Crystal structure and properties of N-phenyl-N′-(2-nitrobenzoyl) thiourea

Article abstract of DOI:10.14233/ajchem.2013.14963

N-phenyl-N′-(2-nitrobenzoyl)thiourea has been synthesized in high yield under PEG-400 as the phase-transfer catalyst. The structure of the synthesized substituted thiourea was determined by single crystal X-ray diffraction. In DMSO solutions, L1 exhibited

Full text of DOI:10.14233/ajchem.2013.14963

Asian Journal of Chemistry; Vol. 25, No. 16 (2013), 9009-9012
http://dx.doi.org/10.14233/ajchem.2013.14963
Crystal Structure and Properties of N-Phenyl-N'-(2-nitrobenzoyl)thiourea
1,*
2
1
J.H. HU , Y. LI and N.P. YAN
1College of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu Province, P.R. China
2College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, Gansu Province, P.R. China
*Corresponding author: Tel: +86 13359460506; E-mail: hujinghan62@163.com
(Received: 12 December 2012;
Accepted: 13 September 2013)
AJC-14103
N-phenyl-N’-(2-nitrobenzoyl)thiourea has been synthesized in high yield under PEG-400 as the phase-transfer catalyst. The structure of
the synthesized substituted thiourea was determined by single crystal X-ray diffraction. In DMSO solutions, L1 exhibited selective
recognition for F–, OAc– and H2PO4–. In addition, the compound is also a considerable plant-growth regulator.
Key Words: Aroylthiourea, Anion recognition, Crystal structure, Biological activity.
Plus-400 MHz spectrometer with DMSO-d6 as solvent and
TMS as an internal reference. Electrospray ionization mass
spectra (ESI-MS) were measured on an Agilent 1100 LC-
MSD-Trap-VLsystem. Elemental analyses were performed by
Thermo Scientific Flash 2000 organic elemental analyzer.
All the UV-visible experiments were carried out in DMSO
on a Shimadzu UV-2550 spectrometer. Any changes in the
UV-visible spectra of sensor L1 were recorded upon the
addition of tetrabutylammonium salts while keeping the
concentration of sensor L1 constant in all experiments. The
solution of the sensor L1 (2.0 × 10-4 M) in DMSO was prepared
and stored in dry atmosphere. The solution was used for all
spectroscopic studies after appropriate dilution. Solutions of
1.0 × 10-2 mol L-1 tetrabutylammonium salts of the respective
anions were prepared.
Synthesis: N-Phenyl-N’-(2-nitrobenzoyl)thiourea was
synthesized in high yield was shown in Scheme-I: powdered
potassium thiocyanate (7.5 mmol) 2-nitrobenzoyl chloride (5
mmol), PEG-400 (3 % with respect to ammonium thiocyanate)
and dichloromethane 20 mL were placed in a dried round-
bottomed flask containing a magnetic stirrer bar and stirred at
room temperature for 1 h, then aniline (5 mmol) was added
and the mixture were stirred for additional 0.5 h. The corres-
ponding thiourea precipitates immediately. The product was
filtered, washed with water to remove inorganic salts, dried
and recrystallized from DMF-EtOH-H2O to give the title
compound. Yield, 78 %; m.p. 179-181 ºC; 1H NMR (CDCl3,
400 MHz) δ: 12.28 (s, 1H, NH), 11.62 (s, H, NH), 7.24-8.14
(m, 9H,Ar-H); 13C NMR (CDCl3, 400 MHz) δ: 124.25, 124.94,
127.09, 128.27, 128.86, 130.03, 131.93, 134.27, 137.18,
145.80, 166.68, 177.88; ESI-MS: 301.7 (m/z + 1). IR (KBr,
INTRODUCTION
The development of selective optical signaling systems
for anions has received considerable attention in recent decades
due to their important roles in biological and environmental
processes1. Since the first synthetic sensor for inorganic anions
was reported in 19682, great progress has been made3-5.
Recently, thiourea and its derivatives as neutral receptors have
been growing in the field of host-guest chemistry6,7. Among a
variety of possible H-bond donor groups, systems employing
thiourea moieties have been proven to be very efficient in the
design of neutral anion binding receptors8. We synthesized a
anion sensor bearing NH groups, in addition, in order to
achieve colorimetric recognition, we induced nitrophenyl
group as signal report group. The results show that it can be
used as anion sensor in DMSO, at the same time, by investi-
gating the biological activity of the title compound, we found
that the compound has high plant growth regulating activity
at low concentration.
EXPERIMENTAL
All reagents for synthesis were analytical grade, commer-
cially and were used without further purification.All the anions
were added in the form of tetrabutylammonium (TBA) salts,
which were purchased form Sigma-Aldrich Chemical, stored
in a vacuum desiccator.
Melting points were measured on an X-4 digital melting-
point apparatus (uncorrected). The infrared spectra were per-
formed on a Digilab FTS-3000 FT-IR spectrophotometer. UV-
VIS spectra were recorded on a Shimadzu UV-2550 spectro-
1
meter. H NMR spectra were recorded on a Varian Mercury

