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2020 Volume 31 Issue 3
2020, 31(3): 589-600
doi: 10.1016/j.cclet.2019.09.022
Abstract:
Most of the current analytical methods depend largely on laboratory-based analytical techniques that require expensive and bulky equipment, potentially incur costly testing, and involve lengthy detection processes. With increasing requirements for point-of-care testing (POCT), more attention has been paid to miniaturized analytical devices. Miniaturized electrochemical (MEC) sensors, including different material-based MEC sensors (such as DNA-, paper-, and screen electrode-based), have been in strong demand in analytical science due to their easy operation, portability, high sensitivity, as well as their short analysis time. They have been applied for the detection of trace amounts of target through measuring changes in electrochemical signal, such as current, voltage, potential, or impedance, due to the oxidation/reduction of chemical/biological molecules with the help of electrodes and electrochemical units. MEC sensors present great potential for the detection of targets including small organic molecules, metal ions, and biomolecules. In recent years, MEC sensors have been broadly applied to POCT in various fields, including health care, food safety, and environmental monitoring, owing to the excellent advantages of electrochemical (EC) technologies. This review summarized the state-of-the-art advancements on various types of MEC sensors and their applications in POCT. Furthermore, the future perspectives, opportunities, and challenges in this field are also discussed.
Most of the current analytical methods depend largely on laboratory-based analytical techniques that require expensive and bulky equipment, potentially incur costly testing, and involve lengthy detection processes. With increasing requirements for point-of-care testing (POCT), more attention has been paid to miniaturized analytical devices. Miniaturized electrochemical (MEC) sensors, including different material-based MEC sensors (such as DNA-, paper-, and screen electrode-based), have been in strong demand in analytical science due to their easy operation, portability, high sensitivity, as well as their short analysis time. They have been applied for the detection of trace amounts of target through measuring changes in electrochemical signal, such as current, voltage, potential, or impedance, due to the oxidation/reduction of chemical/biological molecules with the help of electrodes and electrochemical units. MEC sensors present great potential for the detection of targets including small organic molecules, metal ions, and biomolecules. In recent years, MEC sensors have been broadly applied to POCT in various fields, including health care, food safety, and environmental monitoring, owing to the excellent advantages of electrochemical (EC) technologies. This review summarized the state-of-the-art advancements on various types of MEC sensors and their applications in POCT. Furthermore, the future perspectives, opportunities, and challenges in this field are also discussed.
2020, 31(3): 601-604
doi: 10.1016/j.cclet.2019.05.016
Abstract:
Developing large scale deposition techniques to fabricate thin porous films with suitable opto-electronic properties for water catalysis is a necessity to mitigate climate change and have a sustainable environment. In this review, flame spray pyrolysis (FSP) technique, a rapid and scalable methodology to synthesize nanostructured transitional metal oxide films with designed functionalities, is firstly introduced. Furthermore, applications in electrochemical (EC) and photoelectrochemical (PEC) water splitting for the production of hydrogen fuel is also presented. The high combustion temperature and the aggregation of flame aerosol ensure that the FSP-made films possess high crystallinity, tunable porosity and high surface areas, making this method suitable either as catalysts for EC water splitting or as efficient semiconductor materials for PEC water splitting. Finally, a perspective on the next generation FSP engineered films with potential applications in energy storage and conversion is described.
Developing large scale deposition techniques to fabricate thin porous films with suitable opto-electronic properties for water catalysis is a necessity to mitigate climate change and have a sustainable environment. In this review, flame spray pyrolysis (FSP) technique, a rapid and scalable methodology to synthesize nanostructured transitional metal oxide films with designed functionalities, is firstly introduced. Furthermore, applications in electrochemical (EC) and photoelectrochemical (PEC) water splitting for the production of hydrogen fuel is also presented. The high combustion temperature and the aggregation of flame aerosol ensure that the FSP-made films possess high crystallinity, tunable porosity and high surface areas, making this method suitable either as catalysts for EC water splitting or as efficient semiconductor materials for PEC water splitting. Finally, a perspective on the next generation FSP engineered films with potential applications in energy storage and conversion is described.
2020, 31(3): 605-608
doi: 10.1016/j.cclet.2019.05.054
Abstract:
In this review, development of supported catalysts for the dehydrogenative synthesis of benzimidazoles from primary alcohols and 1, 2-phenylenediamine derivatives is briefly summarized. Among them, titania-supported iridium catalysts showed excellent activities under mild reaction conditions. Remarkably, the low-temperature activity of iridium catalyst was significantly affected by titania supports, and the reaction of 1, 2-phenylenediamine and benzyl alcohol in the presence of rutilesupported catalysts proceeded smoothly at 100 ℃ to give 2-phenylbenzimidazole in high yields of up to 88%. On the other hand, catalysts supported on anatase generally showed poor activity at 100 ℃. A significant relationship between CO uptake and the activity of titania-supported catalysts has been reported, indicating that well-reduced iridium species on rutile would be responsible for the predominant catalytic activity. The present results suggest the importance of the selection of suitable titania supports for the iridium catalysts.
In this review, development of supported catalysts for the dehydrogenative synthesis of benzimidazoles from primary alcohols and 1, 2-phenylenediamine derivatives is briefly summarized. Among them, titania-supported iridium catalysts showed excellent activities under mild reaction conditions. Remarkably, the low-temperature activity of iridium catalyst was significantly affected by titania supports, and the reaction of 1, 2-phenylenediamine and benzyl alcohol in the presence of rutilesupported catalysts proceeded smoothly at 100 ℃ to give 2-phenylbenzimidazole in high yields of up to 88%. On the other hand, catalysts supported on anatase generally showed poor activity at 100 ℃. A significant relationship between CO uptake and the activity of titania-supported catalysts has been reported, indicating that well-reduced iridium species on rutile would be responsible for the predominant catalytic activity. The present results suggest the importance of the selection of suitable titania supports for the iridium catalysts.
2020, 31(3): 609-616
doi: 10.1016/j.cclet.2019.06.013
Abstract:
The lithium metal battery has been considered as a promising candidate for next generation batteries. However, safety concerns caused by uncontrollable lithium dendrite growth on lithium anode are severely hampering the commercial application. Metal-organic frameworks (MOFs) become one of the most attractive materials due to the high porosity, structural designability and tunability. With unique open channels and pores as well as functional components in MOFs, the transportation and deposition of lithium ions can be regulated, which leads to enhanced electrochemical properties. Various strategies for lithium metal protection are proposed in recent works on applications of MOFs in lithium metal batteries. In this review, we highlight latest key approaches in this field and discuss the prospects for MOFs in advanced Li anodes.
The lithium metal battery has been considered as a promising candidate for next generation batteries. However, safety concerns caused by uncontrollable lithium dendrite growth on lithium anode are severely hampering the commercial application. Metal-organic frameworks (MOFs) become one of the most attractive materials due to the high porosity, structural designability and tunability. With unique open channels and pores as well as functional components in MOFs, the transportation and deposition of lithium ions can be regulated, which leads to enhanced electrochemical properties. Various strategies for lithium metal protection are proposed in recent works on applications of MOFs in lithium metal batteries. In this review, we highlight latest key approaches in this field and discuss the prospects for MOFs in advanced Li anodes.
2020, 31(3): 617-625
doi: 10.1016/j.cclet.2019.07.033
Abstract:
Resorbable polymer electrospun nanofiber-based materials/devices have high surface-to-volume ratio and often have a porous structure with excellent pore interconnectivity, which are suitable for growth and development of different types of cells. Due to the huge advantages of both resorbable polymers and electrospun nanofibers, resorbable polymer electrospun nanofibers (RPENs) have been widely applied in the field of tissue engineering. In this paper, we will mainly introduce RPENs for tissue engineering. Firstly, the electrospinning technique and electrospun nanofiber architectures are briefly introduced. Secondly, the application of RPENs in the field of tissue engineering is mainly reviewed. Finally, the advantages and disadvantages of RPENs for tissue engineering are discussed. This review will provide a comprehensive guide to apply resorbable polymer electrospun nanofibers for tissue engineering.
Resorbable polymer electrospun nanofiber-based materials/devices have high surface-to-volume ratio and often have a porous structure with excellent pore interconnectivity, which are suitable for growth and development of different types of cells. Due to the huge advantages of both resorbable polymers and electrospun nanofibers, resorbable polymer electrospun nanofibers (RPENs) have been widely applied in the field of tissue engineering. In this paper, we will mainly introduce RPENs for tissue engineering. Firstly, the electrospinning technique and electrospun nanofiber architectures are briefly introduced. Secondly, the application of RPENs in the field of tissue engineering is mainly reviewed. Finally, the advantages and disadvantages of RPENs for tissue engineering are discussed. This review will provide a comprehensive guide to apply resorbable polymer electrospun nanofibers for tissue engineering.
2020, 31(3): 626-634
doi: 10.1016/j.cclet.2019.08.008
Abstract:
2020, 31(3): 635-642
doi: 10.1016/j.cclet.2019.08.021
Abstract:
Metal-organic frameworks (MOFs) are a class of outstanding materials in Li-air batteries because of their high surface areas, tailorable pore sizes and diverse catalytic centers. However, MOF-based batteries are facing challenges such as poor electronic conductivity and inferior long-cycle stability that limit their further development. This review first summarizes the progress of pristine MOFs and MOF-derived materials in Li-air batteries in the past 5 years, then provides a perspective for subsequent development of MOFs and their derivatives in this emerging field.
Metal-organic frameworks (MOFs) are a class of outstanding materials in Li-air batteries because of their high surface areas, tailorable pore sizes and diverse catalytic centers. However, MOF-based batteries are facing challenges such as poor electronic conductivity and inferior long-cycle stability that limit their further development. This review first summarizes the progress of pristine MOFs and MOF-derived materials in Li-air batteries in the past 5 years, then provides a perspective for subsequent development of MOFs and their derivatives in this emerging field.
2020, 31(3): 643-653
doi: 10.1016/j.cclet.2019.08.022
Abstract:
Indoor photovoltaics have attracted increasing attentions owing to their great potential in supplying energy for low power devices under indoor light in our daily life. The third generation thin-film solar cells, including dye-sensitized solar cells, perovskite solar cells and organic solar cells, have made rapid progress from the aspect of materials design to photovoltaic performance. This review provides an overview on the recent advances in the development of indoor photovoltaic technologies based on the third generation solar cells. The design principles of advanced thin-film indoor photovoltaics were also summarized according to the characteristics of indoor light and the advantages of the third generation solar cells. Finally, after summarizing the current research progress, the perspective on this topic is provided.
Indoor photovoltaics have attracted increasing attentions owing to their great potential in supplying energy for low power devices under indoor light in our daily life. The third generation thin-film solar cells, including dye-sensitized solar cells, perovskite solar cells and organic solar cells, have made rapid progress from the aspect of materials design to photovoltaic performance. This review provides an overview on the recent advances in the development of indoor photovoltaic technologies based on the third generation solar cells. The design principles of advanced thin-film indoor photovoltaics were also summarized according to the characteristics of indoor light and the advantages of the third generation solar cells. Finally, after summarizing the current research progress, the perspective on this topic is provided.
2020, 31(3): 654-666
doi: 10.1016/j.cclet.2019.06.002
Abstract:
Silicon (Si) materials as anode materials for applications in lithium-ion batteries (LIBs) have received increasing attention. Among the Si materials, the electrochemical properties of SiOx-based (0 < x ≤ 2) composites are the most prominent. However, due to the cycling stability of SiOx being far from practical, there are some problems, such as low initial coulombic efficiency (ICE), obvious volume expansion and poor conductivity. Researchers in various countries have optimized the electrochemical properties of SiOx-based composites by means of pore formation, surface modification, and the choice of constituents. In this review, SiOx-based composites are classified into three categories based on the valency of Si (SiO2 composites, SiO composites and SiOx (0 < x < 2) composites). The synthesis, morphologies and electrochemical properties of the SiOx-based composites that are applied in LIB are discussed. Finally, the properties of several common SiOx-based composites are briefly compared and the challenges faced by SiOx-based composites are highlight.
Silicon (Si) materials as anode materials for applications in lithium-ion batteries (LIBs) have received increasing attention. Among the Si materials, the electrochemical properties of SiOx-based (0 < x ≤ 2) composites are the most prominent. However, due to the cycling stability of SiOx being far from practical, there are some problems, such as low initial coulombic efficiency (ICE), obvious volume expansion and poor conductivity. Researchers in various countries have optimized the electrochemical properties of SiOx-based composites by means of pore formation, surface modification, and the choice of constituents. In this review, SiOx-based composites are classified into three categories based on the valency of Si (SiO2 composites, SiO composites and SiOx (0 < x < 2) composites). The synthesis, morphologies and electrochemical properties of the SiOx-based composites that are applied in LIB are discussed. Finally, the properties of several common SiOx-based composites are briefly compared and the challenges faced by SiOx-based composites are highlight.
