D-π-A分子H-聚集体的电子光谱

合成了具有强化给体和强电子受体的D-π-A分子5-(4-N,N-二甲氨基苯乙烯基)-(1H,3H)-2,4,6-嘧啶三酮(AB1)和5-(4-N,N-双十八烷基氨基苯乙烯基)-(1H,3H)-2,4,6-嘧啶三酮(AB18),并对其电子光谱进行了研究,AB18在环 聚集体的吸收光谱及AB1和AP18的表面光电压谱在450nm附近出现H-聚集体的谱带,比其在氯仿溶液中单体的ICT带蓝移了30nm左右,AB1和AB18固体及其高浓度的氯仿溶液分别在620nm和610nm附近出现来源于H-聚集体的激基缔合物的荧光,620nm带比单体红移3000cm^01 左右,还探讨具有强电子给体和受体的D-π-A分子间π-π相互作用.     

非离子型水溶性卟啉功能化单壁碳纳米管的研究

合成了两种非离子型水溶性卟啉分子,并利用它们对单壁碳纳米管(SWNTs)进行了非共价表面修饰。功能化后SWNTs能够在水中均匀分散。紫外-可见光谱、荧光光谱、透射电镜的测试结果均证明非离子型水溶性卟啉分子与SWNTs之间存在强烈的相互作用。其中,含有柔性烷基取代链的卟啉分子因与SWNTs之间存在π-π和疏水双重相互作用,所形成的复合物在水中表现出更好的分散稳定性。这种既具有水溶性又具有生物相容性和良好稳定性的功能化SWNTs,在生物医药领域具有潜在的应用前景。     

蒽与苯甲酸及其衍生物之间的作用机理研究

用紫外差光谱、红外光谱法和荧光猝灭法研究了典型多环芳烃蒽与苯甲酸及其羟基取代衍生物邻羟基苯甲酸和对羟基苯甲酸之间的作用机理。实验结果表明,在此芳香羧酸与蒽之间存在定向的、特异性的作用,其作用方式受到反应物结构和环境酸度的影响。对苯甲酸和邻羟基苯甲酸而言,当pH<pKa时,二者之间以蒽离域大π电子与羧基质子之间的π-H氢键作用为主,pH>pKa时,π-π电子给体受体作用逐渐成为主要结合方式。邻位羟基的存在使得苯甲酸与蒽的作用强度明显降低。对羟基苯甲酸特殊的D-π-A型分子结构使得它在溶液中形成平面多分子聚集体,这种多分子聚集体的生成使得对羟基苯甲酸与蒽的结合方式不随酸度变化,在pH2.0~10.0的范围内均以π-π电子给体受体作用相结合,且结合强度大于苯甲酸和邻羟基苯甲酸。     

5,10,15,20-四(4-(4-吡啶)酮基)苯基卟啉的合成、表征及晶体结构

利用丙酸法合成了一种新的化合物5,10,15,20-四(4-(4-吡啶)酮基)苯基卟啉,并进行了IR,UV-Vis,MS及EA表征,探讨了试剂4-羟基吡啶的异构现象及合成方法。采用溶液结晶法得到了该卟啉分子的晶体,对其进行了X-射线单晶衍射及粉末衍射测定。结果表明:该晶体属于正交晶系,空间群为Fddd。相邻的卟啉分子通过吡啶环之间的π…π作用与其他卟啉分子相连形成二维层状结构。层与层之间进一步通过吡啶环与卟啉环之间的π…π作用而形成三维超分子结构。该化合物可以作为构建金属卟啉框架新材料(MPF)的良好配体。     

N-乙氧羰基-N'-取代芳基硫脲晶体中的弱相互作用及超分子结构研究

合成了3种N-乙氧羰基-N'-取代芳基硫脲并确定了其晶体结构,晶体结构表明,在这些化合物中存在分子内及分子间的氢键,分子间的氢键将化合物1和2组装成了一维链状的超分子结构,由于空间因素,化合物3没有形成类似于1,2中的氢键组装成的链状超分子结构,而是形成了氢键链接的二聚体.同时在化合物1,3中还存在分子间的芳环间的π-π相互作用.在化合物1的晶体中,这种π-π相互作用使相邻的超分子链之间相互关联.化合物3的晶体中,相邻的二聚体间又通过π-π相互作用连接成了无限延伸的一维链状结构.     

