Bis(2-chloroethyl)sulfane revisited: (ClH₄C₂)₂S⋯S(C₂H₄Cl) dimers by S⋯S interaction in the solid state

Abstract We synthesized bis(2-chloroethyl)sulfane, S(C 2 H 4 Cl) 2 , and showed its purity by various analytic methods. Its previously unknown crystal structure shows a peculiar intermolecular S⋯S interaction leading to (ClH 4 C 2 ) 2 S⋯S(C 2 H 4 Cl) 2 dimers. The S⋯S interaction could also be reproduced and investigated by quantum chemical calculations. As the C–C bonds have been observed unexpectedly short in the range from 1.505(2) to 1.509(2) Å, the chemical bonds within S(C 2 H 4 Cl) 2 have also been investigated quantum chemically. Intrinsic bonding orbitals (IBOs) showed that while the C–Cl bond is slightly polarized, the C–C and C–S bonds appear purely covalent, as expected. The electron density between the respective two C atoms is decreased by the attached Cl atom so that the two C atoms move closer to each other. High-resolution low-temperature Raman spectra of solid S(C 2 H 4 Cl) 2 are presented, and the bands are assigned with the aid of quantum chemical solid-state calculations.