2020, 31(3): 667-672
doi: 10.1016/j.cclet.2019.07.053
Abstract:
In this work, the protic ionic liquid [DBUH] [Im] (1, 8-diazabicyclo[5.4.0]-7-undeceniumimidazolide) was developed as an efficient catalyst for the transesterification of ethylene carbonate with methanol to produce dimethyl carbonate. At 70 ℃, up to 97% conversion of ethylene carbonate and 91% yield of dimethyl carbonate were obtained with 1 mol% [DBUH] [Im] (relative to ethylene carbonate) as catalyst in 2 h. Even at room temperature, the conversion of ethylene carbonate can reach 94% and the yield of dimethyl carbonate can approach 81% for 6 h. Catalytic mechanism investigation showed the high catalytic efficiency of this ionic liquid results from the synergistic activation effect, wherein the cation can activate ethylene carbonate and the anion can activate methanol through hydrogen bond formation. Although the reusability of the ionic liquid need to be further improved, high efficiency and commercial availability of [DBUH] [Im] render it a promising catalyst for the preparation of dimethyl carbonate.
In this work, the protic ionic liquid [DBUH] [Im] (1, 8-diazabicyclo[5.4.0]-7-undeceniumimidazolide) was developed as an efficient catalyst for the transesterification of ethylene carbonate with methanol to produce dimethyl carbonate. At 70 ℃, up to 97% conversion of ethylene carbonate and 91% yield of dimethyl carbonate were obtained with 1 mol% [DBUH] [Im] (relative to ethylene carbonate) as catalyst in 2 h. Even at room temperature, the conversion of ethylene carbonate can reach 94% and the yield of dimethyl carbonate can approach 81% for 6 h. Catalytic mechanism investigation showed the high catalytic efficiency of this ionic liquid results from the synergistic activation effect, wherein the cation can activate ethylene carbonate and the anion can activate methanol through hydrogen bond formation. Although the reusability of the ionic liquid need to be further improved, high efficiency and commercial availability of [DBUH] [Im] render it a promising catalyst for the preparation of dimethyl carbonate.
2020, 31(3): 673-676
doi: 10.1016/j.cclet.2019.07.061
Abstract:
Absolute one-handed chiral quinoline tetramers andoctamers containing different oxazolylanilines at the C-terminus have been synthesized. The absolute one-handed sense and diastereomeric excess values were valued by 1H NMR. X-ray crystal diffractionand CD studies reveal that the S-oxazolylaniline always induces a P-handed helicity and the absolute helicity is driven by the stable three-center hydrogen bonding between protons in the amide and N atoms in oxazolylaniline and adjacent quinoline ring. CPL investigations demonstrated that S-CQn-a~d are CPL active and its glum values are dependent on its length. Interestingly, the sizes of the substituents in the chiral centers are different, however, they exert no effect on the dissymmetric factors gabs and glum of quinoline oligoamide foldamers.
Absolute one-handed chiral quinoline tetramers andoctamers containing different oxazolylanilines at the C-terminus have been synthesized. The absolute one-handed sense and diastereomeric excess values were valued by 1H NMR. X-ray crystal diffractionand CD studies reveal that the S-oxazolylaniline always induces a P-handed helicity and the absolute helicity is driven by the stable three-center hydrogen bonding between protons in the amide and N atoms in oxazolylaniline and adjacent quinoline ring. CPL investigations demonstrated that S-CQn-a~d are CPL active and its glum values are dependent on its length. Interestingly, the sizes of the substituents in the chiral centers are different, however, they exert no effect on the dissymmetric factors gabs and glum of quinoline oligoamide foldamers.
2020, 31(3): 677-680
doi: 10.1016/j.cclet.2019.08.011
Abstract:
Hydroxyphosphoric acids display the unique biological activities, and they have some attractive prospects as clinical drug moleculars. Herein, a new approach for the synthesis of γ-oxo-phosphonates (the precursor of hydroxyphosphoric acid) has been established through the semipinacol rearrangement tactic involved the photo-induced phosphorus radical process. Most important, this transformation is avoid of the external oxidants, and occurs very well under the sunlight irradiation, meanwhile the γ-oxo-phosphonate was easily derivatized to obtain γ-hydroxyphosphoric acid, thus highlights the synthesis value of this method.
Hydroxyphosphoric acids display the unique biological activities, and they have some attractive prospects as clinical drug moleculars. Herein, a new approach for the synthesis of γ-oxo-phosphonates (the precursor of hydroxyphosphoric acid) has been established through the semipinacol rearrangement tactic involved the photo-induced phosphorus radical process. Most important, this transformation is avoid of the external oxidants, and occurs very well under the sunlight irradiation, meanwhile the γ-oxo-phosphonate was easily derivatized to obtain γ-hydroxyphosphoric acid, thus highlights the synthesis value of this method.
2020, 31(3): 681-684
doi: 10.1016/j.cclet.2019.08.018
Abstract:
Spirooxindoles play an important role in drug discovery and development. The development of efficient methods for the synthesis of spirooxindoles from easily available starting materials is of current interest. Herein, we report in detail the In(OTf)3-catalyzed [3 + 3] annulation of spirocyclopropyl oxindoles and 1, 4-di-thiane-2, 5-diol, which allows the facile preparation of spiro[indoline-3, 4'-thiopyran]-2-ones bearing (tetrahydro)thiopyran skeleton.
Spirooxindoles play an important role in drug discovery and development. The development of efficient methods for the synthesis of spirooxindoles from easily available starting materials is of current interest. Herein, we report in detail the In(OTf)3-catalyzed [3 + 3] annulation of spirocyclopropyl oxindoles and 1, 4-di-thiane-2, 5-diol, which allows the facile preparation of spiro[indoline-3, 4'-thiopyran]-2-ones bearing (tetrahydro)thiopyran skeleton.
2020, 31(3): 685-688
doi: 10.1016/j.cclet.2019.08.033
Abstract:
Efficient synthetic routs for the direct and rapid construction of [5-6-6] ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully developed. For the daphmanidin A-type, the synthesis of [5-6-6] tricyclic framework utilize a HCl-mediated intramolecular Aldol reaction to construct the bicyclo[2.2.2]octane core and a thermal condensation to afford the ABC ring system. In addition, for the calyciphylline A-type, an improved synthesis of ABC [5-6-6] tricyclic system was developed, featuring an introduction of methyl ester group at C2 before the Pd-catalyzed intramolecular oxidative alkylation to construct the desired bowl-shape tricyclic core with stereochemical control.
Efficient synthetic routs for the direct and rapid construction of [5-6-6] ABC tricyclic systems of daphmanidin A-type and calyciphylline A-type alkaloids have been successfully developed. For the daphmanidin A-type, the synthesis of [5-6-6] tricyclic framework utilize a HCl-mediated intramolecular Aldol reaction to construct the bicyclo[2.2.2]octane core and a thermal condensation to afford the ABC ring system. In addition, for the calyciphylline A-type, an improved synthesis of ABC [5-6-6] tricyclic system was developed, featuring an introduction of methyl ester group at C2 before the Pd-catalyzed intramolecular oxidative alkylation to construct the desired bowl-shape tricyclic core with stereochemical control.
2020, 31(3): 689-692
doi: 10.1016/j.cclet.2019.08.036
Abstract:
Here we described the design and synthesis of a discrete 3D amphiphilic metallacage 4, in which the tetragonal prismatic frameworks act as the hydrophobic cores and the poly(ethylene glycol) (PEG) chains as the hydrophilic tails. The structure of 4 was characterized by 1H NMR, 31P NMR and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). Notably, 4 with its long PEG tails was subsequently ordered into micelles at a low concentration (1.20 ×10-6 mol/L) in water. As the concentration and cultivation time increased, the micelles can further self-assembly into nanofibers and nanoribbons. Considering the dynamic property of the coordination bond, these structures show reversible transformation under external stimuli.
Here we described the design and synthesis of a discrete 3D amphiphilic metallacage 4, in which the tetragonal prismatic frameworks act as the hydrophobic cores and the poly(ethylene glycol) (PEG) chains as the hydrophilic tails. The structure of 4 was characterized by 1H NMR, 31P NMR and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). Notably, 4 with its long PEG tails was subsequently ordered into micelles at a low concentration (1.20 ×10-6 mol/L) in water. As the concentration and cultivation time increased, the micelles can further self-assembly into nanofibers and nanoribbons. Considering the dynamic property of the coordination bond, these structures show reversible transformation under external stimuli.
2020, 31(3): 693-696
doi: 10.1016/j.cclet.2019.08.039
Abstract:
The deletion of the C-terminal arginine of the anaphylatoxin protein C5a reduces it receptor binding affinity. Understanding how C-terminal arginine affects the structure and bioactivity of C5a is important for the development of C5a C-terminal mimics as drug candidates. Herein, we report the total chemical synthesis of rat C5a and its D-enantiomer with its C-terminal arginine deleted, namely L-rC5a-desArg and D-rC5a-desArg. The structure of rC5a-desArg was then determined by racemic crystallography for the first time. The C-terminal residues of rC5a-Arg were found to expand from the fourth helix in a continuous helical conformation. This C-terminal conformation is significantly different from that of the previously reported full-length of C5a, indicating that the deletion of C-terminal arginine residue could result in the destruction of a positively charged surface formed by two adjacent Arg residues in C5a.
The deletion of the C-terminal arginine of the anaphylatoxin protein C5a reduces it receptor binding affinity. Understanding how C-terminal arginine affects the structure and bioactivity of C5a is important for the development of C5a C-terminal mimics as drug candidates. Herein, we report the total chemical synthesis of rat C5a and its D-enantiomer with its C-terminal arginine deleted, namely L-rC5a-desArg and D-rC5a-desArg. The structure of rC5a-desArg was then determined by racemic crystallography for the first time. The C-terminal residues of rC5a-Arg were found to expand from the fourth helix in a continuous helical conformation. This C-terminal conformation is significantly different from that of the previously reported full-length of C5a, indicating that the deletion of C-terminal arginine residue could result in the destruction of a positively charged surface formed by two adjacent Arg residues in C5a.
2020, 31(3): 697-700
doi: 10.1016/j.cclet.2019.08.040
Abstract:
An efficient asymmetric and enantio-swithchable organocatalytic[3 + 3] annulation reaction using MBH-2-naphthoates of nitroalkenes and 4-hydroxyquinolin-2(1H)-ones has been developed. Densely substituted tetrahydropyrano[3, 2-c]quinolinones scaffolds with two adjacent stereogenic centers are obtained with high yield (up to 95% yield) and good stereoselectivities (up to > 20:1 dr and 96% ee) in an enantio-switchable manner. Furthermore, gram scale synthesis was achieved and the nitro group could easily transform into an amino group without any appreciable loss in the diastereo-and enantioselectivity.
An efficient asymmetric and enantio-swithchable organocatalytic[3 + 3] annulation reaction using MBH-2-naphthoates of nitroalkenes and 4-hydroxyquinolin-2(1H)-ones has been developed. Densely substituted tetrahydropyrano[3, 2-c]quinolinones scaffolds with two adjacent stereogenic centers are obtained with high yield (up to 95% yield) and good stereoselectivities (up to > 20:1 dr and 96% ee) in an enantio-switchable manner. Furthermore, gram scale synthesis was achieved and the nitro group could easily transform into an amino group without any appreciable loss in the diastereo-and enantioselectivity.
2020, 31(3): 701-705
doi: 10.1016/j.cclet.2019.08.049
Abstract:
Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography. The designed iridium complexes revealed surprisingly high catalytic activity in C-N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions. In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols, N, N'-(phenylmethylene)dibenzamide products were unexpectedly isolated under non-coordinating anion conditions, whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions. The mechanism explorations excluded the possibility of "silver effect" (silver-assisted or bimetallic catalysis) and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions. This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C-N bond formation.
Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography. The designed iridium complexes revealed surprisingly high catalytic activity in C-N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions. In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols, N, N'-(phenylmethylene)dibenzamide products were unexpectedly isolated under non-coordinating anion conditions, whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions. The mechanism explorations excluded the possibility of "silver effect" (silver-assisted or bimetallic catalysis) and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions. This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C-N bond formation.
2020, 31(3): 706-710
doi: 10.1016/j.cclet.2019.08.053
Abstract:
Botrytis cinerea is a necrotrophic fungus that affects various plant species. Chemical control is a necessity and as much as possible, eco-friendly conditions and bioresources to obtain these chemicals should be used. In this context, a series of products was obtained from salicylaldehyde using zinc as a powerful reagent and tested for antifungal activity against Botrytis cinerea.
