Crystal structure of bis-(o-nitrophenyl) disulphide

Abstract

The crystal and molecular structure of bis-(o-nitrophenyl) disulphide has been determined by three-dimensional X-ray diffraction techniques. Crystals are monoclinic with Z= 4 in a unit cell of dimensions a= 7·31, b= 23·03, c= 7·80 Å and β= 97·42°, space group P2₁/c. The S–S bond length is 2·045 Å and the average S–C distance is 1·796 Å, both indicating double-bond character. The intramolecular nearest-neighbour S ⋯ O(NO₂) distances are 2·636 and 2·588 Å, significantly less than the sum of the van der Waals radii for S and O, indicating nonbonded attractions. The angles between the plane of each phenyl ring and its nitro-group are 18·6 and 7·0° and the respective C–N distances are 1·476 and 1·425 Å. The shorter of the S ⋯ O contacts is associated with the shorter C–N distance and the more nearly coplanar nitrophenyl groups. These effects combine to make one of the S–C–C–N–O fragments a more effective π-system than the other and suggest that the significant S ⋯ O interaction in this system is consistent with increased stabilization of higher electron-density in the nitro-group. Except for the one short C–N distance the bond lengths and angles generally are not very different from those found in the para-isomer.

Molecular packing produces no unusually close intermolecular contacts. The final R for 826 independent, non-zero reflections is 6·2%.