共查询到20条相似文献,搜索用时 500 毫秒
1.
Dr. Luca Pescatori Alice Boccia Dr. Flavio Ciesa Dr. Francesca Rossi Dr. Vincenzo Grillo Prof. Arturo Arduini Prof. Andrea Pochini Prof. Robertino Zanoni Dr. Andrea Secchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(36):11089-11099
A series of gold nanoparticles (AuNPs) stabilized by monodentate, bidentate, and tridentate thiolate calix[n]arene ligands 1 – 3 was prepared by using the Brust–Schiffrin two‐phase direct synthesis and characterized with NMR spectroscopy, elemental analysis, transmission electron microscopy (TEM), and X‐ray photoelectron spectroscopy (XPS). The experimental data show that the particular multidentate structure of calix[n]arene derivatives 2 and 3 introduces a control element in the preparation of the gold nanoparticles that allows, in the particular experimental conditions here reported, to obtain very small (≈1 nm) AuNPs. These are the first experimental findings that identify a role of ligand “denticity” in the determination of the nuclearity of nanoparticles. 相似文献
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Kui Wang Dr. Dong‐Sheng Guo Prof. Dr. Yu Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(28):8758-8764
The complexation‐induced critical aggregation concentrations of 1‐pyrenemethylaminium by mono‐p‐sulfonatocalix[n]arenes and bis‐p‐sulfonatocalix[n]arenes (n=4, 5) were systemically measured by fluorescence spectroscopy. In all cases, the complexation‐induced critical aggregation concentration decreases by about 3 times upon addition of p‐sulfonatocalix[n]arenes. However, the optimal molar ratios for the aggregation of 1‐pyrenemethylaminium by mono‐p‐sulfonatocalix[n]arenes and bis‐p‐sulfonatocalix[n]arenes are distinctly different: For mono‐p‐sulfonatocalix[n]arenes, the optimum mixing ratio for the aggregation of 1‐pyrenemethylaminium is 1:4 mono‐p‐sulfonatocalix[n]arenes/1‐pyrenemethylaminium, whereas only 2.5 molecules of 1‐pyrenemethylaminium can be bound by one cavity of bis‐p‐sulfonatocalix[n]arenes. The intermolecular complexation of mono‐p‐sulfonatocalix[n]arenes and bis‐p‐sulfonatocalix[n]arenes with 1‐pyrenemethylaminium led to the formation of two distinctly different nanoarchitectures, which were shown to be nanoscale vesicle and rod aggregates, respectively, by using dynamic laser scattering, TEM, and SEM. This behavior is also different from the fiber‐like aggregates with lengths of several micrometers that were formed by 1‐pyrenemethylaminium itself above its critical aggregation concentration. Furthermore, the obtained nanoaggregates exhibit benign water solubility, self‐labeled fluorescence, and, more importantly, temperature responsiveness. 相似文献
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《化学:亚洲杂志》2017,12(16):2093-2097
Five congeners of [n ]cyclo‐3,6‐phenanthrenylene with 3, 4, 5, 7, and 8 panels were obtained from one‐pot macrocyclization of dibromophenanthrene, and their crystal structures with diverse molecular shapes were revealed by X‐ray crystallography. The compounds, except the four‐panel congener, were highly fluorescent in solution, with quantum yields up to 85 %. The least fluorescent four‐panel congener showed the smallest change in its absorption spectrum from that of monomeric phenanthrene, which provided an interesting structure–activity relationship for fluorescent macrocycles to guide future studies. 相似文献
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Cyclodextrin‐Based Size‐Complementary [3]Rotaxanes: Selective Synthesis and Specific Dissociation 下载免费PDF全文
Yosuke Akae Dr. Yasuhito Koyama Prof. Shigeki Kuwata Prof. Toshikazu Takata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):17132-17136
