Cyclic S-N compounds and phosphorus reagents--Part XVIll¹: Synthesis and X-ray structural characterization of phosphiniminocyclotrithiazenes with a primary amino substituent

1052-1056First examples of phosphiniminocyclotrithiazenes containing a primary amino group, (Ph)(R)(iPrNH)PN-S3N3 [R=(i) Ph. I and (ii) DCA (dicyclohexylamino), II] have been isolated from room temperature reactions of S4N4. with the corresponding phosphine in acetonitrile. Single crystal X-ray structure of compounds I and II reveal very similar endocyclic structural features, but for the deviation of tricoordinate sulphur [S(l)] from the mean plane of the ring. The primary amino group [(CH3)2CHNH]binds equally strongly in I and II, but the N-H bonds show differences in both bond length and orientation with respect to the adjacent P-N bond. Heterocycles I and II show different sensitivities for ring conversion to cyclophosphathiazene