Peroxydisulfuryl Difluoride1

[13709-32-5]  · F2O6S2  · Peroxydisulfuryl Difluoride  · (MW 198.14)

(fluorosulfating agent, capable of halogen2-7 and hydrogen abstraction2,8,9 reactions to give esters of fluorosulfuric acid; powerful oxidant10,11)

Physical Data: bp 67.1 °C; mp -55.4 °C.1,11,12

Form Supplied in: colorless liquid with unpleasant odor.

Preparative Methods: can be obtained by the reaction of SO3 with F2 in the presence of AgF211 or by electrolysis of fluorosulfuric acid.12

Handling, Storage, and Precautions: although the reagent appears to be stable and there are no reports of explosive properties, it should be handled with care. It can ignite organic materials upon contact. It is hydrolyzed by water to give oxygen and fluorosulfuric acid.12 Use in a fume hood.

Synthesis of Fluorosulfates.

The chemical behavior of F2S2O6 is determined by two features of its reactivity: (a) the ability to generate the radical species &bdot;OSO2F in the reversible dissociation reaction,2,13 and (b) the high oxidation ability10,11 and, in particular, the generation of high-valent species containing two fluorosulfate groups.1 The reagent (1) smoothly substitutes halogen atoms (Cl, Br, I) for fluorosulfate groups, probably via transient formation of hypervalent species of type (2) (eq 1).3

For example, methyl chloride or bromide reacts with F2S2O6 at -25 °C to give methyl fluorosulfate.2 The reaction is applicable to fluorochlorocarbons (eq 2).4

In the case of perfluoroalkyl iodides the relatively stable hypervalent iodine derivatives of type RfI(OSO2F)2 can be isolated; they are also readily transformed into the corresponding fluorosulfates RfOSO2F.5-7

Perfluoroalkenes react with (1) to give vic-difluorosulfates,14 -17 e.g. eq 3.15

C6F6 also gives a 1,4-addition product and then 1,2,3,4- and 1,2,3,4,5,6-addition products.18

Hydrogen Abstraction.

Reactions of (1) with a variety of organic compounds such as amines, alcohols, thiols, aromatics, and even saturated hydrocarbons, proceed by hydrogen abstraction and addition of an OSO2F moiety (R-H -> ROSO2F).1,2,8,9,19,20 For example, methane gives a mixture of methyl fluorosulfate and methylene difluorosulfate.20 Methyl fluorosulfate also gives methylene difluorosulfate in reaction with (1).2 Hexafluoropropane8 and propionic acid20 react in accordance with eqs 4 and 5.

Hexafluoroacetone imine also reacts with substitution of the imine hydrogen atom (eq 6).19

Benzene gives phenyl fluorosulfate1 and nitrobenzene gives m-nitrophenyl fluorosulfate21, respectively, in reaction with (1).

Oxidation.

Peroxide (1) is a powerful oxidant and can be used for the oxidation of noble metals (Ag, Au, Re, Pt, Os, Rh) to the salts of fluorosulfuric acid.10,22 For example, the oxidation of metallic silver by F2S2O6 in the presence of HOSO2F gives Ag(SO3F)2.22 Oxidation of organic compounds can produce radicals. For example, the trimer (3) of perfluoropropylene reacts with (1) to give stable radical (4), isolated in analytically pure form (eq 7).23

Dimethyl ether reacts with (1) to give dimethoxyethane as the sole product, presumably via selective dimerization of transient methoxymethyl radicals (eq 8).24

Carbon monooxide is oxidized by (1) to CO2.3 Nitroso groups in perfluoronitrosoalkanes are either oxidized to nitro groups or undergo substitution by an OSO2F group.25


1. Fokin, A. V.; Studnev, Yu. N.; Kuznetzova, L. D.; Krotovich, I. N. Usp. Khim. 1982, 51, 1258 (CA 1982, 97, 181 258m).
2. Kirchmeier, R. L.; Shreeve, J. M. IC 1973, 12, 2886.
3. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Kuznetzova, L. D.; Verenikin, O. V.; Krotovich, I. N. IZV 1976, 2422 (CA 1977, 86, 89 108n).
4. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Matveenko, V. I. IZV 1985, 715 (CA 1985, 103, 70 907v).
5. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Tatarinov, A. S.; Pasevina, K. I. IZV 1985, 1669 (CA 1986, 104, 185 943s).
6. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Potarina, T. M.; Kuznetzova, L. D. IZV 1980, 2641 (CA 1981, 94, 191 609d).
7. Schack, C. J.; Christe, K. O. JFC 1980, 16, 63.
8. Fokin, A. V.; Rapkin, A. I.; Matveenko, V. I.; Zakharov, V. Yu.; Studnev, Yu. N. IZV 1986, 252 (CA 1987, 106, 32 320c).
9. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Kuznetzova, L. D.; Komarov, V. A. IZV 1976, 489 (CA 1976, 85, 20 539r).
10. (a) Willner, H.; Aubke, F. IC 1990, 29, 2195. (b) Mallela, P.; Aubke, F. IC 1985, 24, 2969. (c) Lee, K. C.; Aubke, F. IC 1984, 23, 2124. (d) Leung, P. C.; Wong, G. B.; Aubke, F. JFC 1987, 35, 607. (e) Cicha, W. V.; Herring, F. G.; Aubke, F. CJC 1990, 68, 102.
11. (a) Dudley, F. B.; Cady, G. H. JACS 1957, 79, 513. (b) Shreeve, J. M.; Cady, G. H. Inorg. Synth. 1963, 7, 124.
12. Dudley, F. B. JCS 1963, 3407.
13. Zimmerman, E. C.; Ross, J. JCP 1984, 80, 720.
14. Shreeve, J. M.; Cady, G. H. JACS 1961, 83, 4521.
15. Kurykin, M. A.; Krotovich, I. N.; Studnev, Yu. N.; German, L. S.; Fokin, A. V. IZV 1982, 1861 (CA 1982, 97, 215 441h).
16. Kurykin, M. A.; German, L. S.; Studnev, Yu. N.; Fokin, A. V. IZV 1980, 1679 (CA 1980, 93, 238 771x).
17. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Krotovich, I. N.; Verenikin, O. V. IZV 1985, 1094 (CA 1985, 103, 214 819t).
18. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Krotovich, I. N.; Kuznetzova, L. D.; Komarov, V. A. IZV 1976, 946 (CA 1976, 85, 62 723b).
19. Fokin, A. V.; Rapkin, A. I.; Krotovich, I. N. ZOR 1986, 21, 2225 (CA 1986, 105, 171 777z).
20. Coleman, J. P.; Pletcher, D. TL 1974, 147.
21. Fokin, A. V.; Nikolaeva, A. D.; Studnev, Yu. N.; Proshin, N. A.; Leonov, A. G. IZV 1981, 2638 (CA 1982, 96, 85 161h).
22. Leung, P. C.; Aubke, F. IC 1978, 17, 1765.
23. Cherstkov, V. F.; Avetisjan, E. A.; Tumanskyi, B. L.; Sterlin, S. R.; Bubnov, N. N.; German, L. S. IZV 1990, 2450 (CA 1991, 114, 42 026r).
24. Choukroun, H.; Brunel, D.; Germain, A. CC 1986, 6.
25. Fokin, A. V.; Studnev, Yu. N.; Rapkin, A. I.; Krotovich, I. N.; Chilikin, V. G.; Verenikin, O. V. IZV 1984, 832 (CA 1984, 101, 130 177c).

Nikolai S. Zefirov

Moscow State University, Russia



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