1,1′-(Ethenylidene)bis(4-chlorobenzene)

Article abstract of DOI:10.1107/S0108270106040753

The title compound, C₁₄H₁₀Cl₂, crystallizes as colourless prisms with two symmetry-independent molecules in the unit cell. Numerous intermolecular C-H...π interactions dominate in the crystal structure, where C-H...Cl and long Cl...Cl contacts are also observed.

Full text of DOI:10.1107/S0108270106040753

organic compounds
Acta Crystallographica Section C
Crystal Structure
paper, the crystal structure of DDNU is reported in compar-
ison with those of DDT and its metabolites.
Communications
ISSN 0108-2701
1,10-(Ethenylidene)bis(4-chloro-
benzene)
Md. Abdul Jabbar, Isao Aritome, Hisashi Shimakoshi and
Yoshio Hisaeda*
Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu
University, Motooka 744, Nishi-ku, Fukuoka 819-0395, Japan
Correspondence e-mail: yhisatcm@mbox.nc.kyushu-u.ac.jp
DDNU crystallizes as colourless prisms with two symmetry-
independent molecules, denoted 1 and 2, in the asymmetric
unit (Fig. 1). The two independent molecules are an approx-
imate inverted image of each other, although the aryl rings
cannot be superimposed exactly. The dihedral angles between
the two aryl planes are 63.59 (11) and 63.86 (10)ꢀ for mol-
ecules 1 and 2, respectively, and the aryl rings are not related
by symmetry, while in DDT and its analogues there is mirror
symmetry between the two aryl rings. The butter¯y con®g-
uration of DDNU is distorted compared with that of DDT
(DeLacy & Kennard, 1972) and its metabolites. The absence
of Cl atoms at the terminal C atom, as well as the presence of
ClÁ Á ÁCl short contacts, might be responsible for this distortion
compared with DDTand its congeners. Therefore, the unit-cell
parameters of DDNU are also different. The unit-cell para-
meters of DDNU, DDMU, DDE and DDT are compared in
Table 1. The CÐC bond distances to the terminal C atom of
DDNU are also different from those in DDT and its related
compounds (Table 2).
Received 22 May 2006
Accepted 3 October 2006
Online 31 October 2006
The title compound, C14H10Cl2, crystallizes as colourless
prisms with two symmetry-independent molecules in the unit
cell. Numerous intermolecular CÐHÁ Á Áꢀ interactions domi-
nate in the crystal structure, where CÐHÁ Á ÁCl and long
ClÁ Á ÁCl contacts are also observed.
Comment
1,1-Bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) has
been recognized as one of the most problematic persistent
organic pollutants (POPs). These compounds are relatively
recent in origin, dating to the boom in industrial production
after World War II. It has been found that DDT causes serious
health and developmental problems in humans and wildlife
even at low concentrations (Fellenberg, 2000). Therefore,
extensive studies have been carried out using several methods
In the crystal structure of DDNU, numerous intermolecular
CÐHÁ Á Áꢀ interactions dominate in the crystal structure and
È
for the degradation of DDT (Alonso et al., 2002; Haggblom &
Bossert, 2003). Recently, the partial electrochemical
dechlorination of DDT mediated by a hydrophobic cobalamin
derivative (hydrophobic vitamin B12) yielded various
dechlorinated products, such as 1,1-bis(4-chlorophenyl)-2,2-
dichloroethane (DDD), 1,1-bis(4-chlorophenyl)-2,2-dichloro-
ethylene (DDE), 1,1,4,4-tetrakis(4-chlorophenyl)-2,3-di-
chloro-2-butene (TTDB) and 1-chloro-2,2-bis(4-chlorophenyl)-
ethylene (DDMU) (Shimakoshi, Tokunaga & Hisaeda, 2004).
Structural data for DDD, DDE and DDMU have been
reported from the viewpoint of toxicity (Shields et al., 1977;
Kennard et al., 1984). We have also reported the crystal
structure and geometry of (E)-TTDB (Shimakoshi, Aritome et
al. 2004) and (Z)-TTDB (Shimakoshi et al., 2005). With
increasing environmental concern, it is imperative that new
environmentally friendly approaches for the dechlorination of
DDT be developed. To achieve this, DDTwas dechlorinated in
an ionic liquid system, 1-butyl-3-methylimidazolium tetra-
¯uoroborate, or [bmim]BF4, and the title compound, 1,10-
(ethenylidene)bis(4-chlorobenzene), DDNU, was obtained as
one of the dechlorinated products. The ionic liquid system was
explained brie¯y by Sheldon (2001) and Welton (1999). In this
Figure 1
The two crystallographically independent molecules of DDNU in the
asymmetric unit, showing the atom-numbering scheme. Displacement
ellipsoids are drawn at the 50% probability level and H atoms are shown
as small spheres of arbitrary radii.
Acta Cryst. (2006). C62, o663±o665
DOI: 10.1107/S0108270106040753
# 2006 International Union of Crystallography o663

