轮烷研究－从超分子组装到分子器件

轮烷是一类由两端带有大的基团的线性分子和有机环化合物组成的互相锁连的分子化合物。主要综述了近年来这类超分子化合物的合成方法进展、在合成中的应用及其作为分子器件方面的研究进展。     

亚硝基-烯(Nitroso-ene)反应的研究进展

烯丙基胺类化合物是有机化学中的重要合成中间体,亚硝基-烯(nitroso-ene)反应是合成这类化合物最为高效的方法之一.在一些天然产物和药物分子的全合成中,亚硝基-烯反应也往往作为关键步骤.这篇综述主要介绍了亚硝基–烯反应的发展、应用以及机理研究方面的进展.     

二芳基乙烯类光致变色材料的合成概述

由于具有多种潜在的应用价值, 光致变色化合物作为高级功能材料的研究在国内外广受关注. 在众多的有机光致变色化合物中, 二芳基乙烯特别是二噻吩乙烯, 由于其具有良好的热稳定性和优良的耐疲劳度而成为这类化合物的杰出代表. 近年来, 有关二芳基乙烯类光致变色化合物的各种合成及性能方面的报道已涉及到信息存储、分子开关、逻辑电路、液晶显示、磁性材料等众多领域. 主要是从有机合成的角度, 对这类材料的合成进行了较为全面的概括, 对各种合成方法分别加以介绍和分析, 对其发展趋势予以探索和展望.     

新型甾体缀合物的设计合成及活性研究

甾体化合物是一类生物体中广泛存在并起重要功能的生物分子。其特殊结构使这类化合物具有亲脂性,膜亲合性以及与低密度脂蛋白的特异性结合等性能。利用这些特性设计合成各种药物分子的甾体缀合物,可增加药物分子的脂溶性,提高跨膜渗透能力,在特定组织中的分布以及甾体缀合物自身具有独特的生物活性,对探索新型生物活性分子具有重要意义。本文介绍了近年来在设计合成新型甾体缀合物领域的研究进展,包括甾体药物缀合物、含磷甾体缀合物、作为离子通道和分子载体的缀合物及甾体二聚缀合物等。     

新型棒状苯基咪唑苯酯类化合物的合成及其液晶性能研究

以Ullmann偶合反应为关键步骤, 合成了带端氧基链的苯基咪唑苯酯系列化合物, 采用偏光显微镜(POM)、差示扫描量热仪(DSC)及X衍射等手段研究了其液晶行为. 研究表明, 通过改变末端烷氧基链的长度及数目, 这类分子可组装形成向列相(N)和层列相(SmA)等液晶相态, 但随着烷氧基链数目的增多, 这类分子的液晶相消失, 初步找出了这类化合物结构与液晶性能间的关系, 通过对相关化合物的单晶X衍射结构及其液晶相的2D-X衍射测试结果的分析得出, 这类化合物通过分子自组装形成的层列相具有双分子层状结构(SmA₂).     

轮烷类化合物的合成方法研究进展

轮烷类互锁分子因其多样的结构和性质,多年来一直是超分子化学领域的一个热点.综述了近年来轮烷类化合物的合成及制备方法,包括用传统的模板法(引入氢键、疏水作用、静电效应、配位和离子诱导等超分子作用)制备轮烷类化合物.除此之外,还介绍了利用“Click”化学、“穿线-收缩”、“穿线-膨胀”、自排序组织和自由基识别等新的合成手段来制备这类化合物.     

1-茚满酮合成方法研究进展

1-茚满酮类化合物是许多药物和天然产物合成中的中间体, 有关这类化合物的合成方法仍然不断得到更新. 按照关环位点对于这些合成方法进行了综述, 着重介绍了2000以来的合成新进展.     

手性钛锆化合物在不对称合成中的应用

本文综述了近年来手性钛锆化合物在不对称合成中的应用, 特别是手性柄型金属钛和锆化合物在不对称合成中的应用。对这类催化剂的特点和前景作了简要介绍。     

具有生理活性的含氧、氮、硫杂原子螺环化合物的研究进展

综述了近年来部分具有生理活性螺环化合物的研究进展, 重点介绍了这类化合物的结构特征、生理活性和部分化合物的合成方法. 展望了该类螺环化合物的应用前景.     

