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2019 Volume 30 Issue 1
2019, 30(1): 1-6
doi: 10.1016/j.cclet.2018.04.021
Abstract:
Now increasing chemical modifications are discovered on genomic DNA and RNA. Up to date, more than 150 chemical modifications are identified in nucleic acids. These chemical modifications do not change the sequence of DNA and RNA, but alter their structures and biochemical properties, and eventually control or regulate the spatial and temporal expression of genes. Elucidation of the functional roles of these modifications is vital to our understanding of living organisms. However, the modifications in DNA and RNA generally have extremely low abundance in vivo. Therefore, sensitive and specific detection methods are essential to decipher the functional roles of these modifications. Chemical derivatization in combination with mass spectrometry (MS) analysis has been proved to be a promising strategy to efficiently analyze these modifications in DNA and RNA. In the last several years, many chemical derivatization-MS-based analytical methods were established for the sensitive and effective analysis of nucleic acid modifications. In this review, we summarize the recent advances for deciphering modifications in DNA and RNA by chemical derivatization-MS analysis. We hope this review can stimulate the future studies of DNA and RNA modifications.
Now increasing chemical modifications are discovered on genomic DNA and RNA. Up to date, more than 150 chemical modifications are identified in nucleic acids. These chemical modifications do not change the sequence of DNA and RNA, but alter their structures and biochemical properties, and eventually control or regulate the spatial and temporal expression of genes. Elucidation of the functional roles of these modifications is vital to our understanding of living organisms. However, the modifications in DNA and RNA generally have extremely low abundance in vivo. Therefore, sensitive and specific detection methods are essential to decipher the functional roles of these modifications. Chemical derivatization in combination with mass spectrometry (MS) analysis has been proved to be a promising strategy to efficiently analyze these modifications in DNA and RNA. In the last several years, many chemical derivatization-MS-based analytical methods were established for the sensitive and effective analysis of nucleic acid modifications. In this review, we summarize the recent advances for deciphering modifications in DNA and RNA by chemical derivatization-MS analysis. We hope this review can stimulate the future studies of DNA and RNA modifications.
2019, 30(1): 7-14
doi: 10.1016/j.cclet.2018.06.011
Abstract:
Metastasis is the leading cause of death in people with cancer. In the series of steps comprising metastasis process, mechanochemistry plays crucial roles. In this review, we introduced the mechanical factors in cancer cell metastasis, intracellular mechanical sensors and methods for measuring the mechanical forces of tumor cells. The recent researches on the contribution of mechanochemistry to metastasis and future perspectives were summarized.
Metastasis is the leading cause of death in people with cancer. In the series of steps comprising metastasis process, mechanochemistry plays crucial roles. In this review, we introduced the mechanical factors in cancer cell metastasis, intracellular mechanical sensors and methods for measuring the mechanical forces of tumor cells. The recent researches on the contribution of mechanochemistry to metastasis and future perspectives were summarized.
2019, 30(1): 15-24
doi: 10.1016/j.cclet.2018.04.032
Abstract:
Lignin is one of the most important biomass resources. With the increasing consumption of petroleum resource, lignin transformation is of strategic significance and has attracted widely interest. As lignin is a random construction of aromatic monomers, the degradation products are usually very complex, which limits the scaling application of lignin as feedstock for valuable chemicals. Thus, it is desperately desired to develop highly selective approach to lignin conversion. This review first gives a brief introduction to the structure of lignin, and then summarized the methods for selective transformation of lignin into phenols, aldehydes, carboxylic acids, alkanes and arenes. Finally, the challenges and opportunities of lignin selective transformation are discussed.
Lignin is one of the most important biomass resources. With the increasing consumption of petroleum resource, lignin transformation is of strategic significance and has attracted widely interest. As lignin is a random construction of aromatic monomers, the degradation products are usually very complex, which limits the scaling application of lignin as feedstock for valuable chemicals. Thus, it is desperately desired to develop highly selective approach to lignin conversion. This review first gives a brief introduction to the structure of lignin, and then summarized the methods for selective transformation of lignin into phenols, aldehydes, carboxylic acids, alkanes and arenes. Finally, the challenges and opportunities of lignin selective transformation are discussed.
2019, 30(1): 25-30
doi: 10.1016/j.cclet.2018.07.006
Abstract:
The development of donor-acceptor (D-A) conjugated polymers greatly promotes the device performance in organic electronics. Recently, the strategy of embedding pyridine units into D-A conjugated polymer backbones has attracted much attention due to the resulted lowered LUMO levels. In addition, the possible non-bonding interactions resulted from the nitrogen atoms also improve the coplanarity of the polymer backbones. All these factors have great contribution to enhance the device performance. In this review, we summarized the recent development of pyridine-embedded D-A conjugated polymers and their applications in organic field-effect transistors (OFETs).
The development of donor-acceptor (D-A) conjugated polymers greatly promotes the device performance in organic electronics. Recently, the strategy of embedding pyridine units into D-A conjugated polymer backbones has attracted much attention due to the resulted lowered LUMO levels. In addition, the possible non-bonding interactions resulted from the nitrogen atoms also improve the coplanarity of the polymer backbones. All these factors have great contribution to enhance the device performance. In this review, we summarized the recent development of pyridine-embedded D-A conjugated polymers and their applications in organic field-effect transistors (OFETs).
2019, 30(1): 31-36
doi: 10.1016/j.cclet.2018.05.034
Abstract:
Artificial light-harvesting systems (LHSs) have drawn increasing research interest in recent times due to the energy crisis worldwide. Concurrently, macrocycle-based host-guest interactions have played an important role in the development of supramolecular chemistry. In recent years, studies towards artificial LHSs driven by macrocycle-based host-guest interactions are gradually being disclosed. In this mini-review, we briefly introduce the burgeoning progress of artificial LHSs driven by host-guest interactions. We believe that an increasing number of reports of artificial LHSs driven by host-guest interactions will appear in the near future and will provide a viable alternative for the future production of renewable energy.
Artificial light-harvesting systems (LHSs) have drawn increasing research interest in recent times due to the energy crisis worldwide. Concurrently, macrocycle-based host-guest interactions have played an important role in the development of supramolecular chemistry. In recent years, studies towards artificial LHSs driven by macrocycle-based host-guest interactions are gradually being disclosed. In this mini-review, we briefly introduce the burgeoning progress of artificial LHSs driven by host-guest interactions. We believe that an increasing number of reports of artificial LHSs driven by host-guest interactions will appear in the near future and will provide a viable alternative for the future production of renewable energy.
2019, 30(1): 37-43
doi: 10.1016/j.cclet.2018.10.022
Abstract:
Supramolecular polymers, which combined of the supramolecular chemistry and polymer science, are constructed from monomers together by reversible noncovalent interactions. Supramolecular polymers in aqueous solution are especially important due to their superior biocompatibility and environmental adaptation, which determined they have wide applications in various areas, such as drug delivery, selfhealing, shape memory. Macrocyclic compounds, such as cyclodextrins, calixarenes, cucurbiturils and pillar[n]arenes, are the most used building blocks in the preparation of supramolecular polymers. Macrocycle-based supramolecular polymers, which introduce the host-guest interaction in the system, endow these polymers with interesting and smart physical-chemical properties. In this review, we summarized recent studies about supramolecular polymers in aqueous solution based on macrocyclic compounds.
Supramolecular polymers, which combined of the supramolecular chemistry and polymer science, are constructed from monomers together by reversible noncovalent interactions. Supramolecular polymers in aqueous solution are especially important due to their superior biocompatibility and environmental adaptation, which determined they have wide applications in various areas, such as drug delivery, selfhealing, shape memory. Macrocyclic compounds, such as cyclodextrins, calixarenes, cucurbiturils and pillar[n]arenes, are the most used building blocks in the preparation of supramolecular polymers. Macrocycle-based supramolecular polymers, which introduce the host-guest interaction in the system, endow these polymers with interesting and smart physical-chemical properties. In this review, we summarized recent studies about supramolecular polymers in aqueous solution based on macrocyclic compounds.
2019, 30(1): 44-46
doi: 10.1016/j.cclet.2018.10.030
Abstract:
A novel alkaloid, chartrenoline (1), featuring an unusual 6/6/5/5-tetracyclic nucleus, was isolated from a marine Streptomyces chartreusis NA02069. The structure of 1 including its absolute configurations was established by extensive analyses of its high resolution mass, NMR and single-crystal X-ray diffraction data. A plausible biosynthetic pathway for chartrenoline (1) is proposed.
A novel alkaloid, chartrenoline (1), featuring an unusual 6/6/5/5-tetracyclic nucleus, was isolated from a marine Streptomyces chartreusis NA02069. The structure of 1 including its absolute configurations was established by extensive analyses of its high resolution mass, NMR and single-crystal X-ray diffraction data. A plausible biosynthetic pathway for chartrenoline (1) is proposed.
2019, 30(1): 47-50
doi: 10.1016/j.cclet.2017.11.033
Abstract:
Four new diterpenoids including one cis clerodane-type (1) and three highly oxygenated labdane-type diterpenes (2-4) were isolated from the aerial parts of Leonurus macranthus. Their structures were elucidated on the basis of spectroscopic data (NMR, UV, IR, and MS). Compound 1 represents the first example of cis clerodane-type diterpene in the plants of Leonurus genus. Compounds 1 and 4 exhibited weak inhibition of nitric oxide production in lipopolysaccharide-stimulated BV-2 microglial cells with IC50 values of 35.8±3.6 mmol/L and 48.6±4.8 mmol/L, respectively
Four new diterpenoids including one cis clerodane-type (1) and three highly oxygenated labdane-type diterpenes (2-4) were isolated from the aerial parts of Leonurus macranthus. Their structures were elucidated on the basis of spectroscopic data (NMR, UV, IR, and MS). Compound 1 represents the first example of cis clerodane-type diterpene in the plants of Leonurus genus. Compounds 1 and 4 exhibited weak inhibition of nitric oxide production in lipopolysaccharide-stimulated BV-2 microglial cells with IC50 values of 35.8±3.6 mmol/L and 48.6±4.8 mmol/L, respectively
2019, 30(1): 51-54
doi: 10.1016/j.cclet.2018.05.019
Abstract:
Dimericbiscognienynes B and C (1 and 2), two new diisoprenyl-cyclohexene-type meroterpenoid dimers, were isolated from Biscogniauxia sp. 71-10-1-1. Their structures, including the absolute configurations, were determined by spectroscopic analyses and ECD experiments. Meroterpenoids are special natural products that originate from mixed terpenoid-nonterpenoid pathway. As a member of meroterpenoid family, diisoprenyl-cyclohexene/ane-type meroterpenoids composed of two isoprenyl chains (C5 unit) and a cyclohexene/ane moiety (C6 unit), featuring diverse skeleton structures with wide range of bioactivities. In these reported diisoprenyl-cyclohexene/ane-type meroterpenoids, only three dimers were identified. The discovery of the two new dimers added members of this rare class of meroterpenoids.
Dimericbiscognienynes B and C (1 and 2), two new diisoprenyl-cyclohexene-type meroterpenoid dimers, were isolated from Biscogniauxia sp. 71-10-1-1. Their structures, including the absolute configurations, were determined by spectroscopic analyses and ECD experiments. Meroterpenoids are special natural products that originate from mixed terpenoid-nonterpenoid pathway. As a member of meroterpenoid family, diisoprenyl-cyclohexene/ane-type meroterpenoids composed of two isoprenyl chains (C5 unit) and a cyclohexene/ane moiety (C6 unit), featuring diverse skeleton structures with wide range of bioactivities. In these reported diisoprenyl-cyclohexene/ane-type meroterpenoids, only three dimers were identified. The discovery of the two new dimers added members of this rare class of meroterpenoids.
2019, 30(1): 55-57
doi: 10.1016/j.cclet.2018.03.016
Abstract:
Zinc plays a significant role in oxidative balance and central nervous systems. Herein, we reported a highly sensitive fluorescent probe DR, bearing a morpholine group and a BPEN ligand in the naphthalimide fluorophore. Upon Zn2+ binding, DR exhibited remarkable fluorescence enhancement, and showed high sensitivity to Zn2+ with the association constant of 4.9×108 L/mol, and the detection limit of 15 nmol/L. Confocal imaging experiments indicated that DR was able to localize to lysosomes in MCF-7 cells. Moreover, upon H2O2 stimulation in SH-SY5Y cells, endogenous release of Zn2+ was observed.
Zinc plays a significant role in oxidative balance and central nervous systems. Herein, we reported a highly sensitive fluorescent probe DR, bearing a morpholine group and a BPEN ligand in the naphthalimide fluorophore. Upon Zn2+ binding, DR exhibited remarkable fluorescence enhancement, and showed high sensitivity to Zn2+ with the association constant of 4.9×108 L/mol, and the detection limit of 15 nmol/L. Confocal imaging experiments indicated that DR was able to localize to lysosomes in MCF-7 cells. Moreover, upon H2O2 stimulation in SH-SY5Y cells, endogenous release of Zn2+ was observed.
