Dithiins crystallography

Figure 17. 1,4-Dithiin 21 and the molecular structure of its radical-cation salt 2f+SbF6 determined by X-ray crystallography. The observed lengths (A) of Cl-S and C1-C2 in 2f+SbF6 are 1.72(1) and 1.31(2) to be compared with 1.324(3) and 1.760(2) determined for neutral 21, respectively. Also shown is the thianthrene radical cation 23 +. 

In total contrast, the unusual dithiin 25 shows a marked tendency for the insertion of sulfur with the formation of the diborneo-l,2,3-trithiepine 120. The structure of 120 was elucidated by X-ray crystallography and the seven-membered ring interconversion studied by dynamic H NMR (AG = 13.0kcalmoP ) <1995T13247>. 

From Other Sulphur Heterocycles. The diazo-ketone (24), prepared from 27f-thiopyran-3(6//) Oi c and phenyl azide, yields (25) upon heating, which apparently is the stable tautomer of 3-hydroxy-4-phenylaminomethylthiophen, and (26). The structures of both compounds were proven by 2f-ray crystallography. The thermal and photochemical reactions of 1,4-dithiin sulphoxides... 

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