钾离子调控的1,5-萘基桥联双冠醚的

报道了萘基桥联双苯并15-冠-5的合成, 研究了K^＋调控的双冠醚自组装过程以及伴随的独特荧光行为. 这种发光行为不仅可以模拟一个荧光"off-on-off"开关和一个荧光"on-off-on"开关, 而且其组装模式和功能上类似于酶的二聚化过程.     

钾离子调控的1,5-萘基桥联双冠醚的

报道了萘基桥联双苯并15-冠-5的合成, 研究了K^＋调控的双冠醚自组装过程以及伴随的独特荧光行为. 这种发光行为不仅可以模拟一个荧光"off-on-off"开关和一个荧光"on-off-on"开关, 而且其组装模式和功能上类似于酶的二聚化过程.     

2-脲基-4[1氢]-嘧啶酮四氢键萘-蒽超分子组装体系:"通过键"机制的单重态能量传递

设计合成了基于2-脉基-4[1氢]-嘧啶酮AADD四氢键萘-葱超分子组装体系UPNa·UPAn.稳态和时间分辨荧光光谱研究表明UPNa·UPAn四氢键组装体可以发生从茶到葱的高效、快速的单重态能量传递过程.体系内光诱导单重态能量传递的速度和效率远大于通过F(o)rster机制的单重态能量传递速率,表明组装体系UPNa·...     

利用聚合物自组装实现绿色荧光蛋白生色团的荧光增强

根据绿色荧光蛋白的发光原理,采用聚乙二醇与聚甲基丙烯酸甲酯的两亲性两嵌段聚合物通过自组装包覆生色团的方式,模拟了绿色荧光蛋白发光,考察了组装行为对光学性能的影响,并将其用于细胞成像.通过核磁共振、高分辨质谱、傅里叶变换红外光谱、凝胶渗透色谱、紫外-可见吸收光谱及荧光光谱等表征了生色团分子和聚合物的结构及性能.生色团紫外最大吸收在371 nm,荧光最大发射峰在428 nm.聚合物和生色团进行组装后,其紫外吸收消失,而最大荧光发射峰强度大大增强,且发生了约70 nm的红移,这是因为组装使得生色团的自由旋转受到了限制,且生色团共平面性增加.动态光散射(DLS)和透射电镜(TEM)证明了纳米粒子的结构和尺寸.由于尺寸适合且具有较好的荧光性能,纳米粒子成功应用于细胞成像.这种绿色荧光蛋白生色团的简单自组装方式在生物成像领域具有良好应用前景.     

基于自组装的纳米材料双芘的原位构筑、转化和生物效应研究

由于预自组装纳米材料的超结构和性能在复杂的生理状态下会发生变化,我们提出了一种新的"体内自组装"策略,即在体内原位构筑自组装纳米材料来代替预组装纳米材料.为了实现和研究体内自组装,开发了双芘建筑模块,该建筑模块组装成纳米材料时伴随着荧光的增强,可用于"观察"自组装过程及最终的自组装纳米材料.本文总结了双芘建筑模块用于体内自组装的优势,系统地介绍了体内自组装的策略.同时探讨了基于体内自组装和转化的双芘材料的生物效应和诊断治疗应用,并展望了双芘自组装纳米材料的未来发展前景.     

一氧化氮响应性高分子荧光探针的构筑及其细胞内成像应用

一氧化氮(NO)是一种普遍存在的生理信号分子,但利用NO作为触发方法来精细调节仿生聚合物的自组装行为的研究却很少.本工作报道一种独特的具有一氧化氮(NO)反应特性的新型pH响应双亲水性嵌段共聚物(doublehydrophilicblockcopolymer,DHBC),其中NO可以自发地触发聚(寡聚乙二醇甲醚甲基丙烯酸酯)-嵌段-聚(NO响应性基元-共-7-硝基苯并呋咱衍生物)(POEGMA-b-P(APUEMA-co-NBD))双亲水嵌段共聚物,分别在酸性和中性环境中发生自组装和形态转变.在引入荧光团之后,这些转变还可以和NO存在下光致诱导电子转移过程被阻断导致荧光增强相关联,从而提供了观察细胞内NO的机会.     

金属离子对中性红预胶束体系的荧光开关效应

探讨了中性红分别与不同浓度的表面活性剂十二烷基磺酸钠和十二烷基苯磺酸钠在预胶束和胶束浓度范围内的自组装行为,并着重探讨了金属离子Cu~(2+),Zn~(2+),Ca~(2+)对这些体系的荧光开关作用。在预胶束范围内,两种体系的稳定性都不好,金属离子的引入对体系的稳定性和荧光强度有很大影响。     

含氧化还原活性基团的荧光分子开关构建与门

报道了一个基于光致电子转移(PET)机理的双稳态荧光分子开关,其中具有氧化还原活性的二茂铁基团作为荧光团蒽PET过程的氧化还原控制单元,通过双Schiff碱C=N键与蒽相连。研究了不同条件下蒽的荧光发射行为。以不同的化学试剂作为体系的输入信号,以不同的荧光发射强度作为输出信号,利用荧光分子开关的质子化反应和氧化反应实现了一个分子水平的逻辑功能。输入信号及其相应的输出结果在分子水平上符合数字逻辑与门的真值表。     

