Observation of intramolecular dimer radical anion of 1,1-diarylmethanols bearing electron withdrawing groups at room temperature
作者:Nobuyuki Ichinose、Junpei Hobo、Sachiko Tojo、Tetsuro Majima
DOI:10.1016/s0009-2614(00)01089-7
日期:2000.11
Transient absorption measurement of radical anions of 1,1-diarylmethanols bearing electron-withdrawing groups in dimethyl-formamide at room temperature has revealed that symmetric compounds form intramolecular dimer radical anions as an intermediate of their reductive C-O bond dissociation giving diarylmethyl radicals. The dimer radical. anions showed an absorption band in the near infrared region (NIR) (1000-1600 nm) characteristic to their charge resonance (CR) properties. On the contrary to 1, 1-diarylmethanols, corresponding radical anion of 1,3-diarylpropan-1-ol showed no CR band. It is suggested that formation of dimer radical anions is energetically favorable for diaryl compounds with one-atom spacer but unfavorable for them with three-atom spacer being different From the n = 3 rule for the favorable formation of intramolecular excimers. (C) 2000 Elsevier Science B.V. All rights reserved.