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2019 Volume 30 Issue 7
2019, 30(7): 1353-1360
doi: 10.1016/j.cclet.2019.02.003
Abstract:
Near-infrared (NIR) fluorescent dyes based on small organic molecules are characterized with low cytotoxicity, good biocompatibility and minimum interference from auto-fluorescence background, which are widely used in tumor diagnosis. Intensive research on molecular properties and photothermal properties of fluorescent dyes have been explored for non-invasive photothermal treatment of cancer. In this review, we focus on the development of imaging-induced photothermal therapy of small molecules and classification according to the structures of organic molecules including cyanines, phthalocyanines, rhodamine analogues and BODIPYs.
Near-infrared (NIR) fluorescent dyes based on small organic molecules are characterized with low cytotoxicity, good biocompatibility and minimum interference from auto-fluorescence background, which are widely used in tumor diagnosis. Intensive research on molecular properties and photothermal properties of fluorescent dyes have been explored for non-invasive photothermal treatment of cancer. In this review, we focus on the development of imaging-induced photothermal therapy of small molecules and classification according to the structures of organic molecules including cyanines, phthalocyanines, rhodamine analogues and BODIPYs.
2019, 30(7): 1361-1368
doi: 10.1016/j.cclet.2019.03.034
Abstract:
1-Indenones are important scaffolds in natural products, biologically active molecules as well as functional materials. Recently, radical cascade cyclization has emerged as an efficient and powerful strategy for the construction of valuable and versatile functionalized 1-indenones. In this review, the recent advances of this rapidly growing area were summarized. The selected examples have been classified according to the type of reaction substrates such as 1, 3-diarylpropynones, 2-alkynylbenzonitriles, arylpropynols, 1, 5-enynes and 2-alkynylated bromocinnamates.
1-Indenones are important scaffolds in natural products, biologically active molecules as well as functional materials. Recently, radical cascade cyclization has emerged as an efficient and powerful strategy for the construction of valuable and versatile functionalized 1-indenones. In this review, the recent advances of this rapidly growing area were summarized. The selected examples have been classified according to the type of reaction substrates such as 1, 3-diarylpropynones, 2-alkynylbenzonitriles, arylpropynols, 1, 5-enynes and 2-alkynylated bromocinnamates.
2019, 30(7): 1369-1373
doi: 10.1016/j.cclet.2019.03.021
Abstract:
Venom toxins are widely spread in nature, adopting diverse structures and functions. They often function by blocking or modulating important membrane protein targets thus can be promising therapeutic candidates and biophysical probes. In this review, we briefly discuss the total chemical synthesis of venom toxins including the different refolding strategies reported during the past decade as well as innovative approaches for structure determination.
Venom toxins are widely spread in nature, adopting diverse structures and functions. They often function by blocking or modulating important membrane protein targets thus can be promising therapeutic candidates and biophysical probes. In this review, we briefly discuss the total chemical synthesis of venom toxins including the different refolding strategies reported during the past decade as well as innovative approaches for structure determination.
2019, 30(7): 1374-1378
doi: 10.1016/j.cclet.2019.01.033
Abstract:
Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C-H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.
Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C-H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.
2019, 30(7): 1379-1382
doi: 10.1016/j.cclet.2019.04.007
Abstract:
An interesting and recyclable activated carbon/water catalytic system for efficient synthesis of pyrrolo[1, 2-a]quinoxaline derivatives was developed. The intramolecular C-N and C-C bond can be easily constructed in water under mild condition. This reaction features a broad substrate scope, a good tolerance to water and air, metal-free, additive-free and redox reagent-free.
An interesting and recyclable activated carbon/water catalytic system for efficient synthesis of pyrrolo[1, 2-a]quinoxaline derivatives was developed. The intramolecular C-N and C-C bond can be easily constructed in water under mild condition. This reaction features a broad substrate scope, a good tolerance to water and air, metal-free, additive-free and redox reagent-free.
2019, 30(7): 1383-1386
doi: 10.1016/j.cclet.2019.03.056
Abstract:
Ru(bpy)3]2+-cored supramolecular organic framework SMOF-1, assembled from a [Ru(bpy)3]2+-derived hexaarmed molecule and cucurbit[8]uril, has been demonstrated to heterogeneously catalyze visible light-induced reduction of phenyl, benzyl, 2-phenylethyl and 3-phenylpropyl azides in acetonitrile to produce the corresponding amines in good to high yields. For the last two kinds of azides that bear a CO2Me group at the para-position of the benzene ring, cascade reactions take place to generate the corresponding lactams in high yields. Compared with homogeneous control [Ru(bpy)3]Cl2, SMOF-1 exhibits remarkably increased photocatalysis activity as a result of synergistic effect of the [Ru(bpy)3]2+ units that form cubic cages to host the azide molecules and related intermediates. Moreover, SMOF-1 displays high recyclability and considerable photocatalysis activity after 3 to 12 runs.