Botrytis cinerea is a necrotrophic fungus that affects various plant species. Chemical control is a necessity and as much as possible, eco-friendly conditions and bioresources to obtain these chemicals should be used. In this context, a series of products was obtained from salicylaldehyde using zinc as a powerful reagent and tested for antifungal activity against Botrytis cinerea.
2020, 31(3): 711-714
doi: 10.1016/j.cclet.2019.08.052
Abstract:
The 1, 2-dibromoethane-and KI-mediated α-acyloxylation of ketones is reported in moderate to good yield without the use of transition metals and strong oxidants. Various acids are well tolerated with wide functional group compatibility. An 1, 2-dibromoethane-and KI-catalysed reaction mechanism is proposed based on the results of control experiments.
The 1, 2-dibromoethane-and KI-mediated α-acyloxylation of ketones is reported in moderate to good yield without the use of transition metals and strong oxidants. Various acids are well tolerated with wide functional group compatibility. An 1, 2-dibromoethane-and KI-catalysed reaction mechanism is proposed based on the results of control experiments.
2020, 31(3): 715-720
doi: 10.1016/j.cclet.2019.09.001
Abstract:
This research reports a novel heterogeneous Fenton-like catalyst which could freely move through the model sediments and easily seize the pollutants in addition to efficiently catalyze H2O2, well suitable for soil and groundwater remediation. Herein, submicron γ-Fe2O3/C spheres were synthesized through a facile one-step aerosol-based process. In a series of column tests, these spheres exhibit better transport ability due to their optimal size, conforming to the prediction by the Tufenkji-Elimelech filtration theory. Meanwhile, γ-Fe2O3/C spheres could act as a strong adsorbent for organic pollutants owing to the presence of carbon, thereby providing a driving force to gather contaminants into their vicinity and facilitating the reaction. In addition, immobilization of γ-Fe2O3 nanoparticles into carbon spheres protects iron oxides from aggregation, and thus retains the number of active sites for catalytic decomposition of H2O2. Hence, the system containing the as-prepared γ-Fe2O3/C spheres and H2O2 shows the high removal efficiency and degradation efficiency in the remediation of recalcitrant organic contaminants such as methylene blue and sulfamethoxazole.
This research reports a novel heterogeneous Fenton-like catalyst which could freely move through the model sediments and easily seize the pollutants in addition to efficiently catalyze H2O2, well suitable for soil and groundwater remediation. Herein, submicron γ-Fe2O3/C spheres were synthesized through a facile one-step aerosol-based process. In a series of column tests, these spheres exhibit better transport ability due to their optimal size, conforming to the prediction by the Tufenkji-Elimelech filtration theory. Meanwhile, γ-Fe2O3/C spheres could act as a strong adsorbent for organic pollutants owing to the presence of carbon, thereby providing a driving force to gather contaminants into their vicinity and facilitating the reaction. In addition, immobilization of γ-Fe2O3 nanoparticles into carbon spheres protects iron oxides from aggregation, and thus retains the number of active sites for catalytic decomposition of H2O2. Hence, the system containing the as-prepared γ-Fe2O3/C spheres and H2O2 shows the high removal efficiency and degradation efficiency in the remediation of recalcitrant organic contaminants such as methylene blue and sulfamethoxazole.
2020, 31(3): 721-724
doi: 10.1016/j.cclet.2019.09.008
Abstract:
The chiral phosphoric acid catalyzed asymmetric[3 + 2] annulation of substituted 2-vinylindoles with azlactones has been established. This reaction represented a practical approach for the synthesis of structurally diverse pyrrolo[1, 2-a]indoles with two vicinal stereocenters including one tetrasubstituted stereocenter in good yields and good stereoselectivities under mild conditions.
The chiral phosphoric acid catalyzed asymmetric[3 + 2] annulation of substituted 2-vinylindoles with azlactones has been established. This reaction represented a practical approach for the synthesis of structurally diverse pyrrolo[1, 2-a]indoles with two vicinal stereocenters including one tetrasubstituted stereocenter in good yields and good stereoselectivities under mild conditions.
2020, 31(3): 725-728
doi: 10.1016/j.cclet.2019.09.014
Abstract:
The series of salen-bridged bis-pillar[1]arenes were conveniently prepared by condensation reaction of 5, 5'-methylenebis(2-hydroxybenzaldehyde) or 5, 5'-(propane-2, 2-diyl)bis(2-hydroxybenzaldehyde) with mono-amido-functionalized pillar[5]arenes containing different terminal aminoalkyl groups in refluxing ethanol. The 1H NMR and 2D-NOESY spectra indicated that the salen-bridged bis-pillar[5]arenes with longer alkylene linker (n=3, 4, 6) formed the fascinating bis-[1]rotaxanes, while the salenbridged bis-pillar[5]arenes with short hydrazine and ethylenediamino linker (n=0, 2) predominately existed in free form. The single crystal structure of the bis-pillar[5]arene ambiguously indicated that two propylenediamino linker inserted in to two cavities of pillar[5]arene to form a novel bis-[1]rotaxanes.
The series of salen-bridged bis-pillar[1]arenes were conveniently prepared by condensation reaction of 5, 5'-methylenebis(2-hydroxybenzaldehyde) or 5, 5'-(propane-2, 2-diyl)bis(2-hydroxybenzaldehyde) with mono-amido-functionalized pillar[5]arenes containing different terminal aminoalkyl groups in refluxing ethanol. The 1H NMR and 2D-NOESY spectra indicated that the salen-bridged bis-pillar[5]arenes with longer alkylene linker (n=3, 4, 6) formed the fascinating bis-[1]rotaxanes, while the salenbridged bis-pillar[5]arenes with short hydrazine and ethylenediamino linker (n=0, 2) predominately existed in free form. The single crystal structure of the bis-pillar[5]arene ambiguously indicated that two propylenediamino linker inserted in to two cavities of pillar[5]arene to form a novel bis-[1]rotaxanes.
2020, 31(3): 729-732
doi: 10.1016/j.cclet.2019.09.023
Abstract:
A versatile and efficient telescoped reaction sequence for the synthesis of tetrahydroisoquinolines (THIQs) is reported that uses TiCl4 to promote cyclization of a benzylaminoacetal derivative and Et3SiH for reduction of the intermediate 4-hydroxy-THIQ. This method is complimentary to the classical Pomeranz-Fritsch and related reactions since it tolerates electron-withdrawing substituents and allows access to 8-substituted THIQs.
A versatile and efficient telescoped reaction sequence for the synthesis of tetrahydroisoquinolines (THIQs) is reported that uses TiCl4 to promote cyclization of a benzylaminoacetal derivative and Et3SiH for reduction of the intermediate 4-hydroxy-THIQ. This method is complimentary to the classical Pomeranz-Fritsch and related reactions since it tolerates electron-withdrawing substituents and allows access to 8-substituted THIQs.
2020, 31(3): 733-735
doi: 10.1016/j.cclet.2019.09.026
Abstract:
A ferrocene-initiated radical reaction of benzoquinone with amines has been successfully developed for the direct access to diaminobenzoquinone imines in high yields, in which the commercially available and cheap ferrocene was employed as a radical initiator and TBHP was used as an oxidant. Moreover, this reaction could be achieved with low loading of ferrocene (0.5 mol%). This protocol is highly efficient with good substrate tolerance and provides a new approach for the construction of benzoquinone imines with potential pharmaceutical interest.
A ferrocene-initiated radical reaction of benzoquinone with amines has been successfully developed for the direct access to diaminobenzoquinone imines in high yields, in which the commercially available and cheap ferrocene was employed as a radical initiator and TBHP was used as an oxidant. Moreover, this reaction could be achieved with low loading of ferrocene (0.5 mol%). This protocol is highly efficient with good substrate tolerance and provides a new approach for the construction of benzoquinone imines with potential pharmaceutical interest.
2020, 31(3): 736-738
doi: 10.1016/j.cclet.2019.08.010
Abstract:
Herein, the origin of the diastereoselectivity of N-heterocyclic carbene (NHC)-catalyzed cross-benzoin reactions between an α-amino aldehyde and furfural was studied by density functional theory. The computational results showed that the reaction proceeded through four steps:nucleophilic addition of NHC onto furfural, formation of a Breslow intermediate, cross-coupling reaction between Breslow intermediate and α-amino aldehyde, and dissociation of the catalyst. The cross-coupling was identified as the diastereoselectivity-determining step, with the R-configured product generated preferentially. Noncovalent interaction (NCI) analysis showed that the C-H … O and C-H … F interactions were responsible for determining the diastereoselectivity.
Herein, the origin of the diastereoselectivity of N-heterocyclic carbene (NHC)-catalyzed cross-benzoin reactions between an α-amino aldehyde and furfural was studied by density functional theory. The computational results showed that the reaction proceeded through four steps:nucleophilic addition of NHC onto furfural, formation of a Breslow intermediate, cross-coupling reaction between Breslow intermediate and α-amino aldehyde, and dissociation of the catalyst. The cross-coupling was identified as the diastereoselectivity-determining step, with the R-configured product generated preferentially. Noncovalent interaction (NCI) analysis showed that the C-H … O and C-H … F interactions were responsible for determining the diastereoselectivity.
2020, 31(3): 739-745
doi: 10.1016/j.cclet.2019.07.064
Abstract:
A series of novel phenylpyrazole carboxylic acid derivatives containing fluorine moiety, i.e., diamides 11, simple aryl-bearing amides 12 and acylthioureas 14 were successfully synthesized based on the key fluoro-containing phenylpyrazole acid intermediate. The new compounds were identified and confirmed by melting point, 1H NMR, 13C NMR and elemental analysis or HRMS. The bioassay results indicated that some of the compounds possessed excellent insecticidal activities towards oriental armyworm, diamondback moth and corn borer at low concentrations. For examples, compounds 11a, 11e-g and 14b exhibited remarkable larvicidal activities with LC50 values of 0.13-0.39 mg/L and 0.0002-0.0014 mg/L against oriental armyworm and diamondback moth, respectively, were comparable with those of the control chlorantraniliprole. Particularly, 11e were found superior to chlorantraniliprole in oriental armyworm tests (LC50:0.23 mg/L vs. 0.26 mg/L); 11a, 11e, 11f and 14c in diamondback moth tests with LC50 values of 0.0002 mg/L, 0.0002 mg/L, 0.0008 mg/L and 0.0005 mg/L, respectively, were more effective than that of chlorantraniliprole. In addition, 12a also showed a promising insecticidal potential and development/optimization advantage. Compounds 11a, 11e-g, 12a, 14b and 14c could be considered as possible new leading structures for further study. The SAR investigation indicated that the compounds with fluorine motif (e.g., -F, -CF2H, -CF3) held apparently favorable insecticidal potentials, which provided useful guidance for further design/development of new phenylpyrazole-containing agrochemicals.
A series of novel phenylpyrazole carboxylic acid derivatives containing fluorine moiety, i.e., diamides 11, simple aryl-bearing amides 12 and acylthioureas 14 were successfully synthesized based on the key fluoro-containing phenylpyrazole acid intermediate. The new compounds were identified and confirmed by melting point, 1H NMR, 13C NMR and elemental analysis or HRMS. The bioassay results indicated that some of the compounds possessed excellent insecticidal activities towards oriental armyworm, diamondback moth and corn borer at low concentrations. For examples, compounds 11a, 11e-g and 14b exhibited remarkable larvicidal activities with LC50 values of 0.13-0.39 mg/L and 0.0002-0.0014 mg/L against oriental armyworm and diamondback moth, respectively, were comparable with those of the control chlorantraniliprole. Particularly, 11e were found superior to chlorantraniliprole in oriental armyworm tests (LC50:0.23 mg/L vs. 0.26 mg/L); 11a, 11e, 11f and 14c in diamondback moth tests with LC50 values of 0.0002 mg/L, 0.0002 mg/L, 0.0008 mg/L and 0.0005 mg/L, respectively, were more effective than that of chlorantraniliprole. In addition, 12a also showed a promising insecticidal potential and development/optimization advantage. Compounds 11a, 11e-g, 12a, 14b and 14c could be considered as possible new leading structures for further study. The SAR investigation indicated that the compounds with fluorine motif (e.g., -F, -CF2H, -CF3) held apparently favorable insecticidal potentials, which provided useful guidance for further design/development of new phenylpyrazole-containing agrochemicals.
2020, 31(3): 746-750
doi: 10.1016/j.cclet.2019.08.030
Abstract:
In this paper, norbornene imidazolium hexafluorophosphate (NM-MIm-PF6) was modified on the surface of aminopropyl silica by ring-opening metathesis polymerization (ROMP), and then oligo(ethylene glycol) methacrylate (OEGMA) were grafted on the surface by atom transfer radical polymerization (ATRP). Some characterizations in this article confirmed that the synthesis of P(NM-MIm-PF6)-SiPOEGMA (P1-Si-P2) is successful. The P1-Si-P2 can separate sugars, amino acids, sulfonamides in a hydrophilic interaction mode and alkyl benzene, polycyclic aromatic hydrocarbon in a reverse phase mode. The experiment also found that the column has typical characteristics of hydrophobic/hydrophilic separation mechanism. Compared to single hydrophobic C18 column and single hydrophilic Si-NH2 column, this P1-Si-P2 shows certain advantages.
