Synthesis and characterization of Hg(II) and Zn(II) complexes based on 3-[(4-chlorophenylamido)]propenoic acid

Article abstract of DOI:10.1134/S0036023611110027

3-[(4-Chlorophenylamido)]propenoic acid has been synthesized by reaction of maleic anhydride and 4-chloroaniline in 1:1 molar ratio in glacial acetic acid and its metal complexes have been synthesized by the reaction of 3-[(4-chlorophenylamido)]propenoic acid with HgCl₂ and [Zn(CH ₃COO)₂] ? 2H₂O in 2: 1 molar ratio, respectively. All the synthesized compounds have been characterized by the elemental analysis, IR, UV/Vis and NMR (¹H, ¹³C) spectroscopy. Conductance for the reported compounds has been recorded in ethanol and suggests the non-electro lytic nature of complexes. IR data of metal complexes shows that the ligand is bound to the metal via both carboxylate oxygen atoms and complexes exhibits 4-coordinated geometry in solid state. NMR (¹H, ¹³C) study confirms the structure of the 3-[(4-chlorophenylamido)]propenoic acid and the reported complexes.

Full text of DOI:10.1134/S0036023611110027

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2011, Vol. 56, No. 11, pp. 1752–1756. © Pleiades Publishing, Ltd., 2011.
COORDINATION COMPOUNDS
Synthesis and Characterization of Hg(II) and Zn(II) Complexes
Based on 3–[(4–Chlorophenylamido)]propenoic Acid1
M. Z. Alia, S. Alib, and S. Shahzadia
a Department of Chemistry, GC University, Faisalabad, Pakistan
b Department of Chemistry, QuaidꢀiꢀAzam University, 45320 Islamabad, Pakistan
eꢀmail: drsa54@yahoo.com (S.A); sairashahzadi@yahoo.com (S.S.)
Received November 24, 2009
Abstract—3ꢀ[(4ꢀChlorophenylamido)]propenoic acid has been synthesized by reaction of maleic anhydride
and 4ꢀchloroaniline in 1:1 molar ratio in glacial acetic acid and its metal complexes have been synthesized by
the reaction of 3ꢀ[(4ꢀchlorophenylamido)]propenoic acid with HgCl2 and [Zn(CH3COO)2] · 2H2O in 2 : 1
molar ratio, respectively. All the synthesized compounds have been characterized by the elemental analysis,
IR, UV/Vis and NMR (1H, 13C) spectroscopy. Conductance for the reported compounds has been recorded
in ethanol and suggests the nonꢀelectro lytic nature of complexes. IR data of metal complexes shows that the
ligand is bound to the metal via both carboxylate oxygen atoms and complexes exhibits 4ꢀcoordinated geomꢀ
etry in solid state. NMR (1H, 13C) study confirms the structure of the 3ꢀ[(4ꢀchlorophenylamido)]propenoic
acid and the reported complexes.
DOI: 10.1134/S0036023611110027
1
INTRODUCTION
chased from E. Merck, Germany. Acetone, methanol,
ethanol, chloroform, dichloromethane, ether, toluꢀ
ene, nꢀhexane, DMSO and benzene were purchased
from Riedelꢀde Haen and were used without any furꢀ
ther purification. Melting points were determined by
using capillary tube on an electrothermal melting
Transition metals form complexes with carboxylate
anions. A versatile carboxylate anion can adopt a wide
range of bonding modes, including monodentate,
symmetric and asymmetric chelating, and bidentate
and monodentate bridging [1, 2]. Transition metal
complexes have attracted great interest for their appliꢀ point apparatus, model Stuart (SMP3) and are uncorꢀ
cation in industrial and synthetic processes, such as
catalysis, photochemistry, and biological applications
[3]. The selfꢀassembly of organic ligands coordinated
to metal ions or organometallic substances has been
extensively studied [4]. The increasing interest in this
field is mainly due to the potential relevance of such
complexes to catalysis [5]. Coordination complexes of
transition metal had been widely studied for their antiꢀ
microbial and [6, 7] anticancer properties . One of the
most potent and [8, 9] effective antitumour agents was
discovered in the last century serendipitously by
Rosenberg [10]. Various tumor cell lines are now
growing resistance to cisplatin e.g., acquired cisplatin
resistance in some preclinical tumor models [11]. In
the present study, Zn(II) and Hg(II) complexes of 3–
[(4–chlorophenylamido)]propenoic acid were synꢀ
thesized and characterized.
rected. FTꢀIR Spectra were recorded as KBr discs on
PerkinꢀElmerꢀ1000 spectrophotometer in the range of
4000–250 cm–1. Elemental analysis was done on a
CHN analyzer 932 Leco, USA. Conductance of the
complexes was noted from 712 conductometer of
Metrohm. Ultravioletꢀvisible spectra in 800–200 nm
range were recorded on a Schimadzu TCCꢀ240 A specꢀ
1
trophotometer (AvH, Germany). H and 13C NMR
spectra were recorded on BrukerꢀAM 300 MHzꢀFTꢀ
NMR spectrometer using CDCl3 as internal reference.
Synthesis of 3ꢀ[(4ꢀChlorophenylamido)]
Propenoic Acid HL
Maleic anhydride (1 gm, 10.19 mmol) was disꢀ
solved in glacial acetic acid (10 mL) in (500 mL) beaꢀ
ker, while 4ꢀchloroaniline (1.3 gm, 10.19 mmol) was
also dissolved in glacial acetic acid (10 mL) in (500 mL)
beaker. Then mix both solutions dropwise with conꢀ
stant stirring. Continue the stirring for 3–4 hours.
Light yellow precipitates formed were filtered off and
washed with distilled water and dried in air. The prodꢀ
EXPERIMENTAL
Materials and Instrumentation
Maleic anhydride, 4ꢀchloro aniline, glacial acetic
acid, zinc acetate and mercuric chloride were purꢀ
1
The article is published in the original.
uct was crystallized in acetone :
nꢀhexane (1 : 1).
1752

