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51.
Pavel A. Abramov Maxim N. Sokolov Alexander V. Virovets Eugenia V. Peresypkina Vladimir P. Fedin 《Journal of Cluster Science》2007,18(3):597-605
Reaction of [MoOCl5]2− with in situ generated H2Se under hydrothermal conditions (4M HCl, 140 °C) leads to reduction of Mo(V) to Mo(IV) with the formation of a triangular
cluster Mo3(μ3-Se)(μ-O)34+ in high yield. It is present in HCl solutions as aqua chlorocomplex [Mo3(μ3-Se)(μ-O)3(H2O)6Cl3]+ which was isolated and structurally characterized as supramolecular adduct with cucurbit[6]uril (CB[6]), {[Mo3(μ3-Se)(μ-O)3(H2O)6Cl3]2CB[6]}Cl2·15H2O.
Dedicated to Professor Dieter Fenske on the Occasion of his 65th Birthday 相似文献
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Supramolecular Assemblies with Near‐Infrared Emission Mediated in Two Stages by Cucurbituril and Amphiphilic Calixarene for Lysosome‐Targeted Cell Imaging
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Xu‐Man Chen Dr. Yong Chen Qilin Yu Bo‐Han Gu Prof. Yu Liu 《Angewandte Chemie (International ed. in English)》2018,57(38):12519-12523
A two‐stage mediated near‐infrared (NIR) emissive supramolecular assembly for lysosome‐targeted cell imaging is presented. 4,4′‐Anthracene‐9,10‐diylbis(ethene‐2,1‐diyl))bis(1‐ethylpyridin‐1‐ium) bromide (ENDT) was synthesized as an organic dye with weak fluorescence emission at 625 nm. When ENDT complexes with cucurbit[8]uril (CB[8]), this binary supramolecular complex assembles into nanorods with a near‐infrared fluorescence emission (655 nm) and fluorescence enhancement as the first stage. Such supramolecular complexes interact with lower‐rim dodecyl‐modified sulfonatocalix[4]arene (SC4AD) to form nanoparticles for further fluorescence enhancement as the second stage. Furthermore, based on a co‐staining experiment with LysoTracker Blue, such nanoparticles can be applied in NIR lysosome‐targeted cell imaging. 相似文献
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ABSTRACTTwo acyclic CB[n]-type hosts (1 and 2) which possess four 2° or 3° amide arms are reported. Host 2 has four 3° amide arms that exist as a mixture of E- and Z-isomers. 1H NMR was used to qualitatively investigate the binding properties of 1 and 2 which indicates they retain the essential binding features of macrocyclic CB[n] hosts. We measured the Ka values of 1 and 2 toward guests 6–14 by ITC. Neutral hosts 1 and 2 bind less tightly than tetraanionic hosts M1, ACB1, and ACB2. We attribute the lower Ka values to the absence of secondary ion-ion electrostatic interactions for host?guest complexes of 1 and 2. The secondary amide functionality on 1 decreases affinity by the formation of intramolecular NH???O=C H-bonds. Tertiary amide host 2 binds even more weakly than 1 due to backfolding of the amide N-CH3-groups of 2 into its own cavity. 相似文献
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Yiliu Liu Ruochen Fang Xinxin Tan Prof. Zhiqiang Wang Prof. Xi Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(49):15650-15654
We present the construction of long‐chain water‐soluble supramolecular polymers at low monomer concentrations. Naphthalene‐based host‐enhanced π–π interactions, which possess high binding constants, were used as the driving force of supramolecular polymerization. A monomer, DNDAB, with a rigid, bulky 1,4‐diazabicyclo[2.2.2]octane‐1,4‐diium linker was designed. The design of the monomer structure strongly influenced the efficiency of the supramolecular polymerization. The rigid, bulky linker in DNDAB effectively eliminates cyclization, promoting the formation of long‐chain supramolecular polymers at low monomer concentrations. In contrast, a reference monomer containing a flexible linker (DNPDN) only forms oligomers owing to cyclization. 相似文献
