苯丙氨酸衍生物手性凝胶的制备及其应用

手性超分子凝胶材料在传感器、人工触角、药物缓释、细胞培养等领域表现出潜在的应用前景。本文合成了一种新型的含偶氮苯官能团的D/L苯丙氨酸手性凝胶因子ALP和ADP,具有对称且完全相反的手性信号。该凝胶因子在多种有机溶剂和水混合溶剂中均可形成稳定的淡黄色凝胶,其中在DMSO和水混合溶剂中表现出最优的成凝胶性能,临界成胶浓度可达2.0mg/mL,表明该手性凝胶因子具有良好的成凝胶性能。手性凝胶可对热、光、pH等外界环境刺激产生响应,并伴有宏观上的凝胶-溶胶相互转变。手性凝胶因子自组装形成了不同螺旋纳米纤维结构,并发现L型手性纳米纤维相对于D型手性纳米纤维对细胞具有更好的粘附与增殖效果。     

不同功能基团的有机盐作为低相对分子质量凝胶因子对原油的成胶性能

低相对分子质量凝胶作为治理原油泄漏的材料具有一些优异的性能,但其在水油相中的成胶规律仍不明确,本文以有机酸及有机胺为原料设计合成了一系列有机盐。 通过核磁共振波谱仪(NMR)、傅里叶红外光谱仪(FTIR)、扫描电子显微镜(SEM)和倒挂实验等技术手段表征了有机盐的结构和成胶性能。 结果表明,有机盐A3C3(A3:肉桂酸;C3:月桂胺)在室温下能使原油形成稳定凝胶,成胶溶度为质量分数6%,该分子在溶剂中自组装形成树枝状三维网状结构。 凝胶的形成需要分子间π-π堆积作用、氢键、静电作用和范德华力等多种作用力协同作用,分子间的π-π堆积作用有利于凝胶的形成,含有多个苯环的凝胶因子更易在芳香族溶剂中形成凝胶。 这些成胶规律对处理原油泄漏的低相对分子质量凝胶因子的设计合成具有实际的指导意义。     

刺激响应型树状分子凝胶的研究进展※

近年来, 刺激响应型超分子凝胶作为一类智能软物质材料, 在离子识别材料、自修复材料、生物材料和药物缓释等领域展现出了非常好的应用前景, 受到人们广泛关注. 树状分子是一类具有高度支化结构的大分子, 其形成的凝胶兼具有机小分子凝胶和聚合物凝胶的双重优点, 树状分子丰富的多层次支化几何结构有利于修饰不同功能基团, 从而确保各功能基团彼此独立作用而不相互干扰, 这种特性使其在构筑多功能化凝胶材料, 尤其是多重环境刺激响应型凝胶材料方面具有独特优势. 基于此, 本综述从树状分子凝胶因子设计、成凝胶机理、响应性能和响应机理等方面详细归纳了刺激响应型树状分子凝胶的研究进展. 按照刺激源不同, 主要从光响应型、氧化还原响应型、离子响应型、触变响应型和多重响应型五个方面对刺激响应树状分子凝胶进行了系统归纳总结. 最后, 基于目前刺激响应树状分子凝胶存在的一些问题对该领域未来发展进行了展望.     

基于苯硼酸的树枝状凝胶及其刺激响应

具有葡萄糖识别性质的超分子凝胶体系在医学诊断领域具有广泛的应用前景。本文通过简单的缩合反应成功构筑了基于苯硼酸和聚芳醚单元的树枝状凝胶因子,其结构利用核磁共振谱和质谱进行了表征。研究了该凝胶因子的凝胶化能力,利用UV-Vis、SEM和SAXS研究了其自组装机理和形貌。构筑的凝胶对热、酸碱和D-葡萄糖表现出多重刺激响应行为。本研究为构筑具有多功能性的软材料提供了一定的理论研究基础。     

偶氮苯功能化的光响应共价有机框架材料

通过后修饰的方法,在共价有机框架(COFs)材料JUC-500的孔道中引入光敏性的偶氮苯小分子,合成了具有光热刺激响应的共价有机框架材料JUC-501.在紫外线和加热作用下,孔道中的偶氮苯会发生可逆的顺-反异构变化,对染料污染物甲基橙(MO)表现出优异的可逆吸附与释放性能.     

