2′-hydroxy-4″-dimethylamino-chalcone

Article abstract of DOI:10.1107/S0108270102010247

The title compound, 3-[4-(dimethylamino)phenyl]-1-(2-hydroxyphenyl)prop-2-en-1-one, C₁₇H₁₇NO₂, is a chalcone derivative substituted by 2′-hydroxyl and 4″-dimethylamino groups. The crystal structure indicates that the anili

Full text of DOI:10.1107/S0108270102010247

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
between the phenyl rings of the aniline and benzoyl groups is
ꢀ
only 10.32 (16) . There is some noticeable conjugation in the
C10ÐC9 C8ÐC7 bridge between the two phenyl rings, as
ISSN 0108-2701
seen in the increased length of the C8 C9 double bond
Ê
[
[
1.344 (4) A] and the decreased length of the C7ÐC8
Ê
1.447 (4) A] and C9ÐC10 [1.431 (4) A] single bonds.
Ê
0
00
2
-Hydroxy-4 -dimethylamino-
chalcone
Zhiqiang Liu, Qi Fang,* Wentao Yu, Gang Xue, Duxia Cao
and Minhua Jiang
State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100,
Shandong, People's Republic of China
Comparing our results with those of Murafuji et al. (1999), it
can be seen that the planarity of the substituted chalcone
Correspondence e-mail: fangqi@icm.sdu.edu.cn
molecule is strongly affected by the substituted group on the
0
Received 15 May 2002
Accepted 10 June 2002
Online 12 July 2002
2
-position. The hydroxyl group is connected to the carbonyl
by an O1ÐHÁ Á ÁO2 hydrogen bond (Table 1). This HÁ Á ÁO
intramolecular interaction is obviously weaker than the O!B
coordination bond reported by Murafuji et al. (1999).
It is interesting to compare the origination of the dihedral
The title compound, 3-[4-(dimethylamino)phenyl]-1-(2-hy-
droxyphenyl)prop-2-en-1-one, C H NO , is a chalcone
derivative substituted by 2 -hydroxyl and 4 -dimethylamino
groups. The crystal structure indicates that the aniline and
hydroxyphenyl groups are nearly coplanar, with a dihedral
1
7
17
2
ꢀ
ꢀ
0
00
angles of DMAC [18.5 (2) ] and (I) [10.32 (16) ]. In DMAC
with the same atom-numbering scheme as in Fig. 1), the C5Ð
(
ꢀ
ꢀ
C4ÐC7ÐC8 [20.3 (5) ] and C3ÐC4ÐC7ÐO [19.0 (5) ]
torsion angles are remarkable, and make the twist between the
carbonyl plane (C8ÐC7ÐO2) and the phenyl plane (C1±C6)
the main contribution to the non-planarity of DMAC. In (I),
however, the carbonyl plane (C8ÐC7ÐO2) and the phenyl
plane (C1±C6) are nearly coplanar. Obviously, the torsion to
ꢀ
angle of 10.32 (16) between their phenyl rings. The molecular
planarity of this substituted chalcone is strongly affected by
0
the 2 -hydroxyl group.
Comment
In the past decade, synthetic chemosensors have been the
focus of research related to molecular opto-electronics. As
a typical intramolecular charge-transfer (ICT) compound,
0
0
4
-dimethylaminochalcone (DMAC) has been reported to be
a potential chemosensor due to its intense emission (DiCasare
Lakowicz, 2000). In particular, when it is substituted by
different groups and/or is in different micro-surroundings, the
uorescent properties of the molecule can be signi®cantly
&
¯
altered, due to the different ICT nature of the excited states.
To understand this structure±property relationship, some
interesting work has been carried out. Murafuji et al. (1999)
have reported two crystal structures of similar compounds
Figure 1
A view of the molecule of (I). Displacement ellipsoids are drawn at the
30% probability level and H atoms are shown as small spheres of
arbitrary radii.
0
0
with different groups at the 2 -position, namely 2 -diethyl-
0
0
boryl-4 -dimethylaminochalcone and DMAC. In the former
structure, the dihedral angle between the phenyl rings is
ꢀ
3
.28 (9) , but in the latter, which has no substituted group, the
ꢀ
make the carbonyl plane parallel to the phenol plane is the
O1ÐHÁ Á ÁO2 intramolecular interaction. This seems to mean
dihedral angle is 18.5 (2) . The difference comes from an extra
intramolecular BÐO coordination bond. In this paper, we
report the structure of the title compound, (I), which is
-hydroxy-DMAC.
The molecule of (I), along with the atom-numbering
0
that the bonding between the substituted group at the 2 -
position and the O atom of the carbonyl is helpful for
enhancing the planarity of the whole molecule. The stronger
the bonding, the better the planarity. From this point of view,
0
2
0
scheme, is illustrated in Fig. 1. This molecule can be classi®ed
into the D±ꢀ±A (electron donor±ꢀ-bridge±electron acceptor)
model. The dimethylamino, the benzoyl and the styrene
groups act as the electron donor, the electron acceptor and the
ꢀ bridge, respectively. As expected, the backbone of the
compound is nearly planar (Fig. 2). The dihedral angle
we can understand why the planarity of 2 -hydroxy-DMAC,
0
(I), is better than DMAC but poorer than 2 -diethylboryl-
DMAC. The dihedral angle between the two phenyl rings in
(I) comes from a gradual small skewing of the carbon chain
between the two phenyl rings, and the C7ÐC8 C9ÐC10
ꢀ
torsion angle of 3.9 (3) is the largest in this skewing series.
Acta Cryst. (2002). C58, o445±o446
DOI: 10.1107/S0108270102010247
# 2002 International Union of Crystallography o445

