A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling re...A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling reaction, and reduction reaction).Four kinds of high performance functional polyimides(WuFPI-6 F, WuFPI-BP, WuFPI-BT, and WuFPI-PM) were thus prepared by the condensation polymerization of WuFDA with four commercial dianhydride 6 FDA, BPDA, BTDA, and PMDA, respectively. The polyimides exhibited low dielectric constant, excellent thermal stability, outstanding solubility, good film-forming property, and mechanical properties. The dielectric constants of the polyimides were in the range of 2.28-2.88(f = 10~4 Hz). The 5% weight-loss temperatures(Td 5%)in nitrogen were in the range of 555-584 °C, and the glass transition temperatures(T_g) were in the range of 408-448 °C. The weight loss of WuFPI-BP maintaining at 450 and 500 °C for half an hour was only 0.33% and 1.26%, respectively. All the WuFPIs could be dissolved in almost all organic solvents, even chloroform. The tensile strength and tensile modulus of these films were in the ranges of 78.6-85.7 MPa and 3.1-3.2 GPa, respectively. In addition, the polyimides displayed light color with special fluorescent and resistive switching(ON-OFF) characteristics; the maximum fluorescence emission was observed at 422-424 nm in NMP solution and at 470-548 nm in film state. The memory devices with the configuration of indium tin oxide/WuFPIs/aluminum(ITO/WuFPIs/Al) exhibited distinct volatile memory characteristics of static random access memory(SRAM), with an ON/OFF current ratio of 10~5-10~6. These functional polyimides showed attractive potential applications in the field of high performance flexible polymer photoelectronic devices or polymer memory devices.展开更多
Four new ent-kaurane diterpenes with chiral epoxyangelate moieties, (2′R,3′R)-3 a- (2′,3′-epoxyangeloyloxy)-kaur-16-en-19-oic acid (1), (2′S,3′S)-3 a- (2′,3′-epoxyangeloyloxy)-kaur-16-en-19-oic acid (2), (2′...Four new ent-kaurane diterpenes with chiral epoxyangelate moieties, (2′R,3′R)-3 a- (2′,3′-epoxyangeloyloxy)-kaur-16-en-19-oic acid (1), (2′S,3′S)-3 a- (2′,3′-epoxyangeloyloxy)-kaur-16-en-19-oic acid (2), (2′S,3′R)-3 a- (2',3'-epoxyangeloyloxy)-kaur-16-en-19-oic acid (3) and (2′R,3′S)-3α- (2′,3'-epoxyangeloyloxy)-kaur-16-en-19-oic acid (4), along with eight known diterpenes (5-12), were isolated from Wedelia prostrata. The absolute configurations of the new structures were determined by X-ray crystallography,ECD calculations and chemical methods. All compounds were evaluated for their cytotoxicity activities on human HepG-2 cells,with IC_(50) values of 11.72 ±0.22 μmol/L to 54.75±1.12 μmol/L.展开更多
In this work, the membrane surface of poly（acrylonitrile-co-2-hydroxyethyl methacrylate） （PANCHEMA） was chemically modified by anchoring of phospholipid moieties. The process involved the reaction of hydroxyl grou...In this work, the membrane surface of poly（acrylonitrile-co-2-hydroxyethyl methacrylate） （PANCHEMA） was chemically modified by anchoring of phospholipid moieties. The process involved the reaction of hydroxyl groups on the membrane surface with 2-chloro-2-oxo-1,3,2-dioxaphospholane （COP） followed by the ring-opening reaction of COP with trimethylamine. Chemical differences between the original and the modified membranes were characterized by FT-IR and XPS, It was found that the amount of macrophage adhered on the modified membrane surface is substantially lower than that on polyacrylonitrile （PAN） and PANCHEMA membranes under the same condition, The morphological change of the adherent cell is also suppressed by the generation ofphospholipid moieties on the membrane surface.展开更多
Two poly（aryl ether）s containing naphthyl moieties were prepared from bis（3,5-dimethyl-4-hydroxyphenyl）naphthyl methane （monomer 1） via nucleophilic aromatic substitution polycondensation with bis（4-fluoropheny...Two poly（aryl ether）s containing naphthyl moieties were prepared from bis（3,5-dimethyl-4-hydroxyphenyl）naphthyl methane （monomer 1） via nucleophilic aromatic substitution polycondensation with bis（4-fluorophenyl） ketone and bis（4-fluorophenyl） sulfone. The structures of these polymers were confirmed by 1H NMR. The Mn values of the two polymers were 96,200 and 88,600, respectively. The polymers exhibited good thermal stabilities with 5% mass loss at T 〉 400 and high glass-transition temperature （Ts） of T 〉 250 ℃. Moreover, the resultant polymers were amorphous determined by wide angle X-ray diffraction （WAXD）. ？2009 Lei Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.展开更多
A new reactive graft copolymer, poly(tetramethylene glycol)-graft-omega-propyl sodium sulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH2CH2CH2SO3-Na+), was synthesized by the cationic polymerization of alpha-omega-bifunc...A new reactive graft copolymer, poly(tetramethylene glycol)-graft-omega-propyl sodium sulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH2CH2CH2SO3-Na+), was synthesized by the cationic polymerization of alpha-omega-bifunctional PEG macromonomer ((sic)CH2-PEG-CH2CH2CH2SO3Na) and THF. The obtained copolymer exhibits the expected structure as indicated by the result of characterization. Two amino acids (L-arginine, L-tyrosine) were covalently attached to the copolymer after converting the sulfonate group, to sulfonyl chloride. So the new reactive graft copolymer (PTMG-g-PEG-CH2CH2CH2SO3-Na+) is expected to be very useful in attachment of potentially bioactive moieties to polymer via a hydrophilic PEG spacer.展开更多
