Synthesis and structural characterization of highly fluorinated sulfimides and sulfoximides as functional building blocks for materials science

Article abstract of DOI:10.1002/ejoc.200400702

Several examples of highly fluorinated sulfimides and sulfoximides have been synthesized in order to assess their potential usefulness as functional materials, such as liquid crystals or as active components in molecular electronics. The polarity of liquid crystals with these types of functional groups was lower than expected, due to conformational effects. A new synthetic method provides a convenient access to N,S,S-triaryl sulfimides and sulfoximides, which were characterized by X-ray crystallography. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.

Full text of DOI:10.1002/ejoc.200400702

FULL PAPER
Synthesis and Structural Characterization of Highly Fluorinated Sulfimides
and Sulfoximides as Functional Building Blocks for Materials Science
Peer Kirsch,*[a] Marc Lenges,[a] Daniel Kühne,[b] and Karl-Peter Wanczek[b]
Dedicated to Professor Gerd-Volker Röschenthaler on the occasion of his 60th birthday
Keywords: Conformation analysis / Liquid crystals / Materials science / Organofluorine chemistry / Organosulfur chemistry
Several examples of highly fluorinated sulfimides and sulfox-
imides have been synthesized in order to assess their poten-
tial usefulness as functional materials, such as liquid crystals
or as active components in molecular electronics. The po-
larity of liquid crystals with these types of functional groups
was lower than expected, due to conformational effects. A
new synthetic method provides a convenient access to N,S,S-
triaryl sulfimides and sulfoximides, which were charac-
terized by X-ray crystallography.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
ripheral display components, such as UV-curable sealants
or the polyimide orientation layer. Using suitable model
systems, the propensity of new types of functional materials
to generate ions or to mobilize them by coordinative solv-
ation can be conveniently studied in detail in the gas phase
by ion cyclotron resonance (ICR) mass spectrometry.
Introduction
N-(Trifluoromethylsulfonyl)sulfimides and -sulfoximides
are among the strongest electron-withdrawing functional
groups known.[1] For example, the -SCF3(=NSO2CF3) and
the -SCF3(=O)(=NSO2CF3) groups have σ constants of
p
+1.39 and +1.55, respectively, far exceeding the values for
more common, highly polar groups, such as nitro (+0.78),
cyano (+0.66) or trifluoromethylsulfonyl (+1.17).[2] Never-
theless, these remarkable electronic properties have never
been put to practical use for materials science. Mostly due
to preparative difficulties and potentially hazardous syn-
thetic procedures,[3] only a limited number of organic com-
pounds carrying these functionalities has been synthe-
sized.[1,3,4]
Synthesis and Characterization of the Liquid Crystals
For the design of suitable, highly polar liquid crystals
we chose the 4-propyl-4Ј-phenylbicyclohexyl unit as the me-
sogenic core structure. The phenyl moiety should be substi-
tuted in the terminal position by the sulfimide or sulfoxim-
ide groups and flanked by two lateral fluorine atoms for an
additional increase of the dielectric anisotropy. The synthe-
sis started from the trifluoromethylthio derivative 3,[6]
which was oxidized to the sulfoxide 4 with 3-chloroperben-
zoic acid (MCPBA). A by-product of the oxidation was the
trifluoromethylsulfonyl-substituted compound 5. The trifli-
mide residue was introduced in analogy to the general pro-
cedure introduced by Yagupolskii and coworkers[1] by acti-
vation of the sulfoxide 4 with triflic anhydride, followed by
reaction with triflic amide (see Scheme 1, box), to give the
sulfimide 6 in 16% yield. Several failed attempts to oxidize
S-aryl-S-trifluoromethyl-N-(trifluoromethylsulfonyl)sulfim-
ides to the corresponding sulfoximides led Yagupolskii to
the conclusion that the oxidation is not possible due to the
extremely electron-deficient character of the sulfur atom.[1]
In contrast to this result, we were able to achieve the oxi-
dation of 6 to 7 with the RuCl3/NaIO4 system[7] in reason-
able yield (41%), even in the presence of the two additional
electron-withdrawing ortho-fluorine substituents.
