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991.
Graphene Liquid Marbles as Photothermal Miniature Reactors for Reaction Kinetics Modulation 下载免费PDF全文
Wei Gao Hiang Kwee Lee Dr. Jonathan Hobley Prof. Tianxi Liu Dr. In Yee Phang Prof. Xing Yi Ling 《Angewandte Chemie (International ed. in English)》2015,54(13):3993-3996
We demonstrate the fabrication of graphene liquid marbles as photothermal miniature reactors with precise temperature control for reaction kinetics modulation. Graphene liquid marbles show rapid and highly reproducible photothermal behavior while maintaining their excellent mechanical robustness. By tuning the applied laser power, swift regulation of graphene liquid marble’s surface temperature between 21–135 °C and its encapsulated water temperature between 21–74 °C are demonstrated. The temperature regulation modulates the reaction kinetics in our graphene liquid marble, achieving a 12‐fold superior reaction rate constant for methylene blue degradation than at room temperature. 相似文献
992.
Spatial,Hysteretic, and Adaptive Host–Guest Chemistry in a Metal–Organic Framework with Open Watson–Crick Sites 下载免费PDF全文
Xiao‐Rong Lin Wei Chen Prof. Guang‐Hui Chen Prof. Xiao‐Chun Huang Prof. Dan Li 《Angewandte Chemie (International ed. in English)》2015,54(36):10454-10459
Biological and artificial molecules and assemblies capable of supramolecular recognition, especially those with nucleobase pairing, usually rely on autonomous or collective binding to function. Advanced site‐specific recognition takes advantage of cooperative spatial effects, as in local folding in protein–DNA binding. Herein, we report a new nucleobase‐tagged metal–organic framework (MOF), namely ZnBTCA (BTC=benzene‐1,3,5‐tricarboxyl, A=adenine), in which the exposed Watson–Crick faces of adenine residues are immobilized periodically on the interior crystalline surface. Systematic control experiments demonstrated the cooperation of the open Watson–Crick sites and spatial effects within the nanopores, and thermodynamic and kinetic studies revealed a hysteretic host–guest interaction attributed to mild chemisorption. We further exploited this behavior for adenine–thymine binding within the constrained pores, and a globally adaptive response of the MOF host was observed. 相似文献
993.
Radical Compatibility with Nonaqueous Electrolytes and Its Impact on an All‐Organic Redox Flow Battery 下载免费PDF全文
Dr. Xiaoliang Wei Dr. Wu Xu Dr. Jinhua Huang Dr. Lu Zhang Dr. Eric Walter Dr. Chad Lawrence Dr. M. Vijayakumar Dr. Wesley A. Henderson Dr. Tianbiao Liu Dr. Lelia Cosimbescu Dr. Bin Li Dr. Vincent Sprenkle Dr. Wei Wang 《Angewandte Chemie (International ed. in English)》2015,54(30):8684-8687
Nonaqueous redox flow batteries hold the promise of achieving higher energy density because of the broader voltage window than aqueous systems, but their current performance is limited by low redox material concentration, cell efficiency, cycling stability, and current density. We report a new nonaqueous all‐organic flow battery based on high concentrations of redox materials, which shows significant, comprehensive improvement in flow battery performance. A mechanistic electron spin resonance study reveals that the choice of supporting electrolytes greatly affects the chemical stability of the charged radical species especially the negative side radical anion, which dominates the cycling stability of these flow cells. This finding not only increases our fundamental understanding of performance degradation in flow batteries using radical‐based redox species, but also offers insights toward rational electrolyte optimization for improving the cycling stability of these flow batteries. 相似文献
994.
Far‐Red and Near‐IR AIE‐Active Fluorescent Organic Nanoprobes with Enhanced Tumor‐Targeting Efficacy: Shape‐Specific Effects 下载免费PDF全文
Andong Shao Prof. Dr. Yongshu Xie Shaojia Zhu Dr. Zhiqian Guo Shiqin Zhu Dr. Jin Guo Prof. Dr. Ping Shi Prof. Dr. Tony D. James Prof. Dr. He Tian Prof. Dr. Wei‐Hong Zhu 《Angewandte Chemie (International ed. in English)》2015,54(25):7275-7280
The rational design of high‐performance fluorescent materials for cancer targeting in vivo is still challenging. A unique molecular design strategy is presented that involves tailoring aggregation‐induced emission (AIE)‐active organic molecules to realize preferable far‐red and NIR fluorescence, well‐controlled morphology (from rod‐like to spherical), and also tumor‐targeted bioimaging. The shape‐tailored organic quinoline–malononitrile (QM) nanoprobes are biocompatible and highly desirable for cell‐tracking applications. Impressively, the spherical shape of QM‐5 nanoaggregates exhibits excellent tumor‐targeted bioimaging performance after intravenously injection into mice, but not the rod‐like aggregates of QM‐2. 相似文献
995.