SYNTHESIS AND CHARACTERIZATION OF Hg(II) AND Zn(II) COMPLEXES
1753
Table 1. Physical data of 3ꢀ[(4ꢀchlorophenylamido)]propenoic acid and its complexes
Compound No.
HL
Molecular formula
Molecular mass
% Yield
mp (°C)
C10H8O3NCl
225.5
649.5
550.28
92
80
83
204–207
180–183
155–158
(
(
1
)
)
C20H14O6N2Cl2Hg
C20H18O8N2Cl2Zn
2
Cl
Cl
NH2
Cl
O
Glacial
Acetic acid
2
+
+ Zn(CH3COO)2 ⋅ 2H2O
O
O
O
O
HN
O
HN
Cl
OH
OH
O
Cl
+ 2CH3COOH
Synthesis of Compound (1)
3ꢀ[(4ꢀchlorophenylamido)]propenoic acid (2 mmol)
O
O
Zn
HN
C
C
NH
O
O
was dissolved on heating at 40–50 in (35–40 mL)
°
C
O
O
acetone in roundꢀbottom flask (250 mL) with constant
stirring. Then the solution of HgCl2 (1 mmol) disꢀ
solved in (20–25 mL) acetone was added drop wise to
the reaction mixture and stirred it for 3 hours. Precipꢀ
itates formed were filtered and dried in air. Purity of
the product was checked by TLC.
⋅
2H2O
RESULTS AND DISCUSSION
3ꢀ[(4ꢀchlorophenylamido)]propenoic acid and its
complexes were synthesized in crystalline solid state.
They have sharp melting points and are soluble in
common organic solvents. Physical data are summaꢀ
rized in Table 1.
Cl
+ HgCl2
2
O
Elemental analysis (CHN)
HN
Cl
OH
Elemental analysis was done to compare the
observed values of percentage of the carbon, hydrogen
and nitrogen in the synthesized compounds with those
of calculated and predicted values. The observed valꢀ
ues are in very good agreement with the calculated valꢀ
ues. Elemental data are given in the Table 2.
O
Cl
+ 2HCl
O
O
O
Hg
HN
C
C
NH
Infrared Spectroscopy
O
Infrared spectra of the HL and compounds (1)–(2)
O
O
were recorded in the range 250–4000 cm–1. The comꢀ
plexation of ligand with metal is confirmed by disapꢀ
pearance of –OH band, which appears at 3370 cm–1 in
the ligand. This is characteristic of carboxylic acid.
Replacement of carboxylic group hydrogen by the
metal, brought about characteristic changes in IR
spectra of complexes in comparison with the spectra of
ligand. The difference (Δν) between νasym(COO–) and
νsym(COO–) is a parameter that identifies the type of
bonding metalꢀligand. The values of Δν are 167 and
Synthesis of Compound (2)
3ꢀ[(4ꢀchlorophenylamido)]propenoic acid (2 mmol)
was dissolved on heating at 40–50 in (35–40 mL)
°
C
mathanol in roundꢀbottom flask (250 mL) with conꢀ
stant stirring. Then the solution of zinc acetate
[Zn(CH3COO)2] 2H2O (1 mmol) dissolved in (20–
⋅
172 cm–1 for compounds (
while Δν = 235 cm–1 for ligand [12]. In addition, the
ligand and compounds ( ) and ( ), exhibit bands in
1) and (2), respectively,
25 mL) methanol was added drop wise to the reaction
solution and stirred it for three hours. Precipitates
formed were filtered and dried in air.
1
2
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 11 2011