刺激响应型超分子凝胶

随着超分子化学的日益发展,刺激响应型超分子凝胶作为一种超分子材料受到人们广泛关注。超分子凝胶是由非共价键作用力自组装而成,基于这一特性,当超分子凝胶受到外界刺激（如温度、光、pH、化学物质、机械力等）时,该凝胶能够产生响应,如溶胶-凝胶转化、颜色变化或荧光变化等。刺激响应型超分子凝胶在离子识别材料、自修复材料、生物材料等领域展现出了非常好的应用前景。本文综述了近五年来刺激响应型超分子凝胶的研究进展,并根据刺激种类的不同,将超分子凝胶分为以下几类：热敏感型超分子凝胶、化学物质和pH响应型超分子凝胶、光敏感型超分子凝胶、氧化还原响应型超分子凝胶、机械力刺激响应型超分子凝胶和多重刺激响应型超分子凝胶。本文根据上述分类对超分子凝胶进行了介绍,同时对该研究领域作了展望。     

基于金属配位和主客体相互作用分级自组装构筑超分子凝胶

将金属配位和主客体相互作用引入到同1个超分子体系中,设计合成了2个超分子单体1和2.通过这2个超分子单体分级自组装形成的交联网状超分子聚合物构建了一种多重刺激响应性和良好自修复性能的超分子凝胶.同时,进一步将具有聚集诱导发光性能的四苯乙烯引入到这种超分子体系中,以赋予超分子体系新颖的发光性能.单体分子1是由中间为双苯并24-冠-8的冠醚连接2个四苯基乙烯荧光生色团,两端为2个三联吡啶分子构成的1个主体分子.单体分子1两端的三联吡啶基团可以与过渡金属Zn(OTf)2进行金属配位形成线型超分子聚合物3;而中间的冠醚基团与双二级铵盐客体分子2通过主客体相互作用进一步形成交联超分子聚合物4.当该交联超分子聚合物的浓度达到30 mmol/L时,可形成荧光超分子聚合物凝胶.通过核磁共振(1H-NMR和DOSY)与黏度等测试方法,证明了线形和交联超分子聚合物的形成,并进一步通过流变的测试证明了超分子聚合物凝胶的形成及其良好的自修复性能.除此之外,由于引入的主客体相互作用以及金属配位固有的刺激响应性,该荧光超分子聚合物凝胶表现出对温度、p H值、K+离子和竞争配体的刺激响应性能.     

基于AIE效应的多重刺激响应性聚合物纳米微球的制备及其细胞示踪应用

基于AIE分子和智能响应性聚合物构筑的纳米材料,具有优良的AIE发光性能、环境刺激响应性和生物相容性,已在生命科学领域展现出诱人的应用前景. 本研究通过ATRP活性聚合方法, 以合成的TPE-BIB为引发剂, 引发具有多刺激响应特性的N-[2-(二乙氨基)-乙基]丙烯酰胺单体聚合, 成功制备具有温度/pH/CO₂三重响应性的两亲性聚合物: TPE-g-PDEAEAM, 并自组装形成约200 nm的纳米微球. 研究表明: 这种聚合物纳米粒子具有优良的水溶性、单分散性、稳定性及优异的AIE发光特性. 其相转变温度为60 ℃, 溶液荧光对环境温度、pH及CO₂均表现出快速敏感响应性能. 同时, 该纳米粒子表现出低细胞毒性, 能够有效示踪HeLa细胞增殖至11代以上, 有望作为一种活细胞荧光示踪探针材料.     

N-月桂酰-L-谷氨酸及其衍生物的凝胶性质研究

N-月桂酰-L-谷氨酸及其衍生物作为小分子凝胶因子可在有机溶剂中形成有机凝胶.通过观察成胶情况,测定最小成胶浓度,分析红外光谱,可以判断N-月桂酰-L-谷氨酸二丁酰胺的成胶能力最强,N-月桂酰-L-谷氨酸次之,N-月桂酰-L-谷氨酸二乙酯最弱.有机凝胶的稳定性与凝胶因子分子间的氢键、凝胶因子和有机溶剂间的氢键密切相关,N-月桂酰-L-谷氨酸二丁酰胺为凝胶因子的凝胶较稳定,乙醇-水为溶剂的凝胶也较稳定,因此分子间的氢键在凝胶的形成中起着关键的作用.     

气态酸和有机胺响应的超分子凝胶

超分子凝胶是由有机分子在非共价键作用力驱动下自组装形成的一种具有液态和固态双重性质的软物质。超分子凝胶能对多种外界刺激做出响应,广泛应用于催化和传感等领域。与传统的小分子探针相比,超分子凝胶传感器显示出了多种检测模式和多信号输出的优点,如超分子凝胶材料的内部三维网络结构和较大的接触面积有利于分析物的快速渗透,并且其凝胶状态的变化可以作为检测过程中的输出信号。此外,干凝胶薄膜材料还具有三维网络结构,在检测气体分析物方面表现出优异的检测性能。本文重点介绍了超分子凝胶在气态酸和有机胺检测中的应用以及相关超分子凝胶的设计和检测机理,为构建用于气态酸和有机胺检测的新型超分子凝胶提供了参考。最后总结了超分子凝胶在气态酸和有机胺检测中存在的问题及应用前景。     

