A new route to the syntheses of N-(fluorosulfuryl)sulfonamide salts: Crystal structure of Ph4P+ [CF3SO2NSO2F]-

Article abstract of DOI:10.1016/j.poly.2009.11.024

A new route for the preparation of potassium and tetraphenylphosphonium salts of N-(fluorosulfuryl)trifluoromethane sulfonamide is described. N-(chlorosulfuryl)-trifluoromethane sulfonamide CF₃SO₂-NH-SO₂Cl, that was used for preparations of both salts, was prepared by the reaction of trifluoromethane sulfonamide CF₃SO₂NH₂ and chlorosulfonic acid in the presence of SOCl₂. The obtained N-(chlorosulfuryl)trifluoromethane sulfonamide was converted to potassium N-(fluorosulfuryl)trifluoromethane sulfonamide by using anhydrous KF. Potassium N-(fluorosulfuryl)trifluoromethane sulfonamide served as a starting material for the preparation of the corresponding tetraphenylphosphonium N-(fluorosulfuryl)trifluoromethane sulfonamide that crystallizes from the aqueous solution of potassium N-(fluorosulfuryl)trifluoromethane sulfonamide and tetraphenylphosphonium chloride. N-(fluorosulfuryl)trifluoromethane sulfonamide tetraphenylphosphonium salt is tetragonal, space group P over(4, ?).

Full text of DOI:10.1016/j.poly.2009.11.024

Polyhedron 29 (2010) 991–994
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Polyhedron
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A new route to the syntheses of N-(fluorosulfuryl)sulfonamide salts:
Crystal structure of Ph4P+ [CF3SO2NSO2F]À
a
b,
c
*
ˇ
ˇ
Martin Beran , Jirí Príhoda , Jan Taraba
a
ˇ
Institute of Analytical Chemistry of ASCR, v.v.i., Veverí 97, 602 00 Brno, Czech Republic
Department of Chemistry, Faculty of Science, Masaryk University, Kotlárská 2, 611 37 Brno, Czech Republic
Episcopical High School, Barvicova 85, 602 00 Brno, Czech Republic
b
c
ˇ
ˇ
a r t i c l e i n f o
a b s t r a c t
Article history:
A new route for the preparation of potassium and tetraphenylphosphonium salts of N-(fluorosulfuryl)tri-
fluoromethane sulfonamide is described. N-(chlorosulfuryl)-trifluoromethane sulfonamide CF3SO2–NH–
SO2Cl, that was used for preparations of both salts, was prepared by the reaction of trifluoromethane sul-
fonamide CF3SO2NH2 and chlorosulfonic acid in the presence of SOCl2. The obtained N-(chlorosulfuryl)tri-
fluoromethane sulfonamide was converted to potassium N-(fluorosulfuryl)trifluoromethane sulfonamide
by using anhydrous KF. Potassium N-(fluorosulfuryl)trifluoromethane sulfonamide served as a starting
material for the preparation of the corresponding tetraphenylphosphonium N-(fluorosulfuryl)trifluorom-
ethane sulfonamide that crystallizes from the aqueous solution of potassium N-(fluorosulfuryl)trifluo-
romethane sulfonamide and tetraphenylphosphonium chloride. N-(fluorosulfuryl)trifluoromethane
Received 4 August 2009
Accepted 30 November 2009
Available online 21 December 2009
Keywords:
N-(fluorosulfuryl) sulfonamides
N-(fluorosulfuryl)trifluoromethane
sulfonamide
N-(chlorosulfuryl)trifluoromethane
sulfonamide
ꢀ
sulfonamide tetraphenylphosphonium salt is tetragonal, space group P4.
Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction
formation of CF3SO2–NH–SO2–NH–SO2CF3 whereas the expected
CF3SO2–NH–SO2F was present only in negligible amounts in the
Salts of N-(fluorosulfuryl) sulfonamide of the general formula
RSO2N(À)SO2F are structurally similar to the salts of imido-bis(sul-
furic) acid difluoride, (FSO2)2NÀ. Therefore similar physico-chemi-
cal properties of both classes of these compounds can be expected.
Simple synthesis of potassium and lithium bis(fluorosulfuryl)
imides was published earlier [1,2] and both compounds belong
to industrially very interesting and perspective materials. These
salts have found their utilization as constituents of electrolytes in
lithium batteries and therefore similar exploitation in the case of
N-(fluorosulfuryl) sulfonamide salts can be expected. Other
N-(fluorosulfuryl) sulfonamide salts were only rarely studied and
the only suitable synthesis of CF3SO2–NH–SO2F and its silver salt
was published in [3].
