Intramolecular S⋯S and S⋯O close contacts in 1,8-bis(phenylsulfanyl)naphthalene derivatives of different sulfur valence state: an X-ray study

Abstract

Four peri-substituted naphthalene derivatives, 1,8-bis(phenylsulfanyl)naphthalene (1), 1,8-bis[(2-methoxycarbonylphenyl)sulfanyl]naphthalene (2), bis[(2-methoxycarbonyl-phenyl)-sulfinyl]naphthalene (3) and bis[(2-methoxycarbonylphenyl)sulfonyl]naphthalene (4) with different valence states of sulfur were prepared and their molecular structures determined by X-ray diffraction. Data were collected on CAD-4 diffractometers with monochromated MoKα and CuKα radiations. Naphthalene ring torsions, aromatic ring orientations, S⋯S and S⋯O close contacts were analyzed and the controlling factors established. In both halves of the molecules, the naphthyl and phenyl rings assume axial–equatorial positions in bis-sulfides 1 and 2, and twist-axial positions in bis-sulfoxide 3 and bis-sulfone 4. The S⋯S distance was found to be 3.01, 3.18; 3.01 and 3.53Å, for 1, 2, 3 and 4, respectively. The equatorial S-phenyl rings in 2 and the steric crowd in 4 are unfavorable factors for S⋯S contacts. As expected, S(II)⋯O and S(IV)⋯O close contacts are formed in the equatorial and axial S-phenyl rings of 2 and 3, respectively, with 2.72, 2.73 and 2.77, 2.83Å distances. Steric repulsion in bis-sulfone 4 is moderated by two C(ar)–S(VI)⋯O(sulfonyl) type close contacts (2.89 and 3.02Å), which join the two halves of the molecule.