Synthesis and crystal structure of (E)-1-(2,3-dihydroxybenzlidene)-4,4- dimethythiosemicarbazide

Article abstract of DOI:10.1007/s10870-011-0119-2

The Schiff base C₁₀H₁₃N₃O₂S is monoclinic, having unit cell parameters a = 9.788(1) A, b = 9.615(1) A, c = 12.605(1) A, β = 108.41(1)° and V = 1125.56(2) A³ and belongs to P2_1/n space group. The molecule is almost planar. The two hydroxyl groups present on the phenyl ring are involved in intermolecular H-bonding, which results in the stacking of molecules in the anti-parallel fashion leading an interesting network of channels. Besides this C-H...π and π-π (edge to edge) interactions appear to provide stability to the crystal lattice.

Full text of DOI:10.1007/s10870-011-0119-2

J Chem Crystallogr (2011) 41:1447–1450
DOI 10.1007/s10870-011-0119-2
ORIGINAL PAPER
Synthesis and Crystal Structure of (E)-1-(2,3-
Dihydroxybenzlidene)-4,4-Dimethythiosemicarbazide
•
Ajay Pal Singh Pannu Maninder Singh Hundal
Received: 29 September 2008 / Accepted: 30 April 2011 / Published online: 24 May 2011
Ó Springer Science+Business Media, LLC 2011
Abstract The Schiff base C10H13N3O2S is monoclinic,
˚
having unit cell parameters a = 9.788(1) A, b = 9.615(1)
by the condensation of the N(4)-phenylthiosemicarbazide
with the salicylaldehyde [7]. In these cases deprotonation
of the ring hydroxyl group also takes place along with the
loss of proton from the nitrogen of the thiosemicarbazide
moiety, enabling the ligand to act as ONS tridentate
ligands. A number of such mononuclear and dinuclear
transition metal complexes of these ligands have been
studied recently [1, 8]. A similar condensation reaction
between 2,3-dihydroxybenzaldehyde and thiosemicarba-
zide furnishes the corresponding Schiff base 2,3-dihy-
droxybenzaldehyde thiosemicarbazone [9, 10] which
posses two hydroxyl groups on the aromatic ring. The
compound crystallizes as a hemihydrate [11]. Herein, we
report the synthesis and crystal structure of 2,3-dihydr-
oxybenzaldehye 4,4-dimethyl-3-thiosemicarbazone.
˚
˚
A, c = 12.605(1) A, b = 108.41(1)° and V = 1125.56(2)
3
˚
A
and belongs to P21/n space group. The molecule is
almost planar. The two hydroxyl groups present on the
phenyl ring are involved in intermolecular H-bonding,
which results in the stacking of molecules in the anti-par-
allel fashion leading an interesting network of channels.
Besides this C–H_p and p–p (edge to edge) interactions
appear to provide stability to the crystal lattice.
Keywords 2,3-Dihydroxybenzaldehyde Á Thione Á
Thiolate Á Antiparallel Á p Interactions
Introduction
Condensation of an aldehyde or a ketone with thiosemi-
carbazide yields the thiosemicarbazone of the correspond-
ing aldehyde or ketone. These thiosemicarbazones have
attained considerable importance due to the pharmacolog-
ical properties of their transition metal complexes [1–4]. As
ligands thiosemicarbazones usually bind to a metal ion
either in the thione form or in the thiolate form as bidentate
ligands forming 5 membered chelate rings [1–5].
