Synthesis of 5-(1,2,3-triazol-4-yl)-2'-deoxyuridines by a click chemistry approach: stacking of triazoles in the major groove gives increased nucleic acid duplex stability

A general protocol for converting alkyl and aryl halides into azides and for converting these in situ into 1,4-disubstituted triazoles was applied with 5-ethynyl-2'-deoxyuridine. This afforded three modified 2'-deoxyuridine analogues with either unsubstituted or 1-phenyl-/1-benzyl-substituted triazoles in their 5-positions. Modelling demonstrates coplanarity of the two heteroaromatic rings, and UV spectroscopy showed the uracil pK(a) values to be almost unchanged. The three nucleosides were introduced into nonamer oligonucleotides by phosphoramidite chemistry. The heteroaromatic triazoles became positioned in the major grooves of the short dsDNA and DNA-RNA duplexes. While single modifications led to decreased duplex stability, the stacking of four consecutive modifications led to enhanced duplex stability, especially for DNA-RNA duplexes. The duplex structures were studied by CD spectroscopy and molecular dynamics simulations, which supported the conjecture that the duplex stabilizing effect is due to efficient stacking of the heteroaromatic triazoles.     

Synthesis and photo‐curing behaviors of silicon‐containing (vinyl ether)–(allyl ether) hybrid monomers

A series of silicon‐containing (vinyl ether)–(allyl ether) hybrid monomers used in nano‐imprint lithography resists were synthesized and subjected to photo‐initiated polymerization. The surface energies of the monomers and the resulting polymer films were then investigated. The surface energies of the monomers were very low at less than 15 mJ m^–2. The photo‐curing behaviors of the five hybrid monomers were investigated using real‐time Fourier transform infrared spectroscopy. The monomers were sequentially initiated with cationic (PAG201) and mixed (cationic initiator PAG201, radical initiator ITX or TPO) initiators. The vinyl ether double bond polymerized both rapidly and completely, whereas the allyl ether double bond remained when PAG201 was used as the photo‐initiator and polymerized completely with mixed initiators. The different double bonds of the silicon‐containing (vinyl ether)–(allyl ether) hybrid monomer increased the efficiency of the polymerization and overcame the intrinsic limitations of the free radical and cationic polymerization processes, including strong oxygen inhibition, large volume shrinkage and high humidity sensitivity. The five monomers with low viscosity, low surface energy, good thermal stability and good photo‐polymerization properties were suitable for nano‐imprint photoresists. © 2013 Society of Chemical Industry     

Thermally reactive liquid crystalline copolymers based on 11-[(4-cyano-4′-biphenyl)oxy]undecanyl vinyl ether and 2-vinyloxyethyloxy methacrylate

Summary Living cationic copolymerization of 11-[(4-cyano-4-biphenyl)oxy]undecanyl vinyl ether (6-11) with 2-vinyloxyethyloxy methacrylate (16-2) leads to reactive copolymers poly[(6-11)-co-(16-2)]X/Y (where X/Y is the mol ratio between the two monomers in copolymer) containing methacryloyl side groups. Upon thermal crosslinking via the polymerization of their methacryloyl side groups, the copolymers with X/Y=5/5 to 9/1 lead to liquid crystalline networks displaying a S_A mesophase. These results have demonstrated that a shorter spacer in the reactive bifunctional monomer 16-2 than in the mesogenic 6-11 monomer leads to networks with broader range of mesomorphism than those derived from a reactive monomer containing a spacer length equal to that of the mesogenic monomer.This paper is part 27 in the series: Molecular engineering of liquid-crystalline polymers by living polymerization. Part 26: V. Percec, Q. Zheng: Polym. Bull., previous paper in the issue     

乳化环氧改性的丙烯酸系乳液室温固化体系

将乙二醇二缩水甘油醚分散在水中制成环氧化合物乳液,并以其为交联剂,用以对丙烯酸系单体/胺基单体乳液共聚物的改性,制成了双组分室温固化乳液涂料。研究了乳化剂种类和胺基单体用量对聚合稳定性的影响,结果表明,若采用p 壬基酚聚氧化乙烯醚硫酸钠为乳化剂,且胺基单体用量低于单体总量2 5%时,可以制得稳定的带胺基的共聚物乳液。将丙烯酸系共聚物乳液和环氧乳液复合并在室温下干燥成膜,通过对聚合物膜的DSC和力学性能测试均表明,双组分体系在成膜过程中发生了交朕反应,而未加环氧化合物的单组分聚合物乳液成膜时则不发生交联。     

苯骈噻吩酮衍生物甲川型分散染料的研究(Ⅰ)染料分子结构与吸收光谱

本文测定了一系列苯骈噻吩酮衍生物甲川型分散染料在溶液中的吸收光谱,研究了这类染料的分子结构与吸收光谱之间的关系.     

