Direct insertion of a nitrogen atom into the S–S bond of a 1,2,3,5- dithiadiazole ring in a direct current nitrogen glow discharge, and X-ray crystal structure of 4-methyl-1,2,3,5-dithiadiazole

Abstract

Dimeric aryldithiadiazoles (R[graphic omitted])₂(R = Ph or p-ClC₆H₄,) were treated with atomic nitrogen, generated in a cool direct current plasma, to form the corresponding dithiatriazine dimers by nitrogen insertion into the S–S bonds; alkyl derivatives (R = Me, Pr, or Bu^t) gave polymeric products. Dithiadiazolylium salts [R[graphic omitted]]⁺ X^–(R = Ph or p-ClC₆H₄; X = I, Br, CN, or S₃N₃) also reacted with nitrogen plasma to give high yields of the respective dithiatriazine (RCN₃S₂)₂. Structural criteria for the reaction are discussed. The crystalline methyldithiadiazole contains planar [graphic omitted] rings with S–S 2.076(2), S–N 1.636(3), C–N 1.324(5)Å, N–S–S 94.5(1), C–N–S 114.5(3), and N–C–N 122.2(4)°(all average values). Within the dimer unit the parallel monomer rings are linked via one weak S ⋯ S bond (3.10 Å). The crystals are triclinic, space group P, with a= 11.296(1), b= 12.498(1), c= 14.647(2)Å, α= 72.06(1), β= 77.85(1), γ= 77.30(1)°, and Z= 8.