The Crystal and Molecular Structure of 3,4-Dimethyl-2,5-diphenyl-3,4-dihydro-3a-thia-1,3,4,6-tetraazapentalene

The crystal structure of 3,4-dimethyl-2,5-diphenyl-3,4-dihydro-3a-thia-1,3,4,6-tetraazapentalene has been determined by the X-ray method. The crystals are orthorhombic, space group Pbcn, a=14.533(4), b=9.285(3), c=11.305(2) Å, V=1525.4(6) Å3, Z=4, Dx=1.343 Mg m−3. The final R value is 0.060 for 1107 reflections. The molecule has an exact C2 symmetry, with the central S–C bond coincident with the 2-fold axis of the crystal symmetry. The length of 1.904 Å of the two equivalent S–N bonds indicates that the molecule is a tetraaza analogue of the thiathiophthenes. The length of this S–N bond is 9% longer than the N–S single bond and significantly less than the sum of the van der Waals radii.