2019, 30(1): 99-102
doi: 10.1016/j.cclet.2018.10.029
Abstract:
A novel on-line system composed of supercritical fluid extraction (SFE), dilution line and reverse phase liquid chromatography/mass spectrometry (RPLC/MS) was constructed for on-line extraction and reverse phase separation of some fat-soluble components in foods. Three columns including a trap column, concentration column and analytical column were used for trapping the fat-soluble components, on-line enrichment and reverse phase separation, respectively. Capsaicinoids were on-line extracted by a CO2 supercritical fluid, then concentrated and separated by using the C18 columns, finally detected by mass spectrometry (MS). Capsaicin eluted at 10.1 min and limit of detection (LOD, S/N=3) for the standard solution is 0.55 pg. The linearity was calculated with a value of coefficient of determination (R2)≥0.998 in the range of 1.1-8.5 ng. Concentrations of capsaicin in the green, yellow, and red bell peppers were determined to be 60.33 ng/g, 31.79 ng/g, 35.38 ng/g, respectively.
A novel on-line system composed of supercritical fluid extraction (SFE), dilution line and reverse phase liquid chromatography/mass spectrometry (RPLC/MS) was constructed for on-line extraction and reverse phase separation of some fat-soluble components in foods. Three columns including a trap column, concentration column and analytical column were used for trapping the fat-soluble components, on-line enrichment and reverse phase separation, respectively. Capsaicinoids were on-line extracted by a CO2 supercritical fluid, then concentrated and separated by using the C18 columns, finally detected by mass spectrometry (MS). Capsaicin eluted at 10.1 min and limit of detection (LOD, S/N=3) for the standard solution is 0.55 pg. The linearity was calculated with a value of coefficient of determination (R2)≥0.998 in the range of 1.1-8.5 ng. Concentrations of capsaicin in the green, yellow, and red bell peppers were determined to be 60.33 ng/g, 31.79 ng/g, 35.38 ng/g, respectively.
2019, 30(1): 103-106
doi: 10.1016/j.cclet.2017.12.023
Abstract:
The binding between NL-101, a novel nitrogen mustard anti-cancer drug, with amino acids and peptides has been investigated by high performance liquid chromatography electrospray tandem mass spectrometry (HPLC/ESI-MS/MS). This study offers supporting data of the interaction among drug and amino acids and peptides, which could potentially explain the cytotoxic and mutagenic effects of the drug. Collision-induced dissociation (CID) experiment demonstrated that under the same collision energy, the amino group combined with NL-101 adducts are sensitive and often produce more fragment ions; the carboxyl group combined with NL-101 adducts are hard to break and display fewer fragment ions. In addition, when other group (like sulfhydryl group) of amino acids binds to NL-101, CID spectra show different fragmentation pattern. These differences could display structural information about the drug adducts and be utilized as location of the authentic binding sites.
The binding between NL-101, a novel nitrogen mustard anti-cancer drug, with amino acids and peptides has been investigated by high performance liquid chromatography electrospray tandem mass spectrometry (HPLC/ESI-MS/MS). This study offers supporting data of the interaction among drug and amino acids and peptides, which could potentially explain the cytotoxic and mutagenic effects of the drug. Collision-induced dissociation (CID) experiment demonstrated that under the same collision energy, the amino group combined with NL-101 adducts are sensitive and often produce more fragment ions; the carboxyl group combined with NL-101 adducts are hard to break and display fewer fragment ions. In addition, when other group (like sulfhydryl group) of amino acids binds to NL-101, CID spectra show different fragmentation pattern. These differences could display structural information about the drug adducts and be utilized as location of the authentic binding sites.
2019, 30(1): 107-110
doi: 10.1016/j.cclet.2018.02.001
Abstract:
Commercial suspension emulsion (SE) of (8% chlorfenapyr + 20% clothianidin), as a pre-registered product in China, was firstly investigated under Chinese open-field conditions. A MWCNTs-based QuEChERS method for simultaneous determination of chlorfenapyr and clothianidin in leek was established and validated through rapid resolution liquid chromatography triples quadrupole tandem mass spectrometry (RRLC-QqQ-MS/MS). Based on this method, the dissipation behaviors, residue distributions and dietary risk probability of these fungicides in leek from two representative locations in China in 2016, which were previously treated with these insecticides at the doses of 420-630 g a.i./ha twice applications, were further investigated for food safety. Dissipation behavior of chlorfenapyr and clothianidin in leek followed first-order kinetics with the half-lives of 2.9-7.2 days, and the highest residues (HR) of these insecticides in leek were below 0.3811 mg/kg and 0.2989 mg/kg, respectively, at the pre-harvest interval (PHI, 7 days). For dietary risk assessments, the risk quotients (RQs) of chlorfenapyr and clothianidin in leek were evaluated by comparing the value of national estimated daily intake (NEDI) with acceptable daily intake (ADI), based on the trials data under good agricultural practices (GAP) conditions. The results indicated that RQs of chlorfenapyr and clothianidin in leek were 21.5% and 0.29%, respectively, which exhibited an acceptably low health risk to leek consumption. The current study could not only guide reasonable usage of the formulation, but also facilitate the setting of maximum residue limits (MRLs) of chlorfenapyr and clothianidin in leek for Chinese authorities.
Commercial suspension emulsion (SE) of (8% chlorfenapyr + 20% clothianidin), as a pre-registered product in China, was firstly investigated under Chinese open-field conditions. A MWCNTs-based QuEChERS method for simultaneous determination of chlorfenapyr and clothianidin in leek was established and validated through rapid resolution liquid chromatography triples quadrupole tandem mass spectrometry (RRLC-QqQ-MS/MS). Based on this method, the dissipation behaviors, residue distributions and dietary risk probability of these fungicides in leek from two representative locations in China in 2016, which were previously treated with these insecticides at the doses of 420-630 g a.i./ha twice applications, were further investigated for food safety. Dissipation behavior of chlorfenapyr and clothianidin in leek followed first-order kinetics with the half-lives of 2.9-7.2 days, and the highest residues (HR) of these insecticides in leek were below 0.3811 mg/kg and 0.2989 mg/kg, respectively, at the pre-harvest interval (PHI, 7 days). For dietary risk assessments, the risk quotients (RQs) of chlorfenapyr and clothianidin in leek were evaluated by comparing the value of national estimated daily intake (NEDI) with acceptable daily intake (ADI), based on the trials data under good agricultural practices (GAP) conditions. The results indicated that RQs of chlorfenapyr and clothianidin in leek were 21.5% and 0.29%, respectively, which exhibited an acceptably low health risk to leek consumption. The current study could not only guide reasonable usage of the formulation, but also facilitate the setting of maximum residue limits (MRLs) of chlorfenapyr and clothianidin in leek for Chinese authorities.
2019, 30(1): 111-114
doi: 10.1016/j.cclet.2018.01.016
Abstract:
Near infrared diffuse reflectance spectroscopy (NIRDRS) has gained wide attention due to its convenience for rapid quantitative analysis of complex samples. A method for rapid analysis of triglycerides in human serum using NIRDRS with silver mirror as the substrate is developed. Due to the even and high reflectance of the silver mirror, the spectral response is enhanced and the background interference is reduced. Furthermore, both linear and nonlinear modeling strategies were investigated adopting the partial least squares (PLS) and least squares support vector regression (LS-SVR), continuous wavelet transform (CWT) was used for spectral preprocessing, and variable selection was tried using Monte Carlo uninformative variable elimination (MC-UVE), randomization test (RT) and competitive adaptive reweighted sampling (CARS) for optimization the models. The results show that the determination coefficient (R) between the predicted and reference concentration is 0.9624 and the root mean squared error of prediction (RMSEP) is 0.21. The maximum deviation of the prediction results is as low as 0.473 mmol/L. The proposed method may provide an alternative method for routine analysis of serum triglycerides in clinical applications.
Near infrared diffuse reflectance spectroscopy (NIRDRS) has gained wide attention due to its convenience for rapid quantitative analysis of complex samples. A method for rapid analysis of triglycerides in human serum using NIRDRS with silver mirror as the substrate is developed. Due to the even and high reflectance of the silver mirror, the spectral response is enhanced and the background interference is reduced. Furthermore, both linear and nonlinear modeling strategies were investigated adopting the partial least squares (PLS) and least squares support vector regression (LS-SVR), continuous wavelet transform (CWT) was used for spectral preprocessing, and variable selection was tried using Monte Carlo uninformative variable elimination (MC-UVE), randomization test (RT) and competitive adaptive reweighted sampling (CARS) for optimization the models. The results show that the determination coefficient (R) between the predicted and reference concentration is 0.9624 and the root mean squared error of prediction (RMSEP) is 0.21. The maximum deviation of the prediction results is as low as 0.473 mmol/L. The proposed method may provide an alternative method for routine analysis of serum triglycerides in clinical applications.
2019, 30(1): 115-119
doi: 10.1016/j.cclet.2018.07.019
Abstract:
Marine microorganism accumulated on the surface of ships or pipelines would accelerate fouling organisms, such as mussels and barnacles, adhered on the surface. It was significant to understand the bio-interaction between the microorganisms and the surface. Attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy was used to study the initial stages of marine microorganism adhering to surfaces, because it could probe the microorganism interaction to the surface regardless of the water interference. Bacillus sp. and Escherichia coli were selected to study the initial attachment on different surfaces, because they were typical fouling microorganisms and showed opposite Gram stain results. The assays were conducted respectively in dried and settled bacteria on two different surfaces (ZnSe, Al2O3 coated on ZnSe). IR spectra of settled bacteria showed amide Ⅰ band red shift and amide Ⅱ band blue shift in aqueous environment on both surfaces compared with the dry bacteria. The reasons of amide bands shift were investigated and it was discovered that the hydrogen bond between the water and the protein of the bacteria led to the protein secondary structure change. ATR-FTIR provided an approach to study the attachment process and showed dynamic changing process on the surface, and it could be an appropriate approach to study the interaction between proteins and chemicals.
Marine microorganism accumulated on the surface of ships or pipelines would accelerate fouling organisms, such as mussels and barnacles, adhered on the surface. It was significant to understand the bio-interaction between the microorganisms and the surface. Attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy was used to study the initial stages of marine microorganism adhering to surfaces, because it could probe the microorganism interaction to the surface regardless of the water interference. Bacillus sp. and Escherichia coli were selected to study the initial attachment on different surfaces, because they were typical fouling microorganisms and showed opposite Gram stain results. The assays were conducted respectively in dried and settled bacteria on two different surfaces (ZnSe, Al2O3 coated on ZnSe). IR spectra of settled bacteria showed amide Ⅰ band red shift and amide Ⅱ band blue shift in aqueous environment on both surfaces compared with the dry bacteria. The reasons of amide bands shift were investigated and it was discovered that the hydrogen bond between the water and the protein of the bacteria led to the protein secondary structure change. ATR-FTIR provided an approach to study the attachment process and showed dynamic changing process on the surface, and it could be an appropriate approach to study the interaction between proteins and chemicals.
2019, 30(1): 58-62
doi: 10.1016/j.cclet.2018.02.003
Abstract:
DNAzyme that can catalytically cleave of substrate DNA has shown to be attractive for amplified detection in biosensing events. During the catalytic process, the recycling of enzyme strand of DNAzyme is critically important. In this work, a G-quadruplex-assisted enzyme strand recycling strategy was developed for amplified label-free fluorescent detection of uranyl ion (UO22+). The DNAzyme was activated by the target UO22+ and further cleaved the substrate strand that contained the G-quadruplex sequence. The following formation of G-quadruplex helps the separation between the enzyme strand and the cleaved substrate strand, thus improving the recycle use of the enzyme strand. Such strategy allowed lablel-free detection of 0.2-200 ng/mL UO22+ via SYBR green Ⅰ (SG)-based fluorescence. The detection limit (3δ) is as low as 0.06 ng/mL (about 0.2 nmol/L), comparable to those obtained by ICP-MS and labeled DNAzyme. It was applied for detection of UO22+ in spiked environmental water samples with recoveries in the range of 96%-103%. This biosensor, with the advantages of simplicity and high sensitivity, is an appealing tool for fast detection of UO22+ in environmental water samples.
DNAzyme that can catalytically cleave of substrate DNA has shown to be attractive for amplified detection in biosensing events. During the catalytic process, the recycling of enzyme strand of DNAzyme is critically important. In this work, a G-quadruplex-assisted enzyme strand recycling strategy was developed for amplified label-free fluorescent detection of uranyl ion (UO22+). The DNAzyme was activated by the target UO22+ and further cleaved the substrate strand that contained the G-quadruplex sequence. The following formation of G-quadruplex helps the separation between the enzyme strand and the cleaved substrate strand, thus improving the recycle use of the enzyme strand. Such strategy allowed lablel-free detection of 0.2-200 ng/mL UO22+ via SYBR green Ⅰ (SG)-based fluorescence. The detection limit (3δ) is as low as 0.06 ng/mL (about 0.2 nmol/L), comparable to those obtained by ICP-MS and labeled DNAzyme. It was applied for detection of UO22+ in spiked environmental water samples with recoveries in the range of 96%-103%. This biosensor, with the advantages of simplicity and high sensitivity, is an appealing tool for fast detection of UO22+ in environmental water samples.
