NITROGEN NMR OF SOME SULFUR DIIMIDE ANIONS AND CALCULATED (GIAO) NITROGEN SHIELDING CONSTANTS

Sulphur diimide anions of the type [NSN](2-) (1), [RNSN](-) (1), [R = (1)Bu (3), SiMe(3) (4), (1)Bu(2)P (5)] were prepared with the counter ions [(1)Bu(4)N](+) or [(Me(2)N)(3)S](+) (for 1, 3, 4) and K+ (for 5) and studied in solution by N-14 NMR, and for assignment purposes by N- 15 NMR (4). The experimentally determined N-14 chemical shifts (delta N) were compared with nitrogen shielding constants calculated by the g auge included atomic orbitals (GIAO) technique, and a linear relations hip between sigma(N(calc)) and delta N was obtained. This correlation serves to support the Z configuration of the anions [RNSN](-), analogo us to the isoelectronic N-sulphinylamines. On this basis, two N-14 res onance signals reported in the literature with uncertain assignment ca n be attributed to [HNSN](-) (2), and the previously assigned delta N values suggest that the anion [HNSNS](-) (6) adopts the Z/E configurat ion.