Login In
2017 Volume 80 Issue 9
2017, 80(9): 795-801
Abstract:
In recent years, study on molecular scale electroluminescent devices has made great progress both on molecular components and device fabrication, which has become an important research branch in the field of molecular electronics. In this review, different methods such as scanning tunneling microscopy and nanogap electrodes technique, for measuring electroluminescence from single-molecule junctions are summarized. The recorded spectra could reveal the emitting type of the devices, and what's more, provide a spectroscopic fingerprint of the molecular emitter.
In recent years, study on molecular scale electroluminescent devices has made great progress both on molecular components and device fabrication, which has become an important research branch in the field of molecular electronics. In this review, different methods such as scanning tunneling microscopy and nanogap electrodes technique, for measuring electroluminescence from single-molecule junctions are summarized. The recorded spectra could reveal the emitting type of the devices, and what's more, provide a spectroscopic fingerprint of the molecular emitter.
2017, 80(9): 802-808
Abstract:
Graphene is a two-dimensional material that is compactly packed with sp2 hybridized carbon atoms and is considered as one of the most promising new materials due to its excellent physical and chemical properties. However, because of the irreversible agglomeration tendency of the graphene sheets, the structural properties of the monolayer nanosheets are disappeared easily. Moreover, the surface of the graphene is in an inert state, resulting in weak interaction with other media, making it difficult to disperse uniformly in a polar or non-polar solvent, so the application of graphene is limited. The functionalization of graphene can control its molecular structure, electronic energy level and chemical properties, which can not only inhibit the agglomeration of graphene effectively, but also improve its dispersibility and stability in the solvent, achieving the diversification of graphene-based materials. In this paper, the progress in functionalized of graphene and its composites in application as energy storage materials are reviewed, and the development prospect of functionalized graphene is prospected as well.
Graphene is a two-dimensional material that is compactly packed with sp2 hybridized carbon atoms and is considered as one of the most promising new materials due to its excellent physical and chemical properties. However, because of the irreversible agglomeration tendency of the graphene sheets, the structural properties of the monolayer nanosheets are disappeared easily. Moreover, the surface of the graphene is in an inert state, resulting in weak interaction with other media, making it difficult to disperse uniformly in a polar or non-polar solvent, so the application of graphene is limited. The functionalization of graphene can control its molecular structure, electronic energy level and chemical properties, which can not only inhibit the agglomeration of graphene effectively, but also improve its dispersibility and stability in the solvent, achieving the diversification of graphene-based materials. In this paper, the progress in functionalized of graphene and its composites in application as energy storage materials are reviewed, and the development prospect of functionalized graphene is prospected as well.
2017, 80(9): 809-818, 862
Abstract:
Traditional anti-tumor drugs can cause serious side effects in clinical treatment due to their nonspecific toxicity. Aptamers are a class of small nucleic acid ligands that have high affinity and specificity for their targets. Well-characterized biomarkers, especially those closely related to the development of cancer, can be used as targets for aptamer selection via the SELEX method. The newly obtained aptamers may be able to act as drugs themselves, or conjugate with other chemical drugs, siRNA, and nanoparticles to generate targeted drug delivery systems which can target specific tumor cells, thus minimizing the toxicity to normal cells, reducing the dose needed for treatment and enhancing therapeutic efficacy. In this review, we summarize the current advances in the application of aptamers in tumor targeted therapy with aptamers as anti-tumor drugs, as drug carriers, as RNA-based therapeutic carriers or as targeted ligands for conjugates with nanoparticles.
Traditional anti-tumor drugs can cause serious side effects in clinical treatment due to their nonspecific toxicity. Aptamers are a class of small nucleic acid ligands that have high affinity and specificity for their targets. Well-characterized biomarkers, especially those closely related to the development of cancer, can be used as targets for aptamer selection via the SELEX method. The newly obtained aptamers may be able to act as drugs themselves, or conjugate with other chemical drugs, siRNA, and nanoparticles to generate targeted drug delivery systems which can target specific tumor cells, thus minimizing the toxicity to normal cells, reducing the dose needed for treatment and enhancing therapeutic efficacy. In this review, we summarize the current advances in the application of aptamers in tumor targeted therapy with aptamers as anti-tumor drugs, as drug carriers, as RNA-based therapeutic carriers or as targeted ligands for conjugates with nanoparticles.