手性双官能硫族化合物催化烯烃的不对称亲电硫化反应

手性含硫化合物在药物化学和不对称合成领域中应用广泛,发展这类化合物的新合成方法是有机合成化学的重要任务.烯烃的不对称亲电硫化反应为手性含硫化合物的合成提供了一条方便的途径,通过这种方式不仅可以在烯烃母体分子上引入一个含硫基团,同时也能够引入另外一个重要的官能团.我们课题组设计、合成了一系列手性双官能硒醚/硫醚催化剂,并...     

Covalent polymer-drug conjugates

In this work, polymer-drugs conjugates used as drug delivery systems (DDS) are revised attending to their chemical conjugation. Namely, the classification of this type of DDS is based on the conjugation sites of the reactive groups (i.e., via end groups or pendant polymer groups). Advantages and limitations of these types of DDS are discussed through representative examples of polymer-drugs and polymer-proteins conjugates recently developed.     

反应性梳状聚乙二醇改性聚酯薄膜表面及其内皮细胞相容性的研究

以高密度梳状PEG(CPEG)作为表面改性材料, 将PEG末端羟基转化为醛基, 将梳状PEG和线形PEG固定在氨基化的PET膜表面, 并利用表面的反应性醛基进一步固定了氨基酸和整合素配体多肽片段RGD多肽. 红外光谱、 接触角和X射线光电子能谱(XPS)测定结果表明, 该法可有效地固定氨基酸和多肽, 获得模拟细胞膜中多糖-蛋白质复合物结构的特异性功能表面. 对两种不同结构的PEG细胞培养实验结果表明, CPEG比线形PEG(LPEG)具有更好的抗非特异粘附性. 此外, CPEG比LPEG具有更多的活性反应基团, 用PEG末端活性的醛基固定整合素配体多肽片段RGD, 可有效地诱导材料表面的内皮细胞化, 改善材料的细胞相容性.     

Effects of directed architecture in epoxy functionalized prepolymers for photocurable thin films

Cationic photopolymerization has become increasingly important in thin‐film applications for advantages including no oxygen inhibition and rapid polymerization rates. Photocurable cationic thin film properties are often modulated by incorporation of oligomeric and prepolymer materials, but little work has directly examined the effect of prepolymer structure and reactive group placement on the thermomechanical properties of the final material. To explore the role of molecular architecture, epoxy functionalized butyl acrylate gradient copolymers were synthesized with reactive groups in end segments or randomly distributed along the prepolymer chain. Polymerized end functionalized formulations exhibit moduli almost double that of random functionalized oligomer formulations. In addition, inclusion of end functionalized prepolymers decreases creep of resulting thin films by a factor of 10. Furthermore, decreasing the concentration of the cross‐linking diluent in end functionalized prepolymer systems results in amorphous networks with significantly lower mechanical strength. Increasing reactive groups at the ends of prepolymers produces stronger materials without affecting tensile elongation at break. These properties indicate that the structured oligomers facilitate the formation of continuous hard domains with high cross‐link density with inclusions of soft, flexible domains of low cross‐link density. This study demonstrates that the prepolymer architecture governs network formation and ultimate properties. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 144–154     

Perspective thermally stable thermoset binders for polymer composite materials

Brief review of the modern state in the field of thermally stable thermoset resins used as binders for engineering polymer composites in presented. Synthesis, processing, properties, and application of such materials are discussed. The list of binders includes polyimide PMR resins, oligoimides with reactive end groups, bismaleimides, and phthalonitrile resins.     

