Thianthrenes theoretical calculations

G calculations on 2,3,7,8-tetrachlorooxanthrene have been carried out and the authors found that a near planar structure is favored for this compound <88JOC547l). Thianthrene has been the subject of many theoretical studies. Molecular mechanics calculations predict an inversion barrier of 4.6 kcal mol by the MM method <85JA5323), and a dihedral angle of 150° or 125° by the semiempirical PM3 calculational method <930M77S) or hy the 4-31G basis set <90JST(204)4i), respectively. 

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