纳米纤维素/聚3,4-乙撑二氧噻吩复合薄膜的制备及电致变色性能

以棉浆粕为原料,采用硫酸溶胀结合超声波处理的方法制备了纳米纤维素(NC).在纳米纤维素的水分散液中加入3,4-乙撑二氧噻吩单体,以过硫酸铵为氧化剂,采用原位化学氧化法制得了纳米纤维素/聚3,4-乙撑二氧噻吩(NC/PEDOT)纳米复合物.对NC和NC/PEDOT复合物进行扫描电镜、透射电镜和红外光谱分析.将纳米复合物的水分散液滴涂在氧化铟锡(ITO)玻璃表面形成复合薄膜,考察不同纳米纤维素含量对NC/PEDOT复合薄膜电致变色性能的影响.结果表明,NC呈棒状,平均直径为20 nm,长度为100~300nm;NC/PEDOT复合物中PEDOT均匀包覆在NC表面形成核壳结构,平均直径为30 nm;复合薄膜中当NC含量为60%时,其电致变色性能最好,具有最高的对比度(24.4%),最短的响应时间(1 s),最高的着色效率(51.8 cm~2/C).     

反向胶束法制备聚3,4-乙烯二氧噻吩纳米粒子的光电性能和热稳定性

采用聚合和掺杂同时进行的反向胶束体系制备了粒径分散较小的聚3,4-乙烯二氧噻吩(PEDOT)纳米粒子, 利用紫外-可见光光谱(UV-Vis)、X射线衍射(XRD)和扫描电子显微镜(SEM)等分析方法对纳米粒子进行了表征. 实验结果发现, 氧化剂用量、超声处理、聚合温度及掺杂程度对PEDOT纳米粒子的形貌、电性能及热稳定性有不同程度的影响. 根据实验结果对反向胶束法制备PEDOT纳米粒子过程进行优化发现, 在PEDOT纳米粒子聚合过程中, 甲基苯磺酸有效掺杂浓度约为0.17 mol/L时, PEDOT链的取向最规则, 在6.7°, 12.7°, 25°出现衍射峰, 掺杂剂的有效掺杂使得纳米粒子中分子链的取向不同, 并可以获得较高的电导率(>100 S/cm)的PEDOT纳米粒子, 当粒子的尺寸小于20 nm后电导率降低; 热失重法(TG)分析结果表明, PEDOT纳米粒子的热稳定性比普通块材好, 掺杂剂浓度对纳米粒子的热稳定性有一定影响.     

纳米硒/多壁碳纳米管复合材料的制备及其电化学性能

经混酸纯化处理的多壁碳纳米管(MWCNTs)负载纳米硒(Nano-Se0)制备纳米硒/多壁碳纳米管复合材料(Nano-Se0/MWCNTs,简称1),其结构经IR,TEM和SEM表征.以Fe(CN)4-/3-6 为探针离子,采用循环伏安法和电化学阻抗法考察了1的电化学性能.     

导电共聚物衍化新策略制备硫、氮共掺杂碳纳米管及其对改善PtCu纳米晶分散性与甲醇电催化氧化的促进作用

有效调控碳纳米材料的几何和电子结构的协同效应和缺陷是获得优良电化学性能的关键.然而,如何设计一种具有优势结构的杂化材料及对其电催化机理的认识尚不清楚.本文提出了一种聚(3,4-乙撑二氧噻吩)/聚苯胺导电共聚物热解策略来制备S和N共掺杂多壁碳纳米管(MWCNTs),发现改变前驱体溶液中两种单体的比例可以调控掺杂MWCNT...     

基于AuNP/PEI/MWCNTs构筑的双酚A电化学传感器

制备了一种基于AuNP/PEI/MWCNTs纳米复合材料的电化学传感器,并通过循环伏安法(CV)测定痕量的双酚A(BPA).AuNP紧密地锚固在管状交联的聚乙烯亚胺均匀包裹的多壁碳纳米管(MWCNTs)的空隙中形成AuNP/PEI/MWCNTs.利用场发射扫描电子显微镜和粉末X射线衍射对AuNP/PEI/MWCNTs纳...     

