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991.
Sulfur‐Annulated Hexa‐peri‐hexabenzocoronene Decorated with Phenylthio Groups at the Periphery 下载免费PDF全文
Dr. Yuan‐Zhi Tan Dr. Silvio Osella Yi Liu Bo Yang Prof. Dr. David Beljonne Prof. Dr. Xinliang Feng Prof. Dr. Klaus Müllen 《Angewandte Chemie (International ed. in English)》2015,54(10):2927-2931
The chemical nature of the edge periphery essentially determines the physical properties of graphene. As a molecular‐level model system, large polycyclic aromatic hydrocarbons, that is, so‐called nanographenes, can be chemically modified through either edge functionalization or doping with heteroatoms. Although the synthetic methods for edge substitution are well‐developed, incorporation with heteroatoms by the bay annulation of large PAHs remains an enormous challenge. In this study, we present a feasible peripheral sulfur annulation of hexa‐peri‐hexabenzocoronene (HBC) by thiolation of perchlorinated HBC. The tri‐sulfur‐annulated HBC and di‐sulfur‐annulated HBC decorated with phenylthio groups were obtained and characterized by X‐ray diffraction, revealing their distinct sulfur‐annulated peripheral structure. Associated with theoretical calculations, we propose that the regioselective sulfur annulation results from the minimization of strain in the aromatic backbone. We further demonstrate the structure‐correlated property modulation by sulfur annulation, manifested by a decrease in band gap and tunable redox activity. 相似文献
992.
Dr. Junhe Ma Qing Cao Dr. Sarah M. McLeod Keith Ferguson Ning Gao Prof. Alexander L. Breeze Dr. Jun Hu 《Angewandte Chemie (International ed. in English)》2015,54(16):4764-4767
An NMR‐based approach marries the two traditional screening technologies (phenotypic and target‐based screening) to find compounds inhibiting a specific enzymatic reaction in bacterial cells. Building on a previous study in which it was demonstrated that hydrolytic decomposition of meropenem in living Escherichia coli cells carrying New Delhi metallo‐β‐lactamase subclass 1 (NDM‐1) can be monitored in real time by NMR spectroscopy, we designed a cell‐based NMR screening platform. A strong NDM‐1 inhibitor was identified with cellular IC50 of 0.51 μM , which is over 300‐fold more potent than captopril, a known NDM‐1 inhibitor. This new screening approach has great potential to be applied to targets in other cell types, such as mammalian cells, and to targets that are only stable or functionally competent in the cellular environment. 相似文献
993.
Light‐Directing Omnidirectional Circularly Polarized Reflection from Liquid‐Crystal Droplets 下载免费PDF全文
Dr. Jing Fan Dr. Yannian Li Dr. Hari Krishna Bisoyi Prof. Rafael S. Zola Prof. Deng‐ke Yang Dr. Timothy J. Bunning Prof. David A. Weitz Prof. Quan Li 《Angewandte Chemie (International ed. in English)》2015,54(7):2160-2164
Constructing and tuning self‐organized three‐dimensional (3D) superstructures with tailored functionality is crucial in the nanofabrication of smart molecular devices. Herein we fabricate a self‐organized, phototunable 3D photonic superstructure from monodisperse droplets of one‐dimensional cholesteric liquid crystal (CLC) containing a photosensitive chiral molecular switch with high helical twisting power. The droplets are obtained by a glass capillary microfluidic technique by dispersing into PVA solution that facilitates planar anchoring of the liquid‐crystal molecules at the droplet surface, as confirmed by the observation of normal incidence selective circular polarized reflection in all directions from the core of individual droplet. Photoirradiation of the droplets furnishes dynamic reflection colors without thermal relaxation, whose wavelength can be tuned reversibly by variation of the irradiation time. The results provided clear evidence on the phototunable reflection in all directions. 相似文献
994.
Dr. Xin Fang Ying Tong Di Yu Zhang Dr. Zhi Ping Xu Prof. Yang Lu Qian Qian Chen Prof. Qi Tai Zheng Prof. Dr. Xiao Jiang Hao 《Angewandte Chemie (International ed. in English)》2015,54(19):5592-5595
Perforalactone A ( 1 ), a new 20S quassinoid with a unique cagelike 2,4‐dioxaadamantane ring system and a migrated side chain, was isolated from the plant Harrisonia perforata together with two biosynthetically related new quassinoids. The structures of these natural products were elucidated by NMR spectroscopy, X‐ray diffraction analysis, computational modeling, and the CD excitation chirality method. The compounds exhibited notable biological properties, including insecticidal activity against Aphis medicaginis Koch and antagonist activity at the nicotinic acetylcholine receptor of Drosophila melanogaster. The structural features of these compounds may be related to their promising biological characteristics. Their biosynthesis and an alternative origin of quassinoid‐type natural products are also discussed. 相似文献
995.