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Xuzhuo Sun Bo Li Jin Cao Jing Chen Ning Wang Dongjin Wan Haibo Zhang Xiaohai Zhou 《中国化学》2012,30(4):941-946
A pseudorotaxane of cucurbit[6]uril (CB[6]) with guest molecule N,N′‐hexamethylenebis (pyrazinyl perchlorate) (BPHP) was synthesized and characterized by 1H NMR spectra, IR, single crystal X‐ray diffraction analysis and thermogravimetric analysis. The structure of the pseudorotaxane (CB[6]·BPHP) is stabilized by host‐guest hydrogen bonds. Self‐assembly of the pseudorotaxane produces infinite one‐dimensional and two‐dimensional networks with intermolecular hydrogen bonds. In the molecular packing of the CB[6]·BPHP, ClO4?(H2O)2 water clusters serve as bridges to associate these pseudorotaxanes and form three‐dimensional networked pseudopolyrotaxane. 相似文献
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含有水溶性季铵盐基团的4-正己氨基-1,8-萘酰亚胺化合物在水中与葫芦脲[6]通过疏水及氢键作用形成准轮烷结构,而且体系荧光波长红移了17nm,荧光强度降低32%.研究表明,往准轮烷溶液中加入与葫芦脲[6]具有强结合力的Ba2+离子会使准轮烷结构离解,体系荧光恢复;而再往溶液中加入SO42-,Ba2+以BaSO4沉淀的形式被除去,这时准轮烷又重新生成.核磁氢谱、紫外-可见吸收光谱、荧光光谱和荧光寿命对体系的结合/离解过程的研究表明这种结合/离解过程是可逆的.本体系可以模拟插头/插座的连接和断开动作. 相似文献
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The host–guest interactions between phenazine hydrochloride salt (PheH+) and hemicucurbit[n]uril (n = 6 or 12) (HemiQ[6 or 12]) have been studied by 1H NMR, UV–vis, IR, mass spectrometry (MS) and quantum chemistry. In 1H NMR spectra, the broadening of proton resonances of the hosts suggests the interactions of PheH+ with HemiQs. The quantitative stabilities of the host–guest systems have been obtained by UV–vis titration experiments, that is, the stoichiometric interactions of PheH+ with HemiQ[6] have been observed with an association constant of Ka = (2.5 ± 1.2) × 106 L mol? 1, while the 2:1 ratio complexes of PheH+ with HemiQ[12] are formed with stepwise association constants of K1 = (9.2 ± 2.8) × 104 L mol? 1 and K2 = (6.4 ± 0.9) × 105 L mol? 1, respectively, which induce a total association constant of Ka = 5.9 × 1010 L2 mol? 2. Both the 1:1 and 2:1 complexes have been detected by MS. Quantum chemistry calculations have been used to understand the static structures and thermodynamic stabilities of the supramolecular assemblies. 相似文献
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Da Ma Raymond Glassenberg Soumyadip Ghosh Peter Y. Zavalij 《Supramolecular chemistry》2013,25(5):325-332
The recognition properties of acyclic cucurbit[n]uril (CB[n]) congener 1 towards seven local anaesthetic drugs (2–8) are reported. Job plots constructed from 1H NMR experiments confirm the 1:1 host:guest nature of these complexes, whereas the changes in chemical shift observed upon complex formation (Δδ values) provide information about the geometry of the host–guest complexes. For complexes between host 1 and guests 2–5 and 8, a single geometry was preferred, whereas for guests 6 and 7 a mixture of two diastereomeric complexes was indicated. The K a values for complexes between 1 and 2–8 fall in the range of 103–108 M? 1 as determined by UV–vis and 1H NMR competition experiments. The results further establish that acyclic CB[n]-type receptor 1 is preorganised into the C-shape required for binding and that its aromatic o-xylylene walls endow it with a potency towards aromatic ammonium ions. The K a values reported in this paper constitute a blind data-set used in the SAMPL3 challenge aimed at testing computational methods relevant to protein√ligand systems. The work thus highlights the great potential of CB[n] receptors as model systems to promote synergy between the supramolecular and computational chemistry communities. 相似文献