2,3,7,8-Tetramethoxythianthrene. A novel ground state triplet dication, the neutral photogenerated triplet, and the radical cation

Ira B. Goldberg, Harry R. Crowe, George S. Wilson, Richard S. Glass

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The dication of 2,3,7,8-tetramethoxythianthrene was studied in solid nitromethane at 77 K by computer-controlled electron spin resonance. The Δm = 2 transition was observed, yielding a value of D* = 0.106 cm-1. For comparison the values of D* for thianthrene and 2,3,7,8-tetramethoxythianthrene photogenerated triplets determined were 0.135 and 0.121 cm-1, respectively. Lifetimes of these triplet states were also determined. Frozen solutions of the tetramethoxythianthrene dication exhibited a very broad Δm = 1 signal that could not be resolved into components D and E of the dipolar tensor. The free energy separation between the triplet and singlet states is between 90 and 190 cm-1. The ESR spectrum of the cation was redetermined. The hyperfine splittings at 23°C in nitromethane were aS = 7.30 ± 0.05 G, aH(OCH3) = 0.28 ± 0.02 G, and aH(1,4,6,9) = 0.87 ± 0.04 G, and the g factor is 2.00732 ± 0.00006.

Original languageEnglish (US)
Pages (from-to)988-992
Number of pages5
JournalJournal of physical chemistry
Issue number9
StatePublished - Jan 1 1976


ASJC Scopus subject areas

  • Engineering(all)
  • Physical and Theoretical Chemistry

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