Antibacterial studies of copper(I) complexes with benzoylthiourea derivatives

Article abstract of DOI:10.14233/ajchem.2013.15167

Four copper(I) complexes of bisbenzoylthiourea derivatives have been synthesized and characterized by elemental analyses as well as IR spectroscopy and TG-DTA analyses. Antibacterial activity assay exhibited MIC₅₀ values of these compounds comp

Full text of DOI:10.14233/ajchem.2013.15167

Asian Journal of Chemistry; Vol. 25, No. 14 (2013), 8102-8104
http://dx.doi.org/10.14233/ajchem.2013.15167
Antibacterial Studies of Copper(I) Complexes with Benzoylthiourea Derivatives
*
MENG-MENG ZHAO , XIU-YAN DONG, YU-HUA YANG, GANG LI, YU-JIE ZHANG and XIAO-QIN YANG
School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, P.R. China
*Corresponding author: E-mail: zhaomm80@163.com
(
Received: 17 January 2013;
Accepted: 3 August 2013)
AJC-13882
Four copper(I) complexes of bisbenzoylthiourea derivatives have been synthesized and characterized by elemental analyses as well as IR
spectroscopy and TG-DTA analyses. Antibacterial activity assay exhibited MIC50 values of these compounds comparable to standard
drugs for both gram-positive and gram-negative bacteria, some of them showed great antibacterial activity.
Key Words: Benzoylthiourea, Copper(I) complex, Synthesis, Antibacterial activity.
purchased and used without further purification. The other
reagents and solvents were analytical grade reagents from
Tianjin Chemical Reagent Factory. Elemental analyses for Cu
was detected by an IRIS ER/S·WP-1 ICP atomic emission
spectrometer. C, H and N analyses were carried out with a
GmbH VariuoEL V3.00 automatic elemental analyzer. IR
INTRODUCTION
Thiourea compounds are excellent agents of bioactive
substances. A number of biological activities are associated
1,2
with substituted thiourea derivatives . Complexes of thiourea
3
-6
derivatives have also been reported in several papers and
these compounds have been widely used in organic synthesis,
such as in the metal-catalyzed asymmetric reduction of
carbonyl compounds and carbonylative cyclization of o-
-1
spectra in the range 4000-400 cm were recorded on a VER-
1
TEX70 FT-IR spectrophotometer using KBr pellets. The H
7,8
NMR spectra were recorded on a Mercury-400BB spectrometer
hydroxyarylacetylenes . Of all the thiourea derivatives, the
N-substituted N'-acylthiourea compounds have received the
most attention, because the existence of acyl and thiocarbonyl
groups in these complexes enhances the coordination ability
of the ligands, which readily form supramolecular structures
at room temperature using CDCl as solvent. Melting points
3
was measured by the use of a microscopic melting point
apparatus made in Beijing Taike Instrument Limited Company
and the thermometer was uncorrected. The microbiology stains
were obtained from China Center of Industrial Culture Collec-
tion, including 4 species of gram-negative bacteria (Salmonella
typhimurium CCTCCM91098, Escherichia coli ACCC11864,
Pseudomonas aeruginosa NKCCMRNK10.PAO1∆rhlI and
Shigella flexneri CICC21534) and two gram-positive bacteria
9
-12
via hydrogen bonds . In many syntheses of copper comp-
1,2
lexes, irreversible Cu(II)/Cu(I) systems have been observed
and there are many reports of the reduction of Cu(II) in the
13-15
presence of thione derivatives . For the synthesis of the title
compound, the cuprous complex was obtained by the redox
reaction of cupric ions with the thiourea ligand. The reducing
agent in this reaction is the thiourea ligand, viz., N-benzoyl-
N'-(3-pyridyl)thiourea or N-(o-chloro)benzoyl-N'-(3-
(
Staphylococcus aureus ACCC01331 and Mycobacterium
tuberculosis CVCC343), Streptomycin and Ampicillin were
served as standard antibacterial agents, respectively. The
absorbance was measured using Synergy HT BioTekR USA
microplate reader.
General procedure: Benzoyl chloride or 2-chlorobenzoyl
chloride was treated with ammonium thiocyanate under the
condition of solid-liquid phase transfer catalysis using PEG-
1
3
pyridyl)thiourea, according to previous publications . This
9,16-18
reaction is similar to those reported
. Herein, four copper(I)
complexes of benzoylthiourea derivatives have been synthe-
sized and characterized by elemental analyses, IR and H NMR
spectroscopy. In the present studies, several new complexes
have been synthesized to evaluate its bioactivities. The anti-
bacterial activities are also reported.
