1.2.3.5- Dithiadiazolylium cation

Dithiadiazolylium cations (as the chloride salt) were first prepared in 1977 (77INCL143) from the reaction of thiazyl chloride 11 with organic nitriles. Thiazyl chloride 11 exists as a trimer 11a in the solid state (61AX562), but partial dissociation to the monomer lib occurs in the vapor phase (70IC1079) and in solution (88IC2749). 

In a separate example, the 4-phenyl-l,2,3,5-dithiadiazolium cation in the presence of [S3N3] gave 4-phenyl-1,2,3,5-dithiadiazolylium-l,3,5,2,4,6-trithiatriazinide 16. Ab initio calculations show that the ionic charges of the two rings are... 

In contrast, species with dithiadiazolylium rings in close proximity, e.g., [84][AsF6]2 and [85][AsF6]2, show strong intramolecular electron correlation and have two discrete, one-electron, reversible reductions to the radical cation and the diradical [92JCS(D)859]. 

Bond distances and angles are similar to those observed for the related phenyl- and phenylene-substituted compounds described previously (Sections V.A, XV, and XXII.C). The solvent molecule interacts weakly with the 1,2,3,5-dithiadiazolylium heterocyclic ring, but it does not appear to induce any significant structural perturbations. As with other 1,2,3,5- and 1,3,2,4-dithiadiazolylium salts, weak anion-cation interactions are seen between fluorine and both carbon and sulfur, but not between fluorine... 

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