The protonation of dithiocarbamic acid in superacids HF/MF5: Synthesis and characterization of H_2NC(SH)_2 ~+ MF_6 ~- (M = As, Sb)

摘要

Dithiocarbamic acid reacts in the superacidic media HF/MF_5 (M = As, Sb) under formation of the corresponding salts H_2NC(SH) _2 ~+ MF_6 ~-. The colorless compounds are stable in an inert gas atmosphere up to -20°C. The salts have been characterized by NMR, IR and Raman spectroscopy. Reactions in DF/AsF5 were carried out to obtain D_2NC(SD) _2 ~+ AsF _6 ~- in order to confirm the assignments of the observed vibrational modes. Additionally, quantum-chemical calculations of the free cation, [A_2NC(SA) _2]~+ (A=H, D), and of the [A_2NC(SA) _2(3HF)]~+ unit on the PBE1BPE/6-311G(3df,3pd) level of theory are discussed.