2019, 30(1): 63-66
doi: 10.1016/j.cclet.2018.03.028
Abstract:
As an important transition metal catalyst, palladium is extensively used in many areas including electronics industry, petroleum industry, automobile industry and fine chemicals engineering. However, it brings harm to the environment as well as people's health. Herein, we managed to introduce a butynyl group to 1, 2-dioxetane developing a reaction-based chemiluminescent probe as well as an imaging approach for monitoring palladium(Ⅱ). Exhibiting enhanced total flux in Pd2+ enriched areas, palladium chemiluminescent probe (PCL) may afford potential utility for detecting Pd2+ in vitro, in cellulo and in vivo.
As an important transition metal catalyst, palladium is extensively used in many areas including electronics industry, petroleum industry, automobile industry and fine chemicals engineering. However, it brings harm to the environment as well as people's health. Herein, we managed to introduce a butynyl group to 1, 2-dioxetane developing a reaction-based chemiluminescent probe as well as an imaging approach for monitoring palladium(Ⅱ). Exhibiting enhanced total flux in Pd2+ enriched areas, palladium chemiluminescent probe (PCL) may afford potential utility for detecting Pd2+ in vitro, in cellulo and in vivo.
2019, 30(1): 67-70
doi: 10.1016/j.cclet.2018.05.030
Abstract:
Wortmannin, a known inhibitor of phosphoinositide 3-kinases (PI3Ks), their low selectivity and high toxicity is still problematic and less is known about their effects on PI3Ks in cellular systems. Hence, we have synthesized a series of multifunctional wortmannin probes with the ability to self-activate, by installing a clickable handle at C11 site, and secondary amine and cancer-targeting moiety at C20 site, respectively. MTT assay first confirmed that self-activating probes have better inhibition potency and biotin enhanced their cancer cell uptake. Further experiments showed most of probes can target PI3K/Akt/mTOR pathway with prolonged turn-over time. Protein profiling and pull-down results were observed that the derivatives not only labelled four PI3Ks with selectivity, but also engaged in covalent interactions with numerous cellular proteins which could be the major reason of their high toxicity.
Wortmannin, a known inhibitor of phosphoinositide 3-kinases (PI3Ks), their low selectivity and high toxicity is still problematic and less is known about their effects on PI3Ks in cellular systems. Hence, we have synthesized a series of multifunctional wortmannin probes with the ability to self-activate, by installing a clickable handle at C11 site, and secondary amine and cancer-targeting moiety at C20 site, respectively. MTT assay first confirmed that self-activating probes have better inhibition potency and biotin enhanced their cancer cell uptake. Further experiments showed most of probes can target PI3K/Akt/mTOR pathway with prolonged turn-over time. Protein profiling and pull-down results were observed that the derivatives not only labelled four PI3Ks with selectivity, but also engaged in covalent interactions with numerous cellular proteins which could be the major reason of their high toxicity.
2019, 30(1): 71-74
doi: 10.1016/j.cclet.2018.05.018
Abstract:
To detect monoamine oxidase B (MAO-B), the level of which is one of the most important indicators of neurodegenerative diseases such as Parkinson's disease, a new type of cascade reaction based on the formation of coumarin was applied in this research. After the reaction with MAO-B, the protecting group of hydroxyl group in probes (DEAN-MA and DEAB-MA) was removed, and the fluorescence intensity significantly increased (λem=456 nm) as the structure of coumarin was formed subsequently. The probes showed excellent sensitivity and selectivity to MAO-B. The detection limit of DEAN-MA and DEAB-MA were 0.6 ng/mL and 0.2 ng/mL, respectively. We succeeded in detecting MAO-B in vitro and imaging it in human astrocyte (U 87).
To detect monoamine oxidase B (MAO-B), the level of which is one of the most important indicators of neurodegenerative diseases such as Parkinson's disease, a new type of cascade reaction based on the formation of coumarin was applied in this research. After the reaction with MAO-B, the protecting group of hydroxyl group in probes (DEAN-MA and DEAB-MA) was removed, and the fluorescence intensity significantly increased (λem=456 nm) as the structure of coumarin was formed subsequently. The probes showed excellent sensitivity and selectivity to MAO-B. The detection limit of DEAN-MA and DEAB-MA were 0.6 ng/mL and 0.2 ng/mL, respectively. We succeeded in detecting MAO-B in vitro and imaging it in human astrocyte (U 87).
2019, 30(1): 75-78
doi: 10.1016/j.cclet.2018.06.014
Abstract:
A new fluorescent coordination polymer (NKU-115) was constructed under solvothermal condition based on Tb3+ ion and H2L (5-(4H-1, 2, 4-triazol-4-yl) benzene-1, 3-dicarboxylic acid) ligand, featuring high solvent and water stability. Luminescent investigations revealed that NKU-115 shows fluorescence quenching response toward Fe3+ in aqueous solution and the mechanism of quenching was analyzed.
A new fluorescent coordination polymer (NKU-115) was constructed under solvothermal condition based on Tb3+ ion and H2L (5-(4H-1, 2, 4-triazol-4-yl) benzene-1, 3-dicarboxylic acid) ligand, featuring high solvent and water stability. Luminescent investigations revealed that NKU-115 shows fluorescence quenching response toward Fe3+ in aqueous solution and the mechanism of quenching was analyzed.
2019, 30(1): 79-82
doi: 10.1016/j.cclet.2018.04.033
Abstract:
For the synthesis of AgInS2 quantum dots (QDs), a suitable temperature is extremely important for control of the size, shape and fluorescence properties of QDs. Most of synthesis methods for AgInS2 QDs are based on batch reactors, which bring uneven distribution of temperature, affecting their fluorescence properties and size uniformity. Here we designed a droplet microreactor with a temperature-controllable region, and successfully synthesized water-soluble AgInS2 QDs. By accurately controlling temperature, we also studied how the reaction temperature affected the fluorescence properties of AgInS2 QDs. The results showed that with the increasing of reaction temperature, the QDs size increased and the fluorescence peak constantly red-shifted along with enhanced fluorescence intensity. Based on the droplet microreactor, we could achieve more appropriate reaction condition to synthesize AgInS2 QDs with higher fluorescence quantum yield (QY) and intensity.
For the synthesis of AgInS2 quantum dots (QDs), a suitable temperature is extremely important for control of the size, shape and fluorescence properties of QDs. Most of synthesis methods for AgInS2 QDs are based on batch reactors, which bring uneven distribution of temperature, affecting their fluorescence properties and size uniformity. Here we designed a droplet microreactor with a temperature-controllable region, and successfully synthesized water-soluble AgInS2 QDs. By accurately controlling temperature, we also studied how the reaction temperature affected the fluorescence properties of AgInS2 QDs. The results showed that with the increasing of reaction temperature, the QDs size increased and the fluorescence peak constantly red-shifted along with enhanced fluorescence intensity. Based on the droplet microreactor, we could achieve more appropriate reaction condition to synthesize AgInS2 QDs with higher fluorescence quantum yield (QY) and intensity.
2019, 30(1): 83-86
doi: 10.1016/j.cclet.2018.06.005
Abstract:
This study aimed to seek necrosis avid agents with high safety from DNA binding agents. The interaction of 5-hydroxytryptophan (5-HTP) with DNA was investigated by a series of spectroscopic studies. Then, 5-HTP was labeled with iodine-131 ([131I]5-HTP) and the necrosis avidity of [131I]5-HTP was evaluated by in vitro cell binding assays, in vivo biodistribution experiments and blocking experiment. Finally, the potential of [131I]5-HTP to image necrotic myocardium was explored in rat models with myocardial infarction by SPECT/CT imaging. Results showed that 5-HTP bound to DNA in groove binding mode and the binding constant was 1.69×104 L/mol.[131I]5-HTP showed specific affinity to necrotic A549 cells, which might be related to cell nucleus. Biodistribution and autoradiography results showed preferential accumulation of [131I]5-HTP in necrotic muscle (necrotic/viable muscle ratio:6.95±0.68 at 3 h postinjection (p.i.)), which could be blocked by 5-HTP with 66.7% decline, indicating that [131I]5-HTP might share the same necrotic targets with 5-HTP. On SPECT/CT images, a hotspot was clearly observed at 3 h p.i. in the necrotic myocardium while not in the control myocardium. In conclusion, [131I]5-HTP is a novel necrosis avid agent and can rapidly visualize necrotic myocardium at 3 h p.i. The necrosis avidity mechanism of [131I]5-HTP may be attributed to its interactions with exposed DNA in the necrotic tissues.
This study aimed to seek necrosis avid agents with high safety from DNA binding agents. The interaction of 5-hydroxytryptophan (5-HTP) with DNA was investigated by a series of spectroscopic studies. Then, 5-HTP was labeled with iodine-131 ([131I]5-HTP) and the necrosis avidity of [131I]5-HTP was evaluated by in vitro cell binding assays, in vivo biodistribution experiments and blocking experiment. Finally, the potential of [131I]5-HTP to image necrotic myocardium was explored in rat models with myocardial infarction by SPECT/CT imaging. Results showed that 5-HTP bound to DNA in groove binding mode and the binding constant was 1.69×104 L/mol.[131I]5-HTP showed specific affinity to necrotic A549 cells, which might be related to cell nucleus. Biodistribution and autoradiography results showed preferential accumulation of [131I]5-HTP in necrotic muscle (necrotic/viable muscle ratio:6.95±0.68 at 3 h postinjection (p.i.)), which could be blocked by 5-HTP with 66.7% decline, indicating that [131I]5-HTP might share the same necrotic targets with 5-HTP. On SPECT/CT images, a hotspot was clearly observed at 3 h p.i. in the necrotic myocardium while not in the control myocardium. In conclusion, [131I]5-HTP is a novel necrosis avid agent and can rapidly visualize necrotic myocardium at 3 h p.i. The necrosis avidity mechanism of [131I]5-HTP may be attributed to its interactions with exposed DNA in the necrotic tissues.
2019, 30(1): 87-89
doi: 10.1016/j.cclet.2018.01.028
Abstract:
The development of multifunctional contrast agents contributes significant character in the diagnosis of cancer. However, still efforts are required to design and improve the biocompatibility of contrast agents for early detection of cancer. Herein, we synthesized splat shape Fe3O4/Au nanocomposites for multimode biomedical applications. Transmission electron microscopy (TEM) results showed that the splat-like Fe3O4/Au structure was in the range of 130 nm and homogeneously distributed in the aqueous medium. The nanocomposites were incubated with MCF-7 cells to investigate the magnetic resonance imaging (MRI) and surface-enhanced Raman scattering (SERS) activities. The excellent T2 MRI and enhanced SERS properties were obtained without any cytotoxicity. These results demonstrated that assynthesized splat-shaped Fe3O4/Au nanocomposites may be a promising MRI/SERS dual probe for the tumor detection.
The development of multifunctional contrast agents contributes significant character in the diagnosis of cancer. However, still efforts are required to design and improve the biocompatibility of contrast agents for early detection of cancer. Herein, we synthesized splat shape Fe3O4/Au nanocomposites for multimode biomedical applications. Transmission electron microscopy (TEM) results showed that the splat-like Fe3O4/Au structure was in the range of 130 nm and homogeneously distributed in the aqueous medium. The nanocomposites were incubated with MCF-7 cells to investigate the magnetic resonance imaging (MRI) and surface-enhanced Raman scattering (SERS) activities. The excellent T2 MRI and enhanced SERS properties were obtained without any cytotoxicity. These results demonstrated that assynthesized splat-shaped Fe3O4/Au nanocomposites may be a promising MRI/SERS dual probe for the tumor detection.
2019, 30(1): 90-94
doi: 10.1016/j.cclet.2017.11.019
Abstract:
In order to study the damage of ambient fine particulate matter (PM2.5) to organism in the environment, the method of urinary metabolomics was used to detect the potential endogenous metabolites and their related metabolic pathways to clarify the toxicity mechanisms. Particles of PM2.5 collected from the fibrous membrane were extracted ultrasonically and dissolved in physiological saline to prepare PM2.5 suspension. The solution of saline and fine particular matter was injected into the trachea of rats respectively. The rats were injected two times a week for four weeks. Samples of 24-h urine were collected at the 14th day after the end of exposure, and the ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was used for the metabolomics detection. Principal component analysis (PCA) was used to investigate the global metabolomic alterations and a clear separation in the scatter diagram were observed. 17 potential endogenous metablites were identified from urinary samples in rats by UPLC-Q-TOF-MS. The primary metabolism pathways involved pentose and glucuronate interconversions, starch and sucrose metabolism, tryptophan metabolism, tyrosine metabolism, phenylalanine metabolism, purine metabolism, acetaminophen metabolism pathway, retinol metabolism and valproic acid metabolism pathway. The results are helpful to understand the toxicological mechanisms of PM2.5 and screened out potential biomarkers of rats which exposure to PM2.5.
