C - H...O, C - H...π and π-π interactions in three benzofuran-2-yl ketone derivatives

Article abstract of DOI:10.1107/S0108270105016185

The molecules of 2-benzoyl-1-benzofuran, C₁₅H₁₀O ₂, (I), interact through double C-H...O hydrogen bonds, forming dimers that are further linked by C-H...O, C-H...π and π-π interactions, resulting in a three-dimensional sup

Full text of DOI:10.1107/S0108270105016185

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
receptor ligands, because selective estrogen receptor modu-
lators such as ralixofene have emerged as potential ther-
apeutics for the prevention and treatment of osteoporosis
(Sato et al., 1999; Smith et al., 2002). Amiodarone is a well
known mitocondrial toxin containing a benzofuran ring.
Amiodarone is used in the treatment and prophylaxis of both
ventricular and superventricular arrhythmias, particularly in
patients with heart insuf®ciency, because this compound has
no signi®cant negative inotropic effect (Spaniol et al., 2001).
Although the synthesis of 2-benzoyl-1-benzofuran, (I), is
known (Demirayak et al., 2002), a literature search showed
that its structure has not yet been characterized. In addition to
(I), we report the molecular and supramolecular structures
of two new furan derivatives, namely bis(5-bromo-1-benzo-
furan-2-yl) ketone, (II), and 3-mesityl-3-methylcyclobutyl
ISSN 0108-2701
CÐHÁ Á ÁO, CÐHÁ Á Áp and p±p inter-
actions in three benzofuran-2-yl
ketone derivatives
a
b
c
Veysel T. Yilmaz, * Canan Kazak, Cumhur Kirilmis,
c
d
Murat Koca and Frank W. Heinemann
a
Department of Chemistry, Faculty of Arts and Sciences, Ondokuz Mayis University,
b
55139 Kurupelit, Samsun, Turkey, Department of Physics, Faculty of Arts and
3
-methylnaphtho[1,2-b]furan-2-yl ketone, (III).
Sciences, Ondokuz Mayis University, 55139 Kurupelit, Samsun, Turkey,
c
Department of Chemistry, Faculty of Arts and Sciences, Firat University,
d
2
3169 Elazig, Turkey, and Institut f uÈ r Anorganische Chemie, Universit aÈ t
Erlangen-N uÈ rnberg, D-91058 Erlangen, Germany
Correspondence e-mail: vtyilmaz@omu.edu.tr
Received 12 May 2005
Accepted 20 May 2005
Online 22 June 2005
The molecules of 2-benzoyl-1-benzofuran, C H O , (I),
1
5
10
2
interact through double CÐHÁ Á ÁO hydrogen bonds, forming
dimers that are further linked by CÐHÁ Á ÁO, CÐHÁ Á Áꢀ and ꢀ±
ꢀ interactions, resulting in a three-dimensional supramole-
cular network. The dihedral angle between the benzoyl and
ꢀ
benzofuran fragments in (I) is 46.15 (3) . The molecules of
bis(5-bromo-1-benzofuran-2-yl) ketone, C H Br O , (II),
1
7
8
2
3
exhibit C symmetry, with the carbonyl group (C O) lying
2
Views of the molecular structures of compounds (I)±(III),
including the atom-numbering schemes, are shown in Figs. 1±3.
Selected bond distances and angles are listed in Tables 1, 3 and
along the twofold rotation axis, and are linked by a
combination of CÐHÁ Á ÁO and CÐHÁ Á Áꢀ interactions and
BrÁ Á ÁBr contacts to form sheets. The stability of the molecular
packing in 3-mesityl-3-methylcyclobutyl 3-methylnaphtho[1,2-
b]furan-2-yl ketone, C H O , (III), arises from CÐHÁ Á Áꢀ
5
. Compounds (I)±(III) consist mainly of a furan-2-yl moiety
connected to another fragment by a carbonyl group. The
O bond distances and the CÐCÐC bond angles between
2
8
28
2
C
and ꢀ±ꢀ stacking interactions. The fused naphthofuran moiety
two fragments are similar in all three compounds. The
carbonyl group is known to coordinate to metal ions rather
easily, and the presence of the furan O atom adjacent to the
carbonyl group in (I)±(III) makes these compounds potential
bidentate chelating agents, as reported for lanthanum (Benassi
et al. 1987). In (I), the fused benzofuran ring is essentially
in (III) is essentially planar and makes a dihedral angle of
ꢀ
8
1.61 (3) with the mean plane of the trimethylbenzene ring.
