紫精类电致变色材料的制备和机理

1,1'-二取代4,4'-联吡啶盐通常称作紫精(viologen),紫精以及接有紫精基团的聚合物（polyviologen）有优异的电致和光致变色性能,在新一代电致变色器件、显示器件和智能窗等方面有很好的应用前景。文章综述了紫精和紫精聚合物的制备、结构与性能、电致变色机理、功能器件设计以及在化学合成、纳米功能符合等方面的研究进展,并提出例如今后的重要研究方向。     

烯烃取代的紫罗精合成及全固态电致变色器件

合成了2种烯烃取代的紫罗精分子,通过核磁、红外和紫外测试技术对其结构进行了确证。循环伏安表明,它们都有2个明显的可逆氧化还原峰;并以PEO胶体聚电解质为离子导电层组装出了基于所合成化合物,低能耗、无辐射的全固态电致变色器件,总厚度约2.35mm,同溶液型电致变色器件相比较,全固态化可以提高器件在变色-褪色和开路延时记忆等方面的性能,且固态电致变色器件制作工艺相对简单,便于规模化生产。经优化后制作的电致变色器件施加1.1～3V的电压可产生明显的蓝色或紫色,断电后开路延时记忆可以达到3d。实验测试出大多数器件响应时间小于50ms,循环次数在百万次以上,主要性能指标已经达到电子墨水的显示要求。     

磷腈-紫精聚合物的合成与电致变色性能

以六氯环三磷腈作为核心、 紫精为电致变色活性基, 合成了一种新型有机-无机杂化电致变色材料——六(1-乙基-4,4'-联吡啶-甲基苯氧基)环三磷腈(PHV ²⁺). 通过傅里叶变换红外光谱(FTIR)、 X射线衍射(XRD)及核磁共振氢谱( ¹H NMR)表征了PHV ²⁺的结构. 优良的水溶性使得该化合物可以通过简单的方法构造一个以聚乙烯醇(PVA)为凝胶基质的电致变色水凝胶, 具有成本低廉及无毒害的优点. 以氟掺杂氧化锡(FTO)涂层玻璃作为电极材料, PHV ²⁺作为电致变色材料制备了PHV ²⁺/PVA/KCl电致变色器件(PHV ²⁺/PVA/KCl ECD). 该电致变色器件在2.1 V电压下由淡黄色变为紫色, 颜色变化明显, 并且该颜色变化可以循环500次; 器件在526 nm处的光学对比度达到62.19%. 良好的电致变色性质使该化合物在电致变色器件方面具有潜在应用价值.     

获得高性能电致变色薄膜的ITO表面修饰方法

氧化铟锡玻璃(ITO)以其优良的导电性能和透过率以及相对低的反应活性使其在显示器和电致变色器件中有广泛的应用. 然而, ITO表面的金属氧化物基团也带来了一些问题, 如通过物理方法沉积的电致变色薄膜易从ITO基底上脱离, 从而降低器件寿命, 此种问题在使用液体电解质时显得尤为突出. 为此, 我们利用有机酸小分子对ITO基底表面进行修饰, 继而利用电化学沉积的方法制备聚3,4-(2,2-二甲基丙烯二氧基)噻吩电致变色薄膜. XPS结果表明基底与修饰物间以化学键结合, 超声波处理可以看出电致变色薄膜在修饰后的基底上有更好的稳定性. 本研究提供了一种简单易行的方法来获得高性能的高分子电致变色薄膜.     

金属-超分子聚合物的合成及其多色电致变色器件

本文合成了一种多齿配体化合物——1,4-双(2,2′:6′,2′′-三联吡啶-4′-基)苯及其Fe/Ru金属-超分子聚合物——Poly Fe和Poly Ru,同时以喷涂在ITO导电玻璃上的Fe/Ru金属-超分子聚合物膜为工作电极、0.1 mol/L Li Cl O4水溶液为电解质,并添加K_3Fe(CN)_6为电化学互补材料,制作了系列电致变色器件.由Poly Fe和Poly Ru的组合,可以得到从Poly Fe的蓝紫色渐变到Poly Ru橙红色的彩色薄膜及其多色电致变色器件,器件响应速度快(2 s),褪色电压0.9~1.2 V,着色电压0 V,最大光学对比度约57%.添加K_3Fe(CN)_6后,器件的寿命得到极大提高.     