2017, 80(9): 819-828
Abstract:
Aptamers are a kind of oligonucleotide sequences (DNA or RNA) obtained by SELEX technique in vitro, which can combine with the targets by folding into a certain space structure for specific adsorption. The function of aptamers is similar to that of antibodies, but they have incomparable advantages, such as a wide range of targets, good specificity and affinity, screening in vitro without animals, easy labeling and modification, good stability, no toxicity and easy to prepare. In recent years, aptamers have been widely used in the fields of analytical chemistry, biochemistry, food safety, clinical diagnosis and especially multi-components detection. In this paper, the applications of aptamers in rapid detection of metal ions, antibiotics, pesticide residues, mycotoxins, proteins, microorganisms and cells were reviewed, the possible limitations and the main problems were discussed, as well as the application trends were prospected in order to provide some supports and references to expand the application of aptamers and related research.
Aptamers are a kind of oligonucleotide sequences (DNA or RNA) obtained by SELEX technique in vitro, which can combine with the targets by folding into a certain space structure for specific adsorption. The function of aptamers is similar to that of antibodies, but they have incomparable advantages, such as a wide range of targets, good specificity and affinity, screening in vitro without animals, easy labeling and modification, good stability, no toxicity and easy to prepare. In recent years, aptamers have been widely used in the fields of analytical chemistry, biochemistry, food safety, clinical diagnosis and especially multi-components detection. In this paper, the applications of aptamers in rapid detection of metal ions, antibiotics, pesticide residues, mycotoxins, proteins, microorganisms and cells were reviewed, the possible limitations and the main problems were discussed, as well as the application trends were prospected in order to provide some supports and references to expand the application of aptamers and related research.
2017, 80(9): 829-834
Abstract:
Sulfonylurea compounds are susceptible to degradation and exist in environmental and biological samples at trace level. It is a great challenge to detect sulfonylurea hebicides. Molecularly imprinted polymers (MIPs) have charateristics of high selectivity and chemical stability. Thus, as a separation and enrichment medium, MIPs have been widely applied in the determination of pesticide residues to improve the accuracy and precision of analytical results. In this paper, the syntheses of sulfonylurea-MIPs for recent 15 years were reviewed according to the following three aspects:monomer, solvent and polymerization method. Moreover, the applications of sulfonylurea-MIPs in residue detection were summarized. It is hoped that this review will provide a reference for detection technology research of sulfonylurea herbicides residues.
Sulfonylurea compounds are susceptible to degradation and exist in environmental and biological samples at trace level. It is a great challenge to detect sulfonylurea hebicides. Molecularly imprinted polymers (MIPs) have charateristics of high selectivity and chemical stability. Thus, as a separation and enrichment medium, MIPs have been widely applied in the determination of pesticide residues to improve the accuracy and precision of analytical results. In this paper, the syntheses of sulfonylurea-MIPs for recent 15 years were reviewed according to the following three aspects:monomer, solvent and polymerization method. Moreover, the applications of sulfonylurea-MIPs in residue detection were summarized. It is hoped that this review will provide a reference for detection technology research of sulfonylurea herbicides residues.
2017, 80(9): 835-844
Abstract:
The differences between isobutane direct dehydrogenation and oxydehydrogenation were summarized from the perspective of thermodynamics and reaction mechanism. The catalysts for the direct dehydrogenation of isobutane to isobutene, including PtSn-、CrOx-、GaOx-base and metal sulfide catalyst, are reviewed in terms of the nature of active center, deactivation-regeneration, the promoters and carriers. The advantages and disadvantages of the catalysts and the current research direction were analyzed. Other types of dehydrogenation catalysts were summarized, including Mo/MgAl2O4, carbon-based material, Co-, Ni2P-, VOx-based catalysts, etc. The problems of current dehydrogenation technology and the future research direction were analyzed.
The differences between isobutane direct dehydrogenation and oxydehydrogenation were summarized from the perspective of thermodynamics and reaction mechanism. The catalysts for the direct dehydrogenation of isobutane to isobutene, including PtSn-、CrOx-、GaOx-base and metal sulfide catalyst, are reviewed in terms of the nature of active center, deactivation-regeneration, the promoters and carriers. The advantages and disadvantages of the catalysts and the current research direction were analyzed. Other types of dehydrogenation catalysts were summarized, including Mo/MgAl2O4, carbon-based material, Co-, Ni2P-, VOx-based catalysts, etc. The problems of current dehydrogenation technology and the future research direction were analyzed.