organic compounds
slow evaporation of a solution of DDNU in chloroform±ethanol (1:1
v/v) as colourless prisms within 3±4 d.
Crystal data
3
Ê
C14H10Cl2
V = 1209.6 (4) A
Z = 4
Mr = 249.12
Triclinic, P1
a = 9.715 (2) A
3
Dx = 1.368 Mg m
Mo Kꢁ radiation
Ê
Ê
1
b = 9.745 (2) A
ꢄ = 0.50 mm
T = 173 (2) K
Ê
c = 13.868 (2) A
ꢁ = 91.210 (4)ꢀ
ꢂ = 102.457 (3)ꢀ
ꢃ = 108.561 (4)ꢀ
Prism, colourless
0.25 Â 0.10 Â 0.10 mm
Data collection
Bruker SMART APEX CCD area-
detector diffractometer
' and ! scans
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
Tmin = 0.884, Tmax = 0.951
7314 measured re¯ections
4553 independent re¯ections
2835 re¯ections with I > 2ꢅ(I)
Rint = 0.026
ꢆmax = 25.7ꢀ
Figure 2
A view of the partial packing of DDNU, showing CÐHÁ Á Áꢀ, CÐHÁ Á ÁCl
and ClÁ Á ÁCl interactions as dashed lines. Only H atoms involved in these
interactions are shown. [Symmetry codes: (i) x, y + 1, z; (ii) x + 1, y + 1,
z + 2; (iii) x, y + 1, z + 1; (iv) x, y, z + 1.]
Re®nement
Re®nement on F2
R[F2 > 2ꢅ(F2)] = 0.055
wR(F2) = 0.155
S = 1.00
4553 re¯ections
289 parameters
H-atom parameters constrained
w = 1/[ꢅ2(Fo2) + (0.0845P)2]
2
where P = (Fo + 2Fc2)/3
(Á/ꢅ)max = 0.001
3
Ê
Áꢇmax = 0.53 e A
long ClÁ Á ÁCl contacts are also observed. Additionally, there is
3
Ê
0.38 e A
Áꢇmin
=
Ê
a C25ÐH25Á Á ÁCl2(x, y + 1, z) contact of 3.798 (3) A, with the
C25ÐH25Á Á ÁCl2 angle being 151ꢀ. These contacts may be
characterized as weak electrostatic interactions rather than
weak hydrogen bonds (Bats et al., 2001). A partial packing
view of the crystal organization of DDNU showing CÐHÁ Á Áꢀ,
CÐHÁ Á ÁCl and weak ClÁ Á ÁCl short contacts is presented in
Fig. 2, and details of four distinct CÐHÁ Á Áꢀ interactions
between the two independent molecules of DDNU in the
asymmetric unit are given in Table 3.
Ê
H atoms were located in geometric positions (CÐH = 0.94±0.98 A)
and re®ned as riding, with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C).
The residual electron-density map contained small peaks of electron
density (ca 0.53 e A 3) in the vicinity of atom Cl2.
Ê
Data collection: SMART (Bruker, 2001); cell re®nement: SMART;
data reduction: SAINT (Bruker, 2001); program(s) used to solve
structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne
structure: SHELXL97 (Sheldrick, 1997); molecular graphics:
Ê
A Cl1Á Á ÁCl2(x, y, z + 1) interaction of 3.4432 (13) A in the
symmetric units of two DDNU molecules is also observed. The
intermolecular ClÁ Á ÁCl short contact distance is less than the
Table 1
Comparison of unit-cell parameters of DDNU, DDMU, DDE and DDT.
Ê
sum of the van der Waals radii (3.50 A; Bondi, 1964). It has
Parameter
DDNUa
DDMUb
DDEc
DDTd
been reported (Gavezzotti & Filippini, 1993; Rowland &
Taylor, 1996; Cox et al., 1997) in many halogen-containing
crystal structures in the Cambridge Structural Database (CSD,
Version 5.25; Allen, 2002) that a signi®cant number of ClÁ Á ÁCl
Ê
a (A)
9.715 (2)
9.745 (2)
13.868 (2)
91.210 (4)
102.457 (3)
108.561 (4)
1209
15.163 (7)
5.824 (2)
7.452 (3)
9.219 (1)
35.496 (5)
9.438 (1)
9.963 (1)
19.200 (2)
7.887 (1)
Ê
b (A)
Ê
c (A)
ꢁ (ꢀ)
ꢂ (ꢀ)
ꢃ (ꢀ)
Ê
non-bonded contacts of less than 3.5 A have been observed. It
100.12 (3)
114.70 (1)
has been suggested (Pedireddi et al., 1994) that polarization
and anisotropic electron distribution are important factors in
the formation of these short contacts. This may be one of the
reasons for the difference in the CÐC bond length on the
terminal C atom of the ethylene unit between DDE and
DDNU. Successive Cl substituents at the terminal C atom
appear to alter signi®cantly the torsion angles between
DDNU, DDMU and DDE, and these are compared in Table 4.
3
Ê
V (A )
648
P21
3088
P21/c
1509
Pca21
Space group
P1
References: (a) this work; (b) Kennard et al. (1984); (c) Shields et al. (1977); (d) DeLacy
& Kennard (1972).
Table 2
Comparison of selected bond lengths (A) at the terminal C atom between
DDNU, DDMU, DDE and DDT.
Ê
Bond
DDNUa
DDMUb
1.296 (1)
1.483
DDEc
DDTd
Experimental
C1ÐC2
C15ÐC16
C2ÐC3
C16ÐC17
C2ÐC9
C16ÐC23
1.339 (5)
1.342 (4)
1.483 (4)
1.492 (4)
1.477 (4)
1.476 (4)
1.320 (1)
1.322 (1)
1.487 (9)
1.491 (9)
1.492 (1)
1.471 (1)
1.540 (4)
1.531 (4)
1.522 (8)
The title compound, DDNU, was obtained from the electrolysis of
DDT in the ionic liquid system of 1-butyl-3-methylimidazolium
tetra¯uoroborate, or [bmim]BF4, with a carbon felt electrode (CFE)
(area 3 Â 1 cm) containing a catalytic amount of a hydrophobic
vitamin B12 derivative at an applied potential of 1.5 V versus Ag/
AgCl. Single crystals suitable for X-ray analysis were obtained by
1.515 (8)
References: (a) this work; (b) Kennard et al. (1984); (c) Shields et al. (1977); (d) DeLacy
& Kennard (1972).
ꢁ
o664 Jabbar et al. C14H10Cl2
Acta Cryst. (2006). C62, o663±o665