New flame-retardant polyimide-silver nanocomposite containing phosphine oxide moiety in the main chain was synthesized by a convenient ultraviolet irradiation technique.A precursor such as AgNO_3 was used as the sourc...New flame-retardant polyimide-silver nanocomposite containing phosphine oxide moiety in the main chain was synthesized by a convenient ultraviolet irradiation technique.A precursor such as AgNO_3 was used as the source of the silver particles.Polyimide 6 as a source of polymer was synthesized by polycondensation reaction of bis（3-aminophenyl） phenyl phosphine oxide 4 with pyromellitic anhydride 5 in the presence of iso-quinoline as base and in m-cresol solution.The resulting composite film was characterized by FTIR spectroscopy,X-ray diffraction（XRD）,transmission electron microscopy（TEM）,thermogravimetry（TGA） and differential scanning calorimetry（DSC）.The average size of the nanometer Ag particles is about 10 nm.The temperature of 5 and 10%weight loss and also the char yield at 600℃of polyimide-silver nanocomposite 6a were higher than the pure PI 6.展开更多
The progress on the molecular design, synthesis and characterizations of some kinds of pyridine-containing heteroaromatic polymers in main chain were reviewed in this paper, they would include polyimides （Pls）, poly...The progress on the molecular design, synthesis and characterizations of some kinds of pyridine-containing heteroaromatic polymers in main chain were reviewed in this paper, they would include polyimides （Pls）, polypyrrolones （PPYs）, poly（pyrrolane-imide）s （PPIs）, and poly（pyrrolane-benzimidazone）s （PPBs） containing pyridine moieties. The pyridine-cantaining polymers reported all exhibit good processability, excellent thermal properties and mechanical properties. However, the contribution of pyridine ring to polymers properties is still need to research further, the heteroaromatic polymers containing pyridine moieties have focused by more and more researchers.展开更多
Hydrogen,as a clean energy carrier,holds significant promise for a wide range of applications[1].Water electrolysis for hydrogen production is regarded as a core technology for environmentally sustainable and pollutio...Hydrogen,as a clean energy carrier,holds significant promise for a wide range of applications[1].Water electrolysis for hydrogen production is regarded as a core technology for environmentally sustainable and pollution-free hydrogen generation.Among various electrolysis technologies,anion exchange membrane water electrolysis(AEMWE)has garnered substantial attention due to its low operational cost and high dynamic response[2].展开更多
Replacing Pt-based electrocatalysts for the oxygen reduction reaction (ORR) with high performance and low-cost non-precious metal catalysts is crucial for the commercialization of fuel cells.Herein,we present a highly...Replacing Pt-based electrocatalysts for the oxygen reduction reaction (ORR) with high performance and low-cost non-precious metal catalysts is crucial for the commercialization of fuel cells.Herein,we present a highly efficient Fe-N-C porous ORR electrocatalyst with FeNx moieties promoted by Fe2N nanoparticles derived from Fe-doped zeolitic imidazolate framework.The best-performing Fe-N-C/HPC-NH3 catalyst exhibits a superior ORR activity with an onset (E0) and half-wave (E1/2) potential of 0.945 and 0.803 V (RHE),respectively,which is comparable to those of the commercial Pt/C in acidic media.Probing and acid-leaching experiments prove that FeNx moieties play an important role in the ORR and the Fe2N can further improve the ORR activity.Density functional theory calculation reveals a synergistic effect that the existence of Fe2N weakens the adsorption of ORR intermediates on active sites and lowers the reaction free energy of the potential limiting step,thus facilitating the ORR.Both experimental evidence and theoretical analysis for the enhancement of ORR activity by Fe2N decoration in Fe-N-C catalyst might inspire a new strategy for rational design of high performance non-precious metal catalysts.展开更多
In this article, we reported the synthesis and characterization of a novel silafluorene-based host material, 1,3-bis（5-methyl-5H- dibenzo[b,d]silol-5-yl）benzene （Me-DBSiB）, for blue phosphorescent organic light-em...In this article, we reported the synthesis and characterization of a novel silafluorene-based host material, 1,3-bis（5-methyl-5H- dibenzo[b,d]silol-5-yl）benzene （Me-DBSiB）, for blue phosphorescent organic light-emitting devices （PHOLEDs）. The Me- DBSiB was constructed by linking 9-methyl-9-silafluorene units to the phenyl framework through the sp3-hybridized silica atom to maintain high singlet and triplet energy, as well as to enhance thermal and photo-stability. The calculated result shows that the phenyl core does not contribute to both the highest occupied molecular orbital and lowest unoccupied molecular orbital. Wide optical energy gap of 4.1 eV was achieved. When the Me-DBSiB was used as the host and iridium （Ⅲ） bis[（4,6-difluorophenyl）pyridinato-N,C2＇]picolate （Firpic） as the vip, a maximum current efficiency was 14.8 cd/A, lower than the counterpart of 1,3-bis（9-carbazolyl）benzene （28 cd/A）. The unbalanced barrier for electron and hole injection to host layer may be responsible for low efficiency. Even so, our results show that silafluorene moieties are promising building blocks for constructing wide-energy-gap host materials.展开更多
The Fe-N-C material represents an attractive oxygen reduction reaction electrocatalyst,and the FeN_(4)moiety has been identified as a very competitive catalytic active site.Fine tuning of the coordination structure of...The Fe-N-C material represents an attractive oxygen reduction reaction electrocatalyst,and the FeN_(4)moiety has been identified as a very competitive catalytic active site.Fine tuning of the coordination structure of FeN_(4)has an essential impact on the catalytic performance.Herein,we construct a sulfur-modified Fe-N-C catalyst with controllable local coordination environment,where the Fe is coordinated with four in-plane N and an axial external S.The external S atom affects not only the electron distribution but also the spin state of Fe in the FeN_(4)active site.The appearance of higher valence states and spin states for Fe demonstrates the increase in unpaired electrons.With the above characteristics,the adsorption and desorption of the reactants at FeN_(4)active sites are optimized,thus promoting the oxygen reduction reaction activity.This work explores the key point in electronic configuration and coordination environment tuning of FeN_(4)through S doping and provides new insight into the construction of M-N-C-based oxygen reduction reaction catalysts.展开更多