2017, 80(9): 845-851
Abstract:
In order to improve the sensitivity of LiFePO4 thin films, platinum was selected as doping element to prepare LiFe0.98Pt0.02PO4 powder through hydrothermal method. LiFe0.98Pt0.02PO4 thin film/tin diffused glass optical waveguide was fabricated by immobilizing the doped powder on the surface of the diffused glass using spin coating method, and was further calcinated at different temperatures. The influence of calcination temperature on the optical property and gas sensitivity of LiFe0.98Pt0.02PO4 thin films was discussed by comparing the sensing performances of each film to benzene, toluene, and xylene (BTXs). The experimental results indicated that the LiFe0.98Pt0.02PO4 thin film treated at 450℃ has the characteristics of good transparency, high refractive index, and less attenuation, showing a significant response to BTXs. Meanwhile, the sensor exhibited reversible response to the xylene in the range of 1×10-7~1×10-3 V/V0. When the gas concentration is less than 1×10-6 V/V0, other substances did not interfere with the detection of xylene.
In order to improve the sensitivity of LiFePO4 thin films, platinum was selected as doping element to prepare LiFe0.98Pt0.02PO4 powder through hydrothermal method. LiFe0.98Pt0.02PO4 thin film/tin diffused glass optical waveguide was fabricated by immobilizing the doped powder on the surface of the diffused glass using spin coating method, and was further calcinated at different temperatures. The influence of calcination temperature on the optical property and gas sensitivity of LiFe0.98Pt0.02PO4 thin films was discussed by comparing the sensing performances of each film to benzene, toluene, and xylene (BTXs). The experimental results indicated that the LiFe0.98Pt0.02PO4 thin film treated at 450℃ has the characteristics of good transparency, high refractive index, and less attenuation, showing a significant response to BTXs. Meanwhile, the sensor exhibited reversible response to the xylene in the range of 1×10-7~1×10-3 V/V0. When the gas concentration is less than 1×10-6 V/V0, other substances did not interfere with the detection of xylene.
2017, 80(9): 852-857
Abstract:
Dissolving process of salt mixture (Na2CO3+Na2SO4+NaCl) under different stirring speed, sample amounts and the amount of NaCl at 25℃ was studied. Liquid phase and the equilibrium solid phase were characterized by chemical analysis and solid phase identification, respectively. The results indicated that at the early stage of the dissolution process, the stirring speed act as the dominant factor, but common ion effect will become the dominant factor after reaching a certain concentration of three salts solution. With the increase of sample amounts, Na2CO3 will react with Na2SO4 to form burkeite after reaching a certain concentration. Dissolution kinetics equations for NaCl were obtained with dynamic model simulation, and it conformed to Stumm model under this experimental condition. It is concluded that dissolving process was controlled by diffusion process, but also accompanied by interface reaction and chemical reaction.
Dissolving process of salt mixture (Na2CO3+Na2SO4+NaCl) under different stirring speed, sample amounts and the amount of NaCl at 25℃ was studied. Liquid phase and the equilibrium solid phase were characterized by chemical analysis and solid phase identification, respectively. The results indicated that at the early stage of the dissolution process, the stirring speed act as the dominant factor, but common ion effect will become the dominant factor after reaching a certain concentration of three salts solution. With the increase of sample amounts, Na2CO3 will react with Na2SO4 to form burkeite after reaching a certain concentration. Dissolution kinetics equations for NaCl were obtained with dynamic model simulation, and it conformed to Stumm model under this experimental condition. It is concluded that dissolving process was controlled by diffusion process, but also accompanied by interface reaction and chemical reaction.
2017, 80(9): 858-862
Abstract:
Cefprozil was synthesized using 7-amino-3-[(Z)-all-1-yl]-3-cephem-4-carboxylic acid (7-APCA) as the nucleus, D-hydroxyphenylglycine methyl ester (D-HPGME) as acyl donor, water as solvent via the enzymatic method under the catalysis of immobilized penicillin G acylase. In the study, the carrier of the catalytic enzyme is amino and epoxy polymer. The research screened the appropriate enzyme activity and investigated the influence of several factors including pH, temperature, enzyme dosage, feed ratio and substrate concentration on the synthesis of cefprozil. The data obtained through optimized experiment of synthesizing cefprozil by penicillin G acylase (PGA) lay the foundation for the implementation of the green production technology of cefprozil.