1754
ALI et al.
Table 2. CHN analysis of 3ꢀ[(4ꢀchlorophenylamido)]propenoic acid and its complexes
Compound No.
HL
%
C
H
N
Calculated
53.20
53.16
3.54
3.59
6.20
6.16
Found
(
1
)
)
Calculated
Found
36.95
36.99
2.15
2.11
4.31
4.35
(
2
Calculated
Found
43.61
43.59
3.27
3.31
5.08
5.03
Table 3. IR data (cm–1) of 3ꢀ[(4ꢀchlorophenylamido)]propenoic acid and its complexes
ν
COO
ν
COO
sym
Comp. No.
HL
ν
OH
ν
H2O
ν
NH
ν
C=O
Δν
ν
M–C
ν
M–O
asym
3370
–
–
–
3273
3276
3274
1702
1701
1706
1628
1485
1489
1393
1318
1317
235
167
172
–
–
(1
)
)
508
504
442
440
(2
–
3480
Table 4. Conductance of 3ꢀ[(4ꢀchlorophenylamido)]proꢀ
penoic acid and its complexes
nonꢀelectrolytic nature of complexes. Data is given in
Table 4.
Comp. No.
HL
Conductance μs/cm
UVꢀVisible Spectroscopy
0.40
16.14
36.46
The UVꢀvisible spectral data of 3ꢀ[(4ꢀchloropheꢀ
nyIamido)]propenoic acid and its complexes recorded
in methanol are given in Table 5. Absorption of the
3ꢀ[(4ꢀchlorophenylamido)]propenoic acid in the
(
1
)
)
(2
region 38214 cm–1 is due to the
The absorption spectra of complexes (
n
π
*
transition.
Table 5. UV/Vis data of 3ꢀ[(4ꢀchlorophenylamido)]propeꢀ
noic acid and its complexes
1
) and ( ) are
2
transparent in the visible part of the spectrum,
because both these metal ions have completely filled
orbitals and have no bands due to d–d transitions.
Comp. No.
HL
ν
(cm–1)
Assigned transition
* transition
d
38214
41896
44642
n
π
However, the presence of highꢀintensity bands at
41896 and 44642 cm–1 in the spectra of the complexes
(
1
)
)
Charge transfer band
Charge transfer band
(1) and (2) is indicative of the presence of the ligand
and thus the formation of the complexes.
(2
the range of 3273–3276 cm–1 due to the
(NH) group.
ν
NMR Spectroscopy 1H NMR
The amide group in all the complexes is not affected
and remains unchanged, strongly indicating nonꢀ
involvement in complex formation. The appearance of
bands at 440–442 cm–1 (M–O) confirms the bonding
of oxygen atoms of ligand to the metal atom [13]. IR
spectral data is given in Table 3.
Three distinct informations are generally obtained
from this technique. The chemical shift of peak gives
information about the environment of proton
involved, the intensity of each peak corresponds to
number of protons and multiplicity tells about the
number of neighbouring protons.
The signals in 1H NMR spectra are sharp and wellꢀ
resolved. From the 1H NMR spectra of HL it showed the
broad multiplet in the range 7.33–7.68 ppm for the C6H4
Conductance
The molar conductance values of the synthesized protons [14]. The resonance signal at the range 6.30–
complexes (1)–(2) determined in ethanol (concentraꢀ 6.51 ppm represents the unsaturated group with the
tion = 0.001 M) at room temperature, suggests the nJ(1H, 1H) coupling 8.0 Hz, and a singlet at 13.13 ppm
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 11 2011

