探究秦川牛宰后成熟过程中线粒体Tu翻译延长因子(mitochondrial Tu translation elongation factor,TUFM)表达对肉的持水性影响。以秦川牛背最长肌为研究对象,测定4℃不同成熟时间下的pH值、贮藏损失、离心损失、蒸煮损失、水分分布、...探究秦川牛宰后成熟过程中线粒体Tu翻译延长因子(mitochondrial Tu translation elongation factor,TUFM)表达对肉的持水性影响。以秦川牛背最长肌为研究对象,测定4℃不同成熟时间下的pH值、贮藏损失、离心损失、蒸煮损失、水分分布、肌原纤维蛋白等指标变化情况,测定不同成熟时间(0、96、192 h)下TUFM表达量及其含量、Beclin1蛋白表达量。结果显示:在秦川牛宰后成熟期间,肌原纤维蛋白发生降解,TUFM的表达量与Beclin1蛋白表达量和牛肉的持水性存在密切关系,其中蛋白质组学测定的TUFM表达量变化与TUFM含量变化趋势一致,Beclin1蛋白表达量、贮藏损失、离心损失、蒸煮损失整体均呈先上升后下降趋势,pH值呈先下降后上升趋势;Pearson相关性分析表明,牛背最长肌中TUFM表达量与低场核磁共振峰面积比P_(2b)、Beclin1蛋白表达量呈极显著正相关(P<0.01),与贮藏损失、离心损失、蒸煮损失呈显著正相关(P<0.05),与P_(21)呈极显著负相关(P<0.01),与P_(22)呈显著负相关(P<0.05),与pH值无显著相关性(P>0.05)。通过蛋白质组学鉴定出23种与TUFM相关的差异蛋白,通过基因本体论、京都基因与基因组百科全书通路分析发现,差异蛋白可通过多种途径参与能量代谢,进而介导细胞自噬;对差异蛋白和持水性指标进行Pearson相关性分析发现,有5种差异蛋白(ATP5F1D、EEF1A2、GSPT1、NDUFB5、SUCLG1)与持水性指标具有显著相关性(P<0.05、P<0.01)。分析可知,包括TUFM在内,共6种蛋白主要通过能量代谢和氧转运等途径正向或负向影响细胞自噬,从而影响肉的持水性。展开更多
The high conductivity of electrocatalyst can eliminate the Schottky energy barrier at the interface of heterogeneous phases during an electrocatalytic reaction and accelerate the rapid electron transfer to the catalyt...The high conductivity of electrocatalyst can eliminate the Schottky energy barrier at the interface of heterogeneous phases during an electrocatalytic reaction and accelerate the rapid electron transfer to the catalytic active center.Therefore,the electronic conductivity is a vital parameter for oxygen reduction reaction(ORR).Covalent triazine frameworks(CTFs)have shown great potential application as electrocatalysts in ORR with a merit of the diverse building blocks.However,the intrinsic low conductivity and high impedance of CTFs could be significant setbacks in electrocatalytic application.Herein,CTFs were constructed by introducing F and N co-modification for efficient 2e^(-)ORR.Compared with the pristine CTF,the co-presence of F,N could increase the conductivity obviously by 1000-fold.As a result,F-N-CTF exhibits enhanced catalytic performance of H_(2)O_(2)generation and selectivity towards reaction pathways.This work reveals the importance of conductivity optimization for CTFs and provides guidance for designing high conductivity non-metallic organic semiconductor catalysts for 2e^(-)ORR.展开更多
Photoinduced molecular oxygen activation is crucial for artificial photosynthesis.However,metal-free semiconductor photocatalysts with high activation efficiency are still lacking up to now.Herein,two isomorphic tris(...Photoinduced molecular oxygen activation is crucial for artificial photosynthesis.However,metal-free semiconductor photocatalysts with high activation efficiency are still lacking up to now.Herein,two isomorphic tris(triazolo)triazine-based covalent organic frameworks were successfully constructed under solvothermal conditions.And they possess high crystallinity,inherent porosity with large surface area and good stability.Strong electron donor-acceptor skeletons expand the visible light harvesting,also facilitate the charge separation and thus lead to their superior activity of photoinduced molecular oxygen activation including photosynthesis of tetrahydroquinolines and hydrogen peroxide.This work provides a way to improve the efficiency of molecular oxygen activation through the rational design of COFs,and also opens new avenues for the construction of highly active and metal-free photocatalysts toward sustainable solar-to-chemical energy conversion.展开更多
Converting CO_(2)and water into valuable chemicals like plant do is considered a promising approach to address both environmental and energy issues.Taking inspiration from the structures of natural leaves,we designed ...Converting CO_(2)and water into valuable chemicals like plant do is considered a promising approach to address both environmental and energy issues.Taking inspiration from the structures of natural leaves,we designed and synthesized a novel copper-coordinated covalent triazine framework(CuCTF)supported by silicon nanowire arrays on wafer chip.This marks the first-ever application of such a hybrid material in the photoelectrocatalytic reduction of CO_(2)under