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Ni-Catalyzed Enantioselective Difunctionalization of Alkynes to Azepine Derivatives Bearing a Quaternary Center and an Unprotected Imine

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Chinese Journal of Chemistry 2024年第8期42卷 873-878页

作者： Jian Long Zhiwu Lu xiao-Lin Li Peng Xue wen-bo Liu Engineering Research Center of Organosilicon Compounds&Materials(Ministry of Education)and College of Chemistry and Molecular Sciences Wuhan UniversityWuhanHubei430072 China

Comprehensive Summary,The azepine ring is a prominent structural scaffold in biologically significant molecules. In this study, we present a Ni(II)-catalyzed asymmetric difunctionalization of alkynes, involving intermolecular regioselective arylation and intramolecular nitrile addition, enabling the synthesis of enantioenriched azepine derivatives. This reaction simultaneously installs an all-carbon quaternary stereocenter and introduces an unprotected imine functionality, showing great promise for subsequent transformations. The reaction exhibits good tolerance toward various functional groups, resulting in high yields and enantioselectivities. The synthetic utility of this methodology is further demonstrated through gram-scale synthesis and product derivatization. This research offers an efficient approach to the synthesis of seven-membered nitrogen heterocycles.

关键词： Nickel Asymmetric catalysis N-Heterocycles Alkyne functionalization Quaternary centers

Facile Synthesis of Polycarbonate Diol via Copolymerization of CO_(2) and Cyclohexene Oxide Catalysed by a Combination of One-Component Phosphonium borane Lewis Pair and Water

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Chinese Journal of Polymer Science 2023年第5期41卷 735-744,I0009页

作者： xiao-Wu Wang Ji-wen Hui Yu-Tao Li Yan-Ru Gu Zhi-bo Li State Key Laboratory Base of Eco-Chemical Engineering/College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China Key Laboratory of Biobased Polymer Materials Shandong Provincial Education Department/School of Polymer Science and EngineeringQingdao University of Science and TechnologyQingdao 266042China

Well-defined polycarbonate diol was successfully synthesized through a strategy using a combination of organocatalyst and *** strategy was less developed in organocatalyzed polymerization and frequently regarded as side ***,one-component phosphonium borane Lewis pairs PB1-PB8 were successfully applied in the copolymerization of CO_(2) and cyclohexene oxide(CHO)to generate poly(CHO-alt-CO_(2))carbonate(PCHC).Parameters of linker length and counter anion effects on the catalyst activity were *** was found that Lewis pair PB3 served as a dual initiator and catalyst in the copolymerization of CHO and CO_(2) with or without the presence of *** contrast,Lewis pair PB8 can serve as a true catalyst for the preparation of well-definedα,ω-hydroxyl PCHC *** was achieved by introducing a labile CF3COO group as counter anion through anion exchange reaction while water molecules acted as chain transfer *** function of trifluoroacetate group in the polymerization process was investigated in detail and possible mechanism was *** changing the amount of water and catalyst loading,PCHC diols with varied molecular weight(1.5 kg/mol to 7.5 kg/mol),low dispersities(Dbonate content(>99%)could be easily *** low molecular weight PCHC diol was used as a bifunctional macroinitiator for the ring-opening polymerization of L-lactide(LLA)to afford ABA triblock copolymer in one-pot synthesis.

关键词： Polycarbonate Phosphonium borane Lewis pair CO_(2)utilization Organocatalysis Ring-opening polymerization

Behind-plate overpressure effect of steel-encased reactive material projectile impacting thin aluminum plate

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Defence Technology（防务技术） 2022年第5期18卷 723-734页

作者： Qing-bo Yu Jia-hao Zhang Hong-wei Zhao Yan-wen xiao Hai-fu Wang Beijing Institute of Technology State Key Laboratory of Explosion Science and TechnologyBeijing100081China Academy of the Rocket Force Beijing100094China Equipment Project Management Center Army Equipment DepartmentBeijing100072China

Ballistic impact and sealed chamber tests were performed on the steel-encased reactive material projectile(SERMP)to understand its behind-plate overpressure effect when impacting the thin aluminum *** reactive material encased with a 1.5 mm thick 30CrMnSiNi2A steel shell was launched onto the initially sealed test chamber with a 3 mm thick 2024-T3 thin aluminum cover ***,the overpressure signals in the test chamber were recorded by pressure *** experimental results indicate an unusual behind-plate overpressure effect:as the density of the projectile increases from 6.43 g/cm^(3) to 7.58 g/cm^(3) by increasing the content of tungsten powder,although its total chemical energy decreases,it produces a higher behind-target overpressure at a lower impact velocity.A theoretical model is proposed to predict the reaction length of reactive material inside the projectile based on one-dimensional shock wave theory to understand this unexpected *** addition,the deviation between the actual energy release and the theoretical calculation results,also the variation of overpressure rise time are analyzed and *** the analyses show,when the SERMP successfully penetrates the cover plate,an increasing density of the reactive material inside the projectile always means that the delaying rarefaction wave effect,an increase of its internal pressure and strain rate *** factors lead to the increase of the overpressure limit velocity and reaction extent of the reactive material,while the overpressure rise time decreases.