Cefprozil was synthesized using 7-amino-3-[(Z)-all-1-yl]-3-cephem-4-carboxylic acid (7-APCA) as the nucleus, D-hydroxyphenylglycine methyl ester (D-HPGME) as acyl donor, water as solvent via the enzymatic method under the catalysis of immobilized penicillin G acylase. In the study, the carrier of the catalytic enzyme is amino and epoxy polymer. The research screened the appropriate enzyme activity and investigated the influence of several factors including pH, temperature, enzyme dosage, feed ratio and substrate concentration on the synthesis of cefprozil. The data obtained through optimized experiment of synthesizing cefprozil by penicillin G acylase (PGA) lay the foundation for the implementation of the green production technology of cefprozil.
2017, 80(9): 863-867
Abstract:
N1-Substituted 3, 4-dihydropyrimidin-2(1H)-ones were synthesized by a SnCl2 catalysed three components one-pot reaction using aromatic aldehydes, ethyl acetoacetate (methyl acetoacetate) and monosubstituted urea as raw materials under solvent-free conditions. Effects of the amount of catalyst and the reaction temperature on the yields of product were studied. The structures of the titled products were characterized by IR, 1H NMR, 13C NMR and elemental analysis. A mechanism to rationalize the reaction was proposed. This synthetic method has the advantages of short reaction time, mild reaction conditions, high yield, high catalytic activity, inexpensive catalyst and environmentally benign etc.
N1-Substituted 3, 4-dihydropyrimidin-2(1H)-ones were synthesized by a SnCl2 catalysed three components one-pot reaction using aromatic aldehydes, ethyl acetoacetate (methyl acetoacetate) and monosubstituted urea as raw materials under solvent-free conditions. Effects of the amount of catalyst and the reaction temperature on the yields of product were studied. The structures of the titled products were characterized by IR, 1H NMR, 13C NMR and elemental analysis. A mechanism to rationalize the reaction was proposed. This synthetic method has the advantages of short reaction time, mild reaction conditions, high yield, high catalytic activity, inexpensive catalyst and environmentally benign etc.
2017, 80(9): 868-872
Abstract:
The intermediate 2-amino-5-(3-pyridinylmethyl)-1, 3, 4-thiadiazole was prepared from 3-pyridinylacetic acid hydrochloride and thiosemicarbazide by cyclization, followed by reaction with substituted benzoyl chloride to yield the target compound, N-[5-(3-pyridylmethyl)-1, 3, 4-thiadiazol-2-yl]benzamides (3a~3k). Their structures were elucidated by IR, 1H NMR, 13C NMR, MS and elemental analysis. Meanwhile, the target compounds were evaluated for their antifungal activities against B. cinerea by the mycelium growth rate method, and the results indicated that some compounds display antifungal activity to some extent.
The intermediate 2-amino-5-(3-pyridinylmethyl)-1, 3, 4-thiadiazole was prepared from 3-pyridinylacetic acid hydrochloride and thiosemicarbazide by cyclization, followed by reaction with substituted benzoyl chloride to yield the target compound, N-[5-(3-pyridylmethyl)-1, 3, 4-thiadiazol-2-yl]benzamides (3a~3k). Their structures were elucidated by IR, 1H NMR, 13C NMR, MS and elemental analysis. Meanwhile, the target compounds were evaluated for their antifungal activities against B. cinerea by the mycelium growth rate method, and the results indicated that some compounds display antifungal activity to some extent.
2017, 80(9): 873-879
Abstract:
The catalytic property for degradation of phenol wastewater using Fenton reaction of Schiff base manganese complexes{[MnⅢ(salen)(H2O)]2(ClO4)2, [Mn(salen)]2}was studied. The reaction characteristics and mechanism were analyzed by UV analysis, liquid chromatography, double reciprocal mapping and other analytical methods. The experimental results showed that the degradation efficiency of phenol of Fenton reaction is improved with the addition of Mn(salen)2 complex. It maintained a certain degradation ability under different pH systems or excess H2O2. Due to the high valence manganese intermediate, which is converted from the manganese ion in the complex, the oxidation of organic matter and the degradation efficiency have been accelerated. The activation energy of the degradation reaction was reduced by 35.9% after adding the complex into the Fenton system. The catalytic activity of[Mn(salen)]2 remained 60% after 7 times repeat uses.