单核锌双卟啉配合物构象平衡的理论研究及光谱分析

合成了一系列以不同长度柔韧链相连的p/p型单核锌双卟啉配合物。选用Tripos力场,利用分子动力学模拟退火和分子力学构象搜索相结合的方法对该系列双卟啉进行了能量优化和构象分析。理论计算结果表明:该类双卟啉稳定存在的最低能量构象为叠合式,最高能量构象为伸展式,并存在一系列的中间能量构象;双卟啉分子内π-π作用和能量转移与双卟啉存在的两种主要构象密切相关;分析了分子内π-π作用的本质。运用不同光谱测试手段验证了理论计算结果: 利用可见和相应二阶导数吸收光谱研究了双卟啉主要存在的叠合式和伸展式构象,通过红外光谱观察了对双卟啉构象和卟啉环间π-π作用较为敏感的吸收谱带;利用荧光光谱计算了双卟啉的分子内能量转移效率。     

具有不同取代链长的卟啉衍生物LB膜的结构研究

本文研究了三种羧酸取代的四苯基卟啉衍生物在空气/Cd^2^+水溶液界面上所形成的单层膜及LB膜。这三种卟啉衍生物中, 一种没有脂链, 另外两种具有不同长度的脂链。由π-A等温线得到的平均表观分子面积相差很大。紫外-可见光谱表明, LB膜中卟啉的Soret吸收带相对于溶液的吸收均红移, 但红移程度不同。LB膜的偏振紫外-可见光谱表明, LB膜中三种卟啉衍生物的卟啉环具有基本一致的取向。运用亚相降低法得到了三种卟啉衍生物单层LB膜, 其紫外-可见光谱与用垂直提拉法得到的LB膜的紫外-可见光谱具有一致的特征。这些结果表明: 卟啉衍生物有无取代链及取代链长的不同对平均表观分子面积的大小和膜中环间的距离有影响, 但对环的取向没有影响。环的取向由环本身及环上的亲水取代基来确定。气/液界面上三种卟啉衍生物的单层膜中环也具有一致的取向, 且与LB膜中环的取向相差不大。提拉不会对膜中环的取向及膜的结构造成大的改变。     

环己烷并卟啉的合成及光谱和电化学性质研究

合成了三种在中位上具有不同取代苯基的环己烷并卟啉:5,10,15,20-四(4-甲苯基)环己烷并卟啉,5,10,15,20-四苯基环己烷并卟啉和5,10,15,20-四(4-氯苯基)环己烷并卟啉。利用核磁共振及质谱对它们进行了结构表征,研究了它们在二氯甲烷和吡啶溶剂中的紫外-可见光谱和电化学性质,探讨了卟啉大环周边的取代基和溶剂对化合物的光谱和氧化还原电位的影响,发现β-位上的环己烷取代基对化合物的光谱和电化学性质具有显著的影响。     

亚苄基山梨醇衍生物在有机溶剂中的自组装及凝胶化研究

从分子结构的差异、亲溶剂作用、分子几何构型、相转变热焓以及溶剂极性等方面研究了三种亚苄基山梨醇衍生物凝胶剂在有机溶剂中的自组装和凝胶化机理. 三种衍生物凝胶剂在结构上的差别仅在于亚苄基上甲基取代基数量不同. 结果表明: 由于亲溶剂作用的增加和分子几何构型的优化, 含甲基多的凝胶剂在有机溶剂中的自组装能力强, 表现在具有低的最低凝胶化浓度和高的相转变温度. 而溶剂极性的增强, 使三种衍生物凝胶剂形成的凝胶相转变温度降低. 偏光显微镜照片表明该凝胶剂在正辛醇凝胶中的聚集体晶型不同. 场发射扫描电镜照片表明三种衍生物凝胶剂自组装形成相互缠绕的纤维束网络结构. 紫外吸收光谱表明, 对比其溶液态, 三种衍生物聚集体苯环的K带发生红移, 表明π-π堆积作用是亚苄基山梨醇衍生物凝胶剂自组装的驱动力之一; 红移的幅度随苯环上甲基数量的增加而增加, 这与三种衍生物形成的分子凝胶的热稳定性相吻合.     

以苝二酰亚胺为构筑块的超分子聚集体的研究进展

苝二酰亚胺(PDI)超分子聚集体以其独特的光物理和光化学性质而受到广泛的关注.本文首先简单介绍了苝二酰亚胺的性质及合成,然后分别介绍了在配位键、π-π堆积、氢键以及正负离子的静电引力作用下组装超分子聚集体的研究现状.最后对苝二酰亚胺超分子聚集体的发展前景作了展望.     

Synthesis and cell phototoxicity of a triply bridged fused diporphyrin appended with six thioglucose units

A triply bridged fused diporphyrin appended with six thioglucose units is reported. This new, chemically, and photochemically stable amphiphilic compound is taken up by breast cancer cells and causes cell death upon light exposure. Photophysical studies reveal absorption bands in the near IR region, and photosensitized formation of singlet oxygen in high quantum yields.     

