Thiazyl halides, complexes

The thiazyl cation is used for the preparation of other S-N compounds (see Scheme 2). For example, the insertion reactions with S4N4 and SCI2 produce the S5N5+ (5) and C1SNSC1+ (21) cations respectively. Insertion of thia l cations into the metal-halogen bond of Re(CO)sX (X = Cl, Br) provides a route to thiazyl halide complexes. 

Monomeric thiazyl halides NSX (X = F, Cl Br) have been characterized in the gas phase, but oligomerization to cyclic species, e.g., (NSX)3 (X = F, Cl) and (NSF)4, occurs in the condensed phase (Section 8.7). These ligands can be stabilized, however, by coordination to a transition metal. The NSF complexes are conveniently prepared in SO2 (Eq. 1.6) The monomeric fluoride NSF is conveniently generated in situ by thermal decomposition of FC(0)NSF2 or Hg(NSp2)2 (Section 8.2). 

Monomeric thiazyl halides can be stabilized by coordination to transition metals and a large number of such complexes are known (Section 7.5). In addition, NSX monomers undergo several types of reactions that can be classified as follows (a) reactions involving the n-system of the N=S bond (b) reactions at the nitrogen centre (c) nucleophilic substitution reactions (d) halide abstraction, and (e) halide addition. Examples of each type of behaviour are illustrated below. 

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