Three new ent-kaurane diterpenoids,silvaticusins A-C(1-3),along with a new ent-kaurane dimer silvaticusin D(4)were isolated from the aerial parts of Isodon silvaticus.The structures of these new compounds were establi...Three new ent-kaurane diterpenoids,silvaticusins A-C(1-3),along with a new ent-kaurane dimer silvaticusin D(4)were isolated from the aerial parts of Isodon silvaticus.The structures of these new compounds were established mainly by comprehensive analysis of their NMR and MS data.The absolute configuration of compounds 1 and 4 were determined using a single-crystal X-ray diffraction and computational methods,respectively.Compounds 2 and 3 were found to exhibit remarkable cytotoxic effects against five human tumor cell lines(HL-60,A-549,SMMC-7721,MDA-MB-231,and SW-480),with IC_(50) values spanning from 1.27±0.08 to 7.52±0.33μM.展开更多
The extraction residue from Shengli lignite was sequentially dissolved in cyclohexane, benzene, methanol, ethanol, and isopropanol in an autoclave at 320℃ to afford soluble portions(SPs) 1–5(SP_1-SP_5) and the final...The extraction residue from Shengli lignite was sequentially dissolved in cyclohexane, benzene, methanol, ethanol, and isopropanol in an autoclave at 320℃ to afford soluble portions(SPs) 1–5(SP_1-SP_5) and the final residue(FR). The total yield of SP_1-SP_5 is ca. 55.1%. The FR was subjected to ruthenium ioncatalyzed oxidation and the resulting products were isolated from the reaction mixture and esterified.Both the esterified products and SP_1-SP_5 were analyzed with a gas chromatograph/mass spectrometer.In total, 342 compounds were identified in SP_1-SP_5. They can be classified into normal alkanes, branched alkanes, alkenes, alkanedienes, arenes, alkanols, methylcycloalkanes, alkenols, alkylbenzenemethanols,arenols, anisol and substituted anisols, polymethyldihydrobenzofurans, arenofurans, dibenzofurans,ethoxymethylbenzenes, aldehydes, ketones, esters, nitrogen-containing organic compounds, sulfurcontaining organic compounds, and other compounds. Among the compounds, arenols are predominant in SP_1 and SP_2 and the main compounds in SP_3, while the main compounds in SP_4 and SP_5 are esters and arenes, respectively. According to the esterified products identified, the products from the FR oxidation can be grouped into non-benzene ring carboxylic acids(NBCAs) and benzenepolycarboxylic acids(BPCAs). The total yield of BPCAs is much higher than that of NBCAs, suggesting that the FR is rich in condensed aromatic moieties.展开更多
Variations in the abundance of soil organic matter(SOM) constituents with different stability have a major impact on important environmental processes, e.g., carbon dioxide(CO2) fluxes between the soil and the atmosph...Variations in the abundance of soil organic matter(SOM) constituents with different stability have a major impact on important environmental processes, e.g., carbon dioxide(CO2) fluxes between the soil and the atmosphere. Recently, besides the bulk Rock-Eval(RE) data, the mathematical deconvolution of the signals derived from hydrocarbon-like compounds released by thermal cracking of SOM during RE pyrolysis has been increasingly used to estimate the relative contribution of the major SOM classes differing in origin and preservation. This study applied the mathematical deconvolution of the S3 and S4 signals of carbon monoxide(CO) and CO2, produced both by the pyrolysis of the oxygen-containing moieties and by the oxidation of the residual highly resistant organic matter, to characterize the stability of these components. Our results suggested that the stability of the oxygen-containing moieties was controlled by the precursor material and was strongly affected by the land use and the presence of humic substances in the surface horizon of some main soil types in Hungary. In consistence with the bulk RE data, results of the mathematical deconvolution also proved to be diagnostic markers for discriminating the aquatic or terrigenous plants as the main sources of SOM. The mathematical deconvolution of S4 signals derived from the highly resistant SOM fraction allowed us to quantify the contribution of constituents with different stability. Furthermore, the results of this study displayed that the stability of this highly abundant SOM fraction in the surface soil samples depended on source biomass and intensity of leaching.展开更多
In order to search for novel potent and environmentally benign insecticides,a series of anthranilic diamides containing various fluorinated groups were designed and synthesized.Their structures were confirmed by -1H N...In order to search for novel potent and environmentally benign insecticides,a series of anthranilic diamides containing various fluorinated groups were designed and synthesized.Their structures were confirmed by -1H NMR,-（13）C NMR,-（19）F NMR,elemental analysis,HRMS or mass spectra.Their insecticidal activities against oriental armyworm（Mythimna separata） and diamondback moth（Plutella xyiostella）were evaluated.The preliminary structure-activity relationship（SAR） was discussed in detail.The biological assay indicated that most of the compounds exhibited moderate to excellent insecticidal activities.Especially,Ia showed high larvicidal activity against oriental armyworm.Meanwhile,Iu had better larvicidal effects against diamondback moth than commercial chlorantraniliprole.展开更多