Comment
Conventional `strong and directional' hydrogen bonds, such as
OÐHÁ Á ÁO, NÐHÁ Á ÁO and OÐHÁ Á ÁN, have long been
recognized as being of fundamental importance in deter-
mining the supramolecular structure of organic solids
(
Desiraju & Steiner, 1999). In molecules lacking these
hydrogen-bond donors and acceptors, other types of weak and
less directional forces, such as CÐHÁ Á ÁO, CÐHÁ Á Áꢀ and ꢀ±ꢀ
interactions, become important in generating supramolecular
architectures (Desiraju & Steiner, 1999; Hunder & Sanders,
1
2
990; Nishio et al., 1998; Umezawa et al., 1998; Calhorda,
000). Since many natural benzofurans have physiological,
pharmacological and toxic properties, there is continuing
interest in their synthesis (Kappe et al., 1997). Various
benzofuran derivatives have been investigated as estrogen
Figure 1
The molecular structure of (I), showing the atom-labeling scheme (50%
probability displacement ellipsoids).
o438 # 2005 International Union of Crystallography
DOI: 10.1107/S0108270105016185
Acta Cryst. (2005). C61, o438±o441

organic compounds
ꢀ
planar and makes a dihedral angle of 46.15 (3) with the
two hydrogen bonds and donates two hydrogen bonds, thus
forming chains running parallel to the crystallographic b axis.
These chains are further linked by relatively short BrÁ Á ÁBr
planar benzoyl ring. The conformation of compound (I) is
similar to those of previously reported benzoylbenzofuran
derivatives (Benassi et al., 1987; Pei et al., 2005). The crystal
packing of (I) is governed by a set of weak intermolecular
ix
1
2
Ê
contacts [BrÁ Á ÁBr = 3.499 (2) A; symmetry code: (ix) � x,
5
2
� y, � z], resulting in a two-dimensional layer architecture
i
Ê
interactions. A dimer is formed via a C2ÐH2AÁ Á ÁO1
(Fig. 5). The CÐBrÁ Á ÁBr angle is 146.85 (12) A, and the
hydrogen bond (see Table 2 for geometry and symmetry
code), and the dimeric units are held together by a C7Ð
BrÁ Á ÁBr interactions play a crucial role in determining the
crystal packing and compete successfully with other kinds of
weak intermolecular interactions.
ii
H7AÁ Á ÁO2 hydrogen bond (Table 2), two CÐHÁ Á Áꢀ inter-
iii
iv
Ê
actions [C5ÐH5AÁ Á ÁCg2 = 3.28 A and C15ÐH15AÁ Á ÁCg1 =
Compound (III) consists of a fused naphthofuran moiety
(O2/C16±C27), a cyclobutane ring (C7/C9±C11) and a mesityl
group (C1±C6/C12±C14). The naphthofuran and mesityl ring
systems are essentially planar, and the dihedral angle between
Ê
.80 A, where Cg1 and Cg2 are the centroids of the C1±C6 and
2
C10±C15 benzene rings; symmetry codes: (iii) � x, 1 � y, � z;
v
(
3
iv) 1 � x, 1 � y, � z] and two ꢀ±ꢀ interactions [Cg1Á Á ÁCg1 =
vi
ꢀ
Ê
Ê
.561 (1) A and Cg2Á Á ÁCg2 = 3.776 (1) A; symmetry codes:
their planes is 81.86 (3) , differing from the values reported
ꢀ
(
dimensional supramolecular network (Fig. 4).
