检索结果-南通市图书馆

Synthesis of chiral phosphine derivatives through a copper（I）-catalyzed desymmetric SNAr reaction

Science China Chemistry 2025年

作者： Shuai Zhang Pei-zhi liu Yan-Bo Li Qi Zhang Jun-Zhao Xiao Yi-Fan Wang Tian-Yu Wei Jia-Wei Jiang Ye Wang Qian Peng Liang Yin Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences State Key Laboratory of Elemento-Organic Chemistry and Tianjin Key Laboratory of Biosensing and Molecular Recognition College of Chemistry Frontiers Science Center for New Organic Matter Nankai University Haihe Laboratory of Sustainable Chemical Transformations

Axially chiral phosphines are a class of extremely important ligands in asymmetric catalysis. Herein, an unprecedented copper（I）-catalyzed asymmetric SNAr reaction with HP（S）R2is uncovered, which delivers a series of axially chiral phosphine derivatives in high yields with excellent enantioselectivity. Furthermore, the diastereoselective reaction with the kinetic resolution of racemic HP（S）ArR proceeds smoothly, providing the products with moderate diastereoselectivity and excellent enantioselectivity. Control experiments indicate that HP（S）Ph2is much more active than HPPh2and HP（O）Ph2as the pronucleophile in the present reaction. It is found that the SNAr reaction （the first SNAr） proceeds in a desymmetric manner, providing the desired chiral products while a continued SNAr reaction （the second SNAr） slightly occurs in a kinetic resolution manner in the present catalytic system, which enhances the ee of the desired chiral products. DFTcalculations support a concerted reaction pathway rather than a step-wise mechanism. Finally, axially chiral olefin-phosphines produced by the present method work as suitable ligands in Pdcatalyzed asymmetric allylic substitution with C-, N-, and O-nucleophiles and Rh-catalyzed asymmetric addition of arylboronic acid to benzil.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于功能化COFs材料的样品前处理技术在新兴污染物中的研究进展

引用

分析测试学报 2025年第1期44卷 12-24页

作者：潘自宇刘智敏许志刚昆明理工大学理学院云南昆明650500

新兴污染物因具有环境持久性、生物累积性、生物毒性以及在环境中痕量存在等特点而备受全球众多国家关注。因此,对环境、食品以及生物样品中的新兴污染物进行高灵敏检测至关重要。传统样品前处理技术存在耗时长、吸附剂用量大,以及对不... 详细信息

新兴污染物因具有环境持久性、生物累积性、生物毒性以及在环境中痕量存在等特点而备受全球众多国家关注。因此,对环境、食品以及生物样品中的新兴污染物进行高灵敏检测至关重要。传统样品前处理技术存在耗时长、吸附剂用量大,以及对不稳定污染物的分析准确性差等缺点,因此,亟需开发设计具有高选择性、高传质效率的新型材料作为前处理技术的吸附剂,以实现新兴污染物的高选择、高灵敏检测。共价有机骨架材料(COFs),特别是功能化的COFs材料,因具有比表面积大、结构可设计、稳定且构筑基元丰富等诸多优点而被广泛用于新兴污染物的富集。该文主要综述了近年来功能化COFs材料的合成策略及其作为样品前处理吸附剂在环境、食品和生物样品中新兴污染物中的分析应用,并对该类材料的未来发展趋势进行了展望。

关键词：新兴污染物功能化COFs材料样品前处理技术

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

表面印迹微球在水相介质样品前处理中的应用研究进展

引用

分析测试学报 2025年第1期44卷 61-72页

作者：王思涛刘智敏许志刚昆明理工大学理学院云南昆明650500

氢键通常是分子印迹聚合物识别模板分子的主要机制,由于水分子等诸多影响因素带来的干扰,有效识别水环境中的分析物一直是分子印迹技术面临的一大挑战。表面印迹微球具有比表面积大和易于修饰等特性,能够被灵活运用以满足各种水相样品... 详细信息

氢键通常是分子印迹聚合物识别模板分子的主要机制,由于水分子等诸多影响因素带来的干扰,有效识别水环境中的分析物一直是分子印迹技术面临的一大挑战。表面印迹微球具有比表面积大和易于修饰等特性,能够被灵活运用以满足各种水相样品前处理的需求,是克服水相识别困难的有效方法之一。该文综述了近年来水相识别表面印迹微球的各种制备策略及其代表性应用,包括不同基底、亲水性识别、非氢键的协同识别和基于特殊组件的表面印迹微球;从作用力和识别机制层面讨论了在水相介质中识别分子时的干扰因素及其调控策略,并进一步介绍了表面印迹微球在水相样品前处理中的应用;最后探讨了表面印迹微球在水相样品前处理领域面临的挑战及未来研究趋势。

