1.2- Dithiins structure determination

Dithiins and It4-Di elenins.—1,4-Dithiins (36) are among the photolysis products of biaryl- and benzo-l,2,3-thiadiazoles. The postulated intermediate biradicals (35) dimerize in the direction shown. Thermolysis of cycloalkeno-l,2,3-selenadiazoles produces 1,4-diselenins (37) together with cycloalkynes. A structure determination of 2,5-diphenyl-l,4-dithiin 1-oxide reveals a boat-shaped configuration (Figure) with the sulphur... 

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 +. 

Many crystal structures of host compounds or solvate compounds with 1,4-dioxane as well as a wide range of organic structures bearing a 1,4-dioxin, 1,4-oxathiin, or 1,4-dithiin core have been determined by single crystal X-ray diffraction. 

Syn- and A-bis-benzothienyl-l,4-diselenins 193 and 194 have been prepared by metallation sequences (Equations 50, 51). The crystal structures of 193 and 194 were determined and compared with the corresponding dithiins <2006CL422>. These fused diselenins exhibit unusual redox properties, being less stable in the oxidized form than the corresponding dithiins. 

Dithiins.— The cyclic structure of 1,2-dithiins has been further substantiated by a determination of the heat of formation of 3,6-diphenyl-l,2-dithiin. ... 

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