关键词： Reactive materials Steel-encased reactive material projectile Over-pressure effect Overpressure limit velocity Energy release

Wide Band Gap Non-Fullerene Small Molecular Acceptors Containing Spirobifluorene and Benzotriazole with Three Different End-Capped Groups for P3HT-Based Organic Solar Cells

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Chinese Journal of Chemistry 2018年第5期36卷 392-398页

作者： xiaoyu wen bo xiao Ailing Tang Junyi Hu Chunhe Yang Erjun Zhou Department of Chemistry School of Science Beijing Jiaotong University Beijing 100044 China CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology Beijing 100190 China University of Chinese Academy of Sciences Beijing 200049 China

Spirofluorene （SF） and benzo[d][1,2,3]triazole （BTA） have been considered as promising building blocks to construct n-type photovoltaic materials. Herein, three new small molecule acceptors （SMAs） named BTA21, BTA23 and BTA27 with the structure of A2=A1-D-AI^A2 have been designed, in which SF and BTA were used as a central unit of D and bridged acceptor unit of A1, respectively. In addition, 3-ethylrhodanine, 2-（3-ethyl-4-oxothiazolidin-2-ylidene）malononitrile and malononitrile were chosen as terminal acceptor units to modulate the properties of the final SMAs. Three SMAs show wide optical band gaps （Eg） of 2.19, 2.15 and 2.22 eV, respectively, with gradually down-shift of the lowest unoccupied molecular orbital {LUMO） levels in the order of BTAZl, BTA23 and BTA27 depending on the electron-withdrawing capability of terminal acceptor units. BTA21 shows great advantages with respect to donor poly（3-hexylthiophene）（P3HT） over BTA23 and BTA27, such as well energy-level matching, complementary absorption and proper morpholgy, Concequently, P3HT：BTA21 shows the best power conversion efficiency （PCE） value of 3.28% with an open-circuit voltage （Voc） of 1.02 V, a short-circuit current （Jsc） of 5.45 ***-2 and a fill factor （FF） of 0.59. These results indicate that the terminal acceptor group end-capped in SMAs plays a significant role in controlling their optical, electronic, and photovoltaic properties.

关键词： benzotriazole organic photovoltaic P3HT small molecular acceptor wide band gap

Experimental Study on the Wavelengths of Two-Dimensional and Three-Dimensional Freak Waves

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China Ocean Engineering 2023年第1期37卷 154-164页

作者： CUI Cheng PAN wen-bo National Engineering Research Center for Port Hydraulic Construction Technology M.O.T.Tianjin Research Institute of Water Transport EngineeringTianjin 300456China

Freak waves are commonly characterized by strong-nonlinearity, and the wave steepness, which is calculated from the wavelength, is a measure of the degree of the wave nonlinearity. Moreover, the wavelength can describe the locally spatial characteristics of freak waves. Generally, the wavelengths of freak waves are estimated from the dispersion relations of Stokes waves. This paper concerns whether this approach enables a consistent estimate of the wavelength of freak waves. The two-(unidirectional, long-crested) and three-dimensional(multidirectional, shortcrested) freak waves are simulated experimentally through the dispersive and directional focusing of component waves, and the wavelengths obtained from the surface elevations measured by the wave gauge array are compared with the results from the linear, 3rd-order and 5th-order Stokes wave theories. The comparison results suggest that the 3rd-order theory estimates the wavelengths of freak waves with higher accuracy than the linear and 5th-order theories. Furthermore, the results allow insights into the dominant factors. It is particularly noteworthy that the accuracy is likely to depend on the wave period, and that the wavelengths of longer period freak waves are overestimated but the wavelengths are underestimated for shorter period ones. In order to decrease the deviation, a modified formulation is presented to predict the wavelengths of two-and three-dimensional freak waves more accurately than the 3rd-order dispersion relation, by regression analysis. The normalized differences between the predicted and experimental results are over 50% smaller for the modified model suggested in this study compared with the 3rd-order dispersion relation.

关键词： freak wave rogue wave wavelength three-dimension directional spread multidirectional wave

Intersectional nanotwinned diamond-the hardest polycrystalline diamond by design

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npj Computational Materials 2020年第1期6卷 653-659页

作者： Jianwei xiao Bin wen bo Xu Xiangyi Zhang Yanbin Wang Yongjun Tian Center for High Pressure Science State Key Laboratory of Metastable Materials Science and TechnologyYanshan University066004 QinhuangdaoChina Center for Advanced Radiation Sources University of ChicagoChicagoIL 60439USA

The hardness of nanotwinned diamond(nt-diamond)is reported to be more than twice that of the natural diamond,thanks to the fine spaces between twin boundaries(TBs),which block dislocation propagation during *** this work,we explore the effects of additional TBs in nt-diamond using molecular dynamics(MD)calculations and introduce a novel intersectional nanotwinned diamond(int-diamond)template for future laboratory *** hardness of this int-diamond is predicted by first analyzing individual dislocation slip modes in twinned grains and then calculating the bulk properties based on the Sachs *** we show that the hardness of the int-diamond is much higher than that of *** hardening mechanism of intdiamond is attributed to the increased critical resolved shear stress due to the presence of intersectional TBs in nt-diamond;this result is further verified by MD *** work provides a new strategy for designing new super-hard materials in experiments.

