Synthesis, characterization, and crystal structures of 3-bromo-n′-(2- methoxybenzylidene)benzohydrazide and n′-(2-methoxybenzylidene)-3,4- methylenedioxybenzohydrazide

Article abstract of DOI:10.1007/s10870-011-9982-0

Two new hydrazone compounds, 3-bromo-N′-(2-methoxybenzylidene) benzohydrazide (1) and N′-(2-methoxybenzylidene)-3,4- methylenedioxybenzohydrazide (2), have been synthesized and characterized by elemental analysis, IR, and single crystal X-ray diffractions

Full text of DOI:10.1007/s10870-011-9982-0

J Chem Crystallogr (2011) 41:1785–1789
DOI 10.1007/s10870-011-9982-0
ORIGINAL PAPER
Synthesis, Characterization, and Crystal Structures
of 3-bromo-N0-(2-methoxybenzylidene)benzohydrazide and
N0-(2-methoxybenzylidene)-3,4-methylenedioxybenzohydrazide
Hai-Yun Zhu
Received: 28 June 2010 / Accepted: 3 January 2011 / Published online: 9 January 2011
Ó Springer Science+Business Media, LLC 2011
Abstract Two new hydrazone compounds, 3-bromo-
N0-(2-methoxybenzylidene)benzohydrazide (1) and N0-(2-
methoxybenzylidene)-3,4-methylenedioxybenzohydrazide
(2), have been synthesized and characterized by elemental
analysis, IR, and single crystal X-ray diffractions. Com-
pound (1) crystallizes in the triclinic space group P1 with
antiplatelet, antitubercular, anticancer and antitumor act-
ivities [1–4]. Hydrazones possessing an azomethine
–NHN=CH– group constitute an important class of com-
pounds for new drug development. Many researchers have
therefore synthesized these compounds as target structures
and evaluated their biological activities [5–8]. In this paper,
the author reports the syntheses, characterization, and crystal
structures of two new hydrazone compounds 3-bromo-
N0-(2-methoxybenzylidene)benzohydrazide (1) and N0-(2-
methoxybenzylidene)-3,4-methylenedioxybenzohydrazide
(2) (Scheme 1).
˚
unit cell dimensions a = 8.4088(5) A, b = 8.5398(5) A,
˚
˚
c = 10.6572(6) A, a = 90.356(3)°, b = 102.868(3)°, c =
´
3
˚
97.987(3)°, V = 738.28(7) A , Z = 2, R1 = 0.0406, and
wR2 = 0.0804. Compound (2) crystallizes in the tetragonal
space group P41 with unit cell dimensions a = b =
´
3
˚
˚
˚
9.792(4) A, c = 15.788(6) A, V = 1513.8(10) A , Z = 4,
R1 = 0.0415, and wR2 = 0.0818. The molecules of both
compounds display E configurations with respect to the
C=N double bonds. In the crystal structure of (1), mole-
cules are linked through N–HꢀꢀꢀO hydrogen bonds, forming
chains running along the b axis. In the crystal structure of
(2), molecules are linked through N–HꢀꢀꢀO hydrogen
bonds, forming chains running along the c axis.
Experimental
All chemicals with AR grade were commercially available
and used without further purification. C, H, and N ele-
mental analyses were performed on a Perkin-Elmer 240C
elemental analyzer. The IR spectra were measured with a
FT-IR 170-SX (Nicolet) spectrophotometer using KBr
Keywords Hydrazone ꢀ Synthesis ꢀ Hydrogen bonds ꢀ
discs in the range 4000–400 cm-1
.