α‐Cyclodextrin (CD)‐based size‐complementary [3]rotaxanes with alkylene axles were prepared in one‐pot by end‐capping reactions with aryl isocyanates in water. The selective formation of [3]rotaxane with a head‐to‐head regularity was indicated by the X‐ray structural analyses. Thermal degradation of the [3]rotaxanes bearing appropriate end groups proceeded by stepwise dissociation to yield not only the original components but also [2]rotaxanes. From the kinetic profiles of the deslippage, it turned out that the maximum yield of [2]rotaxane was estimated to be 94 %. Thermodynamic studies and NOESY analyses of such rotaxanes revealed that [2]rotaxanes are specially stabilized, and that the dissociation capability of the [3]rotaxanes to the components can be adjusted by controlling the structure of the end groups, direction of the CD groups, and length of the alkylene axle. 相似文献
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Smith BB Hill DE Cropp TA Walsh RD Cartrette D Hipps S Shachter AM Pennington WT Kwochka WR 《The Journal of organic chemistry》2002,67(15):5333-5337
Reaction of the bis-9-BBN adduct of several dienes with 1,3-dibromobenzene via Suzuki coupling leads to a series of [n]metacyclophanes ranging in size from 10 to 17 atom members. In each case, two carbon-carbon bonds are formed in one reaction vessel. However, when the bis-9-BBN adduct of 1,5-hexadiene is coupled with a variety of aryl dihalides, larger [n.n]cyclophanes were formed in preference to the [n]cyclophanes. Four carbon-carbon bonds are formed in this instance. Single-crystal X-ray analyses of these [n.n]cyclophanes reveal interestingly shaped molecules with large cavities. 相似文献
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Eligeti Rajanarendar Paka Venkateshwarlu Saini Ramakrishna Dharavath Nagaraju 《Journal of heterocyclic chemistry》2015,52(4):1007-1013
Synthesis of novel 2‐3‐methyl‐5‐[(E)‐2‐aryl‐1‐ethenyl]‐4‐isoxazolyl‐4,10a‐diaryl‐1,10a‐dihydro‐2H‐benzo[d]pyrazino[2,1‐b][1,3]oxazoles 5 were simply achieved by the reaction of 2‐[3‐methyl‐5‐[(E)‐2‐aryl‐1‐ethenyl]‐4‐isoxazolyl(2‐oxo‐2‐arylethyl)amino]‐1‐aryl‐1‐ethanones 3 with o‐aminophenol 4 in the presence of CAN catalyst. The intermediates, 2‐[3‐methyl‐5‐[(E)‐2‐aryl‐1‐ethenyl]‐4‐isoxazolyl(2‐oxo‐2‐arylethyl)amino]‐1‐aryl‐1‐ethanones 3 , were prepared by the reaction of 4‐amino‐3‐methyl‐5‐styrylisoxazole 1 , with phenacylbromides 2 in ethanol in the presence of K2CO3. The structures of the newly synthesized compounds 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , 3l and 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l have been confirmed by analytical and spectral data. 相似文献
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Philip Warner Bing-Lin Chen Catherine A. Bronski Barbara A. Karcher Robert A. Jacobson 《Tetrahedron letters》1981,22(5):375-376
The synthesis of 3 dithiapaddlanes is described. 相似文献
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Ethyl 1‐ethyl‐7‐methyl‐4‐oxo‐1,4‐dihydro[1,8]naphthyridine‐3‐carboxylate ( 1 ), precursor of nalidixic acid, has been converted in two steps through ([1,8]naphthyridin‐3‐yl)carbonylguanidine derivatives into substituted pyrimido[4,5‐b] and [5,4‐c][1,8]naphthyridines. 相似文献
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The electrochemical properties of a series of 1,4‐dimethoxypillar[m]arene[n]quinones (DMP[m]A[n]Qs) and the interactions between individual quinone units have been investigated on glassy carbon electrode in acetonitrile. All the quinone units showed relative electron uptake behavior except 1,4‐dimethoxypillar[5]quinones (DMP[5]Q). The results have shown that the electrochemical behavior of the DMP[m]A[n]Qs is comparatively different from that of their related linear quinone analogues. The resultant properties were attributed to the close proximity of redox‐active sites as well as the delocalization of electrons on the aromatic rings. Another aspect to be considered responsible for their electronic properties was suggested to be the electrostatic repulsions between adjacent quinone units in these complex structures. Current studies provide a better understanding on the voltammetric behavior of pillararene derivatives with different numbers of quinone units as well as their future scope in certain future electrochemical applications. 相似文献