For the design of liquid crystalline materials for liquid
crystal display (LCD) applications, there is often a need for
highly polar, so-called “super fluorinated materials” (SFM)
[5]
that can be used as additives for increasing the dielectric
anisotropy (∆ε) of liquid crystal mixtures. In this context,
the superpolar sulfimide and sulfoximide groups became
the focus of our attention.
The performance of liquid crystalline materials for dis-
play applications relies critically on the absence of ionic im-
purities in the medium.[5] Ions can either be introduced by
charge injection, i.e. by electrochemical oxidation or re-
duction, or by the extraction of ionic impurities from pe-
[a]
Merck KGaA, Liquid Crystals Division
64271 Darmstadt, Germany
Fax: +49-6151-722593
E-Mail: peer.kirsch@merck.de
[b]
Institute of Inorganic and Physical Chemistry, University of
Bremen,
Haferwende 12, 28357 Bremen, Germany
Eur. J. Org. Chem. 2005, 797–802
DOI: 10.1002/ejoc.200400702
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
797

P. Kirsch, M. Lenges, D. Kühne, K.-P. Wanczek
FULL PAPER
Scheme 1. Synthesis of the liquid crystals 3–7: a) 1. BuLi, THF, –70 °C. 2. I2, THF, –40 °C (78%); b) CuSCF3, NMP, 120–150 °C, 18 h
(56%); c) MCPBA, CH2Cl2, room temp., 3 d (4: 28%; 5: 7%); d) Tf2O, TfNH2, CH2Cl2, room temp., 18 h (16%); e) NaIO4, RuCl3
(0.1 mol%), CH3CN, H2O, CCl4, room temp., 18 h (41%). The inset illustrates the reaction of the nucleophile (H2N-RF, in this case triflic
amide) with the sulfoxide activated by triflic anhydride.
None of the newly synthesized materials exhibits a meso- of the sulfoximide terminal group. This counterintuitive
phase. Nevertheless, as a component of a nematic host mix- finding illustrates that the dielectric anisotropy (∆ε), as a
ture, they behave like typical liquid crystalline additives and characteristic of the supramolecular arrangement in the ne-
contribute to the anisotropic properties of the overall mix- matic phase, depends not only on the absolute molecular
ture. This behaviour can be quantified by so-called “vir- dipole moment, µ, but also on the orientation of the dipole
tual” parameters, such as the clearing point (T NI,virt), the moment vector relative to the director of the nematic phase,
dielectric anisotropy (∆εvirt), and birefringence (∆nvirt),[8] which can be approximated by the long molecular axis.[9,10]
which are summarized in Table 1.
An orientation of the molecular dipole moment vector ex-
actly parallel to the long molecular axis is most effective for
achieving a high dielectric anisotropy in the nematic phase.
More oblique orientations result in reduced or even nega-
tive ∆ε values.
The sulfoximide 7 can assume three basic conformers,
which are interchangeable by a threefold rotation around
the nitrogen–sulfur single bond. Their relative energies are
estimated to be within a range of 2.8 kcal mol–1 (Fig-
ure 1).[11] In the energetically preferred conformer (B,
0 kcal mol–1), the local dipole moment of the terminal tri-
fluoromethyl moiety is pointing roughly perpendicular to
the long molecular axis of the liquid crystal. Further rota-
tion around the central nitrogen–sulfur bond gives the other
conformers, A with similar energy (0.2 kcal mol–1) and C
with a significantly higher energy (2.8 kcal mol–1), neither
Table 1. Physical properties of the liquid crystals 3–7.[8] Due to its
limited solubility in the nematic host mixture ZLI-4792, the virtual
parameters for sulfone 5 were only extrapolated from a 5% w/w
solution. The solubility for sulfoximide 6 was too low to obtaining
extrapolated mixture data. The melting points and virtual clearing
temperatures are given in degrees Celsius.
M.p.