9010 Hu et al.
Asian J. Chem.
O
O
TABLE-2
PEG-400
+
KSCN
SELECTED BOND DISTANCES (nm) AND
BOND ANGLES (°) FOR THE COMPOUND
CH2Cl2 / r.t.
N C S
Cl
NO2
S
NO2
Bond lengths
S(1)-C(8)
C(2)-N(3)
C(7)-N(1)
C(8)-N(1)
1.650(2)
1.458(3)
1.367(3)
1.394(2)
C(1)-C(7)
C(7)-O(1)
C(8)-N(2)
C(9)-N(2)
1.508(3)
1.206(3)
1.316(3)
1.422(2)
O
NH2
N
H
N
H
CH2Cl2 / r.t.
NO2
Bond angles
L1
C(3)-C(2)-N(3)
C(7)-N(1)-C(8)
117.53(19)
128.70(19)
C(1)-C(2)-N(3)
C(8)-N(2)-C(9)
120.15(17)
129.25(19)
Scheme-I: Synthetic route of L1
νmax, cm-1): 3169, 3028 (NH), 1691 (C=O), 1258(C=S); anal.
calcd. (%) for C14H11N3SO3: C: 55.80, H: 3.68, N: 13.95; Found
C: 55.77, H: 3.70, N: 13.97.
Structure determination: The crystal structure of the title
compound atom scheme-labeling was shown in Fig. 1. The
crystal data and structure refinement details for C14H11N3O3S
are summarized in Table-1, selected bond distances and angles
are listed in Tables 2 and 3.
TABLE-3
DATA OF HYDROGEN BOND (nm)
AND ANGLE (°) OF TITLE COMPOUND
D-H
(nm)
H···A
(nm)
D···A
(nm)
D-H···A Symmetry
(º)
D-H···A
code
-x+1, -
y+1, -z+2
N2-
H2N···O1
–
–
2.698(6)
144. 8
Fig. 2 showed that the crystals were linked to one-dimen-
sional chain-like superamolecular through the intermolecular
hydrogen bonds, which form a eight-membered ring with C8A,
N1A, H1NA, S1C, C8C, N1C, H1NC, S1A. Moreover, it is
found that the supramolecular are connected by intermolecular
hydrogen bond of N(1C)-H(1NC)···S(1A) along the oc-axis
direction and parallel packing along the oa-axis direction. As
shown in Fig. 2, we can find the parallel packing of the phenyl
rings in the crystal of the compound; however, the distance
between the centers of two parallel phenyl rings is 0.6201 nm,
which is out of the accepted range of the intermolecular π-π
interaction9.
Fig. 1. Crystal structure of the title compound
TABLE-1
CRYSTAL DATA OF THE TITLE COMPOUND
Formula
f.w.
C14H11N3O3S
301.32
Crystal system,
Triclinic
Space group
P-1
a (Å)
b (Å)
c (Å)
α (º)
6.2013(4)
9.9667(6)
11.9444(8)
74.188(3)
85.421(3)
83.191(3)
704.42(8), 2
312
β (º)
γ (º)
V (Å3), Z
F(000)
Reflections collected/unique (Rint)
Obsd reflns [I ≥ 2σ(I)]
data/restraints/parameter
Dc (Mg m-3)
4293/2993 [R(int) = 0.0096]
2993
2993/0/198
1.421
0.243
1.051
µ (mm-1)
Goodness-of-fit on F2
Fig. 2. Packing diagram of the title compound
b
R1,a wR2 [I ≥ 2σ(I)]
0.0471, 0.1381
RESULTS AND DISCUSSION
Anion recognition properties: Compound L1 (2 × 10-5 M)
exhibited strong absorption at 303 nm in DMSO solution.
When adding 50 equiv of F–, OAc–, H2PO4– to the DMSO
solution of L1 (Fig. 3), it indicated that the receptor L1 exhi-
bited selective recognition for F–, OAc– and H2PO4– in DMSO.
The same test were applied to Cl–, Br–, I–, HSO4–, ClO4–, no
obvious changes were observed.
Crystal structure: The structure of the N-phenyl-N′-(2-
nitrobenzoyl)thiourea is shown in Fig. 1, the intramolecular
N-H···O (2.135 Å) hydrogen bonding between the amide-N
and benzoyl-O atoms completes a nearly planar six-membered
ring in the central part of the molecule. This group makes
dihedral angles of 34.98 (1) and 76.39(1)º with the o-nitrobenzoyl
and other phenyl rings, respectively.