In this paper, norbornene imidazolium hexafluorophosphate (NM-MIm-PF6) was modified on the surface of aminopropyl silica by ring-opening metathesis polymerization (ROMP), and then oligo(ethylene glycol) methacrylate (OEGMA) were grafted on the surface by atom transfer radical polymerization (ATRP). Some characterizations in this article confirmed that the synthesis of P(NM-MIm-PF6)-SiPOEGMA (P1-Si-P2) is successful. The P1-Si-P2 can separate sugars, amino acids, sulfonamides in a hydrophilic interaction mode and alkyl benzene, polycyclic aromatic hydrocarbon in a reverse phase mode. The experiment also found that the column has typical characteristics of hydrophobic/hydrophilic separation mechanism. Compared to single hydrophobic C18 column and single hydrophilic Si-NH2 column, this P1-Si-P2 shows certain advantages.
2020, 31(3): 751-754
doi: 10.1016/j.cclet.2019.09.033
Abstract:
It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates. In this study, we developed a facile method to induce the La doping and cationic vacancie (VZn) on ZnO for the highly efficient complete NO oxidation. The photocatalytic NO removal efficiency increases from 36.2% to 53.6%. Most importantly, a significant suppressed NO2 production also has been realized. According to the DFTcalculations, ESR spectra and in situ FTIR spectra, the introduction of La3+ induce the redistribution of charge carriers in La-ZnO, which promote the production of·O2- and lead to the formation of VZn for the formation of·OH, contributing to the complete oxidation of NO to nitrate. Besides, the conversion pathway of photocatalytic NO oxidation has been elaborated. This work paves a new way to simultaneously realize the photocatalytic pollutants removal and the inhibition of toxic intermediates generation for efficient and safe air purification.
It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates. In this study, we developed a facile method to induce the La doping and cationic vacancie (VZn) on ZnO for the highly efficient complete NO oxidation. The photocatalytic NO removal efficiency increases from 36.2% to 53.6%. Most importantly, a significant suppressed NO2 production also has been realized. According to the DFTcalculations, ESR spectra and in situ FTIR spectra, the introduction of La3+ induce the redistribution of charge carriers in La-ZnO, which promote the production of·O2- and lead to the formation of VZn for the formation of·OH, contributing to the complete oxidation of NO to nitrate. Besides, the conversion pathway of photocatalytic NO oxidation has been elaborated. This work paves a new way to simultaneously realize the photocatalytic pollutants removal and the inhibition of toxic intermediates generation for efficient and safe air purification.
2020, 31(3): 755-758
doi: 10.1016/j.cclet.2019.09.019
Abstract:
Fluorescence switch plays a vital role in bioelectronics and bioimaging. Herein, we presented a new kind of facile electrostatic complex nanoparticles (ECNs) for fluorescence switching in cells and marking of individual cell. The ECNs were prepared by mixing positively charged poly(6-(2-(thiophen-3-yl)ethoxy) hexyl trimethylammonium bromide) (PT) and negatively charged diarylethene sodium salt (DAECOONa). DAE-COONa is a photoswitchable molecule which can be transformed between the ring-closed form and ring-open form under the irradiation of UV or visible light. The closed-form of DAE-COONa can efficiently quench the fluorescence of PT through intermolecular energy transfer, while the open form of DAE-COONa does not influence the emission of PT. Thus, the fluorescence of ECNs can be modulated by light irradiation, and the ECNs with good fluorescence switching performance have been employed for fluorescence imaging and individual cell lighting up process successfully. We demonstrate that the electrostatic complex strategy provides a facile method to construct fluorescence switch for selective cell marking and imaging applications.
Fluorescence switch plays a vital role in bioelectronics and bioimaging. Herein, we presented a new kind of facile electrostatic complex nanoparticles (ECNs) for fluorescence switching in cells and marking of individual cell. The ECNs were prepared by mixing positively charged poly(6-(2-(thiophen-3-yl)ethoxy) hexyl trimethylammonium bromide) (PT) and negatively charged diarylethene sodium salt (DAECOONa). DAE-COONa is a photoswitchable molecule which can be transformed between the ring-closed form and ring-open form under the irradiation of UV or visible light. The closed-form of DAE-COONa can efficiently quench the fluorescence of PT through intermolecular energy transfer, while the open form of DAE-COONa does not influence the emission of PT. Thus, the fluorescence of ECNs can be modulated by light irradiation, and the ECNs with good fluorescence switching performance have been employed for fluorescence imaging and individual cell lighting up process successfully. We demonstrate that the electrostatic complex strategy provides a facile method to construct fluorescence switch for selective cell marking and imaging applications.
2020, 31(3): 759-763
doi: 10.1016/j.cclet.2019.09.021
Abstract:
Direct, in situ selective detection of intracellular formaldehyde (FA) is of great significance for understanding its function in FA-related diseases. Herein, red carbon dots (RCD) are reported as label-free two-photon fluorescent nanoprobes for detecting and imaging of FA. Upon addition of FA, the -NH2 groups of RCD could quickly and specially react with aldehydes to form Schiff base and then the strong fluorescence of RCD with blue-shift emission is recovery due to the destruction of the hydrogen bond interaction between RCD and water. In addition, the nanoprobes exhibit outstanding photostability, rapid response (< 1 min), high sensitivity (~9.9 μmol/L) and excellent selectivity toward FA over other aldehyde group compounds. Notably, owing to the good cell-membrane permeability and biocompatibility, as well as the large two-photon absorption cross-section, the as-prepared RCD can be used as label-free nanoprobes for selectively detecting and imaging FA in living cells and zebrafishes through one-photon and two-photon excitation. Moreover, RCD could stain the tissue of zebrafishes at depths interval of up to 240 mm under two-photon excitation. This research implied that RCD are promising tools for directly and in situ imaging FA in vivo, thus providing critical insights into FA-related pathophysiological processes.
Direct, in situ selective detection of intracellular formaldehyde (FA) is of great significance for understanding its function in FA-related diseases. Herein, red carbon dots (RCD) are reported as label-free two-photon fluorescent nanoprobes for detecting and imaging of FA. Upon addition of FA, the -NH2 groups of RCD could quickly and specially react with aldehydes to form Schiff base and then the strong fluorescence of RCD with blue-shift emission is recovery due to the destruction of the hydrogen bond interaction between RCD and water. In addition, the nanoprobes exhibit outstanding photostability, rapid response (< 1 min), high sensitivity (~9.9 μmol/L) and excellent selectivity toward FA over other aldehyde group compounds. Notably, owing to the good cell-membrane permeability and biocompatibility, as well as the large two-photon absorption cross-section, the as-prepared RCD can be used as label-free nanoprobes for selectively detecting and imaging FA in living cells and zebrafishes through one-photon and two-photon excitation. Moreover, RCD could stain the tissue of zebrafishes at depths interval of up to 240 mm under two-photon excitation. This research implied that RCD are promising tools for directly and in situ imaging FA in vivo, thus providing critical insights into FA-related pathophysiological processes.
2020, 31(3): 764-768
doi: 10.1016/j.cclet.2019.11.020
Abstract:
Two series of sulfur-containing diarylbenzopyrimidines are designed by the fragment combination of a thioacetamide with our previous disclosed DABP 3 and further oxidation. The best compound 6e with a sulfonyl scaffold displayed EC50 values of 0.0356 μmol/L against WT and 0.0228 μmol/L against HIV K103N mutant strain. More pronounced, it had a lower cytotoxicity (CC50=99.6 μmol/L), higher selectivity index (SIWT=2799, SIK103N=4375) and better calculated logarithm of the octanol-water partition coefficient (cLogP) than the lead compound 3. Molecular docking and dynamics provided the binding modes of these compounds with reverse transcriptase, explaining their activity. Collectively, the new compounds could be candidates for anti-HIV drug discovery.
Two series of sulfur-containing diarylbenzopyrimidines are designed by the fragment combination of a thioacetamide with our previous disclosed DABP 3 and further oxidation. The best compound 6e with a sulfonyl scaffold displayed EC50 values of 0.0356 μmol/L against WT and 0.0228 μmol/L against HIV K103N mutant strain. More pronounced, it had a lower cytotoxicity (CC50=99.6 μmol/L), higher selectivity index (SIWT=2799, SIK103N=4375) and better calculated logarithm of the octanol-water partition coefficient (cLogP) than the lead compound 3. Molecular docking and dynamics provided the binding modes of these compounds with reverse transcriptase, explaining their activity. Collectively, the new compounds could be candidates for anti-HIV drug discovery.
2020, 31(3): 769-773
doi: 10.1016/j.cclet.2020.01.007
Abstract:
Carbon dots have unique advantages in biological applications owing to their excellent optical properties. However, the biosafety evaluation of carbon dots has limitations owing to cytotoxicity in vitro, and there is little pre-safety evaluation before in vivo and clinical applications. Whether the carbon dots are or not suitable for applications in vivo, evaluation analysis can be made based on hemolysis and changes in erythrocyte morphology. In this work, a green fluorescent N, S-doped carbon dots (N, S-CDs) were obtained by hydrothermal method, tobias acid, and m-phenylenediamine as precursors. N, S-CDs not only possessed excellent dispersibility, uniform particle size, high quantum yield (37.2%) and stable photoluminescence property but also retain their photostability and strong fluorescence intensity in the acid/alkaline solutions, different ionic strengths (NaCl) and under 365 nm UV illumination. Moreover, the N, S-CDs displayed low cytotoxicity and high cellular uptake efficiency in human umbilical vein endothelial cells (HUVEC) and excellent blood compatibility to the erythrocyte. It is foreseeable that N, S-CDs could be further studied as a promising biological imaging agent in vivo.
Carbon dots have unique advantages in biological applications owing to their excellent optical properties. However, the biosafety evaluation of carbon dots has limitations owing to cytotoxicity in vitro, and there is little pre-safety evaluation before in vivo and clinical applications. Whether the carbon dots are or not suitable for applications in vivo, evaluation analysis can be made based on hemolysis and changes in erythrocyte morphology. In this work, a green fluorescent N, S-doped carbon dots (N, S-CDs) were obtained by hydrothermal method, tobias acid, and m-phenylenediamine as precursors. N, S-CDs not only possessed excellent dispersibility, uniform particle size, high quantum yield (37.2%) and stable photoluminescence property but also retain their photostability and strong fluorescence intensity in the acid/alkaline solutions, different ionic strengths (NaCl) and under 365 nm UV illumination. Moreover, the N, S-CDs displayed low cytotoxicity and high cellular uptake efficiency in human umbilical vein endothelial cells (HUVEC) and excellent blood compatibility to the erythrocyte. It is foreseeable that N, S-CDs could be further studied as a promising biological imaging agent in vivo.
2020, 31(3): 774-778
doi: 10.1016/j.cclet.2019.09.016
Abstract:
Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science. Especially, it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors. Herein, we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes (Co3O4/NCNTs) hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air. The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2 reduction in neutral solutions and glucose oxidation in alkaline solutions. As sensor electrode, the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2 response with a sensitivity of 87.40 μA (mmol/L)-1 cm-2, a linear range of 5.00 μmol/L-11.00 mmol/L, and a detection limitation of 1 μmol/L in H2O2 detection, and a good glucose detection performance with 5 μmol/L. These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.
Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science. Especially, it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors. Herein, we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes (Co3O4/NCNTs) hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air. The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2 reduction in neutral solutions and glucose oxidation in alkaline solutions. As sensor electrode, the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2 response with a sensitivity of 87.40 μA (mmol/L)-1 cm-2, a linear range of 5.00 μmol/L-11.00 mmol/L, and a detection limitation of 1 μmol/L in H2O2 detection, and a good glucose detection performance with 5 μmol/L. These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.
2020, 31(3): 779-782
doi: 10.1016/j.cclet.2019.05.015
Abstract:
Considering the importance and complexity of benzene oxidation on mineral oxide aerosol surfaces in the atmosphere, gas-phase 3d-transition metal oxide cations were used as models of active sites on mineral oxide aerosols to mimic the corresponding reactions. The various cations have been prepared by laser ablation and reacted with benzene in a linear ion trap reactor. Of the 103 systematically investigated cations, 39 clusters can oxidize benzene at room temperature. In addition to the adsorption channel, other five types of reaction channels were observed, including dehydrogenation of C6H6, charge exchange, hydrogen atom transfer, oxygen atom transfer, and the formation of C6H5O·radical, among which the first two pathways are prevalent and the formation of C6H6O+ cations has not been reported in literature. The insight into the benzene oxidation reactions derived from the gas-phase model systems is helpful to build a detailed picture of oxidative mechanisms of C6H6 and its derivatives over corresponding mineral oxide aerosols.