mild conditions.The Si@CuCTF6 heterojunction has exhibited exceptional selectivity of 95.6%towards multicarbon products(C_(2+))and apparent quantum efficiency(AQE)of 0.89%for carbon-based products.The active sites of the catalysts are derived from the nitrogen atoms of unique triazine ring structure in the ordered porous framework and the abundant Cu-N coordination sites with bipyridine units.Furthermore,through DFT calculations and operando FTIR spectra analysis,we proposed a comprehensive mechanism for the photoelectrocatalytic CO_(2)reduction,confirming the existence of key intermediate species such as*CO_(2)-,*=C=O,*CHO and*CO-CHO etc.This work not only provides a new way to mimic photosynthesis of plant leaves but also gives a new opportunity to enter this research field in the future.展开更多
3-Methylthio-5-hydroxy-1,2,4-triazine(1c)reacted with substituted benzenesulfonyl chloride to give 3-methylthio-5-oxy-1,2,4-triazin-6-yl pyridinium betaine(4)in anhydrous pyridine.But when NaOH/H_2O/CH_3COCH_3 or NaOH...3-Methylthio-5-hydroxy-1,2,4-triazine(1c)reacted with substituted benzenesulfonyl chloride to give 3-methylthio-5-oxy-1,2,4-triazin-6-yl pyridinium betaine(4)in anhydrous pyridine.But when NaOH/H_2O/CH_3COCH_3 or NaOH/CH_3OH were used as reactant and solvent,3-methylthio-4-substituted benzenesulfonyl-5-oxo-6-hydroxy-1,4,5,6-tetrahydro-1,2,4-triazine(6)or 1-tosyl-3-methylthio-5-oxo-6-methyloxy-1,4,5,6-tetrahydro-1,2,4-triazine(7)was obtained respectively.The above reactions show anomalous properties of nucleophilic attack on 6-carbon in 1,2,4-triazine ring.展开更多
Robust covalent organic frameworks(COFs)with abundant redox-active sites have attracted intense attention for organic cathode materials due to the ordered structure and excellent stability.Herein,a two-dimensional(2D)...Robust covalent organic frameworks(COFs)with abundant redox-active sites have attracted intense attention for organic cathode materials due to the ordered structure and excellent stability.Herein,a two-dimensional(2D)crystalline copper-porphyrin covalent triazine framework(CuBCPP-CTF)was synthesized via polycondensation of 5,15-bis(4-cyanophenyl)porphyrin(H2BCPP)and followed by post-copperization.The integration of copper-porphyrin moieties and triazine linkages provides two kinds of functional sites for outstanding Li+and PF6−ions storage.Electrochemical studies reveal a high discharge capacity of 232 mAh·g^(−1)at 200 mA·g^(−1)and high mid-point voltage(2.77 V vs.Li^(+)/Li),corresponding to an outstanding energy density of 601 Wh·kg^(−1).Density functional theory calculations and ex-situ characterizations disclose the intrinsic bipolar redox mechanism of metalloporphyrin for both PF6−and Li^(+)accommodation and p-type triazine units for PF_(6)^(−)storage.展开更多
Six fully optimized structures of the aza-calix[2]arene[2]-triazines/RDX supramo-lecular complexes have been obtained at the DFT-B3LYP/6-311＋＋G＊＊ level,and the corresponding intermolecular interactions have been i...Six fully optimized structures of the aza-calix[2]arene[2]-triazines/RDX supramo-lecular complexes have been obtained at the DFT-B3LYP/6-311＋＋G＊＊ level,and the corresponding intermolecular interactions have been investigated using the B3LYP,mPWPW91 and MP2 methods at the 6-311＋＋G＊＊ level,respectively.The natural bond orbital（NBO） and atoms in molecules（AIM） analyses have been performed to reveal the origin of interactions.To our interest,the result indicates that the strongest interaction is up to-22.34 kJ/mol after basis set superposition error（BSSE） and zero point energy（ZPE） correction at the MP2/6-311＋＋G＊＊ level.Furthermore,the intermolecular interactions between aza-calix[2]arene[2]-triazines with the substituted amidos and RDX are stronger than those of other complexes.Thus,the complexes with amidos can be used as the candidates to increase the stability of explosive and eliminate the explosive wastewater.展开更多