X-ray crystallography
Synthesis of 3-Bromo-N0-(2-
methoxybenzylidene)benzohydrazide (1)
Introduction
2-Methoxybenzaldehyde (135 mg, 1.0 mmol) and 3-bro-
mobenzohydrazide (215 mg, 1.0 mmol) were mixed and
stirred in methanol (100 mL) for 1 h at ambient tempera-
ture to give a colourless solution. The solution was left to
slow evaporation of the methanol for a week, yielding
colourless block-shaped single crystals. The crystals were
filtered out and washed with methanol. Yiled: 261 mg
(78%). Anal. Calcd. (%) for C15H13BrN2O2: C, 54.1; H,
3.9; N, 8.4. Found (%): C, 53.8; H, 4.0; N, 8.5. IR data
(KBr, cm-1): 3272 (m), 1643 (s), 1639 (s), 1486 (s), 1413
Considerable attention has been focused on the hydrazones
for their excellent biological properties, such as anti-
microbial, anticonvulsant, analgesic, antiinflammatory,
H.-Y. Zhu (&)
Department of Chemistry and Chemical Engineering,
Baoji University of Arts and Sciences, Baoji 721013,
People’s Republic of China
e-mail: zhuzhuhaiyun@126.com
123

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J Chem Crystallogr (2011) 41:1785–1789
Br
yielding colourless block-shaped single crystals. The
crystals were filtered out and washed with methanol. Yiled:
220 mg (74%). Anal. Calcd. (%) for C16H14N2O4: C, 64.4;
H, 4.7; N, 9.4. Found (%): C, 64.2; H, 4.7; N, 9.5. IR data
(KBr, cm-1): 3211 (m), 1648 (s), 1602 (s), 1540 (m), 1504
(m), 1456 (m), 1417 (w), 1350 (m), 1283 (m), 1245 (s),
1177 (m), 1110 (w), 1063 (w), 1024 (m), 953 (w), 912 (w),
845 (m), 827 (w), 760 (w), 683 (m), 617 (w), 525 (w),
460 (w).
O
O
O
O
H
H
N
N
N
N
O
O
Scheme 1 The hydrazone compounds
(m), 1351 (m), 1294 (m), 1266 (s), 1240 (s), 1182 (w),
1160 (w), 1110 (m), 1015 (m), 898 (w), 860 (w), 823 (w),
746 (m), 698 (w), 657 (w), 579 (w), 536 (w), 460 (w).
X-Ray Crystallography
X-ray diffraction intensities were collected using a Bruker
Apex II CCD area detector equipped with graphite-mono-
Synthesis of N0-(2-Methoxybenzylidene)-3,4-
methylenedioxybenzohydrazide (2)
´
˚
chromated Mo-Ka radiation (k = 0.71073 A) at 298(2) K.
Absorption corrections were applied by SADABS program
[9]. The structures were solved by direct methods and
refined on F2 by full-matrix least-squares methods using
the SHELXTL package [10]. All non-hydrogen atoms were
refined anisotropically. The amino H atom in compound (2)
was located in a difference Fourier map and refined
2-Methoxybenzaldehyde (135 mg, 1.0 mmol) and 3,4-(me-
thylenedioxy)benzohydrazide (180 mg, 1.0 mmol) were
mixed and stirred in methanol (100 mL) for 1 h at ambient
temperature to give a colourless solution. The solution was
left to slow evaporation of the methanol for 5 days,
Table 1 Crystal data, data
Compound
(1)
(2)
collection and structure
refinement for the compounds
Molecular formula
C15H13BrN2O2
333.2
C16H14N2O4
298.3
Molecular weight
Crystal system
Space group
Triclinic
P1
Tetragonal
P41
Temperature (K)
´
298(2)
298 (2)
˚
a (A)
8.4088(5)
8.5398(5)
10.6572(6)
90.356(3)
102.868(3)
97.987(3)
738.28(7)
2
9.792(4)
9.792(4)
15.788(6)
´
˚
b (A)
´
˚
c (A)
a (°)
b (°)
c (°)
´
3
˚
V (A )
1513.8(10)
Z
4
Dcalc (g cm-3
)
1.499
1.309
Crystal dimensions (mm)
Absorption coefficient (mm-1
Radiation k
0.20 9 0.20 9 0.18
2.786
0.17 9 0.15 9 0.15
)
0.096
´
´
˚
˚
Mo Ka(0.71073 A)
Mo Ka(0.71073 A)
Tmin/Tmax
0.606/0.634
0.984/0.986
Reflections measured
Range/indices (h, k, l)
h limit (°)
4456
4757
-10, 10; -10, 10; -13, 12
-12, 8; -12, 6; -19, 19
1.96–26.99
2.45–27.00
Total no. of unique data
3768 [Rint = 0.0295]
1706 [Rint = 0.0296]
No. of observed data, I [ 2r(I)
No. of variables
2248
1211
364
217
No. of restraints
3
2
Goodness of fit on F2
R1, wR2 [I C 2r(I)]a
R1, wR2 (all data)a
0.977
1.003
P
P
a
R1 = ||Fo|—|Fc||/ |Fo|,
wR2 = [ w(Fo2-Fc2)2/
0.0406, 0.0804
0.0914, 0.0992
0.0415, 0.0818
0.0672, 0.0928
P
P
w(Fo2)2]1/2
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J Chem Crystallogr (2011) 41:1785–1789
1787
˚
3-bromobenzohydrazide and 3,4-(methylenedioxy)benzo-
hydrazide, respectively, in methanol. The element analyses
are in good agreement with the formulae proposed for the
compounds. The single crystals of both compounds are
stable in air for at least 3 months, soluble in methanol,
ethanol, acetonitrile, chloroform, and dichloromethane,
insoluble in water.
