搜索到1563篇“ PYRIDYL“的相关文章
Peculiarities of Ethylene Polymerization Reactions with Bis(imino)pyridyl Complexes of CoCl_(2) and FeCl_(2)被引量:1
2024年
The article describes ethylene polymerization reactions with transition metal catalysts based on complexes of CoCl_(2) and FeCl_(2) with an N,N,N-tridentate ligand 2,6-bis[1-(2,6-dimethylphenylimino)ethyl]pyridine. The complexes are converted into polymerization catalysts by reacting them either with polymethylalumoxane (MAO) or with a combination of Al(C2H5)2Cl and Mg(C4H9)2 at an [Al]:[Mg] ratio of ~3. Both MAO-activated complexes readily polymerize ethylene at 35 ℃ with the formation of linear, low molecular weight polymers with a narrow molecular weight distribution. The same complexes, when activated with the Al(C2H5)2Cl-Mg(C4H9)2 combination, form multi-center catalysts and generate polyethylenes with a broad molecular weight distribution.
Laura A.RishinaYury V.KissinSvetlana S.LalayanArtem A.AntonovVadim G.KrasheninnikovAlexander A.Gulin
A homopolymolybdate-supported plate-like 2D cobalt network constructed from a new pyrazole-amide-pyridyl ligand: highly electrochemical activity in both capacitive performance and the detection of Cr(Ⅵ)被引量:1
2024年
By employing a new semi-rigid pyrazole-amide-derived bis(pyridyl)ligand[N,N'-bis(4-picolylamine)-1-hydropyrazole(4-dpap)],a new homopolymolybdate-based two-dimensional(2D)plate-like complex[Co(4-dpap)(H_(2)O)(β-Mo_(8)O_(2)6)1/2](1)has been prepared under solvothermal condition and structurally characterized.Theβ-Mo_(8)anions are fi xed between the 2D metal–organic networks[Co(4-dpap)(H_(2)O)]n 2n+via hydrogen-bonding interaction.Complex 1 possesses satisfactory specifi c capacitance of 1512.4 F·g^(−1)(current density:1 A·g^(−1))and good cycling stability(90.8%after 1000 cycles).Moreover,1 represents a promising amperometric sensor for measurement of Cr(Ⅵ)with low detection limit(0.042μmol·L^(−1))and high durability.The insertion ofβ-Mo_(8)anions between the unique 2D metal−organic networks improves the active area of polyoxometalates,which further promotes electrochemical performance.
Xiu-Li WangYong-Zhen ChenZhi-Han ChangYu-Chun LinJing-Yi Ma
关键词:SUPERCAPACITOR
悬浮聚合法制备多孔吡啶基阴离子交换树脂及其表征
2024年
采用悬浮聚合法成功制备了多孔吡啶基弱碱性阴离子交换树脂(4VP-DVB),通过季铵化制备了强碱性阴离子交换树脂(4VP-DVBQ)。对两种树脂采用粒径分析、扫描电子显微镜(SEM)、比表面积测试(BET)、傅立叶变换红外吸收光谱(FT IR)以及热重分析(TGA)等进行了表征,并对成本进行了评估。实验结果表明:两种树脂都具有规则的球形结构,粒径分布于40~130μm,具备多孔性结构且平均孔径达15 nm;TGA结果表明,两种树脂有较好的热稳定性能,起始分解温度在200℃以上。
胡崇庆韩刚陈彦良
关键词:悬浮聚合法
钯催化邻-碳硼烷基吡啶卤化物交叉偶联合成邻-碳硼烷基联芳、氨基吡啶和炔基吡啶衍生物
2024年
发展了一种钯催化邻-碳硼烷基吡啶卤化物与(杂)芳基硼酸交叉偶联反应合成邻-碳硼烷基联芳衍生物的高效方法.该方法具有条件温和、官能团兼容性好等特点.此外,通过Buchwald-Hartwig反应及Sonogashira反应分别合成了邻-碳硼烷基氨基吡啶和炔基吡啶类化合物.该类杂环芳基碳硼烷衍生物在发光材料以及药物等领域具有应用潜力.
罗东红李平陈志才杨佳怡孙梦凡陆居有
关键词:碳硼烷交叉偶联钯催化
A hydrogen-bonded organic framework containing fluorescent carbazole and responsive pyridyl units for sensing organic acids
2024年
Hydrogen-bonded organic frameworks(HOFs)are a promising candidate for optical sensing,but the lack of effective design strategies poses significant challenges to the construction of HOFs for organic acid sensing.In this work,the first HOF for organic acid sensing is reported by constructing a multiplepyridine carbazole-based dense HOF,namely HOF-FJU-206,from a tripyridine-carbazole molecular 3,6-bis(pyridin-4-yl)-9-(4-(pyridin-4-yl)phenyl)-9H-carbazole(CPPY)with carbazole center for luminescence,pyridyl sites for its responsive of hydrogen proton,and narrow channels in the dense framework for the diffusion of hydrogen protons.HOF-FJU-206 exhibits differential responsively fluorescence sensing and recovery properties to formic,acetic,and propionic acids with different molecular sizes and p Kavalue(acid dissociation constant).The dissociation degree of various acids can be determined by analyzing the slope of changes in both peak wavelength and intensity of in-situ fluorescence,which easily enables the dual-corrective recognition of different acids.The varying degree of protonation at pyridine sites is proved to be the reason for differential sensing of various acids,as demonstrated by1H NMR spectra,X-ray photoelectron spectroscopy(XPS)characterization,and modeling studies.
