REACTIVITY OF NITROGEN BASES NH3, NC-NH2 AND NC-CN WITH EF(5) AND EF(5) HF (E=AS, SB)/

The reaction of ammonia, cyanamide and cyanogen with arsenic pentafluo ride in liquid SO2 led to the formation of the adducts NH3.AsF5 (1), H 2N-CN.AsF5 (2) and NC-CN.AsF5 (3). Similarly, the compound NC-CN.SbF5 (4) was obtained from (CN)(2) and SbF5 in sulfur dioxide solution. The adduct 1 was treated wit HF (excess) to give NH4+ AsF6- in quantitati ve yield. Protonation of H2N-CN and (CN)(2) with anhydrous HF in the p resence of EF(5) (E=As, Sb) afforded the salts H2N-CNH+ AsF6- (5) and NC-CNH+ SbF6- (6), the latter being only stable in solution and existi ng in equilibrium with 4 (4/6=4:1). Fluorination of 2 with elemental f luorine in C2F4Cl2, solution (R-114) led to the formation of 3, NH4+As F6- and (presumably) NF3. In order to assign the vibrational spectra ( Raman) of 3 and 4, ab initio calculations were carried out on the HF/6 -31G theory level using NC-CNH+ as a model for 3 and 4 (H+ as a Lewis acid instead of AsF5 or SbF5, respectively).