The Sluice Gate with Freight Carts is the earliest extant scroll in China that depicted a water mill.It was drawn during the early or middle Northern Song dynasty and was possibly a true portrayal of the West Water Mi...The Sluice Gate with Freight Carts is the earliest extant scroll in China that depicted a water mill.It was drawn during the early or middle Northern Song dynasty and was possibly a true portrayal of the West Water Mill Office.The copresence of a banquet scene of the Northern Song dynasty’s scholar-officials and a water mill both suggests a realistic reproduction of a specific scene and indicates the significance of the water mill as a cultural space.The Northern Song dynasty’s government-operated water mills were especially noticeable in the Capital Circuit京畿路,whose center was Dongjing东京.The basic development path of government-operated water mills in the inner and outer city of Dongjing was first from grain processing,which supplied the needs of the imperial palace,to tea processing,in which the governmental commercial capital also participated.Regarding city space and the use of water sources,the development spread from the north of the city to the south.Other prefectures outside Dongjing also had government-operated water mills—some brought income that could be used as official fiscal expenditure,including military expenditure,and were used to satisfy the need of local people’s livelihood,while some were used to serve the monopoly policy of tea and demonstrate the benevolent governance of local officials.In the Northern Song dynasty,the water mill was no longer merely a production site;rather,it was also a cultural space that integrated a natural background and artificial ingenuity.Closely related to the hosting of emperors and the garden making,sightseeing,feasting,and drinking of scholar-officials,along with the festival activities of locals,the water mill in the Northern Song dynasty was of great cultural significance.展开更多
Introduction 4,6-Diamino-1,2-dihydro-2,2-dimethyl-1-substituted-1,3,5-triazines (Ⅰ) are dihydrofolate reductase(DHFR) inhibitors, hence they possess the inhibition to the growth of bacteria and cancer cells. Baker’s...Introduction 4,6-Diamino-1,2-dihydro-2,2-dimethyl-1-substituted-1,3,5-triazines (Ⅰ) are dihydrofolate reductase(DHFR) inhibitors, hence they possess the inhibition to the growth of bacteria and cancer cells. Baker’s antifolate (Ⅱ) has shown promise as an antitumor agertt in clinical trials. The study of the structure-activity relationships of I shows that the inhibition to vertebrate DHFR is significantly influenced by the hydrophobicity of 1-substituent, i.e., the stronger the hydrophobicity of the 1-substituent, the more potent the inhibition of the compound to vertebrate DHFR.展开更多
Highly porous nitrogen-doped carbon materials were synthesized by the carbonization of a low-cost porous covalent triazine polymer, PCTP-3, which had been synthesized by the AlClcatalyzed FriedelCrafts reaction of rea...Highly porous nitrogen-doped carbon materials were synthesized by the carbonization of a low-cost porous covalent triazine polymer, PCTP-3, which had been synthesized by the AlClcatalyzed FriedelCrafts reaction of readily available monomers. The nature of the bond and structure of the resulting materials were confirmed using various spectroscopic methods, and the effects of KOH activation on the textural properties of the porous carbon materials were also examined. The KOH-activated porous carbon（aPCTP-3c） materials possessed a high surface area of 2271 mgand large micro/total pore volumes of 0.87/0.95 cmg, respectively, with narrower micropore size distributions than the porous carbon prepared without activation（PCTP-3c）. The aPCTP-3c exhibited the best COuptakes of 284.5 and 162.3 mg gand CHuptakes of 39.6 and 25.9 mg gat 273 and 298 K/1 bar, respectively, which are comparable to the performance of some benchmark carbon materials under the same conditions. The prepared materials exhibited high CO/Nselectivity and could be regenerated easily.展开更多
