Studies on the crystal structure and properties of N-(2-ethoxyphenyl)- N′-(4-ethoxybenzoyl)-thiourea

Article abstract of DOI:10.1080/10426500701693495

The N-(2-ethoxyphenyl)-N′-(4-ethoxybenzoyl)-thiourea has been synthesized under phase transfer catalysis at room temperature. The compound was characterized via IR, 1H NMR, 13C NMR, elemental analysis, and the structure of the compound was determined by X

Full text of DOI:10.1080/10426500701693495

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Studies on the Crystal
Structure and Properties of
N-(2-ethoxyphenyl)-N′-(4-
ethoxybenzoyl)-thiourea
Jing-Han Hu a , Li Xu a , Jun Wang b & Tai-Bao Wei b
a College of Chemical and Biological Engineering ,
Lanzhou Jiaotong University , Lanzhou, Gansu, P. R.
China
b Department of Chemistry , Northwest Normal
University , Lanzhou, Gansu, P.R. China
Published online: 24 Jun 2008.
To cite this article: Jing-Han Hu , Li Xu , Jun Wang & Tai-Bao Wei (2008) Studies on
the Crystal Structure and Properties of N-(2-ethoxyphenyl)-N′-(4-ethoxybenzoyl)-
thiourea, Phosphorus, Sulfur, and Silicon and the Related Elements, 183:7, 1584-1591,
DOI: 10.1080/10426500701693495
To link to this article: http://dx.doi.org/10.1080/10426500701693495
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Phosphorus, Sulfur, and Silicon, 183:1584–1591, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500701693495
Studies on the Crystal Structure and Properties
of N-(2-ethoxyphenyl)-N’-(4-ethoxybenzoyl)-thiourea
Jing-Han Hu,1 Li Xu,1 Jun Wang,2 and Tai-Bao Wei2
1College of Chemical and Biological Engineering, Lanzhou Jiaotong
University, Lanzhou, Gansu, P. R. China
2Department of Chemistry, Northwest Normal University, Lanzhou,
Gansu, P.R. China
The N-(2-ethoxyphenyl)-Nꢀ-(4-ethoxybenzoyl)-thiourea has been synthesized under
phase transfer catalysis at room temperature. The compound was characterized
1
13
via IR, H NMR, C NMR, elemental analysis, and the structure of the compound
was determined by X-ray diffraction analysis. Its crystal belongs to nonoclinic space
group, with a = 2.0236(5) nm, b = 1.4543(4) nm, c = 1.4067(3) nm and α = 90.00◦,
β = 119.21(1)◦, γ = 90.00◦ and Z = 8. The compound exhibits selective recogni-
tion for H PO−, AcO−, and F− in Me SO. In addition, the compound is also a
2
2
4
considerable plant-growth regulator.
Keywords Anion recognition property; biological activity; crystal structure; thiourea
INTRODUCTION
Studies of N-aryl-Nꢀ-benzoyl-thiourea have attracted increasingly con-
siderable attention due to their potential use in agriculture, extraction,
separation, medicine and analytical chemistry.1−4 And N-acyl-thiourea
derivatives are associated with various kinds of biological activities.5
The crystal structures of those compounds have revealed many signif-
icant structural phenomena, including inter-, intra-molecular hydro-
gen bonds, and π − π interactions between phenyl groups. Recently,
thiourea and its derivatives as neutral receptors have been growing in
the field of host-guest chemistry.6−8 Among a variety of possible H-bond
donor groups, systems employing thiourea moieties have been proven
Received 5 May 2007; accepted 27 August 2007.
We gratefully acknowledge the support of the Key Project of Gansu Provincial Sci-
ence and Technological Department (No. 2GS057-A52-001-04), National Natural Science
Foundation of China (No. 20671077).
Address correspondence to Jing-Han Hu, College of Chemical and Biological Engi-
neering, Lanzhou Jiaotong University, Lanzhou, Gansu, 730070, P. R. China. E-mail:
hujinghan62@163.com
1584

Crystal Structure of an Ethoxybenzoyl Thiourea
1585
to be very efficient in the design of neutral anion binding receptors.9−13
Moreover, it is well demonstrated that phenyl substituted thiourea com-
pounds exhibit strong binding ability13 as compared with that of alkyl
substituted ones. In continuation of our earlier work,14 we report the
preparation of the title compound and study its properties. The results
show that it can be used as anion sensor in DMSO, owing to its ability
to act as classical H-bond donor. At the same time, by investigating the
biological activity of the title compound, we found that the compound
has high plant growth regulating activity at low concentration.
RESULTS AND DISCUSSION
N-(2-ethoxyphenyl)-Nꢀ-(4-ethoxybenzoyl)-thiourea has been synthe-
sized according to the previous papers15−16 in high yield under PEG-400
as the phase-transfer catalyst (Scheme 1). And, it was characterized
1
by element analysis, IR, H NMR, 13C NMR, and X-ray single crystal
diffraction.
O
N
O
PEG-400
CH2Cl2/r.t.
+
O
O
KSCN
C
S
Cl
1
2
NH2
O
S
N
H
N
H
O
O
O
CH2Cl2/r.t.
3
SCHEME 1
Structure Determination
Intensity data of title compound was collected 296(2) K on the Bruker
SMART diffractometer and used graphite monochromatic MoKα ra-
˚
diation (λ = 0.71073 A). A total of 3365 unique reflections (R(int) =
0.0197) were collected in the range of 1.81◦ < θ < 25.50◦ (0 ≤ h ≤ 24, 1
≤ k ≤ 17, −17 ≤ l ≤ 14) with ꢀ-ω scans mode, in which 1572 reflections
are l < 2σ(I). Empirical absorption correction was applied to the raw
intensities by using SADABS program.17 The structure was solved by
direct methods and full-matrix least-squares method based on F2 using
SHELXTL program package.18 Non-hydrogen atoms were subjected to
anisotropic refinement. The data collection and refinement processes
for C18H20N2O3S are summarized in Table I.