Experimental
Thiosemicarbazide (1.19 g, 10 mmol) in 15 mL ethanol
was added to a solution of 2,3-dihydroxybenzaldehyde
(1.38 g, 10 mmol) in 25 mL in boiling water. The mixture
was refluxed for 4 h until the light brown solid settled
down. Recrystallization from methanol gave light brown
crystals. The data were collected at 298 K on a Siemens P4
single crystal X-ray diffractometer using the XSCANS
package [12]. A suitable crystal of the size 0.1 9 0.1 9
0.2 mm was carefully mounted on the goniometer. The
h–2h scan mode was used to measure the intensities, up to
a maximum of 2h = 51°, using graphite monochromatised
In case of thiosemicarbazones of aromatic o-hydrox-
yaldehydes the coordination to the metal ion is in tridentate
fashion. Salicylaldehyde condenses with thiosemicarbazide
to form salicylaldehyde thiosemicarbazone [6]. Similarly
salicylaldehyde N(4)-phenylthiosemicarbazone is obtained
˚
Mo Ka radiations (k = 0.71073 A). To monitor the sta-
bility of the crystal 3 standard reflections were measured
after every 97 reflections. A total of 2219 reflections were
measured out of which 2092 were unique and 1511 were
considered observed [I [ 2r(I)]. The data were corrected
A. P. S. Pannu Á M. S. Hundal (&)
Department of Chemistry, Guru Nanak Dev University,
Amritsar 143005, India
e-mail: hundal_chem@yahoo.com
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Table 1 Crystal data and structure refinement for the compound
Empirical formula
Formula weight
C10H13N3O2S
239.29
Temperature
295(2) K
˚
0.71073 A
Wavelength
Crystal system, space group
Unit cell dimensions
Monoclinic, P21/n
˚
a = 9.788(1) A
˚
b = 9.615(1) A
c = 12.605(1)
b = 108.41(1)°
3
˚
Volume
1125.56(2) A
Fig. 1 Showing the molecular structure and the labeling scheme used
with 30% ellipsoidal probability
Z, Calculated density
Absorption coefficient
F(000)
4, 1.412 Mg/m3
0.277 mm-1
504
˚
Table 2 Important bond lengths (A) and angles (°)
Crystal size
0.20 9 0.10 9 0.10 mm
C(4)–O(2)
C(4)–C(5)
C(5)–O(1)
C(5)–C(6)
C(6)–C(7)
C(7)–N(1)
C(8)–N(3)
C(8)–N(2)
C(8)–S(1)
C(9)–N(3)
C(10)–N(3)
N(1)–N(2)
1.371(2)
1.395(3)
1.357(2)
1.407(3)
1.451(3)
1.276(3)
1.338(3)
1.362(3)
1.691(2)
1.459(3)
1.464(3)
1.373(3)
C(7)–N(1)–N(2)
C(8)–N(2)–N(1)
C(8)–N(3)–C(9)
C(8)–N(3)–C(10)
C(9)–N(3)–C(10)
N(2)–C(8)–S(1)
N(3)–C(8)–S(1)
N(3)–C(8)–N(2)
N(1)–C(7)–C(6)
O(1)–C(5)–C(4)
O(1)–C(5)–C(6)
O(2)–C(4)–C(5)
117.1(2)
119.5(2)
121.9(2)
122.5(2)
115.6(2)
121.2(2)
123.1(2)
115.7(2)
120.8(2)
117.3(2)
123.4(2)
116.3(2)
Theta range for data collection
Limiting indices
2.31–25.50°
0 B h B 11, 0 B k B 11,
-15 B l B 14
Reflections collected/unique
Completeness to theta = 25.50
Max and Min transmission
Refinement method
2219/2092 [R(int) = 0.0186]
100.0%
0.9728 and 0.9467
Full-matrix least-squares on F2
2092/0/145
Data/restraints/parameters
Goodness-of-fit on F2
1.020
Final R indices [I [ 2r(I)]
R indices (all data)
R1 = 0.0432, wR2 = 0.1252
R1 = 0.0596, wR2 = 0.1329
-3
˚
Largest diff. peak and hole
CCDC number
0.330 and -0.282 e A
703182
phenyl ring containing two ortho hydroxyl groups along
with an aliphatic side chain bonded to C6 (Fig. 1). The
mean plane calculations show that a plane can be passed
through the phenyl ring along with its two hydroxyl oxy-
gens with a maximum deviation of 0.03° for carbon C(6)
from the plane. Similarly leaving out the two methyl
groups a plane can be passed through the thiosemicarba-
zide moiety attached to the atom C(6) of the ring. The
methyl carbon C(9) is 0.16° above while the other methyl
carbon C(10) is 0.11° below the above mentioned plane.
The C(1)–C(6)–C(7)–N(1) torsion angle of -178° shows
that the entire molecule is almost planar.
for Lorentz and polarization effects. The structure was
solved by direct methods using SIR97 [13] and refined by
Full-matrix least-squares refinement techniques on F2
using SHELXL-97 [14] in the Wingx package [15] of
programs. All atoms were refined anisotropically. The
hydrogen atoms attached nitrogen N(2), oxygens O(1) and
O(2) were located by difference Fourier syntheses and were
not refined. They were assigned an isotropic thermal
parameter of 0.05. All other hydrogen atoms were fixed
geometrically and during refinement they were allocated
Uiso 1.5, 1.2 and 1.2 times the Uiso of their carrier methyl,
methylene and aromatic carbon atoms, respectively.
