/j.cclet.2016.03.016
Abstract:
An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, heteroaromatic thiols and aliphatic thiols can be converted into their corresponding disulfides in good to excellent yields.
An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, heteroaromatic thiols and aliphatic thiols can be converted into their corresponding disulfides in good to excellent yields.
2016, 27(9): 1509-1514
doi: 10.1016/j.cclet.2016.03.030
Abstract:
The object of this study was to evaluate the effect of bioactive glass (BG) size on mineral formation on dentin surfaces. Totally demineralized dentin discs were treated using BG suspensions with different particle sizes:i.e., microscale bioactive glass (m-BG), submicroscale bioactive glass (sm-BG) and nanoscale bioactive glass (n-BG). Field-emission scanning electron microscopy and 3D profile measurement laser microscopy were used to observe the surface morphology and roughness. It was found that all BG particles could promoted mineral formation on dentin surfaces, while plug-like depositions were observed on the dentin discs treated by n-BG and they were more acid-resistant. The present results may imply that n-BG has potential clinical application for dentin hypersensitivity treatment.
The object of this study was to evaluate the effect of bioactive glass (BG) size on mineral formation on dentin surfaces. Totally demineralized dentin discs were treated using BG suspensions with different particle sizes:i.e., microscale bioactive glass (m-BG), submicroscale bioactive glass (sm-BG) and nanoscale bioactive glass (n-BG). Field-emission scanning electron microscopy and 3D profile measurement laser microscopy were used to observe the surface morphology and roughness. It was found that all BG particles could promoted mineral formation on dentin surfaces, while plug-like depositions were observed on the dentin discs treated by n-BG and they were more acid-resistant. The present results may imply that n-BG has potential clinical application for dentin hypersensitivity treatment.
2016, 27(9): 1515-1518
doi: 10.1016/j.cclet.2016.03.026
Abstract:
An efficient and facile approach for tetrachlorosilane as an in situ mediated transformation via a one-pot, synthesis of vicinal bromoazides through the generation of BrN3 from azidochlorosilane and N-bromosuccinimide in acetonitrile as solvent at ambient temperature is achieved. This catalytic process represents a highly regioselective and high yielding method for the synthesis of 1, 2-bromoazides. Thiamine pyrophosphate (TPP) riboswitches regulate essential genes in bacteria by changing conformation upon binding intracellular TPP. Molecular docking studies are conducted to understand the orientation and the interaction of each synthesized molecules with TPP riboswitches. 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.
An efficient and facile approach for tetrachlorosilane as an in situ mediated transformation via a one-pot, synthesis of vicinal bromoazides through the generation of BrN3 from azidochlorosilane and N-bromosuccinimide in acetonitrile as solvent at ambient temperature is achieved. This catalytic process represents a highly regioselective and high yielding method for the synthesis of 1, 2-bromoazides. Thiamine pyrophosphate (TPP) riboswitches regulate essential genes in bacteria by changing conformation upon binding intracellular TPP. Molecular docking studies are conducted to understand the orientation and the interaction of each synthesized molecules with TPP riboswitches. 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.
2016, 27(9): 1519-1522
doi: 10.1016/j.cclet.2016.03.024
Abstract:
A new and convenient procedure is developed for the preparation of N-sulfonylbenzotriazoles from sodium sulfinates and benzotriazoles using molecular iodine as catalyst via the S-N bond formation reaction. This catalytic radical sulfonylation proceeds efficiently in air at room temperature under neutral conditions, and in short reaction time, to afford the corresponding N-sulfonylbenzotriazoles in good yields, thus extending the catalytic application of molecular iodine in organic synthesis.
A new and convenient procedure is developed for the preparation of N-sulfonylbenzotriazoles from sodium sulfinates and benzotriazoles using molecular iodine as catalyst via the S-N bond formation reaction. This catalytic radical sulfonylation proceeds efficiently in air at room temperature under neutral conditions, and in short reaction time, to afford the corresponding N-sulfonylbenzotriazoles in good yields, thus extending the catalytic application of molecular iodine in organic synthesis.