1
4
00 as the catalyst to give the corresponding benzoyl
isothiocyanates, without isolation, the obtained benzoyl
isothiocyanates was treated with 3-pyridine to afford the
1
2
19,20
EXPERIMENTAL
ligands L -L in good-to-excellent yield . Synthetic route
1
2
Benzoyl chloride, o-chlorobenzoyl chloride, 1,2-dibromo-
ethane, 1,3-dibromopropane and polyethylene glycol-400 were
to benzoylthiourea ligands L -L is shown in Fig. 1. All the
synthesized complexes have been characterized by elemental

Vol. 25, No. 14 (2013)
Antibacterial Studies of Copper(I) Complexes with Benzoylthiourea Derivatives 8103
analyses as well as IR spectroscopy and TG-DTA analyses
for 2 h, the mixture was fltered, washed successively with hot
methanol and diethyl ether, respectively, the product was dried
under reduced pressure to obtain yellow crystalline solid.
Synthesis of copper(I) complexes of benzoylthiourea
2
1,22
(
Tables 1 and 2)
.
O
O
NH
4
SCN
Cl2 , r.t.
O
RNH
2
/CH
2 2
Cl
2
2
PEG-400/CH
2
NR
S
L : To an acetone solution (6 mL) of the ligand L (0.07294 g,
0.00025 mol) was added an methanol solution (2 mL) of cupric
r.t.
Cl
N=C=S
HN
R1
R1
R1
chloride (0.0875 g, 0.0003 mol) (or Cu(CH
3
COO)
2
·H O
2
1
1
L : R =H, R=3-pyridine;
(0.0599 g, 0.0003 mol)), a yellow-green pricipatate was formed
2
1
L : R =2-Cl, R=3-pyridine;
Fig. 1. Synthetic route to benzoylthiourea ligands L -L
immediately. After stirring for 4 h, the mixture was fltered,
washed successively with hot methanol and diethyl ether,
respectively, the product was dried under reduced pressure to
obtain green crystalline solid.
1
2
1
Synthesis of N-benzoyl-N'-(3-pyridyl)thiourea (L ):
4
.41 g (0.01 mol) of benzoyl chloride was reacted with 1.15 g
Cl
under solid-liquid phase transfer catalysis conditions, using
.19 g of 3 % polyethylene glycol-400 as the catalyst, to give
The IR spectrum of the complexes show two bands at ca.
115 and 3436 cm , due to NH stretchings. Because C=O
(
0.015 mol) of ammonium thiocyanate in 15 mL of CH
2
2
-1
3
groups are locked into the hydrogen bonds, the carbonyl
0
-1
stretching bands appears at ca. 1676 cm . A strong band at
the corresponding benzoyl isothiocyanate, which was reacted
with 0.85 g (0.01 mol) of 3-aminopyridine to give the title
compound. The solid isolated was separated from the liquid
phase by filtration, washed successively with CH
respectively, the product was dried under reduced pressure
and purified with recrystallization from chloroform to obtain
-1
ca. 1165 cm is assigned as the thionyl group, which has a red
-1
-1
2
shift of 12 cm compared with 1176 cm in free thiourea L .
This indicates coordination of the thionyl group with Cu(I).
2
Cl
2
2
and H O,
-1
In the range below 1000 cm , two peaks at ca. 590 and 406
cm are attributed to Cu-S and Cu-Cl vibrations
-1
23,24
.
Antimicrobial activity: Antibacterial activity was perfor-
1
white crystalline solid L .Yield: 61.8 %. m.p. 431-432 K.Anal.
med in sterile 96-wells microplates under aseptic environ-
calcd. (%) for C13
H
11
N
3
OS: C, 60.68; H, 4.31; N, 16.33. Found
%): C, 60.73; H, 4.23; N, 16.05.
Synthesis of N-(o-chloro)benzoyl-N'-(3-pyridyl)thiourea
25
ments . The method is based on the principle that microbial
(
cell number increases as the microbial growth proceeds in the
log phase of growth which results in increased absorbance of
broth medium. The organisms were maintained on stock culture
agar. The test samples with suitable solvent and dilution were
pipetted into wells (20 µg/well). Overnight maintained fresh
bacterial cultures after suitable dilution with fresh nutrient
broth were poured into wells (180 µL). The initial absorbance
of the culture was strictly maintained between 0.12-0.19 at
2
(
L ): o-Chlorobenzoyl chloride (1.80 g, 0.01 mol) was reacted
Cl
15 mL) under solid-liguid phase transfer catalysis, using 3 %
with ammonium thiocyanate (1.14 g, 0.015 mol) in CH
(
2
2
polyethylene glycol-400 (0.18 g) as catalyst, to give the corres-
ponding benzoyl isothiocyanate, which was reacted with
3
-aminopyridine (0.86 g, 0.01 mol). The title compound 3d
precipitated immediately. The product was filtered, washed
with water and CH Cl and dried.Yield 76.6 %, m.p. 442-444
K. Anal. calcd. (%) for C13 OSCl: C, 53.52; H, 3.45; N,
4.40. Found (%): C, 53.43; H, 3.46; N, 14.39.
Synthesis of copper(I) complexes of benzoylthiourea
5
40 nm. The total volume in each well was kept to 200 µL.
