Sulfur diimide anions, RNSN

Salts of mono-alkylated or arylated sulfur diimide anion [RNSN] (R = aryl, Bu, SiMcs) are prepared by Si-N cleavage of RNSNSiMcs with [(Me2N)3S][Mc3SiF2]. ° ° These anions adopt cis configurations with very short terminal S-N bond lengths (1.44 - 1.49 A) indicative of a thiazylamide anion, [RNS N] (5.21). ... 

Several methods for the preparation of unsymmetrical sulfur diimides RN=S=NR have been developed. One approach involves the addition of a catalytic amount of an alkali metal to a mixture of two symmetrical sulfur diimides, RN=S=NR and RT8i=S=NR. A second method makes use of alkali-metal derivatives of [RNSN] anions.Eor example, derivatives in which one of the substituents is a fluoroheteroaryl group can be prepared by the reaction of the anionic nucleophile [RN=S=N] with pentafluoropyridine. Sulfur diimides of the type RN=S=NH (R = 2,4,6- Bu3C6H2S) have also been prepared. "... 

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