The title compound 4-oxo-1,2,4-triazino[4,5-a]benzimidazole（C9H6N4O,Mr = 186.18） has been synthesized and structurally characterized by IR,NMR and single-crystal X-ray diffraction. The crystal belongs to monoclinic,...The title compound 4-oxo-1,2,4-triazino[4,5-a]benzimidazole（C9H6N4O,Mr = 186.18） has been synthesized and structurally characterized by IR,NMR and single-crystal X-ray diffraction. The crystal belongs to monoclinic,space group P21/c,with a = 9.1530（18） ,b = 7.2260（14）,c = 12.604（3） ,β = 106.92（3） ,V = 797.5（3）A^3,Z = 4,Dc = 1.551 g/cm^3,λ（MoKa） = 0.71073,F（000） = 384,μ（MoKa） = 0.109 mm^-1,the final R = 0.0632 and wR = 0.1095. A total of 1444 unique reflections were collected,of which 767 with I 〉 2σ（I） were observed. The structure of the title compound is planar. In packing,the molecules are intersected to each other to form chains along three dimensions,together by intermolecular N-H…O and C-H…N hydrogen bonds. The whole structure is further stabilized by π…π interaction between two adjacent tricyclic ring systems,with the centroid-to-centroid distance of 3.369（4） A.展开更多
Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation...Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation.In this work,a metal free heterostructure of covalent triazine framework(CTF)and graphite carbon nitride(g‐C_(3)N_(4),abbreviated as CN)is applied in the CO_(2)photoreduction for the first time.Detailed characterization methods such as photoluminescence(PL)and time‐resolved PL(TR‐PL)decay are utilized to reveal the photo‐induced carries separating process on g‐C_(3)N_(4)/CTF(CN/CTF)heterostructure.The introduced CTF demonstrated a great boosting photocatalytic activity for CN,bringing about the transform rates of CO_(2)to CO reaching 151.1μmol/(g·h)with a 30 h stabilization time,while negligible CH_(4)was detected.The optimal CN/CTF heterostructure could more efficiently separate charges with a lower probability of recombination under visible light irradiation,which made the photoreduction efficiency of CO_(2)to CO be 25.5 and 2.5 times higher than that of CTF and CN,respectively.This investigation is expected to offer a new thought for fabricating high‐efficiency photocatalyst without metal in solar‐energy‐driven CO_(2)reduction.展开更多
Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ord...Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal nodes.To solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of ZIFs.Direct carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox pseudocapacitance.As proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell level.Our presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.展开更多
基金the financial support by the National Natural Science Foundation of China(Nos.22205124,52172206)Natural Science Foundation of Shandong province(Nos.ZR2021QB070,ZR2023QB110)+2 种基金Basic Research Projects for the Pilot Project of Integrating Science and Education and Industry of Qilu University of Technology(Shandong Academy of Sciences)(Nos.2023PY024,2023PX108)Special Fund for Taishan Scholars Projectthe Development Plan of Youth Innovation Team in Colleges and Universities of Shandong Province。
文摘The high conductivity of electrocatalyst can eliminate the Schottky energy barrier at the interface of heterogeneous phases during an electrocatalytic reaction and accelerate the rapid electron transfer to the catalytic active center.Therefore,the electronic conductivity is a vital parameter for oxygen reduction reaction(ORR).Covalent triazine frameworks(CTFs)have shown great potential application as electrocatalysts in ORR with a merit of the diverse building blocks.However,the intrinsic low conductivity and high impedance of CTFs could be significant setbacks in electrocatalytic application.Herein,CTFs were constructed by introducing F and N co-modification for efficient 2e^(-)ORR.Compared with the pristine CTF,the co-presence of F,N could increase the conductivity obviously by 1000-fold.As a result,F-N-CTF exhibits enhanced catalytic performance of H_(2)O_(2)generation and selectivity towards reaction pathways.This work reveals the importance of conductivity optimization for CTFs and provides guidance for designing high conductivity non-metallic organic semiconductor catalysts for 2e^(-)ORR.