2
2
The incubation was done at 37 ºC for 16-24 h with lid on the
microplate. The absorbance was measured at 540 nm, before
and after incubation and the difference was noted as an index
of bacterial growth. The percent inhibition was calculated using
the formula:
H
10
N
3
1
1
1
L : To a methanol solution (8 mL) of the ligand L (0.2574 g,
.0 mmol) was added a methanol solution (2 mL) of cupric
chloride (0.0860 g, 0.0005 mol) (or Cu(CH COO) ·H
0.0998 g, 0.0005 mol)). After the solution had been refluxed
1
(
X − Y)
3
2
2
O
Inhibition (%) =
×100
(
X
TABLE-1
COLOUR, YIELDS AND ANALYTICALDATA OF SYNTHESIZED COMPLEXES
Yield
%)
m.f.
(m.w.)
Elemental analysis (%): found (calcd.)
Complex
Colour
(
C
H
N
Cu
1
Cu( L )Cl
Yellow
Yellow
Green
Green
82.3
81.8
90.6
65.6
C H ClCuN OS (356.31)
43.58 (43.82)
38.31 (38.20)
47.13 (47.42)
43.63 (43.48)
2.90 (3.11)
2.81 (2.96)
3.59 (3.71)
2.93 (3.16)
11.45 (11.79)
10.01 (10.28)
10.86 (11.06)
10.56 (10.14)
17.56 (17.83)
15.23 (15.55)
16.52 (16.73)
15.10 (15.34)
13
11
3
2
Cu( L )Cl·H O
C H C CuN O S (408.77)
13 12 l2 3 2
C H CuN O S (379.90)
15 14 3 3
C H ClCuN O S (414.35)
15 13 3 3
2
1
Cu( L )(CH COO)
3
2
Cu( L )(CH COO)
3
TABLE-2
IR SPECTRAL DATA AND TG-DTA DATA OF SYNTHESIZED COMPLEXES
-
1
Endothermic
peak
Exothermic
peak
Residual rate found
(calcd.)(%)
Complex
IR (cm )
Finalproduct
CuO,CuS
1
Cu( L )Cl
3435, 3119 (NH); 1676 (C=O); 1167 (C=S);
61, 142
238, 340
22.6(23.4)
5
90 (Cu-S); 406 (Cu-Cl)
3443, 3115 (NH); 1690 (C=O); 1165
C=S);592 (Cu-S); 405 (Cu-Cl)
2
Cu( L )Cl·H
2
O
69, 163
296, 329
20.9(21.4)
CuO,CuS
(
1
Cu( L )(CH
3
COO)
3433,3114 (NH); 1684 (C=O); 595 (Cu-S)
3427,3117 (NH); 1674 (C=O); 590 (Cu-S)
135
159
242, 365
230, 390
22.5(23.1)
20.3(21.1)
CuO,CuS
CuO,CuS
2
Cu( L )(CH COO)
3

8
104 Zhao et al.
Asian J. Chem.
TABLE-3
ANTIBACTERIAL ACTIVITIES OF COPPER(I) COMPLEXS (MEAN±SEM, n=3)
Antibacterial activity MIC50 (µg/mL)
Compound
S. typhi
13.35±0.09
11.9±0.44
–
12.7±0.24
9.33±0.26
11.2±0.35
E. coli
P. aeruginosa
S. flexneri
M. tuberculosis
11.8±0.24
9.25±0.31
13.5±0.11
10.75±0.2
11.1±0.33
7.95±0.27
S. aureus
12.8±0.44
9.8±0.34
14.98±0.3
10.84±0.31
11.43±0.42
9.85±0.39
3a
13.15±0.3
11.12±0.21
14.77±0.55
12.1±0.35
9.18±0.31
9.41±0.27
–
–
3
b
11.1±0.45
–
10.85±0.26
–
3
c
3
d
11.61±0.24
10.12±0.2
10.26±0.41
12.1±0.3
10.56±0.35
9.74±0.15
Ampicillin
Streptomycin
–
: Indicates no activity.
4
5
.
.