三苯胺类自供能电致变色材料合成及器件开发

设计并合成了一种新型三苯胺衍生物: (4-((4-(二甲基氨基)苯基)(苯基)氨基)苄基)膦酸, 并研究了它的光谱电化学性质和光伏性质. 光谱电化学谱图表明该化合物具有电致变色性能: 通过施加不同电压, 该化合物薄膜可以在透明态和着色态之间转换, 且在629 nm处透过率对比度达到最大, 为64.2%. 由该材料组装成的自供能电致变色器件具有光伏性能, 光电转化效率可以达到0.32%. 和传统的光电变色器件相比, 该新型器件具有结构简单、制备成本低廉、绿色环保等特点, 预计在建筑、汽车、显示器等领域将有广泛的应用.     

微波作用下2,3,5-三取代噻吩的合成及光电性质的研究

含硫芳香化合物可用于有机半导体、电致发光器件,电致变色器件和场效应管。噻吩是一种富电子的五元芳杂环,电子的流动性大,有望成为较好的电子注入／传输材料。我们利用微波辐射在噻吩环的2,3,5位引入了芳基,产物的结构经元素分析、质谱、^1H NMR表征,采     

多功能变色材料紫精化合物的合成与可视变色传感

变色材料广泛应用于航空航天、能源化工、日用食品、国防及科学研究等诸多领域。紫精化合物(N-取代的-4,4’-联吡啶季铵盐,V)能在外界光、电、热等激发下表现出多样的变色性质,是一类重要的变色材料。本文将紫精变色材料的科学前沿成果引入本科实验教学,创新设计了一个面向本科低年级学生开设的大学化学基础实验。该实验以激发学生的好奇心与探索欲,培养学生对化学的学习兴趣,开阔学生的视野,提高学生对化学的认知为目的,合成了邻羟基苯乙酮取代基紫精,研究了它的溶剂化显色、热致变色及对NH3的可逆显色反应。实验的特点是反应原料简单易得、合成方法简便、反应时间短、产率高、实验操作安全可靠、变色现象均可以不借助仪器而裸眼直接观察、变色过程快速且灵敏。这些优势为实验项目的应用与推广提供了极大的便利。     

基于紫精组分构筑的三种光致变色共晶体

在碱性条件下,将1,2,4,5-均苯四甲酸(H4BTEC)与过渡金属离子配位,并引入中性紫精组分1-羧乙基-4,4′-联吡啶(CEbpy),构筑了3个同构共晶体[M(H₂O)_5(BTEC)_0.5]·(CEbpy)(M=Mn(1)、Zn(2)、Co(3))。在紫外灯照射下,3个化合物都发生明显的光致变色现象,这归因于光诱导的电子转移并产生了紫精自由基。同时,在加热的情况下,化合物3还表现出不可逆的失水致变色行为,而化合物1和2则没有。我们讨论了金属离子对变色行为的影响。     

Ag/WO3纳米复合膜的制备及其电致变色性质和器件的研究

通过真空镀膜方法制备的纳米Ag薄膜均匀致密, 表面光滑. 然后通过电化学方法在Ag纳米薄膜上沉积一层三氧化钨(WO3), 制备纳米Ag/WO3复合膜. 并在此基础上构筑五层式玻璃/ITO/纳米Ag-WO3复合膜/固态电解质/聚(3-甲基噻吩)/ITO/玻璃电致变色器件. 实验结果表明, 与传统的WO3膜相比, 纳米Ag/WO3复合膜具有更好的电化学活性、更高的对比度、更短的响应时间, 以及更好的稳定性. 由该复合膜组装的电致变色器件工艺简单, 电致变色性能良好.     

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.