Biodegradable and Biocompatible Silatrane Polymers

In this study, new biodegradable and biocompatible amphiphilic polymers were obtained by modifying the peripheral hydroxyl groups of branched polyethers and polyesters with organosilicon substituents. The structures of the synthesized polymers were confirmed by NMR and GPC. Organosilicon moieties of the polymers were formed by silatranes and trimethylsilyl blocks and displayed hydrophilic and hydrophobic properties, respectively. The effect of the ratio of hydrophilic to hydrophobic organosilicon structures on the surface activity and biological activity of macromolecules was studied, together with the effect on these activities of the macromolecules’ molecular weight and chemical structure. In particular, the critical micelle concentrations were determined, the effect of the structure of the polymers on their wetting with aqueous solutions on glass and parafilm was described, and the aggregation stability of emulsions was studied. Finally, the effect of the polymer structures on their antifungal activity and seed germination stimulation was examined.     

Amphiphilic micro- and nanogels: Combining properties from internal hydrogel networks,solid particles,and micellar aggregates

Polymeric micro- and nanogels are defined by their water-swollen hydrophilic networks that can often impart outstanding biocompatibility and high-colloidal stability. Unfortunately, this highly hydrophilic nature limits their potential in areas where hydrophobic or amphiphilic interactions are required, for example, the delivery of hydrophobic cargoes or tailored interactions with amphipathic (bio-)surfaces. To overcome this limitation, amphiphilic micro−/nanogels are emerging as new colloidal materials that combine properties from hydrogel networks with hydrophobic segments, known from solid hydrophobic polymer particles or micellar cores. The ability to accurately adjust the balance of hydrophobic and hydrophilic components in such amphiphilic colloidal systems enables new tailored properties. This opens up new applications ranging from the controlled and sustained delivery of hydrophobic drugs, over carriers for catalytic moieties, to their assembly at hydrophilic/hydrophobic interfaces, for example, as advanced stabilizers in Pickering emulsions. While promising, the synthetic realization of such amphiphilic materials remains challenging since hydrophobic and hydrophilic moieties need to be combined in a single colloidal system. As a result, adjusting the micro−/nanogel amphiphilicity often changes the colloidal features too. To overcome these limitations, various strategies have been reported. The aim of this review is to give a brief overview of important synthetic tools, considering both advantages and disadvantages, thus critically evaluating their potential in different research fields.     

pH敏感性两亲聚合物网络PAA—l—PTHF的研究

以具有良好柔性和生物相容性的聚四氢呋喃（ＰＴＨＦ）为疏水链段,具有ｐＨ敏感性的聚丙烯酸（ＰＡＡ）为亲水链段,通过ＰＴＨＦ双端基大分子单体与丙烯酸自由基共聚,首次合成了聚丙烯酸－ｌ－聚四氢呋喃（ＰＡＡ－ｌ－ＰＴＨＦ）两亲聚合物网络,并对网络的结构、组成以及交联点密度进行了表征。两亲聚合物网络溶胀行为研究表明,ＰＡＡ－ｌ－ＰＴＨＦ既能在水中溶胀又能在有机溶剂中溶胀,在水中的溶胀度随网络亲水链段ＰＡＡ含     

Synthesis of amphiphilic polysiloxanes and their properties for formation of nano-aggregates

In this study, we prepared amphiphilic polysiloxanes by introduction of hydrophobic and hydrophilic parts into a water-soluble poly(3-aminopropyl)siloxane. Fatty acid (lauroyl, myristoyl, palmitoyl, and stearoyl) chlorides and gluconolactone were employed as the reactants for the hydrophobic and hydrophilic parts, respectively. The reaction of the poly(3-aminopropyl)siloxane with fatty acid chlorides was performed in water/DMF, followed by the reaction with gluconolactone in DMSO, giving the corresponding amphiphilic polysiloxanes. The results of the NMR spectra, SEM observations, and DLS measurements indicated the formation of nano-aggregates from the amphiphilic polysiloxanes in water. These analytical data also suggested that the structures and functionalities of the hydrophobic parts affected the formation properties of the nano-aggregates.     

Self-assembly and morphology control of new L-glutamic acid-based amphiphilic random copolymers: giant vesicles, vesicles, spheres, and honeycomb film

New amphiphilic random copolymers containing hydrophobic dodecyl (C12) chain and hydrophilic L-glutamic acid were synthesized, and their self-assembly in solution as well as on the solid surfaces was investigated. The self-assembly behavior of these polymers are largely dependent on their hydrophilic and hydrophobic balances. The copolymer with a more hydrophobic alkyl chain (～90%) self-assembled into giant vesicles with a diameter of several micrometers in a mixed solvent of ethanol and water. When the hydrophobic ratio decreased to ca. 76%, the polymer self-assembled into conventional vesicles with several hundred nanometers. The giant vesicles could be fused in certain conditions, while the conventional vesicles were stable. When the content of the hydrophilic part was further increased, no organized structures were formed. On the other hand, when the copolymer solutions were directly cast on solid substrates such as silicon plates, films with organized nanostructures could also be obtained, the morphology of which depended on solvent selection. When ethanol or methanol was used, spheres were obtained. When dichloromethane was used as the solvent, honeycomb-like morphologies were obtained. These results showed that through appropriate molecular design, random copolymer could self-assemble into various organized structures, which could be regulated through the hydrophobic/hydrophilic balance and the solvents.     

