Thionyl imide

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). ... 

Salts of the [NSO] anion can be used for the synthesis of both transition-metal and main group element thionyl imides by metathetical reactions, e.g., Cp2Ti(NSO)2 and Ph3, .As(NSO)x (x = 1,2), respectively (Section 7.6). 

Thionyl imide, HNSO, is a thermally unstable gas, which polymerizes readily. It can be prepared by the reaction of thionyl chloride with ammonia in the gas phase. Organic derivatives RNSO have higher thermal stability, especially when R = Ar. The typical synthesis involves the reaction of a primary amine or, preferably, a silylated amine with thionyl chloride. A recent example is the preparation of FcNSO (Fc = ferrocenyl) shown in Eq. 9.8. In common with other thionylimines, FcNSO readily undergoes SO2 elimination in the presence of a base, e.g., KO Bu, to give the corresponding sulfur diimide FcNSNFc. 

Potassium thionyl imide, K[NSO], is readily prepared from MesSiNSO and potassium t-butoxide in THF. Sodium, rubidium, and cesium salts are synthesized in a similar maimer. The more soluble (Me2N)3S+ salt has also been prepared (equation 18). ... 

Monomeric thionyl imide polymerizes very rapidly. Even at above — 60° a yellow solid separates from the liquid which, with further warming becomes glass-clear yellow-brown, red, and finally brown. The brown polymer, which does not dissolve in organic solvents, is found from the infrared spectrum to contain NH groups 18), so that Formula (XLIX) proposed by Schenk appears to be established. 

The red solid compound HOSN may be isolated after evaporating the solvent. It is not, however, very stable and readily goes over into the brown polymer (XLIX). The red compound, which is monomeric in organic solvents, is an isomer of Schenk s thionyl imide. It polymerizes so readily that only chemical methods have hitherto been applied successfully in establishing the structure as (La) (18). 

Starting from imidosulfinamido (LII), the ammonolysis product of red HOSN, it is possible to obtain a further isomer of thionyl imide. Thus, when hydrogen chloride is condensed on to (LII) a yellow solution results... 

Finally, yet a fifth isomer of thionyl imide may be obtained in quite another way. Fluck and Becke-Goehring (S3) started with tetrasulfur tetra-imide (XIII) and oxidized it by heating with air at 110-120°. Among the products was the solid red tetramer of thionyl imide (LIV) which was solu-... 

The ammonium salt of thionyl imide, NH4(OSN), is transformed in a few hours at room temperature into imidosulfinamide (LII), with evolution of ammonia ... 

The imide from which the salt (LVI) is derived is the oxygen analog of the imide corresponding to the silver salt (XLVII). Its probable mode of formation entails initially the loss of ammonia and HOSN from two molecules of HN (SONH2)2. The resulting trimeric thionyl imide then tends to form its anhydride... 

H. G. Heal, The Inorgantc Heterocydtc Chemistry of Sulfur, Nitrogen and Phosphorus, Academic Press, London, 1980. This book has chapters on the cyclic oligomers formed by thiazyl halides, NSX sulfanuric halides, [NS(0)X] and thionyl imide, HNSO. 

Fig. 182. Preparation of thionyl imide. ft) Bodenstein valve G) needle valve condensation trap m ) manometer r) reaction vessel Sj, Sg) flowmeters ...

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