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Reactions of nitronium sulfates: Hunting for dinitro sulfate
Author(s) -
Zelenov Victor P.,
Khakimov Dmitry V.,
Fedyanin Ivan V.,
Troyan Ivan A.
Publication year - 2019
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.5681
Subject(s) - raman spectroscopy , chemistry , sulfate , decomposition , ion , inorganic chemistry , medicinal chemistry , organic chemistry , optics , physics
Nearly 70 years ago, it was shown that the reaction between equimolar amounts of SO 3 and N 2 O 5 results in dinitronium disulfate (NO 2 ) 2 S 2 O 7 rather than monosulfate (NO 2 ) 2 SO 4 . Because SO 3 can dimerize, it was believed for long that this feature is the main cause of the formation of nitronium disulfate. Then, it was discovered that the reaction of NOSO 3 Cl with N 2 O 5 results in dinitronium disulfate, and (NO 2 ) 2 SO 4 was suggested as an intermediate. The development of Raman spectroscopy made it possible for us to solve the fundamental problem of the existence of an elusive dinitro sulfate. The inevitability of dinitro sulfate formation was demonstrated by the transformations of nitronium sulfates (NO 2 ) 2 S 2 O 7 , NO 2 HSO 4 , and (NO 2 )[CF 3 C(O)OSO 3 ], and the Raman spectroscopy technique has shown the presence of the compound in the solid reaction products. In order to establish the structure of solid dinitro sulfate, quantum chemical calculations of the nitro ester form (O 2 NOSO 3 NO 2 ) and of the [OSO 3 NO 2 ] − anion were performed, but the conclusions about the diionic structure [NO 2 ] + 2 [SO 4 ] 2− were made only due to the synthesis of the related nitronium sulfates K (NO 2 )SO 4 and K (NO 2 )S 2 O 7 whose Raman spectra were compared with that of dinitro sulfate. The decomposition pathways of all these unstable molecules were established. Reactions of nitronium disulfates, (NO 2 ) 2 S 2 O 7 or (NO 2 )[CF 3 C(O)OS 2 O 6 ], with CF 3 COOH showed that, unlike HNO 3 , the organic acid does not destroy the sulfate chains but can substitute terminal groups including nitronium ion. So the chemistry of nitronium monosulfates was studied for the first time, and the existence of an unstable dinitronium sulfate was proved using Raman spectroscopy.