Dispiro[fluorene-9,5′-[1,2,3,4]tetrathiane-6′, 9″-fluorene]

Article abstract of DOI:10.1107/S0108270101005248

The tetrathiane ring of the title compound, C₂₆H₁₆S₄, has a chair conformation and the molecule has approximate C₂ symmetry. Each of the two fluorene ring systems is virtually planar, with the ring planes intersecting at an angle of 67.58 (5)°. This novel compound has been formed as a side product from the treatment of 9H-fluorene-9-thione with methyl N-[(benzylidene)phenyl]glycinate in the presence of LiBr and 1,6-diazabicyclo[5.4.0]undecane.

Full text of DOI:10.1107/S0108270101005248

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
Â
reacting 1,2-dithiols with dichlorodisulfane (S2Cl2; Feher &
Degen, 1967; Feher et al., 1972a,b; Kustos & Stendel, 1995).
Â
Different approaches have been developed by heating alkenes
with polysul®des (Krespan & Brasen, 1962), with sulfur (S8)
and catalysts (Chernyshev et al., 1984; Nekhaev et al., 1991) or
by treatment of thiiranes with catalytic amounts of tris(4-
bromophenyl)aminium hexachloroantimonate, an aminium
radical salt, in dichloromethane, the latter reaction occurring
via an SET mechanism (Kamata et al., 1990).
ISSN 0108-2701
Dispiro[fluorene-9,50-[1,2,3,4]tetra-
thiane-60,900-fluorene]
Recently, we became interested in the reaction of azo-
methine ylides with C S compounds (Mloston et al., 1998;
Gebert, 2001; Gebert et al., 2001). Among the different known
routes for synthesizing reactive azomethine ylides, we
followed a protocol that starts with N-benzylidene-ꢀ-amino
acid esters in the presence of LiBr and 1,6-diazabi-
cyclo[5.4.0]undecane (DBU) as the base (Grigg & Sridharan,
1993; Kanemasa & Tsuge, 1993; Barr et al., 1995). In the case
of methyl N-[(benzylidene)phenyl]glycinate, (I), and 9H-
¯uorene-9-thione, (II), the reaction at room temperature was
terminated after two minutes. In addition to the two
diastereoisomeric cycloadducts of type (III), which were
isolated in 82% yield (cis/trans ratio 2.4:1) (Gebert et al.,
2001), small amounts of 9H-¯uoren-9-one, dispiro[¯uorene-
9,50-[1,2,3,4]tetrathiane-60,900-¯uorene], (IV), and ole®n (V)
were isolated after chromatography. Whereas 9H-¯uoren-9-
one and the ole®n (V) are well known side products in reac-
tions involving (II), the tetrathiane (IV) has never been
observed before. The latter was obtained in 1±3% yield after
crystallization and, as part of the full characterization of this
compound, its low-temperature crystal structure has been
determined.
Anthony Linden,* Andreas Gebert and Heinz Heimgartner
Institute of Organic Chemistry, University of Zurich, Winterthurerstrasse 190,
È
CH-8057 Zurich, Switzerland
È
Correspondence e-mail: alinden@oci.unizh.ch
Received 22 March 2001
Accepted 26 March 2001
The tetrathiane ring of the title compound, C26H16S4, has a
chair conformation and the molecule has approximate C2
symmetry. Each of the two ¯uorene ring systems is virtually
planar, with the ring planes intersecting at an angle of
67.58 (5)ꢁ. This novel compound has been formed as a side
product from the treatment of 9H-¯uorene-9-thione with
methyl N-[(benzylidene)phenyl]glycinate in the presence of
LiBr and 1,6-diazabicyclo[5.4.0]undecane.
