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

Abstract

The four oligosulfanes, bis(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)disulfane, C16H24Cl2O2S2, (III), 1,3-bis(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)trisulfane, C16H24Cl2O2S3, (V), 1,4-bis(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)tetrasulfane, C16H24Cl2O2S4, (VII), and 1,6-bis-(1-chloro-2,2,4,4-tetramethyl-3-oxocyclobutan-1-yl)hexasulfane, C16H24Cl2O2S6, (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 C2 symmetry. The molecule of the hexasulfane has crystallographic C2 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.