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chemical Research in Chinese Universities 2002年第3期18卷 372-374页

作者： REN Yu-jie YU Li-mei YANG Xue-feng CHEN Hui-lin BAI Ri-xia Department of Chemistry Dalian University of TechnologyDalian 116024P.R.China Dalian Institute of chemical Physics Chinese Academy of SciencesDalian 116023P.R.China Dalian Nationality College Dalian 116600P.R.China

Organotin compounds have attracted attention as an optimal model for antitumour agents due to the function of the interesting intramolecular O→Sn coordination. Our recent concern has been focused on the preparation of (Z)-l-[2-(tri-arylstannyl)vinyl]-cyclooctanolM. In order to find more appropriate compounds used as anticancer agents and explore the effect of the coordinate O→Sn interaction to the antitumor activity, the new compounds were halodemetallated and charac-terized.

关键词： Organotin Halodemetallation Correlation chemical shift Electronegativity

Computational evaluation concerning the deviation of the atoms in 1-and 4-postions on the six-member ring and the effects on ^(1)HNMR chemical shift

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中国化学前沿:英文版 2011年第2期6卷 91-97页

作者： Asadollah FARHADI Mohammad Ali TAKASSI Hamid Reza MEMARIAN Mousa SOLEYMANI Faculty of Science University of Petroleum TechnologyAhwaz 61981-44471Iran Department of Chemistry Faculty of ScienceUniversity of IsfahanIsfahan 81746-73441Iran

Density functional theory(DFT)calculations were carried out on some cyclohexane derivatives to investigate the deviation atoms on the 1-and 4-positions of chair *** deviations of chair plane of two position in the cyclohexane derivatives were calculated at the B3LYP/6–31++G(d,p)***,we investigated the correlation between deviations of two positions from chair plane on the chemical shift hydrogen atoms on the 4-position.

关键词： cyclohexane heterocyclohexane deviation B3LYP/6-31++G(d p) chemical shift

Correlation of ^1H NMR chemical shift for Aqueous Solutions by Statistical Associating Fluid Theory Association Model

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Chinese Journal of chemical Engineering 2005年第2期13卷 280-284页

作者：许波李浩然王从敏许映杰韩世钧 Department of Chemistry Zhejiang University Hangzhou 310027China

1H NMR chemical shifts of binary aqueous mixtures of acylamide, alcohol, dimethyl sulphoxide (DMSO), and acetone are correlated by statistical associating fluid theory (SAFT) association model. The comparison between SAPT association model and Wilson equation shows that the former is better for dealing with aqueous solutions. Finally, the specialties of both models are discussed.

关键词： Statistical associating fluid theory (SAFT) association model NMR chemical shift aqueous solution

Simulation of ^(13)C NMR chemical shifts of carbinol carbon atoms using quantitative structure-spectrum relationships

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Journal of Central South University 2011年第2期18卷 323-330页

作者：戴益民黄可龙李浔曹忠朱志平杨道武 School of Chemistry and chemical Engineering Central South University Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation Changsha University of Science and Technology

A quantitative structure-spectrum relationship (QSSR) model was developed to simulate 13C nuclear magnetic resonance (NMR) spectra of carbinol carbon atoms for 55 alcohols. The proposed model,using multiple linear regression,contained four descriptors solely extracted from the molecular structure of compounds. The statistical results of the final model show that R2= 0.982 4 and S=0.869 8 (where R is the correlation coefficient and S is the standard deviation). To test its predictive ability,the model was further used to predict the 13C NMR spectra of the carbinol carbon atoms of other nine compounds which were not included in the developed model. The average relative errors are 0.94% and 1.70%,respectively,for the training set and the predictive set. The model is statistically significant and shows good stability for data variation as tested by the leave-one-out (LOO) cross-validation. The comparison with other approaches also reveals good performance of this method.

