端基含108个己氧基偶氮苯介晶基元三代树状碳硅烷液晶研究

用发散法合成以四碳硅烷为核心,周边含108个己氧基偶氮苯介晶基元(M3)端基的三代树状碳硅烷(D3)液晶,并用元素分析、核磁共振、激光解吸电离飞行时间质谱、红外光谱、紫外光谱、偏光显微镜、差示扫描量热(DSC)和X射线衍射法(WAXD)进行表征.D3为向列相液晶,与M3相同,三代(D3)、二代(D2)和一代(D1)树状物的相态由介晶基元的相态决定.D3的液晶态相行为是K79N136I132N,D3的熔点比M3的低19℃,D3的清亮点比M3的增加16℃,D3液晶态温区比M3宽35℃.     

Reversible affinity interactions of antibody molecules at functionalized dendrimer monolayer: affinity-sensing surface with reusability

We described reversible affinity interactions of antibody molecules at a chemically functionalized electrode surface for a repeatedly renewable affinity-biosensing interface. Underlying biofunctionalizable monolayers were constructed with poly(amidoamine) dendrimers, whose surface chain-end groups were double-functionalized with biotinyl ligand and ferrocenyl groups for biospecific recognition and electron transfer reactions, respectively. Functionalized monolayers on gold electrodes provide platform surfaces for biospecific recognition reaction with monoclonal anti-biotin antibody molecules. Bound antibody molecules were dissociated from the surface via displacement reaction by the addition of free biotin in solution, enabling the affinity surface to be renewed and repeatedly utilized. Tracking of the association/dissociation reaction cycles were performed by registering the bioelectrocatalytic currents at the electrode using glucose oxidase (GOx) as a signal generator and ferrocenyl-tethered dendrimer (Fc-D) as an electron transferring mediator in electrolyte. Shielding of the affinity surface by biospecifically bound antibody molecules caused hindrance in electron transfer, resulting in reduced signal from cyclic voltammetry. By the displacement reaction using free biotin, bound antibody molecules were dissociated from the surface and the bioelectrocatalytic signal was restored. With the affinity surfaces constructed in this work, continuous association/dissociation reactions have been successfully accomplished, providing a possibility of reusable affinity biosensing interface.     

多巴胺用量对Fe3O4@PDA@PAMAM磁性纳米吸附材料的微观结构及吸附性能的影响

以自制的Fe3O4磁性纳米材料为核,多巴胺(DA)为表面修饰剂,成功地将2.0 G聚酰胺-胺(PAMAM)树状大分子接枝在Fe3O4磁核表面,制备出了一系列不同DA含量的Fe3O4@PDA@PAMAM磁性纳米吸附材料。采用X射线衍射仪(XRD)、红外光谱仪(IR)、振动样品磁强计(VSM)、透射电子显微镜(TEM)和电感耦合等离子体发射光谱仪(ICP-OES)等分析测试手段对材料组成、微观结构、磁性能和对重金属Cd(Ⅱ)离子的吸附性能进行了测试和表征。研究了修饰剂DA用量对Fe3O4@PDA@PAMAM磁性纳米吸附材料的相组成、微观结构、磁性能和吸附性能的影响。实验结果表明,Fe3O4@PDA@PAMAM磁性纳米吸附材料均呈典型的核-壳结构,材料晶型均呈现尖晶石结构,且壳层厚度随DA用量增加而增厚;材料的饱和磁化强度(Ms)均比Fe3O4的小,且随着DA用量的增加而降低,并且材料的矫顽力(Hc)和剩余磁化强度(Mr)均较低,其磁响应特性适合于做为可回收磁性纳米吸附材料。材料对Cd(Ⅱ)离子的平衡吸附容量随着DA用量的增加呈先增加后减小趋势。当Fe3O4和DA的质量比为8∶4时,吸附剂对Cd(Ⅱ)离子的吸附容量达到最大值165.13 mg·g^-1。     

