Pentafluorosulfanylnitramide salts

The synthesis and properties of a new class of inorganic salts, named pentafluorosulfanylnitramide salts (or pentafluorosulfanylnitraminic acid salts) [Z(+)SF(5)NNO(2)(-)], are described. A number of SF5-nitramide salts (Z(+)SF(5)NNO(2)(-)) 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(+)SF(5)NNO(2)(-), 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) Angstrom) distances and an average N-N-N angle of 115.8(3)degrees (falls between sp(3) and sp(2) hybridization). In the SF5NNO2- salts, the average N-N distance is much shorter, 1.308(9) Angstrom, and the average N-N-S angle is 120.0(5)degrees (closely fits sp(2) 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.