Considering the importance and complexity of benzene oxidation on mineral oxide aerosol surfaces in the atmosphere, gas-phase 3d-transition metal oxide cations were used as models of active sites on mineral oxide aerosols to mimic the corresponding reactions. The various cations have been prepared by laser ablation and reacted with benzene in a linear ion trap reactor. Of the 103 systematically investigated cations, 39 clusters can oxidize benzene at room temperature. In addition to the adsorption channel, other five types of reaction channels were observed, including dehydrogenation of C6H6, charge exchange, hydrogen atom transfer, oxygen atom transfer, and the formation of C6H5O·radical, among which the first two pathways are prevalent and the formation of C6H6O+ cations has not been reported in literature. The insight into the benzene oxidation reactions derived from the gas-phase model systems is helpful to build a detailed picture of oxidative mechanisms of C6H6 and its derivatives over corresponding mineral oxide aerosols.
2020, 31(3): 783-786
doi: 10.1016/j.cclet.2019.05.021
Abstract:
In this paper we report the desgin and synthesis of dihydroxyindoles oligomers based reversible fluorescence sensor. We find dihydroxyindoles-2-carboxylic acid derived oligmer (P-DHICA) has the highest selectivity and sensitivity for Cu2+ detection. This work provide a highly efficient, environmentally friendly biosensor for potential use in medical testing.
In this paper we report the desgin and synthesis of dihydroxyindoles oligomers based reversible fluorescence sensor. We find dihydroxyindoles-2-carboxylic acid derived oligmer (P-DHICA) has the highest selectivity and sensitivity for Cu2+ detection. This work provide a highly efficient, environmentally friendly biosensor for potential use in medical testing.
2020, 31(3): 787-791
doi: 10.1016/j.cclet.2019.05.025
Abstract:
A novel near-infrared light photothemal-activated H2S-donating nanocomposite hydrogel was developed, through combination of a thermo-labile H2S donor and photothermal nanoparticles in agarose hydrogel. The polyethylenimine dithiocarbamate polymer, a thermo-labile compound, was synthesized as a novel H2S donor. The combination of a thermo-labile hydrogen sulfide donor and photothermal nanoparticles enabled the generation of H2S in agarose hydrogel upon irradiation with near-infrared light. The ability to modulate the photoirradiation for controlled generation and spatiotemporally release of H2S are its specific advantages. This photothermal spatiotemporally controlled H2S-releasing strategy was successfully applied to anti-inflammation treatment in a rat model, demonstrating its utility as a novel H2S-based therapeutic approach.
A novel near-infrared light photothemal-activated H2S-donating nanocomposite hydrogel was developed, through combination of a thermo-labile H2S donor and photothermal nanoparticles in agarose hydrogel. The polyethylenimine dithiocarbamate polymer, a thermo-labile compound, was synthesized as a novel H2S donor. The combination of a thermo-labile hydrogen sulfide donor and photothermal nanoparticles enabled the generation of H2S in agarose hydrogel upon irradiation with near-infrared light. The ability to modulate the photoirradiation for controlled generation and spatiotemporally release of H2S are its specific advantages. This photothermal spatiotemporally controlled H2S-releasing strategy was successfully applied to anti-inflammation treatment in a rat model, demonstrating its utility as a novel H2S-based therapeutic approach.
2020, 31(3): 792-796
doi: 10.1016/j.cclet.2019.05.030
Abstract:
Nitrogen photofixation using g-C3N4-based photocatalysts have attracted abundant of attentions recently. Herein, in this study, holey g-C3N4 (HGCN) nanosheets possess a good deal of carbon vacancies were prepared by means of thermally treating bulk g-C3N4 (BGCN) under an NH3 atmosphere. Characterization analysis revealed that the as-synthesized sample have identical crystal structure, larger BET specific surface area, stronger reduction capability, and higher photogenerated charge carrier separation rate than that of BGCN. These properties may contribute to enhance the nitrogen photofixation activity. It was also found that the rate of NH4+ production for N2 photofixation of HGCN sample reached~25.54 mg L-1 h-1 gcat-1, which is approximately~5.87 times higher than that of BGCN sample under optimal reactive conditions. Moreover, a plausible mechanism of HGCN for nitrogen photofixation process was illuminated in detail.
Nitrogen photofixation using g-C3N4-based photocatalysts have attracted abundant of attentions recently. Herein, in this study, holey g-C3N4 (HGCN) nanosheets possess a good deal of carbon vacancies were prepared by means of thermally treating bulk g-C3N4 (BGCN) under an NH3 atmosphere. Characterization analysis revealed that the as-synthesized sample have identical crystal structure, larger BET specific surface area, stronger reduction capability, and higher photogenerated charge carrier separation rate than that of BGCN. These properties may contribute to enhance the nitrogen photofixation activity. It was also found that the rate of NH4+ production for N2 photofixation of HGCN sample reached~25.54 mg L-1 h-1 gcat-1, which is approximately~5.87 times higher than that of BGCN sample under optimal reactive conditions. Moreover, a plausible mechanism of HGCN for nitrogen photofixation process was illuminated in detail.
2020, 31(3): 797-800
doi: 10.1016/j.cclet.2019.05.024
Abstract:
Electronic polarization has an important impact on the site energies of charge carriers that play a key role in determining the charge transport in organic semiconductors. Dipolar molecules have strong intermolecular interactions and widespread applications in organic optoelectronics. However, compared with nonpolar organic semiconductors, electronic polarization for dipolar systems has been rarely studied. Here, taking 1, 2, 3, 4-tetrafluoro-6, 7-dimethylnaphthalene as representative, we have calculated the electronic polarization energies of dipolar organic molecular crystals by means of a polarizable forcefield method. Surprisingly, our results point to that the polarization energies for this dipolar system are similar to those of nonpolar systems. In addition, the π-π stack contributes only about 30%~40% to the total polarization energy, thus the polarization effects along the three dimensions should be treated equally even for the one-dimensional stacking crystals.
Electronic polarization has an important impact on the site energies of charge carriers that play a key role in determining the charge transport in organic semiconductors. Dipolar molecules have strong intermolecular interactions and widespread applications in organic optoelectronics. However, compared with nonpolar organic semiconductors, electronic polarization for dipolar systems has been rarely studied. Here, taking 1, 2, 3, 4-tetrafluoro-6, 7-dimethylnaphthalene as representative, we have calculated the electronic polarization energies of dipolar organic molecular crystals by means of a polarizable forcefield method. Surprisingly, our results point to that the polarization energies for this dipolar system are similar to those of nonpolar systems. In addition, the π-π stack contributes only about 30%~40% to the total polarization energy, thus the polarization effects along the three dimensions should be treated equally even for the one-dimensional stacking crystals.
2020, 31(3): 801-804
doi: 10.1016/j.cclet.2019.05.028
Abstract:
The temperature-dependent structural changes in 1-butyl-3-methylimidazolium tetrafluoride ([Bmim]FeCl4) magnetic ionic liquid (MIL) were investigated by using in-situ X-ray absorption fine structure (XAFS) combined with Raman spectroscopy and DFTcalculations. XAFS results revealed that the coordination number and bond length of Fe-Cl in the anion of[Bmim]FeCl4 MIL decreased with increments in temperature. These results directly reflected the dissociation of tetrahedral structure[FeCl4]-, and the formation of bridge-chain[Fe2Cl5]+, and[FeCl2]+ species in the anion of[Bmim]FeCl4 MIL. These behaviors indicated that[FeCl4]- dissociation was endothermic, and was promoted by increased temperature. The results obtained through XAFS were in agreement with those obtained through Raman spectroscopy and DFT calculations.
The temperature-dependent structural changes in 1-butyl-3-methylimidazolium tetrafluoride ([Bmim]FeCl4) magnetic ionic liquid (MIL) were investigated by using in-situ X-ray absorption fine structure (XAFS) combined with Raman spectroscopy and DFTcalculations. XAFS results revealed that the coordination number and bond length of Fe-Cl in the anion of[Bmim]FeCl4 MIL decreased with increments in temperature. These results directly reflected the dissociation of tetrahedral structure[FeCl4]-, and the formation of bridge-chain[Fe2Cl5]+, and[FeCl2]+ species in the anion of[Bmim]FeCl4 MIL. These behaviors indicated that[FeCl4]- dissociation was endothermic, and was promoted by increased temperature. The results obtained through XAFS were in agreement with those obtained through Raman spectroscopy and DFT calculations.
2020, 31(3): 805-808
doi: 10.1016/j.cclet.2019.05.045
Abstract:
A promising biomass carbon material, manufactured by the carbonation of Physalis peruviana L. calyx at 700 ℃, is presented in this work. Morphology characterization shows that the carbon material possesses long microtubule bundling and above 30% natural O-atom component on the surface. After KOH chemical etching, the materials maintain the oxygen content but exhibit more micropores and higher specific surface area up to 1732.6 m2/g. Using as an electrode material for supercapacitor, the active carbon material exhibits high specific capacitance up to 339.7 F/g at 0.5 A/g in 3 mol/L KOH aqueous solution through three-electrode system. The active carbon material also exhibits excellent cycling stability (97% retention) by 10, 000 cycles at 10 A/g. The outstanding electrochemical performances are attributing to the unique long microtubule bundling with much more pores and the abundant O element on the surface. This biomass carbon material with excellent electrochemical properties could be a useful material for multiple applications.
A promising biomass carbon material, manufactured by the carbonation of Physalis peruviana L. calyx at 700 ℃, is presented in this work. Morphology characterization shows that the carbon material possesses long microtubule bundling and above 30% natural O-atom component on the surface. After KOH chemical etching, the materials maintain the oxygen content but exhibit more micropores and higher specific surface area up to 1732.6 m2/g. Using as an electrode material for supercapacitor, the active carbon material exhibits high specific capacitance up to 339.7 F/g at 0.5 A/g in 3 mol/L KOH aqueous solution through three-electrode system. The active carbon material also exhibits excellent cycling stability (97% retention) by 10, 000 cycles at 10 A/g. The outstanding electrochemical performances are attributing to the unique long microtubule bundling with much more pores and the abundant O element on the surface. This biomass carbon material with excellent electrochemical properties could be a useful material for multiple applications.
2020, 31(3): 809-812
doi: 10.1016/j.cclet.2019.05.050
Abstract:
A nonanuclear Cu4ⅡTi5Ⅳ heterometallic cluster, [Ti5Cu4O6(ba)16] (1, Hba=benzoic acid) was synthesized in one-pot reaction under the solvothermal condition. The metallic skeleton 1 contains a Ti5 core constructed from two vertex-shared Ti3 triangles and four separated Cu atoms outside which are connected together by μ3-O2- ions. Total 16 ba- ligands adopt μ2-η1:η1 coordination mode to protect the overall heterometallic core. Due to the unique d-d transitions of CuⅡ ion, the reflectance spectrum of 1 displays broad and strong absorption towards visible light extending to the near-infrared region. Moreover, 1 shows almost purely paramagnetic behavior with the presence of weak antiferromagnetic interactions at low temperatures.
A nonanuclear Cu4ⅡTi5Ⅳ heterometallic cluster, [Ti5Cu4O6(ba)16] (1, Hba=benzoic acid) was synthesized in one-pot reaction under the solvothermal condition. The metallic skeleton 1 contains a Ti5 core constructed from two vertex-shared Ti3 triangles and four separated Cu atoms outside which are connected together by μ3-O2- ions. Total 16 ba- ligands adopt μ2-η1:η1 coordination mode to protect the overall heterometallic core. Due to the unique d-d transitions of CuⅡ ion, the reflectance spectrum of 1 displays broad and strong absorption towards visible light extending to the near-infrared region. Moreover, 1 shows almost purely paramagnetic behavior with the presence of weak antiferromagnetic interactions at low temperatures.
2020, 31(3): 813-817
doi: 10.1016/j.cclet.2019.05.055
Abstract:
A metal-organic framework, Ce-FDM-50, was constructed by employing gallic acid featuring both carboxylate and pyrogallate as the coordinating sites and Ce(Ⅲ). The co-assembly of the carboxylates and pyrogallates with two metal ions have achieved a new type of paddle wheel secondary building unit. These building units were further joined by organic struts to obtain frameworks in sql topology. This synthetic approach could be expanded to five different lanthanide metals (Nd, Eu, Gd, Tb, Yb) for the construction of a series of isoreticular MOFs based on FDM-50, and even MTV-MOFs in which mixed lanthanide metals with specific ratios were distributed. In addition, featuring the lanthanide metals as the inorganic nodes in the network, Tb-FDM-50 showed distinct luminescence properties that could be furtherly tuned for variable applications.
