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101.
Prof. Hong Wu Chunyong Tian Dr. Yufei Zhang Dr. Jiafu Shi Chen Yang Prof. Songping Zhang Prof. Zhongyi Jiang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10185-10190
A diffusion‐limited assembly approach was explored to fabricate symmetrical [Cu(Succinate)]n microclusters with a different shape and size for the first time. The molecular structure of succinate and its coordination reaction capability towards copper(II) ions governed the one‐dimensional growth of the nanofibers and the concomitant formation of the microclusters. In detail, a symmetrical concentration gradient was formed around the endpoints of the nanofibers caused by the diffusion‐limited process at high reactant concentrations. The concentration gradient forced the nanofibers to grow divergently and further aggregate into open microcluster structure. The shape and size of the microclusters could be tuned by altering the concentration of the reactants. Particularly, mask‐like double‐hole symmetrical microclusters (MDHSMs) were obtained when the concentration of both reactants was as high as 140 mM . The resultant MDHSMs showed high selectivity in adsorption of dyes and proteins, and may find potential applications in water treatment, bioseparation, and immobilization of biomacromolecules. 相似文献
102.
Reduced Graphene Oxide‐Supported TiO2 Fiber Bundles with Mesostructures as Anode Materials for Lithium‐Ion Batteries 下载免费PDF全文
Mengmeng Zhen Xiaohe Zhu Xiao Zhang Prof. Zhen Zhou Prof. Lu Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14454-14459
Although the synthesis of mesoporous materials is well established, the preparation of TiO2 fiber bundles with mesostructures, highly crystalline walls, and good thermal stability on the RGO nanosheets remains a challenge. Herein, a low‐cost and environmentally friendly hydrothermal route for the synthesis of RGO nanosheet‐supported anatase TiO2 fiber bundles with dense mesostructures is used. These mesostructured TiO2‐RGO materials are used for investigation of Li‐ion insertion properties, which show a reversible capacity of 235 mA h g?1 at 200 mA g?1 and 150 mA h g?1 at 1000 mA g?1 after 1000 cycles. The higher specific surface area of the new mesostructures and high conductive substrate (RGO nanosheets) result in excellent lithium storage performance, high‐rate performance, and strong cycling stability of the TiO2‐RGO composites. 相似文献
103.
Asymmetric Ruthenium‐Catalyzed Hydrogenation of 2,6‐Disubstituted 1,5‐Naphthyridines: Access to Chiral 1,5‐Diaza‐cis‐Decalins 下载免费PDF全文
Jianwei Zhang Fei Chen Yan‐Mei He Prof. Dr. Qing‐Hua Fan 《Angewandte Chemie (International ed. in English)》2015,54(15):4622-4625
The first asymmetric hydrogenation (AH) of 2,6‐disubstituted and 2,3,6‐trisubstituted 1,5‐naphthyridines, catalyzed by chiral cationic ruthenium diamine complexes, has been developed. A wide range of 1,5‐naphthyridine derivatives were efficiently hydrogenated to give 1,2,3,4‐tetrahydro‐1,5‐naphthyridines with up to 99 % ee and full conversions. This facile and green protocol is applicable to the scaled‐up synthesis of optically pure 1,5‐diaza‐cis‐decalins, which have been used as rigid chelating diamine ligands for asymmetric synthesis. 相似文献
104.
Enantioselective Construction of Vicinal Tetrasubstituted Stereocenters by the Mannich Reaction of Silyl Ketene Imines with Isatin‐Derived Ketimines 下载免费PDF全文
Jiannan Zhao Bing Fang Weiwei Luo Xiaoyu Hao Prof. Dr. Xiaohua Liu Dr. Lili Lin Prof. Dr. Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2015,54(1):241-244
A highly enantioselective Mannich reaction of silyl ketene imines with isatin‐derived ketimines has been realized by using a chiral N,N′‐dioxide/ZnII catalyst. A variety of β‐amino nitriles containing congested vicinal tetrasubstituted stereocenters were obtained with excellent outcomes (up to 98 % yield, >19:1 d.r. and 99 % ee). Based on the experimental investigations, a possible transition state has been proposed to explain the origin of the asymmetric induction. 相似文献
105.
Alkane Activation Initiated by Hydride Transfer: Co‐conversion of Propane and Methanol over H‐ZSM‐5 Zeolite 下载免费PDF全文
Si‐Min Yu Dr. Jian‐Feng Wu Chong Liu Dr. Wei Liu Prof. Dr. Shi Bai Dr. Jun Huang Prof. Dr. Wei Wang 《Angewandte Chemie (International ed. in English)》2015,54(25):7363-7366
Co‐conversion of alkane with another reactant over zeolite catalysts has emerged as a new approach to the long‐standing challenge of alkane transformation. With the aid of solid‐state NMR spectroscopy and GC‐MS analysis, it was found that the co‐conversion of propane and methanol can be readily initiated by hydride transfer at temperatures of ≥449 K over the acidic zeolite H‐ZSM‐5. The formation of 13C‐labeled methane and singly 13C‐labeled n‐butanes in selective labeling experiments provided the first evidence for the initial hydride transfer from propane to surface methoxy intermediates. The results not only provide new insight into carbocation chemistry of solid acids, but also shed light on the low‐temperature transformation of alkanes for industrial applications. 相似文献
106.