Ru(bpy)3]2+-cored supramolecular organic framework SMOF-1, assembled from a [Ru(bpy)3]2+-derived hexaarmed molecule and cucurbit[8]uril, has been demonstrated to heterogeneously catalyze visible light-induced reduction of phenyl, benzyl, 2-phenylethyl and 3-phenylpropyl azides in acetonitrile to produce the corresponding amines in good to high yields. For the last two kinds of azides that bear a CO2Me group at the para-position of the benzene ring, cascade reactions take place to generate the corresponding lactams in high yields. Compared with homogeneous control [Ru(bpy)3]Cl2, SMOF-1 exhibits remarkably increased photocatalysis activity as a result of synergistic effect of the [Ru(bpy)3]2+ units that form cubic cages to host the azide molecules and related intermediates. Moreover, SMOF-1 displays high recyclability and considerable photocatalysis activity after 3 to 12 runs.
2019, 30(7): 1387-1389
doi: 10.1016/j.cclet.2019.04.010
Abstract:
Pure organic room-temperature phosphorescence (RTP) materials have been attracting much attention recently. Herein, we report a facile approach combining heavy atom effect and external solvent stimuli to realize RTP. N-Allylquinolinium bromide under 365 nm UV exhibited intense green RTP emission with response upon adding chloroform. This interesting phenomenon endowed N-allylquinolinium bromide great potential as an anti-counterfeiting material.
Pure organic room-temperature phosphorescence (RTP) materials have been attracting much attention recently. Herein, we report a facile approach combining heavy atom effect and external solvent stimuli to realize RTP. N-Allylquinolinium bromide under 365 nm UV exhibited intense green RTP emission with response upon adding chloroform. This interesting phenomenon endowed N-allylquinolinium bromide great potential as an anti-counterfeiting material.
2019, 30(7): 1390-1392
doi: 10.1016/j.cclet.2019.03.007
Abstract:
Incorporation of guest ions into porous frameworks changed magnetism of the host materials significantly. However, in most cases, the guest ions were monovalent due to lack of reliable method to insert divalent and trivalent guest ions. In this work, we demonstrated that divalent and trivalent metal ions could be inserted into frameworks of a coordinate polymer, Cu3[Fe(CN)6]2, through electrochemical intercalation. The magnetism of the host frameworks was changed among paramagnetic, superparamagnetic, and ferromagnetic as demonstrated by physical property measurement system (PPMS). Furthermore, the magnetization of the frameworks under low temperatures correlated to the guest ions significantly. The ionic radius and net charge of the guest ions influenced the intercalation amount of the guest ions, therefore affected the valence change of Fe3+ ions in the host frameworks, finally leading to variation of the magnetism of the host materials.
Incorporation of guest ions into porous frameworks changed magnetism of the host materials significantly. However, in most cases, the guest ions were monovalent due to lack of reliable method to insert divalent and trivalent guest ions. In this work, we demonstrated that divalent and trivalent metal ions could be inserted into frameworks of a coordinate polymer, Cu3[Fe(CN)6]2, through electrochemical intercalation. The magnetism of the host frameworks was changed among paramagnetic, superparamagnetic, and ferromagnetic as demonstrated by physical property measurement system (PPMS). Furthermore, the magnetization of the frameworks under low temperatures correlated to the guest ions significantly. The ionic radius and net charge of the guest ions influenced the intercalation amount of the guest ions, therefore affected the valence change of Fe3+ ions in the host frameworks, finally leading to variation of the magnetism of the host materials.
