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1.
本文构建了一种基于分子信标自由末端现场标记电活性信号分子的新型DNA传感器.首先将3′修饰巯基的分子信标通过Au–S键自组装到金电极表面,然后在修饰有羧基的5′自由末端通过共价偶合和配位作用依次组装上三聚氰胺(Mel)和铜离子(Cu2+),得到以Mel-Cu2+配合物为电活性信号源的分子信标.该方法简单实现了电活性分子信标的标记、分离和纯化.以[Fe(CN)6]3-/4-为电化学探针,采用循环伏安和电化学阻抗法对层层自组装过程进行了表征.杂交实验表明,Mel-Cu2+信号源所对应的峰电流强度随着杂交液浓度的增大逐渐降低,且氧化峰电流与互补序列浓度对数在1.0×10-15~1.0×10-9 mol/L范围内呈良好的线性关系.根据3σ计算得到检测限为2.4×10-16 mol/L.另外,由于分子信标特殊的茎环结构特征和Mel-Cu2+信号源稳定的无机配位组成,传感器显示了很高的特异性、再生性和稳定性.  相似文献   

2.
聚合诱导自组装是一种基于活性聚合的新型自组装策略,其特点是可以在较高固含量体系中一步制备不同形貌的聚集体结构.利用可逆加成-断裂链转移聚合(RAFT)活性聚合,在乙醇溶液中合成新型P4VP-b-PBz MA嵌段共聚物,发现聚合诱导自组装过程中聚集体结构发生球→蠕虫→囊泡的连续转变.亲溶剂链段P4VP的变化可有效调控聚集体的结构和尺寸.此外,采用无规共聚方法,研究了P4VP-b-(PHPMA-co-PBz MA)三嵌段共聚物在聚合诱导自组装过程中组装体结构的转变过程.  相似文献   

3.
自组装分子凝胶的原位光聚合及其聚合物研究   总被引:4,自引:1,他引:3  
黎坚  王理  殷以华  杨亚江 《化学学报》2002,60(9):1700-1706
合成了一种以二胺为基础的可聚合凝胶因子4,4’-二(α-甲基丙烯酰氧基- 1,3-亚乙氧基羰基丙酰氨基)二苯甲烷(BMDM),利用在特定结构区域的非共价 键相互作用自组装形成有序的三维纤维网络,使有机溶剂凝胶化。并利用紫外光引 发聚合,“锁定”凝胶网络,形成稳定的有序高级结构。光聚合后,分子凝胶的稳 定时间超过1年;而光聚合前,分子凝胶的稳定时间一般只有几天到几十天。由电 镜和偏光显微镜研究的凝胶形态学表明,凝胶中存在由相互缠结的三维纤维网络构 成的球晶。DSC研究表明,未聚合的分子凝胶中球晶结构的解缔(peak 1)须克服 一个势垒,势能为ΔH = 0.8 kJ·mol~(-1),这主要是一种范德华弱相互作用。而 发生的凝胶-溶胶相转变(peak 2),则说明了自组装纤维中BMDM分子间存在氢键 等次价键相互作用。这种次价键能即为凝胶-溶胶相转变热焓ΔH = 22.3 kJ· mol~(-1)。聚合凝胶只有体积相变而无凝胶-溶胶相转变,且聚合凝胶的体积相变 温度要比光聚合前的凝胶-溶胶相转变温度高出约为110 ~ 120 ℃。研究干聚合凝 胶在丙酮中的溶胀特性发现,其溶胀过程遵循二级溶胀动力学,影响该凝胶溶胀行 为的因素主要是交联程度。  相似文献   

4.
基于分子印迹电聚合膜的双酚A电化学传感器   总被引:3,自引:0,他引:3  
以双酚A为模板分子,邻氨基苯硫酚为单体,采用自组装和电聚合方法,在电极表面制备了对双酚A有选择性的分子印迹聚合物膜.通过循环伏安法研究传感器对双酚A的响应特性.结果表明: 在6.0×10-7~5.5×10-5 mol/L浓度范围内峰电流值与浓度呈良好线性关系(r=0.991);检出限2.0×10-7 mol/L; 相对标准偏差<5%(n=9),达到稳定电流所用时间约2 min.此传感器具有良好的选择性、重现性及稳定性.通过交流阻抗技术和计时电流法表征了电极表面膜的电化学性质.将传感器初步用于实际样品的分析,获得了较满意的结果.  相似文献   