Comment
For many years we have been investigating reactions involving
compounds containing C S groups, for example, thioketones
and 1,3-thiazole-5(4H)-thiones (Heimgartner, 1986, 1991;
Mloston & Heimgartner, 2000). The focus of our studies is on
1,3-dipolar cycloadditions which lead to new sulfur hetero-
cycles. Among the 1,3-dipoles that have been used are nitrile
È
ylides (Buchel et al., 1984), nitrile imines (Linden et al., 1999),
azides (Mloston & Heimgartner, 1995; Mloston et al., 1996),
È
diazo compounds (Kagi et al., 1996; Kelmendi et al., 2000),
carbonyl ylides (Meier et al., 1997) and thiocarbonyl ylides
(Mloston & Heimgartner, 2000). In some cases, such as with
azides and diazo compounds under forced conditions,
elemental sulfur was formed (`twofold extrusion'; Guziec &
San®lippo, 1988), which led to the formation of products
containing more than one S atom per molecule. As an
example, reactions of reactive thiocarbonyl compounds, such
as thiobenzophenone or 9H-¯uorene-9-thione, with phenyl
azide yielded the corresponding N-phenylimines and 1,2,4-
trithiolanes (Mloston & Heimgartner, 1995; cf. Fabian &
Senning, 1998). The intermediate formation of a thiosul®ne
(thiocarbonyl-S-sul®de) via sulfur transfer and a subsequent
1,3-dipolar cycloaddition is proposed as the reaction
mechanism. Thiosul®nes, which can also be generated by
thiation of thiocarbonyl compounds with S8, can dimerize to
give 1,2,4,5-tetrathianes (Franek, 1991a,b; Huisgen & Rapp,
1997; Huisgen et al., 1997; cf. Senning, 1994).
The molecule of compound (IV) has approximate C2
symmetry, with an r.m.s. deviation of the related atoms of
Ê
0.14 A. The C2 axis is not parallel to any of the unit-cell axes.
The 1,2,3,4-tetrathiane ring has a slightly distorted chair
conformation, with puckering parameters (Cremer & Pople,
ꢁ
ꢁ
Ê
1975) of Q = 0.927 (1) A, ꢁ = 13.4 (1) and ' = 85.3 (4) for the
atom sequence S1, S2, S3, S4, C14 and C1. Ideally, ꢁ would be
equal to 0ꢁ for a perfect chair and the distortions can be
attributed to the heteroatomic nature of the ring. Each of the
two ¯uorene ring systems is nearly planar, although the phenyl
rings are inclined very slightly from the plane to form a ¯at
dish-shaped moiety. In the ¯uorene group de®ned by atoms
C1±C13, the r.m.s. deviation of these atoms from their mean
Cyclic polysul®des are a highly interesting class of sulfur
heterocycles (cf. Block et al., 1988; Sato et al., 2001). Among
them, several 1,2,3,4-tetrathianes have been prepared by
ꢀ
764 # 2001 International Union of Crystallography
Printed in Great Britain ± all rights reserved
Acta Cryst. (2001). C57, 764±766

organic compounds
Ê
Ê
Â
plane is 0.034 A, with a maximum deviation of 0.060 (2) A for
C3. The angle between the two phenyl ring planes is 3.91 (18)ꢁ.
In the second ¯uorene moiety, the r.m.s. deviation of atoms
tetrathiadecalin (Feher et al., 1972a). In each case, the tetra-
thiane ring adopts a slightly distorted chair conformation and
the bond lengths and angles around the ring are in close
agreement with those observed for compound (IV) (Table 1).
For all four compounds, the intra-ring angles involving S
atoms are several degrees smaller than the ideal tetrahedral
angle, with the SÐSÐS angles being the smallest, while those
involving C atoms are slightly larger than the ideal tetrahedral
angle. Such distortions are consistent with the ring strain
introduced by the presence of two elements with signi®cantly
different covalent radii in the ring.
Ê
C14±C26 from their mean plane is 0.060 A, with a maximum
Ê
deviation of 0.104 (2) A for C17, and the angle between the
two phenyl ring planes is 6.49 (15)ꢁ. The mean planes of the
two ¯uorene ring systems intersect at an angle of 67.58 (5)ꢁ.
Atoms C3 and H3 have short intramolecular contacts with
S2 and S4, while atoms C25 and H25 have similar contacts with
Ê
S1 and S3 (Table 2). These contacts are only 0.06±0.15 A
shorter than the sum of the van der Waals radii of the
respective atoms and it may be inappropriate to describe them
as weak hydrogen-bonding interactions because the CÐHÁ Á ÁS
angles are less than 120ꢁ. Distortions in the conformation of
the molecule suggest that the contacts probably cause repul-
sive interactions and that the lack of suf®cient conformational
¯exibility in the molecule prevents these atoms from being
able to increase their interatomic separation any further. The
C3ÐH3 bond nestles neatly between S2 and S4 of the 1,2,3,4-
tetrathiane ring and is virtually equidistant from these S
atoms. In this position and in the absence of steric strain, C3
and H3 would come too close to S2 and S4. The repulsive
interactions cause the ¯uorene ring to be tipped back slightly
on its C2ÐC1ÐC13 pivot, so that the plane de®ned by S1, C1
and C14 does not intersect the C7ÐC8 bond at its midpoint,
but at a point much closer to C7. The distances of C7 and C8
from this plane are 0.451 (10) and 1.003 (10) A, respectively.
