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991.
New polyoxamides, poly(m-xylylene oxamide) (PMXD2) and its copolymer with 2-methyl-1,5- pentanediamine (P(MXD2/M52)) with relative viscosity up to 4.6 were synthesized via spray/solid state polymerization. The obtained polyoxamides were characterized by FTIR, NMR, WAXD, DSC and TGA. The Tm of the copolymers decreased with increasing percentage of poly(2-methyl-1,5- pentaneoxamide) (PM52) in the copolymer from 346°C for 100% poly(meta-xylyleneoxamide) (PMXD2) to 277°C for copolymers of PMXD/PM52 (60/40). TGA analysis revealed that the thermal stability of the copolymers compared well with commercial PA6 and XRD studies suggested the copolymers possessed high crystallinity. DMA profile of the PMXD/PM52 (70/30) copolymer showed better mechanical performance with a storage modulus of about 7.2 GPa as compared to 1.8 GPa of PA6 at 25°C. 相似文献
992.
993.
Chune Dong Junlong Zhang Liangfu Zhang Zuolong Yu 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):e21-e21
The crystal structure of the new chiral complex (1R,2R)‐1,2‐diphenyl‐1,2‐bis(8‐quinolinesulfonylamino)‐ ethylenediamine–acetone (1/1), C32H26N4O4S2.C3H6O, is reported. The conformation of the C32H26N4O4S2 (BQSDA) molecule is determined by a bifurcated N—H?N hydrogen‐bond system. The acetone of solvation is linked to the BQSDA molecule by an N—H?O hydrogen bond. 相似文献
994.
Xiaodong Jia Xingzeng Zhao Ming Wang Yu Chen Yunfa Dong Xu Feng 《Chemistry of Natural Compounds》2008,44(6):692-695
Two new coumarin biosides, tert-O-β-D-apiofuranosyl-(1→6)-O-β-D-glucopyranosyl-byakangelicin (1) and 2′-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranosyl-peucedanol (2), were isolated from the fresh roots of Angelica dahurica. The structures of the new compounds were elucidated on the basis of spectral analysis.
Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 561–563, November–December, 2008. 相似文献
995.
Dong‐E Wang Feng Wang Xiang‐Gao Meng Yu Ding Li‐Li Wen Dr. Dong‐Feng Li Prof. Dr. She‐Ming Lan 《无机化学与普通化学杂志》2008,634(14):2643-2648
Three inorganic‐organic hybrid frameworks [Mn(HIMDC)(4,4′‐bipyo)0.5(H2O)]n (1) , [Cd(H2IMDC)2(2,2′‐bipyo)] (2) and [Ca(HIMDC)(H2O)2·H2O]n (3) (H3IMDC = 4,5‐imidazoledicarboxylate; 4,4′‐bipyo = 4,4′‐bipyridine‐N,N′‐dioxide; 2,2′‐bipyo= 2,2′‐bipyridine‐N,N′‐dioxide) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra, TG analysis and the single crystal diffraction. Both compounds 1 and 3 exhibit 2D layers while 2 is a monomer. It is noteworthy that compound 2 exhibits strong fluorescent emission in the solid state at room temperature. 相似文献
996.
Guodong Chen Jinran Sun Jiedong Li Dr. Xiaofan Du Gaojie Xu Prof. Shanmu Dong Prof. Guanglei Cui 《Angewandte Chemie (International ed. in English)》2023,62(31):e202306141
The Germanium (Ge), as a fast-charging and high specific capacity (1568 mAh g−1) alloy anode, is greatly hampered in practical application by poor cyclability. To date, the understanding of cycling performance degradation remains elusive. This study illustrates that, contrary to conventional beliefs, most of the Ge material in failed anodes still retains good integrity and does not undergo severe pulverization. It is revealed that capacity degradation is clearly correlated to the interfacial evolution of lithium hydride (LiH). Tetralithium germanium hydride (Li4Ge2H), as a new species derived from LiH, is identified as the culprit of Ge anode degradation, which is the dominant crystalized component in an ever-growing and ever-insulating interphase. The significantly increased thickness of the solid electrolyte interface (SEI) is accompanied by the accumulation of insulating Li4Ge2H upon cycling, which severely retards the charge transport process and ultimately triggers the anode failure. We believe that the comprehensive understanding of the failure mechanism presented in this study is of great significance to promoting the design and development of alloy anode for the next generation of lithium-ion batteries. 相似文献
997.
