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841.
Copper‐Catalyzed NH Insertion and Oxidative Aromatization Cascade: Facile Synthesis of 2‐Arylaminophenols 下载免费PDF全文
Dong Ding Xiaobing Lv Dr. Jian Li Guangyang Xu Dr. Bing Ma Prof. Dr. Jiangtao Sun 《化学:亚洲杂志》2014,9(6):1539-1542
A copper‐catalyzed cascade reaction of N‐H insertion and oxidative aromatization has been developed. 2‐Arylaminophenols have been prepared in moderate to high yields from the diazo substrates. Moreover, this newly established methodology allows efficient access to natural 1‐oxygenated carbazole alkaloids, such as glycozolicine and murrayafoline A. 相似文献
842.
Self‐Assembly of Five 8‐Hydroxyquinolinate‐Based Complexes: Tunable Core,Supramolecular Structure,and Photoluminescence Properties 下载免费PDF全文
Prof. Dr. Guozan Yuan Weilong Shan Xuelong Qiao Li Ma Prof. Dr. Yanping Huo 《化学:亚洲杂志》2014,9(7):1913-1921
Five new ZnII complexes, namely [Zn3(L)6] ( 1 ), [Zn2(Cl)2(L)2(py)2] ( 2 ), [Zn2(Br)2(L)2(py)2] ( 3 ), [Zn(L)2(py)] ( 4 ), and [Zn2(OAc)2(L)2(py)2] ( 5 ), were prepared by the solvothermal reaction of ZnX2 (X?=Cl?, Br?, F?, and OAc?) salts with a 8‐hydroxyquinolinate ligand (HL) that contained a trifluorophenyl group. All of the complexes were characterized by elemental analysis, IR spectroscopy, and powder and single‐crystal X‐ray crystallography. The building blocks exhibited unprecedented structural diversification and their self‐assembly afforded one mononuclear, three binuclear, and one trinuclear ZnII structures in response to different anions and solvent systems. Complexes 1 – 5 featured four types of supramolecular network controlled by non‐covalent interactions, such as π???π‐stacking, C? H???π, hydrogen‐bonding, and halogen‐related interactions. Investigation of their photoluminescence properties exhibited disparate emission wavelengths, lifetimes, and quantum yields in the solid state. 相似文献
843.
Guang‐Ming Liang Jing Shang Kun‐Guo Yang Kai Ma Qing‐Ling Ni 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(4):379-383
The title compounds, bis{μ‐N‐[(diphenylphosphanyl)methyl]pyridin‐4‐amine‐κ2N1:P}disilver bis(perchlorate) acetonitrile monosolvate, [Ag2(C18H17N2P)2](ClO4)2·CH3CN, (1), and bis{μ‐N‐[(diphenylphosphanyl)methyl]pyridin‐4‐amine‐κ2N1:P}bis[(nitrato‐κ2O,O)silver], [Ag2(C18H17N2P)2(NO3)2], (2), each contain disilver macrocyclic [Ag2(C18H17N2P)2]2+ cations lying about inversion centres. The cations are constructed by two N‐[(diphenylphosphanyl)methyl]pyridin‐4‐amine (DPP) ligands linking two Ag+ cations in a head‐to‐tail fashion. In (1), the unique Ag+ cation has a near‐linear coordination geometry consisting of one pyridine N atom and one P atom from two different DPP ligands. Two ClO4− anions doubly bridge two metallomacrocycles through Ag...O and N—H...O weak interactions to form a chain extending in the c direction. The half‐occupancy acetonitrile molecule lies with its methyl C atom on a twofold axis and makes a weak N...Ag contact. In (2), there are two independent [Ag(C18H17N2P)]+ cations. The nitrate anions weakly chelate to each Ag+ cation, leading to each Ag+ cation having a distorted tetrahedral coordination geometry consisting of one pyridine N atom and one P atom from two different DPP ligands, and two chelating nitrate O atoms. Each dinuclear [Ag2(C18H17N2P)2(NO3)2] molecule acts as a four‐node to bridge four adjacent equivalent molecules through N—H...O interactions, forming a two‐dimensional sheet parallel to the bc plane. Each sheet contains dinuclear molecules involving just Ag1 or Ag2 and these two types of sheet are stacked in an alternating fashion. The sheets containing Ag1 all lie near x = , , etc, while those containing Ag2 all lie near x = 0, 1, 2 etc. Thus, the two independent sheets are arranged in an alternating sequence at x = 0, , 1, etc. These two different supramolecular structures result from the different geometric conformations of the templating anions which direct the self‐assembly of the cations and anions. 相似文献
844.
Peter C. Roozemond Martin van Drongelen Zhe Ma Anne B. Spoelstra Daniel Hermida‐Merino Gerrit W. M. Peters 《Macromolecular rapid communications》2015,36(4):385-390
Flow‐induced structure formation is investigated with in situ wide‐angle X‐ray diffraction with high acquisition rate (30 Hz) using isotactic polypropylene in a piston‐driven slit flow with high wall shear rates (up to ≈900 s−1). We focus on crystallization within the shear layers that form in the high shear rate regions near the walls. Remarkably, the kinetics of the crystallization process show no dependence on either flow rate or flow time; the crystallization progresses identically regardless. Stronger or longer flows only increase the thickness of the layers. A conceptual model is proposed to explain the phenomenon. Above a certain threshold, the number of shish‐kebabs formed affects the rheology such that further structure formation is halted. The critical amount is reached already within 0.1 s under the current flow conditions. The change in rheology is hypothesized to be a consequence of the “hairy” nature of shish. Our results have large implications for process modelling, since they suggest that for injection molding type flows, crystallization kinetics can be considered independent of deformation history.
