Cyclic chalcogen-nitrogen oxides

The sulfur-nitrogen oxide S3N20 (thiodithiazyl oxide) is a red liquid, which was first synthesized by the reaction of (Me2SnS2N2)2 with SOF2, but it is more conveniently prepared from [S3N2C1]C1 (Equation l).120 

The 15N NMR spectrum of S3N20 indicates a five-membered ring structure. Lewis acids such as SnCl4 form O-bonded m-adducts with two molecules of S3N20. The neutral, six-membered ring compound S3N205 is obtained when S4N4 or S(NSO)2 is treated with an excess of S02.106 

Cyclotetrathiazene dioxide S4N402 is obtained as orange-yellow needles by the condensation of [S3N2C1]C1 with sulfamide S02(NH2)2.106 Two -N=S=N-units bridge a sulfur atom and an S02 group to form a boat-shaped eight-membered ring. 

The reaction of S02(NH2)2 with sulfuryl chloride followed by the treatment with ammonia produce the ammonium salt of cyclic, chair-shaped [N3S306]3 (47a) anion.121 The selenium analogue [N3Se306]3 (47b) adopts a similar conformation. 

The yellow [S4N50] anion (48) is obtained as the water-soluble ammonium salt from the reaction of SOCl2 with liquid ammonia.69 Its structure is related to that of the binary anion [S4Ns] (24). The [S4N502] ion (49) is prepared 

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The accessibility of the +4 and +6 oxidation states for sulfur and, to a lesser extent, selenium gives rise to both acyclic and cyclic molecules that have no parallels in N-O chemistry. Thus there is an extensive chemistry of chalcogen diimides RN=E=NR (E = S, Se, Te) (Section 10.4). In the case of Te these unsaturated molecules form dimeric structures reflecting the increasing reluctance for the heavier chalcogens to form multiple bonds to nitrogen. The acyclic molecule N=Sp3,... 

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