2019, 30(7): 1393-1396
doi: 10.1016/j.cclet.2019.03.046
Abstract:
We designed a lysosome-selective Raman probe by conjugating bisphenylbutadiyne with morpholine, a well-known lysosome targeting moiety. This probe, named Lyso-BADY, has a Raman peak 28 times more intense than that of 5-ethynyl-2'-deoxyuridine. Lysosome in living cells was successfully visualized by hyperspectral stimulated Raman scattering (SRS) microscopy with this extracellular probe. Further study showed that the Raman signal of Lyso-BADY remained steady and strong even after a prolonged irradiation time. The photo-stability feature of Lyso-BADY rendered molecules of the similar structure as potentially versatile probe for continuous imaging in the future
We designed a lysosome-selective Raman probe by conjugating bisphenylbutadiyne with morpholine, a well-known lysosome targeting moiety. This probe, named Lyso-BADY, has a Raman peak 28 times more intense than that of 5-ethynyl-2'-deoxyuridine. Lysosome in living cells was successfully visualized by hyperspectral stimulated Raman scattering (SRS) microscopy with this extracellular probe. Further study showed that the Raman signal of Lyso-BADY remained steady and strong even after a prolonged irradiation time. The photo-stability feature of Lyso-BADY rendered molecules of the similar structure as potentially versatile probe for continuous imaging in the future
2019, 30(7): 1397-1400
doi: 10.1016/j.cclet.2019.04.003
Abstract:
Biomimetic nanodevice is an important branch to expand the potential applications of artificial nanochannels. Here, we constructed nanochannels for cascade response of borate and cis-hydroxyl compounds by modifying the nanochannels of track-etched polycarbonate (TEPC) membranes with polyvinyl alcohol (PVA). Firstly, borate bound to PVA and increased the negative charge density on the surface of the nanochannels, which obstructed the transport of 1, 5-naphthalene disulfonate (NDS2-). Subsequently, the addition of cis-hydroxyl compounds induced leaving of borate due to the stronger binding affinities between borate and cis-hydroxyl compounds, which reduced the negative charge density on nanochannels and then enhanced the transport of NDS2-. The cascade response of the nanochannels also accord with the properties of IMP (implication) logic gate. In addition, such nanochannels showed good reproducibility and reversibility. Therefore, this cascade response model based on nanochannels has the potential to be used as switches in area of actuators and biosensors, and is also expected to be used to understand the interaction of substances in nanoscale and simulate the physiological functions of boron.
Biomimetic nanodevice is an important branch to expand the potential applications of artificial nanochannels. Here, we constructed nanochannels for cascade response of borate and cis-hydroxyl compounds by modifying the nanochannels of track-etched polycarbonate (TEPC) membranes with polyvinyl alcohol (PVA). Firstly, borate bound to PVA and increased the negative charge density on the surface of the nanochannels, which obstructed the transport of 1, 5-naphthalene disulfonate (NDS2-). Subsequently, the addition of cis-hydroxyl compounds induced leaving of borate due to the stronger binding affinities between borate and cis-hydroxyl compounds, which reduced the negative charge density on nanochannels and then enhanced the transport of NDS2-. The cascade response of the nanochannels also accord with the properties of IMP (implication) logic gate. In addition, such nanochannels showed good reproducibility and reversibility. Therefore, this cascade response model based on nanochannels has the potential to be used as switches in area of actuators and biosensors, and is also expected to be used to understand the interaction of substances in nanoscale and simulate the physiological functions of boron.
2019, 30(7): 1401-1404
doi: 10.1016/j.cclet.2019.02.024
Abstract:
Boron nitride nanotubes (BNNTs) were treated as brittle materials and could be used to enhance the composite mechanical properties. Many approaches were used to verify the theoretical prediction experimentally, but how to in situ real-time characterize nanomechanical properties of BNNTs was still interested to the researchers. An in situ transmission electron microscopy (TEM) equipped with a force transducer holder had been used to study the structure evolution behavior of BNNTs with axial compression. Real-time video and the force transducer had been used synchronously to record the whole force loading process where the mechanical deformation of BNNT began, buckled and ended with fracture. An individual ultrathin BNNT was employed to conduct the loading test. The results showed that the elastic deformation happened on the BNNT. Young's modulus~1.05-1.37 Tpa and elasticity coefficient~198.7-255.9 N/m of BNNT were calculated by Euler formula and Hooker's law, respectively.
Boron nitride nanotubes (BNNTs) were treated as brittle materials and could be used to enhance the composite mechanical properties. Many approaches were used to verify the theoretical prediction experimentally, but how to in situ real-time characterize nanomechanical properties of BNNTs was still interested to the researchers. An in situ transmission electron microscopy (TEM) equipped with a force transducer holder had been used to study the structure evolution behavior of BNNTs with axial compression. Real-time video and the force transducer had been used synchronously to record the whole force loading process where the mechanical deformation of BNNT began, buckled and ended with fracture. An individual ultrathin BNNT was employed to conduct the loading test. The results showed that the elastic deformation happened on the BNNT. Young's modulus~1.05-1.37 Tpa and elasticity coefficient~198.7-255.9 N/m of BNNT were calculated by Euler formula and Hooker's law, respectively.