Synthesis of novel highly reactive silicone-epoxy monomers for cationic photopolymerizations

A series of novel cationically photopolymerizable silicone-epoxide monomers bearing substituted benzyl ether groups were prepared. Monomers with methoxy groups on the aromatic ring of the benzyl ether group were synthesized by sequential hydrosylation reactions of 1,1,3,3-tetramethyl disiloxane. Kinetic studies using real-time infrared spectroscopy of the cationic photopolymerizations of these novel monomers showed that those monomers with methoxy groups exhibited elevated rates of photopolymerization. The acceleration effect was explained on the basis of synergistic effects of two mechanisms, namely, the normal ring opening polymerization catalyzed by a Brönstead acid, and the cationic photopolymerization induced by the redox interaction between the free radicals formed in the backbone of the monomer and the onium salt used as photoinitiator. The methoxy groups on the aromatic ring of the benzyl ether enhance the stabilization of the carbocation formed in the structure of the monomer. Silicone-epoxy monomer with 2,5-dimethoxybenzyl ether group exhibited the higher photopolymerization rate. The latter compound can also be used as accelerator of the cationic photopolymerization of commercial silicone-epoxy monomer when used in low concentrations.     

Synthesis and cationic photopolymerization of fluorine‐containing vinyl ether monomers for the hydrophobic films

Fluorine‐containing vinyl ether monomer is a combination of UV‐curing technology and low surface energy materials. In this article, a type of fluorine‐containing vinyl ether monomer was synthesized by the reaction of fluorinated alcohols, hexafluorobenzene, 2‐vinyloxy ethanol, and sodium hydride. These monomers exhibit low viscosity and good fluidity. The effect of the fluorine content of the monomers on their UV‐curing behavior was monitored by photo‐differential scanning calorimetry. The photo‐polymerization process was efficient because the double‐bond conversed sufficiently (>85%) and the curing rate was fast (<20 s). In addition, the surface energy of homopolymer and copolymer films was researched. The surface free energy was very low and could even reach 0.92 mJ m^?2. The low surface energy was due to high fluorine content and the diffusion of uncured monomers, which was on the basis of X‐ray photoelectron spectroscopy data and observed conversions. The structure of homopolymers and copolymers was one of the most important influences on the surface free energy and the thermal properties. The copolymers exhibited better thermal stability than the homopolymers. All of these results demonstrated that these monomers are suitable for a wide range of practical applications such as UV coatings, UV inks, and photoresists. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41019.     

含异氰脲酸酯结构聚醚多元醇的合成

以1,3,5-三羟乙基异氰脲酸酯(THEIC)为引发剂、三氟化硼乙醚络合物为催化剂,环氧化合物为环单体,进行了阳离子开环聚合反应的研究.发现THEIC与环氧单体可在非均相体系中平稳地进行阳离子开环聚合反应.在THEIC体系,就链引发而言,环氧氯丙烷的大于环氧丙烷、丁基醚环氧乙烷.调整环单体加料次序就可以获得嵌段共聚醚多元醇.     

Ion-Pair Sorption of Alkali Metal Chlorides by Crown Ether Carboxamide Resins

Abstract

Ten crown ether carboxamide resins are prepared by condensation polymerization of N,N-dialkyl sym-(R)dibenzo-16-crown-5-oxyacetamide monomers with formaldehyde in formic acid. Competitive ion-pair sorption of alkali metal chlorides from aqueous methanol solutions by these novel resins reveals that both sorption selectivity and efficiency are influenced by: 1) the conformational positioning of the pendant carboxamide group with respect to the crown ether cavity; 2) the length of the N,N-dialkyl chains on the pendant carboxamide group; 3) the methanol content of the aqueous methanol solution; 4) the concentration of alkali metal chlorides in the sample solution; and 5) the temperature of the sample solution. The highest sorption efficiency and Na⁺ selectivity are obtained for a resin prepared from N.N-dibutyl sym-(propyl)dibenzo-16-crown-5-oxacetamide monomer in which the geminal propyl group orients the carboxamide-containing side arm over the crown ether cavity. Lengthening the alkyl chains in the carboxamide group is detrimental to both sorption efficiency and selectivity. A very sharp response of alkali metal chloride sorption to the methanol content of the sample solution is noted for the crown ether resins which possess preorganized carboxamide side arms.     

