排序方式: 共有13条查询结果,搜索用时 62 毫秒
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首先采用4-氨基苯甲酸乙酯和MPEG-1000为原料,分别通过重氮化、醚化和水解反应合成了偶氮苯单体MPEG-1000-Azo-COOH;然后以3,4,5-三羟基苯甲酸甲酯和4-羟基吡啶为原料,通过醚化、水解和酯化反应制备了单体3,4,5-三-(n-十二烷氧基)苯甲酸-4-吡啶酯;最后将单体MPEG-1000-Azo-COOH和单体3,4,5-三-(n-十二烷氧基)苯甲酸-4-吡啶酯按摩尔比1:1进行氢键自组装,得到了目标聚合物.采用1H NMR、DSC、POM等对各单体和自组装产物的化学结构和相结构进行了表征.实验结果表明:通过多步化学反应成功制备了高纯度的目标单体和聚合物;通过氢键自组装获得的目标树枝状聚合物表现出更为丰富的相结构. 相似文献
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合成了三氰酸阴离子和硼酸为主体晶格的正四丁基铵阳离子包合物(n-C4H9)4N+.C3H2N3O3-.H3BO3,并通过单晶X射线衍射法对其进行了晶体结构测定.结果表明:晶体属三斜晶系,空间群为P1(No.2),a=0.973 99(16)nm,b=1.023 15(17)nm,c=1.293 2(2)nm,α=101.269(3)°,β=92.071(3)°,γ=98.155(3)°,Z=2,V=1.248 4(4)nm3,Dc=1.150 g.cm-3,μ(MoKα)=0.084 mm-1,F(000)=472,对5 010个独立衍射点的最终偏离因子R1=0.055 8.在标题化合物的晶体结构中,对称中心相连的三氰酸阴离子之间通过1对N—H…O氢键相连,形成沿b轴无限延伸的锯齿形长链.2个硼酸分子由1对O—H…O氢键连接,形成中心对称的二聚体.硼酸二聚体向外的2个羟基分别与邻近的三氰酸阴离子氢键长链通过O—H…O和O—H…N氢键连接,在(10 1)平面内形成无限伸展的波形氢键平面网格.四丁基铵阳离子穿插在氢键平面之间,形成类"三明治"式层状包合物. 相似文献
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将药物超分子化学的研究成果引入到有机化学实验教学中去。在学生完成阿司匹林的制备后,将阿司匹林与4,4’—联吡啶在有机溶剂中进行重结晶,制备出阿司匹林超分子化合物,利用熔点测定和红外光谱法对产物进行分析。 相似文献
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The property of the lowest excited triplet state of fluorenone (FL) in acetonitrile, ethyl acetate, toluene, cyclohexane has been investigated using time-resolved laser flash photolysis. The appearances of the corresponding cation radicals and anion radicals suggest that the electron transfer reaction occurs between 3FL* and amines. Experimental results show a decrease in the quenching rate constants along with reducing solvent polarity. The change of quenching rate constants of the FL excited triplet with the three N,N-dimethylaniline derivatives are explained using the Hammett constant. 相似文献
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基于氢键型自愈合树脂构建具备重复聚砂性能的水乳液型稳砂体系,以渗透率保留率和出砂临界流量为指标,考察乳液稳砂性能.结果表明:在130℃条件下,向填砂模型中注入1VP(VP为孔隙体积)乳液稳砂剂并养护12 h,砂柱液测渗透率保留率约为76.3%,出砂临界流量大幅度提升至110 mL/min,连续顶替100VP后,平均出砂... 相似文献
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Hellgren M Kaiser C de Haij S Norberg A Höög JO 《Cellular and molecular life sciences : CMLS》2007,64(23):3129-3138
Subunit interaction in sorbitol dehydrogenase (SDH) has been studied with in vitro and in silico methods identifying a vital hydrogen-bonding network, which is strictly conserved among mammalian SDH proteins. Mutation
of one of the residues in the hydrogen-bonding network, Tyr110Phe, abolished the enzymatic activity and destabilized the protein
into tetramers, dimers and monomers as judged from gel filtration experiments at different temperatures compared to only tetramers
for the wild-type protein below 307 K. The determined equilibrium constants revealed a large difference in Gibbs energy (8
kJ/mol) for the tetramer stability between wild-type SDH and the mutated form Tyr110Phe SDH. The results focus on a network
of coupled hydrogen bonds in wild-type SDH that uphold the protein interface, which is specific and favorable to electrostatic,
van der Waals and hydrogen-bond interactions between subunits, interactions that are crucial for the catalytic power of SDH.
Received 13 July 2007; received after revision 30 September 2007; accepted 1 October 2007 相似文献
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WANG Zhuo YU Yanxin ZHANG Deqing ZHU Daoben 《科学通报(英文版)》2006,51(16):1947-1954
1 Introduction It is well known that nucleobases are very important biological molecules. Sensitive and selective probes for nucleotides and nucleobases are highly desirable. A number of modified nucleobases and nucleotides as well as artificial hosts wit… 相似文献
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Constructing supramolecular nanostructure by hydrogen-bonding 总被引:1,自引:0,他引:1
YiBao Li QingDao Zeng ZhiHui Wang GuiCun Qi Li Guan XiaoLin Fan Chen Wang 《科学通报(英文版)》2008,53(10):1613-1616
The diquinoxalino (2.3-2".3"-a.c) phenazine (DQP), containing 6 nitrogen atoms, was synthesized, and its adsorption and self-assembling behavior on highly oriented pyrolytic graphite (HOPG) was studied by scanning tunneling microscopy (STM) under ambient conditions. With 1,14-tetradecanedioic acid as a bridge, uniform two-dimensional arrays of 1,14-tetradecanedioic acid/DQP nanostructure were successfully fabricated. The result illustrates that it is possible to construct and control supramolecular nanostructure by intermolecular hydrogen-bonding. 相似文献