In order to study the damage of ambient fine particulate matter (PM2.5) to organism in the environment, the method of urinary metabolomics was used to detect the potential endogenous metabolites and their related metabolic pathways to clarify the toxicity mechanisms. Particles of PM2.5 collected from the fibrous membrane were extracted ultrasonically and dissolved in physiological saline to prepare PM2.5 suspension. The solution of saline and fine particular matter was injected into the trachea of rats respectively. The rats were injected two times a week for four weeks. Samples of 24-h urine were collected at the 14th day after the end of exposure, and the ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was used for the metabolomics detection. Principal component analysis (PCA) was used to investigate the global metabolomic alterations and a clear separation in the scatter diagram were observed. 17 potential endogenous metablites were identified from urinary samples in rats by UPLC-Q-TOF-MS. The primary metabolism pathways involved pentose and glucuronate interconversions, starch and sucrose metabolism, tryptophan metabolism, tyrosine metabolism, phenylalanine metabolism, purine metabolism, acetaminophen metabolism pathway, retinol metabolism and valproic acid metabolism pathway. The results are helpful to understand the toxicological mechanisms of PM2.5 and screened out potential biomarkers of rats which exposure to PM2.5.
2019, 30(1): 95-98
doi: 10.1016/j.cclet.2018.01.048
Abstract:
The performance of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) is frequently compromised by the high limited of detection, heterogeneous distribution of matrix and analyte deposits and time-consuming drying time during the conventional drop drying procedure. Here, we describe a method based on membrane separation technology to assist in the drying of nanomaterials to rapidly make homogeneous sample spots and to enhance the mass signal. We demonstrate that the sample can be dried evenly in a few seconds and MS signal can be greatly optimized by using membrane separation technology. Enrichment with nanomaterials greatly enhances analyte signal strength while membrane separation method avoids the time-consuming requirements of searching for "sweet spots".
The performance of matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) is frequently compromised by the high limited of detection, heterogeneous distribution of matrix and analyte deposits and time-consuming drying time during the conventional drop drying procedure. Here, we describe a method based on membrane separation technology to assist in the drying of nanomaterials to rapidly make homogeneous sample spots and to enhance the mass signal. We demonstrate that the sample can be dried evenly in a few seconds and MS signal can be greatly optimized by using membrane separation technology. Enrichment with nanomaterials greatly enhances analyte signal strength while membrane separation method avoids the time-consuming requirements of searching for "sweet spots".
2019, 30(1): 123-126
doi: 10.1016/j.cclet.2018.07.001
Abstract:
An amphiphilic tetrathiafulvalene molecule was designed and readily synthesized. The am-TTF can gelate a variety of organic solvents in view of multiple intermolecular interactions, especially in polar solvent. SEM observation provided clear evidence for the self-assembled micro/nanofibers morphologies in gelation state. Moreover, XRD measurements indicated the formation of highly-ordered columnar structures. The FT-IR spectra revealed that the formation of mixed-valence states with the absorption over 1700 cm-1, showing the semiconductive behaviors with the conductivity of 10-4 S/cm. The am-TTF based conducting fibers could be promising candidates for organic electronics.
An amphiphilic tetrathiafulvalene molecule was designed and readily synthesized. The am-TTF can gelate a variety of organic solvents in view of multiple intermolecular interactions, especially in polar solvent. SEM observation provided clear evidence for the self-assembled micro/nanofibers morphologies in gelation state. Moreover, XRD measurements indicated the formation of highly-ordered columnar structures. The FT-IR spectra revealed that the formation of mixed-valence states with the absorption over 1700 cm-1, showing the semiconductive behaviors with the conductivity of 10-4 S/cm. The am-TTF based conducting fibers could be promising candidates for organic electronics.
2019, 30(1): 127-130
doi: 10.1016/j.cclet.2018.10.016
Abstract:
The cooperative electrostatic attraction and π-π aromatic stacking interactions between tetrahedral tetrapyridinium TP and three tetraanionic tetraphenylethylene derivatives TPE-1~3 led to the formation of a new kind of supramolecular polymer networks in water, which have been confirmed by 1H NMR, fluorescence, isothermal titration calorimetric (ITC) and dynamic light scattering (DLS) experiments. ITC studies show that the contributions of enthalpy and entropy were comparable, reflecting the importance of hydrophobicity in driving the intermolecular aromatic stacking. DLS experiments indicate that the linear supramolecular polymers formed by these tetratopic monomers further aggregated into networks of 102-nm size.
The cooperative electrostatic attraction and π-π aromatic stacking interactions between tetrahedral tetrapyridinium TP and three tetraanionic tetraphenylethylene derivatives TPE-1~3 led to the formation of a new kind of supramolecular polymer networks in water, which have been confirmed by 1H NMR, fluorescence, isothermal titration calorimetric (ITC) and dynamic light scattering (DLS) experiments. ITC studies show that the contributions of enthalpy and entropy were comparable, reflecting the importance of hydrophobicity in driving the intermolecular aromatic stacking. DLS experiments indicate that the linear supramolecular polymers formed by these tetratopic monomers further aggregated into networks of 102-nm size.
Facile construction of Zn(Ⅱ)-porphyrin-cored [5]rotaxane and its controllable aggregation behaviours
2019, 30(1): 131-134
doi: 10.1016/j.cclet.2018.10.035
Abstract:
Rotaxanes have attracted more and more attentions because of their diverse applications as sensors, catalysts, and functional materials. The construction of highly ordered and discrete multirotaxanes with the well-defined structure remains a challenge. Herein, a symmetric [5]rotaxane with zinc porphyrin as core and the neutral platinum-acetylide as the linkage was synthesized with high yield. The [5]rotaxane was well characterized with NMR spectroscopy and MALDI-TOF mass spectrometry. Interestingly, it was found that the [5]rotaxane showed the controllable aggregation behaviours in different solution compositions. For example, in non-polar solution, the [5]rotaxane could self-assemble into the largescaled solid nanospheres while the nanofibers were formed in polar solvent. Further investigation revealed that the [5]rotaxane displayed J-type aggregation in solution driven by π-π interaction. Notably, the similar structure without DPP[5]A formed the irregular morphology at the same condition, suggesting that the existence of rotaxanes endowed the complex with a relative rigid structure to facilitate the formation of the ordered aggregates.
Rotaxanes have attracted more and more attentions because of their diverse applications as sensors, catalysts, and functional materials. The construction of highly ordered and discrete multirotaxanes with the well-defined structure remains a challenge. Herein, a symmetric [5]rotaxane with zinc porphyrin as core and the neutral platinum-acetylide as the linkage was synthesized with high yield. The [5]rotaxane was well characterized with NMR spectroscopy and MALDI-TOF mass spectrometry. Interestingly, it was found that the [5]rotaxane showed the controllable aggregation behaviours in different solution compositions. For example, in non-polar solution, the [5]rotaxane could self-assemble into the largescaled solid nanospheres while the nanofibers were formed in polar solvent. Further investigation revealed that the [5]rotaxane displayed J-type aggregation in solution driven by π-π interaction. Notably, the similar structure without DPP[5]A formed the irregular morphology at the same condition, suggesting that the existence of rotaxanes endowed the complex with a relative rigid structure to facilitate the formation of the ordered aggregates.
2019, 30(1): 135-138
doi: 10.1016/j.cclet.2018.09.007
Abstract:
Polymer thin film with uniform thickness and flat surface profile is the key point for polymer light emitting diodes (PLEDs) by inkjet printing. However, the coffee ring effect is usually observed due to the mismatch between the evaporation of the solvent and the decrease of solution volume, which promotes the formation of radial flow from the interior of the drop to the edge. In this paper, coffee ring effects of inkjet printed poly(spirobifluorene) films were proposed to be restrained by decreasing capillary force by adding co-solvent with high boiling point and high viscosity to the main solvent. The low evaporation rate of the co-solvent can reduce the driving force of the radial flow; meanwhile the high viscosity of the co-solvent can increase the resistance of the radial flow. Thus, polymer films with improve uniformity can be obtained due to the suppression of the radial flow. The device performance was greatly improved under the condition of proper film thickness and film uniformity and the maximum luminous efficiency of devices with inkjet printed poly(spirobifluorene) can reach 80% of the spin-coated devices.
Polymer thin film with uniform thickness and flat surface profile is the key point for polymer light emitting diodes (PLEDs) by inkjet printing. However, the coffee ring effect is usually observed due to the mismatch between the evaporation of the solvent and the decrease of solution volume, which promotes the formation of radial flow from the interior of the drop to the edge. In this paper, coffee ring effects of inkjet printed poly(spirobifluorene) films were proposed to be restrained by decreasing capillary force by adding co-solvent with high boiling point and high viscosity to the main solvent. The low evaporation rate of the co-solvent can reduce the driving force of the radial flow; meanwhile the high viscosity of the co-solvent can increase the resistance of the radial flow. Thus, polymer films with improve uniformity can be obtained due to the suppression of the radial flow. The device performance was greatly improved under the condition of proper film thickness and film uniformity and the maximum luminous efficiency of devices with inkjet printed poly(spirobifluorene) can reach 80% of the spin-coated devices.
2019, 30(1): 139-142
doi: 10.1016/j.cclet.2018.01.008
Abstract:
Chiral mesoporous silica ribbons and rods with inversed handedness have been synthesized with the same enantio pure N-acylaminoacidat temperatures of 0¦ and 20¦, respectively. With involving Cu2+ and meso-tetra(4-sulfonatophenyl) porphyrin (TPPS) as probes, ribbons and rods revealed opposite signals in diffuse-reflectance circular dichroism (DRCD) spectra, indicating the existence of inversed supramolecular chiral imprintings through helical stacking of amphiphiles. The structural evolution was systematically studied by the freeze-dried products sampled at different time after the addition of silica precursors. The H-bonding-depended molecular orientation probably controls the chiral sense upon forming chiral molecular stacking, which would be the origin of such handedness inversion phenomenon
Chiral mesoporous silica ribbons and rods with inversed handedness have been synthesized with the same enantio pure N-acylaminoacidat temperatures of 0¦ and 20¦, respectively. With involving Cu2+ and meso-tetra(4-sulfonatophenyl) porphyrin (TPPS) as probes, ribbons and rods revealed opposite signals in diffuse-reflectance circular dichroism (DRCD) spectra, indicating the existence of inversed supramolecular chiral imprintings through helical stacking of amphiphiles. The structural evolution was systematically studied by the freeze-dried products sampled at different time after the addition of silica precursors. The H-bonding-depended molecular orientation probably controls the chiral sense upon forming chiral molecular stacking, which would be the origin of such handedness inversion phenomenon
2019, 30(1): 149-152
doi: 10.1016/j.cclet.2018.04.035
Abstract:
Polyamide/acrylonitrile-butadiene-styrene copolymer (PA/ABS) blends have drawn considerable attention from both academia and industry for their important applications in automotive and electronic areas. Due to poor miscibility of PA and ABS, developing an effective compatibilization strategy has been an urgent challenge to achieve prominent mechanical properties. In this study, we create a set of mechanically enhanced PA6/ABS blends using two multi-monomer melt-grafted compatibilizers, SEBSg-(MAH-co-St) and ABS-g-(MAH-co-St). The dispersed domain size is significantly decreased and meanwhile the unique "soft shell-encapsulating-hard core" structures form in the presence of compatibilizers. The optimum mechanical performances manifest an increase of 36% in tensile strength and an increase of 1300% in impact strength, compared with the neat PA6/ABS binary blend.
Polyamide/acrylonitrile-butadiene-styrene copolymer (PA/ABS) blends have drawn considerable attention from both academia and industry for their important applications in automotive and electronic areas. Due to poor miscibility of PA and ABS, developing an effective compatibilization strategy has been an urgent challenge to achieve prominent mechanical properties. In this study, we create a set of mechanically enhanced PA6/ABS blends using two multi-monomer melt-grafted compatibilizers, SEBSg-(MAH-co-St) and ABS-g-(MAH-co-St). The dispersed domain size is significantly decreased and meanwhile the unique "soft shell-encapsulating-hard core" structures form in the presence of compatibilizers. The optimum mechanical performances manifest an increase of 36% in tensile strength and an increase of 1300% in impact strength, compared with the neat PA6/ABS binary blend.