2019, 30(7): 1405-1409
doi: 10.1016/j.cclet.2019.04.004
Abstract:
The intermixed phase is important in effective charge separation due to the formation of cascaded energy landscape between intermixed phase and pure phases in polymer/fullerene solar cells. However, the quantitative relationship between the charge separation and the content of intermixed phase has not been investigated clearly so far. Here, we proposed to tune the content of the polymer/PC71BM intermixed phase by changing the polymer solution conformation. Poly[2, 5-bis(3-tetradecylthiophen-2-yl)thieno[3, 2-b]thiophene] (PBTTT) and PC71BM was selected as a model system. The organization of the PBTTT in solution promotes the formation of ordered aggregates as aging time increases, the interdigitation of side-chains restricts the intercalation of PC71BM. Therefore, the intermixed phase formed by intercalation PC71BM to PBTTT side chain can be controlled. When the aging time increasing from 0 to 80 min, the extent of intercalation gradually from almost complete intercalated phase to almost non-intercalated. As the content of intercalated phase is about 11%, the charge dissociation is most efficient and short circuit current (Jsc) increased from 1.60 mA/cm2 to 4.94 mA/cm2, leading to optimized device performance.
The intermixed phase is important in effective charge separation due to the formation of cascaded energy landscape between intermixed phase and pure phases in polymer/fullerene solar cells. However, the quantitative relationship between the charge separation and the content of intermixed phase has not been investigated clearly so far. Here, we proposed to tune the content of the polymer/PC71BM intermixed phase by changing the polymer solution conformation. Poly[2, 5-bis(3-tetradecylthiophen-2-yl)thieno[3, 2-b]thiophene] (PBTTT) and PC71BM was selected as a model system. The organization of the PBTTT in solution promotes the formation of ordered aggregates as aging time increases, the interdigitation of side-chains restricts the intercalation of PC71BM. Therefore, the intermixed phase formed by intercalation PC71BM to PBTTT side chain can be controlled. When the aging time increasing from 0 to 80 min, the extent of intercalation gradually from almost complete intercalated phase to almost non-intercalated. As the content of intercalated phase is about 11%, the charge dissociation is most efficient and short circuit current (Jsc) increased from 1.60 mA/cm2 to 4.94 mA/cm2, leading to optimized device performance.
2019, 30(7): 1410-1414
doi: 10.1016/j.cclet.2019.04.011
Abstract:
Carbon dots (CDs) are prepared through a simple one-step hydrothermal treatment of o-phenylendiamine (OPD) and show yellow photoluminescent (PL) emission under the ultraviolet excitation, which can be further enhanced by Cu2+ ions owing to Cu2+ ions induced aggregation of OPD-CDs through the coordination of Cu2+ with amino groups on the surface of OPD-CDs. The aggregation induced emission enhancement (AIEE) property enables it feasible to develop a simple, sensitive and selective method to detect environmental and intracellular copper (Ⅱ) ions. The limit of detection as lowas 0.28 μmol/L (3σ/k) and a dynamic range from 0.5 μmol/L to 40 μmol/L make it veryeasy to detect the copper content inwater samples, such as river closure reservoir. Furthermore, fluorescence imaging of intracellular Cu2+ suggests that the AIEE features of OPD-CDs specific to Cu2+ ions can be also applied in biological systems.
Carbon dots (CDs) are prepared through a simple one-step hydrothermal treatment of o-phenylendiamine (OPD) and show yellow photoluminescent (PL) emission under the ultraviolet excitation, which can be further enhanced by Cu2+ ions owing to Cu2+ ions induced aggregation of OPD-CDs through the coordination of Cu2+ with amino groups on the surface of OPD-CDs. The aggregation induced emission enhancement (AIEE) property enables it feasible to develop a simple, sensitive and selective method to detect environmental and intracellular copper (Ⅱ) ions. The limit of detection as lowas 0.28 μmol/L (3σ/k) and a dynamic range from 0.5 μmol/L to 40 μmol/L make it veryeasy to detect the copper content inwater samples, such as river closure reservoir. Furthermore, fluorescence imaging of intracellular Cu2+ suggests that the AIEE features of OPD-CDs specific to Cu2+ ions can be also applied in biological systems.