v) � x, � y, � z; (vi) 1 � x, 1 � y, 1 � z], resulting in a three-
for 1-(1-benzofuran-2-yl)-2-mesitylethanone [89.08 (4) ; Arõcõ
et al., 2004] and (benzofuran-2-yl)(3-methyl-3-phenylcyclo-
ꢀ
The molecules of (II) contain two symmetry-related planar
bromobenzofuran rings attached to the carbonyl group
(C9 O2), which is situated on the twofold rotation axis. The
dihedral angle between the planes of the two equivalent
butyl)methanone [73.63 (6) ; Y uÈ ksektepe et al., 2004]. These
differences may be explained by the presence of the different
substituents in these compounds. The cyclobutane ring devi-
ates signi®cantly from planarity, with a puckering parameter
ꢀ
Ê
bromobenzofuran ring moieties is 32.70 (4) . In the packing of
(
(q ) of 0.3972 (4) A, and this ®nding is consistent with a similar
2
II), the molecules are linked by a combination of a CÐHÁ Á ÁO
viii
benzofuran derivative containing
(Y uÈ ksektepe et al., 2004). However, a nearly planar cyclo-
a
cyclobutane ring
hydrogen bond (Table 4) and a CÐHÁ Á Áꢀ interaction [C2Ð
Ê
È
butane ring was also reported by Ozdemir et al. (2004). The
H2AÁ Á ÁCg = 2.87 A; Cg is the centroid of the C1±C6 ring;
1
2
symmetry code: (viii) x, 1 � y, � + z]. Each molecule accepts
dihedral angles between the planes of the naphthofuran/
cyclobutane and mesityl/cyclobutane ring systems are
ꢀ
5
2.15 (5) and 38.26 (8) , respectively. In contrast to
compounds (I) and (II), compound (III) does not exhibit CÐ
HÁ Á ÁO hydrogen bonds, and molecules of (III) are held
together by CÐHÁ Á Áꢀ and ꢀ±ꢀ interactions (Fig. 6). There are
three CÐHÁ Á Áꢀ interactions between the H atoms of the
Figure 2
The molecular structure of (II), showing the atom-labeling scheme (50%
probability displacement ellipsoids). [Symmetry code: (viii) 1 � x, y,
1
2
�
z.]
Figure 4
A packing diagram of (I). CÐHÁ Á ÁO interactions are indicated by double
dashed lines and CÐHÁ Á Áꢀ interactions by single dashed lines, while ꢀ±ꢀ
interactions are shown as double thin lines. O atoms are shown with
octant shading.
Figure 3
The molecular structure of (III), showing the atom-labeling scheme (50%
probability displacement ellipsoids).
ꢁ
Acta Cryst. (2005). C61, o438±o441
Yilmaz et al.
15 10
C H O
, C17H Br
2 8 2
O
3
and C28H
28
O
2
o439

organic compounds
(
20.70 g, 0.15 mol) was stirred in dry acetone (250 ml) at room
temperature for 2 h. A solution of 1,3-dichloroacetone (6.35 g,
.05 mol) in dry acetone (20 ml) was added and this mixture was
0
poured into water (250 ml). The separated solid was ®ltered off,
washed with water and recrystallized from tetrahydrofuran to give
(
II) (yield 33.8 g, 80.5%). For the preparation of (III), hydroxy-
naphthophenone (1.86 g, 10 mmol), potassium carbonate (2.07 g,
5 mmol) and dry tetrahydrofuran (100 ml) were placed in a 500 ml
1
two-necked ¯ask ®tted with a re¯ux condenser, and the mixture was
stirred for 1 h at room temperature. To this solution, a solution
of 3-(2-chloro-1-oxoethyl)-1-mesityl-1-methylcyclobutane (2.64 g,
10 mmol) in acetonitrile (100 ml) was added dropwise over a period
of about 30 min and the mixture was subsequently re¯uxed for 4 h.
The progress of the reaction was monitored by IR spectroscopy. The
mixture was allowed to cool to room temperature, and was then
poured into water (500 ml) and reprecipitated twice from water. The
solid was ®ltered off and recrystallized from tetrahydrofuran to
obtain crystals of (III) (yield 2.85 g, 71.96%).
Compound (I)
Figure 5
Crystal data
A packing diagram of (II). CÐHÁ Á ÁO interactions are represented as
double dashed lines and BrÁ Á ÁBr contacts are indicated by single dashed
lines. O atoms are shown with octant shading.
