Synthesis and crystal structures of two new Schiff base hydrazones derived from biphenyl-4-carbohydrazide

Article abstract of DOI:10.1007/s10870-011-0118-3

The crystal structures of two novel Schiff base hydrazones have been determined by means of the X-ray diffraction. These compounds: N′-[(E)-(2,5-dimethoxyphenyl)methylidene]biphenyl-4-carbohydrazide, C ₂₂H₂₀N₂O₃

Full text of DOI:10.1007/s10870-011-0118-3

J Chem Crystallogr (2011) 41:1442–1446
DOI 10.1007/s10870-011-0118-3
ORIGINAL PAPER
Synthesis and Crystal Structures of Two New Schiff Base
Hydrazones Derived from Biphenyl-4-Carbohydrazide
•
Grzegorz Dutkiewicz B. Narayana
•
•
S. Samshuddin H. S. Yathirajan Maciej Kubicki
•
Received: 21 February 2011 / Accepted: 29 April 2011 / Published online: 10 May 2011
Ó The Author(s) 2011. This article is published with open access at Springerlink.com
Abstract The crystal structures of two novel Schiff base
hydrazones have been determined by means of the X-ray dif-
fraction. These compounds: N0-[(E)-(2,5-dimethoxyphenyl)
methylidene]biphenyl-4-carbohydrazide, C22H20N2O3 (1)
and N0-[(E)-(4-fluorophenyl)methylidene]biphenyl-4-car-
bohydrazide, C20H15FN2O (2), are the first structurally
characterized biphenyl derivatives of phenylmethylidene-
carbohydrazide. Both compounds crystallize in the
monoclinic space groups, 1 in P21/c space group with
interactions, are however quite different: in 1 there are
almost solely dispersion van der Waals interactions while
in 2 some more specific C–HꢀꢀꢀF and C–Hꢀꢀꢀp interactions
are also involved in the crystal packing.
Keywords Schiff bases ꢀ Hydrazones ꢀ Crystal structure ꢀ
Weak interactions
˚
˚
˚
a = 13.987(2) A, b = 16.426(3) A, c = 8.214(2) A, b =
Introduction
˚
98.12(2)°, and 2 in C2/c with a = 37.163(5) A, b =
˚
˚
10.696(2) A, c = 8.098(2) A, b = 101.18(2)°. Both mol-
ecules have very similar bond lengths and angles pattern,
even in the differently substituted phenyl ring. However,
the conformations of the molecules differ significantly, the
more crowded molecule 1 is much more folded than 2. The
dihedral angle between the terminal ring planes is
56.17(6)° in 1 while in 2 it is as small as 2.83(14)°. In both
structures relatively short and linear N–HꢀꢀꢀO hydrogen
bonds (created by the best available hydrogen bond donor
and acceptor) connect molecules into the chains along the
Schiff base hydrazones play an important role in inorganic
chemistry, as they easily form stable complexes with most
transition metal ions. The development of the field of
bioinorganic chemistry has increased the interest in Schiff
base complexes, since it has been recognized that many of
these complexes may serve as models for biologically
important species (e.g. [1, 2]). Coordination compounds
derived from aroylhydrazones have been reported to act as
enzyme inhibitors and are useful due to their pharmaco-
logical applications (e.g. [3–5]).
˚
unit cell parameter of ca. 8 A in length. The next stage of
Hydrazones containing an azomethine –NHN=CH–
proton are synthesized by heating the appropriate substi-
tuted hydrazines/hydrazides with aldehydes and ketones in
solvents like ethanol, methanol, tetrahydrofuran, butanol,
glacial acetic acid, ethanol–glacial acetic acid. Another
synthetic route for the synthesis of hydrazones is the cou-
pling of aryldiazonium salts with active hydrogen com-
pounds [6].
the crystal architecture determination, the secondary
G. Dutkiewicz ꢀ M. Kubicki (&)
Department of Chemistry, Adam Mickiewicz University,
Grunwaldzka 6, 60-780 Poznan, Poland
e-mail: mkubicki@amu.edu.pl
In course of our studies on the different medium and weak
interactions that are responsible for the crystal packing we
have synthesized and solved the crystal structures of two new
Schiff bases, namely N0-[(E)-(2,5-dimethoxyphenyl)methyli-
dene]biphenyl-4-carbohydrazide, C22H20N2O3 (1) and N0-
[(E)-(4-fluorophenyl)methylidene]biphenyl-4-carbohydrazide,
B. Narayana ꢀ S. Samshuddin
Department of Studies in Chemistry, Mangalore University,
Mangalagangotri 574 199, India
H. S. Yathirajan
Department of Studies in Chemistry, University of Mysore,
Manasagangotri, Mysore 570 006, India
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J Chem Crystallogr (2011) 41:1442–1446
1443
separated was filtered, washed with water and dried. Good
quality crystals were grown from DMF solution by slow
evaporation (m.p.: 495 K). Composition: Found (Calcu-
lated): C: 38.39 (38.47); H: 3.17 (3.23); N: 22.35%
(22.43%).