Seven new Schiff bases, which are 4,4,4-trifluo-ro-1-(2-thienyl)-1-butanone-3-Z, Z =-thioseraicarbazone (a); -thiocarbohydrazone (b),-benzoic hydrazone (c), -( o-hydroxyphenyl) imine (d) ,-nicotinic hydrazone (e),-sal...Seven new Schiff bases, which are 4,4,4-trifluo-ro-1-(2-thienyl)-1-butanone-3-Z, Z =-thioseraicarbazone (a); -thiocarbohydrazone (b),-benzoic hydrazone (c), -( o-hydroxyphenyl) imine (d) ,-nicotinic hydrazone (e),-salicylic hydrazone (f), and -(p-fluoro-m-chlorophenyl) imine (g), have been synthesized by reaction of 4, 4, 4-trifluoro-1-(2-thienyl)-1,3-butanedione (TFTBD) with corresponding hy-drazides or anilines, acetic acid or p-toluence sulfonic acid as catalyst, and characterized by Elemental analysis, IR, UV-Vis,1H NMR and MS. The MS spectra confirmed that the -C3=O condensed with primary amino group. Tauto-merism of the compounds is discussed.展开更多
BACKGROUND Thiopurine-induced leukopenia(TIL)is a life-threatening toxicity and occurs with a high frequency in the Asian population.Although nucleoside diphosphate-linked moiety X-type motif 15(NUDT15)variants signif...BACKGROUND Thiopurine-induced leukopenia(TIL)is a life-threatening toxicity and occurs with a high frequency in the Asian population.Although nucleoside diphosphate-linked moiety X-type motif 15(NUDT15)variants significantly improve the predictive sensitivity of TIL,more than 50%of cases of this toxicity cannot be predicted by this mutation.The potential use of the 6-thioguanine nucleotide(6TGN)level to predict TIL has been explored,but no decisive conclusion has been reached.Can we increase the predictive sensitivity based on 6TGN by subgrouping patients according to their NUDT15 R139C genotypes?AIM To determine the 6TGN cut-off levels after dividing patients into subgroups according to their NUDT15 R139C genotypes.METHODS Patients’clinical and epidemiological characteristics were collected from medical records from July 2014 to February 2017.NUDT15 R139C,thiopurine S methyltransferase,and 6TGN concentrations were measured.RESULTS A total of 411 Crohn’s disease patients were included.TIL was observed in 72 individuals with a median 6TGN level of 323.4 pmol/8×10^8 red blood cells(RBC),which was not different from that of patients without TIL(P=0.071).Then,we compared the 6TGN levels based on NUDT15 R139C.For CC(n=342)and CT(n=65)genotypes,the median 6TGN level in patients with TIL was significantly higher than that in patients without(474.8 vs 306.0 pmol/8×10^8 RBC,P=9.4×10-^5;291.7 vs 217.6 pmol/8×10^8 RBC,P=0.039,respectively).The four TT carriers developed TIL,with a median 6TGN concentration of 135.8 pmol/8×10^8 RBC.The 6TGN cut-off levels were 411.5 and 319.2 pmol/8×108 RBC for the CC and CT groups,respectively.CONCLUSION The predictive sensitivity of TIL based on 6TGN is dramatically increased after subgrouping according to NUDT15 R139C genotypes.Applying 6TGN cut-off levels to adjust thiopurine therapies based on NUDT15 is strongly recommended.展开更多
A novel β-cyclodextrin(β-CD)derivative bearing diethanolamine moiety was synthesized by a convenient method with 63% yield,and the new host compound was characterized by (13)~C-NMR,FT-IR spectra etc,
Lithium–sulfur batteries are one of the attractive next-generation energy storage systems owing to theienvironmental friendliness,low cost,and high specific energy densities.However,the low electrical conductivity of...Lithium–sulfur batteries are one of the attractive next-generation energy storage systems owing to theienvironmental friendliness,low cost,and high specific energy densities.However,the low electrical conductivity of sulfur,shuttling of soluble intermediate polysulfides between electrodes,and low capacitretention have hampered their commercial use.To address these issues,we use a halloysitemodulated(H-M)separator in a lithium–sulfur battery to mitigate the shuttling problem.The H-M separator acts as a mutual Coulombic repulsion in lithium-sulfur batteries,thereby selectively permitting Lions and efficiently suppressing the transfer of undesired lithium polysulfides to the Li anode sideMoreover,the use of halloysite switches the surface of the separator from hydrophobic to hydrophilicconsequently improving the electrolyte wettability and adhesion between the separator and cathodeWhen sulfur-multi-walled carbon nanotube(S-MWCNT)composites are used as cathode active materialsa lithium–sulfur battery with an H-M separator exhibits first discharge and charge capacities of 1587 an1527 m Ah g-1,respectively.Moreover,there is a consistent capacity retention up to 100 cyclesAccordingly,our approach demonstrates an economical and easily accessible strategy for commercialization of lithium–sulfur batteries.展开更多
Permanganate has attracted much attention in wide range of chemistry and particularly in degradation of environmental pollutants.However,few studies have discussed the feature of regioselective reactivity of permangan...Permanganate has attracted much attention in wide range of chemistry and particularly in degradation of environmental pollutants.However,few studies have discussed the feature of regioselective reactivity of permanganate with specific moiety of the target compound.Herein,we studied the reaction between permanganate and tetracycline that is an emerging micropollutant with different species containing several electron-rich groups.The second-order rate constants increased from 6.0 to 9.0 and could be quantitatively modeled by considering the speciation of both reactants,yielding kTC0=11.7(mol/L)^-1 sec^-1,kTC-=35.7(mol/L)^-1 sec^-1,kTC2-=43.1(mol/L)^-1 sec^-1 for individual reaction channels.Degradation products were then identified as the hydroxylated and demethylated compounds.The result suggested a rate-limiting step of simple hydroxylation at the phenolic and/or alkene moieties,while the demethylation should be caused by the unavoidably formed manganese oxide via single electron oxidation.This is supported by the DFT calculation,indicating the primary oxidation of phenolic group of TC0 with activation barrier of 44.5 kcal/mol and of alkene group of TC-and TC2-with activation barriers of 44.0 and 43.4 kcal/mol,respectively.This is in agreement with the experimental results,implying the alternation of regioselectivity associated with the deprotonation process.The result was further supported by performing the Fukui function and electrostatic potential analysis,reflecting the more probable site and better electron donating tendency beneficial to the permanganate oxidation.展开更多