The preparation of CF3SO2–NH–SO2F consisted of the reaction of
CF3SO2N@PCl3 with HSO3F with a yield of approx. 90%. CF3SO2–
NH–SO2F was isolated by fraction distillation from the reaction
mixture and was converted into Ag-salt by the reaction with silver
oxide in benzene. However, this synthetic route is, in fact, appar-
ently more complex as shown by Taraba et al. [4]. In their attempts
to prepare CF3SO2–NH–SO2F they proved that the reaction
between CF3SO2N@PCl3 with HSO3F leads predominantly to the
reaction mixture. We also tried to prepare CF3SO2–NH–SO2F in a
similar way but the product CF3SO2–NH–SO2F contained residual
POCl3 that could not be removed by fraction distillation (proved
by 31P NMR spectroscopy). Therefore this product cannot be used
for the preparation of the salts, and another route had to be found
out.
Recently, we studied the reaction between amidosulfuric,
HSO3NH2, and chlorosulfuric, HSO3Cl, acids in thionyl chloride
[1]. The main product of this reaction was imido-bis(sulfuric)acid
dichloride, (ClSO2)2NH, that was formed easily and almost in quan-
titative yield. This led us to the idea that the reaction of similar
compounds, e.g. alkyl sulfonamide with chlorosulfuric acid, could
lead to the formation of the corresponding N-(chlorosulfuryl)alkyl
sulfonamides. Suggested course of the reaction between trifluo-
romethane sulfonamide (1) with chlorosulfuric acid, HSO3Cl, in
thionyl chloride is shown in Scheme 1.
The compound (2) is intended to be used for preparations of N-
(fluorosulfuryl)trifluoromethane sulfonamides by simple conver-
sion with the corresponding fluorides.
This article deals with a new route to the synthesis of N-(chlo-
rosulfuryl)trifluoromethane sulfonamide (2) and potassium (3)
and tetraphenylphosphonium (4) salts of N-(fluorosulfuryl)trifluo-
romethane sulfonamide. The compound (4) is the first substance in
which the structure of N-(fluorosulfuryl)trifluoromethane sulfon-
amide anion was determined by X-ray diffraction.
* Corresponding author. Tel.: +420 549496690; fax: +420 549492443.
ˇ
E-mail address: prihoda@chemi.muni.cz (J. Príhoda).
0277-5387/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2009.11.024

992
M. Beran et al. / Polyhedron 29 (2010) 991–994
and 1325–1362 cmÀ1, respectively. The band belonging
msCF3
can be expected in the region around 1100 cmÀ1 but was not
observed.
2.3. Tetraphenylphosphonium N-(fluorosulfuryl)trifluoromethane
sulfonamide (4)
Scheme 1. Suggested course of N-(chlorosulfuryl)trifluoromethane sulfonamide (2)
synthesis.
Since attempts at crystal growth of (3) were not successful
X-ray structure determinations could not be carried out. However,
another salt containing the same anion could be prepared. Well
crystallizing tetraphenylphosphonium salt (4) was prepared by
precipitating of (3) with tetraphenylphosphonium chloride in
aqueous solution (Scheme 3). The pure product was isolated by
extraction into CH2Cl2.
The compound (4) was fully characterized by X-ray structural
analysis and it can be assumed that the structure of the anion in
potassium salt (3) is expected to achieve very similar geometry.
The structure of N-(fluorosulfuryl)trifluoromethane sulfonamide
anion in (4) is the first known structure of this compound type.
2. Results and discussion
2.1. N-(chlorosulfuryl)trifluoromethane sulfonamide (2)
The reaction between trifluoromethane sulfonamide (1) and
HSO3Cl in SOCl2 led to the formation of a hygroscopic compound
which yielded a white solid (69%) after recrystallization from
CCl4. When exposed to air fumes are evolved due to the hydrolysis
and formation of gaseous HCl. Only one dominant resonance signal
at À75.49 ppm can be found in 19F NMR spectrum. Other resonance
signals are negligible which indicates high fluorine purity of the
compound (2).
2.4. Crystal structure of tetraphenylphosphonium
N-(fluorosulfuryl)trifluoromethane sulfonamide (4)
2.2. Potassium N-(fluorosulfuryl)trifluoromethane sulfonamide (3)
ꢀ
The substance (4) crystallizes in tetragonal space group P4. All
details describing its structure follow from Table 1 and Fig. 1.