Controllable Self‐Assembly of Amphiphilic Zwitterionic PBI Towards Tunable Surface Wettability of the Nanostructures

Amphiphilic molecules have received wide attention as they possess both hydrophobic and hydrophilic properties, and can form diverse nanostructures in selective solvents. Herein, we report an asymmetric amphiphilic zwitterionic perylene bisimide ( AZP ) with an octyl chain and a zwitterionic group on the opposite imide positions of perylene tetracarboxylic dianhydride. The controllable nanostructures of AZP with tunable hydrophilic/hydrophobic surface have been investigated through solvent‐dependent amphiphilic self‐assembly as confirmed by SEM, TEM, and contact angle measurements. The planar perylene core of AZP contributes to strong π–π stacking, while the amphiphilic balance of asymmetric AZP adjusts the self‐assembly property. Additionally, due to intermolecular π–π stacking and solvent–solute interactions, AZP could self‐assemble into hydrophilic microtubes in a polar solvent (acetone) and hydrophobic nanofibers in an apolar solvent (hexane). This facile method provides a new pathway for controlling the surface properties based on an asymmetric amphiphilic zwitterionic perylene bisimide.     

Solvent-tunable binding of hydrophilic and hydrophobic guests by amphiphilic molecular baskets

[reaction: see text] Responsive amphiphilic molecular baskets were obtained by attaching four facially amphiphilic cholate groups to a tetraaminocalixarene scaffold. Their binding properties can be switched by solvent changes. In nonpolar solvents, the molecules utilize the hydrophilic faces of the cholates to bind hydrophilic molecules such as glucose derivatives. In polar solvents, the molecules employ the hydrophobic faces of the cholates to bind hydrophobic guests. A water-soluble basket can bind polycyclic aromatic hydrocarbons including anthracene, pyrene, and perylene. The binding free energy (-deltaG) ranges from 5 to 8 kcal/mol and is directly proportional to the surface area of the aromatic hosts. Binding of both hydrophilic and hydrophobic guests is driven by solvophobic interactions.     

Synthesis and characterization of poly(vinyl amine)‐based amphiphilic comb‐like dextran glycopolymers by a two‐step method

Poly(vinyl amine) (PVAm)‐based amphiphilic glycopolymers were synthesized by a two‐step method, that is dextran molecules (Dex, M_w = 1500) were attached to the PVAm backbone by reacting amine groups with dextran lactone, and then, hexanoyl groups (Hex) were attached by reacting the PVAm free amine groups with N‐(hexanoyloxy)succinimide. By adjustment of the feed ratios of Dex/Hex, amphiphilic comb‐like glycopolymers with various hydrophilic and hydrophobic balances were prepared, and their structures were characterized by ¹H NMR. Surface activity of the amphiphilic glycopolymers at the air/water interface was demonstrated by reduction in water surface tension. Adsorption of the amphiphilic glycopolymers at the solid/water interface was examined on octadecyltrichlorosilane (OTS)‐coated coverslips by water contact angle measurements. The results show that the amphiphilic glycopolymers need about 20 mol % of dextran attachment to make an effective hydrophilic coating. In comparison with the one‐step reaction by addition of dextran lactone and alkyl succinimide simultaneously, the two‐step approach can attach Dex on PVAm as high as possible in the first step, and offers quantitative advantages in controlling the ratio of hydrophilic and hydrophobic chains along the PVAm backbone, resulting in increased water solubility for the final amphiphilic glycopolymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 192–199, 2006     

Facial amphiphiles in molecular recognition: From unusual aggregates to solvophobically driven foldamers

The term “facial amphiphiles” was originally used for molecules with the hydrophilic and hydrophobic groups located on two opposite faces, rather than at two ends as in the more conventional head/tail amphiphiles. Recent research has expanded this concept and created facially amphiphilic molecules with diverse topologies and intriguing properties. The geometry and the distribution of hydrophilic/hydrophobic groups on facial amphiphiles were key parameters influencing their properties. Intermolecular aggregation of facial amphiphiles generated a range of structures including dimers, vesicles, nanoclusters, and nanotubes. Intramolecular aggregation of facially amphiphilic repeat units in a molecule, on the other hand, allowed the molecule to respond to environmental stimuli through controlled conformational changes.