Preparation, Crystal Structure, and Spectroscopic Characterization of [(Se₂SN₂)Cl]₂

The reaction of [(Me₃Si)₂N]₂S with an equimolar amount of SeCl₄ in dioxane at 50 °C affords [(Se₂SN₂)Cl]₂ (1) in excellent yield. Crystals of 1 are orthorhombic, space group Pbca, with a = 8.5721(7) Å, b = 7.8336(6) Å, c = 15.228(1) Å, and Z = 8. The crystal structure contains two planar Se₂SN₂^•+ rings which are linked by intermolecular Se···Se interactions [d(Se−Se) = 3.0690(7) Å]. The EI mass spectrum shows Se₂SN₂^•+ as the fragment of highest mass. Both the ¹⁴N and ⁷⁷Se NMR spectra show a single resonance (−52 and 1394 ppm, respectively). The solid [(Se₂SN₂)Cl]₂ gives a strong ESR signal indicating the presence of a Se₂SN₂^•+ radical. The Raman spectrum was assigned through normal coordinate treatment involving a general valence force field. The vibrational analysis yielded a good agreement between the observed and calculated wavenumbers.