检索结果-南通市图书馆

第十五届全国化学动力学会议

作者：郑卫军 Beijing National Laboratory for Molecular Sciences（BNLMS） Institute of ChemistryChinese Academy of Sciences

In order to understand the microsolvation of salts in water, we investigated a series of salt-water clusters using photoelectron spectroscopy. The structures of these clusters and their corresponding neutrals were investigated with ab initio calculations and confirmed by the photoelectron spectroscopy experiments. Our studies show that the SSIP type of structures start to appear at n=5 in Li I（H2O）n clusters. However, the separation of the Cs+-I-ion pair by water is insignificant in Cs I（H2O）n clusters. For neutral Na Cl（H2O）n, the CIP structures are dominant at n ＜ 9. At n = 9-12, the CIP structures and SSIP structures of Na Cl（H2O）n are nearly degenerate in energy, coincident to the H2O:Na Cl molar ratio of Na Cl saturated solution and implying that the CIP and SSIP structures can coexist in concentrated solutions. For Li2SO4（H2O）n-cluster anions with n = 1–3, two kinds of isomers derived from the turtle-shaped and propeller-shaped structures of bare Li2SO4-were identified. These two kinds of isomers present similar structural and energetic features with increasing number of water molecules and thus are not distinguishable at n = 4–5. For the anionic Li2SO4（H2 O）n clusters, the water molecules prefer to firstly interact with one Li atom until fully coordinating it. While for the neutral Li2SO4（H2 O）n clusters, the water molecules interact with the two Li atoms alternately, therefore, show a pairwise solvation behavior. These results indicate that the structural variation and microsolvation in salt-water clusters are determined by the delicate balance between ion-ion, ion-water, and water-water interactions, which may have significant implications for the general understanding of salt effects in water solutions.

关键词： microsolvation salt-water clusters size-selected photoelectron

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

A Trade-off between Solvation and Collision Activation in Steering Competing E2 and S_(N)2 Dynamics

引用

Precision Chemistry 2024年第1期2卷 40-48页

作者： Hongyi Wang Xu Liu Siwei Zhao Gang Fu Wenqing Zhen Li Yang Jiaxu Zhang State Key Laboratory of Urban Water Resource and Environment MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001P.R.China College of Chemistry Liaoning UniversityShenyang 110036P.R.China

The prototypical E2 elimination and SN2 sub-stitution reactions between microsolvated fluoride and ethyl bromide show unexpected dynamic behaviors in mechanistic evolution driven by solvation and collision *** the steric effects,the gas-phase selectivity favors an E2 pathway barely dependent on collision ***,base solvation steers the reaction in an effective way toward substitution at a near-thermal energy,whereas the governing high-energy events retain *** dynamics simulations reproduce exper-imental findings and uncover a crucial solute-solvent coupling in determining such competing ***,collision activation can tune the underlying atomistic dynamics essentially in the reactant entrance channel and cause a mechanism *** features for the ubiquitous competing E2/SN2 dynamics remain quite unknown,providing unique insight into reaction selectivity for complex chemical networks.

关键词： E2/S_(N)2 Competition Atomistic Dynamics Reaction Mechanisms microsolvation Collision Activation

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

How Many Methanol Molecules Can Solvate a Glycine: a PBE1PBE Approach

引用

Chinese Journal of Structural Chemistry 2011年第11期30卷 1656-1671页

作者：王红磊邹昊胡勇军 MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science College of Biophotonics South China Normal University

microsolvation of glycine in methanol clusters is explored by the use of DFT calculation method. The lowest energy conformations within 16.72 kJ·mol^-1 of the glycine clustering with one to six methanol molecules, which are obtained at the B3LYP/6-31＋G（d） level of theory, are reoptimized at PBE1PBE/6-311＋G（d,p）. The calculated results agree with our previous results with B3LYP （Chin. J. Chem. Phys. 22 （2009） 577） that the clusters of two forms （Z- and N-form） tend to be isoenergetic when the number of the solvate molecules reaches six. Furthermore, this result is in good agreement with the experiment of the tryptophan-methanol clusters, implying that the present treatments are reasonable and reliable. The results also indicate that nine methanol molecules are not enough to fully solvate a glycine molecule, and a tentative estimation is obtained that ten methanol molecules may fully solvate a glycine molecule, which consists with the experiment results.

关键词： DFT microsolvation gibbs free energy amino acid glycine

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

Electronic Structure Calculations on the Microsolvated F-（H2O）2 + CH3I Reaction

Electronic Structure Calculations on the Microsolvated F-（H...

引用

第十三届全国量子化学会议

作者： Xu Liu Li Yang Jiaxu Zhang School of Chemistry and Chemical Engineering Harbin Institute of Technology

The potential energy profile of microhydrated fluorine ion reaction with methyl iodine has been characterized be extensive electricity structure calculations.[1] F-SN, OH-SN, and proton transfer reaction channels for the reaction F-（HO） +CH I were found with electricity structure calculations. Importantly, the OH-SN and proton transfer pathways are found to become competitive with the F-SN pathway, although the central barriers（-0.7, and 35.5 kcal/mol） for OH-SN and proton transfer pathways are higher than for the F-SN（-4.3 kcal/mol） pathway. Furthermore, with two water molecules bound to the reactant ion, the hydroxyl group of F-（H2 O）2 may attack carbon to induce the reactions leading to products P1 CHF + I+ 2 HO（F-SN2 channel）, P2 HF + CHOH + I+ HO（OH-SN channel） and PHF+ CHI+ 2HO（proton transfer channel）, as depicted in Fig. 1. The present study is vital to uncover the dynamics behaviors of solvated S2 reactions.

关键词： SN2 microsolvation potential energy profile

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Simulation Studies of Microsolvated Cl-（H2O）+CH3I SN2 Reaction

Simulation Studies of Microsolvated Cl-（H2O）+CH3I SN2 Reac...

引用

第十三届全国量子化学会议

作者： Meng Gu Li Yang Jiaxu Zhang School of Chemistry and Chemical Engineering Harbin Institute of Technology

The study of microsolvation in the gas phase gives us a deeper understanding of solvent effects. Here, the dynamics of the S2 reaction of hydrated chloride with methyl iodide was revealed by direct dynamics simulations, showing distinct characteristics from unsolvation system. The reaction probability of the solvation system is rather lower than that of the unsolvation system. There are three major mechanism, i.e. direct rebound, direct stripping and indirect reactions. The fractions among these three mechanisms are 0.746:0.085:0.169. At the high collision energy（1.9 eV）, direct rebound is the most significant mechanism and the roundabout is most important among the indirect mechanisms. In general, for most trajectories, HO dissociation is simultaneous with collision and substitution for the S2 reaction. Only small fractions of indirect trajectories show HO leaves before or after CHCl is formed, which are almost roundabout or barrier recrossing mechanism. This study reveals how solute-solvent interactions affect the underlying dynamics.

关键词： SN2 microsolvation potential energy profile dynamics

来源： cnki会议评论

在线全文

cnki会议

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

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

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：