Sulfanuric fluoride

The fluoride [NS(0)F]3 is more stable thermally and towards nucleophilic reagents than the corresponding chloride. For example, 8.15a is hydrolyzed by water to NH(S02NH2)2, whereas sulfanuric fluoride is unaffected by cold water. In warm water, however, hydrolysis occurs to give the [N3S304F2] anion. All three fluorine atoms in [NS(0)F]3 can be replaced by primary or secondary amines at 80-90°C in the absence of a solvent. Mono- or diphenyl derivatives can be prepared by treatment of [NS(0)F]3 with PhLi in diethyl ether at -70°C, while the Friedel-Crafts reaction with benzene at reflux in the presence of AICI3 gives two isomers of [NS(0)Ph]3. ... 

The fluoride [NS(0)F]3 is obtained as a mixture of so-called cis and trans isomers by the fluorination of [NS(0)C1]3, preferably with SbF3 This cis isomer shows a singlet in the F NMR spectrum consistent with a structure in which all three fluorine atoms are on the same side of the S3N3 ring cf. [NS(0)C1] 3, while the trans isomer exhibits an ABj pattern, indicating that one fluorine is on the side of the ring opposite to the other two . Trimeric sulfanuric fluoride has also been obtained by the thermal decomposition of Cs[NS(0)F2], Hg[NS(0)F2]2 B[NS(0)F2]3 or Me3Sn[NS(0)F2] which occurs at RT for the Sn compound. 

Sulfanuric halides contain the characteristic group -N=S(0)X- (X = Cl, F). Unlike the isoelectronic cyclophosphazenes (NPClajx (x = 3-17), " only six-membered rings have been well characterized. The sulfanuric halides are colourless solids (X = Cl) or liquids (X = F), which are stable in dry air. Sulfanuric chloride [NS(0)C1]3 is best prepared by treatment of SOCI2 with sodium azide in acetonitrile at -35°C (Eq. 8.16). It may also be obtained as a mixture of a- and yS-isomers in a two-stage reaction from H2NSO3H and PCls. The fluoride [NS(0)F]3 is formed as a mixture of isomers by the fluorination of [NS(0)C1]3 with Sbp3. ... 

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