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Bin Li Bin Wang Xiayang Huang Lu Dai Lei Cui Jian Li Xueshun Jia Chunju Li 《Angewandte Chemie (International ed. in English)》2019,58(12):3885-3889
Herein, two new classes of macrocyclic compounds, terphen[n]arenes (TPns) (n=3–6) and quaterphen[n]arenes (QPns) (n=3–6), were designed and synthesized by a one‐step condensation reaction in relatively high yields. They comprise 2,2′′‐dimethoxy terphenyl and 2,2′′′‐dimethoxy quaterphenyl monomers, respectively, linked by methylene bridges. Given their long and rigid monomers, TPns and QPns have much larger cavities and better self‐assembly properties than classic macrocycles. More interestingly, the cyclic pentamers and hexamers TP5, TP6, QP5, and QP6 formed supramolecular organogels, which were composed of interwoven fibers, nanosheets, or entangled macropore networks formed by multiple face‐to‐face and edge‐to‐face π???π stacking interactions. The xerogel materials effectively captured volatile iodine, not only in aqueous media but also in the gaseous state, and could be recycled multiple times without obvious loss in performance. 相似文献
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Regioselective Synthesis and Characterization of Multinuclear Convex‐Bound Ruthenium‐[n]Cycloparaphenylene (n=5 and 6) Complexes 下载免费PDF全文
Dr. Eiichi Kayahara Dr. Vijay Kumar Patel Audrey Mercier Prof. Dr. E. Peter Kündig Prof. Dr. Shigeru Yamago 《Angewandte Chemie (International ed. in English)》2016,55(1):302-306
Mono‐ and multinuclear complexes of ruthenium and [n]cycloparaphenylene (CPP, n=5 and 6) were synthesized in excellent yields through ligand exchange of the cationic complex [(Cp)Ru(CH3CN)3](PF6) with CPP. In the multinuclear complexes, ruthenium selectively coordinated to alternate paraphenylene units to give bis‐ and tris‐coordinated Ru complexes for [5] and [6]CPPs, respectively. Single‐crystal X‐ray analysis revealed the Ru was coordinated with η6‐hapticity on the convex surface of CPP. 相似文献
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Bin Li Bin Wang Xiayang Huang Lu Dai Lei Cui Jian Li Xueshun Jia Chunju Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(12):3925-3929
Herein, two new classes of macrocyclic compounds, terphen[n]arenes (TPns) (n=3–6) and quaterphen[n]arenes (QPns) (n=3–6), were designed and synthesized by a one‐step condensation reaction in relatively high yields. They comprise 2,2′′‐dimethoxy terphenyl and 2,2′′′‐dimethoxy quaterphenyl monomers, respectively, linked by methylene bridges. Given their long and rigid monomers, TPns and QPns have much larger cavities and better self‐assembly properties than classic macrocycles. More interestingly, the cyclic pentamers and hexamers TP5, TP6, QP5, and QP6 formed supramolecular organogels, which were composed of interwoven fibers, nanosheets, or entangled macropore networks formed by multiple face‐to‐face and edge‐to‐face π???π stacking interactions. The xerogel materials effectively captured volatile iodine, not only in aqueous media but also in the gaseous state, and could be recycled multiple times without obvious loss in performance. 相似文献
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Karen J. Ardila‐Fierro Carsten Bolm Jos G. Hernndez 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(37):13079-13083
A mechanochemical synthesis of one‐dimensional carbon allotrope carbyne model compounds, namely tetraaryl[n]cumulenes (n=3, 5) was realized. Central for the mechanosynthesis of the cumulenic carbon nanostructures were the development of a mechanochemical Favorskii alkynylation‐type reaction and the implementation of a solvent‐free, acid‐free reductive elimination with tin(II) chloride by ball milling. 相似文献
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LIU Si-Min WU Xiao-Jun YAO Jun-Hua WU Cheng-Tai 《有机化学》2003,23(Z1):261-262
Non-covalent attractive forces are commonly employed in biological systems to drive the assembly of highly orga nized supramolecular entities from relatively simple subunits. 相似文献