2016, 27(9): 1523-1530
doi: 10.1016/j.cclet.2016.03.029
Abstract:
We synthesised a series of ω-aminoalkyl sodium hydrogen phosphates (AAP-n-Na, n=3, 4, 5, 6, purity>99%), which have potential applications as bioactive cosmetic ingredients and surface modifiers of bone minerals (i.e. hydroxyapatites). Results from Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR) and high resolution mass spectroscopy, and elemental analysis all matched their chemical structures. The acid dissociation constants (pKa's) of each AAP-n (acid form of AAP-n-Na, n=2-6) were measured by potentiometric titration, showing a general increasing trend with an increase in the chain length of AAP-n. However, the pKa3 constant, which corresponds to the deprotonation of the ammonium group in AAP-n-Na, displayed an unusual decrease when n=even. This odd-even effect can be explained by the pairwise self-association of AAP-n-Na molecules in water where intermolecular hydrogen bonding in case of n=even is weaker than that in case of n=odd. All AAP-n-Na at concentrations up to 0.1% (w/v) were non-toxic to L929 fibroblasts and MG 63 osteoblast-like cells in terms of cell growth and morphology. These basic data were important for applications of AAP-n and their salts in biomedical engineering.
We synthesised a series of ω-aminoalkyl sodium hydrogen phosphates (AAP-n-Na, n=3, 4, 5, 6, purity>99%), which have potential applications as bioactive cosmetic ingredients and surface modifiers of bone minerals (i.e. hydroxyapatites). Results from Fourier transformed infrared (FTIR), nuclear magnetic resonance (NMR) and high resolution mass spectroscopy, and elemental analysis all matched their chemical structures. The acid dissociation constants (pKa's) of each AAP-n (acid form of AAP-n-Na, n=2-6) were measured by potentiometric titration, showing a general increasing trend with an increase in the chain length of AAP-n. However, the pKa3 constant, which corresponds to the deprotonation of the ammonium group in AAP-n-Na, displayed an unusual decrease when n=even. This odd-even effect can be explained by the pairwise self-association of AAP-n-Na molecules in water where intermolecular hydrogen bonding in case of n=even is weaker than that in case of n=odd. All AAP-n-Na at concentrations up to 0.1% (w/v) were non-toxic to L929 fibroblasts and MG 63 osteoblast-like cells in terms of cell growth and morphology. These basic data were important for applications of AAP-n and their salts in biomedical engineering.
2016, 27(9): 1531-1536
doi: 10.1016/j.cclet.2016.03.002
Abstract:
CdSe/CdS quantum dots (QDs) functionalized by thiourea (TU) were synthesized and used as a fluorescent sensor for mercury ion detection. The TU-functionalized QDs were prepared by bonding TU via electrostatic interaction to the core/shell CdSe/CdS QDs after capping with thioglycolic acid (TGA). It was observed that the fluorescence of the functionalized QDs was quenched upon the addition of Hg2+. The quantitative detection of Hg2+ with this fluorescent sensor could be conducted based on the linear relationship between the extent of quenching and the concentration of Hg2+ added in the range of 1-300 mg L-1. A detection limit of 0.56 mg L-1 was achieved. The sensor showed superior selectivity for Hg2+ and was successfully applied to the determination of mercury in environmental samples with satisfactory results.
CdSe/CdS quantum dots (QDs) functionalized by thiourea (TU) were synthesized and used as a fluorescent sensor for mercury ion detection. The TU-functionalized QDs were prepared by bonding TU via electrostatic interaction to the core/shell CdSe/CdS QDs after capping with thioglycolic acid (TGA). It was observed that the fluorescence of the functionalized QDs was quenched upon the addition of Hg2+. The quantitative detection of Hg2+ with this fluorescent sensor could be conducted based on the linear relationship between the extent of quenching and the concentration of Hg2+ added in the range of 1-300 mg L-1. A detection limit of 0.56 mg L-1 was achieved. The sensor showed superior selectivity for Hg2+ and was successfully applied to the determination of mercury in environmental samples with satisfactory results.
2016, 27(9): 1537-1540
doi: 10.1016/j.cclet.2016.03.034
Abstract:
To study the intramolecular Diels-Alder cycloadditon of 2H-chromen-2-one as a diene, a series of chiral N-allyl-N-benzylamides that contain a 2H-chromen-2-one moiety were designed for the synthesis of benzo[f]isoindol-1-ones via an intramolecular Diels-Alder and a subsequent retro-Diels-Alder cycloaddition with the expulsion of CO2. Both the yield (80%-89%) and absolute stereocontrol of the tandem reaction were high when an electron-withdrawing group was attached to the dienophile. The double bond in the styrene substructure remained in the products could be further derivatized by dihydroxylation.
To study the intramolecular Diels-Alder cycloadditon of 2H-chromen-2-one as a diene, a series of chiral N-allyl-N-benzylamides that contain a 2H-chromen-2-one moiety were designed for the synthesis of benzo[f]isoindol-1-ones via an intramolecular Diels-Alder and a subsequent retro-Diels-Alder cycloaddition with the expulsion of CO2. Both the yield (80%-89%) and absolute stereocontrol of the tandem reaction were high when an electron-withdrawing group was attached to the dienophile. The double bond in the styrene substructure remained in the products could be further derivatized by dihydroxylation.