2019, 30(1): 153-156
doi: 10.1016/j.cclet.2018.03.002
Abstract:
A new allylnickel(Ⅱ) complex ([S(R)]-N-[(1S)-2-(diphenylphosphino)-1-phenylethyl]-2-methyl-2-propanesulfinamide)(2, 2, 2-trifluoroacetato-κO)(π-allyl) nickel (2) was designed and prepared by using chiral phosphine. 2 was revealed to efficiently initiate the polymerization of L-and D-N-(1-(dodecylamino)-1-oxopropan-2-yl)-4-(propa-1, 2-dien-1-yloxy)-benzamide (L-1 and D-1) in a living/controlled chain growth manner. Polymerization kinetics of L-1 and D-1 indicated that L-1 preferentially polymerized over the antipode D-1 by a factor of 1.9. In block copolymerization of rac-1 using the poly-L-150 as the macroinitiator, the polymerization proceeded in enantiomer-selective manner. It was found that enantiomeric excess (ee) value of the recovered monomer increased with the monomer conversion and finally reached to the maximum of 34%. These results suggest this chiral phosphine complex exhibits enantiomer-selectivity for the polymerization of chiral allene derivative monomer.
A new allylnickel(Ⅱ) complex ([S(R)]-N-[(1S)-2-(diphenylphosphino)-1-phenylethyl]-2-methyl-2-propanesulfinamide)(2, 2, 2-trifluoroacetato-κO)(π-allyl) nickel (2) was designed and prepared by using chiral phosphine. 2 was revealed to efficiently initiate the polymerization of L-and D-N-(1-(dodecylamino)-1-oxopropan-2-yl)-4-(propa-1, 2-dien-1-yloxy)-benzamide (L-1 and D-1) in a living/controlled chain growth manner. Polymerization kinetics of L-1 and D-1 indicated that L-1 preferentially polymerized over the antipode D-1 by a factor of 1.9. In block copolymerization of rac-1 using the poly-L-150 as the macroinitiator, the polymerization proceeded in enantiomer-selective manner. It was found that enantiomeric excess (ee) value of the recovered monomer increased with the monomer conversion and finally reached to the maximum of 34%. These results suggest this chiral phosphine complex exhibits enantiomer-selectivity for the polymerization of chiral allene derivative monomer.
2019, 30(1): 157-159
doi: 10.1016/j.cclet.2018.01.037
Abstract:
Polystyrene (PS) fibers with core-shell structures were fabricated by coaxial electrostatic spinning, in which there are liquid epoxy or curing agent as the core and PS as the shell. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra and optical microscope were utilized for charactering the morphology and composition of the fibers. Composite coatings embedded with the healant-loaded coreshell fibers have been prepared and the self-healing of the scratch on the coatings has been revealed.
Polystyrene (PS) fibers with core-shell structures were fabricated by coaxial electrostatic spinning, in which there are liquid epoxy or curing agent as the core and PS as the shell. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra and optical microscope were utilized for charactering the morphology and composition of the fibers. Composite coatings embedded with the healant-loaded coreshell fibers have been prepared and the self-healing of the scratch on the coatings has been revealed.
2019, 30(1): 160-162
doi: 10.1016/j.cclet.2018.07.011
Abstract:
A new α-fetoprotein-MIP (AFP-MIP) immunosensor based on glass carbon electrode (GCE) modified with polythionine (PTh) and gold nanoparticles (AuNPs) was successfully fabricated for sensitive detection of α-fetoprotein (AFP). Through controlling electropolymerization, A "polydopamine (PDA)-AFP" complex was achieved applying AFP as template and dopamine (DA) as imprinted monomers. After elution, the specific cavities can adsorb the target molecules. Using differential pulse voltammetry (DPV) detection, the peak current decreased with the increase in concentration of AFP, and the linear response range of the AFP-MIP immunosensor was from 0.001 ng/mL to 800 ng/mL with the detection limit as low as 0.8138 pg/mL. The MIP immunosensor could become a new promising method for the detection of AFP. Furthermore, this MIP sensor was demonstrated in testing AFP in human serum samples with satisfactory results.
A new α-fetoprotein-MIP (AFP-MIP) immunosensor based on glass carbon electrode (GCE) modified with polythionine (PTh) and gold nanoparticles (AuNPs) was successfully fabricated for sensitive detection of α-fetoprotein (AFP). Through controlling electropolymerization, A "polydopamine (PDA)-AFP" complex was achieved applying AFP as template and dopamine (DA) as imprinted monomers. After elution, the specific cavities can adsorb the target molecules. Using differential pulse voltammetry (DPV) detection, the peak current decreased with the increase in concentration of AFP, and the linear response range of the AFP-MIP immunosensor was from 0.001 ng/mL to 800 ng/mL with the detection limit as low as 0.8138 pg/mL. The MIP immunosensor could become a new promising method for the detection of AFP. Furthermore, this MIP sensor was demonstrated in testing AFP in human serum samples with satisfactory results.
2019, 30(1): 163-166
doi: 10.1016/j.cclet.2017.12.012
Abstract:
This paper presented an interesting nanoparticle-based drug delivery system with morphology transition behavior depending on the content of exposed PEG chain on the particle surface, which is adjustable by addition of different amount of cyclodextrin (α-CD). The effect of α-CD inclusion to the self-assembly behavior of methoxy polyethylene glycol (mPEG) grafted chitosan (CS) was studied. The results showed that the mPEG grafted chitosan (mPEG-g-CS) forms self-assembled nanoparticles with either micelle or hollow sphere morphology depending on the ratio of α-CD to mPEG, as characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Their sizes and zeta potential increased from 257.6 nmto 768.2 nm and from +4.5 mV to +11.6 mV, respectively, with the increasing amount of α-CD. The correlation between zeta potential and particle size of α-CD/mPEG-g-CS nanoparticles indicated varied PEG density on surface of nanoparticles. Based on the above experimental observations, a likely mechanism for the morphological transition of the rod-coil graft copolymer mPEG-g-CS was proposed.
This paper presented an interesting nanoparticle-based drug delivery system with morphology transition behavior depending on the content of exposed PEG chain on the particle surface, which is adjustable by addition of different amount of cyclodextrin (α-CD). The effect of α-CD inclusion to the self-assembly behavior of methoxy polyethylene glycol (mPEG) grafted chitosan (CS) was studied. The results showed that the mPEG grafted chitosan (mPEG-g-CS) forms self-assembled nanoparticles with either micelle or hollow sphere morphology depending on the ratio of α-CD to mPEG, as characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Their sizes and zeta potential increased from 257.6 nmto 768.2 nm and from +4.5 mV to +11.6 mV, respectively, with the increasing amount of α-CD. The correlation between zeta potential and particle size of α-CD/mPEG-g-CS nanoparticles indicated varied PEG density on surface of nanoparticles. Based on the above experimental observations, a likely mechanism for the morphological transition of the rod-coil graft copolymer mPEG-g-CS was proposed.
2019, 30(1): 167-170
doi: 10.1016/j.cclet.2018.01.049
Abstract:
Au nanoparticles (AuNPs) were electrodeposited at the highly ordered anatase TiO2 nanotube array (TiO2NA) electrode under sonicating, and the AuNP-TiO2NA sensor was characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD). The photoelectrochemical experiments indicate the AuNP-TiO2NA sensor has lower photoelectro-resistance, higher photoelectrocatalytical activity and stability than that of pure TiO2NA sensor under the same conditions. The as-prepared sensor can be used for the determination of chemical oxygen demand (COD) in real samples, and the obtained results are comparable well with those of by standard K2Cr2O7 method. The method proposed is simple, fast, cost effective, and environmentally friendly.
Au nanoparticles (AuNPs) were electrodeposited at the highly ordered anatase TiO2 nanotube array (TiO2NA) electrode under sonicating, and the AuNP-TiO2NA sensor was characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD). The photoelectrochemical experiments indicate the AuNP-TiO2NA sensor has lower photoelectro-resistance, higher photoelectrocatalytical activity and stability than that of pure TiO2NA sensor under the same conditions. The as-prepared sensor can be used for the determination of chemical oxygen demand (COD) in real samples, and the obtained results are comparable well with those of by standard K2Cr2O7 method. The method proposed is simple, fast, cost effective, and environmentally friendly.
2019, 30(1): 171-174
doi: 10.1016/j.cclet.2018.03.001
Abstract:
A facile green low-cost controllable hydrothermal-thermal conversion (HTC) process for the uniform high aspect ratio CaSiO3 nanowires has been developed using abundant CaCl2·2H2O and Na2SiO3·9H2O as raw materials without any organic additive. The nanowires exhibited a transparent characteristic from the ultraviolet to visible region, and the CaSiO3:1.2%Tb3+ nanophosphors with well preserved 1D morphology demonstrated strong green luminescence with CIE coordinates of (x=0.3144, y=0.5912). The present work definitely reveals the nanowires as a promising structure and function integrated host candidate for green-emitting luminescent materials in light display systems and optoelectronic devices.
A facile green low-cost controllable hydrothermal-thermal conversion (HTC) process for the uniform high aspect ratio CaSiO3 nanowires has been developed using abundant CaCl2·2H2O and Na2SiO3·9H2O as raw materials without any organic additive. The nanowires exhibited a transparent characteristic from the ultraviolet to visible region, and the CaSiO3:1.2%Tb3+ nanophosphors with well preserved 1D morphology demonstrated strong green luminescence with CIE coordinates of (x=0.3144, y=0.5912). The present work definitely reveals the nanowires as a promising structure and function integrated host candidate for green-emitting luminescent materials in light display systems and optoelectronic devices.
2019, 30(1): 175-178
doi: 10.1016/j.cclet.2018.04.020
Abstract:
Herein we demonstrate the construction of three types of parallel gold nanorod (AuNR) clusters using a DNA origami rod (DOR) as the template. Based on the precise control over the position of capture strands on DOR, number and orientation of the AuNR clusters can be well engineered, as evidenced by biological transmission electron microscope (TEM). Importantly, the AuNR clusters exhibit chiroptical responses which are strongly affected by the number of AuNR on rod-like DNA origami.
Herein we demonstrate the construction of three types of parallel gold nanorod (AuNR) clusters using a DNA origami rod (DOR) as the template. Based on the precise control over the position of capture strands on DOR, number and orientation of the AuNR clusters can be well engineered, as evidenced by biological transmission electron microscope (TEM). Importantly, the AuNR clusters exhibit chiroptical responses which are strongly affected by the number of AuNR on rod-like DNA origami.
2019, 30(1): 179-182
doi: 10.1016/j.cclet.2018.06.013
Abstract:
Creating hotspots with significantly enhanced electromagnetic (EF) field, efficiently placing target molecules in hotspot region, and achieving uniform and reproducible Raman signals are three critical issues for developing high-performance SERS substrates. In this work, large area gold nanoparticle cluster pillar array with a gold mirror at bottom was facilely fabricated by combined use of nanosphere lithography and self-assembly approach. It is both theoretically and experimentally found that through multiple coupling interactions, the electromagnetic fields at interparticle gaps within the gold clusters were significantly enhanced in our three-dimentional (3D) pillar array substrates, which can result in one order of magnitude stronger as compared with random gold clusters on a two-dimentional planar case. Due to the periodic stucture, our substrates also possess the capbility of producing highly uniform and reproducible SERS signals. Attractively, in our case, a photoresponsive polymer was used for the formation of pillar array structure. Its unique photoinduced deformation makes it possible to reversibly open and close the gaps of the closely packed Au NP array, thus enabling efficient placement or entrapment of probe molecules into hotspot sites between adjacent nanoparticles.
Creating hotspots with significantly enhanced electromagnetic (EF) field, efficiently placing target molecules in hotspot region, and achieving uniform and reproducible Raman signals are three critical issues for developing high-performance SERS substrates. In this work, large area gold nanoparticle cluster pillar array with a gold mirror at bottom was facilely fabricated by combined use of nanosphere lithography and self-assembly approach. It is both theoretically and experimentally found that through multiple coupling interactions, the electromagnetic fields at interparticle gaps within the gold clusters were significantly enhanced in our three-dimentional (3D) pillar array substrates, which can result in one order of magnitude stronger as compared with random gold clusters on a two-dimentional planar case. Due to the periodic stucture, our substrates also possess the capbility of producing highly uniform and reproducible SERS signals. Attractively, in our case, a photoresponsive polymer was used for the formation of pillar array structure. Its unique photoinduced deformation makes it possible to reversibly open and close the gaps of the closely packed Au NP array, thus enabling efficient placement or entrapment of probe molecules into hotspot sites between adjacent nanoparticles.
2019, 30(1): 183-186
doi: 10.1016/j.cclet.2018.04.034
Abstract:
β-FeOOH nanorods were prepared by a poly ethylene glycol (PEG) assisted precipitation of FeCl3·6H2O aqueous solution with urea. Na2CO3 aqueous solution was introduced to maintain their shapes under annealing. The one-dimensional porous iron oxide nanorods were synthesized successfully. The asprepared catalysts were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms and X-ray photoelectron spectroscopy. The hydrogenation of nitrobenzene to aniline was taken as probe reaction to evaluate their catalytic performance. FeOOH (iron oxides hydroxide) nanorods, fabricated by annealing β-FeOOH nanorods at 250 ℃ in Ar atmosphere for 4 h, exhibited high catalytic activity for the transfer hydrogenation of nitrobenzene to aniline with hydrazine hydrate as hydrogen donors.
