CRYSTAL STRUCTURE OF ALPHA-BIS(P-NITROPHENYL) DISULFIDE

The crystal and molecular structure of bis(p-nitrophenyl) disulfide has been determined by three-dimensional single-crystal X-ray diffraction techniques. The compound crystallizes in the monoclinic system, space group C2/c, with four molecules at special positions in a unit cell having the following dimensions: a = 7.30 Å (ó = 0.03), b = 14.18 Å (ó = 0.02), c = 12.76 Å (ó = 0.04), and β = 95.0° (ó = 0.5°). The molecule consists of two identical halves related by a twofold axis passing midway between the two sulfur atoms. The S-C bond length is 1.767 Å (ó = 0.010), the average N-O length is 1.207 Å (ó = 0.013), and the O-N-O angle is 124° (ó = 1°). The dihedral angle about the S-S bond is 72° (ó = 2°), and the angle between the plane of the phenyl ring and the plane of the nitro group is 8.2° (ó = 0.5°). The length of the C-N bond is 1.488 Å (ó = 0.013), which implies that the amount of resonance between the benzene ring and the -NO2, fragment is negligible. This result may be accounted for by repulsive forces between the oxygens of the nitro group and the substituted carbon of the benzene ring. The S-S distance, 2.019 Å (ó = 0.005), implies some σ character in this bond. This distance, the sulfur valency angle, and the dihedral angle about the -S-S- fragment closely resemble those found in orthorhombic sulfur. The molecular packing produces no unusually close molecular contacts despite the fact that short O … S contacts are known to occur. The final discrepancy factor for 597 independent, nonzero, reflections is R(F) = 10.1%. © 1969, American Chemical Society. All rights reserved.