845.
Shuanglong Chen Mingguang Yao Ye Yuan Fengxian Ma Zhaodong Liu Bing Li Ran Liu Quanjun Li Bo Zou Tian Cui Bingbing Liu 《Journal of Raman spectroscopy : JRS》2015,46(4):400-405
Raman spectra of iodine species confined in one‐dimensional elliptical channels of AlPO4‐11 (AEL) crystals have been studied from room temperature down to −196 °C. As temperature decreases, thermal fluctuations of individual iodine molecules confined in AEL channels are slowed down and they prefer to rotate to channel axis direction, which increases the population of iodine molecules along channel axis (i.e., lying molecules and chains). Such temperature‐driven orientation transformation of iodine molecules is found to be reversible upon heating up to room temperature. The experimental observations are in good agreement with our theoretical simulations by molecular dynamics on low density iodine‐filled AEL crystals. We thus provide a new way to modulate the orientation of iodine molecules in nanochannels, which may have implications in low‐temperature‐sensitive nanoscale devices. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
846.
Qing Liu Zheyu Li Qingyun Ma Xuetian Li Guangyu Li Fanfei Zeng Zhongcai Shao 《印度化学会志》2022,99(6):100491
Polymer network gel method combines the advantages of solid-phase method and liquid phase method, triggering acrylamide (AM) radical polymerization in aqueous solution and N, N′- methylene bis acrylamide (MBAM) active double bond cross-linking reaction, forming polymer chains to form a three-dimensional network. The polymer network space formed by the gel is bound and evenly distributed to the ions in the solution, thereby reducing the contact and aggregation of molecules and achieving the purpose of uniform particle size and small particle size. The principle diagram of network gel is shown in Figure. Using cubic zinc acetate and ammonium molybdate tetrahydrate as raw materials, cubic ZnMoO4 negative electrode materials were prepared with polymer network gel method. The polymer network gel method has various effects on the structure, morphology and electrochemical properties of materials. Besides, the calcination temperature and calcination time were also the key factors to the electrochemical properties of the materials. In this paper, the effects of the ratio of monomer and crosslinker, calcination temperature and calcination time on ZnMoO4 materials were studied by single variable method, the preparation process was optimized, and its characterization and electrochemical tests were carried out. After 100 cycles, the optimized ZnMoO4 electrode has a discharge capacity of 374.0 mAh· g?1, 332.5, 263.5 and 177.1 mAh · g?1 at current densities of 0.1, 0.5, 1.0 and 2.0 A g?1, respectively. The electrochemical results show that the optimized ZnMoO4 has high capacity, large rate capability and excellent cycle stability. 相似文献
847.
Jiang Yuqi Gao Shuaibo Li Peng Ma Yongsong Yin Huayi Wang Dihua 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(7):2919-2928
Journal of Radioanalytical and Nuclear Chemistry - The waste LiCl–Li2O oxide reduction salt was solidified and transformed into sodalite by the spark plasma sintering method. Compared with... 相似文献
848.
Kim S. V. Baikenov M. I. Ainabaev A. A. Ibishev K. S. Meiramov M. G. Grigorieva V. P. Ma F. 《High Energy Chemistry》2022,56(3):201-207
High Energy Chemistry - Optimal conditions for producing ultrafine iron powder by combining the processes of electrolysis and high-voltage discharge have been determined. It has been established... 相似文献
849.
Yue Ma Fengchao Cui Huazhen Rong Jian Song Xiaofei Jing Yuyang Tian Guangshan Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2022,134(1):e202113682
Continuous microporous membranes are widely studied for gas separation, due to their low energy premium and strong molecular specificity. Porous aromatic frameworks (PAFs) with their exceptional stability and structural flexibility are suited to a wide range of separations. Main-stream PAF-based membranes are usually prepared with polymeric matrices, but their discrete entities and boundary defects weaken their selectivity and permeability. The synthesis of continuous PAF membranes is still a major challenge because PAFs are insoluble. Herein, we successfully synthesized a continuous PAF membrane for gas separation. Both pore size and chemistry of the PAF membrane were modified by ion-exchange, resulting in good selectivity and permeance for the gas mixtures H2/N2 and CO2/N2. The membrane with Br? as a counter ion in the framework exhibited a H2/N2 selectivity of 72.7 with a H2 permeance of 51844 gas permeation units (GPU). When the counter ions were replaced by BF4?, the membrane showed a CO2 permeance of 23058 GPU, and an optimized CO2/N2 selectivity of 60.0. Our results show that continuous PAF membranes with modifiable pores are promising for various gas separation situations. 相似文献
850.
Ma Qiang Zhou Bingjie Feng Zhigang Bai Jialing Zhang Lanying Liu Wei 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2045-2054
Journal of Radioanalytical and Nuclear Chemistry - Soil radon anomaly is a common phenomenon in karst areas. In this paper, the geochemical behavior of radium (Ra) in the process of carbonate rock... 相似文献