Quinoline-cored Poly(Aryl Ether) Dendritic Organogels with Multiple Stimuli-Responsive and Adsorptive Properties

Functional supramolecular gel materials have potential applications in sensors, optical switches, artificial antennae, drug delivery and so on. In this paper, quinoline-cored poly(aryl ether) dendritic organogelators were designed, synthesized and fully characterized. The gelation behaviour of the dendritic organogelator was tested in organic solvents, mixed solvents and ionic liquids. The dendron Q-G1 was found to be an efficient and versatile organogelator toward various apolar and polar organic solvents with the critical gelation concentrations (CGCs) approaching 1.2×10^?2 mol/L, indicating one dendritic organogelator could immobilize 1.2×10³ solvent molecules in the organogel network. Interestingly, these dendrons exhibited excellent gel formation in ionic liquids. Notably, these dendritic organogels were found to display multiple stimuli-responsive properties toward external stimuli including heat, ultrasound and shear stress, with a reversible sol-gel phase transition. In addition, the dendritic organogel could effectively adsorb heavy metals and organic dyes. The removal rate of Pb²⁺ was up to 20% and the adsorption rate for Rhodamine B was as high as 89%.     

Functional organogel based on a salicylideneaniline derivative with enhanced fluorescence emission and photochromism

A new organogelator based on a salicylideneaniline derivative with cholesterol moieties was synthesized, and it was proposed that it could gelate various organic solvents, such as 1-butanol, 1-octanol, butyl acetate, tetrachloromethane, benzene, toluene through combination with a gelation test. From the results of analysis by UV/Vis absorption, circular dichroism (CD), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies and semiempirical (AM1) calculations, we believed that the gelator molecules could self-assemble into left-handed helical nanofibers through unimolecular layer packing, which further twisted into the thicker fibers and constructed 3D networks in the gel phase. Interestingly, the organogel exhibited strong fluorescence enhancement relative to a solution of the same concentration because of the formation of J aggregations. Meanwhile, photochromism of the organogel could take place under UV-light irradiation. Both strong fluorescence emission and photochromism properties were concurrent in one system based on a salicylideneaniline derivative. It was suggested that the self-assembly of the functional organogelator could lead to unique photophysical properties.     

Synthesis of reversible fluorescent organogel containing 2-(2′-hydroxyphenyl)benzoxazole: fluorescence enhancement upon gelation and detecting property for nerve gas simulant

A new low molecular mass organogelator 1 containing 2-(2′-hydroxyphenyl)benzoxazole (HPB) group with long alkyl chain was synthesized by the reaction with 5-amino-2-(2′-hydroxy-4′-methylphenyl)benzoxazole and dodecyl isocyanate in THF at room temperature. The reversible gelation ability of 1 was investigated using a heating-cooling method in various organic solvents. The stable organogel was formed from carbon tetrachloride or from cyclohexane at the concentration as low as 0.9%. The self-assembled supramolecular gel structure formed by non-covalent bonding was confirmed with field emission-scanning electron microscope (FE-SEM) exhibiting fibril- or ribbon-shaped structure depending on the solvent used. Regarding the aggregation-induced emission enhancement (AIEE) phenomenon, the optical properties were investigated in its solution and gelled state. The detecting properties of resulting organogel toward nerve gas simulant were monitored by UV-vis and fluorescence spectroscopy. Both color change from colorless to greenish yellow and disruption of gel structure resulting from alteration in intermolecular forces were observed upon the exposure to nerve gas simulant.     

Novel CuS nanofibers using organogel as a template: controlled by binding sites

A new cholesterol organogelator 1 was synthesized, which was confirmed as an effective gelator for various organic solvents and could self-assemble into network fibers in some organic solvents. Moreover, gelator 1 could act as templates for the synthesis of various CuS nanofibers with different helical pitches. For example, when H(2)S was used as the sulfur source, straight and bending helical CuS nanofibers with a pitch of 100-200 nm could be fabricated in butyl acetate and benzene-butanol gel systems, respectively, while bending CuS nanofibers with a similar helical pitch (ca. 50 nm) could be obtained when thioacetamide was used as the sulfur source in both gel systems. It was first found that the morphologies of inorganic nanofibers could be controlled by the binding sites between the inorganic precursor and the organogel.     