R. Campo, J.J. Criado and E. Garcia, J. Inorg. Biochem., 89, 74 (2002).
S.G. Teoh, S.H. Ang and H.K. Fun, J. Organomet. Chem., 580, 17
where X is absorbance in control with bacterial culture andY
is absorbance in test sample. Results are mean of triplicate (n
(
1999).
=
3, mean ± sem). Streptomycin and Ampicilin were taken as
6
.
B.H. Abdullah and F.K. Kadir, Asian J. Chem., 23, 153 (2011)..
standard drugs. Minimum inhibitory concentration (MIC) was
measured with suitable dilutions and results were calculated
using EZF it 5 Perrella Scientific Inc. Amherst USA software
7. F. Touchard, F. Fache and M. Lemaire, Tetrahedron: Asymm., 8, 3319
1997).
(
8
9
1
.
.
Y. Nan, H. Miao and Z. Yang, Org. Lett., 2, 297 (2000).
Y.M. Zhang, L. Xian and T.B. Wei, Acta Cryst., C59, m473 (2003).
and data expressed as MIC50
.
0. Y.M. Zhang, L. Xian, T.B. Wei and K.B. Yu, J. Chem. Res., 12, 798
2003).
11. Y.M. Zhang, W.X. Xu and Y.Q. Zhou, Acta Chim. Sin., 64, 79 (2006).
2. E. Guillon, I. DeÂchamps-Olivier and J. Barbier, Polyhedron, 17, 3255
1998).
13. S. Jeannin, Y. Jeannin and G. Lavigne, Inorg. Chem., 18, 3528 (1979).
(
RESULTS AND DISCUSSION
1
A series of Cu(I) complexes of benzoylthiourea com-
(
1
2
pounds L -L have been synthesized and characterized by
elemental analyses, IR spectra and TG-DTA analyses.
In the antibacterial experiment, the statistic indicated
lowest the MIC50 value, highest is the antibacterial activity.
These compounds were active againest both gram-positive and
gram-negative bacterial. Compounds 3b possessed the lowest
MIC50 value, so it has the highest antibacterial activity. Both
compounds 3b and 3d possessed MIC50 value close to the
standard drugs streptomycin and ampicillin (Table-3). All
compounds have prominent active againest Mycobacterium
tuberculosis. The results of this study indicated that most of
the compounds synthesized above showed their biological
importance and could be applied in biological medicine
industry.
1
1
4. E.S. Raper, Coord. Chem. Rev., 61, 115 (1985).
5. P. Karagiannidis, P. Aslanidis and S. Papastefanou, Polyhedron, 9, 2833
(
1990).
1
1
6. X. Shen, T. Wen, Q. Liu, X. Huang, B. Kang, X. Wu, Z. Huang and L.
Gu, Polyhedron, 16, 2605 (1997).
7. B.Q. Su, L. Xian, H.B. Song and L. Sheng, Acta Cryst., C60, m661
(
2004).
1
1
8. K.R. Koch, Coord. Chem. Rev., 216-217, 473 (2001).
9. L.Q. Chai,Y.J. Ding, X.Q.Yang, H.B.Yan and W.K. Dong, Acta Cryst.,
E64, o1407 (2008)
2
2
0. W.K. Dong, X.Q. Yang. L.Q. Chai, Y.Q. Tian and J.H. Feng, Phosphorus,
Sulfur Silicon Rel. Elem., 183, 1181 (2008).
1. W.K. Dong,Y.X. Sun, S.J. Xing,Y. Wang and X.H. Gao, Z. Naturforsch.,
6
7b, 197 (2012).
22. W.K. Dong, J.F. Tong, Y.X. Sun, S.S. Gong and L. Li, Synth. React.
Inorg. Met.-Org. Nano-Met. Chem., 41, 155 (2011).
2
2
3. L. Xian, T.B. Wei and Y.M. Zhang, J. Coord. Chem., 57, 453 (2004).
4. U. Bierbach, T.W. Hambley and J.D. Roberts, Inorg. Chem., 35, 4865
REFERENCES
(
1996).
2
5. M. Kaspady, V.K. Narayanaswamy, M. Raju and G.K. Rao, Lett. Drug
Design Discov., 6, 21 (2009).
1
2
3
.
.
.
E. Guillon, I. DeÂchamps-Olivier and J. Barbier, Polyhedron, 17, 3255
1998).
E. Guillon, A. Mohamadou, I. DeÂchamps-Olivier and J. Barbier, Polyhedron,
5, 947 (1996).
Y.M. Zhang, T.B. Wei, L, Xian and L.M. Gao, Phosphorus, Sulfur
Silicon Rel. Elem., 179, 2007 (2004).
(
1