Structure of Styrene and Acrylate Block Copolymers

Abstract

Using UV light as the energy source and polystyrene- (PS-) or polymethyl methacrylate- (PMMA-) macroinitiators with active aromatic or aliphatic thiyl end groups, PS-PMMA and PMMA-PEA (poly-ethyl acrylate) block copolymers were synthesized. The molecular weights of both block copolymers increased with increasing reaction time. The reactivity of macroinitiators depended on the type of thiyl groups and monomer and not on the length of the polymer chain. The most reactive were macroinitiators containing resonance stabilized non-substituted or substituted aromatic end groups. The decomposition of the macroinitiators took place over the formation of the thiyl radical and macroradical. The bond length, the bond dissociation energy, and the bond order of macroradical end groups were calculated. The most reactive monomer was ethyl acrylate; the less reactive was styrene. The structure, the molecular weight, and the T _g of the styrene-acrylate block copolymers were determined. The PMMA/PEA block copolymer had two of block's T _g s, the first at 105°C, the second at ?24°C, and a third at 16°C which probably represents contacting segments.     

Polycarbonate synthesis by the melt phase carbonate-ester interchange reaction of bisphenol-A diacetate with dimethyl carbonate

The molecular weight of polycarbonate formed by the carbonate-ester interchange reaction of bisphenol-A diacetate (BPAC₂) and dimethyl carbonate (DMC) was found to depend on the composition of the oligomer formed in its first stage. At a [DMC] : [BPAC₂] ratio of 2, an oligomer with relatively higher acetate end group concentration was formed. This upon further polycondensation yielded a polycarbonate of inherent viscosity, 0.2-0.25 dL/g. Upon addition of DMC at a later stage in the oligomer-forming reaction, an oligomer containing relatively higher carbonate end groups could be obtained. These oligomers gave polycarbonates higher inherent viscosity, 0.4-0.5 dL/g. It is therefore proposed that oligomers having carbonate end groups are more reactive in self-polycondensation than those containing acetate end groups. © 1995 John Wiley & Sons, Inc.     

Azo‐group labelled polyesters by end‐capping with 2‐oxazoline derivatives – preparation

Two azobenzene containing 2‐oxazolines were used for labelling of polyesters with carboxylic end groups by the end‐capping method. The reaction proceeded under the conditions of reactive processing, and in a solution. High conversions in melt were achieved in several minutes. The coupling of the modifiers was proved by NMR spectroscopy.     

Maleimide‐based thiol reactive multiarm star polymers via Diels‐Alder/retro Diels‐Alder strategy

Multiarm star polymers containing thiol‐reactive maleimide groups at their core have been synthesized by utilization of atom transfer radical polymerization (ATRP) of various methacrylates using a masked maleimide containing multiarm initiator. One end of the initiator contains multiple halogen groups that produce the star architecture upon polymerization and the other end contains a masked maleimide functional group. Unmasking of the maleimide group after the polymerization provides the thiol reactive maleimide core that is widely used in bioconjugation. Functionalization of the core maleimide group with a thiol containing tripeptide was used to demonstrate facile reactivity of the core of these multiarm polymers under reagent‐free conditions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2546–2556, 2010     

Preparation of telechelic oligomers by thermal degradation of propylene copolymers

The reactive end groups of nonvolatile oligomers obtained by controlled thermal degradation of poly(propylene-ran-ethylene) and poly(propylene-ran-1-butene) were determined by ¹H and ¹³C NMR spectroscopy. The molar ratio of unsaturated to saturated end groups was found to be about 9:1. The average number of unsaturated end groups per molecule was between 1.6 and 1.8, indicating that 60–80 mol% of the oligomer molecules were telechelic, having two terminal unsaturated end groups. These oligomers had a lower polydispersity than the raw material, despite their lower molecular weight and melting temperature. Although the end groups resulting from each monomer unit could be detected by ¹³C NMR, the end group composition differed from that of the main chains of the raw materials. The end group composition was satisfactorily explained by the differences in bond dissociation energy and activation energy of elementary reactions that occurred during thermal degradation, based on the monomer composition of the raw materials.     

Functionalized poly(methylphenyl)silane: End group reactivity

A Cl ended poly(methylphenyl) silane is synthesized and analyzed by ²⁹Si-NMR spectroscopy. The end groups are extremely reactive with small compounds as alcohols and amines. By this way, copolysilanes containing some nitrogen atoms can be synthesized. © 1996 John Wiley & Sons, Inc.