TNI,virt
∆εvirt
∆nvirt
3
4
5
6
7
69
101
146
166
101
27.6
32.5
14.4
–
9.8
0.086
0.098
0.100
–
16.4
25.8
–
–14.9
20.0
0.141
As expected, the dielectric anisotropy (∆εvirt) of the mate- of which has its dipole moment oriented in the direction of
rials 3–5 increases with the oxidation state of sulfur. Due the long molecular axis. The absolute dipole moments of
to the poor solubility of the sulfoximide 6, no meaningful all three conformers are rather high (around 8.2 D)[11] and
data could be extrapolated from the nematic host mixture quite similar. Nevertheless, their oblique orientation relative
ZLI-4792.[8] Interestingly, the dielectric anisotropy of sul- to the long molecular axis of the liquid crystal is the main
foximide 7 is significantly lower than that of the sulfone 5 reason for the lower than expected dielectric anisotropy
in spite of the far stronger electron-withdrawing character of 7.
798
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Highly Fluorinated Sulfimides and Sulfoximides
FULL PAPER
Figure 1. The three major conformers of 2,6-difluoro-1-[S-trifluoromethyl-N-(trifluoromethylsulfonyl)sulfoximido]benzene as a simplified
model for the polar head-group of the liquid crystal 7 (B3LYP/6-31G*//B3LYP/6-31G* level of theory),[11] a schematic representation of
the equilibrium between the three conformers A (0.2 kcal mol–1), B (0 kcal mol–1) and C (2.8 kcal mol–1) and the different orientation of
their dipole moments relative to the long molecular axis of the liquid crystal.
Synthesis and Characterization of the Model Compounds
seem to play a dominant role for the stabilization of the
In order to explore and extend the scope of our synthetic structure: in one dimension PhF5-PhF5-Ph triads are a re-
methodology, a study was conducted with the aim to pre- current motif (Figure 2).[2,14] The two pentafluorophenyl
pare compounds 8 and 9 as models for other structural mo- rings are parallel and eclipsed with an interplanar distance
tifs that are of potential interest for organic materials’ de- of about 3.6 Å. In the phenyl-pentafluorophenyl pair the
sign. There have been several reports on different synthetic rings are roughly parallel, with a distance of around 3.4 Å,
routes leading to the basic N,S,S-triphenyl sulfimide struc- but are shifted relative to each other.
ture,[12] but none of them uses the convenient activation of
All the aromatic and pentafluoroaromatic moieties are
diphenyl sulfoxide (10) in situ. In analogy to the synthesis oriented parallel to two of the three crystallographic planes,
of 6 with triflic amide as the nucleophilic component, with all pentafluorophenyl residues in the crystal coplanar
pentafluoroaniline acts here as the nucleophile (Scheme 2). with only one of these planes.
In contrast to 6, however, the resulting N-(pentafluorophe-
The structure of the single molecules of 9 (Figure 3) is
nyl)-S,S-diphenylsulfimide (8) is hydrolytically unstable, very similar to that of 8, and the space group is the same
¯
and the work-up has therefore to be done under neutral (P1). In one dimension, parallel but shifted PhF5-Ph pairs
or mildly basic conditions. Oxidation to the corresponding with a greater interplanar distance of 3.9 Å are apparently
sulfoximide 9 can be achieved under the same conditions as stabilizing the arrangement. Again, all pentafluorophenyl
for 7.
moieties are coplanar with only one crystallographic plane,
For both compounds 8 and 9 it was possible to obtain and all the aromatic and fluoroaromatic moieties are paral-
single crystals suitable for X-ray crystallography from a lel to only two of the three planes.
solution in n-heptane.[13] Both molecules have a T-like
A detailed study of the gas-phase ion chemistry and pro-
shape with a planar Ph–S=N–PhF5 subunit as the top bar ton affinities of the two model compounds 8 and 9 by FT-
and one phenyl moiety perpendicular (Figure 1 and Fig- ICR mass spectrometry will be the subject of a forthcoming
ure 2). Arene–arene interactions in the crystal packing of 8 publication.[15]
Scheme 2. Synthesis of compounds 8 and 9: a) 1. Tf2O, CH2Cl2, –70 °C, 1 h. 2. pentafluoroaniline, CH2Cl2, –70 °C to room temp. (62%);
b) NaIO4, RuCl3 (0.1 mol%), CH3CN, CCl4, H2O, room temp., 3 d (34%).