基金financial support by the National 973 Program of China (No. 2014CB643605)the National Natural Science Foundation of China (Nos. 51373204 and 51873239)+3 种基金the Science and Technology Project of Guangdong Province (Nos. 2015B090915003 and 2015B090913003)the China Postdoctoral Science Foundation (No. 2017M612801)the Leading Scientific, Technical and Innovation Talents of Guangdong Special Support Program (No. 2016TX03C295)the Fundamental Research Funds for the Central Universities (No. 161gzd08)
文摘A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling reaction, and reduction reaction).Four kinds of high performance functional polyimides(WuFPI-6 F, WuFPI-BP, WuFPI-BT, and WuFPI-PM) were thus prepared by the condensation polymerization of WuFDA with four commercial dianhydride 6 FDA, BPDA, BTDA, and PMDA, respectively. The polyimides exhibited low dielectric constant, excellent thermal stability, outstanding solubility, good film-forming property, and mechanical properties. The dielectric constants of the polyimides were in the range of 2.28-2.88(f = 10~4 Hz). The 5% weight-loss temperatures(Td 5%)in nitrogen were in the range of 555-584 °C, and the glass transition temperatures(T_g) were in the range of 408-448 °C. The weight loss of WuFPI-BP maintaining at 450 and 500 °C for half an hour was only 0.33% and 1.26%, respectively. All the WuFPIs could be dissolved in almost all organic solvents, even chloroform. The tensile strength and tensile modulus of these films were in the ranges of 78.6-85.7 MPa and 3.1-3.2 GPa, respectively. In addition, the polyimides displayed light color with special fluorescent and resistive switching(ON-OFF) characteristics; the maximum fluorescence emission was observed at 422-424 nm in NMP solution and at 470-548 nm in film state. The memory devices with the configuration of indium tin oxide/WuFPIs/aluminum(ITO/WuFPIs/Al) exhibited distinct volatile memory characteristics of static random access memory(SRAM), with an ON/OFF current ratio of 10~5-10~6. These functional polyimides showed attractive potential applications in the field of high performance flexible polymer photoelectronic devices or polymer memory devices.
基金financially supported by the National Natural Science Foundation of China(Nos.81473116,81673319,81673670)Science and Technology Planning Project of Guangdong Province (Nos. 2016A030303011, 2016B030301004)+2 种基金Natural Science Foundation of Guangdong Province(No. 2017A030313732)China Postdoctoral Science Foundation(No. 55350202)Natural Science Foundation of Chongqing(No. cstc2013jcyjA10065)
文摘Four new ent-kaurane diterpenes with chiral epoxyangelate moieties, (2′R,3′R)-3 a- (2′,3′-epoxyangeloyloxy)-kaur-16-en-19-oic acid (1), (2′S,3′S)-3 a- (2′,3′-epoxyangeloyloxy)-kaur-16-en-19-oic acid (2), (2′S,3′R)-3 a- (2',3'-epoxyangeloyloxy)-kaur-16-en-19-oic acid (3) and (2′R,3′S)-3α- (2′,3'-epoxyangeloyloxy)-kaur-16-en-19-oic acid (4), along with eight known diterpenes (5-12), were isolated from Wedelia prostrata. The absolute configurations of the new structures were determined by X-ray crystallography,ECD calculations and chemical methods. All compounds were evaluated for their cytotoxicity activities on human HepG-2 cells,with IC_(50) values of 11.72 ±0.22 μmol/L to 54.75±1.12 μmol/L.
基金This work was financially supported by the National Natural Science Foundation of China(No.50273032).
文摘In this work, the membrane surface of poly（acrylonitrile-co-2-hydroxyethyl methacrylate） （PANCHEMA） was chemically modified by anchoring of phospholipid moieties. The process involved the reaction of hydroxyl groups on the membrane surface with 2-chloro-2-oxo-1,3,2-dioxaphospholane （COP） followed by the ring-opening reaction of COP with trimethylamine. Chemical differences between the original and the modified membranes were characterized by FT-IR and XPS, It was found that the amount of macrophage adhered on the modified membrane surface is substantially lower than that on polyacrylonitrile （PAN） and PANCHEMA membranes under the same condition, The morphological change of the adherent cell is also suppressed by the generation ofphospholipid moieties on the membrane surface.
基金supported by Natural Science Foundation of Guangdong Province(No.7301357)Science and Technology Projects of Shenzhen City(No.200724).
文摘Two poly（aryl ether）s containing naphthyl moieties were prepared from bis（3,5-dimethyl-4-hydroxyphenyl）naphthyl methane （monomer 1） via nucleophilic aromatic substitution polycondensation with bis（4-fluorophenyl） ketone and bis（4-fluorophenyl） sulfone. The structures of these polymers were confirmed by 1H NMR. The Mn values of the two polymers were 96,200 and 88,600, respectively. The polymers exhibited good thermal stabilities with 5% mass loss at T 〉 400 and high glass-transition temperature （Ts） of T 〉 250 ℃. Moreover, the resultant polymers were amorphous determined by wide angle X-ray diffraction （WAXD）. ？2009 Lei Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.
基金Supported by the National Natural Science Foundation of China and Huoyindong Education Foundation
文摘A new reactive graft copolymer, poly(tetramethylene glycol)-graft-omega-propyl sodium sulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH2CH2CH2SO3-Na+), was synthesized by the cationic polymerization of alpha-omega-bifunctional PEG macromonomer ((sic)CH2-PEG-CH2CH2CH2SO3Na) and THF. The obtained copolymer exhibits the expected structure as indicated by the result of characterization. Two amino acids (L-arginine, L-tyrosine) were covalently attached to the copolymer after converting the sulfonate group, to sulfonyl chloride. So the new reactive graft copolymer (PTMG-g-PEG-CH2CH2CH2SO3-Na+) is expected to be very useful in attachment of potentially bioactive moieties to polymer via a hydrophilic PEG spacer.