organic compounds
As shown in Fig. 2, the molecular planes of all the molecules
are either perpendicular or parallel to each other in the
crystal. Each pair of two nearest molecules is coupled in a
head-to-tail manner. Thus, the main intermolecular interac-
tion can be supposed to be dipole±dipole interactions. From a
check of the intermolecular atomic distances, there are no
other obvious short intermolecular contacts in the crystal.
Concerning the structure±property relationship, we have
Crystal data
�
3
C H NO
1
7
17
2
D = 1.266 Mg m
x
M
r
= 267.32
Mo Kꢂradiation
Monoclinic, P2 =c
Cell parameters from 40
re¯ections
1
Ê
a = 12.1194 (14) A
b = 10.2869 (8) AÊ
ꢀ
ꢃ= 5.1±12.8
Ê
c = 12.5048 (16) A
� 1
ꢄ= 0.08 mm
T = 293 (2) K
ꢀ
Ê
ꢁ
= 115.864 (8)
3
V = 1402.8 (3) A
Z = 4
Prism, red
0.36 Â 0.30 Â 0.20 mm
measured the ¯uorescent properties of both DMAC and
0
Data collection
2
-hydroxy-DMAC, (I), using an Edinburgh FLS920 spectro-
Bruker P4 diffractometer
R
int = 0.028
meter. Both compounds have the same peak position in their
emission spectra, but the ¯uorescent intensity and quantum
ꢀ
!
scans
Absorption correction: scan
XSCANS; Siemens, 1996)
min = 0.807, Tmax = 0.984
ꢃmax = 26
h = � 14 ! 1
(
T
k = � 1 ! 12
l = � 14 ! 15
3
2
1
510 measured re¯ections
745 independent re¯ections
353 re¯ections with I > 2ꢅ(I)
3 standard re¯ections
every 97 re¯ections
intensity decay: none
Re®nement
2
2
2
o
2
Re®nement on F
2
w = 1/[ꢅ(F
where P = (F
(Á/ꢅ)max < 0.001
) + (0.1111P) ]
2
2 2
R[F > 2ꢅ(F )] = 0.065
wR(F ) = 0.216
S = 1.01
o c
+ 2F )/3
2
Ê
� 3
Áꢆmax = 0.32 e A
Ê
� 3
2
1
745 re¯ections
82 parameters
Áꢆmin = � 0.22 e A
Extinction correction: SHELXL97
Extinction coef®cient: 0.012 (4)
H-atom parameters constrained
Table 1
Hydrogen-bonding geometry (A, ).
Ê
ꢀ
Figure 2
A packing diagram for (I).
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
O1ÐH1AÁ Á ÁO2
0.82
1.77
2.504 (3)
147
yield of the former are about 100 times higher than that of the
latter in four kinds of solvent with different polarity, from
toluene to MeCN. We think that the O1ÐHÁ Á ÁO2 hydrogen
bond has both a positive and a negative in¯uence on the
emission properties. The planarity and invariability of a ꢀ-
conjugated organic molecule are important for ¯uorescence.
The intramolecular hydrogen bond in (I) is helpful for
enhancing the molecular planarity, but is not useful for
enhancing the molecular invariability (this hydrogen bond
may induce some structural variability by potentially inducing
more resonance structures). The combined effect is the
enhanced non-radiative energy transfer of (I) and therefore
the enhanced ¯uorescence quenching.
After checking their presence in the difference map, all H atoms
were ®xed geometrically and allowed to ride on their attached atoms,
Ê
with CÐH = 0.93±0.96 A and OÐH = 0.82 A, and Uiso(H) =
Ê
1.2Ueq(C) or 1.5Ueq(O).
Data collection: XSCANS (Siemens, 1996); cell re®nement:
XSCANS; data reduction: XSCANS; program(s) used to solve
structure: SHELXTL (Bruker, 1997); program(s) used to re®ne
structure: SHELXTL; molecular graphics: PLATON (Spek, 2001).
This work was supported by the National Science Founda-
tion of China (grant No. 20172034) and by a grant from the
State Key Programme of China.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: OB1067). Services for accessing these data are
described at the back of the journal.
Experimental
0
A mixture of 2 -hydroxyacetophenone (2.72 g) and boron tri¯uoride
3 2
etherate (2.6 ml, 48% BF ) was heated to re¯ux for 1 h under an N
atmosphere. 4-Dimethylaminobenzaldehyde (3.0 g) in acetic anhy-
dride (10 ml) was then added dropwise. The temperature was kept at
References
Bruker (1997). SHELXTL. Version 5.10. Bruker AXS Inc., Madison,
Wisconsin, USA.
DiCasare, N. & Lakowicz, J. R. (2000). Tetrahedron Lett. 43, 2615±2618.
Murafuji, T., Sugihara, Y., Moriya, T., Mikata, Y. & Yano, S. (1999). New J.
Chem. 23, 683±685.
Sheldrick, G. M. (1997). SHELXL97. University of G oÈ ttingen, Germany.
Siemens (1996). XSCANS. Version 2.2. Siemens Analytical X-ray Instruments
Inc., Madison, Wisconsin, USA.
363 K for a further 2 h. The mixture was then added dropwise to
water and extracted with CH Cl . The organic layer was separated
2
2
out and further puri®ed by column chromatography using petroleum
ether±chloroform (1:1) as eluant. After removal of the solvent under
reduced pressure, dark-red microcrystals of (I) were obtained (yield
78%, 4.15 g; m.p. 449±450 K). A sample of (I) for structure deter-
mination was obtained by recrystallization from acetonitrile.
Spek, A. L. (2001). PLATON. University of Utrecht, The Netherlands.
ꢁ
o446 Zhiqiang Liu et al.
C
17
H
17NO
2
Acta Cryst. (2002). C58, o445±o446