关键词： dislocation intersection diamond

A BiGRU joint optimized attention network for recognition of drilling conditions

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Petroleum Science 2023年第6期20卷 3624-3637页

作者： Ying Qiao Hong-Min Xu wen-Jun Zhou bo Peng Bin Hu xiao Guo National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina School of Computer Science Southwest Petroleum UniversityChengdu610500SichuanChina Information Management Center of Sinopec Southwest Oil and Gas Branch Chengdu610500SichuanChina

The identification and recording of drilling conditions are crucial for ensuring drilling safety and efficiency. However, the traditional approach of relying on the subjective determination of drilling masters based on experience formulas is slow and not suitable for rapid drilling. In this paper, we propose a drilling condition classification method based on a neural network model. The model uses an improved Bidirectional Gated Recurrent Unit (BiGRU) combined with an attention mechanism to accurately classify seven common drilling conditions simultaneously, achieving an average accuracy of 91.63%. The model also demonstrates excellent generalization ability, real-time performance, and accuracy, making it suitable for actual production. Additionally, the model has excellent expandability, which enhances its potential for further application.

关键词： Drilling condition classification BiGRU Machine learning Attention mechanism

Study on reaction characteristics of phenolic hydroxyl in coal by using the model compound during direct coal liquefaction

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Journal of Coal Science & Engineering(China) 2013年第4期19卷 540-545页

作者： bo-wen MA xiao-Su ZHU wen-bo LI xiao-Jing ZHANG Shu-Feng DU State Key Laboratory of Coal Mining and Clean Utilization Beijing 100013 China Beijing Research Institute of Coal Chemistry China Coal Research Institute Beijing 100013 China

The reaction characteristics of phenolic hydroxyl group were studied under the conditions of direct coal liquefaction. 2-naphthol was used as a coal model compound in this study. Under the conditions of with and without catalysts, a series of experiments were conducted at different temperatures, pressures and reaction time. Gas chromatography-mass spectrometry and gas chromatography were used to identify and quantify the reactants and products respectively. The conversion of 2-naphthol rises with the increase of reaction temperature, initial pressure and catalyst amount. The results indicated that tem- perature had a significant effect on 2-naphthol conversion, which promoted the dehydroxylation reaction. However, initial pressure had an important influence on the hydrogenation of 2-naphthol and naphthalene. The iron catalyst plays a significant role of cracking instead of hydrogenation. It is concluded that the harsh reaction conditions of high temperature, high pressure, and more catalyst are conducive to promoting dehydroxylation of 2-naphthol. The reaction mechanism was put forward based the experimental results, in which 2-tetralone was an intermediate.

关键词： direct coal liquefaction model compound phenolic hydroxyl reaction characteristics

A Morphological Study of Two Young Multipolar Planetary Nebulae

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Research in Astronomy and Astrophysics 2023年第3期23卷 170-182页

作者： Shi-bo wen Chih-Hao Hsia xiao-Xi Kang Rui Chen Tao Luo State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and Technology.MacaoChina The Laboratory for Space Research Faculty of ScienceThe University of Hong KongChina Deep Space Exploration Laboratory Beijing 100043China Lunar Exploration and Space Engineering Center China National Space AdministrationBeijing 100190China Shien-Ming Wu School of Intelligent Engineering South China University of TechnologyGuangzhou 511442China Zhuhai bojay Electronics Co. Ltd.Zhuhai 519075China

We carry out an optical morphological and infrared spectral study for two young planetary nebulae(PNs)Hen2-158 and Pe 1-1 to understand their complex shapes and dust *** Space Telescope optical images reveal that these nebulae have several bipolar-lobed structures and a faint arc with a clear boundary is located at the northwestern side of Pe *** presence of this arc-shaped structure suggests that the object interacts with its nearby interstellar *** IRS spectroscopic observations of these young nebulae clearly show prominent unidentified infrared emission features and a weak silicate band in Pe 1-1,indicating that Hen 2-158 is a carbonrich nebula and Pe 1-1 has a mixed chemistry dust ***,we construct two three-dimensional models for these PNs to realize their intrinsic *** simulated models of the nebulae suggest that multipolar nebulae may be more numerous than we *** analyses of spectral energy distributions for Hen 2-158 and Pe 1-1 show that they have low luminosities and low stellar effective temperatures,suggesting that these nebulae are young PNs.A possible correlation between typical multipolar young PNs and nested nebulae is also discussed.

关键词： northwestern stellar planetary