关键词：表面印迹微球水相识别样品前处理制备策略

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

基于共价有机骨架的水凝胶固相萃取在农药检测中的应用

引用

分析测试学报 2025年第1期44卷 145-154页

作者：孙蕾刘凌志刘玉碟沈晓芳新疆维吾尔自治区产品质量监督检验研究院新疆乌鲁木齐830011 江南大学食品学院江苏无锡214122

食品中农药残留超标对生物多样性以及人类健康造成潜在威胁。固相萃取技术广泛应用于农药的萃取,该方法的核心是吸附材料的选择。共价有机骨架(COFs)材料因其独特的优点在样品预处理中得到广泛的关注,而COFs的结构决定了材料的吸附性能... 详细信息

食品中农药残留超标对生物多样性以及人类健康造成潜在威胁。固相萃取技术广泛应用于农药的萃取,该方法的核心是吸附材料的选择。共价有机骨架(COFs)材料因其独特的优点在样品预处理中得到广泛的关注,而COFs的结构决定了材料的吸附性能,这对提高农药的萃取效果有重要作用。该研究制备了6种不同结构与性质的COFs(同一母体接枝不同官能团、具有不同带电性质、具有不同共轭结构),在不改变COFs结构的情况下,将其制备为COFs-海藻酸钠水凝胶(CACPs),建立了CACPs-分散固相萃取(CACPs-dSPE)方法,比较不同CACPs对氨基甲酸酯类、三唑类以及三嗪类农药的萃取效果。利用扫描电子显微镜、傅里叶变换红外光谱、X射线晶体衍射等方法对系列COFs以及系列CACPs的形貌、结构与性质进行表征。CACPs-dSPE结合高效液相色谱(HPLC)或紫外-可见分光光度法(UV-Vis)探究萃取效果,并结合理论计算模拟COFs与待测物的结合情况,探讨了不同CACPs对氨基甲酸酯类、三唑类以及三嗪类农药的吸附机理。结果表明:CACPs对不同类型农药的吸附性能是由其多孔结构性质(比表面积、孔径大小)和所负载COFs的固有结构协调决定,大的共轭结构、接枝羟基基团的COFs所制备的CACPs最有利吸附三类农药,其中Dt-TAPB-CACPs的萃取效果最佳。这为萃取农药过程中吸附材料的选择和设计提供了理论指导。

关键词：农药残留共价有机骨架 COFs-海藻酸钠水凝胶分散固相萃取(dSPE) 吸附机理

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Molecular simulation study of the microstructures and properties of pyridinium ionic liquid[HPy][BF_(4)]mixed with acetonitrile

引用

原子与分子物理学报 2025年第4期42卷 27-32页

作者： XU Jian-Qiang MA Zhao-Peng CHENG Si liu zhi-Cong ZHU Guang-Lai Department of Physics School of Physics and Electronic InformationAnhui Normal UniversityWuhu 241002China

The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this *** following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution *** results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient ***,the excess molar volume initially decreases,reaches a minimum,and then *** rules of radial distribution functions(RDFs)of characteristic atoms are *** increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then *** indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.

关键词： Pyridinium ionic liquids Thermodynamic properties Molecular dynamics simulation Radial distribution functions

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Size focusing of colloidal quantum dots under high monomer concentration

引用

Nano Research 2022年第8期15卷 7622-7630页

作者： Huiyan liu zhi liu Chaodan Pu School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

The diffusion-controlled growth mode is widely used to narrow the size distribution of colloidal quantum ***,this growth mode always suffers from size broadening at the later growth *** monitoring the growth process of CdS colloidal quantum dots,we show the size broadening is a result of different growth rates of CdS colloidal quantum dots(CQDs)with different *** concentration-dependent growth experiments demonstrate the different growth rates are caused by the different ligand permeabilities of CdS *** cubic ones have lower ligand permeability but higher saturated surface reaction rate than the noncubic ones,leading to unexpected narrower size distribution under higher monomer *** efficient narrowing can be obtained by the addition of chloride ions,which can increase the ligand permeability of all CdS CQDs,as well as the opposite discrepancies in ligand permeability and surface reaction between cubic and noncubic CdS *** photoluminescence(PL)full width at half maximum(FWHM)of CdS CQDs can be narrowed down to below 80 meV for PL peaks from 430 to 500 *** the inevitable usage of the ligands in the solution synthesis of colloidal nanocrystals,the influence of morphology difference on growth rate should be *** results can provide an alternative solution to realize size focusing for the synthesis of colloidal nanocrystals.

