Charge delocalization from cationic substituents into phenanthrene: variation in response among regioisomeric carbocations and carboxonium ions
作者:Kenneth K. Laali、Sandro Hollenstein
DOI:10.1039/a707423i
日期:——
In an effort to assess charge delocalization and stabilities, a series of regioisomeric PAH–C+R2 carbocations (PAH = phenanthrene; R = Me, Ph) were generated from their alcohols by ionization with FSO3H/SO2ClF. Model carboxonium ions were also generated by O-protonation of the isomeric acetyl- and benzoyl-phenanthrenes with FSO3H/SO2ClF. The delocalization paths and the arenium ion character in the resulting carbocations and carboxonium ions are evaluated via low temperature NMR studies; conformational aspects in the carboxonium ions are also addressed. The resulting cations may serve as models for epoxide ring opening in biologically active dihydro diols of several classes of PAHs for which the diol epoxide activation path is believed to be significant in cancer induction.
为了评估电荷的去局域化和稳定性,生成了一系列区域异构的PAH–C+R2碳正离子(PAH = 苯并蒽;R = 甲基,苯基),通过用FSO3H/SO2ClF对其醇进行电离。模型羧鎓离子则通过对异构的乙酰-和苯甲酰-苯并蒽进行O质子化而生成,同样使用FSO3H/SO2ClF。通过低温NMR研究评估了生成的碳正离子和羧鎓离子的去局域化路径和芳香离子特征;还讨论了羧鎓离子中的构象方面。这些生成的阳离子可以作为多种PAH类生物活性二醇中环氧化物开环反应的模型,这些二醇的环氧化物激活路径被认为在癌症诱导中具有重要意义。