5,5'-二叔丁基-3-(羧甲基)联苯冠醚和几种带有侧链羧酸基团的套索状醚的合成,以及p K a的测定描述了这些冠醚羧酸的值。另外,已经研究了这些冠醚与尿素的络合。大环联苯冠醚(≥29个环原子)和套索状醚(≥27个环原子)都将尿素溶解在氯仿中。套环醚使尿素络合的数据表明,为了有助于尿素络合,重要的是使羧酸基团靠近大环。当套索状醚的羧酸基团位于适当的位置时,尿素被这些大环配体的21–27%络合,联苯冠醚醚羧酸也是如此。这些结果表明,羧酸侧基可以帮助中性分子的络合。
环状二十七(oxyethyelene)(环-E 27,81冠27)制备线性α羟基苯,ω -羟基二十七(氧乙烯)通过在碱性条件下对甲苯磺酰氯,由制备级凝胶渗透色谱法纯化反应,并通过激光拉曼光谱,广角和小角X射线散射以及差示扫描量热法进行了研究。与线性低聚(氧乙烯)二甲基醚(包括C 1 E 27 C 1)的性质进行了比较。结晶环状低聚物的子单元与其线性对应物的子单元相同,即与高摩尔质量的聚氧乙烯相同。然而,环状低聚物结晶为两倍折叠的环,这是由其较长的间隔和其单节点纵向声模(LAM-1)的频率所证实的。分析了熔化和熔融温度的焓,以提供在低聚(氧化乙烯)层晶体中形成折叠的焓和熵的估计。
The synthesis of largeringcrown compounds with the general structure 3n-crown-n where n is 9 to 20 is reported.
据报道,合成大环冠化合物的一般结构为3n-crown-n,其中n为9至20。
Role of cavities created by azobenzene-modified UiO-66 in bulky ionic liquid for high photoresponsive CO<sub>2</sub> uptake behavior
作者:Meng-Meng Li、Manish Kumar Dinker、Yang Liu、Mingrui Zuo、Lifeng Ding、Xiao-Qin Liu、Lin-Bing Sun
DOI:10.1039/d3ta04786e
日期:——
Photoresponsive porous liquids (PLs) have been reported to capture CO2 which is controlled by light rather than the traditionally employed temperature and pressure. However, the change in CO2 uptake tailored by light is low (≤30%) over the reported photoresponsive PLs. Here, a new photoresponsive type III PL is prepared by dispersing a metal–organic framework (MOF, i.e. Azo-UiO-66 containing pendant
据报道,光响应多孔液体(PL)可以捕获CO 2,这是由光而不是传统采用的温度和压力控制的。然而,与报道的光响应PL相比,光调节的CO 2吸收变化较低(≤30%)。在此,通过将金属有机骨架(MOF,即含有偶氮苯侧链的 Azo-UiO-66)分散在基于聚乙二醇的阳离子大体积离子液体(IL)中,制备了一种新型光响应 III 型 PL。有趣的是,CO 2变化了 78%含有 5% Azo-UiO-66 的 PL 实现了紫外线和可见光照射下的吸收,远高于原始 Azo-UiO-66 (38%) 和纯 IL (1%) 以及所有报道的那些光响应 PL(≤30%)。我们证明,除了 Azo-UiO-66 中的内在空穴之外,外在空穴是由 IL 与悬垂偶氮苯围绕框架堆积而产生的。在紫外光照射下,偶氮苯基团的弯曲掩盖了活性位点,并导致IL围绕MOF紧密堆积,从而消除了外在空穴并降低了CO 2吸附。这是首次报道PL
Permanent cavities in ionic liquids created by metal–organic polyhedra
As an emerging type of material, porous liquids combine the fluidity of liquids with the permanent porosity of porous solids, which makes them promising for various applications. Despite several significant attempts earlier, the porous liquid system still requires the novel entries of porous hosts and bulky liquids. Here, we report a new porous liquid system based on the coalition of metal–organic
作为一种新兴的材料,多孔液体结合了液体的流动性和多孔固体的永久孔隙率,这使得它们在各种应用中都有希望。尽管早些时候进行了几次重大尝试,但多孔液体系统仍然需要多孔主体和大体积液体的新入口。在这里,我们报告了一种新的多孔液体系统,该系统基于金属-有机多面体和精心设计的大体积离子液体的结合。作为概念验证,典型的金属有机多面体 Pd 12 L 24其中 L 代表配体,被用作多孔主体。此外,一种分子尺寸大于Pd 12 L 24孔径的聚乙二醇连接的双咪唑基大体积离子液体被设计为溶剂,产生 II 型多孔离子液体。与纯离子液体相比,这些具有永久空腔、良好的热稳定性和长期耐用性的液体材料捕获了较高的 CO 2 。此外,发现它们不仅将CO 2从N 2和CH 4分子中分离出来,而且还作为支撑的多孔液体膜。我们期望本策略可用于构建具有特定功能的其他多孔液体,以用于其他应用。
Neurotransmitter-Responsive Nanosensors for <i>T</i><sub>2</sub>-Weighted Magnetic Resonance Imaging
Neurotransmitter-sensitive contrast agents for magnetic resonance imaging (MRI) have recently been used for mapping signaling dynamics in live animal brains, but paramagnetic sensors for T-1-weighted MRI are usually effective only at micromolar concentrations that themselves perturb neurochemistry. Here we present an alternative molecular architecture for detecting neurotransmitters, using superparamagnetic iron oxide nanoparticles conjugated to tethered neurotransmitter analogs and engineered neurotransmitter binding proteins. Interactions between the nanoparticle conjugates result in clustering that is reversibly disrupted in the presence of neurotransmitter analytes, thus altering T-2-weighted MRI signals. We demonstrate this principle using tethered dopamine and serotonin analogs, together with proteins selected for their ability to competitively bind either the analogs or the neurotransmitters themselves. Corresponding sensors for dopamine and serotonin exhibit target-selective relaxivity changes of up to 20%, while also operating below endogenous neurotransmitter concentrations. Semisynthetic magnetic particle sensors thus represent a promising path for minimally perturbative studies of neurochemical analytes.
AARTS, VERONIKA M. L. J.;GROOTENHUIS, PETER D. J.;REINHOUDT, DAVID N.;CZE+, REC. TRAV. CHIM. PAYS-BAS, 107,(1988) N 2, 94-103
作者:AARTS, VERONIKA M. L. J.、GROOTENHUIS, PETER D. J.、REINHOUDT, DAVID N.、CZE+