Comparison of basic bond lengths and angles to the equivalent
data of similar salts of imido-bis(sulfuric acid) difluoride is shown
in Table 2.
The conversion of (2) to (3) by using potassium fluoride can be
carried out with the crude product, i.e. without preliminary recrys-
tallization described above. The conversion process leading to
potassium N-(fluorosulfuryl)trifluoromethane sulfonamide (3)
was carried out by heating the mixture of the crude (2) with anhy-
drous KF in absence of a solvent at 170 °C (similar approach was
used for converting of imido-bis(sulfuric)acid dichloride into
potassium bis(fluorosulfuryl) imide [1]) – Scheme 2.
The yield of potassium N-(fluorosulfuryl)trifluoromethane sul-
fonamide (3) was 84% (related to trifluoromethane sulfonamide).
This substance was characterized by 19F NMR spectroscopy. There
are two main resonance signals in 19F NMR spectrum (in THF) – a
quartet (d = 55.6 ppm, JFF = 5 Hz, relative intensity 33.6, –SO2F) and
a doublet (d = À79.6 ppm, JFF = 5 Hz, relative intensity 97.2, –
SO2CF3). A negligible signal belongs apparently to fluorine atoms
of bis(fluorosulfuryl) imide anion (d = 51.3 ppm, relative intensity
1). The fluorine spectrum of potassium N-(fluorosulfuryl)trifluo-
romethane sulfonamide (3) is in agreement with the suggested
structure and is very well comparable to the published 19F NMR
spectra of free N-(fluorosulfuryl)trifluoromethane sulfonamide
(doublet À77.7 ppm, quartet 58.5 ppm, JFF = 2.9 Hz) and its silver
salt (doublet À79.3 ppm, quartet 56.2 ppm, JFF = 3.4 Hz) [3].
The compound (3) was characterized by Raman spectroscopy.
An attempt to assign some basic vibrations was done on the basis
of analogy with spectra of alkali metal bis(fluorosulfuryl) imides
[2], ammonium bis(fluorosulfuryl) imide [5], and FXeN(SO2F)2 [6].
The dominating band at 743 cmÀ1 was assigned to the valence
It follows from Table 2 that the corresponding bond lengths
both in (4) and other bis(fluorosulfuryl) imides are comparable
in most cases. Rather longer is the S1–O1 bond; the bond
length is 1.484 Å in (4) while lengths of the same bond in bis(flu-
orosulfuryl) imides are in the interval 1.378–1.423 Å. On the
other hand, the bond S1–N1 (in (4) is 1.529 Å) is shorter as
compared to other S–N bonds in bis(fluorosulfuryl) imides
(1.556–1.642 Å). This means that the S1–N1 bond in (4) has
higher bond order. The SNS angle in all compared substances is
practically identical (123–124°) with the only exception of
CsN(SO2F)2 (120.8°).
3. Experimental
All reactions except preparation of the Ph4P salt were
performed under nitrogen and anhydrous conditions using con-
ventional Schlenk techniques.
Solvents were supplied by Lachema and dried by conventional
methods prior to use. Thionyl dichloride was supplied by Web
Laborchemie Apolda and distilled with quinoline and linen oil be-
fore use. Potassium fluoride dihydrate was supplied by Lachema
and converted to anhydrous salt by heating under vacuum. Chloro-
sulfuric acid 98% was supplied by Fluka. Trifluoromethane sulfon-
amide was supplied by Rhodia and tetraphenylphosphonium
chloride by Lachema.
vibration
position of the corresponding band of potassium bis(fluorosulfuryl)
imide (749 cmÀ1). Valence vibration
SF corresponds to the band at
858 cmÀ1, vibrations asSO2 to the bands at 1237 cmÀ1
sSO2 and
msSNS. This wavelength is almost consistent with the
19F NMR spectra were recorded in THF using a Bruker AVANCE
DRX 300 instrument.
m
m
m
Scheme 2. Synthesis of potassium N-(fluorosulfuryl)trifluoromethane sulfonamide
(3).
Scheme 3. The synthesis of tetraphenylphosphonium N-(fluorosulfuryl)trifluorom-
ethane sulfonamide (4) from (3).

M. Beran et al. / Polyhedron 29 (2010) 991–994
993
Table 1
Crystal data and structure refinement for Ph4P+ CF3SO2NÀSO2F (4).
