月別: 2016年2月

[Published online Journal of Computer Chemistry, Japan Vol.14, 213-214, by J-STAGE]
<Title:> 2 アザスピロ環化合物における閉環反応の理論的研究
<Author(s):> 寺前　裕之, 須田　岬, 湯川　満, 林　浩輔, 高山　淳, 坂本　武史
<Corresponding author E-Mill:> teramae(at)gmail.com
<Abstract:> The geometric structures of the phenoxenium cation which is a cation intermediate of 2-azaspiro ring compounds (2-azaspiro[4.5]decane) from N-methoxy-N-prenylbenzamide are studied by means of the Hamiltonian algorithm with ab intio molecular orbital calculations at HF/3-21G level. The geometries are further refined with MP2/6-311G** level. We tried four substituted compounds with the methyl group. Among them only one compound with two methyl groups gives a ring-closure intermediate, which agrees well with the experimental results.
<Keywords:> Hamiltonian algorithm, Phenoxenium cation, 2-azaspiro[4.5]decane, Optimized structure, Substituent effect
<URL:> https://www.jstage.jst.go.jp/article/jccj/14/6/14_2015-0060/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.14, 215-216, by J-STAGE]
<Title:> Ru(0)触媒による共役ジエンとスチレンのクロスカップリング反応における置換基効果の理論的解明
<Author(s):> 出口　光, 大槻　恒太, 中村　沙季, 平野　雅文, 川内　進
<Corresponding author E-Mill:> skawauch(at)polymer.titech.ac.jp
<Abstract:> Mechanistic studies for linear cross-dimerization between 2,3-dimethylbuta-1,3-diene and para-substituted styrenes by a Ru(0) complex, Ru(η⁶-naphthalene) (η⁴ 1,5-COD), were performed computationally. The COD ligand is actually not a simple spectator ligand, it engages to assist the hydrogen migration steps. The computational studies verified the oxidative coupling step to govern the overall reaction as a rate-determining step. The reaction rate was found to be correlated well with the electronegativity of styrenes.
<Keywords:> oxidative coupling, cross-dimerization, Ru(0) complex, DFT calculations
<URL:> https://www.jstage.jst.go.jp/article/jccj/14/6/14_2015-0065/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.14, 211-212, by J-STAGE]
<Title:> 全原子モデルを用いた4-n-alkyl-4′-cyanobiphenyl (nCB)の分子動力学シミュレーション
<Author(s):> 高橋　祐貴, 石川　良, 川内　進
<Corresponding author E-Mill:> skawauch(at)polymer.titech.ac.jp
<Abstract:> Molecular dynamics simulation of 4-n-alkyl-4′-cyanobiphenyl series (nCB) using the full-atom model was carried out. We used a force field that was fitting the dihedral angle parameter and the LJ parameters of the AMBER Force Field against nCB. The dihedral angle parameter is set to reference the quantum chemical calculation, and the LJ parameters were fitted to reproduce the experimental data. By using the modified force field, experimental data such as isotropic-nematic phase transition temperature and density were reproduced.
<Keywords:> Molecular dynamics simulation, Full-atom model, Dihedral angle parameter, LJ parameter, Phase transition
<URL:> https://www.jstage.jst.go.jp/article/jccj/14/6/14_2015-0064/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.14, 203-205, by J-STAGE]
<Title:> 実空間実時間のTDDFTによる11-cis型レチナールの光吸収スペクトルの解析
<Author(s):> 田中　志歩, 遠越　光輝, 善甫　康成
<Corresponding author E-Mill:> shiho.tanaka.2a(at)stu.hosei.ac.jp
<Abstract:> We have applied time-dependent density functional theory (TDDFT) in real-time and real-space to 11-cis retinal to investigate the optical absorption. As the exchange-correlation functional, we use the usual LDA and B88, which is the simplest GGA to describe the correct asymptotic behavior. The calculated result of B88 is closer to that of experiment, compared to that of LDA. Our results indicate that, if the functional to express the correct asymptotic form is selected, more accurate results can be obtained. In our TDDFT calculation, the peak position is confirmed by the maximum entropy method, which is applied to the spectrum analysis to find the peak related to the optical absorption effectively.
<Keywords:> Real-time and real-space, Time-dependent density functional theory, 11-cisretinal, Density functionals, Correct asymptotic behavior, Maximum Entropy Method
<URL:> https://www.jstage.jst.go.jp/article/jccj/14/6/14_2015-0075/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.14, 206-208, by J-STAGE]
<Title:> 比較的大きな分子に対する内殻二重正孔分光
<Author(s):> 高橋　修
<Corresponding author E-Mill:> shu(at)hiroshima-u.ac.jp
<Abstract:> The ionization energies of single, double, and triple core-hole (SCH, DCH, and TCH) states were calculated for three isomers of aminophenol with the framework of density functional theory. Our calculated single core-hole ionization potentials were consistent with experiment and the previous theoretical values. Core-ionization energies via complex processes were also estimated. The difference of relaxation energy of two-site DCH (tsDCH) states can be visualized using Wagner plots. We found that the electron density of π orbitals on benzene ring are relaxed to core-vacancy sites at N,O tsDCH state.
<Keywords:> oft X-ray spectroscopy, double-core-hole state, X-ray free electron laser, DFT, Wagner plot
<URL:> https://www.jstage.jst.go.jp/article/jccj/14/6/14_2015-0057/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.14, 209-210, by J-STAGE]
<Title:> TD DFT法によるOHBAの吸光・発光スペクトルの理論的研究
<Author(s):> 新井　健文, 長岡　伸一, 長嶋　 雲兵, 寺前　裕之
<Corresponding author E-Mill:> teramae(at)gmail.com
<Abstract:> We have studied the first excited state of o-hydoroxybenzaldehyde with TD DFT calculations. We have attempted systematic calculations to select a proper functional to describe the correlation between the absorption and emission spectra and the Hammett’s σ values. The results with XAB95 functional are considered to be near the experimental results of the emission spectra.
<Keywords:> o-hydroxybenzaldehyde, OHBA, Time-dependent density functional theory, TDDFT, Proton transfer
<URL:> https://www.jstage.jst.go.jp/article/jccj/14/6/14_2015-0061/_article/-char/ja/