文摘New flame-retardant polyimide-silver nanocomposite containing phosphine oxide moiety in the main chain was synthesized by a convenient ultraviolet irradiation technique.A precursor such as AgNO_3 was used as the source of the silver particles.Polyimide 6 as a source of polymer was synthesized by polycondensation reaction of bis（3-aminophenyl） phenyl phosphine oxide 4 with pyromellitic anhydride 5 in the presence of iso-quinoline as base and in m-cresol solution.The resulting composite film was characterized by FTIR spectroscopy,X-ray diffraction（XRD）,transmission electron microscopy（TEM）,thermogravimetry（TGA） and differential scanning calorimetry（DSC）.The average size of the nanometer Ag particles is about 10 nm.The temperature of 5 and 10%weight loss and also the char yield at 600℃of polyimide-silver nanocomposite 6a were higher than the pure PI 6.
文摘The progress on the molecular design, synthesis and characterizations of some kinds of pyridine-containing heteroaromatic polymers in main chain were reviewed in this paper, they would include polyimides （Pls）, polypyrrolones （PPYs）, poly（pyrrolane-imide）s （PPIs）, and poly（pyrrolane-benzimidazone）s （PPBs） containing pyridine moieties. The pyridine-cantaining polymers reported all exhibit good processability, excellent thermal properties and mechanical properties. However, the contribution of pyridine ring to polymers properties is still need to research further, the heteroaromatic polymers containing pyridine moieties have focused by more and more researchers.
文摘Hydrogen,as a clean energy carrier,holds significant promise for a wide range of applications[1].Water electrolysis for hydrogen production is regarded as a core technology for environmentally sustainable and pollution-free hydrogen generation.Among various electrolysis technologies,anion exchange membrane water electrolysis(AEMWE)has garnered substantial attention due to its low operational cost and high dynamic response[2].
基金the National Key Research and Development Program of China (No.2017YFA0206500)the National Natural Science Foundation of China (Nos.21802161,21673275,and 21533005).
文摘Replacing Pt-based electrocatalysts for the oxygen reduction reaction (ORR) with high performance and low-cost non-precious metal catalysts is crucial for the commercialization of fuel cells.Herein,we present a highly efficient Fe-N-C porous ORR electrocatalyst with FeNx moieties promoted by Fe2N nanoparticles derived from Fe-doped zeolitic imidazolate framework.The best-performing Fe-N-C/HPC-NH3 catalyst exhibits a superior ORR activity with an onset (E0) and half-wave (E1/2) potential of 0.945 and 0.803 V (RHE),respectively,which is comparable to those of the commercial Pt/C in acidic media.Probing and acid-leaching experiments prove that FeNx moieties play an important role in the ORR and the Fe2N can further improve the ORR activity.Density functional theory calculation reveals a synergistic effect that the existence of Fe2N weakens the adsorption of ORR intermediates on active sites and lowers the reaction free energy of the potential limiting step,thus facilitating the ORR.Both experimental evidence and theoretical analysis for the enhancement of ORR activity by Fe2N decoration in Fe-N-C catalyst might inspire a new strategy for rational design of high performance non-precious metal catalysts.
基金supported by the Fundamental Research Funds for the Central Universities(08143034)the National Basic Research Program of China(2013CB328705)the National Natural Science Foundation of China(61275034,61106123)
文摘In this article, we reported the synthesis and characterization of a novel silafluorene-based host material, 1,3-bis（5-methyl-5H- dibenzo[b,d]silol-5-yl）benzene （Me-DBSiB）, for blue phosphorescent organic light-emitting devices （PHOLEDs）. The Me- DBSiB was constructed by linking 9-methyl-9-silafluorene units to the phenyl framework through the sp3-hybridized silica atom to maintain high singlet and triplet energy, as well as to enhance thermal and photo-stability. The calculated result shows that the phenyl core does not contribute to both the highest occupied molecular orbital and lowest unoccupied molecular orbital. Wide optical energy gap of 4.1 eV was achieved. When the Me-DBSiB was used as the host and iridium （Ⅲ） bis[（4,6-difluorophenyl）pyridinato-N,C2＇]picolate （Firpic） as the vip, a maximum current efficiency was 14.8 cd/A, lower than the counterpart of 1,3-bis（9-carbazolyl）benzene （28 cd/A）. The unbalanced barrier for electron and hole injection to host layer may be responsible for low efficiency. Even so, our results show that silafluorene moieties are promising building blocks for constructing wide-energy-gap host materials.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFA0715000)the National Natural Science Foundation of China(Grant No.52127816)+2 种基金supported by the U.S.Department of Energy(DOE),Office of Energy Efficiency and Renewable Energy,Vehicle Technologies Officethe DOE Office of Science by UChicago Argonne LLC under contract no.DE-AC02-06CH11357the Advanced Photon Source(APS),a U.S.Department of Energy(DOE)Office of Science User Facility,operated for the DOE Office of Science by Argonne National Laboratory under Contract No.DE-AC02-06CH11357
文摘The Fe-N-C material represents an attractive oxygen reduction reaction electrocatalyst,and the FeN_(4)moiety has been identified as a very competitive catalytic active site.Fine tuning of the coordination structure of FeN_(4)has an essential impact on the catalytic performance.Herein,we construct a sulfur-modified Fe-N-C catalyst with controllable local coordination environment,where the Fe is coordinated with four in-plane N and an axial external S.The external S atom affects not only the electron distribution but also the spin state of Fe in the FeN_(4)active site.The appearance of higher valence states and spin states for Fe demonstrates the increase in unpaired electrons.With the above characteristics,the adsorption and desorption of the reactants at FeN_(4)active sites are optimized,thus promoting the oxygen reduction reaction activity.This work explores the key point in electronic configuration and coordination environment tuning of FeN_(4)through S doping and provides new insight into the construction of M-N-C-based oxygen reduction reaction catalysts.