β-FeOOH nanorods were prepared by a poly ethylene glycol (PEG) assisted precipitation of FeCl3·6H2O aqueous solution with urea. Na2CO3 aqueous solution was introduced to maintain their shapes under annealing. The one-dimensional porous iron oxide nanorods were synthesized successfully. The asprepared catalysts were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms and X-ray photoelectron spectroscopy. The hydrogenation of nitrobenzene to aniline was taken as probe reaction to evaluate their catalytic performance. FeOOH (iron oxides hydroxide) nanorods, fabricated by annealing β-FeOOH nanorods at 250 ℃ in Ar atmosphere for 4 h, exhibited high catalytic activity for the transfer hydrogenation of nitrobenzene to aniline with hydrazine hydrate as hydrogen donors.
2019, 30(1): 187-191
doi: 10.1016/j.cclet.2018.02.015
Abstract:
We developed one-pot photoreduction strategy to prepare near infrared light (NIR)-absorbing plasmonic gold nanoparticles (Au NPs) tethered by amphiphilic polypeptide copolymer poly(L-cysteine)-b-poly (ethylene oxide) (PLC-b-PEO). The PLC-b-PEO@Au NPs possessed strong NIR absorption at 700-1100 nm and ultrahigh photothermal conversion efficiency of 62.1%. Upon the NIR irradiation (808 nm, 2 W/cm2, 5 min), the PLC-b-PEO@Au NPs (1 mg/mL) sharply attained an elevation of 30.8℃ and the hyperthermia effect could efficiently kill cancer cells in vitro. As for the PT-CT treatment, the doxorubicin (DOX)-loaded nanoparticles of DOX-PLC-b-PEO@Au NPs gave a combination index of 0.9 compared to single chemotherapy (CT) or photothermal therapy (PT), demonstrating a synergistic effect.
We developed one-pot photoreduction strategy to prepare near infrared light (NIR)-absorbing plasmonic gold nanoparticles (Au NPs) tethered by amphiphilic polypeptide copolymer poly(L-cysteine)-b-poly (ethylene oxide) (PLC-b-PEO). The PLC-b-PEO@Au NPs possessed strong NIR absorption at 700-1100 nm and ultrahigh photothermal conversion efficiency of 62.1%. Upon the NIR irradiation (808 nm, 2 W/cm2, 5 min), the PLC-b-PEO@Au NPs (1 mg/mL) sharply attained an elevation of 30.8℃ and the hyperthermia effect could efficiently kill cancer cells in vitro. As for the PT-CT treatment, the doxorubicin (DOX)-loaded nanoparticles of DOX-PLC-b-PEO@Au NPs gave a combination index of 0.9 compared to single chemotherapy (CT) or photothermal therapy (PT), demonstrating a synergistic effect.
2019, 30(1): 192-196
doi: 10.1016/j.cclet.2018.05.009
Abstract:
Molybdenum carbides (MoxC)/nitrogen doped carbon nanosheets (NCS) composites are synthesized via simple mixing melamine and ammonia molybdate, followed by a high-temperature treatment. Metal carbide nanoparticles with ultra-small size (13 nm) are uniformly supported on nitrogen doped carbon nanosheets. The hydrogen evolution reaction (HER) is investigated in both 0.5 mol/L H2SO4 and 1 mol/L KOH media. Mo2C/NCS-10 (melamine/ammonia molybdate weight ratio of 10:1) exhibits excellent performance with a low overpotential of 130 mV in 0.5 mol/L H2SO4 solution and 108 mV in 1 mol/L KOH solution at the current density of 10 mA/cm2. The better electrocatalytic activity could be ascribed to Ndoped carbon nanosheets, small particle size, mesoporous structure, and large specific surface area, which could provide the large electrochemical active surface area and facilitate mass transport.
Molybdenum carbides (MoxC)/nitrogen doped carbon nanosheets (NCS) composites are synthesized via simple mixing melamine and ammonia molybdate, followed by a high-temperature treatment. Metal carbide nanoparticles with ultra-small size (13 nm) are uniformly supported on nitrogen doped carbon nanosheets. The hydrogen evolution reaction (HER) is investigated in both 0.5 mol/L H2SO4 and 1 mol/L KOH media. Mo2C/NCS-10 (melamine/ammonia molybdate weight ratio of 10:1) exhibits excellent performance with a low overpotential of 130 mV in 0.5 mol/L H2SO4 solution and 108 mV in 1 mol/L KOH solution at the current density of 10 mA/cm2. The better electrocatalytic activity could be ascribed to Ndoped carbon nanosheets, small particle size, mesoporous structure, and large specific surface area, which could provide the large electrochemical active surface area and facilitate mass transport.
2019, 30(1): 197-202
doi: 10.1016/j.cclet.2018.10.007
Abstract:
Lignin is the most abundant and important macromolecule in organic matter and its yield is second only to cellulose. Lignin is abundant in source, low in price, and has a large number of active groups such as methoxy group and carboxyl group, so it has great utilization value. We used lignin as a carbon source to prepare porous carbon nanosphere (PCN) materials, and in-situ synthesized the MoS2 on its surface. The high specific surface area (~462.8 m2/g), large pore volume and good electron conductivity of the porous carbon scaffold facilitated the reversible electro-chemical reaction of S towards metallic Li, and thus the nano-hybrid showed a high specific energy and excellent cycle stability which still remained 520 mAh/g after 50 cycles.
Lignin is the most abundant and important macromolecule in organic matter and its yield is second only to cellulose. Lignin is abundant in source, low in price, and has a large number of active groups such as methoxy group and carboxyl group, so it has great utilization value. We used lignin as a carbon source to prepare porous carbon nanosphere (PCN) materials, and in-situ synthesized the MoS2 on its surface. The high specific surface area (~462.8 m2/g), large pore volume and good electron conductivity of the porous carbon scaffold facilitated the reversible electro-chemical reaction of S towards metallic Li, and thus the nano-hybrid showed a high specific energy and excellent cycle stability which still remained 520 mAh/g after 50 cycles.
2019, 30(1): 203-206
doi: 10.1016/j.cclet.2018.04.006
Abstract:
Azobenzene and its derivatives are key raw materials and it is an environmentally friendly method for the preparation of azobenzene by hydrogenative coupling of nitrobenzene. The development of nickel based catalyst for organic transformations is of importance because of its relatively low cost and toxicity. In this work, we found that ethylenediamine can enrich the electron state of Ni and make the azobenzene easily desorb from the surface of the catalyst, which inhibits the hydrogenation of azobenzene to aniline. The selectivity of azobenzene is greatly improved. When the ratio of Ni and ethylenediamine is 1:10, the yield of the azobenzene can reach 95.5%.
Azobenzene and its derivatives are key raw materials and it is an environmentally friendly method for the preparation of azobenzene by hydrogenative coupling of nitrobenzene. The development of nickel based catalyst for organic transformations is of importance because of its relatively low cost and toxicity. In this work, we found that ethylenediamine can enrich the electron state of Ni and make the azobenzene easily desorb from the surface of the catalyst, which inhibits the hydrogenation of azobenzene to aniline. The selectivity of azobenzene is greatly improved. When the ratio of Ni and ethylenediamine is 1:10, the yield of the azobenzene can reach 95.5%.
2019, 30(1): 207-210
doi: 10.1016/j.cclet.2018.01.041
Abstract:
First-principles calculations based on van der Waals (vdW) corrected density functional theory (DFT) are firstly employed to investigate the adsorption of methanol (CH3OH) gas molecule on pristine and Xdoped phosphorene (X=B, C, N and O). The CH3OH gas molecule is placed on the top of different phosphorene surfaces, the whole adsorption systems are fully optimized by using Vienna ab initio simulation package (VASP). The calculation results demonstrate that both pristine and heteroatomdoped phosphorene are sensitive to CH3OH gas molecule with a moderate adsorption energy and an excellent charge transfer. Among all the investigated adsorption configurations, CH3OH gas molecule is physically absorbed on pristine phosphorene and heteroatom-doped phosphorene. The N and O doping improve the adsorption of phosphorene with CH3OH gas molecule, while B and C doping are almost not beneficial compared to the pristine phosphorene. The results suggest that N-doped and O-doped phosphorene are ideal candidates used for CH3OH gas sensing.
First-principles calculations based on van der Waals (vdW) corrected density functional theory (DFT) are firstly employed to investigate the adsorption of methanol (CH3OH) gas molecule on pristine and Xdoped phosphorene (X=B, C, N and O). The CH3OH gas molecule is placed on the top of different phosphorene surfaces, the whole adsorption systems are fully optimized by using Vienna ab initio simulation package (VASP). The calculation results demonstrate that both pristine and heteroatomdoped phosphorene are sensitive to CH3OH gas molecule with a moderate adsorption energy and an excellent charge transfer. Among all the investigated adsorption configurations, CH3OH gas molecule is physically absorbed on pristine phosphorene and heteroatom-doped phosphorene. The N and O doping improve the adsorption of phosphorene with CH3OH gas molecule, while B and C doping are almost not beneficial compared to the pristine phosphorene. The results suggest that N-doped and O-doped phosphorene are ideal candidates used for CH3OH gas sensing.
2019, 30(1): 211-216
doi: 10.1016/j.cclet.2018.05.029
Abstract:
Organic solar cells based on acceptor-π-acceptor (A-π-A) electron acceptors have attracted intensive attention due to their increasing and record power conversion efficiencies. To date, almost all of the reported A-π-A electron acceptors are based on aromatic π structures. Here, we have investigated the impact of anti-aromatization of the π-bridges on the optoelectronic properties of A-π-A electron acceptors by (time-dependent) density functional theory. Our calculations show that besides the frontier molecular orbitals corresponding to the aromatic π-bridge based acceptors ("aromatic" acceptors), additional and unique occupied and unoccupied frontier orbitals are found for the acceptors based on the anti-aromatic π-bridges ("anti-aromatic" acceptors). Moreover, by tuning isomeric structures of the π-bridges (e.g., fusion orientations or linking positions of thiophene moieties), the optical excitation energies for the transition between the additional occupied and unoccupied levels turn to be close to or substantially lower with respect to those for the transition between the "aromatic" frontier orbitals. The optical absorption of the "anti-aromatic" acceptors is thus either stronger or broader than the "aromatic" acceptors. Finally, the reorganization energies for electron transport are tunable and dependent on the π-bridge structures. These results indicate a great potential of "anti-aromatic" electron acceptors in organic photovoltaics.
Organic solar cells based on acceptor-π-acceptor (A-π-A) electron acceptors have attracted intensive attention due to their increasing and record power conversion efficiencies. To date, almost all of the reported A-π-A electron acceptors are based on aromatic π structures. Here, we have investigated the impact of anti-aromatization of the π-bridges on the optoelectronic properties of A-π-A electron acceptors by (time-dependent) density functional theory. Our calculations show that besides the frontier molecular orbitals corresponding to the aromatic π-bridge based acceptors ("aromatic" acceptors), additional and unique occupied and unoccupied frontier orbitals are found for the acceptors based on the anti-aromatic π-bridges ("anti-aromatic" acceptors). Moreover, by tuning isomeric structures of the π-bridges (e.g., fusion orientations or linking positions of thiophene moieties), the optical excitation energies for the transition between the additional occupied and unoccupied levels turn to be close to or substantially lower with respect to those for the transition between the "aromatic" frontier orbitals. The optical absorption of the "anti-aromatic" acceptors is thus either stronger or broader than the "aromatic" acceptors. Finally, the reorganization energies for electron transport are tunable and dependent on the π-bridge structures. These results indicate a great potential of "anti-aromatic" electron acceptors in organic photovoltaics.
2019, 30(1): 217-221
doi: 10.1016/j.cclet.2018.04.001
Abstract:
Here we investigate processing additive-dependent photovoltaic performance and charge recombination in organic bulk heterojunction (BHJ) solar cells based on a polymeric donor of PBDB-T blended with a non-fullerene acceptor m-ITIC. We find that PBDB-T:m-ITIC solar cells exhibit good compatibilities with the utilized additives (DIO, CN, DPE, and NMP) in optimal conditions, can have a high charge dissociation probability approaching 100% (with DIO), leading to ultimate efficiency >11%. Regardless of additives, we observe a dominant 1st order monomolecular recombination with insignificant bi-molecular recombination or space-charge effects in these solar cells. Despite of impressive power conversion efficiency (PCE), it is of surprise that Shockley-Read-Hall recombination is identified to play a role in device operation. Thus, it points to the necessity to mitigate the influences of traps to further boost the efficiency in non-fullerene based organic solar cells.