Synthesis of N0-[(E)-(4-fluorophenyl)methylidene]
biphenyl-4-carbohydrazide (2)
Biphenyl-4-carbohydrazide (0.01 mol, 2.12 g) and 4-fluoro
benzaldehyde (1.24 g, 0.01 mol) were dissolved in ethanol
(30 mL) and added two drops of Conc. HCl. Refluxed the
mixture for about 3 h. On cooling, the solid separated was
filtered, washed with water and dried. Good quality crystals
were grown from DMF solution by slow evaporation (m.p.:
519 K). Composition: Found (Calculated): C: 75.39(75.46);
H: 4.68 (4.75); N: 8.74% (8.80%).
Scheme 1 Structures of Schiff base hydrazones
C20H15FN2O (2), cf. Scheme 1. Although there is a number
of crystal structures of benzaldehyde-benzoylhydrazone
derivatives (the Version 5.31 of the Cambridge Structural
Database [7] updated November 2010 produces 257 hits
containing this structural fragment) to the best of our
knowledge the compounds described here are the first
examples of biphenyl-containing derivatives.
X-ray Structure Determination
Because the packing of the molecules in crystals results
as the compromise between different factors including e.g.
intermolecular interactions, studying of the packing regu-
larities and differences in the crystals built of similar
molecules might be useful in the area of supramolecular
chemistry (e.g. [8, 9] and references therein). In both 1 and
2 one can find one good hydrogen bond donor (NH) and
one C=O group that might act as hydrogen bond acceptor.
Therefore it could be anticipated that the main packing
motif is a chain of hydrogen bond molecules, probably
related by a screw axis or a glide plane. However the
packing of the chains has to be determined by other
interactions and requirements, which in this case would be
among such factors as close packing, van der Waals
interactions, weak hydrogen bonds (C–HꢀꢀꢀO, F, N or p),
p–p stacking etc. Studies on such closely related but dif-
ferent systems might be useful in gaining the better
understanding of the factors that influence the crystal
packing.
Diffraction data were collected at room temperature by the
x-scan technique, on an Oxford Diffraction SuperNova
four-circle diffractometer equipped with Atlas CCD-
detector [10] using mirror-monochromatized CuKa radia-
˚
tion from high-flux micro-focus source (k = 1.54178 A).
The data were corrected for Lorentz-polarization as well as
for absorption effects [10]. Accurate unit-cell parameters
were determined by a least-squares fit of 5001 (1), and 7561
(2) reflections of highest intensity, chosen from the whole
experiment. The structures were solved with SIR92 [11] and
refined with the full-matrix least-squares procedure on F2 by
SHELXL97 [12]. Scattering factors incorporated in SHEL-
2
2 2
XL97 were used. The function Rw(jFoj - jFcj ) was
minimized, with w-1 = [r2(Fo)2 ? (AP)2 ? BP], where
P = [Max (F2o, 0) ? 2F2c/3]. The final values of A and B are
listed in Table 1 together with relevant crystal data and
refinement details. All non-hydrogen atoms were refined
anisotropically. The hydrogen atoms from the methyl groups
in 1 were placed geometrically, in idealized positions (C–H
˚
distances of 0.96 A), and refined as rigid groups with their
Experimental
U
iso’s as 1.5 times Ueq of the appropriate carrier atom. All
other hydrogen atoms were found in the difference Fourier
maps and isotropically refined.
Synthesis
Crystallographic data (excluding structure factors) for
the structural analysis has been deposited with the Cam-
bridge Crystallographic Data Centre, Nos. CCDC-813832
(1), and CCDC-813833 (2). Copies of this information
may be obtained free of charge from: The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK. Fax:
?44(1223)336-033, e-mail:deposit@ccdc.cam.ac.uk, or
www: www.ccdc.cam.ac.uk.
Synthesis of N0-[(E)-(2,5-dimethoxyphenyl)
methylidene]biphenyl-4-carbohydrazide (1)
Biphenyl-4-carbohydrazide (0.01 mol, 2.12 g) and 2,5-
dimethoxy benzaldehyde (1.66 g, 0.01 mol) were dissolved
in ethanol (30 mL) and added two drops of Conc. HCl.
