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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

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

Studies on NaXe Clusters

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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

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...

Theoretical Study on a 42 T Model of Beta Zeolite by Density Functional Theory Simulation

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 Journal of Structural Chemistry 2009年第10期28卷 1190-1196页

作者：辛益双黄崇品孙秀良张傑陈标华 State Key Laboratory of chemical Resource Engineering Beijing University of Chemical Technology

Density functional theory was applied to study the structure of Beta zeolite. A model cluster containing 41Si atoms, 1 Al atom, 70 O atoms and 29 H atoms was constructed. The model structures were optimized using the Becke＇s three-parameter hybrid method with the Lee-Yang-Parr correlation functional （B3LYP） and the 6-31G basis set applying the Gaussian03 program package. The NMR parameters were calculated to validate the rationality of the model. It was found that in the optimization models, all O-H bond lengths were in range of 0.984-0.985A^°, among which the model with O-H bond length of 0.98478A^° was more stable than the others. The ^1H and ^27Al chemical shifts of the most stable model were 4.03434 and 55.74 ppm, which were pretty consistent with Larry＇ s experimental data of 4.1 and 54 ppm. The relationship between other structure parameters and total relative electric energy has also been found. All the results exhibit that the 42 T （the total number of Si and Al atoms is 42） model has common properties of the standard of zeolite Beta.

关键词： Beta zeolite density functional theory (DFT) chemical shift

First Principles Calculation of Magnetic Resonance Properties of Cu<sub>2-<i>δ</i></sub>X (X = Se, S, Te)

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Journal of Applied Mathematics and Physics 2021年第6期9卷 1245-1256页

作者： Zhipeng Shao Chenglong Shi School of Science University of Shanghai for Science and Technology Shanghai China

In order to have a better understanding of the electronic structures and physical properties of Cu2-δX (X = Se, S, Te) copper chalcogenides. First principles were performed to calculate the chemical shift, band structure, and electron density of states of Cu2-δX (X = Se, S, Te). By comparing our calculation results with previous experimental works, we found that the predicted electronic structures of Cu2Se, Cu2Te and Cu2S transform from semimetal to semiconductor after adding on-site Coulomb U, which reflects the real properties of the materials. By using (Density Functional Theory) DFT + U method, the calculation result is close to the real electronic structure. The calculation result of chemical shift of adding U does not reach the ideal expectation, and the reason is not clear at present. In this paper, the theoretical electronic structures of Cu2Se, Cu2Te and Cu2S are better calculated by DFT + U method and compared with the actual properties. The effect of Cu-s electron on the chemical shift is understood, and a theoretical result of the chemical shift is calculated, which provides a powerful reference for the subsequent research and understanding of the electronic structure and physical properties of the compounds with S groups of Cu.

关键词： Copper Chalcogenides chemical shift First Principles Calculation

Adjacent frontier orbitals appoximation for calculation of nuclear magnetic resonance in transition metal

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Progress in Natural Science:Materials International 1999年第6期 73-75页

作者：王德民叶学其林熹徐晓松刘桂兰 Department of Automat Peking University Beijing 100871 China Graduate School 3Chinese Academy of Sciences Beijing 100039 China Department of Technical Physics Peking University Beijing 100871 China Department of Technical Physics Peking University Beijing 100871 China

An approximate calculation for chemical shift on transition atom and an exmaple are presented

关键词： nuclear magnetic resonance chemical shift transition metal adjacent frontier orbitals.

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TDE-85环氧树脂的NMR研究

TDE-85环氧树脂的NMR研究