关键词： carbinol carbon atom ^13C nuclear magnetic resonance chemical shift topological indices quantitative structure-spectroscopy relationship

Structures and Hydrogen Bonding Interactions in Urea-water System Studied by All-atom MD Simulation and chemical shifts in NMR Spectrum

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Chinese Journal of chemical Physics 2009年第5期22卷 511-516,I0002页

作者： Rong Zhang Guan-sheng Zhao Wen-juan Wu Lab of Physical Chemistry College of Pharmacy Guangdong Pharmaceutical University Guangzhou 510005 China

The interactions and structures of the urea-water system are studied by an all-atom molecular dynamics （MD） simulation. The hydrogen-bonding network and the radial distribution functions are adopted in MD simulations. The structures of urea-water mixtures can be classified into different regions from the analysis of the hydrogen-bonding network. The urea molecule shows the certain tendency to the self-aggregate with the mole fraction of urea increasing. Moreover, the results of the MD simulations are also compare with the chemical shifts and viscosities of the urea aqueous solutions, and the statistical results of the average number hydrogen bonds in the MD simulations are in agreement with the experiment data such as chemical shifts of the hydrogen atom and viscosity.

关键词： All-atom simulation chemical shift Viscosity Urea-water system Hydrogen bond

Ab Initio Prediction of ^(29)Si-NMR chemical shifts

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Journal of Ocean University of Qingdao 2002年第1期1卷 63-65页

作者： CHU Shidong LI Yingxia SONG Ni GUAN Huashi Institute of Marine Drugs Ocean University of QingdaoQingdao 266003P.R.China

The ability of several ab initio models to predict experimental 29Si-NMR chemical shift is examined. The shielding values of trimethylsilyl chloride (A), t-butyldimethylsilyl chloride (B) and allyltrimethylsilane (C) are calculated by GIAO , CSGT and IGAIM methods, using HF/6-31G*, B3LYP/6-31G*, HF/6-311+G **, B3LYP/6-311+G ** and MPW1PW91/6-311+G ** models respectively. The 29Si chemical shifts calculated by GIAO method using HF/6-311+G ** model are highly in agreement with those obtained experimentally. All of the models above reproduce the trends of chemical shifts in all cases studied, suggesting that the models are of practical value.

关键词： Si-NMR chemical shift ab initio prediction Density Functional Theory

Simulating electron momentum spectra of iso-C_2H_2 Cl_2 : A study of the core electronic structure

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Chinese Physics B 2014年第1期23卷 170-176页

作者：黄艳茹陈明明 Department of Physics Liaoning Shihua University

Electron momentum spectroscopy(EMS) has been used for the first time to study core electronic structure of isoC2H2Cl2. In the present work, the pronounced difference between ionization energies of two C1 score orbitals(2A1 and 3A1) is seen as a chemical shift of 3 eV, which is due to different chemical environments of the related carbon atoms. Both the calculated spherically averaged core electron momentum distributions(MDs) and three-dimensional electron momentum density maps show that these core molecular orbitals(MOs) 2A1and 3A1 exhibit strong atomic orbital characteristics in real and momentum space. However, the core states 2B2 and 4A1, which are almost degenerate and related to two equivalent atoms, exhibit notable differences between the momentum and position depictions. In contrast to the position space, the momentum density maps of these two core MOs highlight the interference effects which are due to the nuclear positions. The 2B2 orbital of iso-C2H2Cl2 is the antisymmetric counterpart of the 4A1 core orbital in real space. However, it relates to the 4A1 orbital by an exchange of maxima and minima in momentum space. Due to interference effects between electrons scattered from different atomic centers, modulations with a periodicity of 1.12 a.u. can be seen in the computed momentum densities, which tend to decay with increasing electron momenta. Accordingly, the EMS can not only effectively image the electronic structure of compounds by studying valence orbitals, but also provides direct information on the nature of the nuclear geometry by investigating the core states.

关键词： (e,2e) reaction chemical shift momentum distributions core orbitals

Theoretical Studies on Structures, Stabilities, NMR Spectra and Designing Methods of Dihedral Fullerenes of C3 Series

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chemical Research in Chinese Universities 2014年第6期30卷 1032-1043页

