Captodative Stabilization in Geminally Substituted Allylic Radicals Assessed by Means of the EPR-Spectral D Parameter of 1,3-Cyclopentanediyl Triplet Diradicals
作者:Waldemar Adam、Claudio M. Ortega Schulte
DOI:10.1002/ejoc.200300642
日期:2004.4
The EPR-spectral zero-field parameter D of low-temperature persistent triplet diradicals T was used to assess the electronic substituent effects in EA/ED and ED/ED geminally substituted allylic radicals. From these EPR data, the interaction parameter (ΔS) was calculated for a set of doubly functionalized radicals, which expresses the ability of the unpaired electron to interact either individually
低温持久性三线态双自由基 T 的 EPR 光谱零场参数 D 用于评估 EA/ED 和 ED/ED 孪位取代的烯丙基中的电子取代基效应。根据这些 EPR 数据,计算了一组双官能化自由基的相互作用参数 (ΔS),它表示未配对电子单独与官能团相互作用或同时以协同或拮抗方式相互作用的能力。我们表明 ED/ED 组合与奇电子相互作用,而 R2N/EA 和 MeO/EA 对显示出明显的俘获离域。与 MeO/EA 相比,MeS/EA 官能团仅表现出单个取代基的累加效应。这些结果在适当的电子转移型介体结构方面被合理化。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)