Revealing the Charge‐Transfer Interactions in Self‐Assembled Organic Cocrystals: Two‐Dimensional Photonic Applications 下载免费PDF全文
Weigang Zhu Dr. Renhui Zheng Xiaolong Fu Prof. Hongbing Fu Prof. Qiang Shi Dr. Yonggang Zhen Dr. Huanli Dong Prof. Wenping Hu 《Angewandte Chemie (International ed. in English)》2015,54(23):6785-6789
A new crystal of a charge‐transfer (CT) complex was prepared through supramolecular assembly and it has unique two‐dimensional (2D) morphology. The CT nature of the ground and excited states of this new Bpe‐TCNB cocrystal (BTC) were confirmed by electron spin resonance measurements, spectroscopic studies, and theoretical calculations, thus providing a comprehensive understanding of the CT interactions in organic donor–acceptor systems. And the lowest CT1 excitons are responsible for the efficient photoluminescence (ΦPL=19 %), which can actively propagate in individual 2D BTCs without anisotropy, thus implying that the optical waveguide property of the crystal is not related to the molecular stacking structure. This unique 2D CT cocrystal exhibits potential for use in functional photonic devices in the next‐generation optoelectronic communications. 相似文献
996.
Crystalline Hetero‐Stereocomplexed Polycarbonates Produced from Amorphous Opposite Enantiomers Having Different Chemical Structures 下载免费PDF全文
Dr. Ye Liu Meng Wang Wei‐Min Ren Yue‐Chao Xu Prof. Dr. Xiao‐Bing Lu 《Angewandte Chemie (International ed. in English)》2015,54(24):7042-7046
Stereocomplexation is the stereoselective interaction between two opposite enantiomeric polymers through an interlocked orderly assembly. Most studies focus on the stereocomplex formation from the crystalline opposite enantiomers having the identical structure; nevertheless, rare examples were reported regarding the crystalline stereocomplexes from enantiomeric polymers having different chemical structures. Herein we show a strategy for polymer orderly assembly through the formation of crystalline hetero‐stereocomplexed polymeric materials by the cocrystallization of amorphous isotactic polycarbonates with different chemical structures and opposite configurations. The behaviors in the crystalline state are significantly different from that of the component enantiomeric polymers or their homo‐stereocomplexes. This study is expected to open up a new way to prepare various semicrystalline materials having a wide variety of physical properties and degradability. 相似文献
997.
A Facile and Universal Top‐Down Method for Preparation of Monodisperse Transition‐Metal Dichalcogenide Nanodots 下载免费PDF全文
Xiao Zhang Zhuangchai Lai Zhengdong Liu Chaoliang Tan Ying Huang Dr. Bing Li Dr. Meiting Zhao Prof. Linghai Xie Prof. Wei Huang Prof. Hua Zhang 《Angewandte Chemie (International ed. in English)》2015,54(18):5425-5428
Despite unique properties of layered transition‐metal dichalcogenide (TMD) nanosheets, there is still lack of a facile and general strategy for the preparation of TMD nanodots (NDs). Reported herein is the preparation of a series of TMD NDs, including TMD quantum dots (e.g. MoS2, WS2, ReS2, TaS2, MoSe2 and WSe2) and NbSe2 NDs, from their bulk crystals by using a combination of grinding and sonication techniques. These NDs could be easily separated from the N‐methyl‐2‐pyrrolidone when post‐treated with n‐hexane and then chloroform. All the TMD NDs with sizes of less than 10 nm show a narrow size distribution with high dispersity in solution. As a proof‐of‐concept application, memory devices using TMD NDs, for example, MoSe2, WS2, or NbSe2, mixed with polyvinylpyrrolidone as active layers, have been fabricated, which exhibit a nonvolatile write‐once‐read‐many behavior. These high‐quality TMD NDs should have various applications in optoelectronics, solar cells, catalysis, and biomedicine. 相似文献
998.