作者： LI Ping College of Chemistry Sichuan University Chengdu 610064 P. R. China

Using bowl shaped carbon intermediates to construct dihedral fullerenes is an advisable method. Assu- ming that cap shaped C21 extends the size through building pentagons and hexagons at the U and V clefts of the brims, a series of homologous carbon intermediates was generated, in which most of the members have been unknown up to now. The joins between these homologous intermediates gave the C3 dihedral series under the restriction of C3 sym- metrical axis. The investigations point out that the stabilities of these fullerenes not only relate to the shapes of cages and the co-planarities of polygons, but also associate with the equalizations of bond lengths and the pentagonal dis- tributions. The stabilities reveal that the pentagonal distribution in cages is not negligible to the Jr delocalization, be- sides the co-planarities of hexagons and pentagons. Analyzing the possible Stone-Wales（SW） rearrangements in those fullerenes with dehydrogenated pyracyclene units（DPUs） can help us to find out the highly stable isomers. Based on the geometrical optimizations, the calculations provided the theoretical chemical shifts of unknown fullerenes and the data reconfirmed the existence of members C78 and C84. The symmetry adaptation analyses for the frontier orbitals support the formative mechanism of consecutive pentagonal and hexagonal fusions, but the simulated routes are more complicated than the pentagon road（PR） mechanism, which include not only C2 but also C3 additive reactions.

关键词： Dihedral fullerene Curvature Distortion Pentagon and hexagon chemical shift Stone-Wales(SW) ar-rangement Density functional theory

Accurate Prediction of NMR chemical shifts in Macromolecular and Condensed-phase Systems with the Generalized Energy-based Fragmentation Method

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Accurate Prediction of NMR Chemical Shifts in Macromolecular...

Studies on NaXe Clusters

第十三届全国量子化学会议

作者： Dongbo Zhao Ruiheng Song Wei Li Hao Dong Jing Ma Shuhua Li Institute of Theoretical and Computational Chemistry Nanjing University Kuang Yaming Honors School Nanjing University

The generalized energy-based fragmentation（GEBF） method is extended to allow calculations of NMR chemical shifts of macromolecular and condensed-phase systems feasible at a low computational *** this approach,NMR shielding constants in a large system are evaluated as a linear combination of the corresponding quantities from a series of small "electrostatically embedded" *** of NMR shielding constants from the GEBF-X（X = HF,DFT,…） method with those from the conventional quantum chemistry method for two representative systems verifies that the GEBF approach can reproduce the results of the conventional quantum chemistry method very *** procedure has further been applied to compute NMR shielding constants of a large foldamer and a supramolecular aggregate,and the N shielding constant for CH CN in the CHCl *** the former two systems,the predicted H chemical shifts are in good agreement with the experimental *** the CH CN/CHCl solution,the N shielding constant of CHCN is evaluated as the ensemble average of up to 200 sufficiently large CH CN/CHCl clusters from either classical or QM/MM MD *** results reveal that the gas-to-solution shift of 15 N based on PM6-DH+/MM MD simulations is in good accord with the experimental value,outperforming those based on classical MD simulations and the previous implicit IEF-PCM *** study unravels that the generation of representative liquid structures is critical in evaluating the NMR shielding constants of condensed phase ***,we have found that for various CHCN/CHCl clusters accurate predictions of NMR shielding constants with the GEBF-DFT method require an ultrafine integration grid for DFT *** same strategy should be adopted for other fragment-based methods if they are employed to predict NMR shielding constants of condensed phase systems.

关键词： chemical shift Macromolecular Condensed Phase Generalized Energy-based Fragmentation(GEBF)

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Chinese chemical Letters 2001年第9期12卷 833-834页

作者： Jia Chang LIANG Zhi LIU Yi Min SHEN Xian Ping SUN Xi Zi ZENG Xiao Yun LE Xiang Yun WANG De Min WANG Fu Chun YU Yong Ti CHEN College of sciences Civil Aviation Institute of ChinaTianjin 300300 Department of Chemistry Nankai UniversityTianjin 300071 Department of Radiology Wayne State UniversityDetroit MI 48201 USA Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Phys.&Math.The Chincse Academy of SciencesWuhan 430071 Institute of Heavy lon Physics Peking UniversityBeijing 100871

The chemical shift of Na-23 in excimer NaXe was measured by using nuclear magnetic resonance (NMR) spectra, which is in good agreement with the theoretical value obtained by ab initio calculations. The bond length, dissociation energy, dipole of NaXe and Mulliken charges at Na and Xe in NaXe were calculated, respectively. The spectra of ultraviolet (UV) fluorescence and surface-enhanced Raman scattering of NaXe were also measured.

关键词： Xenon-ion-implanted NaCl crystal NaXe chemical shift ab initio calculation