溶剂和分子结构对席夫碱分子在有机凝胶中的荧光增强和超分子手性的影响

研究了在有机胶凝剂中掺杂的席夫碱化合物的结构和性质. 实验发现, 虽然席夫碱分子单独不能在有机溶剂中形成凝胶, 当其与一种胶凝剂N,N’-双十八烷基-L-Boc-谷氨酸混合时, 它们在二甲基亚砜或甲苯中形成透明的有机凝胶. 与相应的溶液相比, 观察到在有机凝胶中的荧光增强现象, 并且这一增强与席夫碱的结构有密切关系. 在二甲基亚砜的有机凝胶中, 观察到带有长烷基链的席夫碱具有诱导手性. 表明通过凝胶的形成, 胶凝剂的手性能传递到带有长链的席夫碱上.     

Effect of Solvent and Molecular Structure on the Enhanced Fluorescence and Supramolecular Chirality of Schiff Bases in Organogels

The structures and properties of some Schiff base compounds doped in organogels were investigated. It was found that although individual Schiff bases could not form organogels with organic solvents, they can gel by mixing with an organogelator, N,N′-bisoctadecyl-L-Boc-glutamic-diamide, which formed transparent organogels in dimethyl sulfoxide (DMSO) or toluene (Tol). The enhancement of doping Schiff bases fluorescence in the organogel was observed in comparison with that of the corresponding solution. Furthermore, in the DMSO organogel, the induced chirality was obtained from the doping Schiff base with long alkyl chain. In contrast, the Schiff bases without long alkyl chain could not form supramolecular chiral assemblies in organogel. It was suggested that through gel formation the chirality of the gelator could be transferred to the Schiff base through hydrophobic interaction among the long alkyl chains.     

Creation of chiral thixotropic gels through a crown-ammonium interaction and their application to a memory-erasing recycle system

A unique class of oligothiophene-based organogelator bearing two crown ethers at both ends was synthesized. This compound could gelatinize several organic solvents, forming one-dimensional fibrous aggregates. From the observation of circular dichroism, it was confirmed that the helical handedness of the fibrous assembly is controllable by the chirality of 1,2-bisammonium guests, thus suggesting that one guest molecule bridges two gelator molecules through the crown-ammonium interaction. Interestingly, we have found that such chirality is created by thermal gelation, whereas it disappears by thixotropic gelation. The new finding implies that the present organogel system is applicable as a reversible switching memory device, featuring memory creation by a heat mode and memory erasing by a mechanical mode.     

Creation of Chiral Thixotropic Gels through a Crown–Ammonium Interaction and their Application to a Memory‐Erasing Recycle System

A unique class of oligothiophene‐based organogelator bearing two crown ethers at both ends was synthesized. This compound could gelatinize several organic solvents, forming one‐dimensional fibrous aggregates. From the observation of circular dichroism, it was confirmed that the helical handedness of the fibrous assembly is controllable by the chirality of 1,2bisammonium guests, thus suggesting that one guest molecule bridges two gelator molecules through the crown–ammonium interaction. Interestingly, we have found that such chirality is created by thermal gelation, whereas it disappears by thixotropic gelation. The new finding implies that the present organogel system is applicable as a reversible switching memory device, featuring memory creation by a heat mode and memory erasing by a mechanical mode.     

Helical ribbon aggregate composed of a crown-appended cholesterol derivative which acts as an amphiphilic gelator of organic solvents and as a template for chiral silica transcription

New crown-appended cholesterol-based organogelator 1, which has two cholesterol skeletons as a chiral aggregate-forming site, two amino groups as an acidic proton-binding site, and one crown moiety as a cation-binding site, was synthesized, and the gelation ability was evaluated in organic solvents. It can gelate acetic acid, acetonitrile, acetone, ethanol, 1-butanol, 1-hexanol, DMSO, and DMF under 1.0 wt %, indicating that 1 acts as a versatile gelator of various organic solvents. To characterize the aggregation mode in the organogel system, we observed a CD spectrum of the acetic acid gel 1. In the CD spectrum, the lambda(theta)=0 value appears at 353 nm, which is the same as the absorption maximum lambda(max) = 353 nm. The positive sign for the first Cotton effect indicates that the dipole moments of azobenzene chromophores tend to orient in a clockwise direction. Very surprisingly, the TEM images of the 1 + acetic acid gel resulted in the helical ribbon and the tubular structures. Sol-gel polymerization of tetraethoxysilane was carried out using 1 in the gel phase. The silica obtained from the 1 + acetic acid gel showed the helical ribbon with 1700-1800-nm pitches and the tubular structure of the silica with approximately 560-nm outer diameter. As far as can be recognized, all the helicity possesses a right-handed helical motif. Since the exciton-coupling band of the organogel also shows R (right-handed) helicity, we consider that a microscopic helicity is reflected by a macroscopic helicity.