2016, 27(9): 1541-1546
doi: 10.1016/j.cclet.2016.07.007
Abstract:
Graphene nanosheets (GS) were easily prepared through liquid-phase exfoliation of graphite powder in N, N-dimethylformamide (DMF) with the assistance of sodium citrate. Then, GS was coated onto a glassy carbon electrode (GCE) surface by drop to fabricate a GS/GCE nanointerface. Subsequently, by using tetraethylorthosilicate sol as precursor, nanosilica was electrochemically deposited onto the GS/GCE surface to produce a nanocomposite film electrode (nanosilica/GS/GCE). Electrochemical behaviors of methyl parathion (MP) on the nanosilica/GS/GCE surface were investigated thoroughly. It was found that the nanosilica/GS nanocomposites can improve the redox peak currents of MP significantly due to the synergetic effect. The oxidation peak current was linearly related to MP concentration in the range from 0.0005 μmol/L to 5.6 μmol/L. The detection limit was calculated to be 0.07 nmol/L (S/N=3). The developed method was used to determine MP in real samples. The recoveries were in the range from 95.4% to 104.2%, demonstrating satisfactory results.
Graphene nanosheets (GS) were easily prepared through liquid-phase exfoliation of graphite powder in N, N-dimethylformamide (DMF) with the assistance of sodium citrate. Then, GS was coated onto a glassy carbon electrode (GCE) surface by drop to fabricate a GS/GCE nanointerface. Subsequently, by using tetraethylorthosilicate sol as precursor, nanosilica was electrochemically deposited onto the GS/GCE surface to produce a nanocomposite film electrode (nanosilica/GS/GCE). Electrochemical behaviors of methyl parathion (MP) on the nanosilica/GS/GCE surface were investigated thoroughly. It was found that the nanosilica/GS nanocomposites can improve the redox peak currents of MP significantly due to the synergetic effect. The oxidation peak current was linearly related to MP concentration in the range from 0.0005 μmol/L to 5.6 μmol/L. The detection limit was calculated to be 0.07 nmol/L (S/N=3). The developed method was used to determine MP in real samples. The recoveries were in the range from 95.4% to 104.2%, demonstrating satisfactory results.
2016, 27(9): 1547-1550
doi: 10.1016/j.cclet.2016.06.019
Abstract:
A series of novel N-(3-furan-2-yl-1-phenyl-1H-pyrazol-5-yl) amides derivatives were designed and synthesized. Their structures were confirmed by 1H NMR, 13C NMR and HRMS. All title compounds were evaluated for their herbicidal and antifungal activities. Preliminary bioassay results indicated that the title compounds showed good to moderate herbicidal activity at 1000 mg/L. Compound 6q presented the best activity against Digitaria sanguinalis (L) Scop., Amaranthus retroflexus L. and Arabidopsis thaliana with an inhibition degree of five. Compound 6d also showed an inhibition degree of five against D. sanguinalis. In addition, at 50 mg/L, most compounds exhibited good in vitro antifungal activity against Sclerotinia sclerotiorum, with compound 6c showing over 90% antifungal activity against S. sclerotiorum and Pellicularia sasakii.
A series of novel N-(3-furan-2-yl-1-phenyl-1H-pyrazol-5-yl) amides derivatives were designed and synthesized. Their structures were confirmed by 1H NMR, 13C NMR and HRMS. All title compounds were evaluated for their herbicidal and antifungal activities. Preliminary bioassay results indicated that the title compounds showed good to moderate herbicidal activity at 1000 mg/L. Compound 6q presented the best activity against Digitaria sanguinalis (L) Scop., Amaranthus retroflexus L. and Arabidopsis thaliana with an inhibition degree of five. Compound 6d also showed an inhibition degree of five against D. sanguinalis. In addition, at 50 mg/L, most compounds exhibited good in vitro antifungal activity against Sclerotinia sclerotiorum, with compound 6c showing over 90% antifungal activity against S. sclerotiorum and Pellicularia sasakii.