Eur. J. Org. Chem. 2005, 797–802
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© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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P. Kirsch, M. Lenges, D. Kühne, K.-P. Wanczek
FULL PAPER
[13]
Figure 2. X-ray structure of 8
showing two views of the single molecule, one frontal of the T-like shape (top left), and one of the Ph-
S=N-PhF5 heterostilbene-like substructure (bottom left) with one S-phenyl moiety pointing away from the viewer. The packing model
on the right indicates a stabilization of the arrangement by arene–arene interactions, particularly by PhF5-PhF5-Ph triads.
[13]
Figure 3. X-ray structure of 9
showing two views of the single molecule, one frontal of the T-like shape (top left), and one of the Ph-
S=N-PhF5 heterostilbene-like substructure (bottom left) with one S-phenyl moiety pointing away from the viewer. As for 8, the packing
model on the right indicates a stabilization of the arrangement by arene–arene interactions, although here by PhF5-Ph dimers.
Conclusions
An improved synthetic methodology has been developed 9 demonstrates how supramolecular arrangements can be
that allows the convenient preparation of highly fluorinated stabilized by electrostatic arene–perfluoro-arene interac-
sulfimides and sulfoximides. This method was subsequently tions.
applied to the synthesis of the highly polar, fluorinated li-
These results indicate the potential usefulness of sulfoxi-
quid crystals 6 and 7. The syntheses of 8 and 9 illustrate the mide-based functional materials in particular in electrically
general scope of the method and its applicability for the passive devices, such as LCDs, as well as in active devices,
synthesis of structural motifs of interest for organic materi- such as organic light-emitting diodes (OLED) or organic
als. The crystal packing of the T-shaped molecules of 8 and field-effect transistors (OFET).
800
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Eur. J. Org. Chem. 2005, 797–802

Highly Fluorinated Sulfimides and Sulfoximides
FULL PAPER
10 mL of acetonitrile, 10 mL of CCl4 and 20 mL of water was
stirred at room temperature for 3 d. The solution was extracted
three times with 100 mL of methyl tert-butyl ether, the combined
organic phases were dried with Na2SO4, and the solvents evapo-
rated to dryness. The crude product was chromatographed over
silica gel (toluene) and subsequently crystallized once from ethanol
and once from n-heptane to yield 420 mg (34 %) of pure 9 as
slightly yellowish crystals, m.p. 105.6 °C (purity 99.8% by HPLC).
1H NMR (250 MHz, CDCl3): δ = 7.53 (mc, 6 H, ar-H), 8.05 (mc,
4 H, ar-H) ppm. 13C NMR (75 MHz, CDCl3): δ = 128.1, 129.3,
133.1, 140.3 ppm. 19F NMR (235 MHz, CDCl3; standard CFCl3):
δ = –164.9 (mc, 1 F, ar-F), –164.3 (mc, 2 F, ar-F), –148.1 (mc, 2 F,
ar-F) ppm. MS (EI, 70 eV): m/z (%) = 383 (100) [M+], 258 (55),
238 (19), 202 (17), 186 (30), 173 (11), 154 (39), 125 (27), 97 (26).
HRMS for [M]+ (C18H10F5NOS): calcd. 383.0403, found 383.0407.