基金supported by the National Science Fund for Distinguished Young Scholars(82325047)Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0502)+1 种基金NSFC-Joint Foundation of Yunnan Province(U2002221)Youth Innovation Promotion Association CAS(2023409).
文摘Three new ent-kaurane diterpenoids,silvaticusins A-C(1-3),along with a new ent-kaurane dimer silvaticusin D(4)were isolated from the aerial parts of Isodon silvaticus.The structures of these new compounds were established mainly by comprehensive analysis of their NMR and MS data.The absolute configuration of compounds 1 and 4 were determined using a single-crystal X-ray diffraction and computational methods,respectively.Compounds 2 and 3 were found to exhibit remarkable cytotoxic effects against five human tumor cell lines(HL-60,A-549,SMMC-7721,MDA-MB-231,and SW-480),with IC_(50) values spanning from 1.27±0.08 to 7.52±0.33μM.
基金provided by the Key Project of Joint Fund from National Natural Science Foundation of Chinathe Government of Xinjiang Uygur Autonomous Region (Grant U1503293)+1 种基金Natural Scientific Foundation of China (Grant 21576280)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The extraction residue from Shengli lignite was sequentially dissolved in cyclohexane, benzene, methanol, ethanol, and isopropanol in an autoclave at 320℃ to afford soluble portions(SPs) 1–5(SP_1-SP_5) and the final residue(FR). The total yield of SP_1-SP_5 is ca. 55.1%. The FR was subjected to ruthenium ioncatalyzed oxidation and the resulting products were isolated from the reaction mixture and esterified.Both the esterified products and SP_1-SP_5 were analyzed with a gas chromatograph/mass spectrometer.In total, 342 compounds were identified in SP_1-SP_5. They can be classified into normal alkanes, branched alkanes, alkenes, alkanedienes, arenes, alkanols, methylcycloalkanes, alkenols, alkylbenzenemethanols,arenols, anisol and substituted anisols, polymethyldihydrobenzofurans, arenofurans, dibenzofurans,ethoxymethylbenzenes, aldehydes, ketones, esters, nitrogen-containing organic compounds, sulfurcontaining organic compounds, and other compounds. Among the compounds, arenols are predominant in SP_1 and SP_2 and the main compounds in SP_3, while the main compounds in SP_4 and SP_5 are esters and arenes, respectively. According to the esterified products identified, the products from the FR oxidation can be grouped into non-benzene ring carboxylic acids(NBCAs) and benzenepolycarboxylic acids(BPCAs). The total yield of BPCAs is much higher than that of NBCAs, suggesting that the FR is rich in condensed aromatic moieties.
基金Supported by the Hungarian Scientific Research Fund(No.OTKA K-81181)
文摘Variations in the abundance of soil organic matter(SOM) constituents with different stability have a major impact on important environmental processes, e.g., carbon dioxide(CO2) fluxes between the soil and the atmosphere. Recently, besides the bulk Rock-Eval(RE) data, the mathematical deconvolution of the signals derived from hydrocarbon-like compounds released by thermal cracking of SOM during RE pyrolysis has been increasingly used to estimate the relative contribution of the major SOM classes differing in origin and preservation. This study applied the mathematical deconvolution of the S3 and S4 signals of carbon monoxide(CO) and CO2, produced both by the pyrolysis of the oxygen-containing moieties and by the oxidation of the residual highly resistant organic matter, to characterize the stability of these components. Our results suggested that the stability of the oxygen-containing moieties was controlled by the precursor material and was strongly affected by the land use and the presence of humic substances in the surface horizon of some main soil types in Hungary. In consistence with the bulk RE data, results of the mathematical deconvolution also proved to be diagnostic markers for discriminating the aquatic or terrigenous plants as the main sources of SOM. The mathematical deconvolution of S4 signals derived from the highly resistant SOM fraction allowed us to quantify the contribution of constituents with different stability. Furthermore, the results of this study displayed that the stability of this highly abundant SOM fraction in the surface soil samples depended on source biomass and intensity of leaching.
基金financially supported by the National Natural Science Foundation of China(No.21372133)973 Program(No.2010CB126106)"111" Project of Ministry of Education of China(No.B06005)
文摘In order to search for novel potent and environmentally benign insecticides,a series of anthranilic diamides containing various fluorinated groups were designed and synthesized.Their structures were confirmed by -1H NMR,-（13）C NMR,-（19）F NMR,elemental analysis,HRMS or mass spectra.Their insecticidal activities against oriental armyworm（Mythimna separata） and diamondback moth（Plutella xyiostella）were evaluated.The preliminary structure-activity relationship（SAR） was discussed in detail.The biological assay indicated that most of the compounds exhibited moderate to excellent insecticidal activities.Especially,Ia showed high larvicidal activity against oriental armyworm.Meanwhile,Iu had better larvicidal effects against diamondback moth than commercial chlorantraniliprole.
文摘Seven new Schiff bases, which are 4,4,4-trifluo-ro-1-(2-thienyl)-1-butanone-3-Z, Z =-thioseraicarbazone (a); -thiocarbohydrazone (b),-benzoic hydrazone (c), -( o-hydroxyphenyl) imine (d) ,-nicotinic hydrazone (e),-salicylic hydrazone (f), and -(p-fluoro-m-chlorophenyl) imine (g), have been synthesized by reaction of 4, 4, 4-trifluoro-1-(2-thienyl)-1,3-butanedione (TFTBD) with corresponding hy-drazides or anilines, acetic acid or p-toluence sulfonic acid as catalyst, and characterized by Elemental analysis, IR, UV-Vis,1H NMR and MS. The MS spectra confirmed that the -C3=O condensed with primary amino group. Tauto-merism of the compounds is discussed.