2016, 27(9): 1551-1553
doi: 10.1016/j.cclet.2016.02.031
Abstract:
New [1+1] and 62-membered [2+2] Schiff base macrocycles containing a 2, 6-diamidopyridine subunit have been synthesized by condensation reaction of the precursors pyridine-2, 6-dicarboxamide and 1, 10-bis(20-formylphenyloxy)decane in the presence of phosphoric acid via a one-pot process. The cyclocondensed products were effectively isolated by gel column chromatography and characterized by 1H NMR, FTIR, mass spectrometry and X-ray analysis. The two macrocycles have a twisted structure, and not an open ‘circular’ conformation in the solid state.
New [1+1] and 62-membered [2+2] Schiff base macrocycles containing a 2, 6-diamidopyridine subunit have been synthesized by condensation reaction of the precursors pyridine-2, 6-dicarboxamide and 1, 10-bis(20-formylphenyloxy)decane in the presence of phosphoric acid via a one-pot process. The cyclocondensed products were effectively isolated by gel column chromatography and characterized by 1H NMR, FTIR, mass spectrometry and X-ray analysis. The two macrocycles have a twisted structure, and not an open ‘circular’ conformation in the solid state.
2016, 27(9): 1554-1558
doi: 10.1016/j.cclet.2016.06.016
Abstract:
Nitric oxide has played an important role in many physiological and pathological processes as a kind of important gas signal molecules. In this work, a new fluorescent probe LysoNO-Naph for detecting NO in lysosomes based on 1, 8-naphthalimide was reported. LysoNO-Naph has sub-groups of o-phenylenediamine as a NO reaction site and 4-(2-aminoethyl)-morpholine as a lysosome-targetable group. This probe exhibited good selectivity and high sensitivity (4.57 μmol/L) toward NO in a wide pH range from 4 to 12. Furthermore, LysoNO-Naph can be used for imaging NO in lysosomes in living cells.
Nitric oxide has played an important role in many physiological and pathological processes as a kind of important gas signal molecules. In this work, a new fluorescent probe LysoNO-Naph for detecting NO in lysosomes based on 1, 8-naphthalimide was reported. LysoNO-Naph has sub-groups of o-phenylenediamine as a NO reaction site and 4-(2-aminoethyl)-morpholine as a lysosome-targetable group. This probe exhibited good selectivity and high sensitivity (4.57 μmol/L) toward NO in a wide pH range from 4 to 12. Furthermore, LysoNO-Naph can be used for imaging NO in lysosomes in living cells.
2016, 27(9): 1559-1562
doi: 10.1016/j.cclet.2016.02.028
Abstract:
A three-dimensional few-layer reduced graphene oxide-wrapped mesoporous Li4Ti5O12 (m-LTO@FLRGO) electrode is produced using a simple solution fabrication process. When tested as an anode for Liion batteries, the m-LTO@FL-RGO composite exhibits excellent rate capability and superior cycle life. The capacity of m-LTO@FL-RGO reaches 165.4 mA h g-1 after 100 cycles between 1 and 2.5 V at a rate of 1 C. Even at a rate of 30 C, a high discharge capacity of 115.1 mA h g-1 is still obtained, which is three times higher than the pristine mesoporous Li4Ti5O12 (m-LTO). The graphene nanosheets are incorporated into the m-LTO microspheres homogenously, which provide a high conductive network for electron transportation.
A three-dimensional few-layer reduced graphene oxide-wrapped mesoporous Li4Ti5O12 (m-LTO@FLRGO) electrode is produced using a simple solution fabrication process. When tested as an anode for Liion batteries, the m-LTO@FL-RGO composite exhibits excellent rate capability and superior cycle life. The capacity of m-LTO@FL-RGO reaches 165.4 mA h g-1 after 100 cycles between 1 and 2.5 V at a rate of 1 C. Even at a rate of 30 C, a high discharge capacity of 115.1 mA h g-1 is still obtained, which is three times higher than the pristine mesoporous Li4Ti5O12 (m-LTO). The graphene nanosheets are incorporated into the m-LTO microspheres homogenously, which provide a high conductive network for electron transportation.
2016, 27(9): 1563-1566
doi: 10.1016/j.cclet.2016.02.021
Abstract:
We develop a novel coumarin-alkyne derivative (NC7-AL), which can specifically react with Au3+ and give a colorimetric and fluorescent "turn-on" response toward Au3+. Notably, other alkynophilic metal species such as Au+, Ag+, Pd2+, Ni2+, Cu2+, and Hg2+ do not produce an interfering signal. A good linear relationship between emission intensity at 420 nm and Au3+ concentration from 0 to 2 equivalent is observed, and the detection limit (3σ/k) is estimated to be ca. 3.58 nmol/L. Harnessing the Au3+-induced color change from light yellow to colorless, we find that NC7-AL-based modified TLC plate can be used for convenient naked-eye detection of Au3+.