Acetylcholine Biosensor Based on Dendrimer Layers for Pesticides Detection

We tested a new design of an enzyme biosensor based on acetylcholinesterase (AChE) and choline oxidase (ChO) immobilized on the supported monomolecular layer composed of poly(amidoamine) (PAMAM) dendrimers of the fourth generation (G4) mixed with 1‐hexadecanethiol (HDT). The resulting enzymatic activity, measured amperometrically, was substantially depressed in the presence of the organophosphate pesticide dimethyl‐2,2‐dichlorovinylphosphate (DDVP, Dichlorvos), carbamate pesticides carbofuran and carbamate drug eserine. The detection limits (1.3×10^?3 ppb for DDVP, 0.01 ppb for carbofuran and 0.03 for eserine) were considerably lower than so far reported for AChE based amperometric and potentiometric sensors. The relative simple protocol of biosensor preparation, high sensitivity and stability is very promising for determination of environmental pollutants in field conditions.     

Hyperbranched modification of unsaturated side chains of polyethylene introduced by γ-ray irradiation under a 1,3-butadiene atmosphere

 Amino and other functional groups were introduced to a polyethylene substrate starting from the unsaturated pendant and bridge groups (collectively called side chains) of polyethylene, which had been prepared by γ-ray irradiation under an atmosphere of 1,3-butadiene of the polyethylene substrate (the drawn film of ultra-high- molecular-weight polyethylene, Mˉv: 5 × 10⁶). 2-Aminoethylamino groups were introduced to the side chains through treatment either with bromine or with peracetic acid vapor followed by immersion in ethylenediamine. Introduction of amino groups were confirmed by Fourier transform IR spectrometry, ninhydrin test, and acid–base titration. Starting from 2-aminoethylaminated polyethylene, modification cycles to grow a dendrimer on the film were applied; these consisted of 2-methoxycarbonylethylation and 2-aminoethylamidation. This technique resulted in hyperbranched modification of the polymer. The product is a kind of dendrimer grown on the surface of polyethylene film with amplified amino ends and has anion-exchange capacity and absorbs acid dye. Its application in practical uses is discussed. Received: 31 March 2000 Accepted: 2 January 2001     

Insulated π-conjugated metallopolymers

Recently, there has been a progressive development of insulated π-conjugated metallopolymers with accumulated features of π-conjugated bridging units, transition metal complexes, and encapsulating moieties, as higher-order functionalized materials. A number of insulated conjugated metallopolymers have been successfully synthesized and their fascinating properties have been reported. In addition to the conventional features derived from π-conjugation and transition metals, their insulated structures can compensate for solubility, a disadvantage in conventional metallopolymers, and enhance their functionalities, such as sensing, luminescence, and conduction. In this review, we summarize the synthetic methodologies, structural characteristics, and functionalities of one-dimensional insulated π-conjugated metallopolymers, while focusing on the effect of transition metals and insulation on their properties.     

Oxidation of sulfides with hydrogen peroxide catalyzed by synthetic flavin adducts with dendritic bis(acylamino)pyridines

The catalytic activities of the cationic synthetic flavin adduct 1 with various dendritic and non-dendritic 2,6-bis(acylamino)pyridines 2 were examined for the oxidation of organic sulfides with H₂O₂. The adduct of 5-ethyllumiflavinium perchlorate 1a with 2b–d bearing poly(benzyl ether) dendron units acts as an efficient organocatalyst for the oxidative transformation of sulfides to the corresponding sulfoxides under mild conditions.     

Phosphorus-Containing Dendrimers: Synthesis and Properties

Several series of phosphorus-containing dendrimers have been designed to study the variation of their properties, depending on the type, the location (surface, branches, core, and cavities), and the number of functions implied.     

Fluorophore-labeled Polyamidoamine (PAMAM) Dendritic Architectures: Synthesis and Fluorescence Sensing Properties

Novel polyamidoamine (PAMAM) dendrimers (G=0.5–2.5) with a naphthalene core unit have been prepared. They were found to display acid as well as metal ion sensitive fluorescence signal amplification, making them of potential use as chemosensing materials. PAMAM dendritic wedges as well as naphthalene-centered PAMAM dendrimers were characterized by FT-IR, ¹H and ¹³C NMR spectroscopic methods and elemental analysis.