A metal-organic framework, Ce-FDM-50, was constructed by employing gallic acid featuring both carboxylate and pyrogallate as the coordinating sites and Ce(Ⅲ). The co-assembly of the carboxylates and pyrogallates with two metal ions have achieved a new type of paddle wheel secondary building unit. These building units were further joined by organic struts to obtain frameworks in sql topology. This synthetic approach could be expanded to five different lanthanide metals (Nd, Eu, Gd, Tb, Yb) for the construction of a series of isoreticular MOFs based on FDM-50, and even MTV-MOFs in which mixed lanthanide metals with specific ratios were distributed. In addition, featuring the lanthanide metals as the inorganic nodes in the network, Tb-FDM-50 showed distinct luminescence properties that could be furtherly tuned for variable applications.
2020, 31(3): 818-820
doi: 10.1016/j.cclet.2019.06.047
Abstract:
In this study, we report the synthesis of novel palladium nanoflowers (Pd NFs) on amino-functionalized fullerene (C60-NH2) by hydrothermal self-assembly growth using ethylenediamine (EA) as a functional reagent. The successful formation of Pd nanoflowers supported amino-functionalized fullerene (C60-NH2/Pd NFs) is evidenced by UV-vis and powder X-ray diffraction (XRD). The morphology of Pd NFs over the C60-NH2 surface has been investigated by high-resolution transmission electron microscopy (TEM) and Fourier-transform infrared (FT-IR) techniques. The supported Pd nanoflowers (Pd NFs/C60-NH2) exhibit remarkably superior catalytic activity toward the reduction of 4-nitrophenol (4-NP). It exhibits remarkable UV-vis spectra response from 4-nitrophenol to 4-aminophenol (4-AP) (99% in 2.0 min) with a turnover frequency of 12.35 min-1. Its excellent catalytic stability and durability offer the promising application in catalysis.
In this study, we report the synthesis of novel palladium nanoflowers (Pd NFs) on amino-functionalized fullerene (C60-NH2) by hydrothermal self-assembly growth using ethylenediamine (EA) as a functional reagent. The successful formation of Pd nanoflowers supported amino-functionalized fullerene (C60-NH2/Pd NFs) is evidenced by UV-vis and powder X-ray diffraction (XRD). The morphology of Pd NFs over the C60-NH2 surface has been investigated by high-resolution transmission electron microscopy (TEM) and Fourier-transform infrared (FT-IR) techniques. The supported Pd nanoflowers (Pd NFs/C60-NH2) exhibit remarkably superior catalytic activity toward the reduction of 4-nitrophenol (4-NP). It exhibits remarkable UV-vis spectra response from 4-nitrophenol to 4-aminophenol (4-AP) (99% in 2.0 min) with a turnover frequency of 12.35 min-1. Its excellent catalytic stability and durability offer the promising application in catalysis.
2020, 31(3): 821-825
doi: 10.1016/j.cclet.2019.05.018
Abstract:
Existing grasping technologies have persistent challenges with unstructured objects and environments, highlighting an increasing demand for methods that conform to various application scenarios. Inspired by the chameleon tongue, a soft-contact grasping manipulator empowered by a class of adhesive gels has been demonstrated. The adhesives enable the manipulator to rapidly and strongly adhere to diverse substrates with varied surfaces, shapes and sizes, also to release objects under mild conditions. The robustness of such adhesive gels was highlighted with the remarkable recyclability, broad temperature tolerance and long-term stability. Furthermore, a general approach was developed to reconcile the contradiction of simultaneously enhancing their interfacial adhesion and cohesion strength that exists in conventional glues. We anticipate that this work will offer a strategy of developing adhesive materials and pave the way towards new applications of soft materials in the emerging fields of soft robotic devices and smart manufacturing.
Existing grasping technologies have persistent challenges with unstructured objects and environments, highlighting an increasing demand for methods that conform to various application scenarios. Inspired by the chameleon tongue, a soft-contact grasping manipulator empowered by a class of adhesive gels has been demonstrated. The adhesives enable the manipulator to rapidly and strongly adhere to diverse substrates with varied surfaces, shapes and sizes, also to release objects under mild conditions. The robustness of such adhesive gels was highlighted with the remarkable recyclability, broad temperature tolerance and long-term stability. Furthermore, a general approach was developed to reconcile the contradiction of simultaneously enhancing their interfacial adhesion and cohesion strength that exists in conventional glues. We anticipate that this work will offer a strategy of developing adhesive materials and pave the way towards new applications of soft materials in the emerging fields of soft robotic devices and smart manufacturing.
2020, 31(3): 826-830
doi: 10.1016/j.cclet.2019.06.003
Abstract:
Recent development of self-healing material has attracted tremendous attention, owing to its biomimetic ability to restore structure and functionality when encountering damages. Here, we develop a threedimensional (3D) printable self-healing composite conductive polymer by mixing hydrogen-bond-based supramolecular polymer with low-cost carbon black. It has a room-temperature self-healing capability in both conductivity and mechanical property, while its shear-thinning behavior enables fabrication of a self-healable circuit by 3D printing technology. As an application, the circuit shows an excellent temperature-dependent behavior of the resistance, indicating its great potential for practical application in the artificial intelligence field.
Recent development of self-healing material has attracted tremendous attention, owing to its biomimetic ability to restore structure and functionality when encountering damages. Here, we develop a threedimensional (3D) printable self-healing composite conductive polymer by mixing hydrogen-bond-based supramolecular polymer with low-cost carbon black. It has a room-temperature self-healing capability in both conductivity and mechanical property, while its shear-thinning behavior enables fabrication of a self-healable circuit by 3D printing technology. As an application, the circuit shows an excellent temperature-dependent behavior of the resistance, indicating its great potential for practical application in the artificial intelligence field.
2020, 31(3): 831-835
doi: 10.1016/j.cclet.2019.06.009
Abstract:
Polymer electrolytes are essential for next-generation lithium batteries because of their excellent safety record. However, low ionic conductivity is the main obstacle restricting their commercial application. Composites with nanoparticles are a promising route to overcome this obstacle. In this work, lithium polystyrene sulfonate brushes (LiPSS) is anchored to silicon dioxide nanoparticles with chemical bonding using atom transfer radial polymerization (SI-ATRP). The composite polymer electrolytes are made by mixing vinylene carbonate and nanoparticles via a facile in situ polymerization process. The ionic conductivity of composite polymer electrolytes is improved to 7.2 ×10-4 S/cm at room temperature, which is attributed to the low degree of crystallinity of polymer electrolyte and the fast ion transport on the surfaces of polymer brush layers that act as a conductive network. The composite polymer electrolytes show a wide electrochemical window of approximately 4.5 V vs. Li+/Li and excellent cycling performance retention of approximately 95% after 100 cycles at ambient temperature. The results also prove that surface groups of ceramic nanoparticles are an important way to increase the electrochemical properties of composite polymer electrolytes.
Polymer electrolytes are essential for next-generation lithium batteries because of their excellent safety record. However, low ionic conductivity is the main obstacle restricting their commercial application. Composites with nanoparticles are a promising route to overcome this obstacle. In this work, lithium polystyrene sulfonate brushes (LiPSS) is anchored to silicon dioxide nanoparticles with chemical bonding using atom transfer radial polymerization (SI-ATRP). The composite polymer electrolytes are made by mixing vinylene carbonate and nanoparticles via a facile in situ polymerization process. The ionic conductivity of composite polymer electrolytes is improved to 7.2 ×10-4 S/cm at room temperature, which is attributed to the low degree of crystallinity of polymer electrolyte and the fast ion transport on the surfaces of polymer brush layers that act as a conductive network. The composite polymer electrolytes show a wide electrochemical window of approximately 4.5 V vs. Li+/Li and excellent cycling performance retention of approximately 95% after 100 cycles at ambient temperature. The results also prove that surface groups of ceramic nanoparticles are an important way to increase the electrochemical properties of composite polymer electrolytes.
2020, 31(3): 836-840
doi: 10.1016/j.cclet.2019.06.018
Abstract:
Deposition of platinum (Pt) monolayers (PtML) on Au substrate represents a robust strategy to maximally utilize the Pt atoms and meanwhile achieve high catalytic activity towards methanol oxidation reaction for direct methanol fuel cells owing to a substrate-induced tensile strain effect. However, recent studies showed that PtML on Au substrate are far from perfect smooth monoatomic layer, but actually exhibited three-dimensional nanoclusters. Moreover, the PtML suffered from severe structural instability and thus activity degradation during long-term electrocatalysis. To regulate the growth of PtML on Au surface and also to improve its structural stability, we exploit dealloyed AuCu core-shell nanoparticles as a new substrate for depositing PtML. By using high-resolution scanning transmission electron microscopy and energy dispersive X-ray elemental mapping combined with electrochemical characterizations, we reveal that the dealloyed AuCu core-shell nanoparticles can effectively promote the deposition of PtML closer to a smooth monolayer structure, thus leading to a higher utilization efficiency of Pt and higher intrinsic activity towards methanol oxidation compared to those on pure Au nanoparticles. Moreover, the PtML deposited on the AuCu core-shell NPs showed substantially enhanced stability compared to those on pure Au NPs during long-term electrocatalysis over several hours, during which segregation of Cu to the Au/Pt interface was revealed and suggested to play an important role in stabilizing the PtML catalysts.
Deposition of platinum (Pt) monolayers (PtML) on Au substrate represents a robust strategy to maximally utilize the Pt atoms and meanwhile achieve high catalytic activity towards methanol oxidation reaction for direct methanol fuel cells owing to a substrate-induced tensile strain effect. However, recent studies showed that PtML on Au substrate are far from perfect smooth monoatomic layer, but actually exhibited three-dimensional nanoclusters. Moreover, the PtML suffered from severe structural instability and thus activity degradation during long-term electrocatalysis. To regulate the growth of PtML on Au surface and also to improve its structural stability, we exploit dealloyed AuCu core-shell nanoparticles as a new substrate for depositing PtML. By using high-resolution scanning transmission electron microscopy and energy dispersive X-ray elemental mapping combined with electrochemical characterizations, we reveal that the dealloyed AuCu core-shell nanoparticles can effectively promote the deposition of PtML closer to a smooth monolayer structure, thus leading to a higher utilization efficiency of Pt and higher intrinsic activity towards methanol oxidation compared to those on pure Au nanoparticles. Moreover, the PtML deposited on the AuCu core-shell NPs showed substantially enhanced stability compared to those on pure Au NPs during long-term electrocatalysis over several hours, during which segregation of Cu to the Au/Pt interface was revealed and suggested to play an important role in stabilizing the PtML catalysts.
2020, 31(3): 841-845
doi: 10.1016/j.cclet.2019.06.017
Abstract:
We report on the synthesis of two acentric and one centrosymmetric Zn metal-organic complexes with 3-tetrazolemethyl pyridine spacers obtained in situ by hydrothermal routes. X-ray diffraction structural analysis reveals that they have the same equivalent nodes but with dissimilar topologies. The two acentric frameworks[Zn(Tzmp)Cl]n (1) and ([Zn(Tzmp)Br]n (2), HTzmp=3-tetrazolemethyl pyridine) are isomorphism which exhibit an acentric 3D framework with (10, 3)-b net called "ths", while the centrosymmetric complex ([Zn(Tzmp)N3]n (3)) features a distinctive 2D sheet with Shubnikov hexagonal plane net. Photo-luminescent studies suggest the ligand-field strength of coordinated negative ions (Cl- > Br- > N3-) has ordered adjusting effects on the emission redshift. The second harmonic generation (SHG) measurement shows that compounds 1 and 2 are nonlinear optically active, with SHG responses being 2/3 and half of the standard potassium dihydrogen phosphate (KDP), respectively.
We report on the synthesis of two acentric and one centrosymmetric Zn metal-organic complexes with 3-tetrazolemethyl pyridine spacers obtained in situ by hydrothermal routes. X-ray diffraction structural analysis reveals that they have the same equivalent nodes but with dissimilar topologies. The two acentric frameworks[Zn(Tzmp)Cl]n (1) and ([Zn(Tzmp)Br]n (2), HTzmp=3-tetrazolemethyl pyridine) are isomorphism which exhibit an acentric 3D framework with (10, 3)-b net called "ths", while the centrosymmetric complex ([Zn(Tzmp)N3]n (3)) features a distinctive 2D sheet with Shubnikov hexagonal plane net. Photo-luminescent studies suggest the ligand-field strength of coordinated negative ions (Cl- > Br- > N3-) has ordered adjusting effects on the emission redshift. The second harmonic generation (SHG) measurement shows that compounds 1 and 2 are nonlinear optically active, with SHG responses being 2/3 and half of the standard potassium dihydrogen phosphate (KDP), respectively.
