Four bis(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)oligosulfanes

Acta Crystallogr C. 2002 Aug;58(Pt 8):o480-4. doi: 10.1107/s0108270102011319. Epub 2002 Jul 20.

Abstract

The four oligosulfanes, bis(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)disulfane, C(16)H(24)Cl(2)O(2)S(2), (III), 1,3-bis(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)trisulfane, C(16)H(24)Cl(2)O(2)S(3), (V), 1,4-bis(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)tetrasulfane, C(16)H(24)Cl(2)O(2)S(4), (VII), and 1,6-bis(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)hexasulfane, C(16)H(24)Cl(2)O(2)S(6), (VIII), all have similar geometric parameters, with the C-C bond lengths involving the chloro-substituted cyclobutanyl C atom being elongated to about 1.59 A. There are two molecules in the asymmetric units of the tri- and tetrasulfanes, and the molecules in the latter compound have local C(2) symmetry. The molecule of the hexasulfane has crystallographic C(2) symmetry. Most of the cyclobutanyl rings are not perfectly planar and have slight but varying degrees of distortion towards a flattened tetrahedron. The polysulfane chain in each structure has a helical conformation, with each additional S atom in the chain adding approximately one quarter of a turn to the helix.