The absorption spectra of non-substituted, 2,5-dimethyl-, 2,5-di-tert-butyl-, trimethyl-, tetramethyl-p-benzosemiquinone ions have been measured. In alkaline ethylene glycol fairly stable semiquinone ions were prepared by an oxidation of hydroquinones or by a reduction of quinones at room temperature. It is found that in visible or near ultra-violet region p-benzosemiquinone ions have three intense absorption bands due to π→π* allowed transitions in addition to a weak absorption in the region 450 ∼ 550 mμ presumably due to n → π* transition.
No takes yet. Share an insight, caveat, or question.
Harada et al. (1964) studied this question.
Synapse has enriched 3 closely related papers on similar clinical questions. Consider them for comparative context: