Kobayashi Yuka, Handa Hiroaki, Maeda Jin, Saigo Kazuhiko
Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Chirality. 2008 Mar;20(3-4):577-84. doi: 10.1002/chir.20530.
In order to clarify factor(s) determining the pattern of a hydrogen-bonding network in the diastereomeric salts of 1-arylethylamines (1) with enantiopure P-chiral acids, three kinds of enantiopure P-chiral alkylphenylphosphinothioic acids (3) were synthesized, and their chiral recognition abilities for racemic 1 were examined. The characteristics of the diastereomeric salt crystals of 1 with 3 were then studied on the basis of their X-ray crystallographic analyses. Statistical analysis on the molecular conformations observed in the diastereomeric salts with 3 as well as those with P-chiral O-alkyl arylphosphonothioic acids (2), which have a chemical structure similar to that of 3, and molecular orbital calculations for 2 and 3 in a gas phase revealed that the torsion angle between the aromatic plane and the P--O(alkoxy in 2) or P--C(alkyl in 3) plays an important role in determining the pattern of a hydrogen-bonding network in the diastereomeric salts, either a closed globular cluster or an infinite 2(1) column type. The calculations also indicated that there is a hydrogen-bonding-like interaction between the ammonium hydrogen atom of 1-arylethylammonium cations and the P--O(alkoxy) oxygen atom of phosphonothioate anions in the clusters.
为了阐明决定1-芳基乙胺（1）与对映体纯的P-手性酸的非对映体盐中氢键网络模式的因素，合成了三种对映体纯的P-手性烷基苯基硫代膦酸（3），并考察了它们对外消旋1的手性识别能力。然后基于X射线晶体学分析研究了1与3的非对映体盐晶体的特征。对与3以及与化学结构与3相似的P-手性O-烷基芳基硫代膦酸（2）形成的非对映体盐中观察到的分子构象进行统计分析，以及对2和3在气相中的分子轨道计算表明，芳环平面与P-O（2中的烷氧基）或P-C（3中的烷基）之间的扭转角在决定非对映体盐中氢键网络模式（封闭球状簇或无限2(1)柱型）方面起着重要作用。计算还表明，在簇中1-芳基乙铵阳离子的铵氢原子与硫代膦酸酯阴离子的P-O（烷氧基）氧原子之间存在类似氢键的相互作用。