2020, 31(3): 846-850
doi: 10.1016/j.cclet.2019.06.044
Abstract:
High-performance anodes of sodium ion batteries (SIBs) largely depends on rational architecture design and binder-free smart hybridization. Herein, we report TiC/C core/shell nanowires arrays prepared by a one-step chemical vapor deposition (CVD) method and apply it as the anode of SIBs for the first time. The conductive TiC core is intimately decorated with carbon shell. The as-obtained TiC/C nanowires are homogeneously grown on the substrate and show core/shell heterostructure and porous architecture with high electronic conductivity and reinforced stability. Owing to these merits, the TiC/C electrode displays good rate performance and outstanding cycling performance with a capacity of 135.3 mAh/g at 0.1 A/g and superior capacity retention of 90.14% after 1000 cycles at 2 A/g. The reported strategy would provide a promising way to construct binder-free arrays electrodes for sodium ion storage.
High-performance anodes of sodium ion batteries (SIBs) largely depends on rational architecture design and binder-free smart hybridization. Herein, we report TiC/C core/shell nanowires arrays prepared by a one-step chemical vapor deposition (CVD) method and apply it as the anode of SIBs for the first time. The conductive TiC core is intimately decorated with carbon shell. The as-obtained TiC/C nanowires are homogeneously grown on the substrate and show core/shell heterostructure and porous architecture with high electronic conductivity and reinforced stability. Owing to these merits, the TiC/C electrode displays good rate performance and outstanding cycling performance with a capacity of 135.3 mAh/g at 0.1 A/g and superior capacity retention of 90.14% after 1000 cycles at 2 A/g. The reported strategy would provide a promising way to construct binder-free arrays electrodes for sodium ion storage.
2020, 31(3): 851-854
doi: 10.1016/j.cclet.2019.05.057
Abstract:
In this work, we adopt a new tobramycin (TOB)-dopamine coating system to endow thin film composite membranes with excellent antifouling and antimicrobial properties. Combining the hydrophilic and antibiofouling properties of both TOB and polydopamine, the TOB-dopamine modified membrane exhibits improved antifouling and antimicrobial properties compared with the conventional dopamine modified and unmodified membranes. The TOB-dopamine system has two advantages over the conventional modification with dopamine and tris buffer solution. First, TOB-dopamine modification is more efficient than the conventional dopamine modification due to the accelerating effect of TOB on dopamine polymerization. Second, the TOB-dopamine modified membranes exhibit better hydrophilicity, and enhanced antifouling and antimicrobial properties than the conventional dopamine modified membrane. Beyond engineering membranes, the proposed TOB-dopamine system can also be extended for wider surface hydrophilic and antimicrobial modifications.
In this work, we adopt a new tobramycin (TOB)-dopamine coating system to endow thin film composite membranes with excellent antifouling and antimicrobial properties. Combining the hydrophilic and antibiofouling properties of both TOB and polydopamine, the TOB-dopamine modified membrane exhibits improved antifouling and antimicrobial properties compared with the conventional dopamine modified and unmodified membranes. The TOB-dopamine system has two advantages over the conventional modification with dopamine and tris buffer solution. First, TOB-dopamine modification is more efficient than the conventional dopamine modification due to the accelerating effect of TOB on dopamine polymerization. Second, the TOB-dopamine modified membranes exhibit better hydrophilicity, and enhanced antifouling and antimicrobial properties than the conventional dopamine modified membrane. Beyond engineering membranes, the proposed TOB-dopamine system can also be extended for wider surface hydrophilic and antimicrobial modifications.
2020, 31(3): 855-858
doi: 10.1016/j.cclet.2019.06.021
Abstract:
Highly efficient, cost-effective, and durable electrocatalysts for hydrogen evolution reaction (HER) in water splitting is crucial for energy conversion and storage. Herein, we report NiCoP 1D nanothorn arrays grown on 3D porous Ni film current collectors (Ni/NiCoP) as the novel electrocatalytic electrodes. The 3D hierarchically porous nickel films containing large 7 ± 2 μm pores and small pores less than 1 μm are obtained through using hydrogen bubbles dynamic template method. The NiCoP 1D nanothorns are about 70 nm in diameter and 4-8 μm in length. The porous Ni/NiCoP electrocatalytic electrodes demonstrate much higher catalytic activity and remarkable stability for long-term HER. The excellent electrocatalytic performance might be attributed to the inherent nature of highly catalytic active NiCo bimetal phosphides and the unique architecture of 1D nanothorn active materials directly integrated on the 3D hierarchically porous metallic nickel conductive skeletons. The developed electrode has been fabricated to the integrated solar-driven seawater-splitting system.
Highly efficient, cost-effective, and durable electrocatalysts for hydrogen evolution reaction (HER) in water splitting is crucial for energy conversion and storage. Herein, we report NiCoP 1D nanothorn arrays grown on 3D porous Ni film current collectors (Ni/NiCoP) as the novel electrocatalytic electrodes. The 3D hierarchically porous nickel films containing large 7 ± 2 μm pores and small pores less than 1 μm are obtained through using hydrogen bubbles dynamic template method. The NiCoP 1D nanothorns are about 70 nm in diameter and 4-8 μm in length. The porous Ni/NiCoP electrocatalytic electrodes demonstrate much higher catalytic activity and remarkable stability for long-term HER. The excellent electrocatalytic performance might be attributed to the inherent nature of highly catalytic active NiCo bimetal phosphides and the unique architecture of 1D nanothorn active materials directly integrated on the 3D hierarchically porous metallic nickel conductive skeletons. The developed electrode has been fabricated to the integrated solar-driven seawater-splitting system.
2020, 31(3): 859-864
doi: 10.1016/j.cclet.2019.06.032
Abstract:
A facile and efficient strategy has been developed to fabricate a multifunctional, theranostic anticancer drug delivery platform featuring active targeting, controlled drug release and fluorescence imaging for real-time control of delivery. To this end, thermosensitive poly(N-isopropyl acrylamide) (PNIPAM) nanospheres are decorated with peptide-Au cluster conjugates as a smart nanomedicine platform. A sophisticated trifunctional peptide is designed to release the anticancer drug doxorubicin (DOX), target cells and reduce Au3+ ions to form luminescent Au clusters. Importantly, the peptide-Au cluster moieties are attached to the PNIPAM nanospheres via amide bonds rather than noncovalent interactions, significantly improving their stability in biological medium and drug release efficiency. The in vitro experiments showed that DOX was released in an efficient and controlled manner under physiological conditions.
A facile and efficient strategy has been developed to fabricate a multifunctional, theranostic anticancer drug delivery platform featuring active targeting, controlled drug release and fluorescence imaging for real-time control of delivery. To this end, thermosensitive poly(N-isopropyl acrylamide) (PNIPAM) nanospheres are decorated with peptide-Au cluster conjugates as a smart nanomedicine platform. A sophisticated trifunctional peptide is designed to release the anticancer drug doxorubicin (DOX), target cells and reduce Au3+ ions to form luminescent Au clusters. Importantly, the peptide-Au cluster moieties are attached to the PNIPAM nanospheres via amide bonds rather than noncovalent interactions, significantly improving their stability in biological medium and drug release efficiency. The in vitro experiments showed that DOX was released in an efficient and controlled manner under physiological conditions.
2020, 31(3): 865-868
doi: 10.1016/j.cclet.2019.06.051
Abstract:
In this work, ternary organic solar cells (OSCs) combining a fullerene derivative PC71BM with a nonfullerene acceptor N2200-F blended with a polymer donor PM6 were reported. Compared with the binary systems, the highest power conversion efficiency (PCE) of 8.11% was achieved in ternary solar cells with 30 wt% N2200-F content, mainly due to the improved short-circuit current density (Jsc) and fill factor (FF). Further studies showed that the improved Jsc could attribute to the complementary absorption of the two acceptors and the enhanced FF was originated from the higher hole mobility and the fine-tuned morphology in the ternary system. These results demonstrate that the combination of fullerene and nonfullerene acceptors in ternary organic solar cells is a promising approach to achieve high-performance OSCs.
In this work, ternary organic solar cells (OSCs) combining a fullerene derivative PC71BM with a nonfullerene acceptor N2200-F blended with a polymer donor PM6 were reported. Compared with the binary systems, the highest power conversion efficiency (PCE) of 8.11% was achieved in ternary solar cells with 30 wt% N2200-F content, mainly due to the improved short-circuit current density (Jsc) and fill factor (FF). Further studies showed that the improved Jsc could attribute to the complementary absorption of the two acceptors and the enhanced FF was originated from the higher hole mobility and the fine-tuned morphology in the ternary system. These results demonstrate that the combination of fullerene and nonfullerene acceptors in ternary organic solar cells is a promising approach to achieve high-performance OSCs.
2020, 31(3): 869-874
doi: 10.1016/j.cclet.2019.07.013
Abstract:
Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or hydrogels. The construction of these functional materials usually requires the pre-synthesis of macromolecular building blocks, and direct gelation between natural polyphenols and small molecule boronic acids is yet to be investigated. In this study, we fabricated a family of allsmall-molecule dynamic covalent gels consisting of tannic acid and boronic acids. Transparent and thixotropic gels were formed by boronate affinity towards catechol groups abundant on natural polyphenols. The gels showed multi-responsiveness, such as acid-, base-, reduction-and oxidantsensitive depending on the used boronic acid building blocks. The chemistry for gel formation and stimuli-responsiveness was characterized by 11B NMR spectroscopy. The multi-stimuli responsiveness, green processing and facile modular design make the boronic acid-tannic acid gels promising candidates for the development of smart soft materials.
Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or hydrogels. The construction of these functional materials usually requires the pre-synthesis of macromolecular building blocks, and direct gelation between natural polyphenols and small molecule boronic acids is yet to be investigated. In this study, we fabricated a family of allsmall-molecule dynamic covalent gels consisting of tannic acid and boronic acids. Transparent and thixotropic gels were formed by boronate affinity towards catechol groups abundant on natural polyphenols. The gels showed multi-responsiveness, such as acid-, base-, reduction-and oxidantsensitive depending on the used boronic acid building blocks. The chemistry for gel formation and stimuli-responsiveness was characterized by 11B NMR spectroscopy. The multi-stimuli responsiveness, green processing and facile modular design make the boronic acid-tannic acid gels promising candidates for the development of smart soft materials.
2020, 31(3): 875-879
doi: 10.1016/j.cclet.2019.07.016
Abstract:
The discrimination against nutritional fat emulsion injections was considered by imaging tools, which aims to elucidate the in vivo behaviors of nanoemulsions. In this study, 20% nutritional fat emulsion injections were selected from different company including original and generic products. Meanwhile, a water quenching fluorescent probe (P2) was used to label them by an incubation method. The fluorescent intensity analysis of blood-borne fluorescence reveals rapid clearance of nanoemulsion in all groups, which shows 'L'-type blood kinetic profiles. However, these kinetic parameters do not have significant difference. Following intravenous administration, the nanoemulsions in all groups concomitantly accumulated in organs of reticulo-endothelial system (RES), such as liver and spleen, and were cleared from body circulation mostly after 12 h. AUC(0-t) of organs from different groups showed dissimilar results in some organs. These intuitional results are of significance in understanding the in vivo behaviors of nanoemulsions, which can provide a new way to discriminate against nutritional fat emulsions.
The discrimination against nutritional fat emulsion injections was considered by imaging tools, which aims to elucidate the in vivo behaviors of nanoemulsions. In this study, 20% nutritional fat emulsion injections were selected from different company including original and generic products. Meanwhile, a water quenching fluorescent probe (P2) was used to label them by an incubation method. The fluorescent intensity analysis of blood-borne fluorescence reveals rapid clearance of nanoemulsion in all groups, which shows 'L'-type blood kinetic profiles. However, these kinetic parameters do not have significant difference. Following intravenous administration, the nanoemulsions in all groups concomitantly accumulated in organs of reticulo-endothelial system (RES), such as liver and spleen, and were cleared from body circulation mostly after 12 h. AUC(0-t) of organs from different groups showed dissimilar results in some organs. These intuitional results are of significance in understanding the in vivo behaviors of nanoemulsions, which can provide a new way to discriminate against nutritional fat emulsions.
2020, 31(3): 880-884
doi: 10.1016/j.cclet.2019.07.034
Abstract:
Cu@Ag/Bi2Te3 nanocomposites were prepared for the first time by ultrasonic dispersion-rapid freezedrying method combined with spark plasma sintering (SPS). By changing the content of Cu@Ag nanoparticle, we could modulate the temperature dependent thermoelectric properties. The highest ZT value can be obtained at 450 K for 1 vol% Cu@Ag/Bi2Te3, which is benefited from the decoupling of electrical and thermal properties. With the increase of electrical conductivity, the absolute value of Seebeck coefficient lifts while the thermal conductivity declines. Meanwhile, the average ZT value between 300 K and 475 K was 0.61 for 1 vol% Cu@Ag/Bi2Te3, which is much higher than that of pristine Bi2Te3. Therefore, the decoupling effect of Cu@Ag nanoparticles incorporation could be a promising method to broaden the application of Bi2Te3 based thermoelectric materials.