Here we investigate processing additive-dependent photovoltaic performance and charge recombination in organic bulk heterojunction (BHJ) solar cells based on a polymeric donor of PBDB-T blended with a non-fullerene acceptor m-ITIC. We find that PBDB-T:m-ITIC solar cells exhibit good compatibilities with the utilized additives (DIO, CN, DPE, and NMP) in optimal conditions, can have a high charge dissociation probability approaching 100% (with DIO), leading to ultimate efficiency >11%. Regardless of additives, we observe a dominant 1st order monomolecular recombination with insignificant bi-molecular recombination or space-charge effects in these solar cells. Despite of impressive power conversion efficiency (PCE), it is of surprise that Shockley-Read-Hall recombination is identified to play a role in device operation. Thus, it points to the necessity to mitigate the influences of traps to further boost the efficiency in non-fullerene based organic solar cells.
2019, 30(1): 222-224
doi: 10.1016/j.cclet.2018.09.014
Abstract:
Two simple electron acceptors based on unfused bithiophene core and 1, 1-dicyanomethylene-3-indanone end group were easily prepared via three synthetic steps. These acceptors exhibited broad absorption in the range of 300 nm to 800 nm, aligned energy levels and high crystallinity. When combined with a wide band gap donor polymer in non-fullerene solar cells, an initial power conversion efficiency of 2.4% was achieved. The relatively low efficiencies were due to the large phase separation in blended thin films, which is originated from their high aggregation tendency in thin films. Our results suggest that these electron acceptors with unfused core are promising candidates for commercial application of solar cells due to the low cost starting materials and facile synthesis.
Two simple electron acceptors based on unfused bithiophene core and 1, 1-dicyanomethylene-3-indanone end group were easily prepared via three synthetic steps. These acceptors exhibited broad absorption in the range of 300 nm to 800 nm, aligned energy levels and high crystallinity. When combined with a wide band gap donor polymer in non-fullerene solar cells, an initial power conversion efficiency of 2.4% was achieved. The relatively low efficiencies were due to the large phase separation in blended thin films, which is originated from their high aggregation tendency in thin films. Our results suggest that these electron acceptors with unfused core are promising candidates for commercial application of solar cells due to the low cost starting materials and facile synthesis.
2019, 30(1): 225-228
doi: 10.1016/j.cclet.2018.05.003
Abstract:
Iodinated boron dipyrromethene (BODIPY) dyes with 8-hydroxyl-quinoline or phenylamine moiety at the meso-position on the BODIPY core were used as efficient photosensitizers (PSs) of three-component light-driven production of H2 system from acidic aqueous solution in conjunction with a cobaloxime[CoⅢ(dmgH)2PyCl] (dmgH=dimethylglyoximate, and py=pyridine) as proton-reducing catalyst and ascorbic acid (H2A) as sacrificial electron donor. This is the first example of BODIPYs as homogeneous hydrogen-generating PSs employed in the acidic aqueous conditions. That they are active in the acidic solutions and inactive in the basic conditions may indicate that the extent of competition between intramolecular and intermolecular electron transfer reactions exists. Efficient bimolecular electron transfer reaction between PS and molecular catalyst is needed to make H2 production, while the intramolecular electron transfer of PS may curb H2 production. The results underscore that the chemical modification of BODIPYs can be performed, thus allowing for the transformation of acid and base conditions for the light-driven H2 production.
Iodinated boron dipyrromethene (BODIPY) dyes with 8-hydroxyl-quinoline or phenylamine moiety at the meso-position on the BODIPY core were used as efficient photosensitizers (PSs) of three-component light-driven production of H2 system from acidic aqueous solution in conjunction with a cobaloxime[CoⅢ(dmgH)2PyCl] (dmgH=dimethylglyoximate, and py=pyridine) as proton-reducing catalyst and ascorbic acid (H2A) as sacrificial electron donor. This is the first example of BODIPYs as homogeneous hydrogen-generating PSs employed in the acidic aqueous conditions. That they are active in the acidic solutions and inactive in the basic conditions may indicate that the extent of competition between intramolecular and intermolecular electron transfer reactions exists. Efficient bimolecular electron transfer reaction between PS and molecular catalyst is needed to make H2 production, while the intramolecular electron transfer of PS may curb H2 production. The results underscore that the chemical modification of BODIPYs can be performed, thus allowing for the transformation of acid and base conditions for the light-driven H2 production.
2019, 30(1): 229-233
doi: 10.1016/j.cclet.2018.03.020
Abstract:
Developing active, robust, and cost-efficient electrocatalysts is critical for oxygen evolution reaction (OER). Here, a novel composite catalyst of Co1-xS embedded in porous dodecahedron carbon hybrid was synthesized by a two-step conversion protocol of a cobalt-based metal-organic framework (ZIF-67). The porous dodecahedron Co1-xS@C composite catalyst was prepared by direct oxidation of ZIF-67 followed by sulfurization reaction. The Co1-xS@C composite exhibit superior OER performance, including a low overpotential of 260 mV for 10 mA/cm2, a small Tafel slope of 85 mV/dec, outstanding stability over 80 h and almost 100% Faradaic efficiency. The various material characterizations indicate that the excellent activity and strong stability of Co1-xS@C might be attributed to good conductivity of Co1-xS, mesoporous nanostructure, and synergistic effect of Co1-xS encapsulated within porous carbon. This work provides a novel strategy for designing and synthesizing advanced composite electrocatalysts.
Developing active, robust, and cost-efficient electrocatalysts is critical for oxygen evolution reaction (OER). Here, a novel composite catalyst of Co1-xS embedded in porous dodecahedron carbon hybrid was synthesized by a two-step conversion protocol of a cobalt-based metal-organic framework (ZIF-67). The porous dodecahedron Co1-xS@C composite catalyst was prepared by direct oxidation of ZIF-67 followed by sulfurization reaction. The Co1-xS@C composite exhibit superior OER performance, including a low overpotential of 260 mV for 10 mA/cm2, a small Tafel slope of 85 mV/dec, outstanding stability over 80 h and almost 100% Faradaic efficiency. The various material characterizations indicate that the excellent activity and strong stability of Co1-xS@C might be attributed to good conductivity of Co1-xS, mesoporous nanostructure, and synergistic effect of Co1-xS encapsulated within porous carbon. This work provides a novel strategy for designing and synthesizing advanced composite electrocatalysts.
2019, 30(1): 234-238
doi: 10.1016/j.cclet.2018.03.023
Abstract:
In this paper, a new anionic metal-organic framework, [In(PBPTTBA)] [(CH3)2NH2] (BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4",4'"-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl)) tetrabenzoic acid (H4PBPTTBA) and In(NO3)2·5H2O and fully characterized by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), infrared spectroscopy (IR), and elemental analysis (EA). BUT-29 can be used as an efficient adsorbent for the selective removal of organic cationic dyes in N, N'-dimethylformamide (DMF) solution. The adsorption capacities of BUT-29 toward methylene blue and crystal violet at 298 K can reach 1119 mg/g and 832 mg/g, respectively. Moreover, the adsorbed dyes can be released in the DMF solution of LiNO3 gradually.
In this paper, a new anionic metal-organic framework, [In(PBPTTBA)] [(CH3)2NH2] (BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4",4'"-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl)) tetrabenzoic acid (H4PBPTTBA) and In(NO3)2·5H2O and fully characterized by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), infrared spectroscopy (IR), and elemental analysis (EA). BUT-29 can be used as an efficient adsorbent for the selective removal of organic cationic dyes in N, N'-dimethylformamide (DMF) solution. The adsorption capacities of BUT-29 toward methylene blue and crystal violet at 298 K can reach 1119 mg/g and 832 mg/g, respectively. Moreover, the adsorbed dyes can be released in the DMF solution of LiNO3 gradually.
2019, 30(1): 239-242
doi: 10.1016/j.cclet.2018.07.016
Abstract:
In this study, biologically inspired silk fibroin grafted polyacrylonitrile (SF-g-PAN) filtration membrane was prepared using ZnCl2 aqueous solution as solvent, avoiding the use of organic solvents. Phase inversion occurred when Zn2+ and Cl- ions gradually diffused into water, creating a well-connected ion channel network and the SF-g-PAN filtration membrane was obtained. The membranes were observed by SEM and 3D ultra-depth microscope. The hydrophilic property, pore size distribution and dye rejection of the membrane were investigated. Results showed that the membrane has no finger hole formation because ZnCl2 aqueous solution has a lower curing rate parameter compared with organic solvents. SF-g-PAN membrane possessed good anti-fouling properties and pH sensitivity. The pore size distribution of the SF-g-PAN membrane was 0.25-1.04 nm. The rejection of direct yellow 27 (Mw=662.6) and amaranth (Mw=604.5) was 96.51% and 30.63%, with the flux of 72.32 L m-2 h-1 and 73.83 L m-2 h-1 respectively at 0.1 MPa. The SF-g-PAN membrane has a wide range of applications prospect in fine separation, dye desalination, waste water treatment and biomedical fields.
In this study, biologically inspired silk fibroin grafted polyacrylonitrile (SF-g-PAN) filtration membrane was prepared using ZnCl2 aqueous solution as solvent, avoiding the use of organic solvents. Phase inversion occurred when Zn2+ and Cl- ions gradually diffused into water, creating a well-connected ion channel network and the SF-g-PAN filtration membrane was obtained. The membranes were observed by SEM and 3D ultra-depth microscope. The hydrophilic property, pore size distribution and dye rejection of the membrane were investigated. Results showed that the membrane has no finger hole formation because ZnCl2 aqueous solution has a lower curing rate parameter compared with organic solvents. SF-g-PAN membrane possessed good anti-fouling properties and pH sensitivity. The pore size distribution of the SF-g-PAN membrane was 0.25-1.04 nm. The rejection of direct yellow 27 (Mw=662.6) and amaranth (Mw=604.5) was 96.51% and 30.63%, with the flux of 72.32 L m-2 h-1 and 73.83 L m-2 h-1 respectively at 0.1 MPa. The SF-g-PAN membrane has a wide range of applications prospect in fine separation, dye desalination, waste water treatment and biomedical fields.
2019, 30(1): 243-246
doi: 10.1016/j.cclet.2018.04.010
Abstract:
Cisplatin is one of the most successful antitumor agents, yet also restricted by its poor cellular uptake and low selectivity. Since 3-(2-nitrophenyl) propionic acid (NPPA) has been reported as a bioreductive prodrug moiety, herein we combined NPPA with cisplatin (compound 1) to improve its lipophilicity and targetability and then to improve the antitumor outcomes. In addition, compound 2 possessing 3-phenyl propionic acid (PPA) was also synthesized as a comparison to test the influence of the NPPA to the cytotoxicity, since PPA was not a bioreductive moiety. Bioevaluations showed that 1 displayed more potent antitumor potency than cisplatin and 2, suggesting Pt(Ⅱ) complexes possessing NPPA groups may be a good strategy for future platinum drug discovery.
Cisplatin is one of the most successful antitumor agents, yet also restricted by its poor cellular uptake and low selectivity. Since 3-(2-nitrophenyl) propionic acid (NPPA) has been reported as a bioreductive prodrug moiety, herein we combined NPPA with cisplatin (compound 1) to improve its lipophilicity and targetability and then to improve the antitumor outcomes. In addition, compound 2 possessing 3-phenyl propionic acid (PPA) was also synthesized as a comparison to test the influence of the NPPA to the cytotoxicity, since PPA was not a bioreductive moiety. Bioevaluations showed that 1 displayed more potent antitumor potency than cisplatin and 2, suggesting Pt(Ⅱ) complexes possessing NPPA groups may be a good strategy for future platinum drug discovery.
2019, 30(1): 247-249
doi: 10.1016/j.cclet.2018.04.029
Abstract:
Eight new water-soluble amino acid conjugates 6a-h of chlorin p6 ethers (5a-d) were synthesized and preliminarily investigated for their in vitro PDT antitumor activity and structure-activity relationship (SAR). The results showed that all compounds exhibited much higher phototoxicity against tumor cells than talaporfin. SAR analysis indicated that PDT antitumor effect enhanced with the increase of carbon chain length of alkoxyl ether bonds at 31-position, and L-aspartic acid was superior to L-glutamic acid. In particular, the IC50 values of most phototoxic compound 6d were 0.20 mmol/L against A549 cell and 0.41 mmol/L against B16-F10 cell, which individually represented 31-and 24-fold increase of antitumor potency compared to talaporfin, suggesting that it was a promising candidate photosensitizer (PS) for PDT applications due to its strong absorption at long wavelength, high phototoxicity, low dark cytotoxicity and good water-solubility.
