Synthesis of Novel Carbosilane Dendrimers Based on Pentaerythritol

Novel pentaerythritol-based carbosilane dendrimers centered at carbon have been synthesised. Starting from tetraallyl ether based upon pentaerythritol as the core molecule, a succession of alternate Pt-catalyzed hydrosilylation of allyl groups with HSiC13 and allylations of SiC1 groups thus introduced with CH2=CHCH2MgBr in THF provided a divergent synthesis of three generations of carbosilane dendrimers in which the Si atoms are linked by CH2CH2CH2 groups. The reaction conditions for hydrosilylation must be well controlled. After purification by chromatography on silica gel pure products for each generation were obtained. The IR, ^1H and ^13C NMR spectra and elemental analysis data are consistent with the proposed structures. The molecular weights of the resulting carbosilne dendrimers have been determined by vapor pressure osmometry.     

Pentaerythritol-based Carbosilane Dendrimers

A series of novel pentaerythritol-based carbosilane dendrimers have been synthesized. Using pentaerythritol-based tetraallyl ether as core molecule, the dendrimers have been prepared up to the third generation with I08 allyl groups on the periphery by alternate allylation-hydrosilylation approach.     

The Preparation of the Carbosilane Dendrimers with Pentafluorophenyl Groups

Dendrimers as intriguing macromolecules possess potential in phase transfer catalysis, hosts-guest chemistry, controlled release drugs or might serve as recyclable extracting agents1,2,3. The fluorine-containing dendrimers can be used as low surface-energ…     

Synthesis of Alkoxysilanes Bearing β—Diketone Group through Hydrosilylation

Alkoxysilane bearing diketone group was synthesized by hydrosilylation of 3-allyl acetylacetone. It was indicated by the ^1H NMR spectrum that the C=O group does not interfere with the synthesis.     

Synthesis of New Chrial Building Blocks for Novel Peptide Nucleic Acids

N-Boc protected amino acids of analogues of peptide nucleic acid (PNA),which are a class of conformationally constrained building blocks based on 4-aminoproline backbone with chirality at 2-c and 4-c,have been synthesized.Those monomers can be used for the construction of novel peptide nucleic acid analogues.     

Synthesis and Characterization of Novel Aliphatic Polycarbonates Bearing Pendant Allyl Ether Groups

To fulfill the diverse requirements in surgery and medicine, biomedical polymers have been drawing interests and attentions increasingly since the last decade1. In these fields, aliphatic carbonates have been proved to be a kind of material with excellent…     

A Novel Pentaerythritol-based Carbosilane Liquid Crystalline Dendrimer Containing 12 Nitroazobenzene Groups on the Periphery

A novel liquid crystalline dendrimer with peripheral mesogenic units was successfully prepared. Azo-reaction and Williamson synthesis were employed in the preparation of the mesogenic unit 4-[4-(6-hydroxyhexyloxy)-phenylazo]nitrobenzene (M-NO2). A terminal Si-Cl functional carbosilane dendrimer based on pentaerythritol was used as dendritic scaffold and subsequently functionalized with the aforementioned groups. Investigation of the liquid crystalline properties of the mesogen-functionalized dendrimer PCSi-IG-NO2 by polarizing optical microscopy, DSC, and X-ray diffraction showed that it exhibits smectic E (SE) phase, different from the corresponding mesogenic unit, which shows nematic phase. Furthermore, the temperatures of both the melting point and the clearing point of the mesogen-functionalized dendrimer decrease, and the temperature region of the SE phase is wider than that of the nematic phase.     

Simple and Clean Synthesis：Tin—mediated Allylation of Carbonyl Compounds in Water

Tin-mediated allylation of aldehydes or ketones in distilled water gives rise to the corresponding homoallyl alcohols in higy yield without assistance such as heat ,supersonic and acidic media.     

