Aurated Selenonium and Telluronium Ions

Polychalcogen Dications. The first disulfonium dication derived from 

Furukawa and coworkers have also studied dications with a Se-Se unit. Dication 115 was generated by two-electron oxidation with NO1PF6 [Eq. (4.95)].317 Computational studies of the isomeric structures have led to the same conclusions as already discussed above for disulfonium dication 112. The analogous ditellurium dication (BI i and PI fi salts) has also been prepared.318 

Minkwitz et al.319 have obtained dications 116 in the reactions of Me2SH+ and Me2SSH+ with SC12 and S2C12, respectively, and reported spectroscopic characterization (IR, X-ray, and lH and 13C NMR). 

Other dications with three chalcogen atoms have also been studied.316 When the tris-selenide precursor was oxidized with NO+PFg, the twin-chair conformer changed to the more rigid twin boat conformer 119 [Eq. (4.96)]. 321 This was evidenced 

The X-ray structure of dication 120 exhibits features very similar to those of the analogous dication 118 (R = Ph).322 Treatment of bis(4-methylphenyl)telluride with NO 1 BI i or Tf02 has afforded dication 121 with NO or O2 as the oxygen source.326 The ions are dimeric in the solid state and the anions interact with the Te atoms through their O atoms. The Te—O contacts are considerably shorter than the sum of the van der Waals radii of the two atoms (2.64—2.98 A versus 3.60 A). The Te atoms have pseudo-octahedral geometry. 

---