The catalytic property for degradation of phenol wastewater using Fenton reaction of Schiff base manganese complexes{[MnⅢ(salen)(H2O)]2(ClO4)2, [Mn(salen)]2}was studied. The reaction characteristics and mechanism were analyzed by UV analysis, liquid chromatography, double reciprocal mapping and other analytical methods. The experimental results showed that the degradation efficiency of phenol of Fenton reaction is improved with the addition of Mn(salen)2 complex. It maintained a certain degradation ability under different pH systems or excess H2O2. Due to the high valence manganese intermediate, which is converted from the manganese ion in the complex, the oxidation of organic matter and the degradation efficiency have been accelerated. The activation energy of the degradation reaction was reduced by 35.9% after adding the complex into the Fenton system. The catalytic activity of[Mn(salen)]2 remained 60% after 7 times repeat uses.
2017, 80(9): 880-883
Abstract:
The substance with spinel type structure can insert a large number of alternative ions and change the stoichiometric number in lithium and oxygen, meanwhile, it can keep the stability of spinel type structure. This characteristic can be used for ion exchange study to meet the requirement of extracting lithium. The characteristics of spinel type composite metal oxide can be measured by the value of saturation exchange capacity and distribution coefficient. The spinel type composite Mg1.5Mn0.5Ti0.75O4 was synthesized by the method of co-precipitation/solid state reaction thermal crystallization. The experimental results showed that Mg1.5Mn0.5Ti0.75O4 which was treated by nitric acid can extract more than 72% of Mg2+, while the dissolutions of Mn4+ and Ti4+ were less than 8.2%. The results also indicated that Mg1.5Mn0.5Ti0.75O4 has a good ion-sieve effect on Li+. Its ion exchange capacity for Li+ is up to 10.6 mmol·g-1.
The substance with spinel type structure can insert a large number of alternative ions and change the stoichiometric number in lithium and oxygen, meanwhile, it can keep the stability of spinel type structure. This characteristic can be used for ion exchange study to meet the requirement of extracting lithium. The characteristics of spinel type composite metal oxide can be measured by the value of saturation exchange capacity and distribution coefficient. The spinel type composite Mg1.5Mn0.5Ti0.75O4 was synthesized by the method of co-precipitation/solid state reaction thermal crystallization. The experimental results showed that Mg1.5Mn0.5Ti0.75O4 which was treated by nitric acid can extract more than 72% of Mg2+, while the dissolutions of Mn4+ and Ti4+ were less than 8.2%. The results also indicated that Mg1.5Mn0.5Ti0.75O4 has a good ion-sieve effect on Li+. Its ion exchange capacity for Li+ is up to 10.6 mmol·g-1.
2017, 80(9): 884-887
Abstract:
A practical preparation of artemisone-aminodithioformate hybrid compounds was achieved from dihydroartemisinin and thiomorpholine. The dihydroartemisinin was treated with oxalyl chloride followed by mixing the mixture with a solution of thiomorpholine in dichloromethane, efficiently affording the artemisinin-thiomorpholine complex. Then oxidation of the raw mixture with hydrogen peroxide in the presence of sodium tungstate gave the artemisone 1 with 48% yield for three steps. The artemisone 1 was alkylated with a silyl protected 6-iodo-1-hexanol, then desilylation and iodination of the alkylate compound successfully delivered the corresponding iodide 2α, and the total yield for these three steps was 22.1%. Finally, introduction of the piperazidines into the artemisone motif was realized with carbon disulphide as the linkage, where four artemisone-aminodithioformate hybrid compounds (3a~3d) were obtained from a triethylamine promoted one-pot reaction of iodide 2α, piperazidine and carbon disulphide from room temperature to reflux. The structures of all the synthetic compounds are identified by 1H NMR, 13C NMR, IR and HR-ESI-MS.
A practical preparation of artemisone-aminodithioformate hybrid compounds was achieved from dihydroartemisinin and thiomorpholine. The dihydroartemisinin was treated with oxalyl chloride followed by mixing the mixture with a solution of thiomorpholine in dichloromethane, efficiently affording the artemisinin-thiomorpholine complex. Then oxidation of the raw mixture with hydrogen peroxide in the presence of sodium tungstate gave the artemisone 1 with 48% yield for three steps. The artemisone 1 was alkylated with a silyl protected 6-iodo-1-hexanol, then desilylation and iodination of the alkylate compound successfully delivered the corresponding iodide 2α, and the total yield for these three steps was 22.1%. Finally, introduction of the piperazidines into the artemisone motif was realized with carbon disulphide as the linkage, where four artemisone-aminodithioformate hybrid compounds (3a~3d) were obtained from a triethylamine promoted one-pot reaction of iodide 2α, piperazidine and carbon disulphide from room temperature to reflux. The structures of all the synthetic compounds are identified by 1H NMR, 13C NMR, IR and HR-ESI-MS.