2-羟基-3-异丙氧基丙基羟乙基纤维素的合成及其自组装行为的研究

通过醚化反应, 将疏水性试剂异丙基缩水甘油醚(IPGE), 接枝到以羟乙基纤维素为亲水性骨架的主链上, 合成了具有温度响应性的2-羟基-3-异丙氧基丙基羟乙基纤维素(HIPEC), 运用核磁共振(¹H NMR、¹³C NMR、2D HSQC NMR)对HIPEC进行结构表征, 其最低临界溶解温度(LCST)可通过改变疏水侧链的摩尔取代度(MS)和盐浓度来调节. 通过荧光光谱仪、动态光散射(DLS)、共聚焦荧光显微镜(CLSM)研究了HIPEC在水溶液中自组装行为及Nile Red在HIPEC胶束中的增溶行为和温度控制释放行为, 结果表明, HIPEC在溶液中自组装形成胶束, 并且胶束粒径随着温度的升高而增大; 在温度高于LCST时, Nile Red从HIPEC胶束中缓慢释放, 并且可通过改变温度控制Nile Red的释放过程.     

荧光标记法研究水含量对两亲性超支化共聚物组装体形貌的影响

合成了丹磺酰基(DNS)标记的两亲性超支化共聚物,DNS-PEHO-star-PEO.用荧光标记法研究了DNS-PEHO-star-PEO在四氢呋喃(THF)/H2O混合溶剂中不同水含量下的自组装行为.结果表明,水含量对DNS-PEHO-star-PEO形成的组装体形貌影响显著.含水含量小于20 vol%时,DNS-PEHO-star-PEO组装成纳米尺寸的球形胶束;随着水含量增加到?75 vol%时,DNS-PEHO-star-PEO组装成"多胶束聚集体";纯水中(水量100 vol%),DNS-PEHO-star-PEO形成微米尺寸的聚合物大囊泡.利用不同形貌聚集体中DNS的荧光发射谱不同的特性,我们绘制了不同聚集体中DNS的荧光最大发射峰波长与水含量的关系图,直观地反映了水含量对DNS-PEHO-star-PEO组装体形貌的影响.     

"Alpha"-, "beta"- and "delta"-anhydrodigitoxigenin

The syntheses of 3β-hydroxy-5β-carda-14, 20:22-dienolide (= «β»-anhydro-), 3β-hydroxy-5β-carda-8:14, 20:22-dienolide (= «α»-anhydro-) and «δ»-anhydro-digitoxigenin (= probably 3β-hydroxy-5β, 14β-carda-8, 20:22-dienolide) by the best ways known to date, have been described. «δ»-Anhydro-digitoxigenin represents the thermodynamically most stable isomer. In this isomer the double bond in position 8 is unaffected by hydrogenation with Pt in acetic acid; with perbenzoic acid an epoxide results from which, on hydrogenation, the double bond can be regenerated in its original position. Analogous reactions are known to occur in the 8:14-epoxides.     

化“材”为“筑”

Chemistry is a central, practical and creative discipline. The development of chemistry plays an important role in the progress of science and society, as well as the improvement of the quality of human life. This paper introduces the chemical knowledge of stone, concrete, glass and other inorganic nonmetallic building materials by the anthropomorphically story. Taking nanomaterials as an example, the prospect of building materials development in the future is put forward.     

Making "wheels" and "cubes" from triangles

[Mn(IV)Mn(II)3] triangular units directed by the presence of tripodal alcohols self-assemble in the presence of azide and acetate ligands to form either a [Mn24] "wheel" or a [Mn32] "cube".     

"Turn-on" fluorescent sensing with "reactive" probes

Chemical probes are valuable tools for the investigation of biochemical processes, diagnosis of disease markers, detection of hazardous compounds, and other purposes. Therefore, the development of chemical probes continues to grow through various approaches with different disciplines and design strategies. Fluorescent probes have received much attention because they are sensitive and easy-to-operate, in general. To realize desired selectivity toward a given analyte, the recognition site of a fluorescent probe is designed in such a way to maximize the binding interactions, usually through weak molecular forces such as hydrogen bonding, toward the analyte over other competing ones. In addition to such a supramolecular approach, the development of fluorescent probes that sense analytes through chemical reactions has witnessed its usefulness for achieving high selectivity, in many cases, superior to that obtainable by the supramolecular approach. Creative incorporations of the reactive groups to latent fluorophores have provided novel chemical probes for various analytes. In this feature article, we overview the recent progress in the development of turn-on fluorescent probes that are operating through chemical reactions triggered by target analytes. Various chemical reactions have been implemented in the development of many reactive probes with very high selectivity and sensitivity toward target analytes. A major emphasis has been focused on the type of chemical reactions utilized, with the hope that further explorations can be made with new chemical reactions to develop reactive probes useful for various applications.     

"Clickable" polymersomes

Polymersomes, composed of amphiphilic polystyrene-block-poly(acrylic acid) (PS-b-PAA), with the periphery being covered with azide groups, were used for further functionalization using "click" chemistry.