Sulfur diimide
Sulfur diimides are chemical compounds of the formula S(NR)2. The parent member, S(NH)2, is of only theoretical interest. Other derivatives where R is an organic group are stable and useful reagents.
Organic derivatives
A particularly stable derivative is di-t-butylsulfurdiimide.[1] A yellow oil, it is prepared by reaction of tert-butylamine with sulfur dichloride to give the intermediate "S(N-t-Bu)", which decomposes at 60 °C to give the diimide. Other routes to sulfur diimides involve treatment of sulfur tetrafluoride with amines. A third route involves transimidation of disulfonylsulfodiimide:
- S(NSO2Ph)2 + 2 RNH2 → S(NR)2 + 2 PhSO2NH2
Structure, bonding, reactions
These compounds are related to SO2. They have planar SN2C2 cores, although both syn and anti isomers are observed.
Sulfur diimides are electrophilic. They undergo Diels-Alder reaction with dienes.[1] Organolithium compounds add to give the corresponding anions:
- R'Li + S(NR)2 → R'S(NR)(NRLi)
The triimido analogues of sulfite can be generated by treating the sulfur diimides with amide:[2]
- 4 LiNHBu-t + 2 S(NBu-t)2 → 2 Li2S(NBu-t)3 + 2 t-BuNH2
References
- ^ a b Kresze, G.; Wucherpfennig, W., "Organic synthesis with imides of sulfur dioxide", Angew. Chem. Int. Ed. Engl. 1967, volume 6, 149-167. doi:10.1002/anie.196701491
- ^ Fleischer, R.; Stalke, D., "A new route to sulfur polyimido anions S(NR)nm-: reactivity and coordination behavior", Coord. Chem. Rev. 1998, 176, 431-450. doi:10.1016/S0010-8545(98)00130-1