Tetra-cationic imidazoliumyl-substituted phosphorus–sulfur heterocycles from a cationic organophosphorus sulfide

The reaction of imidazoliumyl-substituted P((III)) cations of type [L((R,Me))PCl2](+) (3a,b(+); L(R,Me) = imidazolium-2-yl a: R = Me; b: R = iPr) with (Me3Si)2S leads to the formation of tetra-cationic, eight-membered phosphorus sulfur heterocycles [L((R,Me))PS]4(4+) (9a,b(4+)), which can be explained by the tetramerization of the intermediately formed cationic phosphorus monosulfide [L((R,Me))PS](+) (8a,b(+)). The P4S4 ring adopts a crown conformation as observed for cyclo-S8. The Lewis base DMAP (4-dimethylaminopyridine) initiates a deoligomerization- and dismutation reaction of 9a,b(4+) to give P((I)) centered cation [L((R,Me))2P](+) (12a,b(+)) and phosphorus disulfide [(DMAP)2PS2](+) (14(+)).