Experimental Section
N-(Trifluoromethylsulfonyl)sulfimide
(6):
Triflic
anhydride
(2.02 mL, 12 mmol) and then, 10 min later, trifluoromethane sul-
fonamide (2.24 g, 15 mmol) were added to a solution of 4 (4.37 g,
10 mmol) in 20 mL of CH2Cl2 whilst maintaining the temperature
of the mixture at room temperature. After stirring at this tempera-
ture for 18 h, the mixture was poured into 200 mL of ice-water and
extracted three times with 30 mL of CH2Cl2. The combined ex-
tracts were washed with saturated aqueous NaHCO3 solution, with
water and brine, and subsequently dried with MgSO4. After evapo-
ration to dryness, the crude product was chromatographed (n-hep-
tane/ethyl acetate, 50:1) on silica gel and crystallized once from n-
heptane. Yield: 0.9 g (16 %), colourless crystals, m.p. 166 °C (purity
1
99.7% by HPLC). H NMR (250 MHz, CDCl3): δ = 0.89 (t, J =
7.3 Hz, 3 H), 0.90–1.47 (m, 15 H), 1.68–1.81 (m, 4 H), 1.86–2.01
(m, 4 H), 2.5–2.63 (m, 1 H), 7.04 (d, J = 8.8 Hz, 2 H) ppm. 19F
NMR (235 MHz, CDCl3; standard CFCl3): δ = –102.8 (mc, 2 F,
ar-F), –78.1 (mc, 3 F, NSO2CF 3), –63.1 (mc, 3 F, SCF 3) ppm. MS
(EI, 70 eV): m/z (%) = 498 (100) [M+ – CF3], 420 (11), 240 (7),
159 (9), 123 (10), 109 (13), 95 (8). HRMS for [M+ – CF3]
Acknowledgments
We are indebted to I. Svoboda (Technical University of Darmstadt,
group of Prof. Dr. Fuess) for the X-ray structures. Dr. Matthias
Bremer is thanked for his valuable advice on the computational
chemistry.
(C22H29F5NO2S2):
calcd.
498.1560;
found
498.1572.
C23H29F8NO2S2 (567.6): calcd. C 48.2, H 5.2, N 2.3, S 10.7; found
C 48.6, H 4.9, N 2.3, S 10.4.
[1] N. V. Kondratenko, V. I. Popov, G. N. Timofeeva, N. V. Ignat-
iev, L. M. Yagupolskii, J. Org. Chem. USSR 1985, 21, 2367–
2371; Chem. Abstr. 1985, 102, 220513.
[2] For an overview on the substituent effects of different fluori-
nated functional groups, see: P. Kirsch, Modern Fluoroorganic
Chemistry: Synthesis, Reactivity, Applications, Wiley-VCH,
Weinheim, Germany, 2004, p. 239.
[3] N. V. Kondratenko, V. I. Popov, O. A. Radchenko, N. V. Ignat-
iev, L. M. Yagupolskii, J. Org. Chem. USSR 1987, 23, 1542–
1547; Chem. Abstr. 1987, 107, 39309.
[4] a) L. M. Yagupolskii, R. Yu. Garlyauskajte, N. V. Kondrat-
enko, Synthesis 1992, 749–750; b) R. Yu. Garlyauskajte, S. V.
Sereda, L. M. Yagupolskii, Tetrahedron 1994, 50, 6891–6906.
[5] P. Kirsch, M. Bremer, Angew. Chem. 2000, 112, 4384–4405; An-
gew. Chem. Int. Ed. 2000, 39, 4216–4235.
N-(Trifluoromethylsulfonyl)sulfoximide (7): A mixture of 6 (800 mg,
1.41 mmol), NaIO4 (900 mg 4.21 mmol), RuCl3·H2O (10 mg),
4 mL of acetonitrile, 4 mL of CCl4 and 8 mL of water was stirred
at room temperature for 3 d. The solution was extracted three times
with 50 mL of methyl tert-butyl ether, the combined organic phases
were dried with Na2SO4, and the solvents evaporated to dryness.