2019, 30(7): 1415-1418
doi: 10.1016/j.cclet.2019.03.008
Abstract:
Favorable physicochemical properties and unique molecular recognition capability endow triptycenebased materials with good potential as stationary phases for gas chromatography (GC). This work reports a new type of triptycene-based materials functionalized by three benzimidazolium cations with different peripheral alkyl lengths (denoted as TP-3Bim-5C and TP-3Bim-12C) and their GC separation performance. As a result, they shared high resolving performance for the naphthalene isomers but differed for the benzene derivatives with varying polarity. Moreover, their capillary columns exhibited good repeatability and thermal stability. This work presents a facile strategy for tailoring the selectivity of the TP-based stationary phases and demonstrates their promising future for chromatographic analysis.
Favorable physicochemical properties and unique molecular recognition capability endow triptycenebased materials with good potential as stationary phases for gas chromatography (GC). This work reports a new type of triptycene-based materials functionalized by three benzimidazolium cations with different peripheral alkyl lengths (denoted as TP-3Bim-5C and TP-3Bim-12C) and their GC separation performance. As a result, they shared high resolving performance for the naphthalene isomers but differed for the benzene derivatives with varying polarity. Moreover, their capillary columns exhibited good repeatability and thermal stability. This work presents a facile strategy for tailoring the selectivity of the TP-based stationary phases and demonstrates their promising future for chromatographic analysis.
2019, 30(7): 1419-1422
doi: 10.1016/j.cclet.2019.03.038
Abstract:
A series of novel 1, 3, 5-thiadiazine-2-thione derivatives bearing a hydrazide moiety were designed, synthesized and evaluated for their antifungal activities against Rhizoctonia solani (Rs), Fusarium graminearum (Fg), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc). The in vitro antifungal bioassays indicated that most of title compounds displayed good selectivity and specificity aganist Rs relative to Fg, Bc and Cc. Strikingly, the title compound N'-(4-chlorophenyl)-2-(5-phenyl-6-thioxo-1, 3, 5-thiadiazinan-3-yl)acethydrazide (5b) obviously inhibited the Rs growth in vitro with the EC50 value of 0.24μg/mL, which is approximately 2-folds more effective than the commercialized fungicide carbendazim (0.55 μg/mL). The in vivo anti-Rs effects of title compound 5b were further evaluated on rice leaves with control efficacies of 98.58% at 200 μg/mL and 61.27% at 100 μg/mL. The above researches provide a significant reference for the further structural optimization of 1, 3, 5-thiadiazine-2-thione derivatives bearing a hydrazide moiety as potential fungicides.
A series of novel 1, 3, 5-thiadiazine-2-thione derivatives bearing a hydrazide moiety were designed, synthesized and evaluated for their antifungal activities against Rhizoctonia solani (Rs), Fusarium graminearum (Fg), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc). The in vitro antifungal bioassays indicated that most of title compounds displayed good selectivity and specificity aganist Rs relative to Fg, Bc and Cc. Strikingly, the title compound N'-(4-chlorophenyl)-2-(5-phenyl-6-thioxo-1, 3, 5-thiadiazinan-3-yl)acethydrazide (5b) obviously inhibited the Rs growth in vitro with the EC50 value of 0.24μg/mL, which is approximately 2-folds more effective than the commercialized fungicide carbendazim (0.55 μg/mL). The in vivo anti-Rs effects of title compound 5b were further evaluated on rice leaves with control efficacies of 98.58% at 200 μg/mL and 61.27% at 100 μg/mL. The above researches provide a significant reference for the further structural optimization of 1, 3, 5-thiadiazine-2-thione derivatives bearing a hydrazide moiety as potential fungicides.
2019, 30(7): 1423-1427
doi: 10.1016/j.cclet.2019.03.004
Abstract:
Herein, we report a "dissolution-reassembly" approach for preparation of N-doped hollow carbon spheres with mesoporous/microporous composite structure (H(Micro/Meso)CS). Basing on the compositional inhomogeneity inside the nanospheres of 3-aminophenol/formaldehyde (3-AF) polymerization, the internal 3-AF oligomer with low-molecular-weight is dissolved by acetone to form cavity. Then the dispersive 3-AF oligomer reassemble with silica oligomer as pore-forming agent and cetyltrimethyl-ammonium bromide as surfactant to form a mesoporous outer shell. In addition, the amount of acetone has a great influence on the morphology and structure of H(Micro/Meso)CS. The obtained H(Micro/Meso)CS shows uniform spherical and microporous/mesoporous shell structure and has a high specific capacity and excellent high rate capability.
