Single-Step versus Stepwise Two-Electron Reduction of Polyarylpyridiniums: Insights from the Steric Switching of Redox Potential Compression
作者:Jérôme Fortage、Cyril Peltier、Christian Perruchot、Yohei Takemoto、Yoshio Teki、Fethi Bedioui、Valérie Marvaud、Grégory Dupeyre、Lubomír Pospísil、Carlo Adamo、Magdaléna Hromadová、Ilaria Ciofini、Philippe P. Lainé
DOI:10.1021/ja210024y
日期:2012.2.8
1'-dipyridinium isomer (so-called "head-to-tail" isomer) undergoes two electron transfers at apparently the same potential (single-step reduction). A combined theoretical and experimental study has been undertaken to establish that the latter electrochemical behavior, also observed for other polyarylpyridinium electrophores, is due to potential compression originating in a large structural rearrangement
与通过两次单电子转移(逐步还原)还原的 4,4'-双吡啶鎓(即原型甲基紫精)相反,4,1'-双吡啶鎓异构体(所谓的“头对尾”异构体) ) 在明显相同的电位下经历两次电子转移(单步还原)。已经进行了一项理论和实验相结合的研究,以确定后一种电化学行为,在其他聚芳基吡啶鎓电泳中也观察到,是由于源自大结构重排的潜在压缩。制备了三个系列的支化膨胀吡啶鎓(EP):N-芳基-2,4,6-三苯基吡啶鎓(Ar-TP),N-芳基-2,3,4,5,6-五苯基吡啶鎓(Ar-XP),和 N-芳基-3,5-二甲基-2,4,6-三苯基吡啶鎓(Ar-DMTP)。分子内空间应变通过 N-吡啶基芳基 (Ar) 苯基 (Ph)、4-吡啶基 (Py) 和 4-吡啶鎓 (qPy) 及其庞大的 3,5- 二甲基对应物、二甲苯基 (Xy)、lutidyl (Lu) 和 lutidylium (qLu),分别。将二茂铁亚基作为内部氧化还原参考共价附加到代表性电泳,以计算以