文摘Photoinduced molecular oxygen activation is crucial for artificial photosynthesis.However,metal-free semiconductor photocatalysts with high activation efficiency are still lacking up to now.Herein,two isomorphic tris(triazolo)triazine-based covalent organic frameworks were successfully constructed under solvothermal conditions.And they possess high crystallinity,inherent porosity with large surface area and good stability.Strong electron donor-acceptor skeletons expand the visible light harvesting,also facilitate the charge separation and thus lead to their superior activity of photoinduced molecular oxygen activation including photosynthesis of tetrahydroquinolines and hydrogen peroxide.This work provides a way to improve the efficiency of molecular oxygen activation through the rational design of COFs,and also opens new avenues for the construction of highly active and metal-free photocatalysts toward sustainable solar-to-chemical energy conversion.
基金supported by Natural Science Foundation of Gansu Province(23JRRA745)the Fundamental Research Funds for the Central Universities(lzujbky2021-sp55).
文摘Converting CO_(2)and water into valuable chemicals like plant do is considered a promising approach to address both environmental and energy issues.Taking inspiration from the structures of natural leaves,we designed and synthesized a novel copper-coordinated covalent triazine framework(CuCTF)supported by silicon nanowire arrays on wafer chip.This marks the first-ever application of such a hybrid material in the photoelectrocatalytic reduction of CO_(2)under mild conditions.The Si@CuCTF6 heterojunction has exhibited exceptional selectivity of 95.6%towards multicarbon products(C_(2+))and apparent quantum efficiency(AQE)of 0.89%for carbon-based products.The active sites of the catalysts are derived from the nitrogen atoms of unique triazine ring structure in the ordered porous framework and the abundant Cu-N coordination sites with bipyridine units.Furthermore,through DFT calculations and operando FTIR spectra analysis,we proposed a comprehensive mechanism for the photoelectrocatalytic CO_(2)reduction,confirming the existence of key intermediate species such as*CO_(2)-,*=C=O,*CHO and*CO-CHO etc.This work not only provides a new way to mimic photosynthesis of plant leaves but also gives a new opportunity to enter this research field in the future.
基金Director of the project supported by National Natural Science foundation of China.
文摘3-Methylthio-5-hydroxy-1,2,4-triazine(1c)reacted with substituted benzenesulfonyl chloride to give 3-methylthio-5-oxy-1,2,4-triazin-6-yl pyridinium betaine(4)in anhydrous pyridine.But when NaOH/H_2O/CH_3COCH_3 or NaOH/CH_3OH were used as reactant and solvent,3-methylthio-4-substituted benzenesulfonyl-5-oxo-6-hydroxy-1,4,5,6-tetrahydro-1,2,4-triazine(6)or 1-tosyl-3-methylthio-5-oxo-6-methyloxy-1,4,5,6-tetrahydro-1,2,4-triazine(7)was obtained respectively.The above reactions show anomalous properties of nucleophilic attack on 6-carbon in 1,2,4-triazine ring.