Polymerization of N-vinylcarbazole over cobalt (II) exchanged 13X molecular sieves

Polymerization of N-vinylcarbazole over Co(II)-13X molecular sieves in toluene solution has been studied. The rate of polymerization has been observed to be second order both in monomer concentration and in the exchange level of Co(II), and linearly dependent on catalyst loading. An apparent activation energy of 8.71 kcal mol^?1 (36.41 kJ mol^?1) has been found for the polymerization. The effect of different parameters on molecular weight has also been studied. The general kinetic features of the reaction are somewhat different from those reported for monomers like isobutyl vinyl ether, styrene etc. on simple and rare earth exchanged 13X molecular sieves.     

电泳显示器用聚合物包覆颗粒的制备及其分散稳定性的紫外透光率表征

采用自由基接枝聚合法,将不同极性的单体修饰在黑色无机颜料颗粒表面,以紫外透光率法为主要表征手段,考察了聚合物包覆层的组成结构对颗粒在电泳体系中分散稳定性的影响. 结果表明,聚合物修饰后颗粒稳定时间至少提高5倍,且随所用包覆单体侧链长度增大而增大. 当单体支链的碳原子数大于4时,颗粒能很好地长时间分散在非水体系中. 所制黑白电泳显示器在5 V电压下,响应时间小于1 s,对比度达(4~5):1. 本结果为提高缺乏理论研究的电泳显示体系的分散稳定性和电泳显示效果及使用寿命提供了研究基础.     

硫杂冠醚对Ag(I)和Tl(I)的萃取

基于冠醚的配位化学及软硬酸碱理论,设计并合成了五种硫杂冠醚,系统研究了其对Ag(I)和Tl(I)两种软酸离子的络合能力.模拟计算结果表明,五种冠醚与Ag(I)和Tl(I)络合后构型均发生了转变,且结构优化后的五种冠醚与Ag(I)络合过程的ΔG和ΔU均较负,表现出了一定的配位能力,而与Tl(I)络合过程的ΔG和ΔU均接近...     

Modification of poly(vinyl cinnamate) photo-alignment layers using polymerizable mesogens

Polymerizable mesogens were blended with poly(vinyl cinnamate) (PVCi) in order to improve the alignment properties of liquid crystals (LC) on the layer surface. Two types of cyanobiphenyl monomers, which have short (n=0) and long (n=11) spacers, were prepared, respectively. Polarized UV exposure at the elevated temperature increased the inclusion of the monomers into the network of the photo-products. Compositional studies showed that the short-spacer monomer improved homogeneous LC alignment and thermal stability, whereas the long-spacer monomer contributed to generate homeotropic LC alignment.     

Synthesis and characterization of novel (sulfonated) poly(arylene ether)s with pendent trifluoromethyl groups

This paper reports the synthesis of four different trifluoromethyl-substituted poly(arylene ether)s on the basis of 2,2-bis(4-hydroxyphenyl)hexafluoropropane (bisphenol AF) and various difluoro- or dinitrobiphenyl or terphenyl monomers in the course of a step-growth polycondensation. Besides a comparison between the polymerisability of the different monomer combinations, a main focus of this work lies on the NMR characterization of these poly(arylene ether)s. Poly(arylene ether)s with sufficiently high number average molecular weights were sulfonated by fuming sulfuric acid or chlorosulfonic acid and investigated in terms of membrane properties relevant for fuel cell applications.     

Preparation of acrylic copolymer latex modified by fluorine,silicon, and epoxy resin

A series of modified acrylic copolymer latices have been prepared through a semicontinuous emulsion copolymerization process with a variety of hydrocarbon monomers and (perfluoroalkyl) methyl methacrylate, vinyltriethoxysilicone, and phenol‐formaldehyde epoxy resin. The composition of copolymer was analyzed by fluoride ion selective electrode analysis, ¹⁹F NMR, FTIR, crosslinking degree determination, and epoxy‐acetone method. The results showed that the fluorine monomer, silicon monomer and epoxy resin had copolymerized with acrylic monomers. The optimum mass ratio between the curing agent TEA and epoxy resin was 1.36 : 6. The determination results of stabilities (electrolyte stability, freeze‐thaw stability, high temperature stability and mechanical stability) of latices showed that the incorporation of fluorine monomer and silicon monomer improved freeze‐thaw stability and mechanical stability, whereas the epoxy resin did not have obvious effect on the stabilities. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and adsorption properties for metal ions of mesocyclic diamine‐grafted chitosan‐crown ether

