作者:Sachiko Tojo、Mamoru Fujitsuka、Tetsuro Majima
DOI:10.1021/jo1003949
日期:2010.6.4
An acyclic 1,4-distonic diner radical cation (DAE(2)(center dot+)) was generated from the dimerization of 1,1-bis(4-methoxyphenyl)ethylene radical cation (DAE(center dot+)) with the neutral molecule (DAE) in solution. The absorption spectrum of DAE(2)(center dot+) shows bimodal absorption bands with peaks at 350 and 500 nm corresponding to the 1,1-bis(4-methoxyphenyl)ethyl radical (An(2)C(center dot)CH(3)) and 1,1-bis(4-methoxyphenyl)ethyl cation (An(2)C(+)CH(3)), respectively. Therefore, DAE(2)(center dot+) 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 DAE(2)(center dot+) were observed at 77 K. showing that the excitation energy is localized on the radical or cation site of DAE, in the excited state. The interaction between radical and cation sites of DAE(2)(center dot+) 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.