We develop a novel coumarin-alkyne derivative (NC7-AL), which can specifically react with Au3+ and give a colorimetric and fluorescent "turn-on" response toward Au3+. Notably, other alkynophilic metal species such as Au+, Ag+, Pd2+, Ni2+, Cu2+, and Hg2+ do not produce an interfering signal. A good linear relationship between emission intensity at 420 nm and Au3+ concentration from 0 to 2 equivalent is observed, and the detection limit (3σ/k) is estimated to be ca. 3.58 nmol/L. Harnessing the Au3+-induced color change from light yellow to colorless, we find that NC7-AL-based modified TLC plate can be used for convenient naked-eye detection of Au3+.
2016, 27(9): 1567-1571
doi: 10.1016/j.cclet.2016.03.004
Abstract:
Commercialization of acetylene hydrochlorination using AuCl3 catalysts has been impeded by its poor stability. We have been studying that nitrogen-modified Au/NAC catalyst delivered a stable performance which can improve acetylene hydrochlorination activity and has resistance to catalytic deactivation. Here we show that nitrogen and sulfur co-doped activated carbon supported AuCl3 catalyst worked as efficient catalysts for the hydrochlorination of acetylene to vinyl chloride. Au/NSAC catalyst demonstrated high activity comparative to Au/AC catalyst. Furthermore, it also delivered stable performance within the selectivity of acetylene, reaching more than 99.5%, and there was only a 3.3% C2H2 conversion loss after running for 12 h under the reaction conditions of a temperature of 180℃ and a C2H2 hourly space velocity of 1480 h 1. The presence of the sulfur atoms may serve to immobilize/anchor the Au and also help prevent reduction and sintering of the Au and hence improve the catalytic activity and stability. The excellent catalytic performance of the Au/NSAC catalyst demonstrated its potential as an alternative to mercury chloride catalysts for acetylene hydrochlorination.
Commercialization of acetylene hydrochlorination using AuCl3 catalysts has been impeded by its poor stability. We have been studying that nitrogen-modified Au/NAC catalyst delivered a stable performance which can improve acetylene hydrochlorination activity and has resistance to catalytic deactivation. Here we show that nitrogen and sulfur co-doped activated carbon supported AuCl3 catalyst worked as efficient catalysts for the hydrochlorination of acetylene to vinyl chloride. Au/NSAC catalyst demonstrated high activity comparative to Au/AC catalyst. Furthermore, it also delivered stable performance within the selectivity of acetylene, reaching more than 99.5%, and there was only a 3.3% C2H2 conversion loss after running for 12 h under the reaction conditions of a temperature of 180℃ and a C2H2 hourly space velocity of 1480 h 1. The presence of the sulfur atoms may serve to immobilize/anchor the Au and also help prevent reduction and sintering of the Au and hence improve the catalytic activity and stability. The excellent catalytic performance of the Au/NSAC catalyst demonstrated its potential as an alternative to mercury chloride catalysts for acetylene hydrochlorination.
2016, 27(9): 1572-1576
doi: 10.1016/j.cclet.2016.03.003
Abstract:
Zinc telluride/reduced graphene oxide (ZnTe/RGO) nanocomposites are synthesized by a one-pot, facile, solvothermal process using hydrazine hydrate as the reducing agent. Hydrazine hydrate not only promoted the formation of ZnTe nanoparticles but also reduced GO to RGO. The formation of ZnTe/RGO is demonstrated by different techniques. In addition, the experimental results suggest a possible formation mechanism of these nanocomposites. Finally, due to the transfer of the photo-generated electrons between ZnTe and RGO resulting in low electrons/holes recombination, the as-prepared nanocomposites of ZnTe/RGO exhibited strongly enhanced photocatalytic activity for the bleaching of methyl blue (MB) dye under visible light irradiation.
Zinc telluride/reduced graphene oxide (ZnTe/RGO) nanocomposites are synthesized by a one-pot, facile, solvothermal process using hydrazine hydrate as the reducing agent. Hydrazine hydrate not only promoted the formation of ZnTe nanoparticles but also reduced GO to RGO. The formation of ZnTe/RGO is demonstrated by different techniques. In addition, the experimental results suggest a possible formation mechanism of these nanocomposites. Finally, due to the transfer of the photo-generated electrons between ZnTe and RGO resulting in low electrons/holes recombination, the as-prepared nanocomposites of ZnTe/RGO exhibited strongly enhanced photocatalytic activity for the bleaching of methyl blue (MB) dye under visible light irradiation.
