The Synthesis and Characterization of Stable Radicals Containing the Thiazyl (SN) Fragment and Their Use as Building Blocks for Advanced Functional Materials - Stable Radicals: Fundamentals and Applied Aspects of Odd-Electron Compounds - page 329

NSAr

Ph

[ox]

NSAr

NH

27

H

NSAr

NSAr

Ar'

Ar' Ar'

NH 2

NSAr NSAr

h n

NSAr

29

Ph

N(SAr) 2

28

NSAr

Ar'

N SAr

ArS N

Ar'

ArSN

30

Scheme 9.9

N

Ph Ph

[ox]

N HN

ArS SAr

32

Ph N Ph Ph N Ph

Ph N Ph

N N NN

ArS SAr ArS SAr

NH NH 2

34

h n

31

Ph N Ph

N N

Ph N Ph

ArS SAr

ArS

33

N N

ArS SAr

Scheme 9.10

9.3.2 1,2,3,5-Dithiadiazolyl radicals
First discovered in the 1970s, the 1,2,3,5-dithiadiazolyl radical 35 is one of the most heavily studied thiazyl
radical systems; Rawson and Banister comprehensively reviewed their chemistry in 1995. 80 Synthetic routes
to 1,2,3,5-dithiadiazolyl radicals nearly always proceed through the corresponding dithiadiazolium cation
36 (Scheme 9.11). The lone alternative route is the rearrangement of isomeric 1,3,2,4-dithiadiazolyl radicals
37 (this reaction is discussed in Section 9.3.5). The cations were first made from the reactions of S 3 N 3 Cl 3
with nitriles 81 or diazenes, 82 or from the reactions of nitriles with a mixture of sulfur dichloride, ammo-
nium chloride, and chlorine. 83 A more recent use of S 3 N 3 Cl 3 in the synthesis of dithiadiazolium chlorides
involves the cycloaddition reaction of the NSCl monomer (obtained by heating S 3 N 3 Cl 3 ) with in situ gen-
erated nitrile sulfides. 84

The reaction of amidines or their hydrochloride salts with sulfur dichloride (SCl 2 )