关键词： CdS quantum dots surface reaction monomer diffusion ligand permeability

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Temperature Responsive 3D Structure of Rod-like Bionanoparticles Induced by Depletion Interaction

引用

Chinese Journal of Polymer Science 2014年第10期32卷 1271-1271,1272-1275页

作者： zhi liu 牛忠伟 National Research Centre of Engineering Plastics Technical Institute of Physics and ChemistryChinese Academy of Sciences University of Chinese Academy of Sciences

Herein, we show that rod-like tobacco mosaic virus （TMV） can self-assemble into 3D bundled structures in aqueous solution using azobenzene modified Pluronics F127 block copolymers （Azo-F127） to induce depletion. The structures are characterized by both transmission electron microscopy and dynamic light scattering. The self-assembly process can be controlled reversibly by temperature. The formation of Azo-F127 hard spheres during the self-assembly is the main cause of this phenomenon.

关键词： Tobacco mosaic virus Pluronics Depletion interaction Self-assembly.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fuzzy adaptive tracking control within the full envelope for an unmanned aerial vehicle

引用

Chinese Journal of Aeronautics 2014年第5期27卷 1273-1287页

作者： liu zhi Wang Yong Department of Automation Science and Electrical Engineering Beihang University

Motivated by the autopilot of an unmanned aerial vehicle（UAV） with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller（FATC） is proposed. The controller consists of a fuzzy baseline controller and an adaptive increment, and the main highlight is that the fuzzy baseline controller and adaptation laws are both based on the fuzzy multiple Lyapunov function approach, which helps to reduce the conservatism for the large envelope and guarantees satisfactory tracking performances with strong robustness simultaneously within the whole envelope. The constraint condition of the fuzzy baseline controller is provided in the form of linear matrix inequality（LMI）, and it specifies the satisfactory tracking performances in the absence of uncertainties. The adaptive increment ensures the uniformly ultimately bounded（UUB） predication errors to recover satisfactory responses in the presence of uncertainties. Simulation results show that the proposed controller helps to achieve high-accuracy tracking of airspeed and altitude desirable commands with strong robustness to uncertainties throughout the entire flight envelope.

关键词： Flight control systems Full flight envelope Fuzzy adaptive tracking control Fuzzy multiple Lyapunov function Fuzzy T–S model Single hidden layer neural network

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Late-model Ionic Clusters of KNO_3 and Their Configurations

引用

Chemical Research in Chinese Universities 2005年第5期21卷 587-591页

作者： SHI Lei YANG zhi liu zhi-qiang liu Shu-ying School of Public Health Jilin University Changchun 130021 P. R. China Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China

Late-model ionic clusters of KNO3 were formed under the conditions of electrospray ionization. A series of peaks of the ionic clusters could be observed in the electrospray ionization mass spectra（ESIMS）. The general formulae of the ionic clusters were deduced to be K^ ＋（ KNO3 ） m and NO3^-（ KNO3 ）m. By referring to the crystal structure of KNOs , the possible configurations of these new typical ionic clusters were speculated based on the calculated data by means of the Gaussian-94^x computer program.

关键词： Cluster KNO3 Configuration Gaussian-94^* computer program

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

NUMERICAL SIMULATION OF PROPAGATION AND BREAKING PROCESSES OF A FOCUSED WAVES GROUP

引用

Journal of Hydrodynamics 2012年第3期24卷 399-409页

作者： HUANG Zong-liu LIN Peng-zhi State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China

A two-dimensional numerical wave flume is developed to study the focused waves group propagation and the consequent breaking processes. The numerical model is based on the Reynolds-Averaged Navier-Stokes （PANS） equations, with the standard k - c turbulence model to simulate the turbulence effects. To track the complicated and broken free-surface, the Volume Of Fluid （VOF） method is employed. The numerical model combines the ＂Partial Cell Treatment （PCT）＂ method with the ＂Locally Relative Stationary （LRS）＂ concept to treat the moving wave paddle so that various waves can be generated directly in a fixed Cartesian grid system. The theoretical results of the linear and nonlinear waves are used to validate the numerical wave flume firstly, and then a plunging breaking wave created by a focused waves group is simulated. The numerical results are compared to the experimental data and other simulation results, with very good agreements. The turbulence intensity, the flow field and the energy dissipation in the breaking processes are analyzed based on the numerical results. It is shown that the present numerical model is efficient and accurate for studying the waves group generation, the waves packet propagation, and the wave breaking processes.

关键词： focused waves group plunging breaking Volume Of Fluid (VOF) k - ε turbulence model irregular wave maker

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：