1586
J.-H. Hu et al.
TABLE I The Crystal Data of the Title Compound
Empirical formula
Formula weight
Crystal system
Space group
C18H20N2O3S
344.43
Monoclinic
C2/c
Unit cell dimensions
a = 2.0236(5) nm α = 90.00◦
b = 1.4543(4) nm β = 119.21(1)◦
c = 1.4067(3) nm γ = 90.00◦
3.6135(19) nm−3
8
Volume
Z
Density (calculated)
Absorption correction
F(000)
Absorption coefficient
Reflections collected
Independent reflections
Data/restraints/parameters
Final R indices [I > 2sigma(I)]
R indices (all data)
Goodness of fit on F2
Largest diff. Peak and hole
1.274 mg/cm3
empirical
1465
0.198 mm−1
3365
1572 [R(int) = 0.0197]
3365 /0 / 231
R1 = 0.0437, wR2 = 0.0827
R1 = 0.1061, wR2 = 0.0918
0.974
0.196 and −0.181 e. A
−3
˚
Crystal Structure
The structure of the title compound is shown in Figure 1. Selected bond
distances and angles are listed in Table II. As presented in Figure 1, the
N1-H pendant arm extends towards the carbonyl O atom and forms an
intramolecular hydrogen bond between them (Table III). The six atoms
N(1)-C(7)-N(2)-C(8)-O(2) in the hydrogen-bonded ring structure are al-
˚
most coplanar, the mean deviation from plane is 0.0253A. And, this six-
membered ring forms a dihedral angle of 13◦ and 152.9◦ with the plane
O(2), C(8), C(9), C(14), and C(6), C(7), N(1), C(1), O(1), respectively.
FIGURE 1 The crystal structure of the title compound.

Crystal Structure of an Ethoxybenzoyl Thiourea
1587
TABLE II Selected Bond Distances (nm) and
Bond Angles (◦) for the Compound
Bond lengths
S-C(7)
O(1)-C(17)
O(3)-C(12)
N(1)-C(7)
N(2)-C(7)
C(1)-C(6)
1.658(2)
1.415(3)
1.359(3)
1.337(3)
1.379(3)
1.389(3)
O(1)- C(1)
O(2)-C(8)
O(3)-C(15)
N(1)-C(6)
N(2)-C(8)
C(1)-C(2)
1.365(3)
1.217(2)
1.423(3)
1.421(3)
1.384(2)
1.407(4)
Bond angles
C(1)-O(1)-C(17)
O(2)-C(8)-N(2)
O(2)-C(8)-C(9)
O(1)-C(1)-C(6)
C(6)-C(1)-C(2)
C(4)-C(3)-C(2)
118.5(3)
120.5(2)
122.9(2)
115.3(3)
120.5(3)
122.8(4)
C(7)-N(1)-C(6)
C(12)-O(3)-C(15)
C(7)-N(2)-C(8)
O(1)-C(1)-C(2)
C(3)-C(2)-C(1)
C(3)-C(4)-C(5)
130.5(2)
118.7(2)
130.1(2)
124.2(3)
117.3(4)
120.0(4)
From Figure 2, in the crystal structure ,we can see that each pair of
. . .
molecules is connected with a dimer by two intermolecular N H
hydrogen bonds (Figure 3).
S
Anion Recognition Properties
The binding ability of receptor 3 towards different anions (tetra(n-butyl)
ammonium were used for counter cations) was investigated through
UV-Vis titration experiment in DMSO. Data from UV-Vis titrations
were processed through a non-linear least-squares procedure19 in or-
der to determine association constants K. The result indicated that−the
receptor 3 exhibited selective recognition for F−, AcO−, and H2PO in
DMSO. However, the addition of other anions scarcely showed spec4tral
changes.
Upon addition of AcO− from 0 to 200 equiv., the peak at 298 nm
decreases while a new peak of 325 nm increases and appears two
isosbestic points, which suggested the formation of complex between
receptor 3 and AcO−, as shown in Figure 4. The association constant
and correlation coefficient of receptor 3 with AcO− were 1.1 104, 0.9965,
TABLE III Data of Hydrogen Bond(nm) and Angle (◦) of Title
Compound
D—H· · ·A
D—H
H· · ·A
0.191
D· · ·A
DHA
Symmetry code
N(1)-H(1)· · ·O(2)
N(2)-H(2)· · ·N
0.086
0.086(2)
0.2628(2)
0.3514(1)
139.80(1)
152.90(19)
0.2730(1)
x
+1/2, y+1/2,Z

