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991.
Rémi Andres Fenggang Sun Dr. Qian Wang Prof. Dr. Jieping Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202213831
We report herein an asymmetric Pictet–Spengler reaction of α-ketoesters. In the presence of a catalytic amount of simple alanine-derived squaramide and p-nitrobenzoic acid, reaction of tryptamines with methyl 2-oxoalkanoates afforded the corresponding 1-alkyl-1-methoxycarbonyl tetrahydro-β-carbolines (THBCs) in high yields and ee values. A primary kinetic isotope effect (KIE=4.5) using C2-deteurium-labelled tryptamine indicates that rearomatization through deprotonation of the pentahydro-β-carbolinium ion could be the rate- and enantioselectivity-determining step. A concise enantioselective total synthesis of (+)-alstratine A, a hexacyclic cagelike monoterpene indole alkaloid, featuring this reaction as a key step, was subsequently accomplished. Remeasurement of the [a]D value of the natural product indicates that natural alstratine A is dextrorotatory rather than levorotatory as it was initially reported in the isolation paper. 相似文献
992.
Dr. Xiaolong Zu Yuan Zhao Dr. Xiaodong Li Runhua Chen Weiwei Shao Li Li Panzhe Qiao Prof. Wensheng Yan Prof. Yang Pan Qian Xu Prof. Junfa Zhu Prof. Yongfu Sun Prof. Yi Xie 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202215247
Herein, we first design a model of reversible redox-switching metal–organic framework single-unit-cell sheets, where the abundant metal single sites benefit for highly selective CO2 reduction, while the reversible redox-switching metal sites can effectively activate CO2 molecules. Taking the synthetic Cu-MOF single-unit-cell sheets as an example, synchrotron-radiation quasi in situ X-ray photoelectron spectra unravel the reversible switching CuII/CuI single sites initially accept photoexcited electrons and then donate them to CO2 molecules, which favors the rate-liming activation into CO2δ−, verified by in situ FTIR spectra and Gibbs free energy calculations. As an outcome, Cu-MOF single-unit-cell sheets achieve near 100 % selectivity for CO2 photoreduction to CO with a high rate of 860 μmol g−1 h−1 without any sacrifice reagent or photosensitizer, where both the activity and selectivity outperform previously reported photocatalysts evaluated under similar conditions. 相似文献
993.
Linjun Qi Ming Dong Jinlong Qian Shuling Yu Prof. Xiaofeng Tong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(3):e202215397
Reductive elimination of alkyl−PdII−O is a synthetically useful yet underdeveloped elementary reaction. Here we report that the combination of an H-bonding donor [PyH][BF4] and AgNO3 additive under toluene/H2O biphasic system can enable such elementary step to form alkyl nitrate. This results in the Pd0-catalyzed asymmetric carbonitratations of (Z)-1-iodo-1,6-dienes with (R)-BINAP as the chiral ligand, affording alkyl nitrates up to 96 % ee. Mechanistic studies disclose that the reaction consists of oxidative addition of Pd0 catalyst to vinyl iodide, anion ligand exchange between I− and NO3−, alkene insertion and SN2-type alkyl−PdII−ONO2 reductive elimination. Evidences suggest that H-bonding interaction of PyH⋅⋅⋅ONO2 can facilitate dissociation of O2NO− ligand from the alkyl−PdII−ONO2 species, thus enabling the challenging alkyl−PdII−ONO2 reductive elimination to be feasible. 相似文献
994.