Development of Chiral Spiro P‐N‐S Ligands for Iridium‐Catalyzed Asymmetric Hydrogenation of β‐Alkyl‐β‐Ketoesters 下载免费PDF全文
Deng‐Hui Bao Hui‐Ling Wu Chao‐Lun Liu Prof. Jian‐Hua Xie Prof. Qi‐Lin Zhou 《Angewandte Chemie (International ed. in English)》2015,54(30):8791-8794
The chiral tridentate spiro P‐N‐S ligands (SpiroSAP) were developed, and their iridium complexes were prepared. Introduction of a 1,3‐dithiane moiety into the ligand resulted in a highly efficient chiral iridium catalyst for asymmetric hydrogenation of β‐alkyl‐β‐ketoesters, producing chiral β‐alkyl‐β‐hydroxyesters with excellent enantioselectivities (95–99.9 % ee) and turnover numbers of up to 355 000. 相似文献
107.
Photocontrolled Reversible Conversion of Nanotube and Nanoparticle Mediated by β‐Cyclodextrin Dimers 下载免费PDF全文
He‐Lue Sun Dr. Yong Chen Jin Zhao Prof. Dr. Yu Liu 《Angewandte Chemie (International ed. in English)》2015,54(32):9376-9380
A photochemically interconvertible supramolecular nanotube–nanoparticle system was constructed through secondary assembling of self‐aggregates of amphiphilic porphyrin derivatives mediated by trans‐ and cis‐azobenzene‐bridged bis(permethyl‐β‐cyclodextrin). Significantly, these nanotubes and nanoparticles were able to interconvert upon irradiation at different wavelengths, and this photocontrolled morphological conversion is reversible and recyclable for tens of times, which will provide a feasible and convenient way to construct the ordered nanostructure with various morphologies that can be smartly controlled by the environmentally benign external stimulus. 相似文献
108.
Asymmetric Ring‐Opening of Cyclopropyl Ketones with Thiol,Alcohol, and Carboxylic Acid Nucleophiles Catalyzed by a Chiral N,N′‐Dioxide–Scandium(III) Complex 下载免费PDF全文
Yong Xia Dr. Lili Lin Fenzhen Chang Xuan Fu Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2015,54(46):13748-13752
A highly efficient asymmetric ring‐opening reaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N′‐dioxide–scandium(III) complex as catalyst. The corresponding sulfides, ethers, and esters were obtained in up to 99 % yield and 95 % ee. This is also the first example of one catalytic system working for the ring‐opening reaction of donor–acceptor cyclopropanes with three different nucleophiles, let alone in an asymmetric version. 相似文献
109.
Dirigent Proteins from Cotton (Gossypium sp.) for the Atropselective Synthesis of Gossypol 下载免费PDF全文
Isabelle Effenberger Dr. Bin Zhang Dr. Ling Li Qiang Wang Prof. Dr. Yuxiu Liu Iris Klaiber Dr. Jens Pfannstiel Prof. Dr. Qingmin Wang Prof. Dr. Andreas Schaller 《Angewandte Chemie (International ed. in English)》2015,54(49):14660-14663
Gossypol is a defense compound in cotton plants for protection against pests and pathogens. Gossypol biosynthesis involves the oxidative coupling of hemigossypol and results in two atropisomers owing to hindered rotation around the central binaphthyl bond. (+)‐Gossypol predominates in vivo, thus suggesting stereochemically controlled biosynthesis. The aim was to identify the factors mediating (+)‐gossypol formation in cotton and to investigate their potential for asymmetric biaryl synthesis. A dirigent protein from Gossypium hirsutum (GhDIR4) was found to confer atropselectivity to the coupling of hemigossypol in presence of laccase and O2 as an oxidizing agent. (+)‐Gossypol was obtained in greater than 80 % enantiomeric excess compared to racemic gossypol in the absence of GhDIR4. The identification of GhDIR4 highlights a broader role for DIRs in plant secondary metabolism and may eventually lead to the development of DIRs as tools for the synthesis of axially chiral binaphthyls. 相似文献
110.
Asymmetric Dearomatization of β‐Naphthols through a Bifunctional‐Thiourea‐Catalyzed Michael Reaction 下载免费PDF全文
Shou‐Guo Wang Xi‐Jia Liu Qun‐Chao Zhao Dr. Chao Zheng Shao‐Bo Wang Prof. Dr. Shu‐Li You 《Angewandte Chemie (International ed. in English)》2015,54(49):14929-14932
An intermolecular asymmetric dearomatization reaction of β‐naphthols with nitroethylene through a chiral‐thiourea‐catalyzed Michael reaction is described. Enantioenriched functionalized β‐naphthalenones with an all‐carbon quaternary stereogenic center could thus be easily constructed from simple naphthol derivatives in good yields and excellent enantioselectivity (up to 79 % yield, 98 % ee). 相似文献