Cu@Ag/Bi2Te3 nanocomposites were prepared for the first time by ultrasonic dispersion-rapid freezedrying method combined with spark plasma sintering (SPS). By changing the content of Cu@Ag nanoparticle, we could modulate the temperature dependent thermoelectric properties. The highest ZT value can be obtained at 450 K for 1 vol% Cu@Ag/Bi2Te3, which is benefited from the decoupling of electrical and thermal properties. With the increase of electrical conductivity, the absolute value of Seebeck coefficient lifts while the thermal conductivity declines. Meanwhile, the average ZT value between 300 K and 475 K was 0.61 for 1 vol% Cu@Ag/Bi2Te3, which is much higher than that of pristine Bi2Te3. Therefore, the decoupling effect of Cu@Ag nanoparticles incorporation could be a promising method to broaden the application of Bi2Te3 based thermoelectric materials.
2020, 31(3): 885-889
doi: 10.1016/j.cclet.2019.07.035
Abstract:
Based on block copolymer assisted topochemical polymerization, a new strategy for facilely producing robust nanoporous membranes with controlled incorporation of functional groups onto nanopores is developed. As exemplified by preparing nanoporous polypyrrole decorated with amino acids, this strategy exhibits a high degree of freedom for tailoring the surface functionality in the created pores.
Based on block copolymer assisted topochemical polymerization, a new strategy for facilely producing robust nanoporous membranes with controlled incorporation of functional groups onto nanopores is developed. As exemplified by preparing nanoporous polypyrrole decorated with amino acids, this strategy exhibits a high degree of freedom for tailoring the surface functionality in the created pores.
2020, 31(3): 890-896
doi: 10.1016/j.cclet.2019.12.006
Abstract:
Bimetallic nanoparticles (AmBn) usually exhibit rich catalytic chemistry and have drawn tremendous attention in heterogeneous catalysis. However, challenged by the huge configuration space, the understanding toward their composition and distribution of A/B element is known little at the atomic level, which hinders the rational synthesis. Herein, we develop an on-the-fly training strategy combing the machine learning model (SchNet) with the genetic algorithm (GA) search technique, which achieve the fast and accurate energy prediction of complex bimetallic clusters at the DFT level. Taking the 38-atom PtmAu38-m nanoparticle as example, the element distribution identification problem and the stability trend as a function of Pt/Au composition is quantitatively resolved. Specifically, results show that on the Pt-rich cluster Au atoms prefer to occupy the low-coordinated surface corner sites and form patch-like surface segregation patterns, while for the Au-rich ones Pt atoms tend to site in the core region and form the core-shell (Pt@Au) configuration. The thermodynamically most stable PtmAu38-m cluster is Pt6Au32, with all the core-region sites occupied by Pt, rationalized by the stronger Pt-Pt bond in comparison with Pt-Au and Au-Au bonds. This work exemplifies the potent application of rapid global search enabled by machine learning in exploring the high-dimensional configuration space of bimetallic nanocatalysts.
Bimetallic nanoparticles (AmBn) usually exhibit rich catalytic chemistry and have drawn tremendous attention in heterogeneous catalysis. However, challenged by the huge configuration space, the understanding toward their composition and distribution of A/B element is known little at the atomic level, which hinders the rational synthesis. Herein, we develop an on-the-fly training strategy combing the machine learning model (SchNet) with the genetic algorithm (GA) search technique, which achieve the fast and accurate energy prediction of complex bimetallic clusters at the DFT level. Taking the 38-atom PtmAu38-m nanoparticle as example, the element distribution identification problem and the stability trend as a function of Pt/Au composition is quantitatively resolved. Specifically, results show that on the Pt-rich cluster Au atoms prefer to occupy the low-coordinated surface corner sites and form patch-like surface segregation patterns, while for the Au-rich ones Pt atoms tend to site in the core region and form the core-shell (Pt@Au) configuration. The thermodynamically most stable PtmAu38-m cluster is Pt6Au32, with all the core-region sites occupied by Pt, rationalized by the stronger Pt-Pt bond in comparison with Pt-Au and Au-Au bonds. This work exemplifies the potent application of rapid global search enabled by machine learning in exploring the high-dimensional configuration space of bimetallic nanocatalysts.
2020, 31(3): 897-902
doi: 10.1016/j.cclet.2019.07.039
Abstract:
It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomaterials can be significantly improved by an incorporation of carbon additives. In the study, we develop a novel Ndoped TiO2 mesoporous nanostructure via the addition of carbon quantum dots (CQDs) solution following a scalable hydrothermal process. The as-made TiO2 product shows well-defined morphology, high conductivity, large surface area, and abundant mesopores. When evaluated as anodes for sodiumion batteries, the CQDs@TiO2 product annealed at 500℃ exhibits a superior sodium storage capability. It delivers a high reversible capacity of 168.8 mAh/g at 100 mA/g over 500 cycles and long cycling stability. The remarkable performance of CQDs@TiO2 mainly arises from the large surface area and mesoporous architecture constructed by ultrathin TiO2 nanosheets, as well as the full cooperation between CQDs and TiO2.
It has been demonstrated that the conductivity and electrochemical properties of TiO2 nanomaterials can be significantly improved by an incorporation of carbon additives. In the study, we develop a novel Ndoped TiO2 mesoporous nanostructure via the addition of carbon quantum dots (CQDs) solution following a scalable hydrothermal process. The as-made TiO2 product shows well-defined morphology, high conductivity, large surface area, and abundant mesopores. When evaluated as anodes for sodiumion batteries, the CQDs@TiO2 product annealed at 500℃ exhibits a superior sodium storage capability. It delivers a high reversible capacity of 168.8 mAh/g at 100 mA/g over 500 cycles and long cycling stability. The remarkable performance of CQDs@TiO2 mainly arises from the large surface area and mesoporous architecture constructed by ultrathin TiO2 nanosheets, as well as the full cooperation between CQDs and TiO2.
2020, 31(3): 903-908
doi: 10.1016/j.cclet.2019.09.048
Abstract:
The energy density of non-aqueous carbon-based electrochemical capacitors (cEC) is mainly determined by the specific capacitance and operational voltage range. In this study, we propose to construct an unbalanced structure to make full use of stable voltage range for improving energy density. The stable voltage range is firstly carefully explored using cyclic voltammetry. Then an unbalanced carbon-based electrochemical capacitor (ucEC) is constructed with an optimized positive electrode to negative electrode weight ratio and voltage range. Its electrochemical performance is comprehensively investigated, including energy density, power density as well as cycle life. The ucEC is capable to deliver an improved energy density up to 64.9 Wh/kg (1.4 times as high as a general cEC) without sacrificing the power density and cycle life. The electrode properties after cycling are also analyzed, illustrating the change of electrode potential caused by unbalanced structure. The proposed structure demonstrates a great potential for improving the energy density at little cost of electrode design and cell configuration.
The energy density of non-aqueous carbon-based electrochemical capacitors (cEC) is mainly determined by the specific capacitance and operational voltage range. In this study, we propose to construct an unbalanced structure to make full use of stable voltage range for improving energy density. The stable voltage range is firstly carefully explored using cyclic voltammetry. Then an unbalanced carbon-based electrochemical capacitor (ucEC) is constructed with an optimized positive electrode to negative electrode weight ratio and voltage range. Its electrochemical performance is comprehensively investigated, including energy density, power density as well as cycle life. The ucEC is capable to deliver an improved energy density up to 64.9 Wh/kg (1.4 times as high as a general cEC) without sacrificing the power density and cycle life. The electrode properties after cycling are also analyzed, illustrating the change of electrode potential caused by unbalanced structure. The proposed structure demonstrates a great potential for improving the energy density at little cost of electrode design and cell configuration.
2020, 31(3): 909-914
doi: 10.1016/j.cclet.2019.11.039
Abstract:
Antimony-based materials have become promising anodes within lithium-ion batteries (LIBs) due to their low cost and the high theoretical capacity. However, there is a potential to further enhance the electrochemical performance of such antimony-based materials. Herein, Sb2Se3@C nanofibers (Sb2Se3@CNFs) are designed and obtained via a novel electrospinning method. Upon electrochemically testing as an anode within LIBs, the Sb2Se3@CNFs (annealed at 600 ℃) delivers a remarkably good cycling performance of 625 mAh/g at 100 mA/g after 100 cycles. Moreover, it still remains at 490 mAh/g after 500 cycles with an applied current density of 1.0 A/g. The excellent performance of the Sb2Se3@CNFs can be attributed to the fact that the N-doped C matrices not only remit the volume expansion of materials, but also enhance the electrical and ionic conductivity thusly increasing the lithium-ion diffusion. The obtained Sb2Se3@CNFs are promising anode for LIBs in the future.
Antimony-based materials have become promising anodes within lithium-ion batteries (LIBs) due to their low cost and the high theoretical capacity. However, there is a potential to further enhance the electrochemical performance of such antimony-based materials. Herein, Sb2Se3@C nanofibers (Sb2Se3@CNFs) are designed and obtained via a novel electrospinning method. Upon electrochemically testing as an anode within LIBs, the Sb2Se3@CNFs (annealed at 600 ℃) delivers a remarkably good cycling performance of 625 mAh/g at 100 mA/g after 100 cycles. Moreover, it still remains at 490 mAh/g after 500 cycles with an applied current density of 1.0 A/g. The excellent performance of the Sb2Se3@CNFs can be attributed to the fact that the N-doped C matrices not only remit the volume expansion of materials, but also enhance the electrical and ionic conductivity thusly increasing the lithium-ion diffusion. The obtained Sb2Se3@CNFs are promising anode for LIBs in the future.
2020, 31(3): 915-918
doi: 10.1016/j.cclet.2020.01.008
Abstract:
β-Elemene is a volatile oil used for the treatment of cancer, but poor solubility, low bioavailability, and various adverse reactions limit its application. For ameliorating risks of the venous toxicity of β-elemene, intravenously injectable micelle of β-elemene was prepared using the thin-film hydration method. The results pointed out the micelles were uniformly spherical with about 20.96 ± 0.1966 nm in average diameter and exhibited high entrapment efficiency (99.02% ± 0.88%). As revealed by drug release studies in vitro, β-elemene micelles had sustained drug release. Compared with free β-elemene, the micelles increased the drug cellular uptake and enhanced the anti-tumor effect in vitro through retarding cell cycle and inducing apoptosis. Meanwhile, the elevated serum stability of β-elemene micelles implied less drug leakage and reduced toxicity. The wound healing and tube formation assay in vitro demonstrated the anti-metastasis and anti-angiogenesis effects of β-elemene micelles. Moreover, the pharmacokinetics study showed the AUC and T1/2 of β-elemene in micelle group were 1.79 and 1.62 times of that in free β-elemene group, suggesting the circulation time of β-elemene in the blood had been prolonged. In addition, β-elemene micelles showed a favorable antitumor response compared with the β-elemene solution on C26 colon cancer-bearing mice model. Local irritation study investigated in rabbits indicated that the β-elemene micelles strikingly mitigated the irritation to the injection sites compared with free β-elemene. These results proved that the micelle could be a good candidate as an auspicious drug delivery system of β-elemene for the prospective clinical treatment of carcinoma.
β-Elemene is a volatile oil used for the treatment of cancer, but poor solubility, low bioavailability, and various adverse reactions limit its application. For ameliorating risks of the venous toxicity of β-elemene, intravenously injectable micelle of β-elemene was prepared using the thin-film hydration method. The results pointed out the micelles were uniformly spherical with about 20.96 ± 0.1966 nm in average diameter and exhibited high entrapment efficiency (99.02% ± 0.88%). As revealed by drug release studies in vitro, β-elemene micelles had sustained drug release. Compared with free β-elemene, the micelles increased the drug cellular uptake and enhanced the anti-tumor effect in vitro through retarding cell cycle and inducing apoptosis. Meanwhile, the elevated serum stability of β-elemene micelles implied less drug leakage and reduced toxicity. The wound healing and tube formation assay in vitro demonstrated the anti-metastasis and anti-angiogenesis effects of β-elemene micelles. Moreover, the pharmacokinetics study showed the AUC and T1/2 of β-elemene in micelle group were 1.79 and 1.62 times of that in free β-elemene group, suggesting the circulation time of β-elemene in the blood had been prolonged. In addition, β-elemene micelles showed a favorable antitumor response compared with the β-elemene solution on C26 colon cancer-bearing mice model. Local irritation study investigated in rabbits indicated that the β-elemene micelles strikingly mitigated the irritation to the injection sites compared with free β-elemene. These results proved that the micelle could be a good candidate as an auspicious drug delivery system of β-elemene for the prospective clinical treatment of carcinoma.