Liangji ChenZhen YuanFudong FengXin ZhouZhile XiongWuji WeiHao ZhangBanglin ChenShengchang XiangZhangjing Zhang
The role of singlet oxygen and hydroxyl radical in the photobleaching of meso-substituted cationic pyridyl porphyrins in the presence of folic acid被引量:1
2024年
Using a photosensitizer(PS),light,and oxygen,photodynamic therapy creates cytotoxic reactive oxygen species,such as singlet oxygen(1O2),that kill cancer cells.Many cancer cell lines have up to 300 times more folic acid receptors than healthy cells.Therefore,folic acid is often used to improve selectivity of PSs.Photobleaching poses a disadvantage for PSs.In this paper,we have studied the photoinduced changes of meso-substituted cationic pyridyl porphyrins in the presence of folic acid using uorescence and absorption spectroscopy.In this work,it was demonstrated that L-histidine,which is a 1O2 quencher,and D-mannitol,which is a hydroxyl radical quencher,can reduce photobleaching of cationic porphyrins and their interaction products with FA.This implies both singlet oxygen and hydroxyl radicals are involved in photobleaching.Additionally,our study revealed certain important features of the photobleaching of cationic porphyrins in the presence of folic acid.
Lusine MkrtchyanTorgom SeferyanMarina ParkhatsSergei LepeshkevichBoris DzhagarovGagik ShmavonyanElena TuchinaValery TuchinGrigor Gyulkhandanyan
关键词:HISTIDINEMANNITOL
O-乙基-S-乙基-O-(3,5,6-三氯-2-吡啶基)磷酸酯的合成
2024年
为了研究毒死蜱中转位杂质的含量,及减少毒死蜱合成中该杂质的形成,探究合成O-乙基-S-乙基-O-(3,5,6-三氯-2-吡啶基)磷酸酯的最优工艺参数。以三氯化磷和乙醇为原料,经取代、氨化、缩合、酰化和缩合五步反应合成目标产物。取代、氨化、缩合、酰化和缩合的收率分别为82.3%、90.3%、96.0%、97.1%和96.7%,总收率达到67.0%。实验结果经色谱分析表明:合成的产物气液相面积归一化均可达到98%。
田俊杰孙在臣张斌铨姚广禹陈涛朱恒营
关键词:乙基氯化物
吡啶基咪唑衍生物合成及其在有机可焊保护剂中的应用
2024年
[目的]咪唑及其衍生物的水溶性较差,制备的有机可焊保护剂(OSP)不稳定,易出现浑浊或析出固体物质。[方法]以3,5-二氯吡啶-4-甲醛与1-苯基-1,2-丙二酮为原料,合成了2-(2,6-二氯-4-吡啶基)-4-苯基-5-甲基咪唑(DPN),将其用作OSP的主成膜物。使用气相色谱-质谱联用仪(GC-MS)、核磁共振仪(NMR)、傅里叶变换红外光谱仪(FT-IR)表征其结构。通过浸泡腐蚀、电化学分析、热重分析、回流焊测试、边缘浸焊测试等手段对DPN成膜之后的耐蚀性、耐热性和焊接性进行了研究。[结果]制备的DPN水溶性良好,对提高OSP的稳定性有利。DPN在铜表面的有效吸附和成膜能够很好地保护铜面不被腐蚀,赋予铜面优良的耐热性和可焊性。[结论]DPN可用作印制电路板有机可焊保护剂的主成膜物。
杨泽张桂敏雷家珩何康马斯才
关键词:印制电路板耐蚀性可焊性
基于二亚胺吡啶配体的铁系乙烯齐聚催化剂研究进展
2024年
乙烯齐聚技术是制备全范围α-烯烃产品的最重要的途径。近年来,铁系乙烯齐聚催化剂研究取得了蓬勃的发展,中石化抓住此机遇,自主研发了邻菲咯啉铁系催化剂和成套技术并成功用于工业化生产中。尽管取得了重大突破,但是进一步优化乙烯齐聚催化剂,提高催化剂的稳定性、活性和选择性仍具有重要的基础研究意义和应用价值且面临着相当的挑战。基于此,我们回顾了经典的二亚胺吡啶铁系催化剂的发展历史,重点梳理了配体取代基的电子效应和空间位阻对催化性能的影响,以期推动新型、高效铁系乙烯齐聚催化剂的理性设计和开发应用。
隋军龙赵晓刘珺
关键词:乙烯齐聚Α-烯烃构效关系
一锅法制备1-吡啶基-3-哌啶-4-甲酸的合成研究
2024年
N杂环类分子是一类重要的医药切块分子,多用作多肽类医药分子的合成原料中间体。报道了一种N杂环类分子1-吡啶基-3-哌啶-4-甲酸新的合成方法。高压反应釜依次加入3-溴吡啶、4-哌啶甲酸乙酯、碳酸钾、N-甲基吡咯烷酮,反应釜密封好,升温至180℃,压力保持0.5MPa,液质监测反应,反应72h,原料反应完毕。将反应体系冷却至室温后抽滤,滤饼用甲醇打浆后再次抽滤,将滤液浓缩后再甲醇重结晶得黄色粉末,产率最高可达46%。该合成方法,碱性高压条件,一锅法得到目标化合物,极大地降低了工业成本,且后处理方法简单且收率高,具有工业化生产前景。
陈艳君杨伟群杨伟群
关键词:碳酸钾N-甲基吡咯烷酮甲醇

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