The crude product was chromatographed over silica gel (n-heptane/
toluene, 1:1) and subsequently crystallized once from ethanol and
once from n-heptane to yield 340 mg (41 %) of pure 7 as colourless
crystals, m.p. 101 °C (purity 99.5% by HPLC). 1H NMR
(250 MHz, CDCl3): δ = 0.88 (t, J = 7.3 Hz, 3 H), 0.93–1.48 (m, 15
H), 1.70–1.80 (m, 4 H), 1.89–1.99 (m, 4 H), 2.53–2.63 (m, 1 H),
7.07 (d, J = 9.7 Hz, 2 H) ppm. 19F NMR (235 MHz, CDCl3;
standard CFCl3): δ = –101.0 (mc, 2 F, ar-F), –78.9 (mc, 3 F,
NSO2CF ), –76.5 (mc, 3 F, SCF ) ppm. MS (EI, 70 eV): m/z (%)
[6] a) J. H. Clark, C. W. Jones, A. P. Kybett, M. A. McClinton, J.
Fluorine Chem. 1990, 48, 249–253; b) L. M. Yagupolskii, N. V.
Kondratenko, V. P. Sambur, Synthesis 1975, 721–723.
[7] W. Su, Tetrahedron Lett. 1994, 35, 4955–4958.
3
3
= 583 (30) [M+], 563 (5), 514 (6), 203 (10), 125 (55), 83 (68), 69
(100).
[8] A major part of the application-oriented characterization of
N-(Pentafluorophenyl)-S,S-diphenylsulfimide (8): A solution of 10
(3.0 g, 14 mmol) in 20 mL of CH2Cl2 was treated dropwise with
triflic anhydride (2.6 mL 15 mmol) at –70 °C. After 1 h, a solution
of pentafluoroaniline (4.0 g, 21 mmol) in 50 mL of CH2Cl2 was
added dropwise at the same temperature. The mixture was stirred
at –70 °C for 1 h and then warmed up to room temperature over
4 h. The mixture was then poured into 500 mL of saturated aque-
ous NaHCO3 solution. The organic phase was separated, and the
aqueous phase was extracted twice with 100 mL of CH2Cl2. The
combined organic phases were dried with Na2SO4 and the solvents
evaporated to dryness. The crude product was chromatographed
over silica gel (toluene) and subsequently crystallized once from
ethanol and once from n-heptane to yield 3.5 g (62 %) of pure 8 as
yellowish crystals, m.p. 79.6 °C (purity 99.8% by HPLC). 1H NMR
(250 MHz, CDCl3): δ = 7.50 (mc, 6 H, ar-H), 7.78 (mc, 4 H, ar-H)
ppm. 13C NMR (75 MHz, CDCl3): δ = 126.5, 129.5, 131.4, 140.5
ppm. 19F NMR (235 MHz, CDCl3; standard CFCl3): δ = –172.6
(mc, 1 F, ar-F), –166.7 (mc, 2 F, ar-F), –156.0 (mc, 2 F, ar-F) ppm.
MS (EI, 70 eV): m/z (%) = 367 (8) [M+], 258 (7), 186 (100), 109 (6),
97 (5), 77 (13).
liquid crystals is based on the “virtual” parameters TNI,virt
,
∆εvirt and ∆nvirt, which are determined by linear extrapolation
from a 10% w/w solution in the commercially available Merck
mixture ZLI-4792 (TNI = 92.8 °C, ∆ε = 5.3, ∆n = 0.0964). The
extrapolated values are corrected empirically for differences in
the order parameter that are induced by the analyte. For the
pure substances, the melting points were identified by DSC.
[9] For the relation between the molecular dipole moment and the
dielectric anisotropy (∆ε) of the nematic phase, see: a) W. Ma-
ier, G. Meier, Z. Naturforsch.Teil A 1961, 16, 262–267; b) D.
Demus, G. Pelzl, Z. Chem. 1982, 21, 1; c) J. Michl, E. W.
Thulstrup, “Spectroscopy with Polarized Light: Solute Align-
ment by Photoselection”, in Liquid Crystals, Polymers, and
Membranes, Wiley-VCH, Weinheim, 1995, p. 171–221.
[10] For the prediction of the dielectric anisotropy (∆ε) and birefrin-
gence (∆n) of nematic liquid crystals, see: a) M. Bremer, K.
Tarumi, Adv. Mater. 1993, 5, 842–848; b) M. Klasen, M.