The interactions of C25 and H24 with S1 and S3 cause the
second ¯uorene moiety to be tipped in a similar manner, with
Ê
C21 and C20 being 0.435 (10) and 1.019 (10) A, respectively,
from the plane de®ned by C1, C14 and S4.
The Cambridge Structural Database (CSD, October 2000
release; Allen & Kennard, 1993) cites three structures
containing 1,2,3,4-tetrathiane rings, these being simply
substituted derivatives, namely 1,1-dimethylsila-4,5,6,7-tetra-
thiabicyclo[4.3.0]nonane (Chernyshev et al., 1984), trans-5,6-
diphenyl-1,2,3,4-tetrathiane (Kamata et al., 1990) and 1,2,3,4-
Experimental
The title compound, (IV), was obtained in 1±3% yield by
reacting methyl N-[(benzylidene)phenyl]glycinate, (I)
(253 mg, 1.0 mmol), with 9H-¯uorene-9-thione, (II) (394 mg,
2.0 mmol), in a mixture of acetonitrile (5 ml) and toluene
(1 ml) for 2 min at room temperature. After chromatography
(silica gel, hexane/ethyl acetate 30:1) and crystallization from
chloroform/hexane, (IV) was isolated as colourless prisms
(m.p. 445±449 K). Suitable single crystals of (IV) were
obtained by recrystallization from chloroform/hexane.
Crystal data
3
C26H16S4
Mr = 456.65
Dx = 1.484 Mg m
Mo Kꢀ radiation
Ê
Orthorhombic, Pbcn
Ê
Cell parameters from 22 re¯ections
ꢁ = 15.0±20.0ꢁ
ꢂ = 0.48 mm
T = 173 (1) K
Prism, colourless
0.45 Â 0.25 Â 0.25 mm
a = 13.510 (3) A
Ê
1
b = 18.014 (7) A
Ê
c = 16.795 (5) A
3
Ê
V = 4087 (2) A
Z = 8
Data collection
Rigaku AFC-5R diffractometer
!±2ꢁ scans
Absorption correction: scan
Rint = 0.038
ꢁmax = 27.5ꢁ
h = 1 ! 17
(North et al., 1968) Tmin
0.833, Tmax = 0.888
5956 measured re¯ections
=
k = 1 ! 23
l = 21 ! 0
3 standard re¯ections every 150
re¯ections intensity decay: none
4685 independent re¯ections
3074 re¯ections with I > 2ꢃ(I)
Re®nement
Re®nement on F2
R[F2 > 2ꢃ(F2)] = 0.042
wR(F2) = 0.116
S = 1.02
4685 re¯ections
271 parameters
H-atom parameters constrained
w = 1/[ꢃ2(Fo2) + (0.0489P)2 +
1.1375P] where P = (Fo2 + 2Fc2)/3
(Á/ꢃ)max = 0.001
3
Ê
Áꢄmax = 0.34 e A
3
Ê
0.38 e A
Áꢄmin
=
Table 1
Selected geometric parameters (A, ).
ꢁ
Ê
S1ÐC1
S1ÐS2
S2ÐS3
S3ÐS4
S4ÐC14
1.863 (3)
C1ÐC2
1.530 (3)
1.534 (4)
1.576 (3)
1.538 (4)
1.532 (4)
2.0534 (11)
2.0585 (13)
2.0546 (11)
1.867 (3)
C1ÐC13
C1ÐC14
C14ÐC15
C14ÐC26
Figure 1
C1ÐS1ÐS2
S1ÐS2ÐS3
S2ÐS3ÐS4
104.77 (9)
100.06 (4)
100.43 (4)
S3ÐS4ÐC14
S1ÐC1ÐC14
S4ÐC14ÐC1
105.04 (9)
113.28 (17)
114.43 (18)
View of the molecule of the title compound, (IV), showing the atom-
labelling scheme. Displacement ellipsoids are drawn at the 50%
probability level. H atoms are represented by circles of arbitrary size.
ꢀ
Acta Cryst. (2001). C57, 764±766
Anthony Linden et al. C26H16S4 765

organic compounds
Â
Feher, F., Klaeren, A. & Linke, K.-H. (1972a). Acta Cryst. B28, 534±537.
Table 2
Intramolecular contact geometry (A, ).