基金supported by the National Natural Science Foundation of China(Nos.22261132512,22235001,22175020,and 22131005)Guizhou Provincial Key Laboratory Platform Project(No.ZSYS[2025]008)+1 种基金Talent Program of Guizhou University(No.[2024]11)Xiaomi Young Scholar Program,and University of Science and Technology Beijing.
文摘Robust covalent organic frameworks(COFs)with abundant redox-active sites have attracted intense attention for organic cathode materials due to the ordered structure and excellent stability.Herein,a two-dimensional(2D)crystalline copper-porphyrin covalent triazine framework(CuBCPP-CTF)was synthesized via polycondensation of 5,15-bis(4-cyanophenyl)porphyrin(H2BCPP)and followed by post-copperization.The integration of copper-porphyrin moieties and triazine linkages provides two kinds of functional sites for outstanding Li+and PF6−ions storage.Electrochemical studies reveal a high discharge capacity of 232 mAh·g^(−1)at 200 mA·g^(−1)and high mid-point voltage(2.77 V vs.Li^(+)/Li),corresponding to an outstanding energy density of 601 Wh·kg^(−1).Density functional theory calculations and ex-situ characterizations disclose the intrinsic bipolar redox mechanism of metalloporphyrin for both PF6−and Li^(+)accommodation and p-type triazine units for PF_(6)^(−)storage.
文摘Six fully optimized structures of the aza-calix[2]arene[2]-triazines/RDX supramo-lecular complexes have been obtained at the DFT-B3LYP/6-311＋＋G＊＊ level,and the corresponding intermolecular interactions have been investigated using the B3LYP,mPWPW91 and MP2 methods at the 6-311＋＋G＊＊ level,respectively.The natural bond orbital（NBO） and atoms in molecules（AIM） analyses have been performed to reveal the origin of interactions.To our interest,the result indicates that the strongest interaction is up to-22.34 kJ/mol after basis set superposition error（BSSE） and zero point energy（ZPE） correction at the MP2/6-311＋＋G＊＊ level.Furthermore,the intermolecular interactions between aza-calix[2]arene[2]-triazines with the substituted amidos and RDX are stronger than those of other complexes.Thus,the complexes with amidos can be used as the candidates to increase the stability of explosive and eliminate the explosive wastewater.
文摘The Sluice Gate with Freight Carts is the earliest extant scroll in China that depicted a water mill.It was drawn during the early or middle Northern Song dynasty and was possibly a true portrayal of the West Water Mill Office.The copresence of a banquet scene of the Northern Song dynasty’s scholar-officials and a water mill both suggests a realistic reproduction of a specific scene and indicates the significance of the water mill as a cultural space.The Northern Song dynasty’s government-operated water mills were especially noticeable in the Capital Circuit京畿路,whose center was Dongjing东京.The basic development path of government-operated water mills in the inner and outer city of Dongjing was first from grain processing,which supplied the needs of the imperial palace,to tea processing,in which the governmental commercial capital also participated.Regarding city space and the use of water sources,the development spread from the north of the city to the south.Other prefectures outside Dongjing also had government-operated water mills—some brought income that could be used as official fiscal expenditure,including military expenditure,and were used to satisfy the need of local people’s livelihood,while some were used to serve the monopoly policy of tea and demonstrate the benevolent governance of local officials.In the Northern Song dynasty,the water mill was no longer merely a production site;rather,it was also a cultural space that integrated a natural background and artificial ingenuity.Closely related to the hosting of emperors and the garden making,sightseeing,feasting,and drinking of scholar-officials,along with the festival activities of locals,the water mill in the Northern Song dynasty was of great cultural significance.