Synthesis and characterization of α-N,N-dihydroxyethylaminopropyl-ω-butylpolydimethylsiloxanes

A series of α-N,N-dihydroxyethylaminopropyl-ω-butylpolydimethylsiloxanes with different molecular weight were synthesized. The preparation included five steps which were hydroxyl protection, alkylation, anionic ring-opening polymerization, hydrosilylation and deprotection. The structure of reaction products was characterized by FT-IR, GC, 1H NMR. 2007 Qing Si Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

Synthesis of Calix [4] resorcinarene Core Dendrimers with Peripheral Salicylideneimine Functional Groups

IntroductionOver the past two decades, dendrimers have at-tracted considerable attention because of their inherentnovel structural features and their potential applicationsin various scientific and industrial fields such as cataly-sis or newmaterials, and…     

基于1,6-己二醇的哑铃型树状大分子

Novel carbosilane dendrimers based on 1,6-hexanediol were prepared by divergent approach. Using 1,6-hexanediol-based diallyl ether as the core molecule, the dendrimers were prepared to the third generation with 54 allyl groups on the periphery by alternate hydrosilylation-allylation reactions.     

树枝状碳硅烷涂层电色谱柱的制备及其评价

利用碳硅烷树枝状大分子末端SiCl键的高反应活性和多官能团性,将β-环糊精固定到毛细管柱上,制备了一种新型的手性毛细管电色谱柱。本涂层柱性能稳定,使用寿命长,经过1个月的连续运行,柱效能损失率低于5%。优化分离条件,采取16kV分离电压、检测波长214nm、10cm位差进样7s和40mmol/L磷酸盐缓冲体系,分离扑尔敏、盐酸异丙嗪和苯丙胺手性异构体,其中G2P代柱子对扑尔敏分离柱效达到2.5×105Plates/m,分离度RS=1.43,基线分离,取得了较满意的分离效果。     

Mechanical Properties of Silicone Rubber Using Carbosilane Dendrimers as the Cross-linker

Peroxide-cured high-temperature vulcanized （HTV） silicone rubber was prepared by using allyl-capped carbosilane dendrimers, in which the core molecule is Si（CHaCH=CH2）4, as the cross-linker. It showed that this kind of allyl-capped carbosilane dendrimer improved the mechanical properties of silicone rubber.     

碳硅烷树枝状化合物的功能化研究

本文根据碳硅烷树枝状化合物功能基的种类及反应特性,介绍了有关含硅树枝状化合物的功能化的方法,并对功能化含硅树枝状化合物的用途做了相应评述.     

含不同核心第一代π-共轭不对称树状化合物的合成

以3,5-二叔丁基苯酚、三氟甲基磺酸酐和4,5-二乙炔基-2-甲氧基苯酚为原料,合成了4,5-双（3′,5′-二叔丁基苯基乙炔基）-2-甲氧基苯酚（单分子枝）,单分子枝的酚羟基用三氟甲基磺酸酐酯化得到磺酸酯,后者再分别与偶氮苯、联苯、蒽和芘发色团偶联,得到含不同核心的第一代π-共轭不对称树状化合物。 目标化合物的组成和结构分别经1H NMR谱、13C NMR谱、IR光谱和元素分析予以表征。 其溶解性测试表明,相对于核（不同的发色团）,所有树状化合物均能溶于常用的有机溶剂,并显示出良好的热稳定性。 这将有利于其掺杂入其它材料和器件中。     

外围含对-硝基偶氮苯介晶基团的椭球型硅碳烷树状物

Novel carbosilane liquid crystalline dendrimers based on 1,6-hexanediol were prepared. Using the precursors Gn-C1 （n = 1-3） with Si-C1 bonds on the periphery as dendritic scaffolds and 4-[4-（6-hydroxyhexyloxy）phenylazo]- nitrobenzene as mesogenic group, a series of carbosilane liquid crystalline dendrimers from the first to the third generation were synthesized. These carbosilane liquid crystalline dendrimers showed smectic phase.     

Carbosilane dendrimers NN8 and NN16 form a stable complex with siGAG1

A new mechanism of gene expression inhibition has been discovered as RNA interference, in which the ability of double-stranded RNA to stimulate specific degradation of an mRNA target with a complementary sequence to one of the double-stranded RNA strands. Water-soluble carbosilane dendrimers containing ammonium or amine groups at their periphery are biocompatible molecules that may be good candidates as non-viral carriers of small interfering RNA. In studying the formation of complex between anti-HIV siRNA siGAG1 and carbosilane dendrimers NN8 and NN16 by circular dichroism, fluorescence, and zeta-potential, the size of nanoparticles formed has been estimated by dynamic light scattering. At a charge ratio of 1:3-4 (siGAG1:dendrimer), the dendriplexes formed were in the size range of 250-350 nm.