5.
聚合诱导自组装(PISA)是一种新兴的纳米粒子制备技术,它集聚合与组装过程于一体,可在高固含量条件下进行,因此备受青睐.此外,通过改变嵌段聚合度以及固含量等参数,可以精确地控制纳米粒子的形貌,实现从球形胶束到空心囊泡的形貌转变.然而,受限于适用于PISA体系的聚合方法和单体种类,其发展也受到了一定的限制.目前,PISA主要基于可逆加成-断裂链转移聚合(RAFT),其在聚合诱导自组装机理、形貌控制、结构表征等方面的研究成果,对于高分子化学其他领域具有重要的参考价值.然而,由于RAFT聚合诱导自组装(RAFT-PISA)体系中适用的单体往往局限于(甲基)丙烯酸酯类和苯乙烯类,导致RAFT-PISA制备的纳米粒子限于其碳-碳主链的基本结构难以生物降解,因此生物医用前景并不乐观.为了克服以上缺陷,开环聚合诱导自组装(ROPISA)应运而生,主要包括开环易位聚合诱导自组装(ROMPISA)、氨基酸-N-羧基-环内酸酐开环聚合诱导自组装(NCA-PISA)及自由基开环聚合诱导自组装(r ROPISA).由于ROMPISA体系对诸多功能性基团表现出化学惰性,从而为多功能纳米粒子的原位制备提供了新的方...  相似文献   

6.
以磺胺甲噁唑为模板分子,甲基丙烯酸为功能单体,马来松香丙烯酸乙二醇脂为交联剂,采用自组装与电聚合相结合方法,制备了一种对磺胺甲噁唑具有特异性识别位点的分子印迹电化学传感器。通过循环伏安法(CV)、示差脉冲伏安法(DPV)和安培计时法(I-t)表征了该印迹传感膜的电化学性能。结果表明,该传感器具有良好的选择性和灵敏度。在5.0×10-6~2.4×10-3mol·L-1浓度范围内峰电流与浓度呈良好线性关系(R=0.9943);检测限1.67×10-7mol·L-1(S/N=3);达到稳定电流所用时间小于2s。利用此方法成功测定了药物中磺胺甲噁唑的含量。  相似文献   

7.
与共价键聚合物由单体(M1)通过共价键连接不同,超分子聚合物是由单体(M2)通过非共价键连接而成的长链大分子。聚合包括分子聚合和超分子聚合。超分子聚合描述M2通过非共价键自组装形成超分子聚合物的过程,涉及氢键、π-π堆砌型和立体匹配等驱动力以及分子识别、协同性等特征,与M1通过共价键形成聚合物的过程(分子聚合)不同。为了理解超分子聚合物链结构形成机理,本文分析和讨论超分子聚合的三个主要机理:(1)线性链生长;(2)螺旋链生长;(3)拓扑链生长。  相似文献   

8.
以哑铃状2C60聚合体、花生壳状2C60聚合体以及C120富勒烯分子为研究对象,采用AM1半经验量子化学方法,计算了3种C120异构富勒烯分子的几何构型、电子结构、分子能量、疏水常数、极化率与偶极矩;然后,根据计算结果,分析对比了3种C120异构体分子的化学稳定性与物理化学特性.研究结果表明,3种C120分子的形成均为吸热反应,它们的稳定性排序为:C120富勒烯>花生壳状2C60>哑铃状2C60分子.  相似文献   

9.
综述了近年来基于环糊精的原子转移自由基聚合的最新进展.其中,基于环糊精合成化学的原子转移自由基聚合主要表现在:一方面,通过原子转移自由基聚合反应实现环糊精母体的共价键修饰;另一方面,利用该反应参与构筑非共价键的环糊精自组装体系.而通过原子转移自由基聚合反应获得的这些新型环糊精衍生物和自组装体系还可以被进一步应用到有机合成化学、复杂“智能型”超分子自组装体系的构筑、药物输运与控缓释工具、蛋白识别以及手性分离等领域.  相似文献   

10.
聚合物自组装是制备纳米材料的有效途径.自组装纳米材料在药物载体、高性能材料、生物结构模型等领域具有重要的应用价值.近年来,在聚合物分子自组装研究的基础上,研究者们发展了聚合物纳米粒子的自组装研究,并取得了很大进步.聚合物纳米粒子的组装一般可称为超分子反应.以聚肽胶束为组装基元的超分子反应研究得到了很多关注,取得了一系列进展.本文以本课题组的工作为主,总结归纳了近年来在聚肽胶束自组装(超分子反应)研究方面的进展,主要包括超分子聚合、环化和活性生长.文中着重强调了理论模拟在探究胶束超分子反应中的作用.最后,本文展望了该研究领域的发展方向,并指出所面临的机遇和挑战.  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

13.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

14.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

15.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

16.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

17.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

18.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

19.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

20.
A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.  相似文献   

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