Pentafluorosulfanylnitramide Salts

The synthesis and properties of a new class of inorganic salts, named pentafluorosulfanylnitramide salts (or
pentafluorosulfanylnitraminic acid salts) [Z+SF5NNO2-], are described. A number of SF5-nitramide salts
(Z+SF5NNO2-) were successfully prepared via nucleophilic displacements from carbamates and/or ion exchange
techniques, but some salts [M(SF5NNO2)x; M = Li, Mg, Al] decomposed during isolation procedures and appear
to be unstable in the solid state. Single-crystal X-ray diffraction was used to fully characterize the Z+SF5NNO2-,
and their properties/structures are compared with those of the corresponding dinitramide salts (or dinitraminic
acid salts), Z+N(NO2)2-. X-ray crystallography revealed major structural differences between N(NO2)2- and
SF5N(NO2)- salts concerning the N−N distances and the angles subtended at the central nitrogen atom. In the
N(NO2)2- salts, there are two nonequivalent N−N (average lengths 1.372(2) and 1.354(2) Å) distances and an
average N−N−N angle of 115.8(3)° (falls between sp3 and sp2 hybridization). In the SF5NNO2- salts, the average
N−N distance is much shorter, 1.308(9) Å, and the average N−N−S angle is 120.0(5)° (closely fits sp2
hybridization). The SF5NNO2- salts show a remarkable metrical similarity for the SF5 moiety in all structures,
indicating a lack of sensitivity to its steric and electronic environment. This is in marked contrast to N(NO2)2-,
where there is a wide variation in conformations adopted by these anions which can be related to their environment.