Site-Selective Bimodal Absorption and Emission of Distonic Radical Cation
Site-Selective Bimodal Absorption and Emission of Distonic Radical Cation
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异张力自由基阳离子的位点选择性双峰吸收和发射
DOI：
10.1021/jo1003949
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
T. Majima
中科院分区：
文献类型：
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作者：
S. Tojo;M. Fujitsuka;T. Majima
1，1-二（4-甲氧基苯基）乙烯自由基阳离子（DAE·+）与中性分子（DAE）在溶液中发生二聚反应，生成无环的1，4-二聚体自由基阳离子（DAE 2·+）。DAE 2·+的吸收光谱显示双峰吸收带，其峰位于350和500 nm处，分别对应于1，1-双（4-甲氧基苯基）乙基自由基（An 2C·CH 3）和1，1-双（4-甲氧基苯基）乙基阳离子（An 2C + CH 3）。因此，处于基态的DAE 2·+的自旋和正电荷分别位于1-和4-位置。在77 K下观察到DAE 2·+的自由基和阳离子位选择性激发的双峰特征发射，表明激发能集中在激发态的自由基或阳离子位上.根据稳态光谱和瞬态吸收测量以及理论计算，讨论了DAE ~（2·+）基态和激发态自由基与阳离子中心之间的相互作用。
An acyclic 1,4-distonic dimer radical cation (DAE2•+) was generated from the dimerization of 1,1-bis(4-methoxyphenyl)ethylene radical cation (DAE•+) with the neutral molecule (DAE) in solution. The absorption spectrum of DAE2•+shows bimodal absorption bands with peaks at 350 and 500 nm corresponding to the 1,1-bis(4-methoxyphenyl)ethyl radical (An2C•CH3) and 1,1-bis(4-methoxyphenyl)ethyl cation (An2C+CH3), respectively. Therefore, DAE2•+in the ground state has the spin and positive charge localized on the 1- and 4-positions, respectively. The bimodal characteristic emissions by the site-selective excitation of radical and cation sites of DAE2•+were observed at 77 K, showing that the excitation energy is localized on the radical or cation site of DAE2•+in the excited state. The interaction between radical and cation sites of DAE2•+in the ground and excited states are discussed on the basis of the steady-state spectroscopic and transient absorption measurements, as well as theoretical calculations.