3.1. N-(chlorosulfuryl)trifluoromethane sulfonamide CF3SO2NHSO2Cl
(2)
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
Unit cell dimensions
a (Å)
C25H20F4NO4PS2
569.51
120(2)
About 7.5 g (0.05 mol) trifluoromethane sulfonamide (1) was
suspended in 6 ml (0.08 mol) thionyl dichloride and 3.3 ml
(0.05 mol) chlorosulfuric acid was added. The mixture was heated
in oil bath (140 °C) for 22 h under reflux condenser closed with
CaCl2 drying tube. Light brown reaction mixture was formed and
SOCl2 was removed by vacuum distillation (650 Pa, 70 °C). After
cooling, the compound (2) crystallized from a viscous residue.
Then, (2) was recrystallized from 15 ml of hot tetrachloromethane.
White, crystalline product was washed with 5 ml CCl4 and dried by
650 Pa. Yield 8.6 g (69%).
0.71073
tetragonal
ꢀ
P4
18.600(3)
18.600(3)
7.0782(14)
90°
90°
90°
2448.7(7)
4
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
Volume (Å3)
19F NMR (CH2Cl2): À75.49 ppm (singlet); Raman: 135 (s),
261 (w), 268 (m), 297 (m), 323 (m), 358 (w), 381 (w), 420 (vs),
546 (vw), 558 (vw), 576 (w), 602 (vw), 629 (vw), 772 (vs), 819
(vw, br), 1116 (vw), 1180 (w), 1236 (s), 1314 (vw), 1422 (vw),
1441 (w).
Z
Calculated density (mg/m3)
Absorption coefficient (mmÀ1
F(0 0 0)
1.545
0.348
1168
)
Crystal size (mm)
h Range for data collection
Limiting indices
0.1 Â 0.07 Â 0.05
3.46–24.99°
À22 6 h 6 16
À22 6 k 6 22
À8 6 l 6 8
3.2. Potassium N-(fluorosulfuryl)trifluoromethane sulfonamide
K[CF3SO2NSO2F] (3)
Reflections collected/unique
13952/4316 [Rint = 0.1054]
99.4%
Completeness to
H = 25.00
About 15 g (0.26 mol) of finely powdered anhydrous potassium
fluoride was suspended in 20 ml dichloromethane and crude (non-
recrystallized) CF3SO2NHSO2Cl (2), prepared from 7.5 g (0.05 mol)
trifluoromethane sulfonamide (1), and 20 ml dichloromethane,
were added under vigorous stirring. Dichloromethane was subse-
quently distilled off at 650 Pa. Then, the solid residue was heated
on oil bath (170 °C, 650 Pa) for 2 h. A 15 ml of dry n-butylacetate
was added to the hot pasty grey mixture and the mixture was
homogenized with a glass stick. After cooling, the mixture was
three times extracted with 15 ml tetrahydrofurane portions. Com-
bined extracts were evaporated in vacuum (2 kPa, 60 °C) until crys-
tallization began. About 50 ml dichloromethane was added under
constant stirring, the white solid was filtered off, washed with
dichloromethane and dried in vacuum at 650 Pa. Yield 11.3 g
(83.5%).
Refinement method
Full-matrix least-squares on F2
4316/0/334
Data/restraints/parameters
Goodness-of-fit on F2
0.752
Final R indices [I > 2
R indices (all data)
r
(I)]
R1 = 0.0548, wR2 = 0.0604
R1 = 0.1286, wR2 = 0.0791
0.11(11)
0.378 and À0.284
Absolute structure parameter
Largest difference in peak and hole (e ÅÀ3
)
Raman spectra were recorded on a FT-IR Bruker EQUINOX IFS
55/S spectrometer with FRA 106/S equipment using Nd:YAG laser
(k = 1064 nm), maximal output 500 mW. Samples were measured
in glass ampoules. Intensity data were collected on a KUMA KM-
4 j-axis diffractometer equipped with CCD detector with graphite
monochromated Mo K
a radiation (k = 0.71073 Å) at 120 K. The
structure was solved by direct methods and refined anisotropically
by full-matrix least-squares method. The software packages used
were: XCALIBUR CCD system for the data collection/reduction [7],
and SHELXTL V5.1 system for the structure solution, refinement,
and drawings (thermal ellipsoids are drawn at the 50% probability
level) [8].