Herein, we report a "dissolution-reassembly" approach for preparation of N-doped hollow carbon spheres with mesoporous/microporous composite structure (H(Micro/Meso)CS). Basing on the compositional inhomogeneity inside the nanospheres of 3-aminophenol/formaldehyde (3-AF) polymerization, the internal 3-AF oligomer with low-molecular-weight is dissolved by acetone to form cavity. Then the dispersive 3-AF oligomer reassemble with silica oligomer as pore-forming agent and cetyltrimethyl-ammonium bromide as surfactant to form a mesoporous outer shell. In addition, the amount of acetone has a great influence on the morphology and structure of H(Micro/Meso)CS. The obtained H(Micro/Meso)CS shows uniform spherical and microporous/mesoporous shell structure and has a high specific capacity and excellent high rate capability.
2019, 30(7): 1428-1431
doi: 10.1016/j.cclet.2019.03.009
Abstract:
The ring-opening polymerization (ROP) of N-(tetrafluoroboran ammonium)-L-lysine-N-carboxyanhydride (NH3BF4-Lys NCA) was initiated by triethylamine to prepare hyperbranched polylysine (HPlys) fluoroborate with narrow polydispersity at a low temperature. Both mass spectroscopy analysis and DFT computation evidenced that the resultant cyclic dimer mainly initiated ROP as a secondary species according to normal amine mechanism. The hyperbranched polylysine in aqueous solution existed in a unimolecular state at low concentrations, but transformed into spherical micellar aggregates at a high concentration of 5 mg/mL, as characterized by dynamic laser scattering and transmission electron microscopy. By utilizing multivalent coordination interactions between hyperbranched polylysine and gold, the plasmonic gold nanoparticles (HPlys@Au NPs) were successfully prepared in aqueous solution, which elevated the solution by 23.1 ℃ upon 5 min of NIR laser irradiation (808 nm, 2 W/cm2).
The ring-opening polymerization (ROP) of N-(tetrafluoroboran ammonium)-L-lysine-N-carboxyanhydride (NH3BF4-Lys NCA) was initiated by triethylamine to prepare hyperbranched polylysine (HPlys) fluoroborate with narrow polydispersity at a low temperature. Both mass spectroscopy analysis and DFT computation evidenced that the resultant cyclic dimer mainly initiated ROP as a secondary species according to normal amine mechanism. The hyperbranched polylysine in aqueous solution existed in a unimolecular state at low concentrations, but transformed into spherical micellar aggregates at a high concentration of 5 mg/mL, as characterized by dynamic laser scattering and transmission electron microscopy. By utilizing multivalent coordination interactions between hyperbranched polylysine and gold, the plasmonic gold nanoparticles (HPlys@Au NPs) were successfully prepared in aqueous solution, which elevated the solution by 23.1 ℃ upon 5 min of NIR laser irradiation (808 nm, 2 W/cm2).
2019, 30(7): 1432-1434
doi: 10.1016/j.cclet.2019.03.027
Abstract:
Current synthesis of α-substituted 3, 6-dihydro-2H-pyrans dominantly relies on functional group transformation. Herein, a direct and practical oxidative C-H alkynylation and alkenylation of 3, 6-dihydro-2H-pyran skeletons with a range of potassium trifluoroborates is developed. The metal-free process is well tolerated with a wide variety of 3, 6-dihydro-2H-pyrans, rapidly providing a library of 2, 4-disubstituted 3, 6-dihydro-2H-pyrans with diverse patterns of α-functionalities for further diversification and bioactive small molecule identification.
Current synthesis of α-substituted 3, 6-dihydro-2H-pyrans dominantly relies on functional group transformation. Herein, a direct and practical oxidative C-H alkynylation and alkenylation of 3, 6-dihydro-2H-pyran skeletons with a range of potassium trifluoroborates is developed. The metal-free process is well tolerated with a wide variety of 3, 6-dihydro-2H-pyrans, rapidly providing a library of 2, 4-disubstituted 3, 6-dihydro-2H-pyrans with diverse patterns of α-functionalities for further diversification and bioactive small molecule identification.
2019, 30(7): 1435-1439
doi: 10.1016/j.cclet.2019.05.001
Abstract:
Mitochondrial dysfunction is associated with the emergence of several neurological and cardiovascular diseases. Hence, mitochondria-targeting delivery strategies are highly significant and critically needed. In this study, we developed a small library of peptides simulating the mitochondria-targeting peptide SS-31, a promising tetra-peptide with antioxidant character, and subsequently evaluated the toxicity, antioxidant ability and mitochondrial delivery of nanoparticles. Among the designed peptides, RF-2 (DArg-Dmt-Arg-Phe-NH2) showed controlled toxicity and excellent protection against gentamicin-induced hair cell damage, as compared with SS-31. More importantly, RF-2-modified PLGA nanoparticles demonstrated high colocalization with mitochondria and comparable specific subcellular accumulation, when compared with SS-31. Taken together, the obtained results supported RF-2 as a mitochondriatargeting peptide with high potential as a targeted carrier.
