Journal of Computer Chemistry, Japan
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11 巻 , 3 号
選択された号の論文の7件中1~7を表示しています
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研究論文
  • Masato OSHIMA, Masaharu ITO, Shin-ya SUZUKI, Kazuhide MATSUMURA, Hiroh ...
    11 巻 (2012) 3 号 p. 125-130
    公開日: 2012/10/25
    [早期公開] 公開日: 2012/08/10
    ジャーナル フリー
    The calculations of a C–H bond activation were carried out with a two-layer ONIOM (MO:MM) method using DREIDING for the low layer and density functional theory (DFT) at the B3LYP level for the high layer. One of the calculated elementary reactions was that from (C5Me5)Ru(μ-CH2=CH2)(μ-H)2Ru(C5Me5) (4) to (C5Me5)Ru(μ-CH=CH2)(H)(μ-H)2Ru(C5Me5) (5) (eq 2) and the other was that from (C5Me5)Ru(C2H5)(μ-CH2=CH2)(μ-H)Ru (C5Me5) (6) to (C5Me5)Ru(C2H5)(μ-CH=CH2)(H)(μ-H)Ru(C5Me5) (7) (eq 3). All the optimized geometries were consistent with the intermediates in keeping with the phenomenon of "bimetallic activation" reaction where the two metal centers work concertedly in a reaction. The activation free energies of eqs 2 and 3 were 18.8 and 6.9 kcal/mol, respectively. The calculations of two types of C–H bond activation pathways that respectively contain eqs 2 and 3 were carried out. These results suggested that the pathway containing eq 3 was suitable.
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  • Shinsaku FUJITA
    11 巻 (2012) 3 号 p. 131-139
    公開日: 2012/10/25
    [早期公開] 公開日: 2012/09/25
    ジャーナル フリー
    On the basis of restricted subduced cycle indices with chirality fittingness (RSCI-CFs), the restricted-fixed-point-matrix (RFPM) method has been developed as a new method for the combinatorial enumeration of sterically hindered derivatives of a given skeleton. Such RSCI-CFs are derived from subduced cycle indices with chirality fittingness (SCI-CFs) defined in the unit-subduced-cycle-index (USCI) approach (S. Fujita, "Symmetry and Combinatorial Enumeration in Chemistry," Springer-Verlag (1991)). Thus, the SCI-CFs are combined with territory indicators to give territory discriminants, which are treated by considering a restriction condition that rejects the occupation of any adjacent sites, so as to generate RSCI-CFs. The resulting RSCI-CFs are used to evaluate marks (the numbers of fixed points) in place of the original SCI-CFs and combined with the fixed-point-matrix (FPM) method of the USCI approach to develop the RFPM method. The RFPV method based on RSCI-CFs is applied to enumeration of sterically hindered derivatives of dodecahedrane.
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  • Shinsaku FUJITA
    11 巻 (2012) 3 号 p. 140-148
    公開日: 2012/10/25
    [早期公開] 公開日: 2012/09/25
    ジャーナル フリー
    The restricted-partial-cycle-index (RPCI) method for combinatorial enumeration under the restriction of no adjacency of ligands has been developed as a restricted version of the partial-cycle-index (PCI) method of the unit-subduced-cycle-index (USCI) approach (S. Fujita, "Symmetry and Combinatorial Enumeration in Chemistry," Springer-Verlag (1991)). To take account of the restriction condition, (unrestricted) subduced cycle indices with chirality fittingness (SCI-CFs) of the USCI approach are converted into restricted subduced cycle indices with chirality fittingness (RSCI-CFs). Then, restricted partial cycle indices with chirality fittingness (RPCI-CFs) are derived from the RSCI-CFs, just as partial cycle indices with chirality fittingness (PCI-CFs) are derived from the SCI-CFs in the USCI approach. The resulting RPCI-CFs provide generating functions for restricted enumerations. The RPCI method using such RPCI-CFs is applied to enumeration of dodecahedrane derivatives under the restriction of no adjacency of ligands. Several enumerated derivatives are depicted and their symmetries are discussed to comprehend stereochemical properties such as pseudoasymmetry, sphericity, and prochirality.
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技術論文
  • 吉村 季織, 高柳 正夫
    11 巻 (2012) 3 号 p. 149-158
    公開日: 2012/10/25
    [早期公開] 公開日: 2012/10/16
    ジャーナル フリー
    近年,化学データを数学的・統計的手法により解析する「ケモメトリクス」が頻繁に用いられるようになってきた.しかし,日本の大学の化学教育の場ではほとんど取り上げられていない.ケモメトリクスや数値計算の専用ソフトウェアを使うことなく,現在最も普及しているソフトウェアのひとつであるMicrosoft Excel(Excel)の基本機能を用いてケモメトリクス計算を行うことができれば,多くの教育・研究機関で役立つものと思われる.シリーズ5回目は,スペクトルなどの観測データの前処理として用いられる平滑化と数値微分を取り扱う.平滑化や数値微分の代表的手法として最小二乗法を基にしたSavitzky Golay法(SG法)が広く知られている.我々はSG法と同原理の平滑化・数値微分法をExcel上で実行する方法を開発したので報告する.まず,SG法の畳み込み係数に相当する係数を求めるワークシートを作成した.さらにGauss関数を例に平滑化・数値微分を実行するワークシートを作成した.平滑化および数値微分値が,Gauss関数及びその導関数とよく一致していることを確認した.本法の平滑化・数値微分係数と,SG法の畳み込み係数を比較し,両者が等しいことを示した.また,畳み込み係数表の誤りも見出すことができた.これらの結果によって,本方法が平滑化・数値微分法として有用であると示された.
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