19F NMR (THF): 55.6 ppm (quartet, JFF = 5 Hz, Int. = 33.6),
À79.6 ppm (doublet, JFF = 5 Hz, Int. = 97.2); Raman: 178 (vw, br),
286 (m), 314 (w), 329 (m), 342 (m), 402 (w, br), 420 (vw), 478
(vw), 541 (vw), 556 (vw), 573 (vw), 616 (vw), 636 (vw), 743 (vs),
858 (vw), 1144 (vw), 1191 (w), 1237 (s), 1325 (vw), 1362 (vw).
Fig. 1. The molecular structure of Ph4P+ CF3SO2NÀSO2F (4). Thermal ellipsoids are drawn on the 50% probability level.

994
M. Beran et al. / Polyhedron 29 (2010) 991–994
Table 2
Bond lengths [Å] and angles [°] for (4) and bis(fluorosulfuryl) imides.
Ph4P+CF3SO2NÀSO2F (4)
HN(SO2F)2 [9]
LiN(SO2F)2 [2]
KN(SO2F)2 [9]
CsN(SO2F)2 [10]
S1–O1
S1–O2
1.471(4)
1.394(5)
1.404(3)
1.403(8)
1.409(1)
1.423(1)
1.413(7)
1.378(5)
1.406(2)
1.419(2)
S–O bond length (second SO2F group)
1.392(2)
1.410(1)
1.395(2)
1.416(2)
1.413(2)
1.422(1)
1.413(8)
1.388(2)
S1–N1
S–N bond length (second SO2F group)
S1–F1 1.510(4)
S–F bond length (second SO2F group)
1.540(5)
1.612(3)
1.642(1)
1.511(1)
1.516(4)
1.556(2)
1.556(2)
1.541(1)
1.541(1)
1.558(3)
1.577(2)
1.557(3)
1.569(3)
1.558(2)
1.576(2)
1.518(8)
1.560(2)
S2–O3
S2–O4
S2–N1
S2–C25
C25–F2
C25–F3
C25–F4
1.416(4)
1.446(4)
1.572(6)
1.758(7)
1.361(7)
1.348(7)
1.337(7)
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
O1–S1–O2
O–S–O angle (second SO2F group)
O3–S2–O4
S1–N1–S2
112.1(3)
123.2(2)
123.9(2)
–
118.1(1)
118.1(1)
–
118.3(2)
120.1(2)
–
119.7(2)
119.3(1)
–
117.8(3)
123.5(4)
123.4(2)
123.0(1)
124.2(2)
120.8(2)
3.3. Tetraphenylphosphonium N-(fluorosulfuryl)trifluoromethane
and R values (Table 1). Thus, some structural parameters are
r
sulfonamide Ph4P[CF3SO2NSO2F] (4)
not of a commonly accepted precision.
Solution of 2.4 g (6.4 mmol) of tetraphenylphosphonium chlo-
ride in 20 ml water was mixed with 10 ml dichloromethane and
the solution of 1.7 g (6.3 mmol) of potassium N-(fluorosulfuryl)tri-
fluoromethane sulfonamide (3) in 10 ml water was added under
constant stirring. White precipitate was formed in the course of
reaction and was quickly dissolved in dichloromethane that was
present in the reaction mixture. The organic phase was subse-
quently separated and the aqueous phase was three times ex-
tracted with 10 ml dichloromethane portions. Combined organic
extracts were dried by anhydrous MgSO4 and the solvent was par-
tially removed in vacuum (2 kPa, 40 °C) to obtain final volume of ca
5 ml. Then, 25 ml diethylether was slowly added under constant
stirring. White, crystalline product was precipitated. It was filtered
off, washed with ether (3 Â 10 ml) and dried at 650 Pa. Yield 2.7 g
(74%) of white needle-like crystals.
Supplementary material
CCDC 710001 contains the supplementary crystallographic
data for tetraphenylphosphonium N-(fluorosulfuryl)trifluorome-
thane sulfonamide, Ph4P[CF3SO2NSO2F]. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html, or from the Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-
336-033; or e-mail: deposit@ccdc.cam.ac.uk.
Acknowledgement
This work was supported by the Institutional Research Plan
AV0Z40310501.
19F NMR (THF): 55.97 ppm (singlet), À79.07 ppm (singlet); Ra-
man: 111 (s, br), 199 (w, br), 249 (w), 260 (vw), 293 (vw), 324
(vw), 347 (vw), 615 (w), 679 (w), 711 (vw), 724 (vw), 757 (vw),
999 (vs), 1027 (m), 1097 (w), 1108 (vw), 1163 (vw), 1187 (vw,
br), 1238 (vw, br), 1317 (vw), 1343 (vw), 1437 (vw), 1577 (w),
1586 (m).
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