Zur Protonierung und Methylierung des 1, 1-Dicyanoethylen-2, 2-dithiolat Dianions: Präparative und strukturelle Untersuchungen

Protonation and Methylation of 1, 1-Dicyanoethylene-2, 2-dithiolate Dianion. Preparative and Structural Investigations Protonation of alkaline metal salts of [S₂C = C(CN)₂]^2? ( I ) in water yields a product of composition H₂S₂C₄N₂ ( II ). The species has to be formulated as dimere and crystallizes with two moles DMSO from DMSO solution with space group C2/c and a = 20.611(3), b = 4.800(1), c = 20.638(3) Å, β = 103.3(1)°, Z = 4. The X-ray structural analysis shows II to be a centrosymmetric 1, 3-Dithiacyclobutane system. On methylation of I with CH₃I in the molar ratio 1:1, the monomethylated anion III can be isolated as AsPh₄ salt. The compound crystallizes in the monoclinic space group P2₁/c, with a = 23.632(2), b = 14.304(1), c = 7.989(1) Å, β = 100.1(8)° and Z = 4. There are nearly planar anions [MeS(S)C?C(CN)₂]^? with an anti-conformation of the MeS group.