Santhanamoorthi Nachimuthu Yi-Hui Kuo Dang Hoai Khanh Zhan-Jun Zhu Jyh-Chiang Jiang 《中国化学会会志》2023,70(3):349-358
The ability of the polymer-based graphitic carbon nitride (g-C3N4) as a gas sensor toward NO, NO2, CO, CO2, SO2, SO3, and O2 gasses is assessed using density functional theory (DFT) calculations in terms of energetic and electronic transport characteristics. In particular, this study is aimed to explore the role of zigzag and armchair edges of the g-C3N4 sheet on sensing performances. The electronic properties of adsorption systems, such as Bader charge analysis, band gaps, work function, and density of states (DOS), are used to understand the interaction between the adsorbed gas molecules and the g-C3N4 sheet. Our calculated results indicate that SOx (SO3 and SO2) gasses have higher adsorption energies on the g-C3N4 sheet than other gasses. Furthermore, the transport properties, such as current–voltage (I-V) and resistance-voltage (R-V) curves along the zigzag and armchair directions are calculated using the non-equilibrium Green's function (NEGF) method to understand the performance of the g-C3N4 sheet as a prominent conductive/resistive sensor. The I-V/R-V results indicate that the zigzag g-C3N4 sheet has excellent sensing ability toward SOx gasses at low applied voltages. However, the presence of H2O degrades the sensing performance of the armchair g-C3N4 sheet. Theoretical recovery time has also been calculated to evaluate the reusability of g-C3N4 sheet-based gas sensors. Our results reveal that the zigzag g-C3N4 sheet-based sensing device has a remarkably high sensitivity (>300%) and selectivity toward SOx gasses and has the potential to work in a complex environment. 相似文献
995.
Kang Sun Yunyang Qian Prof. Dr. Hai-Long Jiang 《Angewandte Chemie (International ed. in English)》2023,62(15):e202217565
Photocatalytic water splitting and carbon dioxide (CO2) reduction provide promising solutions to global energy and environmental issues. In recent years, metal-organic frameworks (MOFs), a class of crystalline porous solids featuring well-defined and tailorable structures as well as high surface areas, have captured great interest toward photocatalytic water splitting and CO2 reduction. In this review, the semiconductor-like behavior of MOFs is first discussed. We then summarize the recent advances in photocatalytic water splitting and CO2 reduction over MOF-based materials and focus on the unique advantage of MOFs for clarifying the structure-property relationship in photocatalysis. In addition, some representative characterization techniques have been presented to unveil the photocatalytic kinetics and reaction intermediates in MOF-based systems. Finally, the challenges, and perspectives for future directions are proposed. 相似文献
996.
Di Liu Jiyan Pei Prof. Xu Zhang Xiao-Wen Gu Prof. Hui-Min Wen Prof. Banglin Chen Prof. Guodong Qian Prof. Bin Li 《Angewandte Chemie (International ed. in English)》2023,62(12):e202218590
Developing porous materials for C3H6/C3H8 separation faces the challenge of merging excellent separation performance with high stability and easy scalability of synthesis. Herein, we report a robust Hofmann clathrate material (ZJU-75a), featuring high-density strong binding sites to achieve all the above requirements. ZJU-75a adsorbs large amount of C3H6 with a record high storage density of 0.818 g mL−1, and concurrently shows high C3H6/C3H8 selectivity (54.2) at 296 K and 1 bar. Single-crystal structure analysis unveil that the high-density binding sites in ZJU-75a not only provide much stronger interactions with C3H6 but also enable the dense packing of C3H6. Breakthrough experiments on gas mixtures afford both high separation factor of 14.7 and large C3H6 uptake (2.79 mmol g−1). This material is highly stable and can be easily produced at kilogram-scale using a green synthesis method, making it as a benchmark material to address major challenges for industrial C3H6/C3H8 separation. 相似文献
997.
Ye Qian Mi Wei Deng Chaohui He Prof. Dr. Osman Eksik Yi Ping Zheng De Kun Yao Dr. Xian Bin Liu Yan Hong Yin Ye Sheng Li Prof. Dr. Bao Yu Xia Prof. Dr. Zi Ping Wu 《Angewandte Chemie (International ed. in English)》2023,62(12):e202218621
Solid-state lithium batteries are promising and safe energy storage devices for mobile electronics and electric vehicles. In this work, we report a facile in situ polymerization of 1,3-dioxolane electrolytes to fabricate integrated solid-state lithium batteries. The in situ polymerization and formation of solid-state dioxolane electrolytes on interconnected carbon nanotubes (CNTs) and active materials is the key to realizing a high-performance battery with excellent interfacial contact among CNTs, active materials and electrolytes. Therefore, the electrodes could be tightly integrated into batteries through the CNTs and electrolyte. Electrons/ions enable full access to active materials in the whole electrode. Electrodes with a low resistance of 4.5 Ω □−1 and high lithium-ion diffusion efficiency of 2.5×10−11 cm2 s−1 can significantly improve the electrochemical kinetics. Subsequently, the batteries demonstrated high energy density, amazing charge/discharge rate and long cycle life. 相似文献
998.