Substrate‐Tuned Catalysis of the Radical S‐Adenosyl‐L‐Methionine Enzyme NosL Involved in Nosiheptide Biosynthesis 下载免费PDF全文
Xinjian Ji Dr. Yongzhen Li Prof. Dr. Wei Ding Prof. Dr. Qi Zhang 《Angewandte Chemie (International ed. in English)》2015,54(31):9021-9024
NosL is a radical S‐adenosyl‐L ‐methionine (SAM) enzyme that converts L ‐Trp to 3‐methyl‐2‐indolic acid, a key intermediate in the biosynthesis of a thiopeptide antibiotic nosiheptide. In this work we investigated NosL catalysis by using a series of Trp analogues as the molecular probes. Using a benzofuran substrate 2‐amino‐3‐(benzofuran‐3‐yl)propanoic acid (ABPA), we clearly demonstrated that the 5′‐deoxyadenosyl (dAdo) radical‐mediated hydrogen abstraction in NosL catalysis is not from the indole nitrogen but likely from the amino group of L ‐Trp. Unexpectedly, the major product of ABPA is a decarboxylated compound, indicating that NosL was transformed to a novel decarboxylase by an unnatural substrate. Furthermore, we showed that, for the first time to our knowledge, the dAdo radical‐mediated hydrogen abstraction can occur from an alcohol hydroxy group. Our study demonstrates the intriguing promiscuity of NosL catalysis and highlights the potential of engineering radical SAM enzymes for novel activities. 相似文献
999.
Shaohua Guo Dr. Pan Liu Dr. Yang Sun Kai Zhu Dr. Jin Yi Prof. Mingwei Chen Prof. Masayoshi Ishida Prof. Haoshen Zhou 《Angewandte Chemie (International ed. in English)》2015,54(40):11701-11705
Recently, there has been great interest in developing advanced sodium‐ion batteries for large‐scale application. Most efforts have concentrated on the search for high‐performance electrode materials only in sodium half‐cells. Research on sodium full cells for practical application has encountered many problems, such as insufficient cycles with rapid capacity decay, low safety, and low operating voltage. Herein, we present a layered P2‐Na0.66Ni0.17Co0.17Ti0.66O2, as both an anode (ca. 0.69 V versus Na+/Na) and as a high‐voltage cathode (ca. 3.74 V versus Na+/Na). The full cell based on this bipolar electrode exhibits well‐defined voltage plateaus near 3.10 V, which is the highest average voltage in the symmetric cells. It also shows the longest cycle life (75.9 % capacity retention after 1000 cycles) in all sodium full cells, a usable capacity of 92 mAh g?1, and superior rate capability (65 mAh g?1 at a high rate of 2C). 相似文献
1000.
Monitoring of Endogenous Hydrogen Sulfide in Living Cells Using Surface‐Enhanced Raman Scattering 下载免费PDF全文
Dr. Da‐Wei Li Lu‐Lu Qu Kai Hu Prof. Dr. Yi‐Tao Long Prof. Dr. He Tian 《Angewandte Chemie (International ed. in English)》2015,54(43):12758-12761
Hydrogen sulfide (H2S) has emerged as an important gasotransmitter in diverse physiological processes, although many aspects of its roles remain unclear, partly owing to a lack of robust analytical methods. Herein we report a novel surface‐enhanced Raman scattering (SERS) nanosensor, 4‐acetamidobenzenesulfonyl azide‐functionalized gold nanoparticles (AuNPs/4‐AA), for detecting the endogenous H2S in living cells. The detection is accomplished with SERS spectrum changes of AuNPs/4‐AA resulting from the reaction of H2S with 4‐AA on AuNPs. The SERS nanosensor exhibits high selectivity toward H2S. Furthermore, AuNPs/4‐AA responds to H2S within 1 min with a 0.1 μM level of sensitivity. In particular, our SERS method can be utilized to monitor the endogenous H2S generated in living glioma cells, demonstrating its great promise in studies of pathophysiological pathways involving H2S. 相似文献