1588
J.-H. Hu et al.
FIGURE 2 A view of the intermolecular hydrogen bonds N H· · ·S.
respectively. The results illustrated the 1:1 stoichiometry complex was
formed by hydrogen bonding, as show in Figure 5. The anion-binding
properties of F− and H2PO− in DMSO are similar to it of AcO−, the
4
association constant were 2.7 × 104, 1.0 × 103, respectively. These
results demonstrate that receptor 3 can be used for sensing F− and
AcO− over H2PO−.
4
Biological Activity
We also investigated plant growth regulation activity. Here, we adopted
the method of plate culture. The compound was collected to the solution
FIGURE 3 Packing diagram of the title compound.

Crystal Structure of an Ethoxybenzoyl Thiourea
1589
FIGURE 4 UV-vis spectra of 3 (2 × 10−5) in DMSO after the addition of 0→200
equiv. of AcO−.
in concentration of 100 ppm, 50 ppm, 10 ppm, and coleseed was cultured
in a 10 cm Petri dish with 10 mL different solution 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:
Percentage plant growth activity = (N N1)/N1 × 100%
(1)
In Eq. (1), N is the root length cultured in compound solution and
N1 is the root length cultured in the distilled water under the same
condition. The data are shown in Table IV.
From the results summarized in Table IV, compared with heteroaux-
ing, the compound exhibited root elongation activity, and with the
FIGURE 5 Plot of the absorbance of receptor 3 at 298 nm vs. equivalents of
AcO− in DMSO.

1590
J.-H. Hu et al.
TABLE IV Plant Growth Regulating Activity Data (Rape)
% Plant growth activity a
Compound
100 ppm
50 ppm
10 ppm
3
20.15
−81.7
31.55
−63.1
37.76
−30.9
Heteroauxing
aThe solution 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.
concentration was decreased from 100 ppm to 10 ppm, the root elon-
gation activity becomes strengthener gradually. It is evident that the
compound show good plant-growth regulation activity.
CONCLUSIONS
In summary, we have synthesized N-(2-ethoxyphenyl)-Nꢀ-(4-ethoxy-
1
benzoyl)- thiourea based anion receptor and determined IR, H NMR,
13C NMR, and X-ray diffraction analysis. The compound crystallizes in
nonoclinic space group and each pair of molecules is connected with
. . .
a dimer by two intermolecular N H S hydrogen bonds. The anion-
binding properties have been studied by UV-Vis, which is shown to be
capable of strongly binding for F− and AcO− over H2PO− through hy-
drogen bonding interaction in DMSO and formed a 1:1 4stoichiometry
complex with basic anions. In addition, investigation of biological ac-
tivity shows the compound show good plant-growth regulation activity.
EXPERIMENTAL
Material and Methods
Melting points were measured on a X-4 digital melting-point apparatus
and were uncorrected. The infrared spectra were performed on a Digilab
FTS-3000 FT-IR spectrophotometer. 1H NMR and 13C NMR spectra
were recorded on a Varian Mercury plus-400 MHz spectrometer.
General Procedure for the Preparation of Compounds 3
Powdered potassium thiocyanate 0.73 g (7.5 mmol) 4-ethoxybenzoyl
chloride 0.92 g (5 mmol), PEG-400 (3% With respect to ammonium
thiocyanate), and 20 mL of dichloromethane were placed in a dried
round-bottomed flask containing a magnetic stirrer bar and stirred at
room temperature for 1 h; then 2-ethoxybenzenamine 0.69 g (5 mmol)

Crystal Structure of an Ethoxybenzoyl Thiourea
1591
was added, and the mixture was stirred for additional 0.5 h. The cor-
responding thiosemicarbazide precipitates immediately. The product is
filtered, washed with water to remove inorganic salts, dried, and re-
crystallized from DMF-EtOH-H2O to give the title compound.
1
Yield, 78%; m.p. 119–121◦C; H NMR(DMSO-d6, 400MHz) δ: 13.27
(s, 1H, NH), 11.34(s, H, NH), 6.99 ∼8.76(m, 8H, ArH), 4.11(dd 2H,
CH2), 4.15(dd 2H, CH2), 1.35(t, 3H, CH3), 1.42 (t, 3H, CH3); 13C NMR
(DMSO-d6, 400MHz) δ: 14.50, 14.59, 63.61, 64.33, 112.26, 114.12(2C),
119.72, 122.47, 123.64, 126.30, 127.35, 131.02(2C), 149.59, 162.52,
167.54, 177.63; IR (KBr, cm−1)υ: 3307, 3039 (NH), 2977, 2931 (CH),
1602, 1549, 1499 (Ar), 1675 (C O), 1155 (C S); 1249(-O-); Anal. calcd.
for C18H20N2SO3: C: 62.77, H: 5.85, N: 8.13; found C: 62.70, H: 5.90, N:
8.07.
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