Mitochondrial dysfunction is associated with the emergence of several neurological and cardiovascular diseases. Hence, mitochondria-targeting delivery strategies are highly significant and critically needed. In this study, we developed a small library of peptides simulating the mitochondria-targeting peptide SS-31, a promising tetra-peptide with antioxidant character, and subsequently evaluated the toxicity, antioxidant ability and mitochondrial delivery of nanoparticles. Among the designed peptides, RF-2 (DArg-Dmt-Arg-Phe-NH2) showed controlled toxicity and excellent protection against gentamicin-induced hair cell damage, as compared with SS-31. More importantly, RF-2-modified PLGA nanoparticles demonstrated high colocalization with mitochondria and comparable specific subcellular accumulation, when compared with SS-31. Taken together, the obtained results supported RF-2 as a mitochondriatargeting peptide with high potential as a targeted carrier.
2019, 30(7): 1440-1444
doi: 10.1016/j.cclet.2019.03.014
Abstract:
Two Co(Ⅱ)-MOFs with different structures were successfully synthesized under the premise of designing two ligands containing alkynyl functional groups. Complexes 1 ([Co(TEPA)(TPT)2/3]·2DMF·H2O) and 2 ([Co(EPA)(TPT)]·1.5DMF·1.5H2O) show excellent luminescence properties. Meanwhile, as fluorescent sensors, complexes 1 and 2 exhibit selectivity and sensitivity for Fe3+ with the Ksv of 1.520 ×104 L/mol and 3.543×104 L/mol, which can rapidly detect nitroaromatic compounds in methanol and ethanol, especially for 2, 4-NPH through fluorescence quenching with high quenching efficiency. In particular, the Ksv value of complexes 1 and 2 towards 2, 4-NPH can reach up to 1.627×105 L/mol and 9.600×104 L/mol, demonstrating that complexes 1 and 2 are good candidates for the identification and detection of Fe3+ and nitroaromatic compounds.
Two Co(Ⅱ)-MOFs with different structures were successfully synthesized under the premise of designing two ligands containing alkynyl functional groups. Complexes 1 ([Co(TEPA)(TPT)2/3]·2DMF·H2O) and 2 ([Co(EPA)(TPT)]·1.5DMF·1.5H2O) show excellent luminescence properties. Meanwhile, as fluorescent sensors, complexes 1 and 2 exhibit selectivity and sensitivity for Fe3+ with the Ksv of 1.520 ×104 L/mol and 3.543×104 L/mol, which can rapidly detect nitroaromatic compounds in methanol and ethanol, especially for 2, 4-NPH through fluorescence quenching with high quenching efficiency. In particular, the Ksv value of complexes 1 and 2 towards 2, 4-NPH can reach up to 1.627×105 L/mol and 9.600×104 L/mol, demonstrating that complexes 1 and 2 are good candidates for the identification and detection of Fe3+ and nitroaromatic compounds.
2019, 30(7): 1445-1449
doi: 10.1016/j.cclet.2019.03.010
Abstract:
Hierarchical porous carbons (HPCs) are obtained via in-situ activation of interpenetrating polymer networks (IPNs) obtained from simultaneous polymerization of resorcinol/formaldehyde (R/F) and polyacrylamide (PAM). The hierarchically micro-, meso-and macroporous structure of as-prepared HPCs is attributed to the synergistic pore-forming effect of PAM and KOH, including PAM decomposition, KOH chemical activation, and a foaming process of potassium polyacrylate formed by partial hydrolysis of PAM in KOH aqueous solution. The typical HPC electrode with the highest surface area (2544 m2/g) shows a high specific capacitance of 261 F/g at 1.0 A/g and a superior rate capability of 216 F/g at 20 A/g in alkaline electrolyte. Moreover, the electrode maintains the capacitance retention of 90.8% after 10000 chargingdischarging cycles at 1.0 A/g, exhibiting long cycling life. This study highlights a new avenue towards IPNs-derived carbons with unique pore structure for promising electrochemical applications.