基金Supported by the National Natural Science Foundation of China
文摘Introduction 4,6-Diamino-1,2-dihydro-2,2-dimethyl-1-substituted-1,3,5-triazines (Ⅰ) are dihydrofolate reductase(DHFR) inhibitors, hence they possess the inhibition to the growth of bacteria and cancer cells. Baker’s antifolate (Ⅱ) has shown promise as an antitumor agertt in clinical trials. The study of the structure-activity relationships of I shows that the inhibition to vertebrate DHFR is significantly influenced by the hydrophobicity of 1-substituent, i.e., the stronger the hydrophobicity of the 1-substituent, the more potent the inhibition of the compound to vertebrate DHFR.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(grant number:2015042434)the support by the Korea Research Fellowship Program(grant number:2017H1D3A1A02013620)
文摘Highly porous nitrogen-doped carbon materials were synthesized by the carbonization of a low-cost porous covalent triazine polymer, PCTP-3, which had been synthesized by the AlClcatalyzed FriedelCrafts reaction of readily available monomers. The nature of the bond and structure of the resulting materials were confirmed using various spectroscopic methods, and the effects of KOH activation on the textural properties of the porous carbon materials were also examined. The KOH-activated porous carbon（aPCTP-3c） materials possessed a high surface area of 2271 mgand large micro/total pore volumes of 0.87/0.95 cmg, respectively, with narrower micropore size distributions than the porous carbon prepared without activation（PCTP-3c）. The aPCTP-3c exhibited the best COuptakes of 284.5 and 162.3 mg gand CHuptakes of 39.6 and 25.9 mg gat 273 and 298 K/1 bar, respectively, which are comparable to the performance of some benchmark carbon materials under the same conditions. The prepared materials exhibited high CO/Nselectivity and could be regenerated easily.
基金sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘The title compound 4-oxo-1,2,4-triazino[4,5-a]benzimidazole（C9H6N4O,Mr = 186.18） has been synthesized and structurally characterized by IR,NMR and single-crystal X-ray diffraction. The crystal belongs to monoclinic,space group P21/c,with a = 9.1530（18） ,b = 7.2260（14）,c = 12.604（3） ,β = 106.92（3） ,V = 797.5（3）A^3,Z = 4,Dc = 1.551 g/cm^3,λ（MoKa） = 0.71073,F（000） = 384,μ（MoKa） = 0.109 mm^-1,the final R = 0.0632 and wR = 0.1095. A total of 1444 unique reflections were collected,of which 767 with I 〉 2σ（I） were observed. The structure of the title compound is planar. In packing,the molecules are intersected to each other to form chains along three dimensions,together by intermolecular N-H…O and C-H…N hydrogen bonds. The whole structure is further stabilized by π…π interaction between two adjacent tricyclic ring systems,with the centroid-to-centroid distance of 3.369（4） A.
文摘Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation.In this work,a metal free heterostructure of covalent triazine framework(CTF)and graphite carbon nitride(g‐C_(3)N_(4),abbreviated as CN)is applied in the CO_(2)photoreduction for the first time.Detailed characterization methods such as photoluminescence(PL)and time‐resolved PL(TR‐PL)decay are utilized to reveal the photo‐induced carries separating process on g‐C_(3)N_(4)/CTF(CN/CTF)heterostructure.The introduced CTF demonstrated a great boosting photocatalytic activity for CN,bringing about the transform rates of CO_(2)to CO reaching 151.1μmol/(g·h)with a 30 h stabilization time,while negligible CH_(4)was detected.The optimal CN/CTF heterostructure could more efficiently separate charges with a lower probability of recombination under visible light irradiation,which made the photoreduction efficiency of CO_(2)to CO be 25.5 and 2.5 times higher than that of CTF and CN,respectively.This investigation is expected to offer a new thought for fabricating high‐efficiency photocatalyst without metal in solar‐energy‐driven CO_(2)reduction.
基金Ministry of Trade,Industry&Energy of Korea,Grant/Award Number:RS‐2022‐00155717National Research Foundation of Korea,Grant/Award Numbers:2020H1D3A1A04081472,2022M3J1A1054323。
文摘Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal nodes.To solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of ZIFs.Direct carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox pseudocapacitance.As proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell level.Our presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.
