Complexes of the and 2-Anions

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).  

Transition-metal complexes of the thionylimide anion exhibit characteristic vibrations in the regions 1260-1120, 1090-1010 and 630-515 cm , which are assigned to Oas(NSO), Os(NSO) and 5(NSO), respectively. X-ray structural data for several M-NSO complexes reveal N-S and S-O bond lengths of ca. 1.46 0.04 A indicative of double bond character in both of these bonds. 

Complexes in which two metal centres are linked by one or two [NSN] ligands, e.g., [Na(15-crown-5)]2[F5Mo( -NSN)MoF5] and Cp2Zr( -NSN)2ZrCp2, are known. The cyclic zirconium system is prepared by a metathetical reaction (Eq. 7.14). However, the formation of polymers in which metal centres are linked by NSN units has not been achieved. 

Woollins, The Preparation and Stmeture of Metalla-sulfur/selenium Nitrogen Complexes and Cages, in R. Steudel (ed.) The Chemistry of Inorganic Heterocycles, Elsevier, pp. 349-372 (1992). 

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