聚乙撑二氧噻吩的导电性及现场ESR响应的研究

聚乙撑二氧噻吩(PEDOT)因为具有很高的稳定性和导电性，近年来受到了广泛 的注意并开始在许多方面得到实际应用．电化学聚合方法具有操作简便、易于控制 等优点．本文采用恒电位电化学聚合方法，在水溶液中Pt电极上制备了聚乙撑二氧 噻吩．研究了单体浓度、支持电解质种类、聚合电位等因素对聚合得到的PEDOT膜 导电性的影响．首次运用电化学现场ESR技术研究了水溶液中PEDOT膜的ESR响应， 结合电化学现场的膜电阻测量研究了PEDOT膜的导电性随所加电位的变化规律．结 果表明，PEDOT膜随不同电位的导电性的变化规律符合极化子—双极化子理论．     

聚乙撑二氧噻吩/二氧化锰纳米复合物的界面聚合制备及其电化学性能

采用界面聚合法制备聚3,4-乙撑二氧噻吩/二氧化锰(PEDOT/MnO2)纳米复合物. 通过红外(IR)光谱、X射线衍射(XRD)、BET比表面积、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对样品进行表征. 结果表明, 产物是具有丰富的多孔孔道结构的无定型纳米材料, 孔径主要分布在5-25 nm范围内, 比表面积可达98 m2·g-1. 同时用循环伏安(CV)、恒流充放电和交流阻抗(EIS)等电化学测试表明, 在0.5 mol·L-1 Na2SO4溶液中, -0.2 - 0.8 V(vs SCE)的电化学窗口下, PEDOT/MnO2纳米复合物显示出良好的电化学性能, 当电流密度为0.5 A·g-1时, 所制备的PEDOT/MnO2单电极比容量达196.3 F·g-1, 500次循环后样品放电比容量保持90%左右.     

基于纳米聚3,4-乙撑二氧噻吩的导电复合材料制备及其在印刷电子中的应用

<正>印刷技术作为传统的加成制造工艺(Additive Process)具有低成本、低能耗、柔性化、绿色环保,并且适合大面积卷对卷(Roll-2-Roll)生产等优点。近年来,印刷有机发光二极管(OLED)、有机光伏电池(OPV)、有机薄膜晶体管(OTFT)、有机传感器等技术均成为研究热点。共轭导电聚合物聚3,4-乙撑二氧噻吩(PEDOT)具有电导率高、光学透过性好、热稳定性好等特点,经掺杂后能在水中形成均匀稳定的     

碳纳米管聚(3′,4′-亚乙基二氧-2,2′:5′,2″-三噻吩)复合材料的制备及其电化学性能研究

通过Stille反应合成了3′,4′-亚乙基二氧-2,2′:5′,2″-三噻吩(TET),并以其作为单体,采用化学氧化原位聚合方法在碳纳米管(CNT)的表面包覆新型聚(3′,4′-亚乙基二氧-2,2′:5′,2″-三噻吩)(PTET),制备了PTET-CNT纳米复合材料.通过TEM、SEM和IR对其进行了表征,并利用循环伏安、交流阻抗、恒电流充放电等电化学测试方法,比较研究了复合材料以及碳纳米管在0.1 mol/L四乙基四氟硼酸铵(Et4NPF4)的乙腈溶液中的电化学行为.实验结果表明,在电流密度为3 mA/cm2时,PTET-CNT复合材料的比电容为86 F/g,比原碳纳米管比电容20 F/g提高了3.3倍.基于这种复合材料的电容器的能量密度达到2.02 Wh/kg.     

PEDOT基光子晶体的制备及其电致变色性能研究

采用改进的Stöber法合成了单分散SiO₂微球, 通过垂直沉积组装成蛋白石结构光子晶体. 再使用电化学法在组装的SiO₂微球表面生成聚(3,4-乙撑二氧噻吩)(PEDOT), 得到核-壳结构的SiO₂@PEDOT光子晶体复合膜. 测试了SiO₂@PEDOT光子晶体薄膜的反射光谱、循环伏安曲线、多电位紫外反射光谱、对比度及响应时间等光学、电化学及电致变色性能. 结果表明, 该光子晶体薄膜在变色时颜色亮丽, 其色差值(26.82)比纯PEDOT薄膜(18.07)提高很多, 并且最大对比度可达39.8%, 高于纯PEDOT薄膜的27.4%, 同时响应时间变快. 此实验结果说明将光子晶体结构引入导电聚合物中, 能够提高其电致变色性能.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.