The different electronic natures displayed by the alkylthio groups in simple and higher conjugated aniline systems
作者:Chien-Chung Han、R. Balakumar、D. Thirumalai、Ming-Tsu Chung
DOI:10.1039/b609506b
日期:——
Systematic studies based on 1H NMR and 13C NMR indicated that the alkylthio group behaves as a weak electron-withdrawing group in a simple aniline system like 2-butylthioaniline, while the same alkylthio group clearly acted as a resonance electron-donating group in higher conjugated aniline trimer systems, like butylthio-substituted PDA (mono-PDA) and dibutylthio-substituted PDA (2,6-diPDA). The formation of 2,6-diPDA as the major byproduct during the preparation of mono-PDA from PDI and butane-1-thiol provided additional support for the resonance electron donating nature of the butylthio group in these aniline trimer systems. Furthermore, CV studies also clearly indicated that the redox potential E°
(vs. SCE) of the aniline trimer systems decreased with the increase in the number of butylthio groups, further confirming the electron-donating nature of the butylthio group in these higher conjugated trimer systems.
基于 1H NMR 和 13C NMR 的系统研究表明,烷硫基在简单的苯胺体系(如 2-丁硫基苯胺)中表现为弱的夺电子基团,而在较高的共轭苯胺三聚体系(如丁硫基取代的 PDA(单 PDA)和二丁基硫基取代的 PDA(2,6-二 PDA))中,相同的烷硫基则明显表现为共振电子捐赠基团。在用 PDI 和丁烷-1-硫醇制备单 PDA 的过程中形成的主要副产品 2,6-二 PDA 进一步证明了丁硫基在这些苯胺三聚物体系中的共振电子捐赠性质。此外,CV 研究还清楚地表明,随着丁硫基数量的增加,苯胺三聚物体系的氧化还原电位 E°(相对于 SCE)也在降低,这进一步证实了丁硫基在这些高级共轭三聚物体系中的电子奉献性质。