Refluxed the mixture for about 3 h. On cooling, the solid
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J Chem Crystallogr (2011) 41:1442–1446
Table 1 Crystal data, data collection and structure refinement
Compound
Formula
1
2
C
22H20N2O3
C20H15FN2O
318.34
Formula weight
Crystal system
Space group
T (K)
360.40
Monoclinic
P21/c
Monoclinic
C2/c
295(2)
295(2)
˚
a (A)
13.987(2)
16.426(3)
8.214(2)
98.12(2)
1868.3(6)
4
37.163(5)
10.696(2)
8.098(2)
101.18(2)
3157.8(11)
8
Fig. 1 Anisotropic ellipsoid representation of the compound 1
together with atom labeling scheme [11]. The ellipsoids are drawn
at 50% probability level, hydrogen atoms are shown as spheres of
arbitrary radii
˚
b (A)
˚
c (A)
b (°)
3
˚
V (A )
Z
Dx (g cm-3
F(000)
)
1.28
1.34
760
1328
l (mm-1
)
0.70
0.75
Crystal size (mm)
0.3 9 0.1 9 0.1
3.19–75.09
-17 B h B 10
-20 B k B 18
-10 B l B 9
0.3 9 0.2 9 0.15
4.31–75.06
-46 B h B 41
-13 B k B 8
-10 B l B 9
H range (°)
hkl range
Fig. 2 Anisotropic ellipsoid representation of the compound 2
together with atom labeling scheme [11]. The ellipsoids are drawn
at 50% probability level, hydrogen atoms are shown as spheres of
arbitrary radii
Reflections
Collected
7161
8344
Unique (Rint
)
3690 (0.013)
3239
3156 (0.025)
2974
With I [ 2r(I)
Number of parameters
Weighting scheme
A
302
278
˚
Table 2 Selected geometrical parameters (A, °) with su’s in
parentheses
0.0638
0.1742
0.040
0.0499
3.4051
0.060
1
2
B
C1–C7
1.491(4)
1.218(3)
1.478(4)
1.326(4)
1.452(4)
1.483(5)
1.210(4)
1.484(5)
1.328(4)
1.449(4)
R(F) [I [ 2r(I)]
wR(F2) [I [ 2r(I)]
R(F) [all data]
wR(F2) [all data]
Goodness of fit
C7–N8
0.110
0.141
N8–N9
0.044
0.061
N9–C10
0.113
0.142
C10–O11
1.056
1.071
-3
˚
C15–C18
Max/min Dq (e A
)
0.14/-0.17
0.20/-0.21
C1–C2–C3
C2–C3–C4
C3–C4–C5
C4–C5–C6
C5–C6–C1
C6–C1–C2
C1–C7–N8
C7–N8–N9
C2–C1–C7–N8
C1–C7–N8–N9
C7–N8–N9–C10
N8–N9–C10–C12
N9–C10–C12–C13
C14–C15–C18–C19
B/C
119.3(3)
120.8(3)
129.2(3)
120.4(3)
121.5(3)
118.3(3)
120.1(3)
122.4(3)
117.7(3)
122.0(3)
128.3(3)
121.0(3)
118.5(4)
122.8(4)
118.1(4)
121.6(4)
168.09(19)
177.06(17)
Results
Figures 1 and 2 show the perspective views of the mole-
cules 1 and 2, respectively. Table 2 compares the relevant
geometric parameters of both molecules. The bond lengths
and angles in both compounds are very similar; a majority
of them differ by less than 3r, and even the results of the
normal probability plot test [13, 14] confirm that the dif-
ferences between the molecules are mainly of statistic
nature.
The correlation coefficient R2 between the set of
experimental differences between the geometrical param-
eters and the theoretical values for pure statistical distri-
bution is 0.967 for the bond lengths (excluding C14–C141
and C14–F14 bonds) and 0.984—for angles. Of course the
-158.07(12)
-176.66(11)
-155.61(12)
-178.09(10)
-138.94(13)
-34.02(21)
33.48(5)
-176.37(18)
176.33(16)
-147.98(19)
-23.3(3)
23.14(10)
A/C
56.17(6)
2.83(14)
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J Chem Crystallogr (2011) 41:1442–1446
1445
different substituents in ring A cause the differences in the
intraannular bond angles patterns—as observed for
instance by Domenicano and Murray-Rust [15, 16]—but it
seems that in this case, due to the various positions of these
substituents, the differences mainly cancel out.