Table 2 Selected bond lengths (A) and bond angles (°) for the
compounds
(1)
˚
Distances (A)
C8–N2
1.265(7)
1.339(8)
1.267(8)
1.347(8)
N1–N2
C7–O1
N3–N4
C22–O3
1.391(7)
1.238(7)
1.384(6)
1.224(7)
C7–N1
C23–N4
C22–N3
Structure Description of the Compounds
Angles (°)
C3–C7–N1
N1–C7–O1
N1–N2–C8
C16–C22–O3
O3–C22–N3
N3–N4–C23
117.2(5)
122.5(6)
115.6(5)
121.4(6)
122.3(6)
116.9(5)
C3–C7–O1
C7–N1–N2
N2–C8–C9
C16–C22–N3
C22–N3–N4
N4–C23–C24
120.3(6)
118.1(5)
119.8(6)
116.3(6)
118.4(5)
118.3(6)
Figures 1 and 2 give perspective views of the compounds
(1) and (2), respectively. The structures of the two com-
pounds are very similar. The asymmetric unit of the
compound (1) consists of two hydrazone molecules con-
nected to each other by a N–HꢀꢀꢀO hydrogen bond. All the
bond lengths and angles in the two compounds are com-
parable to each other, and also comparable to those
observed in other hydrazone compounds [11–22]. The
bond lengths of C8=N2 and C23=N4 in (1) and C8=N1 in
(2) confirm them as double bonds. The bond lengths of C7–
N1 and C22–N3 in (1) and C9–N2 in (2) are relatively
short, suggesting some degree of delocalization in the
(2)
˚
Distances (A)
C8–N1
1.278(4)
1.349(4)
N1–N2
C9–O2
1.386(3)
1.231(3)
N2–C9
Angles (°)
C1–C8–N1
N1–N2–C9
N2–C9–O2
120.8(3)
118.8(2)
122.3(6)
C8–N1–N2
N2–C9–C10
O2–C9–C10
115.2(2)
116.0(3)
121.7(3)
˚
Table 3 Distances (A) and angles (°) involving hydrogen bonding of
the compounds
D–HꢀꢀꢀA
d
d
d
Angle
˚
˚
˚
(D–H, A) (HꢀꢀꢀA, A) (DꢀꢀꢀA, A) (D–HꢀꢀꢀA,°)
(1)
N3–H3ꢀꢀꢀO1i
N1–H1ꢀꢀꢀO3
(2)
0.86
0.86
2.15
2.20
2.910(6)
2.952(7)
148
146
N2–H2ꢀꢀꢀO2ii 0.897(10) 2.131(17)
Symmetry codes i x, 1 ? y, z; ii 1 -y, x, 1/4 ? z
2.941(3)
150(3)
Fig. 1 Molecular structure of (1) at 30% probability displacement.
N–HꢀꢀꢀO hydrogen bond is shown as a dashed line
˚
isotropically, with N–H distance restrained to 0.90(1) A,
2
and with Uiso(H) values fixed at 0.08 A . The remaining H
˚
atoms were placed in idealized positions and constrained to
ride on their parent atoms. The details of the crystallo-
graphic data are summarized in Table 1. Selected bond
lengths and angles are summarized in Table 2. Hydrogen
bonding interactions are listed in Table 3.