Weidong Shang Sheng‐Nan Su Rong Shi Ze‐Dong Mou Guo‐Qiang Yu Xia Zhang Dawen Niu 《Angewandte Chemie (International ed. in English)》2021,60(1):385-390
We here report glycosyl sulfoxides appended with an aryl iodide moiety as readily available, air and moisture stable precursors to glycosyl radicals. These glycosyl sulfoxides could be converted to glycosyl radicals by way of a rapid and efficient intramolecular radical substitution event. The use of this type of precursors enabled the synthesis of various complex C‐linked glycoconjugates under mild conditions. This reaction could be performed in aqueous media and is amenable to the synthesis of glycopeptidomimetics and carbohydrate‐DNA conjugates. 相似文献
998.
Hongwu Jiang Kaiwen Li Shuangfeng Dong Prof. Zhuqi Chen Prof. Guochuan Yin 《European journal of organic chemistry》2023,26(35):e202300598
Transition-metal-catalyzed oxidative C−H amination reactions are among the most attractive topics in organic synthesis to construct nitrogen-containing motifs. The challenge is that most of these reactions employed stoichiometric oxidants to achieve satisfied catalytic efficiencies. Herein, we report a Pd(II)/LA-catalyzed (LA: Lewis acid) oxidative C−H amination reaction of 2-acetaminobiphenyls to construct carbazoles by using dioxygen balloon as the sole oxidant source, and the presence of LA sharply improved the catalytic efficiency of Pd(OAc)2. Remarkably, in certain cases, the deacetylation of the annulation product happened under standard conditions to afford free carbazoles as the final product. The H/D exchange studies confirmed the reversibility of C−H activation and also disclosed multiple C−H activation sites by using −NAc and −NTs as the directing groups. In addition, the palladacycle compound was identified through 1H NMR characterizations and proved to be the intermediate prior to the carbazole formation. 相似文献
999.
Dr. Pengyang Xin Linqi Xu Wenpei Dong Linlin Mao Prof. Jingjing Guo Dr. Jingjing Bi Dr. Shouwei Zhang Yan Pei Prof. Chang-Po Chen 《Angewandte Chemie (International ed. in English)》2023,62(8):e202217859
Different types of natural K+ channels share similar core modules and cation permeability characteristics. In this study, we have developed novel artificial K+ channels by rebuilding the core modules of natural K+ channels in artificial systems. All the channels displayed high selectivity for K+ over Na+ and exhibited a selectivity sequence of K+≈Rb+ during the transport process, which is highly consistent with the cation permeability characteristics of natural K+ channels. More importantly, these artificial channels could be efficiently inserted into cell membranes and mediate the transmembrane transport of K+, disrupting the cellular K+ homeostasis and eventually triggering the apoptosis of cells. These findings demonstrate that, by rebuilding the core modules of natural K+ channels in artificial systems, the structures, transport behaviors, and physiological functions of natural K+ channels can be mimicked in synthetic channels. 相似文献
1000.
Small molecular biothiols, cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), play important roles in organisms, and their concentration levels are indicative of some human diseases. Herein we report an organic dye-conjugated β-diketonate-Eu3+ complex, [Eu(NBD-keto)3(DPBT)] (NBD-keto: 7-nitro-2,1,3-benzoxadiazole (NBD)-conjugated to 1,1,1,2,2-pentafluoro-5-phenyl-3,5-pentanedionate through a “O” ether bond; DPBT: 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine), which acts as a unique luminescent probe for detecting and discriminating biothiols. [Eu(NBD-keto)3(DPBT)] itself is not luminescent due to intramolecular interactions between NBD and β-diketonate-Eu3+ moieties. Upon reaction with biothiols, the β-diketonate-Eu3+ complex [Eu(keto)3(DPBT)] is generated, which emits long-lived red emission at 610 nm. Meanwhile, three biothiol-substituted NBD derivatives that exhibit different luminescence behaviors, green emissive (short-lived) NBD-NR (R=Cys or Hcy) at 540 nm and non-luminescent NBD-SR (R=GSH), are also generated. These luminescence response behaviors allow time-gated and steady-state luminescence modes to be combined for detecting total biothiols and discriminating GSH and Cys/Hcy. Using this probe, the quantitative detection and discrimination of GSH and Cys/Hcy in lysis solutions of HeLa cells were realized, which revealed the potential of the probe for biomedical applications. 相似文献