The Thionyl Imide Anion

Alkali-metal thionylimides are prepared by the reaction of Me3SiNSO with the appropriate alkali-metal tert-butoxide in THF.112 The more soluble salt [(Me2N)3S][NSO] has also been reported.113 

The bent [NSO]- anion (36) in the tetramethylammonium salt [Me4N][NSO] has approximately equal S-N and S-O bond lengths of 1.43 and 1.44 A, respectively, and a bond angle NSO of ca. 127°.114 Salts of the [NSO]- anion can be used for the synthesis of both transition-metal and main group element thionyl imides by metathetical reactions.70 

---

A variety of complexes of the thionyl imide anion [NSO] with both early and late transition-metal complexes have been prepared and structurally characterized. Since both ionic and covalent derivatives of this anion are readily prepared, e.g., K[NSO], McsMNSO (M = Si, Sn) or Hg(NSO)2, metathetical reactions of these reagents with transition-metal halide complexes represent the most general synthetic method for the preparation of these complexes (Eq. 7.10 and 7.11). ... 

---