Results and Discussion
The compounds were readily synthesized by the reaction
of equimolar quantities of 2-methoxybenzaldehyde with
Fig. 2 Molecular structure of (2) at 30% probability displacement
123

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J Chem Crystallogr (2011) 41:1785–1789
Dihedral Perpendicular Perpendicular
Table 4 p–p interactions
Cg
Distance
between ring angle (8) distance of
distance of
Cg(J) on
˚
Cg(I) (A)
˚
centroids (A)
Cg(I) on
˚
Cg(J) (A)
(1)
Cg1ꢀꢀꢀCg2#1 3.734
Cg1ꢀꢀꢀCg4#2 4.979
Cg2ꢀꢀꢀCg3#3 4.995
Cg3ꢀꢀꢀCg1#4 5.951
Cg3ꢀꢀꢀCg4#2 4.362
Cg4ꢀꢀꢀCg2#1 5.748
(2)
1.23
70.38
58.11
59.34
22.88
69.19
3.494
0.535
1.362
0.512
3.929
0.522
3.517
4.685
4.748
4.123
2.894
5.211
Cg5ꢀꢀꢀCg6#5 4.577
Cg5ꢀꢀꢀCg6#6 5.822
Cg6ꢀꢀꢀCg6#7 5.903
Cg6ꢀꢀꢀCg7#1 3.698
Cg7ꢀꢀꢀCg5#8 4.747
7.79
83.19
89.33
6.51
3.406
1.059
0.080
3.384
1.292
3.446
5.052
3.923
3.489
4.200
Fig. 3 Molecular packing of (1), viewed along the b axis. Hydrogen
bonds are shown as dashed lines
89.42
Cg1, Cg2, Cg3, and Cg4 are the centroids of the C1–C2–C3–C4–C5–
C6, C9–C10–C11–C12–C13–C14, C16–C17–C18–C19–C20–C21,
and C24–C25–C26–C27–C28–C29 rings in (1), respectively. Cg5,
Cg6, and Cg7 are the centroids of the O3–C14–C13–O4–C16, C1–
C2–C3–C4–C5–C6, and C10–C11–C12–C13–C14–C15 rings in (2),
respectively. Symmetry codes #1 -1 ? x, y, z; #2 x, y, 1 ? z; #3 x,
-1 ? y, -1 ? z; #4 1 ? x, 1 ? y, z; #5 1 ? x, y, z; #6 1-y, 1 ? x,
1/4 ? z; #7 y, -x, -1/4 ? z; #8, y, 2-x, -1/4 ? z
Fig. 4 Molecular packing of (2), viewed along the c axis. Hydrogen
bonds are shown as dashed lines
Conclusions
In the above study, two new hydrazone compounds have
been prepared, and their structures were confirmed by
elemental analysis, IR spectra, and single crystal
determination.
acetohydrazide systems. In (1), the dihedral angle between
the C1–C6 and C9–C14 benzene rings is 1.2(5)°, and that
between the C16–C21 and C24–C29 benzene rings is
22.9(5)°. In (2), the dihedral angle between the C1–C6 and
C10–C15 benzene rings is 6.5(3)°.
Supplementary Material
In the crystal structure of (1), molecules are linked
through N–HꢀꢀꢀO hydrogen bonds, forming chains running
along the b axis (Fig. 3). In the crystal structure of (2),
molecules are linked through N–HꢀꢀꢀO hydrogen bonds,
forming chains running along the c axis (Fig. 4). In both
structures, there are also short p-electron ring—p-electron
CCDC—782447 for (1) and 782448 for (2) contain the
supplementary crystallographic data for this paper. These
data can be obtained free of charge at http://www.ccdc.
cam.ac.uk/const/retrieving.html or from the Cambridge
Crystallographic Data Centre (CCDC), 12 Union Road,
Cambridge CB2 1EZ, UK; fax: ?44-1223-336033 or
e-mail: data_request@ccdc.cam.ac.uk.
˚
ring interactions with Cg–Cg distances\6.0 A and
b \ 60.0° that are specified in Table 4 [23].
Acknowledgments This work was supported by the Natural Sci-
ence Foundation of Shaanxi Province (Grant no. 2010JS068) and the
Science Research Foundation of Baoji University of Arts and Sci-
ences (Grant no. ZK085).
IR Spectra
The middle and sharp bands at 3272 cm-1 for (1) and
3211 cm-1 for (2) are assigned to m(N–H). The strong
bands at 1643 cm-1 for (1) and 1648 cm-1 for (2) are due
to m(C=O). The characteristic C=N stretching vibrations
of Schiff bases are at 1637 cm-1 for (1) and 1639 cm-1 for
(2), respectively.
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