ꢁ
Ê
Â
Feher, F., Langer, M. & Volkert, R. (1972b). Z. Naturforsch. Teil B, 27, 1006±
1007.
Franek, W. (1991a). Sulfur Rep. 10, 193±232.
Franek, W. (1991b). Sulfur Rep. 10, 233±278.
Gebert, A. (2001). PhD thesis, University of Zurich, Switzerland.
Gebert, A., Linden, A. & Heimgartner, H. (2001). Heterocycles, 54, 691±704.
Grigg, R. & Sridharan, V. (1993). Adv. Cycloaddition, 3, 161±204.
Guziec, F. S. & San®lippo, L. J. (1988). Tetrahedron, 44, 6241±6285.
Heimgartner, H. (1986). Croat. Chem. Acta, 59, 237±265.
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
È
C3ÐH3Á Á ÁS2
C3ÐH3Á Á ÁS4
C25ÐH25Á Á ÁS1
C25ÐH25Á Á ÁS3
0.95
0.95
0.95
0.95
2.92
2.85
2.87
2.89
3.436 (3)
3.396 (3)
3.405 (3)
3.429 (3)
115
118
117
117
Heimgartner, H. (1991). Phosphorus Sulfur Silicon, 58, 281±293.
Huisgen, R. & Rapp, J. (1997). Heterocycles, 45, 507±525.
Huisgen, R., Rapp, J. & Huber, H. (1997). Liebigs Ann. Recl, pp. 1517±1523.
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National
Laboratory, Tennessee, USA.
Data collection: MSC/AFC Diffractometer Control Software (Mole-
cular Structure Corporation, 1991); cell re®nement: MSC/AFC
Diffractometer Control Software; data reduction: TEXSAN (Mole-
cular Structure Corporation, 1999); program(s) used to solve struc-
ture: SHELXS86 (Sheldrick, 1990); program(s) used to re®ne
structure: SHELXL97 (Sheldrick, 1997); molecular graphics:
ORTEPII (Johnson, 1976); software used to prepare material for
publication: SHELXL97.
È
Kagi, M., Linden, A., Mloston, G. & Heimgartner, H. (1996). Helv. Chim. Acta,
79, 855±874.
Kamata, M., Murayama, K., Suzuki, T. & Miyashi, T. (1990). J. Chem. Soc.
Chem. Commun. pp. 827±829.
Kanemasa, S. & Tsuge, O. (1993). Adv. Cycloaddition, 3, 99±159.
Kelmendi, B., Mloston, G. & Heimgartner, H. (2000). Heterocycles, 52, 475±
482.
Krespan, C. G. & Brasen, W. R. (1962). J. Org. Chem. 27, 3995±4000.
Kustos, M. & Stendel, R. (1995). J. Org. Chem. 60, 8056±8061.
Linden, A., Awad, E. M. A. H. & Heimgartner, H. (1999). Acta Cryst. C55,
1877±1881.
Meier, K.-R., Linden, A., Mloston, G. & Heimgartner, H. (1997). Helv. Chim.
Acta, 80, 1190±1204.
The Swiss National Science Foundation and F. Hoffmann±
La Roche AG, Basel, are thanked for ®nancial support.
Mloston, G. & Heimgartner, H. (1995). Helv. Chim. Acta, 78, 1298±1310.
Mloston, G. & Heimgartner, H. (2000). Pol. J. Chem. 74, 1503±1532.
Mloston, G., Linden, A. & Heimgartner, H. (1998). Helv. Chim. Acta, 81, 558±
569.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: NA1515). Services for accessing these data are
described at the back of the journal.
Mloston, G., Romanski, J. & Heimgartner, H. (1996). Pol. J. Chem. 70, 437±
445.
Molecular Structure Corporation (1991). MSC/AFC Diffractometer Control
Software. MSC, 3200 Research Forest Drive, The Woodlands, TX 77381,
USA. (Current address: MSC, 9009 New Trails Drive, The Woodlands, TX
77381±5209, USA.)
Molecular Structure Corporation (1999). TEXSAN. Version 1.10b. MSC, 9009
New Trails Drive, The Woodlands, TX 77381±5209, USA.
Nekhaev, A. I., Kolobkov, B. I., Toshev, M. T., Dustov, K. B. & Aleksandrov,
G. G. (1991). Bull. Acad. Sci. USSR Div. Chem. Sci. 40, 827±830.
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351±
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766 Anthony Linden et al.
C26H16S4
Acta Cryst. (2001). C57, 764±766