4-arylflavan-3-ols as proanthocyanidin models: absolute configuration via density functional calculation of electronic circular dichroism.
4-arylflavan-3-ols as proanthocyanidin models: absolute configuration via density functional calculation of electronic circular dichroism.
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DOI：
10.1021/np900645c
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发表时间：
2010-03-26
影响因子：
5.1
通讯作者：
Ferreira, Daneel
中科院分区：
文献类型：
--
作者：
Ding, Yuanqing;Li, Xing-Cong;Ferreira, Daneel
采用密度泛函理论/B3 LYP方法对4-芳基黄烷-3-醇及其酚甲醚3-O-乙酸酯的构象进行了优化。主要构象的电子圆二色性光谱已使用含时密度泛函理论计算验证经验芳香族象限规则适用于这类化合物的绝对构型的分配。适度的6- 31 G * 基组足以产生合理的光谱。计算的Cotton效应在220-240 nm之间，对于C-4绝对构型的分配至关重要，是由涉及空间上接近的芳香A-环和4-芳基部分的π-电子的分子轨道的电子跃迁引起的。这种柯顿效应的符号由4-芳基取代基的方向决定：负和正的柯顿效应分别与4个α-和4个β-芳基取代基相关。
Density functional theory/B3LYP has been employed to optimize the conformations of selected 4-arylflavan-3-ols and their phenolic methyl ether 3-O-acetates. The electronic circular dichroism spectra of the major conformers have been calculated using time-dependent density functional theory to validate the empirical aromatic quadrant rule applied to the assignment of the absolute configuration of this class of compounds. The modest 6–31G* basis set was sufficient to produce reasonable spectra. The calculated Cotton effects between 220–240 nm, crucial for the assignment of the C-4 absolute configuration, results from electronic transitions of the molecular orbitals involving the π-electrons of the spatially close aromatic A-ring and 4-aryl moieties. The sign of this Cotton effect is determined by the orientation of the 4-aryl substituent: the negative and positive Cotton effects are associated with 4α-and 4β-aryl substituents, respectively.
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影响因子：
2.9
作者：
Diedrich, C;Grimme, S
通讯作者：
Grimme, S
DOI：
10.1039/p29930000799
发表时间：
1993-05-01
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
影响因子：
--
作者：
KLAMT, A;SCHUURMANN, G
通讯作者：
SCHUURMANN, G
DOI：
10.1039/c39780000698
发表时间：
1978-01-01
影响因子：
--
作者：
BOTHA, JJ;FERREIRA, D;ROUX, DG
通讯作者：
ROUX, DG
影响因子：
5.1
作者：
Ding, Yuanqing;Li, Xing-Cong;Ferreira, Daneel
通讯作者：
Ferreira, Daneel
影响因子：
3.6
作者：
Stephens, P. J.;Devlin, F. J.;Cosimelli, B.
通讯作者：
Cosimelli, B.