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81.
Neslihan Saki Burcak Icli Orkun Cevheroglu Engin U. Akkaya 《Journal of inclusion phenomena and macrocyclic chemistry》2006,55(3-4):219-222
In an attempted synthesis of peripherally pyridine-substituted cucurbituril, an unexpected cyclized product was obtained. A careful NMR analysis followed by mass spectrometry and preliminary crystallographic analyses, helped us in resolving the structure. The structure has two quaternized pyridine functionalities and a groove suitable as a potential receptor site. In addition, just like the parent glycoluril structure, two remaining urea-derived nitrogens can be alkylated by alkyl halides. Thus, we believe this high yielding reaction may become an entry point to a new class of anion receptors. 相似文献
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Samsonenko D. G. Sokolov M. N. Gerasko O. A. Virovets A. V. Lipkowski J. Fenske D. Fedin V. P. 《Russian Chemical Bulletin》2003,52(10):2132-2139
Slow evaporation of solutions of samarium nitrate and thorium chloride in hydrochloric acid containing the macrocyclic cavitand cucurbituril (C36H36N24O12) afforded crystals of the [{Sm(H2O)5(NO3)}2(C36H36N24O12)](NO3)4·6.5H2O and [{Th(H2O)5Cl}2(C36H36N24O12)]Cl6·13H2O complexes, respectively. The [Sm(C36H36N24O12)(H2O)5(SO4)][Sm(H2O)5(SO4)2]·17H2O complex was generated upon heating (130 °C) of a mixture of samarium sulfate, cucurbituril, and water in a sealed tube. X-ray diffraction analysis demonstrated that the metal atoms in these complexes are bound to the portal oxygen atoms of the cucurbituril molecules. In addition, the portal oxygen atoms of cucurbituril are linked to the coordinated H2O molecules via hydrogen bonds. 相似文献
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Gerasko O. A. Virovets A. V. Sokolov M. N. Dybtsev D. N. Gerasimenko A. V. Fenske D. Fedin V. P. 《Russian Chemical Bulletin》2002,51(10):1800-1805
The supramolecular compounds {[W3Se4Cl3(H2O)6]2[PyHC36H36N24O12]}Cl3·18H2O (1) and {[Cl3SnMo3Se4Cl3(H2O)6][Cl3SnMo3Se4Cl2(H2O)7](C36H36N24O12)}Cl·26H2O (2) were isolated from solutions of the selenium-containing tungsten and molybdenum clusters [W3Se4(H2O)9]4+ and [Cl3SnMo3Se4(H2O)9]3+, respectively, and organic cavitand cucurbituril. X-ray diffraction analysis demonstrated that the macrocylcic cucurbituril molecule is coordinated on both sides by the cluster cations through the formation of complementary hydrogen bonds. Compound 1 has a chain structure stabilized by Se...Se interactions between the adjacent cluster cores. In compound 2, the bridging 2-selenium atoms of the cluster fragment Mo3Se4 are coordinated to the tin atom of the SnCl3
– ligand, thus losing the ability to be involved in Se...Se interactions. 相似文献
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甘脲是羟基葫芦[6]脲(HOCB6)的前体, 本文设计了一种在酸性条件下均匀涂渍固定液的新方法, 首次将甘脲和羟基葫芦[6]脲用作气相色谱固定相. 将甘脲和HOCB6填装成气相色谱填充柱后, 以烷烃、卤代烃、芳香烃、醇、酮、酯、酸、胺等物质为探针, 用复杂样品花露水对它们的色谱分离性能进行了比较研究. 结果表明, 甘脲和HOCB6 都是良好的气相色谱固定相, 热稳定性高, 柱性能稳定. 两种固定相对以上溶质探针都有较好的分离能力, HOCB6固定相(PSP)与甘脲固定相(GSP)相比较, 总体上具有更好的分离选择性, 对难分离的芳香族位置异构体(如二甲苯、甲基苯胺)具有良好的分离能力, 显示出较高的立体选择性, 对花露水中的高沸点组分有较好的分离效果. 上述研究也表明, 由于溶质在载气中传质比葫芦脲内腔快得多, 全包结尽管有利于提高分离选择性, 但展宽后的柱效不理想; 适当的高柱温既保留了部分包结作用, 同时存在端口协同作用, 能兼顾高选择性和高柱效. 相似文献
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Natali Dubel Susanne Liese Franziska Scherz Oliver Seitz 《Angewandte Chemie (International ed. in English)》2019,58(3):907-911
Multivalency can facilitate complex formation when monovalent receptor–ligand interactions are weak. However, enhanced binding of two multivalent binding partners should be avoidable, for example when bivalent receptors ought to utilize multimolecular interactions to cross‐link binding partners. We herein report the first systematic study to assess the criteria deciding whether a bivalent system engages in bivalency‐enhanced interactions or cross‐linking. We used DNA‐instructed self‐assembly to arrange the cucurbit[7]uril–adamantane host–guest system in 70–360 Å distance. Measurements and statistical mechanics analyses revealed that the affinity gain is controlled by 1) the distance between recognition modules, 2) the scaffold flexibility, and, importantly, 3) the strength of the monovalent interaction. We show that the bivalency effect can extend beyond 150 Å and discuss how, on the contrary, weak monovalent interactions reduce the concentration threshold for cross‐linking. The findings are of interest for inhibitor design. 相似文献
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Hyunsik Choi Byung Woo Hwang Kyeng Min Park Ki Su Kim Sei Kwang Hahn 《Particle & Particle Systems Characterization》2020,37(1):1900418
Recently, micro/nanomotor systems have been widely investigated for biomedical applications especially for the active transport and delivery of specific drugs. However, there are few stimuli-responsive micro/nanomotor systems to enhance the drug delivery efficiency and reduce side effects by the spatiotemporal controllability. Here, a degradable nanomotor is first fabricated for targeted drug delivery using a platinum (Pt)-deposited complex of calcium carbonate and cuccurbit[6]uril-conjugated hyaluronate (Pt/CaCO3@HA-CB[6]). The nanomotors could efficiently deliver model drugs to the cells in reactive oxygen species (ROS) abundant environments such as the tumor site. After reaching the tumor site around pH 6.5, Pt/CaCO3@HA-CB[6] nanomotors (≈1 µm) are pH-responsively disintegrated by the dissociation of CaCO3 and the encapsulated HA-CB[6] (≈300 nm) are released for cancer cell uptake. The released HA conjugate are finally uptaken into cancer cells via HA receptor-mediated endocytosis. Moreover, model drugs are modularly loaded into the nanomotors via the host–guest chemistry of CB[6] for stable delivery to cancer cells. Taken together, Pt/CaCO3@HA-CB[6] nanomotors systems could be successfully harnessed for active drug delivery to cancer cells. 相似文献