organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
the molecular packing in the crystal of (I) and a brief study of
the CÐHÁ Á ÁO hydrogen bonds in (I) and some similar crystals.
ISSN 0108-2701
1
-(4-Bromophenyl)-3-(4-methyl-
1
phenyl)prop-2-en-1-one
Lei Wang, Yong Zhang, Cheng-Rong Lu and De-Chun
Zhang*
Department of Chemistry, Suzhou University, Suzhou 215006, People's Republic of
China
The molecule of (I) (Fig. 1) is not planar. Taking the C1±C6
benzene ring as plane 1 (P1), the C7±C12 benzene ring as
plane 2 (P2) and the central C1ÐC13 C14ÐC15 as plane 3
Received 2 April 2004
Accepted 21 July 2004
Online 21 August 2004
(
P3), the dihedral angles between them, A , A and A , are
12 13 23
In the molecule of the title compound, C H BrO, the two
1
ꢀ
6
13
47.0 (1), 11.7 (0) and 35.4 (1) , respectively, showing that the
two benzene rings are rotated in opposite directions with
respect to the central part, plane 3. The C1ÐC13 C14ÐC15
torsion angle is 175.1 (3) . The angle between the C O bond
and plane 3 is 14.2 (3) . Further geometric parameters are
given in Table 1.
benzene rings are rotated in opposite directions with respect
to the central CÐC CÐC part of the molecule. The phenone
O atom deviates from the least-squares plane of the molecule
ꢀ
ꢀ
Ê
by 0.300 (3) A. In the crystal structure, molecules are paired
through CÐHÁ Á Áꢀ interactions. The molecular pairs along
[001] are hydrogen bonded through three translation-related
In the crystal structure of (I), molecules are paired through
CÐHÁ Á Áꢀ interactions (Suezawa et al., 2001) (Table 3). The
shortest distance between parallel C C double bonds is
co-operative hydrogen bonds in the `bay area', forming
molecular chains, which are further hydrogen bonded through
CÐHÁ Á ÁBr weak interactions, forming (010) molecular layers.
In the third direction, there are only weak van der Waals
interactions. The co-operative hydrogen bonds in the `bay
area' are discussed brie¯y.
Ê Ê
4
photoreactive crystal (Turowska-Tyrk et al., 2003). The dihe-
.557 (4) A, much longer than the 4.2 A reference value for a
dral angle between plane 3 and the plane formed by the two
ꢀ
C
C double bonds is 45.6 (3) , which deviates signi®cantly
ꢀ
from the perfect value of 90 for 2+2 photocycloaddition. This
is consistent with the fact that the crystal of (I) is photoinert.
The packing in (I) is illustrated in Fig. 2. The molecules
along [001] interact via three CÐHÁ Á ÁO interactions
Comment
Chalcones with the general formula Ar±CH CH±CO±Ar
belong to an important class of compounds. The common and
interesting part in the molecules of these compounds is the
central part, i.e. ÐCH CHÐC OÐ, in which the H atoms
may or may not be substituted. The C C double bond can be
photoreactive, in which case it can react with suitable reagents
through photocycloaddition to synthesize various products,
and it is therefore widely used in organic solid photochemistry
(
Desiraju, 1991), namely C12ÐH12Á Á ÁO1, C2ÐH2Á Á ÁO1 and
C14ÐH14Á Á ÁO1 (Table 2), and form hydrogen-bonded mole-
cular chains. These chains interact further through C5Ð
H5Á Á ÁBr1 and C16ÐH16AÁ Á ÁBr1 hydrogen bonds (Table 2),
forming (010) molecular layers. In the third direction, [010],
there are only weak ordinary van der Waals interactions.
The most interesting features in the structure of (I) are the
above-mentioned co-operative hydrogen bonds, formed by
the phenone O atom and the three CÐH bonds in the `bay
(
Satish Goud et al., 1995).
On the other hand, with appropriate substitutents, chal-
cones are a class of non-linear optical materials (Indira et al.,
002). In these materials, the C O bond acts as the electron-
2
withdrawing group, and electron-rich substituents in the
aromatic rings serve as electron-donating groups, forming a
so-called DÐꢀÁ Á ÁA-type molecule. When the electron-rich
0
groups are located on the 4 and/or 4 positions, the electron
¯ow follows a Ã-shaped path, and therefore the molecule is
called a Ã-shaped molecule (Devia et al., 1999). During our
search for chalcone non-linear optical materials, the title
compound, (I), was synthesized. We present here a study of
Figure 1
A view of the molecular structure of (I), showing the atom-numbering
scheme. Displacement ellipsoids are drawn at the 30% probability level
and H atoms are shown as small spheres of arbitrary radii.
1
Supported by the Key Subject Programme of Jiangsu Province (grant No.
S1109001).
o696 # 2004 International Union of Crystallography
DOI: 10.1107/S0108270104017883
Acta Cryst. (2004). C60, o696±o698