organic compounds
Table 3
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: GZ3023). Services for accessing these data are
described at the back of the journal.
ꢀ
Ê
Geometry of CÐHÁ Á Áꢀ interactions (A, ) for DDNU.
Cg1, Cg2 and Cg3 are the centroids of rings C9±C14, C3±C8 and C23±C28,
respectively.
References
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
Allen, F. H. (2002). Acta Cryst. B58, 380±388.
C27ÐH27Á Á ÁCg1
C24ÐH24Á Á ÁCg1i
C19ÐH19Á Á ÁCg2ii
C13ÐH13Á Á ÁCg3iii
0.95
0.95
0.95
0.95
2.918
2.793
2.897
3.063
3.676
3.599
3.614
3.773
137
143
133
132
Alonso, F., Beletskaya, I. P. & Yus, M. (2002). Chem. Rev. 102, 4009±4091.
Bats, J. W., Frost, T. M. & Hashmi, A. S. K. (2001). Acta Cryst. C57, 1081±1083.
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Bruker (2001). SAINT (Version 6.28a), SMART (Version 5.625) and
SHELXTL (DOS/Windows-NT Version 6.10). Bruker AXS Inc., Madison,
Wisconsin, USA.
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Table 4
Comparison of selected torsion angles (ꢀ) for DDNU, DDMU and DDE.
Angle
DDNUa
DDMUb
DDEc
C1ÐC2ÐC9ÐC14
C1ÐC2ÐC3ÐC8
C15ÐC16ÐC17ÐC22
C15ÐC16ÐC23ÐC28
152.18 (3)
104.0 (1)
38.0 (1)
127.0 (1)
È
Haggblom, M. M. & Bossert, I. D. (2003). Editors. Dehalogenation: Microbial
Processes and Environmental Applications. Boston, Massachusetts: Kluwer
135.39 (4)
148.70 (3)
138.30 (4)
52.0 (1)
121.0 (1)
48.3 (1)
Academic Publishers.
Kennard, C. H. L., Smith, G., Palm, T.-B., Hovmoller, S. & Sjogren, A. (1984).
J. Agric. Food Chem. 32, 886±895.
È
È
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G. R. (1994). J. Chem. Soc. Perkin Trans. 2, pp. 2353±2360.
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Sheldon, R. (2001). Chem. Commun. pp. 2399±2407.
SHELXTL (Bruker, 2001); software used to prepare material for
publication: SHELXTL.
È
Sheldrick, G. M. (1996). SADABS. University of Gottingen, Germany.
Sheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of
GoÈttingen, Germany.
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Trans. 2, pp. 460±463.
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This work was supported by a Grant-in-Aid for Scienti®c
Research on Priority Areas from the Ministry of Education,
Culture, Sports, Science and Technology (MEXT) of Japan, a
Grant-in-Aid for Scienti®c Research from the Japanese
Society for the Promotion of Science (JSPS), and an Industrial
Technology Research Grant Programme in 2005 from the New
Energy and Industrial Technology Development Organization
(NEDO) of Japan.
Shimakoshi, H., Tokunaga, M. & Hisaeda, Y. (2004). Dalton Trans. pp. 878±
882.
Welton, T. (1999). Chem. Rev. 99, 2071±2084.
ꢁ
Acta Cryst. (2006). C62, o663±o665
Jabbar et al. C14H10Cl2 o665