基金Supported by the National Natural Science Foundation of China,No.81573507,No.81473283,No.81173131,and No.81320108027Guangdong Provincial Key Laboratory Construction Foundation,No.2017B030314030+1 种基金The National Key Research and Development Program,No.2016YFC0905003the 111 Project,No.B16047
文摘BACKGROUND Thiopurine-induced leukopenia(TIL)is a life-threatening toxicity and occurs with a high frequency in the Asian population.Although nucleoside diphosphate-linked moiety X-type motif 15(NUDT15)variants significantly improve the predictive sensitivity of TIL,more than 50%of cases of this toxicity cannot be predicted by this mutation.The potential use of the 6-thioguanine nucleotide(6TGN)level to predict TIL has been explored,but no decisive conclusion has been reached.Can we increase the predictive sensitivity based on 6TGN by subgrouping patients according to their NUDT15 R139C genotypes?AIM To determine the 6TGN cut-off levels after dividing patients into subgroups according to their NUDT15 R139C genotypes.METHODS Patients’clinical and epidemiological characteristics were collected from medical records from July 2014 to February 2017.NUDT15 R139C,thiopurine S methyltransferase,and 6TGN concentrations were measured.RESULTS A total of 411 Crohn’s disease patients were included.TIL was observed in 72 individuals with a median 6TGN level of 323.4 pmol/8×10^8 red blood cells(RBC),which was not different from that of patients without TIL(P=0.071).Then,we compared the 6TGN levels based on NUDT15 R139C.For CC(n=342)and CT(n=65)genotypes,the median 6TGN level in patients with TIL was significantly higher than that in patients without(474.8 vs 306.0 pmol/8×10^8 RBC,P=9.4×10-^5;291.7 vs 217.6 pmol/8×10^8 RBC,P=0.039,respectively).The four TT carriers developed TIL,with a median 6TGN concentration of 135.8 pmol/8×10^8 RBC.The 6TGN cut-off levels were 411.5 and 319.2 pmol/8×108 RBC for the CC and CT groups,respectively.CONCLUSION The predictive sensitivity of TIL based on 6TGN is dramatically increased after subgrouping according to NUDT15 R139C genotypes.Applying 6TGN cut-off levels to adjust thiopurine therapies based on NUDT15 is strongly recommended.
文摘A novel β-cyclodextrin(β-CD)derivative bearing diethanolamine moiety was synthesized by a convenient method with 63% yield,and the new host compound was characterized by (13)~C-NMR,FT-IR spectra etc,
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIP)(No.2018R1C1B6004689)the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2020R1I1A306182111)the Electronics and Telecommunications Research Institute(ETRI)grant funded by the Korean government(21ZB1200,Development of ICT Materials,Components and Equipment Technologies)。
文摘Lithium–sulfur batteries are one of the attractive next-generation energy storage systems owing to theienvironmental friendliness,low cost,and high specific energy densities.However,the low electrical conductivity of sulfur,shuttling of soluble intermediate polysulfides between electrodes,and low capacitretention have hampered their commercial use.To address these issues,we use a halloysitemodulated(H-M)separator in a lithium–sulfur battery to mitigate the shuttling problem.The H-M separator acts as a mutual Coulombic repulsion in lithium-sulfur batteries,thereby selectively permitting Lions and efficiently suppressing the transfer of undesired lithium polysulfides to the Li anode sideMoreover,the use of halloysite switches the surface of the separator from hydrophobic to hydrophilicconsequently improving the electrolyte wettability and adhesion between the separator and cathodeWhen sulfur-multi-walled carbon nanotube(S-MWCNT)composites are used as cathode active materialsa lithium–sulfur battery with an H-M separator exhibits first discharge and charge capacities of 1587 an1527 m Ah g-1,respectively.Moreover,there is a consistent capacity retention up to 100 cyclesAccordingly,our approach demonstrates an economical and easily accessible strategy for commercialization of lithium–sulfur batteries.
基金supported by the National Key R&D Program of China(No.2018YFC0406304)the Central Public-Interest Scientific Institution Basal Research Fund(No.1610232019005)the Agricultural Science and Technology Innovation Program(No.ASTIPTRIC06)
文摘Permanganate has attracted much attention in wide range of chemistry and particularly in degradation of environmental pollutants.However,few studies have discussed the feature of regioselective reactivity of permanganate with specific moiety of the target compound.Herein,we studied the reaction between permanganate and tetracycline that is an emerging micropollutant with different species containing several electron-rich groups.The second-order rate constants increased from 6.0 to 9.0 and could be quantitatively modeled by considering the speciation of both reactants,yielding kTC0=11.7(mol/L)^-1 sec^-1,kTC-=35.7(mol/L)^-1 sec^-1,kTC2-=43.1(mol/L)^-1 sec^-1 for individual reaction channels.Degradation products were then identified as the hydroxylated and demethylated compounds.The result suggested a rate-limiting step of simple hydroxylation at the phenolic and/or alkene moieties,while the demethylation should be caused by the unavoidably formed manganese oxide via single electron oxidation.This is supported by the DFT calculation,indicating the primary oxidation of phenolic group of TC0 with activation barrier of 44.5 kcal/mol and of alkene group of TC-and TC2-with activation barriers of 44.0 and 43.4 kcal/mol,respectively.This is in agreement with the experimental results,implying the alternation of regioselectivity associated with the deprotonation process.The result was further supported by performing the Fukui function and electrostatic potential analysis,reflecting the more probable site and better electron donating tendency beneficial to the permanganate oxidation.