Vol. 25, No. 16 (2013)
Crystal Structure and Properties of N-Phenyl-N'-(2-nitrobenzoyl)thiourea 9011
0.25
S
C
O
C
NO2
S
C
O
C
NO2
CH3COOH
N
H
N
H
NH
NH
0.20
F-
O
O
0.15
C
-
H
PO
4
2
CH3
Scheme-II: Proposed binding mode of L1 with OAc– in DMSO
Ac-
OAc
–
0.10
0.05
Host and other anions
Biological activity: We also investigated plant growth
regulation activity. Here, we adopted the method of plate
culture. The compound was collected to the solutions in concen-
tration of 100, 10, 1, 0.1, 0.01 and 0.001 ppm and rape seeds
were cultured in a 10 cm petri-dish with 10 mL different
solutions and a circular filter paper. After growing at room
temperature for 4 days, the root length was gained and the
percentage plant growth activity was calculated according to
the following equation:
0.00
300
350
400
450
Wavelength (nm)
Wavelength/nm
Fig. 3. UV-visible absorption of sensor L1 (c = 2.0 × 10-5 M) in the presence
of 50 equiv. various anions in DMSO
UV-visible titrations were carried out in DMSO at a
concentration of 2.0 × 10-5 mol L-1 with the addition of tetrabutyl-
ammonium OAc–, the spectra are shown in (Fig. 4). The plot
gives a 1:1 stoichiometric ratio between OAc– and L1 in
(Fig. 5), by the association constants Ka of the sensor10 L1
toward OAc– was obtained as 1.5 × 105 M-1.
(N − N1)
Percentage plant growth activity =
×100 %
N1
In the equation, N is the root length cultured in compound
solutions and N1 is the root length cultured in the distilled
water under the same condition. The data are shown in
Table-4.
0.4
0.2
0.0
TABLE-4
PLANT GROWTH REGULATING ACTIVITY DATA (RAPE)
Plant growth activity (%)a
Compound
100
10
1
0.1
0.01
ppm
0.001
ppm
ppm
ppm
ppm
ppm
L1
-100
-100
-22.1
-92.5
67.4
-91.2
68.2
-80.2
49.6
-28.9
16.3
-10.7
Heteroauxing
aSolution was prepared in the proportion of H2O:DMF = 99.5:0.5 and
0.1 g Tween-80 was added to promote the compound to dissolved.
300
350
400
Wavelength (nm)
Wavelength/nm
From the results summarized in Table-4, compared with
heteroauxing, the compound exhibited root elongation activity
and with the concentration was decreased from 100-0.001 ppm,
the root elongation activity becomes strengthener gradually.
It was obvious that the compound shown excellent plant-
growth regulation activity in the concentration of 0.1 ppm,
which the growth activity was reached to 68.2 %.
Fig. 4. UV-visible spectral titration of sensor L1 with OAc–
0.10
0.08
0.06
0.04
0.02
0.00
Conclusion
In summary, we have synthesized N-phenyl-N′-(2-
nitrobenzoyl)thiourea in high yield. The crystal structure show
that the intramolecular N-H···O hydrogen bonding between
the amide-N and benzoyl-O atoms completes a nearly planar
six-membered ring in the central part of the molecule, more-
over, in the crystals, the moleculars of L1 were linked to one-
dimensional chain-like superamolecular through the inter-
molecular hydrogen bonds. The anion-binding properties of
L1 has been studied by UV-visible, which is shown to be
capable of strongly binding for OAc- through hydrogen
bonding interaction in DMSO and formed a 1:1 stoichiometry
complex. In addition, investigation of biological activity shows
the compound show good plant-growth regulation activity.
0.000
0.005
0.010
0.015
Ac-/–LI
0.020
0.025
0.030
OAc /L1
Fig. 5. Plot of the absorbance at 303 nm vs. equivalents of OAc– in DMSO.
C (L1) = 2 × 10-5 M, the correlation coefficient is 0.998
The whole reaction process was shown in Scheme-II. This
phenomenon may be attributed to its basicity and geometry
configuration to converge the two -NH groups at a point via
-NH- anions hydrogen binding11.

9012 Hu et al.
Asian J. Chem.
4. M.M.G. Antonisse and D.N. Reinhoudt, Chem. Commun., 443 (1998).
5. T.S. Snowden and E.V. Anslyn, Curr. Opin. Chem. Biol., 3, 740 (1999).
6. D.A. Jose, D.K. Kumar, B. Ganguly and A. Das, Org. Lett., 6, 3445
(2004).
7. L.S. Evans, P.A. Gale, M.E. Light and R. Quesada, Chem. Commun.,
965 (2006).
ACKNOWLEDGEMENTS
The authors gratefully acknowledged the support of the
Colleges and Universities Graduate advisor research project
in Gansu Province (No. 0804-11).
8. J.H. Hu, W.X. Xu and T.B. Wei, Spectrosc. Spectr. Anal., 6, 27 (2007).
9. S. Tsuzuki, K. Honda and R. Azumi, J. Am. Chem. Soc., 124, 12200
(2002).
10. X.D. Yu, H. Lin, Z.S. Cai and H.K. Lin, Tetrahedron Lett., 48, 8615
(2007).
REFERENCES
1. S.Y. Chung, S. W. Nam, J. Lim, S. Park and J. Yoon, Chem. Commun.,
2866 (2009).
2. C.H. Park and H.E. Simmons, J. Am. Chem. Soc., 90, 2431 (1968).
3. F.P. Schmidtchen and M. Berger, Chem. Rev., 97, 1609 (1997).
11. J. Shao, H. Lin and H.K. Lin, Dyes Pigments, 80, 259 (2009).