Table 1 gives the crystal data and refinement details of the
title compound.
The molecule exists in thione form as solid as is evident
˚
from carbon sulfur bond length [1.691(2) A] resembling
closer proximity with the carbon sulfur double bond
˚
[1.71(1) A] character rather than their single bond
˚
[1.82(1) A] [7]. The N1–N2 bond length of 1.373(3) A and
˚
˚
N2–C8 bond length of 1.359(3) A which are in between the
Results and Discussion
˚
values of single N–N [1.45 A], C–N [1.47 A] and double
˚
˚
˚
Figure 1 shows the molecular structure and the numbering
scheme used for the title compound. Important bond
lengths and bond angles are summarized in Table 2.
Crystal structure of the molecule shows that it consist of a
N=N [1.25 A], C=N [1.28 A] respectively [7]. This short-
ening is probably due to delocalization of p electron cloud
over the C7–N1–N2–C8–S1 fragment. The conforma-
tion around the C(7)=N(1) bond is E as indicated by the
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C(6)–C(7)–N(1)–N(2) torsion angle of 178.2° with the C(6)
and N(2) atoms in cis orientation with respect to the double
bond [7, 11, 16].
The torsion angle N(1)–N(2)C(8)–S(1) of -7.9° indi-
cates that the atoms N(1) and S(1) are cis to each other with
respect to C(8)–N(2) bond which is just the opposite to what
has been observed in earlier similar reports [7, 11, 16]. In all
such similar reports the above mentioned torsion angle
comes to out be close to 180° thus orienting the S(1) and
N(1) in trans conformation with respect to the C(8)–N(2)
bond. All other bond angles and bond lengths are normal in
accordance with the similar earlier reports [11, 17].
Crystal packing diagrams reveals that the molecule is
involved in both intra as well as intermolecular H-bonding
interactions. The H-bonding interactions are described in
Table 3. The nitrogen N1 is an acceptor in the O1_H12–
N1, intramolecular H-bond (Fig. 2).
Fig. 3 Showing the intermolecular H-bonding interactions
The oxygen O2 of one molecule is an acceptor to
hydrogen bonds C10–H10C_O2, C21–H21_O2 and
C7–H7_O2 with the neighboring molecule. The mean
planes of these two molecules are almost perpendicular
to each other, thus forming a ladder type arrangement
(Figs. 3, 4).
The packing diagram shows that each of these neighboring
molecules is also involved in stacked arrangement of mole-
cules in their respective planes. In this type of arrangement the
˚
Table 3 Hydrogen bond geometry (A, °)
D–H_A
H_A
D_A
D–H_A
O1–H12_Ni
1.78
2.62
2.54
2.09
2.73
2.71
2.12
2.632(2)
3.280(3)
3.273(4)
2.915(2)
3.489(3)
3.556(3)
3.121(2)
145
128
134
146
137
148
170
C7–H7_O2ii
C10–H10C_O2ii
N2–H21_O2ii
C10–H10B_O1ii
C10–H10C_O1iii
O2–H11_S1iv
i = x, y, z; ii = x ? 1/2, -y ? 1/2, ?z ? 1/2; iii = -x ? 2,
-y ? 1, -z ? 1; iv = -x ? 1/2 ? 1, ?y - 1/2, -z ? 1/2; v =
-x ? 1/2 ? 1, ?y ? 1/2, -z ? 1/2
Fig. 4 showing the ladder formation due to intermolecular
H-bonding
molecules are lying approximately over each other in an anti-
parallel fashion. Two such successive molecules are held
together by the C10–H10C_O1 hydrogen bonds along with
C–H_p interactions behaving as a dimeric unit (Fig. 5).
These successive dimers are further held together by the p_p
(edge to edge) interactions which appear to be stabilizing the
entirestackedlattice, leading toa networkofchannelsrunning
parallel to their respective planes (Fig. 6).
Fig. 2 Showing the intramolecular H-bonding interaction involving
one of the hydroxyl groups
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J Chem Crystallogr (2011) 41:1447–1450
Acknowledgment A. P. S. Pannu is grateful to the University
Grants Commission for research fellowship.
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Fig. 6 Showing the formation of channels along the ab plane
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