Preparation and applications of novel fluoroalkyl end-capped acrylamide oligomers/polythiophene nanocomposites

Thiophene monomer reacted with ferric chloride in the presence of a variety of fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers [R_F-(DOBAA)_x-R_F] to afford nanometer size-controlled R_F-(DOBAA)_x-R_F oligomers-polythiophene composites [R_F-(DOBAA)_x-R_F/PTh]. R_F-(DOBAA)_x-R_F/PTh nanocomposites thus obtained were demonstrated to have a good dispersibility and stability in methanol to give a transparent brown solution. In addition, these fluorinated nanocomposites were applied to the surface modification of common organic polymers such as poly(methyl methacrylate), and were dispersed regularly above the polymer surface.     

Specific hydrolysis of DNA by Ce~(4+) -ODN hybrid

The cerium complex bound to the derivative of oligoDNA has been synthesized successfully that can hydrolyze DNA with sequence-specificity. The synthesized derivative of oligoDNA, 5'-EDTA-P-10 mers ODN, was demonstrated by HPLC. The fluorescence spectrum of Tb3+ was detected after its interaction with the hybrid of 10-mers ODN and 26-mers ODN and the results show that the artificial endo-enzyme can recognize and combine firmly with the substrate DNA. The electrophorogram shows that the cerium-oligoDNA hybrid can specifically hydrolyze its substrate DNA and the cleavage site of this hydrolysis reaction is also discussed. This artificial nuclease can be widely used in molecular biology and genetic engineering as one kind of endo-enzyme.     

环状聚芳酯低聚物的核磁共振谱峰的归属

本文报道了环状聚芳酯低聚物的核磁共振碳谱及氢谱。测定了其碳及氢的自旋晶格驰豫时间，通过与类似物质标准谱图的比较、自旋晶格驰豫时间的分析以及化学位移取代基效应的计算等，归属了其碳氢谱峰。     

对硝基苯酚亚甲基桥齐聚物的苯并二(口恶)环衍生物的合成

本文研究了二(对硝基苯氧基)-甲烷或对硝基苯酚在浓硫酸的存在下与过量多聚甲醛的反应,合成得到含两个和三个苯环的对硝基苯酚亚甲基桥齐聚物的苯并二噁环衍生物。柱层析分出四个纯品,经IR,~1H NMR,MS分析鉴定,其中三个为新化合物。这类化合物作为合成子可用于硝基取代的杯芳烃或长链亚甲基桥齐聚物的收敛性分步合成。     

Synthesis and Thermal Properties of a Novel Schiff Base Oligomer with a Double Azomethine Group and its Co(II) and Mn(II) Complexes

Schiff base oligomer of N,N′‐bis (2,4‐dihydroxybenzylidene) 1,2‐phenylenediamine (DHBPDA), with a double azomethine group, was synthesized from the oxidative polycondensation (OP) reaction with NaOCl as an oxidant in an aqueous alkaline medium at 90°C. About 75% DHBPDA was converted to O‐DHBPDA. The structures of the products were studied by UV‐Vis, FT‐IR, ¹H‐NMR, ¹³C‐NMR and elemental analysis. According to Gel Permeation Chromatography (GPC) analysis of O‐DHBPDA, the number average molecular weight (M_n), weight average molecular weight (M_w) and PDI values were found to be 4328 g mol^?1, 6228 g mol^?1 and 1.43, respectively. TG/DTA analyses were shown to be stable of O‐DHBPDA against thermo‐oxidative decomposition. During the polycondensation reaction, a part of the azomethine (‐CH?N‐) groups oxidized to aldehyde (CHO) group (10–12%). Oligomer‐metal complexes of oligo‐N,N′‐bis (2,4‐dihydroxybenzylidene) 1,2‐phenylenediamine (O‐DHBPDA) with Co(II) and Mn(II) were synthesized and characterized by FT‐IR, UV‐Vis, TG‐DTA and Atomic Absorption Spectroscopy (AAS). The residue of DHBPDA, O‐DHBPDA, O‐DHBPDA‐Co and O‐DHBPDA‐Mn were found to be 0%, 3.65%, 11.67%, and 9.20%, respectively at 1000°C.     

A Stepwise Synthesis of Diversified Phosphazene Oligomers

Abstract

A stepwise approach to oligophosphazenes in which substituents at each phosphorus of the backbone can be diversified is described, through new N-chloroaminophosphorus compounds. Heterophosphazenes have also been obtained.     

Single-Fluorophore Dynamic Imaging in Living Cells

Recently, observation and tracking of single fluorophores, which we term single fluorophore dynamic imaging (SFDI) in this review, in living cells have been achieved. In particular, the recent success of SFDI of individual proteins tagged with green fluorescent protein (GFP) in live cells has opened new important possibilities for studying events occurring in living cells at the level of single molecules. Specifically, SFDI of GFP allows the tracking of movement and oligomerization levels of individual oligomers (monomers) in living cells and, thus, provides powerful means to investigate the movement, assembly, localization, and activation that signaling molecules undergo following an external stimulus. In this short account, we first review technologically important points for SFDI of GFP molecules in living cells, then give examples of its application, and, finally, propose a synergistic use of SFDI and single-particle tracking, a technique used for investigating single or small groups of molecules in live cells over the past 15 years.     

Preparation of novel cross-linked fluoroalkyl end-capped adamantane cooligomer/copper nanocomposites

Copper(II) oxide reacted with hydrazine in the presence of fluoroalkyl end-capped oxime-blocked isocyanato cooligomer containing adamantyl segments at 90 °C for 30 min in ethylene glycol, and the deprotecting reaction of the cooligomer in the resulting product at 120 °C for 15 min was found to afford the colloidal red-brown colored cross-linked fluorinated cooligomer/Cu nanocomposites, which were stabilized by fluoroalkyl end-capped cooligomer containing benzotriazole segments. On the other hand, the corresponding cross-linked fluorinated cooligomer possessing no adamantyl segments could not afford the copper nanocomposites under similar conditions. Dynamic light scattering measurements and TEM photography of these cross-linked fluorinated cooligomer/Cu composites showed that these composites are nanometer size-controlled very fine nanoparticles. These fluorinated Cu nanocomposites have a good dispersibility and stability in mixed solvents of ethylene glycol and methanol for two weeks under air atmosphere conditions. In addition, these fluorinated Cu nanocomposite powders have been found to be stable for more than three months.     

Synthesis of optically active oligomers consisting of chiral phosphorus atoms: capture of an intermediate between a polymer and a small molecule

We describe here the synthesis and properties of novel optically active oligophosphines. The effect of the number of chiral phosphorus atoms on thermal properties and conformations is documented. In this study, we captured an intermediate between a polymer and a small molecule. To the best of our knowledge, it is primarily observed that a small molecule transforms into a polymer via an amorphous small molecule during the process of the elongation of the oligomer main chain.     

One-step syntheses of alkyl glycosides and alkyl-substituted DNA oligomers by chemoselective glycosidations using DNA bases

The simple and practical synthesis of alkyl glycosides by novel chemoselective glycosidations using natural resources, DNA and RNA nucleosides, was realized, and the one-step synthesis of chemoselectively modified DNA oligomers using the glycosidation method was also demonstrated.