Eight new water-soluble amino acid conjugates 6a-h of chlorin p6 ethers (5a-d) were synthesized and preliminarily investigated for their in vitro PDT antitumor activity and structure-activity relationship (SAR). The results showed that all compounds exhibited much higher phototoxicity against tumor cells than talaporfin. SAR analysis indicated that PDT antitumor effect enhanced with the increase of carbon chain length of alkoxyl ether bonds at 31-position, and L-aspartic acid was superior to L-glutamic acid. In particular, the IC50 values of most phototoxic compound 6d were 0.20 mmol/L against A549 cell and 0.41 mmol/L against B16-F10 cell, which individually represented 31-and 24-fold increase of antitumor potency compared to talaporfin, suggesting that it was a promising candidate photosensitizer (PS) for PDT applications due to its strong absorption at long wavelength, high phototoxicity, low dark cytotoxicity and good water-solubility.
2019, 30(1): 250-254
doi: 10.1016/j.cclet.2017.11.041
Abstract:
Resistance to malaria parasites has quickly developed to almost all used antimalarial drugs. Cysteine protease falcipain-2 (FP-2) and Plasmodium falciparum dihydrofolate reductase (PfDHFR) have crucial roles, which are absolutely necessary, in the parasite life cycle. In this study, based on the uniform pharmacophores of reported PfDHFR inhibitors and the first-generation dual inhibitors against FP-2 and PfDHFR, we identified a novel series of dual inhibitors through fragments assembly. Lead optimization led to the identification of 14, which showed potent inhibition against FP-2 and PfDHFR enzyme (IC50=6.8±1.8 mmol/L and IC50=8.8±0.3 mmol/L) and P. falciparum 3D7 strain (IC50=2.9 mmol/L). Additionally, 14 exhibited more potent inhibition to the proliferation of chloroquine-resistant P. falciparum Dd2 strain (IC50=1.1 mmol/L) than pyrimethamine (IC50 >10 mmol/L), and 14 displayed micromolar inhibitory activities against two clinical isolated strains Fab9 (IC50=2.6 mmol/L) and GB4 (IC50=1.0 mmol/L). Collectively, these data demonstrated that 14 might be a good lead compound for the treatment of malaria.
Resistance to malaria parasites has quickly developed to almost all used antimalarial drugs. Cysteine protease falcipain-2 (FP-2) and Plasmodium falciparum dihydrofolate reductase (PfDHFR) have crucial roles, which are absolutely necessary, in the parasite life cycle. In this study, based on the uniform pharmacophores of reported PfDHFR inhibitors and the first-generation dual inhibitors against FP-2 and PfDHFR, we identified a novel series of dual inhibitors through fragments assembly. Lead optimization led to the identification of 14, which showed potent inhibition against FP-2 and PfDHFR enzyme (IC50=6.8±1.8 mmol/L and IC50=8.8±0.3 mmol/L) and P. falciparum 3D7 strain (IC50=2.9 mmol/L). Additionally, 14 exhibited more potent inhibition to the proliferation of chloroquine-resistant P. falciparum Dd2 strain (IC50=1.1 mmol/L) than pyrimethamine (IC50 >10 mmol/L), and 14 displayed micromolar inhibitory activities against two clinical isolated strains Fab9 (IC50=2.6 mmol/L) and GB4 (IC50=1.0 mmol/L). Collectively, these data demonstrated that 14 might be a good lead compound for the treatment of malaria.
2019, 30(1): 255-258
doi: 10.1016/j.cclet.2018.05.013
Abstract:
Water-bridged H-bonds have been observed in many cases of ligand-receptor recognitions. To explore the roles of water bridges in the binding of neonicotinoids with receptors, twenty-four neonicotinoid compounds with nine fragments, including 1H-1, 2, 3-triazole, CN, COOMe, CONHNH2, CONHMe, NO2, NH2, NHCOMe and NHCSNH2 were synthesized and evaluated, of which, compounds with cyano group showed the best activities against Aphis craccivora. Accordingly, the cyano group is the optimal fragment mimicking the water bridge. Two cyano-substituted cis-nitromethylene compounds display good insecticidal activities, whereas the LC50 values are lower than those of their corresponding prototypes. Docking study showed that the cyano group acts only as H-bond acceptor, while the water bridge can act as both donor and acceptor. It revealed that the water bridge might be stable in the active site and was not suitable to be replaced by other groups. The findings illustrated that the water bridge is necessary for high insecticidal activities of neonicotinoids, which should be also helpful in better understanding the binding mode of neonicotinoids.
Water-bridged H-bonds have been observed in many cases of ligand-receptor recognitions. To explore the roles of water bridges in the binding of neonicotinoids with receptors, twenty-four neonicotinoid compounds with nine fragments, including 1H-1, 2, 3-triazole, CN, COOMe, CONHNH2, CONHMe, NO2, NH2, NHCOMe and NHCSNH2 were synthesized and evaluated, of which, compounds with cyano group showed the best activities against Aphis craccivora. Accordingly, the cyano group is the optimal fragment mimicking the water bridge. Two cyano-substituted cis-nitromethylene compounds display good insecticidal activities, whereas the LC50 values are lower than those of their corresponding prototypes. Docking study showed that the cyano group acts only as H-bond acceptor, while the water bridge can act as both donor and acceptor. It revealed that the water bridge might be stable in the active site and was not suitable to be replaced by other groups. The findings illustrated that the water bridge is necessary for high insecticidal activities of neonicotinoids, which should be also helpful in better understanding the binding mode of neonicotinoids.
2019, 30(1): 259-262
doi: 10.1016/j.cclet.2018.01.033
Abstract:
A novel electron acceptor, namely, tetra-phthalimide end-fused bifluorenylidene (3D-imide) was designed and synthesized. In comparison to its framework analogue 12, 12'-bidibenzo[b, h]fluorenylidene (BF-3), the electron withdrawing capability and optical absorption were strengthened and enlarged, respectively. Moreover, photoluminescence quenching experiments were carried out, which confirmed 3D-imide could be a good candidate for nonfullene organic photovoltaics. Finally, we gained more insight into its electronic properties through density functional theory calculation.
A novel electron acceptor, namely, tetra-phthalimide end-fused bifluorenylidene (3D-imide) was designed and synthesized. In comparison to its framework analogue 12, 12'-bidibenzo[b, h]fluorenylidene (BF-3), the electron withdrawing capability and optical absorption were strengthened and enlarged, respectively. Moreover, photoluminescence quenching experiments were carried out, which confirmed 3D-imide could be a good candidate for nonfullene organic photovoltaics. Finally, we gained more insight into its electronic properties through density functional theory calculation.
2019, 30(1): 263-265
doi: 10.1016/j.cclet.2018.01.035
Abstract:
A synthetic method of dialkylideneacetones has been developed. Compared with known protocols, the method employed catalytic Ca(OH)2 as the cheap, mild base catalyst and dilute aqueous EtOH (20%, v/v) as the green and safe solvent. The procedure was easily operated:In most cases, the product could be isolated by a simple filtration, and purified by washing with water. This paper provided experimental details of the reactions, which could be applied in gram-scale synthesis and should be a very reliable and practical protocol to prepare these useful compounds in laboratory and at the industrial level.
A synthetic method of dialkylideneacetones has been developed. Compared with known protocols, the method employed catalytic Ca(OH)2 as the cheap, mild base catalyst and dilute aqueous EtOH (20%, v/v) as the green and safe solvent. The procedure was easily operated:In most cases, the product could be isolated by a simple filtration, and purified by washing with water. This paper provided experimental details of the reactions, which could be applied in gram-scale synthesis and should be a very reliable and practical protocol to prepare these useful compounds in laboratory and at the industrial level.
2019, 30(1): 266-268
doi: 10.1016/j.cclet.2018.05.040
Abstract:
A CuSO4 catalyzed ynamide formation/[4+2] cycloaddition relay reaction was achieved in one-pot. Various 4, 7-cis-dihydroindolines were produced in good to high yields. The one-pot operation in conjunction with the cheap and benign copper catalysis renders this reaction highly sustainable.
A CuSO4 catalyzed ynamide formation/[4+2] cycloaddition relay reaction was achieved in one-pot. Various 4, 7-cis-dihydroindolines were produced in good to high yields. The one-pot operation in conjunction with the cheap and benign copper catalysis renders this reaction highly sustainable.
2019, 30(1): 269-270
doi: 10.1016/j.cclet.2018.06.001
Abstract:
On the basis of the mild transformation of alkenyl triflates into alkynes promoted by LiCl, a one-pot protocol using alkenyl triflate precursors was developed for copper-mediated azide-alkyne cycloaddition. This protocol may provide an opportunity of sequentially click reactions for the construction of bifunctional probes in chemical biology studies.
On the basis of the mild transformation of alkenyl triflates into alkynes promoted by LiCl, a one-pot protocol using alkenyl triflate precursors was developed for copper-mediated azide-alkyne cycloaddition. This protocol may provide an opportunity of sequentially click reactions for the construction of bifunctional probes in chemical biology studies.
2019, 30(1): 120-122
doi: 10.1016/j.cclet.2018.04.028
Abstract:
The molecular assembling properties can be dramatically improved using redox-responsive nanoplatforms, which can bring quite different aggregation modes and binding behaviors in the redox states. In this work, we fabricated a redox-responsive system based on the host-guest complexation of β-cyclodextrin (β-CD) with ferrocene-modified diphenylalanine (Fc-FF). The morphological conversion of Fc-FF can be easily achieved from nanofibers to nanospheres in the presence of β-CD, and the supramolecular nanospheres can be reversibly assembled and disassembled by the chemical redox of ferrocenyl groups in the Fc-FF⊂β-CD nanoassemblies. These results demonstrate that the incorporation of stimuli-switchable components with macrocyclic receptors may become a promising approach to the construction of smart peptide-involved supramolecular assemblies.
The molecular assembling properties can be dramatically improved using redox-responsive nanoplatforms, which can bring quite different aggregation modes and binding behaviors in the redox states. In this work, we fabricated a redox-responsive system based on the host-guest complexation of β-cyclodextrin (β-CD) with ferrocene-modified diphenylalanine (Fc-FF). The morphological conversion of Fc-FF can be easily achieved from nanofibers to nanospheres in the presence of β-CD, and the supramolecular nanospheres can be reversibly assembled and disassembled by the chemical redox of ferrocenyl groups in the Fc-FF⊂β-CD nanoassemblies. These results demonstrate that the incorporation of stimuli-switchable components with macrocyclic receptors may become a promising approach to the construction of smart peptide-involved supramolecular assemblies.
2019, 30(1): 143-148
doi: 10.1016/j.cclet.2018.10.020
Abstract:
Tetraphenylporphyrin (TPP) is a typical red-emitting luminogen showing evident aggregation caused quenching (ACQ) effect. To enhance its emission efficiency in solid state, four tetraphenylethene (TPE) units were attached to the four meso-positions of TPP core via ester group through a facile and efficient route. The derived compound (4(TPE COO)-TPP) emits red fluorescence (peak at 655 nm) with a good quantum efficiency (Φ) of 7.5%, which is much higher than that of TPP (Φ~0.1%). In molecular aggregate formed in tetrahydrofuran (THF) and water mixtures, 4(TPE COO)-TPP has a relative high Φ of 12%. The evidently subdued ACQ behavior can be ascribed to the propeller shape and bulky size of the TPE units, which prevent the close packing and strong π-π interaction of TPP cores. The loose molecular packing and weak interchromophore interactions were validated by different characterization methods including UV-visible absorption, steady state and transient fluorescence spectroscope, X-ray diffraction and scanning electronic microscope observations. It is noted that 4(TPE COO)-TPP has an emission efficiency of 14.4% in dilute THF solution. This is due to the conjugation break between the TPP and TPE moieties, the rotational and vibrational motions of the phenyl groups cannot quench the fluorescence of 4(TPE COO)-TPP.
Tetraphenylporphyrin (TPP) is a typical red-emitting luminogen showing evident aggregation caused quenching (ACQ) effect. To enhance its emission efficiency in solid state, four tetraphenylethene (TPE) units were attached to the four meso-positions of TPP core via ester group through a facile and efficient route. The derived compound (4(TPE COO)-TPP) emits red fluorescence (peak at 655 nm) with a good quantum efficiency (Φ) of 7.5%, which is much higher than that of TPP (Φ~0.1%). In molecular aggregate formed in tetrahydrofuran (THF) and water mixtures, 4(TPE COO)-TPP has a relative high Φ of 12%. The evidently subdued ACQ behavior can be ascribed to the propeller shape and bulky size of the TPE units, which prevent the close packing and strong π-π interaction of TPP cores. The loose molecular packing and weak interchromophore interactions were validated by different characterization methods including UV-visible absorption, steady state and transient fluorescence spectroscope, X-ray diffraction and scanning electronic microscope observations. It is noted that 4(TPE COO)-TPP has an emission efficiency of 14.4% in dilute THF solution. This is due to the conjugation break between the TPP and TPE moieties, the rotational and vibrational motions of the phenyl groups cannot quench the fluorescence of 4(TPE COO)-TPP.
