Contrasting Behavior in the Reduction of 1,2-Acenaphthylenedione and 1,2-Aceanthrylenedione. Two Types of Reversible Dimerization of Anion Radicals
Contrasting Behavior in the Reduction of 1,2-Acenaphthylenedione and 1,2-Aceanthrylenedione. Two Types of Reversible Dimerization of Anion Radicals
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DOI：
10.1021/jp809667f
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发表时间：
2009-01
影响因子：
3.7
通讯作者：
N. Macías-Ruvalcaba;Greg A. N. Felton;Dennis H. Evans
中科院分区：
文献类型：
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作者：
N. Macías-Ruvalcaba;Greg A. N. Felton;Dennis H. Evans
伏安和光谱研究表明，1的阴离子自由基形成π-二聚体，而2的阴离子自由基形成σ-二聚体。这两个二聚体的形成是可逆的。这些结论是建立在循环伏安分析的基础上的，对于阴离子自由基1，在光谱电化学监测下，在995 nm处出现了一个长波吸收带。通过与已知的形成π-二聚体(2，3-二氯-5，6-二氰基-1，4-苯二酚的阴离子自由基，3)和σ-二聚体(9-乙酰基菲的阴离子自由基，4)所得结果的比较，也获得了载体。通过密度泛函理论计算，确定了2的σ-二聚体的二聚化位置，并发现其位置与已知的4的位置相似。
Voltammetric and spectroscopic studies of 1,2-acenaphthylenedione, 1, and 1,2-aceanthrylenedione, 2, have shown that the anion radicals of 1 form a π-dimer whereas a σ-dimer is found with 2. The formation of both dimers is seen to be reversible. These conclusions are based on analysis of the cyclic voltammograms and, for the anion radical of 1, the appearance of a long wavelength absorption band at 995 nm as observed by spectroelectrochemical monitoring. Support was also obtained by comparison of the results with those obtained with systems known to form π-dimers (anion radical of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, 3) and σ-dimers (anion radical of 9-acetylanthracene, 4). The site of dimerization in the σ-dimer of 2 has been assigned through DFT calculations and found to be at a position analogous to that which is known for 4.