Hierarchical porous carbons (HPCs) are obtained via in-situ activation of interpenetrating polymer networks (IPNs) obtained from simultaneous polymerization of resorcinol/formaldehyde (R/F) and polyacrylamide (PAM). The hierarchically micro-, meso-and macroporous structure of as-prepared HPCs is attributed to the synergistic pore-forming effect of PAM and KOH, including PAM decomposition, KOH chemical activation, and a foaming process of potassium polyacrylate formed by partial hydrolysis of PAM in KOH aqueous solution. The typical HPC electrode with the highest surface area (2544 m2/g) shows a high specific capacitance of 261 F/g at 1.0 A/g and a superior rate capability of 216 F/g at 20 A/g in alkaline electrolyte. Moreover, the electrode maintains the capacitance retention of 90.8% after 10000 chargingdischarging cycles at 1.0 A/g, exhibiting long cycling life. This study highlights a new avenue towards IPNs-derived carbons with unique pore structure for promising electrochemical applications.
2019, 30(7): 1450-1454
doi: 10.1016/j.cclet.2019.03.023
Abstract:
A series of Na-doped 1 wt% Pd/Al2O3 catalysts with different Na loadings were prepared by wet impregnation and tested for the catalytic oxidation of benzene. Suitable addition of Na had a remarkable promotion effect on water resistance and enhancement of low temperature activity of Pd/Al2O3 catalysts. The optimal mole ratio between Na and Pd was 1:1. The properties of the prepared catalysts were characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), O2-temperature-programmed desorption (O2-TPD), and in situ DRIFTS. Results indicated that the addition of Na not only decreased the content of adsorbed water species but also increased the amount of liable surface oxygen species, which are likely the key factors for the excellent water resistance of the catalyst. Na addition also improved the mobility of the lattice oxygen species, which was favorable for catalytic activity. Moreover, the well-dispersed negatively charged Pd particles and suitable redox properties derived from Na addition also contributed to the improved performance and water resistance of the Na1Pd1/Al2O3 catalyst. In situ DRIFTS results revealed that benzene was oxidized to maleate and acetate species via intermediate o-benzoquinone species, which finally turned into harmless CO2 and H2O.
A series of Na-doped 1 wt% Pd/Al2O3 catalysts with different Na loadings were prepared by wet impregnation and tested for the catalytic oxidation of benzene. Suitable addition of Na had a remarkable promotion effect on water resistance and enhancement of low temperature activity of Pd/Al2O3 catalysts. The optimal mole ratio between Na and Pd was 1:1. The properties of the prepared catalysts were characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), O2-temperature-programmed desorption (O2-TPD), and in situ DRIFTS. Results indicated that the addition of Na not only decreased the content of adsorbed water species but also increased the amount of liable surface oxygen species, which are likely the key factors for the excellent water resistance of the catalyst. Na addition also improved the mobility of the lattice oxygen species, which was favorable for catalytic activity. Moreover, the well-dispersed negatively charged Pd particles and suitable redox properties derived from Na addition also contributed to the improved performance and water resistance of the Na1Pd1/Al2O3 catalyst. In situ DRIFTS results revealed that benzene was oxidized to maleate and acetate species via intermediate o-benzoquinone species, which finally turned into harmless CO2 and H2O.
2019, 30(7): 1455-1459
doi: 10.1016/j.cclet.2019.04.050
Abstract:
Silver nanoparticles (AgNPs) are directly grown on surface of ~25 μm copper wire by ultrasound-assisted chemical reduction. Silver nitrate is used as precursors, when polyvinylpyrrolidone (PVP) is added as a controller of the dimension of AgNPs. Influence of growth parameters such as precursor's concentration, ratio proportion of PVP and ultra-sonication on the growth of AgNPs coating are determined. The best morphology, size of the AgNPs are observed on copper wire. The results show that the copper wire coated with AgNPs of ~100 nm diameter exhibits good antioxidation and ohmic contact after sinter on Si substrate at a temperature as low as 320 ℃, is especially suitable as a substitute for silver paste electrode used in silicon solar cells.
Silver nanoparticles (AgNPs) are directly grown on surface of ~25 μm copper wire by ultrasound-assisted chemical reduction. Silver nitrate is used as precursors, when polyvinylpyrrolidone (PVP) is added as a controller of the dimension of AgNPs. Influence of growth parameters such as precursor's concentration, ratio proportion of PVP and ultra-sonication on the growth of AgNPs coating are determined. The best morphology, size of the AgNPs are observed on copper wire. The results show that the copper wire coated with AgNPs of ~100 nm diameter exhibits good antioxidation and ohmic contact after sinter on Si substrate at a temperature as low as 320 ℃, is especially suitable as a substitute for silver paste electrode used in silicon solar cells.
