月別: 2019年12月

[Published online Journal of Computer Chemistry, Japan Vol.18, 166-168, by J-STAGE]
<Title:> Pd触媒を用いたアリルウレタンの分子内ヒドロアミノ化反応機構の理論的解明
<Author(s):> 河田　悠太, 林　慶浩, 高田　十志和, 川内　進
<Corresponding author E-Mill:> kawauchi.s.aa(at)m.titech.ac.jp
<Abstract:> Intramolecular hydroamination of allylurethane using the Pd-centered macrocycle catalyst was reported as an efficient continuous modification of oligo-functional allylurethanes. To clarify the mechanism of the hydroamination, quantum chemical calculation was performed for the model reaction. As a result, the cyclization in the hydroamination occurs via the initial deprotonation from the urethane N-H. In addition, the deprotonation was suggested to be a driving force for the transfer of the macrocyclic catalyst.
<Keywords:> 分子内ヒドロアミノ化, 量子化学計算, 反応機構, ロタキサン
<URL:> https://www.jstage.jst.go.jp/article/jccj/18/3/18_2019-0014/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.18, 164-165, by J-STAGE]
<Title:> フォルステライトガラス表面における水分子の分解メカニズム
<Author(s):> 久保　文音, 西澤　隼哉, 深澤　倫子
<Corresponding author E-Mill:> fukazawa(at)meiji.ac.jp
<Abstract:> To investigate the decomposition mechanisms of adsorbed H₂O molecules as a monolayer on the surface of forsterite glass, we performed molecular dynamics calculations. The decomposition phenomenon of H₂O molecules is observed at temperatures above 200 K. The equilibrium rate of the decomposed H₂O increases as the temperature increases and approaches 1.0 at temperatures above 500 K. The decomposed hydrogen forms MgO_xH_y or SiO₄H_z structures with MgO_x or SiO_z units in forsterite glass. The processes of decomposition and reformation of the structure units on the surface of forsterite glass have important implications for chemical evolution in interstellar spaces.
<Keywords:> Molecular dynamics calculation, Forsterite glass, Amorphous ice, Surface
<URL:> https://www.jstage.jst.go.jp/article/jccj/18/3/18_2019-0017/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.18, 159-161, by J-STAGE]
<Title:> 粒子法による量子波束の数値解析
<Author(s):> 廣野　史明, 岩沢　美佐子, 狩野　覚, 善甫　康成
<Corresponding author E-Mill:> zempo(at)hosei.ac.jp
<Abstract:> The particle method has no restriction on the particle arrangement, where the calculation is performed. The purpose is, by using this feature, to develop the method to analyze the dynamics of the electronic state. In order to describe the time evolution of the electronic state, we have developed a new method to solve the time-dependent wave equation, using the Bohmian that is very compatible with the particle method. In this form, there is also numerical instability in the region, where the value of the wave function is very small. We have applied our technique to the wave packet dynamics on harmonic potential and the analysis of interference by double slits as a simple system with analytical solution and easy to compare accuracy, and realized that both results are in good agreement.
<Keywords:> Keyword Symmetric smoothed particle hydrodynamics, Electronic structure calculation, Real-space calculation, Gaussian wave packet, Wave packet dynamics, Double slits, Interference
<URL:> https://www.jstage.jst.go.jp/article/jccj/18/3/18_2019-0015/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.18, 162-164, by J-STAGE]
<Title:> ルテニウム錯体における隣接アゴスティック相互作用の理論的解析
<Author(s):> 大橋　佐鳳子, 山中　聡美, 鷹野　景子
<Corresponding author E-Mill:> takano.keiko(at)ocha.ac.jp
<Abstract:> Abstract: Agostic interactions are covalent intramolecular interactions between a metal atom and a σ-bond in organometallic complexes. Sabo-Etienne et al. reported the Ru complex with two adjacent agostic interactions of C-H and B-H bonds in 2014. The objectives of the present study are to reveal whether the two adjacent agostic interactions have synergistic effects and to examine the difference between the C-H and B-H agostic bonds. Geometries were optimized for 11 Ru complexes (five reported complexes by Sabo-Etienne et al. and six model complexes) by density functional theory (DFT) calculations. Interaction energies based on natural bond orbital (NBO) analysis showed that the agostic interactions exhibit the multiplier effect and the B-H agostic bonds are less stable than the C-H ones. Bond lengths and vibrational frequencies of the bonds were consistent with the above results.
<Keywords:> Agostic Interaction, Organometallic Complexes, Density Functional Theory (DFT), Natural Bond Orbital (NBO) Analysis, Multiplier Effect
<URL:> https://www.jstage.jst.go.jp/article/jccj/18/3/18_2019-0019/_article/-char/ja/