there is enough space for methoxy group to accommodate
and the CSD data do not show the clear conformational
preferences. The overall shape of these molecules can be
described by the dihedral angles between three planar
fragments (cf. Fig. 1 for the nomenclature; Table 2 for
appropriate values). In 1 the central C=N–N–C=O chain is
relatively far from the planarity, the atoms N8, N9, C10,
The overall conformations of 1 and 2 differ, and it can
be related to the presence or absence of the substituent in
the ortho position of the ring A, even though it seems that
˚
O11 and C12 are coplanar within 0.018 A while N7
˚
deviates from that mean plane by as much as 0.488(2) A.
This mean plane makes the dihedral angle of 50.68(6)°
with the plane of ring A and 39.92(5)° with that of ring B.
In 2 the whole C=N–N–C=O chain is planar within
˚
0.019(1) A, and it makes similar to previously given
dihedral angle with B, 33.32(15)°, while the twist with
respect to the ring A is significantly smaller, 12.89(15)°.
The biphenyl fragments in both molecules are twisted but
also in this case the twist angle is greater in 1, the dihedral
angle between mean planes of phenyl rings is 33.48(5)° in
1 and 23.14(10)° in 2. The terminal rings A and C are
significantly twisted in 1 (56.17(6)°) while they are almost
coplanar in 2 (2.83(14)°). The comparison of both
Fig. 3 The comparison of the molecules of 1 (dashed) and 2 (solid);
the rings A were fitted onto one another [11]
Fig. 4 The hydrogen bonded chains of molecules 1 (a) and 2 (b) as seen approximately along y direction. Hydrogen bonds are shown as dashed
lines [11]
Table 3 Hydrogen bond data
˚
D–H(A)
˚
˚
D
H
A
HꢀꢀꢀA(A)
DꢀꢀꢀA(A)
D–HꢀꢀꢀA(°)
1
N9
H9
O11i
0.883(17)
1.999(18)
2.8729(15)
169.9(15)
2
N9
H9
O11ii
F4iii
CgAiv
CgCv
ii
0.86(2)
0.94(2)
0.93(2)
0.93(2)
iii
2.05(2)
2.67(2)
2.85(2)
2.91(2)
iv
2.906(2)
3.458(3)
3.609(3)
3.656(3)
v
170(2)
C5
H5
142.4(19)
140.2(17)
137.2(18)
C19
C22
H19
H22
i
Symmetry codes: x, -y ? 1/2, z ? 1/2; x, 2 - y, z ? 1/2; 1 - x, 2 - y, -z; 3/2 - x, 1/2 ? y, 1/2 - z; x, 2 - y, 1/2 ? z
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J Chem Crystallogr (2011) 41:1442–1446
Fig. 5 The crystal packing as seen along the direction of hydrogen bonded chains in 1 (a) and 2 (b) [11]
molecules, fitted onto their rings A, is shown in Fig. 3. The
geometries of both 1 and 2 are well within the typical
ranges.
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These quite closely related molecules turned out to show
to some extent different organisation in the crystal struc-
ture. As expected, in both cases the N–HꢀꢀꢀO hydrogen
bonds, relatively linear, connect molecules into the infinite
chains of molecules connected by the c-glide plane. In both
cases therefore the chains extend along [001] direction (cf.
Fig. 4a, b; Table 3), and in both structures—despite dif-
ferent space groups—the unit cell parameters c have sim-
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15. Domenicano A, Murray-Rust P (1979) Tetrahedron Lett 24:2283
16. Domenicano A (1988) In: Hargittai I, Hargittai M (eds) Stereo-
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˚
ilar values (8.214 A in 1, 8.098 A in 2).
˚
The next levels of the structure organizations are how-
ever different, which can be caused by the differences in
the molecular conformations. In 1 there are virtually no
specific interactions which might play a role in the
designing of the crystal structure. Therefore only close
packing requirements and van der Waals forces are
involved in the crystal structure. Contrary, in 2 there is
some weak but definitely directional C–HꢀꢀꢀF interactions,
and two—probably also of some importance—C–Hꢀꢀꢀp
contacts with aromatic rings playing role of very weak
acceptor of a hydrogen-bond-like interaction (cf. Table 3).
These subtle differences lead to quite dissimilar mode of
packing of the hydrogen-bonded chains (Fig. 5).
Acknowledgment BN thanks UGC, New Delhi, Government of
India for the purchase of chemicals through SAP-DRS-Phase 1
programme.
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