Reversible Modulation of Surface Plasmons in Gold Nanoparticles Enabled by Surface Redox Chemistry 下载免费PDF全文
Dr. Zheng Li Dr. Jonathan J. Foley IV Dr. Sheng Peng Dr. Cheng‐Jun Sun Dr. Yang Ren Dr. Gary P. Wiederrecht Dr. Stephen K. Gray Dr. Yugang Sun 《Angewandte Chemie (International ed. in English)》2015,54(31):8948-8951
Switchable surface redox chemistry is demonstrated in gold@iron/iron oxide core–shell nanoparticles with ambient oxidation and plasmon‐mediated reduction to modulate the oxidation state of shell layers. The iron shell can be oxidized to iron oxide through ambient oxidation, leading to an enhancement and red‐shift of the gold surface plasmon resonance (SPR). This enhanced gold SPR can drive reduction of the iron oxide shell under broadband illumination to reversibly blue‐shift and significantly dampen gold SPR absorption. The observed phenomena provide a unique mechanism for controlling the plasmonic properties and surface chemistry of small metal nanoparticles. 相似文献
996.
Inside Back Cover: Intermolecular Enantioselective Dearomatization Reaction of β‐Naphthol Using meso‐Aziridine: A Bifunctional In Situ Generated Magnesium Catalyst (Angew. Chem. Int. Ed. 7/2015) 下载免费PDF全文
997.
Highly Efficient Solid‐Phase Labeling of Saccharides within Boronic Acid Functionalized Mesoporous Silica Nanoparticles 下载免费PDF全文
Xianghua Pan Yang Chen Peixuan Zhao Daojin Li Dr. Zhen Liu 《Angewandte Chemie (International ed. in English)》2015,54(21):6173-6176
Labeling is critical for the detection, quantitation, and structural identification of saccharides. However, conventional liquid‐phase labeling suffers from apparent disadvantages, such as time‐consuming, the presence of excessive labeling reagent, and high applicable saccharide concentration. A solid‐phase approach is presented for highly efficient labeling of saccharides, using boronic acid functionalized mesoporous silica nanoparticles (MSNs) as a selective extraction sorbent and nanoscale reactor. The solid‐phase labeling approach exhibited several significant advantages, including: much faster reaction speed (taking only 2 min), high product purity, and much lower applicable saccharide concentration (four orders of magnitude lower than that of liquid‐phase labeling). Thus, this labeling approach opens up new avenues to the facile and efficient labeling of saccharides. 相似文献
998.
Rhodium(III)‐Catalyzed [3+2]/[5+2] Annulation of 4‐Aryl 1,2,3‐Triazoles with Internal Alkynes through Dual C(sp2)H Functionalization 下载免费PDF全文
Yuan Yang Ming‐Bo Zhou Xuan‐Hui Ouyang Rui Pi Dr. Ren‐Jie Song Prof. Dr. Jin‐Heng Li 《Angewandte Chemie (International ed. in English)》2015,54(22):6595-6599
A rhodium(III)‐catalyzed [3+2]/[5+2] annulation of 4‐aryl 1‐tosyl‐1,2,3‐triazoles with internal alkynes is presented. This transformation provides straightforward access to indeno[1,7‐cd]azepine architectures through a sequence involving the formation of a rhodium(III) azavinyl carbene, dual C(sp2)? H functionalization, and [3+2]/[5+2] annulation. 相似文献
999.
Spontaneous Reconstitution of Functional Transmembrane Proteins During Bioorthogonal Phospholipid Membrane Synthesis 下载免费PDF全文
Christian M. Cole Dr. Roberto J. Brea Young Hun Kim Michael D. Hardy Prof. Jerry Yang Prof. Neal K. Devaraj 《Angewandte Chemie (International ed. in English)》2015,54(43):12738-12742
Transmembrane proteins are critical for signaling, transport, and metabolism, yet their reconstitution in synthetic membranes is often challenging. Non‐enzymatic and chemoselective methods to generate phospholipid membranes in situ would be powerful tools for the incorporation of membrane proteins. Herein, the spontaneous reconstitution of functional integral membrane proteins during the de novo synthesis of biomimetic phospholipid bilayers is described. The approach takes advantage of bioorthogonal coupling reactions to generate proteoliposomes from micelle‐solubilized proteins. This method was successfully used to reconstitute three different transmembrane proteins into synthetic membranes. This is the first example of the use of non‐enzymatic chemical synthesis of phospholipids to prepare proteoliposomes. 相似文献
1000.
Chun‐Hua Yang Yu‐Shi Zhang Wen‐Wen Fan Dr. Gong‐Qing Liu Prof. Dr. Yue‐Ming Li 《Angewandte Chemie (International ed. in English)》2015,54(43):12636-12639
A direct and catalyst‐free method for the intramolecular aminoboration of unfunctionalized olefins is reported. In the presence of BCl3 (1 equiv) as the sole boron source, intramolecular aminoboration of sulfonamide derivatives of 4‐penten‐1‐amines, 5‐hexen‐1‐amines, and 2‐allylanilines proceeded readily without the use of any catalyst. The boronic acids obtained after hydrolysis could be converted into the corresponding pinacol borates in a straightforward manner by treatment with pinacol under anhydrous conditions. 相似文献