• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Adjacent Lone Pair (ALP) Effect: A Computational Approach for Its Origin
【24h】

Adjacent Lone Pair (ALP) Effect: A Computational Approach for Its Origin

机译：相邻孤对（ALP）效应：一种起源的计算方法

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The adjacent lone pair (ALP) effect is an experimental phenomenon in certain nitrogenous heterocyclic systems exhibiting the preference of the products with lone pairs separated over other isomers with lone pairs adjacent. A theoretical elucidation of the ALP effect requires the decomposition of intramolecular energy terms and the isolation of lone pair-lone pair interactions. Here we used the block-localized wavefunction (BLW) method within the ab initio valence bond (VB) theory to derive the strictly localized orbitals which are used to accommodate one-atom centered lone pairs and two-atom centered sigma or pi bonds. As such, interactions among electron pairs can be directly derived. Two-electron integrals between adjacent lone pairs do not support the view that the lone pair-lone pair repulsion is responsible for the ALP effect. Instead, the disabling of pi conjugation greatly diminishes the ALP effect, indicating that the reduction of pi conjugation in deprotonated forms with two s lone pairs adjacent is one of the major causes for the ALP effect. Further electrostatic potential analysis and intramolecular energy decomposition confirm that the other key factor is the favorable electrostatic attraction within the isomers with lone pairs separated.
机译：相邻孤对（ALP）效应是某些含氮杂环系统中的一种实验现象，表现出孤对分离的产物优先于孤对相邻的其他异构体。从理论上阐明ALP效应需要分解分子内能量项并分离孤对-孤对相互作用。在这里，我们从头计算价键（VB）理论中使用了块局部化的波动函数（BLW）方法，得出了严格定位的轨道，这些轨道用于容纳以一个原子为中心的孤对和以两个原子为中心的sigma或pi键。这样，可以直接导出电子对之间的相互作用。相邻孤对之间的两电子积分不支持这样的观点，即孤对-孤对排斥是造成ALP效应的原因。相反，禁用pi共轭可大大降低ALP效应，这表明具有两个相邻孤对的去质子化形式的pi共轭的减少是ALP效应的主要原因之一。进一步的静电势分析和分子内能量分解证实，另一个关键因素是具有分离的孤对的异构体内部的有利静电吸引。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号