Bremer, A. Götz, A. Manabe, S. Naemura, K. Tarumi, Jpn. J.
Appl. Phys. 1998, 37, L945–L948.
[11] a) Calculations: Gaussian 98, Revision A.6: M. J. Frisch, G. W.
Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Chee-
seman, V. G. Zakrzewski, J. A. Montgomery, Jr., R. E. Strat-
mann, J. C. Burant, S. Dapprich, J. M. Millam, A. D. Daniels,
K. N. Kudin, M. C. Strain, O. Farkas, J. Tomasi, V. Barone,
N-(Pentafluorophenyl)-S,S-diphenylsulfoximide (9): A mixture of 8
(1.2 g, 3.2 mmol), NaIO4 (2.14 g, 10 mmol), 30 mg of RuCl3 ·H2O,
Eur. J. Org. Chem. 2005, 797–802
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P. Kirsch, M. Lenges, D. Kühne, K.-P. Wanczek
FULL PAPER
M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S.
Clifford, J. Ochterski, G. A. Petersson, P. Y. Ayala, Q. Cui, K.
Morokuma, D. K. Malick, A. D. Rabuck, K. Raghavachari,
J. B. Foresman, J. Cioslowski, J. V. Ortiz, B. B. Stefanov, G.
Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts,
R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng,
A. Nanayakkara, C. Gonzalez, M. Challacombe, P. M. W. Gill,
B. Johnson, W. Chen, M. W. Wong, J. L. Andres, C. Gonzalez,
M. Head-Gordon, E. S. Replogle, and J. A. Pople, Gaussian,
Inc., Pittsburgh, PA, USA, 1998. The energies of the conform-
ers A, B, and C were calculated at the B3LYP/6-31G*//B3LYP/
6-31G* level of theory, including zero point energy correction.
b) Pictures: MOLEKEL 4.2: P. Flükinger, H. P. Lüthi, S. Port-
mann, J. Weber, Swiss Center for Scientific Computing,
Manno, Switzerland, 2002.
[13] a) Crystal structure data for 8: C182H10F5NS, crystallization
¯
from n-heptane: triclinic, P1,
a
=
8.1970(10) Å,
105.180(10)°,
b
=
=
9.2450(10) Å,
c
=
11.038(2) Å,
α
=
β
93.350(10)°, γ = 106.080(10)°, V = 767.93(19) Å3, Z = 2, ρ calcd.
= 1.589 g cm–1, R(F) = 4.90% for 3075 observed independent
reflections (4.35° Յ θ Յ 26.37°); b) Crystal structure data for
¯
9: C18H10F5NOS, crystallization from n-heptane: triclinic, P1,
a = 8.0797(7) Å, b = 9.4506(8) Å, c = 10.5817(9) Å, α =
99.177(7)°, β = 91.672(7)°, γ = 93.878(7)°, V = 795.17(12) Å3,
Z = 2, ρcalcd. = 1.601 g cm–1, R(F) = 5.55% for 4096 observed
independent reflections (3.16° Յ θ Յ 30.05°); c) CCDC-242383
(8) and -242384 (9) contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
[12] a) Reaction of S,S-difluoro-N-phenylsulfimide with phenyllith-
ium: W. C. Smith, US 2862029, 1958; Chem. Abstr. 1959, 53,
51019; b) Reaction of Martin sulfurane dehydration reagent
with aniline: J. A. Franz, J. C. Martin, J. Am. Chem. Soc. 1975,
97, 583–589; c) Reaction of S,S-diphenylsulfimide with an acti-
vated haloarene: M. Abou-Gharbia, D. M. Ketcha, D. E. Za-
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[14] For a detailed discussion on arene–perfluoroarene interactions,
see: E. A. Meyer, R. K. Castellano, F. Diederich, Angew. Chem.
2003, 115, 1244–1287; Angew. Chem. Int. Ed. 2003, 42, 1210–
1250.
[15] K.-P. Wanczek, D. Kühne, M. Lenges, P. Kirsch, manuscript in
preparation.
Received October 6, 2004
802
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