Hao Chen Yishuo Sun Meihui Liu Fuyou Li Qian Peng Hui Huang 《Angewandte Chemie (International ed. in English)》2023,62(20):e202302629
The dual-ratiometric thermometry is one of highly accurate methods for microscopic thermal measurement in biological systems. Herein, a series of chromone derivatives with noncovalently intramolecular interactions (NIIs) were designed and synthesized for ratiometric thermometers. The triplet states of these organic compounds were systematically tuned upon regulating the conformation with NIIs to yield efficient room temperature phosphorescence and large wavelength difference between fluorescence and phosphorescence simultaneously. As a result, an unprecedent organic 3D dual-ratiometric thermometer was established based on the intensity ratio and lifetime ratio of fluorescence/phosphorescence vs temperature, which was used for in vitro and in vivo bio-thermometry with high accuracy. This work provides a novel method to achieve organic dual ratiometric thermometers via tuning the triplet excited states. 相似文献
999.
Rémi Lavernhe Dr. Qian Wang Prof. Dr. Jieping Zhu 《Angewandte Chemie (International ed. in English)》2023,62(22):e202303537
Transition-metal-catalyzed [4+2] heteroannulation of α,β-unsaturated oximes and their derivatives with alkynes has been developed into a powerful strategy for the synthesis of pyridines. It nevertheless lacks regioselectivity when unsymmetrically substituted alkynes are used. We report herein the unprecedented synthesis of polysubstituted pyridines by a formal [5+1] heteroannulation of two readily accessible building blocks. A copper-catalyzed aza-Sonogashira cross-coupling between β,γ-unsaturated oxime esters and terminal alkynes affords ynimines, which, without isolation, undergo an acid-catalyzed domino reaction involving ketenimine formation, 6π-electrocyclization and aromatization to afford pyridines. Terminal alkynes served as a one-carbon donor to the pyridine core in this transformation. Di- through pentasubstituted pyridines are accessible with complete regioselectivity and excellent functional-group compatibility. The first total synthesis of anibamine B, an indolizinium alkaloid with potent antiplasmodial activity, was accomplished featuring this reaction as a key step. 相似文献
1000.
Jiahui Dong Yahua Li Xiaofeng Wang Yajing Liu Kewei Ren Xuedi Liu Han Zhang Zongming Li Xinwei Han Hiroshi Uyama Qian Li 《Macromolecular bioscience》2023,23(10):2300113
Central airway stenosis is a condition that the diameter of the trachea or main bronchus shrinkage is caused by external compression or internal tissue hyperplasia, which can cause difficulty breathing, asphyxia, and even death. Airway stenting is an easy way to restore the patency of the central airway, but airway stents commonly used in clinical practice can lead to complications such as mucus plugging, bacterial infection, and granulation tissue hyperplasia. Moreover, the non-degradable characteristic makes it requires a second operation to remove, which has the potential to cause tissue damage. In this study, a biodegradable airway stent is fabricated by microinjection molding using the bioelastomer of poly (L-lactide-co-ε-caprolactone) as the matrix material. The airway stent has excellent mechanical properties and an appropriate degradation rate. The hydrophilic surface of the airway stent can inhibit mucus plugging. The loading of silver nanoparticles and cisplatin endows the stent with antibacterial and anti-hyperplastic functions. In vitro and in vivo experiments demonstrate that this study provides an antibacterial and anti-hyperplastic biodegradable airway stent with elastic properties to avoid secondary removal operation and reduce complications associated with mucus plugging, bacterial infection, and granulation tissue hyperplasia. 相似文献