Thiazyl halides

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. 

The aromaticity of such inorganic ring systems as borazine, the phosphonitrilic halides (69), and the thiazyl halides (70) has been studied extensively from a theoretical viewpoint. ... 

Thiazyl halide monomers undergo a variety of reactions that can be classified under the general headings (a) reactions involving the 7i-system of the N = S triple bond, (b) nucleophilic substitution, (c) halide abstraction, and (d) halide addition. The cycloaddition of NSF with hexafluoro-1,3-butadiene provides an example of a type (a) reaction. 

Sulphur-Nitrogen Compounds.—Linear Compounds. Results from ab initio Hartree-Fock calculations on the ground states of NSF and SSO have been reported.87 The photoelectron spectra of the bent, triatomic molecules NSF, SSO, 03, S02, and NSC1 were compared and experimental details of the photoelectron spectrum of SSO presented. Pyrolysis of the tetrathiatriazyl halide S4N3X at low pressures gives the corresponding thiazyl halide XSN where X = C1 or Br but not where X = I 88... 

A study " " of reactions of cyclo-thiazyl halides with Lewis acids has shown that (SNCO3 and (SNF)j react with SbCls or SbFj, AsFj, and BF3, to give the ionic compounds[S3N,Cl2] [SbCl6] and[S3N3F2] [MF6] (BF4), respectively. On heating, the (NS)3 ring is cleaved, e.g. 

Thiazyl halides, such as thiazyl chloride (XLIV) or thiazyl bromide, the molecular weight of which is unknown, are rapidly solvolyzed by ammonia, in which they dissolve to give a red color. Analysis shows the prod-... 

The hydrohalide elimination route is also widely employed for the synthesis of cyclic sulfur-nitrogen compounds, such as tetrasulfur tetranitride (cyclotetrathiazyl), thiazyl halides, and sulfanuric halides ... 

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. 

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. 

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