Electron Transfer Triggers Fast Dimer/Monomer Switching of Pyridinium and Quinolinium Cations
Electron Transfer Triggers Fast Dimer/Monomer Switching of Pyridinium and Quinolinium Cations
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DOI：
10.1021/jp211122n
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发表时间：
2012-01
影响因子：
3.7
通讯作者：
F. Teplý;Martina Čížková;P. Slavíček;V. Kolivoška;J. Tarábek;M. Hromadová;L. Pospíšil
中科院分区：
文献类型：
--
作者：
F. Teplý;Martina Čížková;P. Slavíček;V. Kolivoška;J. Tarábek;M. Hromadová;L. Pospíšil
含四元吡啶型氮原子的N-杂芳族阳离子具有良好的生物活性、荧光性质和氧化还原性质，具有广泛的应用前景。由这类化合物还原形成的自由基的反应性是关键。我们报道了四个含有吡啶、喹啉和苯并噻唑部分的新化合物的电子转移机理。吡啶和喹啉衍生物被一个电子还原产生自由基，这些自由基很快就形成σ-二聚体。二聚体可以通过氧化转化为母体阳离子，氧化在相当高的电位下进行。因此，可以通过施加适当的电极电位来可逆地切换二聚反应。相反，在苯并噻唑衍生物中，电子转移产生稳定的自由基，其中后续的二聚反应被完全阻止。通过对实验数据和理论模型的分析，确定了还原的吡啶和喹啉物种中的二聚中心。
N-Heteroaromatic cations with quaternary pyridine-type nitrogen atoms have a rich application potential due to their bioactivity, fluorescence, and redox properties. Reactivityof radicals formed by reduction of such compounds is of key importance. We report the electron transfer mechanismof four novel compounds containing pyridinium, quinolinium, and benzothiazolium moiety. The reduction of pyridinium and quinolinium derivatives by one electron yields radicals that very rapidly form σ-dimers. Dimers can be converted to parent cations by oxidation, which proceeds at considerably higher potentials. Hence the dimerization can be reversibly switched by application of the appropriate electrode potential. In contrast, in benzothiazolium derivative the electron transfer yields a stable radical in which the follow-up dimerization reaction is completely blocked. Analysis of experimental data as well as theoretical models led to the identification of dimerization sites in reduced pyridinium and quinolinium species....