C
15
H O
10 2
Z = 2
= 1.402 Mg m
Mo Kꢁ radiation
�
3
M
r
= 222.23
Triclinic, P1
D
x
Ê
a = 6.1028 (5) A
Cell parameters from 36
re¯ections
Ê
b = 8.8010 (4) A
Ê
c = 10.1195 (6) A
ꢀ
ꢄ = 6.0±20.0
ꢀ
ꢀ
� 1
ꢁ
= 97.700 (4)
ꢅ = 0.09 mm
T = 100 (2) K
ꢂ = 93.710 (6)
ꢀ
ꢃ = 101.073 (6)
V = 526.31 (6) A
Prism, colorless
0.34 Â 0.31 Â 0.28 mm
Ê
3
Data collection
Bruker±Nonius KappaCCD
diffractometer
Rint = 0.070
ꢀ
ꢄ
max = 27.9
'
and ! scans
h = � 8 ! 8
1
2
2
7534 measured re¯ections
498 independent re¯ections
049 re¯ections with I > 2ꢆ(I)
k = � 11 ! 11
l = � 13 ! 13
Figure 6
A packing diagram of (III), viewed along the crystallographic b axis. CÐ
HÁ Á Áꢀ interactions are indicated by double dashed lines, while ꢀ±ꢀ
interactions are shown as double thin lines. O atoms are shown with
octant shading.
Re®nement
2
2
2
2
Re®nement on F
2
w = 1/[ꢆ (F ) + (0.0496P)
o
2
R[F > 2ꢆ(F )] = 0.040
wR(F ) = 0.098
+ 0.1374P]
where P = (Fo + 2F )/3
2
2
2
c
x
methyl groups and the benzene rings [C13ÐH13AÁ Á ÁCg1 =
S = 1.06
2498 re¯ections
154 parameters
H-atom parameters constrained
(Á/ꢆ)max = 0.001
Áꢇmax = 0.23 e AÊ
�
3
xi
Ê
iii
Ê
3
Cg2 = 2.87 A, where Cg1 and Cg2 are the centroids of the
.20 A, C14ÐH14BÁ Á ÁCg1 = 2.73 A and C28ÐH28AÁ Á Á
Áꢇmin = � 0.30 e AÊ
� 3
Ê
C1±C6 and C21±C26 rings, respectively; symmetry codes: (x)
1
1
2
1
2
1
2
�
x, + y, � z; (xi) 1 � x, � + y, � z]. In (III), the packing of
2
Table 1
Selected geometric parameters (A, ) for (I).
the molecules is additionally reinforced by a ꢀ±ꢀ stacking
interaction between adjacent naphthalene rings, with a
Cg1Á Á ÁCg1 distance of 3.695 (1) A.
Ê
ꢀ
iii
Ê
O2ÐC9
C8ÐC9
1.2257 (14)
1.4678 (17)
C9ÐC10
1.4932 (16)
C8ÐC9ÐC10
118.74 (10)
Experimental
For the preparation of (I), a mixture of salicylaldehyde (12.21 g,
0.1 mol) and potassium carbonate (20.70 g, 0.15 mol) was stirred in
dry acetone (250 ml) at room temperature for 2 h. A solution of
phenacyl bromide (19.90 g, 0.1 mol) in dry acetone (20 ml) was added
to this mixture. The resulting solution was poured into water (250 ml)
and reprecipitated twice from water. Suitable crystals of (I) were
obtained by recrystallizing the precipitate from acetone (yield
Table 2
Hydrogen-bond geometry (A, ) for (I).
Ê
ꢀ
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
i
C2ÐH2AÁ Á ÁO1
0.95
0.95
2.57
2.55
3.4182 (14)
3.1449 (14)
149
121
ii
C7ÐH7AÁ Á ÁO2
19.60 g, 89.1%). For the preparation of (II), a mixture of 5-bromo-2-
hydroxybenzaldehyde (20.10 g, 0.1 mol) and potassium carbonate
Symmetry codes: (i) � x ‡ 1; � y; � z; (ii) x � 1; y; z.
Acta Cryst. (2005). C61, o438±o441
ꢁ
o440 Yilmaz et al.
15 10 2 8 2 3 28 2
C H O , C17H Br O and C28H O

organic compounds
Compound (II)
Re®nement
2
2
2
2
Re®nement on F
2
w = 1/[ꢆ (F ) + (0.0429P)
o
Crystal data
2
R[F > 2ꢆ(F )] = 0.044
wR(F ) = 0.106
+ 1.2434P]
�
3
2
2
o
2
C
17
8
H Br
O
2 3
D
x
= 1.994 Mg m
where P = (F
(Á/ꢆ)max = 0.004
+ 2F )/3
c
M
r
= 420.05
Mo Kꢁ radiation
S = 1.03
4182 re¯ections
Ê
Áꢇmax = 0.26 e A
� 3
Monoclinic, C2=c
Cell parameters from 89
re¯ections
Áꢇmin = � 0.25 e AÊ �
3
Ê
a = 29.644 (2) A
276 parameters
H-atom parameters constrained
Ê
ꢀ
b = 6.2536 (5) A
ꢄ = 6.0±20.0
ꢅ = 5.80 mm
T = 100 (2) K
Ê
� 1
c = 7.8188 (8) A
ꢀ
Ê
ꢂ = 105.091 (6)
V = 1399.5 (2) A
Z = 4
3
Table 5
Selected interatomic distances (A) for (III).