A new type of grafted chitosan‐crown ether was synthesized using mesocyclic diamine crown ether as the grafting agent. The C2 amino group in chitosan was protected from the reaction between benzaldehyde and chitosan to form N‐benzylidene chitosan (CTB). After reaction with mesocyclic diamine crown ether of the epoxy propane group to give mesocyclic diamine‐N‐benzalidene chitosan (CTBA), the Schiff base was removed in a dilute ethanol hydrochloride solution to obtain chitosan‐crown ether (CTDA). Its structure was confirmed by FTIR spectra analysis and X‐ray diffraction analysis. Its static adsorption properties for Pb(II), Cu(II), Cd(II), and Cr(III) were studied. The experimental results showed that the grafted chitosan‐crown ether has high selectivity for the adsorption of Cu(II) in the presence of Pb(II), Cu(II), and Cd(II) and its adsorption selectivity is better than that of chitosan. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1255–1260, 2000     

聚醚多元醇为分散介质γ射线辐射制备St–AN共聚微球

以苯乙烯(St)和丙烯腈(AN)为单体,用大分子单体法和γ射线辐射技术制备了St–AN共聚微球,并用傅里叶红外光谱(FT–IR)、扫描电子显微镜(SEM)、X射线衍射(XRD)和热重分析(TGA)等方法对制得的微球进行了分析表征。结果表明,大分子单体和吸收剂的量都会影响到微球的形态结构、物相结构和热稳定性。在吸收剂量25 kGy条件下用不同大分子单体制得微球的形态结构表现出更明显的差异,在较低吸收剂量(5 kGy)下制得微球的XRD谱图中的肩状衍射峰更明显,较高吸收剂量(25 kGy)下制得的微球具有较好的热稳定性。     

New biosourced AA and AB monomers from 1,4:3,6-dianhydrohexitols,Isosorbide, Isomannide,and Isoidide

In the present work, we propose the synthesis of a new family of sugar derived 1,4:3,6-dianhydrohexitol based AA/AB-type monomers. Unprecedented diacids based on Isomannide and Isoidide were elaborated with high yields and showed interestingly high melting point ranges (240–375 °C). Optimization of reaction conditions (temperature, time of reaction, and reactant ratios) has been investigated to synthesize the key intermediate of a set of AB monomers with acid, ester, and acid chloride functionalities. Isosorbide based ether benzoic acid AB monomer was polymerized and characterized by NMR and DSC techniques. The results show a semicrystalline behavior of the obtained polymer thanks to the controlled stereoregular arrangement of the AB starting monomer.     

AM/SAA共聚反应合成HPAM分散液研究

以丙烯酰胺与丙烯酸钠为原料,在聚乙二醇水溶液中合成了聚丙烯酰胺(HPAM)分散液。考察了初始单体浓度、共聚单体与聚乙二醇摩尔配比、共聚单体摩尔配比、聚合反应温度、乳化剂种类以及用量对HPAM分散液稳定性以及特性粘数的影响。结果表明,共聚单体与聚乙二醇摩尔配比、聚合反应温度、乳化剂种类以及数量对合成HPAM分散液的稳定性以及HPAM特性粘数都有较大影响;初始单体浓度对HPAM分散液的稳定性影响较小,但对HPAM特性粘数有一定影响;采用Span80和Tween80复配作为乳化剂效果好,确定HPAM分散液体系的最佳HLB值为9.65。     

Synthetic detergents from animal fats. VII. Detergent combinations

Summary Laboratory measurements of detergency were made on mixtures of sodium salts of sulfated hydrogenated tallow alcohol (X), disodium salts of α-sulfonated hydrogenated tallow acids (Y), sodium dodecylbenzenesulfonate (Z), and a builder (B) using three different kinds of standard soiled cotton. Component X was the most important, and mixtures not containing X were generally inferior detergents. Built XY mixtures were better than XZ mixtures with one kind of soiled cotton (cloth I). Built XZ mixtures were better than XY mixtures with another soiled cotton (cloth III). The results, based on laboratory measurements of detergency using standard soiled cotton, are suggestive rather than conclusive. Partial substitution of X by Y or Z, or by both Y and Z, may be possible without loss in detergency. Presented at the meeting of the American Oil Chemists’ Society, Houston, Tex., April 1956. A laboratory of the Eastern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.