Irregular, colorless
0.25 Â 0.24 Â 0.16 mm
Ê
Data collection
O1ÐC15
C11ÐC15
1.2237 (19)
1.505 (2)
C15ÐC16
1.473 (2)
Bruker±Nonius KappaCCD
diffractometer
1814 independent re¯ections
1604 re¯ections with I > 2ꢆ(I)
'
and ! scans
Absorption correction: multi-scan
SADABS; Bruker, 2002)
min = 0.262, Tmax = 0.398
9777 measured re¯ections
Rint = 0.046
ꢀ
ꢄ
max = 28.7
All H atoms were re®ned using a riding model, with CÐH
Ê
distances of 0.95±1.00 A and Uiso(H) values of 1.2Ueq(C).
(
T
h = � 40 ! 40
k = � 8 ! 8
For all compounds, data collection: COLLECT (Bruker, 2002);
cell re®nement: EVALCCD (Duisenberg et al., 2003); data reduction:
EVALCCD; program(s) used to solve structure: SHELXTL (Bruker,
2002); program(s) used to re®ne structure: SHELXTL; molecular
graphics: SHELXTL; software used to prepare material for publi-
cation: SHELXTL.
1
l = � 10 ! 10
Re®nement
2
2
2
2
Re®nement on F
2
w = 1/[ꢆ (F ) + (0.0084P)
o
2
R[F > 2ꢆ(F )] = 0.019
wR(F ) = 0.043
S = 1.08
+ 2.8382P]
where P = (Fo + 2F )/3
2
2
2
c
(Á/ꢆ)max = 0.001
Ê
� 3
Áꢇmax = 0.43 e A
1
1
814 re¯ections
01 parameters
Áꢇmin = � 0.32 e AÊ
� 3
The authors thank Ondokuz Mayis and Firat Universities
for the ®nancial support given to the study.
H-atom parameters constrained
Table 3
Selected geometric parameters (A, ) for (II).
Ê
ꢀ
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SQ1211). Services for accessing these data are
described at the back of the journal.
Br1ÐC4
O2ÐC9
1.9010 (16)
1.223 (3)
C8ÐC9
1.473 (2)
118.4 (2)
vii
C8 ÐC9ÐC8
O2ÐC9ÐC8
120.81 (10)
References
1
2
Symmetry code: (vii) � x ‡ 1; y; � z ‡ .
È
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Ê
ꢀ
6.12). Bruker AXS Inc., Madison, Wisconsin, USA.
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HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
xii
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2.56
3.429 (2)
151
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�
3
C
28
28
H O
2
D
x
= 1.250 Mg m
14233.
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r
= 396.50
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a = 7.3816 (3) A
b = 8.2874 (6) A
Ê
c = 34.591 (2) A
ꢂ = 95.487 (5)
V = 2106.4 (2) A
Z = 4
Cell parameters from 134
re¯ections
1
Ê
Ê
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ꢄ = 6.0±20.0
ꢅ = 0.08 mm
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� 1
ꢀ
Ê
3
Block, colorless
0.34 Â 0.25 Â 0.16 mm
Data collection
Bruker±Nonius KappaCCD
diffractometer
4182 independent re¯ections
3360 re¯ections with I > 2ꢆ(I)
'
and ! scans
Absorption correction: multi-scan
SADABS; Bruker, 2002)
min = 0.970, Tmax = 0.988
0365 measured re¯ections
Rint = 0.032
ꢀ
ꢄ
max = 26.4
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Chem. Soc. Jpn, 71, 1207±1213.
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Acta Cryst. C60, o509±o510.
(
T
h = � 9 ! 9
k = � 10 ! 10
l = � 43 ! 43
2
ꢁ
Acta Cryst. (2005). C61, o438±o441
Yilmaz et al.
15 10
C H O
, C17H Br
2 8 2
O
3
and C28H
28
O
2
o441