SYNTHESIS AND CHARACTERIZATION OF Hg(II) AND Zn(II) COMPLEXES
1755
Table 6. 1H NMR data (ppm) of 3ꢀ[(4ꢀchlorophenylamido)]propenoic acida and its complexes
Proton No.
HL
(1)
(2)
7.33–7.68 m
7.36–7.77
7.31–7.72 m
Cl
–NH
10.51 s
10.51 s
6.32–6.37 d,d (8.0)
6.30–6.34 d,d (8.0)
–
10.51 s
6.49–6.55 d,d (8.0)
6.45–6.57 d,d (8.0)
–
–CH=CH–
6.30–6.34 d,d (8.0)
6.47–6.51 d,d (8.0)
13.13 s
–OH
a
Note:
⎯Multiplicity is given as s; singlet, d,d; doublet of doublet, m; multiplet.
confirms the carboxylic proton resonance, while the olefinic carbon atom and the signal at 167.34 ppm conꢀ
disappearance of OH signal in complexes ( ) and ( firms the carboxylic carbon atom. The carboxylic carꢀ
confirms the complex formation. The 1H NMR data is bon shows downfield shift in the range of 170.12–
1
2)
presented in Table 6.
170.44 in the complexes (1) and (2) thus confirming the
complexation. The 13C NMR data is given in Table 7.
13C NMR
CONCLUSIONS
13C NMR spectroscopy gives direct information
about its carbon skeleton because its spectrum displays
signals arising from all the carbon atoms present in the
3ꢀ[(4ꢀchlorophenylamido)]propenoic acid and its
metal complexes have been synthesized in quantitative
yield, under stirring condition. The ligand HL and the
synthesized compounds have been characterized by
the elemental analysis, IR and NMR (1H, 13C) specꢀ
troscopy. Elemental analysis data shows the good
agreement between calculated and found values of
carbon, hydrogen and nitrogen. IR data of the comꢀ
plexes shows that ligand act as bidentate and comꢀ
13
molecule. The C NMR spectrum of compound HL
shows a signal at 163.87 ppm for the C=O carbon. The
signals at 137.93, 132.19, 130.81 and 129.13 ppm are
for the aromatic carbons. The number of the signals
found corresponds with the presence of magnetically
nonꢀequivalent carbon atom, which was assigned by
comparison with literature values [14]. The signals in
the range 121.51–128.01 ppm, revealing the presence of
plexes (1)–(2) exhibits 4ꢀcoordinated geometry in
solid state and conductance data suggests the nonꢀ
electrolytic nature of complexes. UV/Vis spectral data
Table 7. 13C NMR data (ppm) of 3ꢀ[(4ꢀchlorophenylaꢀ shows the transitions above 4000 cm–1, which can be
mido)]propenoic acida and its complexes
assigned as charge transfer band. (1H, 13C) data of HL
and complexes ( )–( ) confirms the structure of 3ꢀ
1
2
13C No.
HL
(
1)
(2)
[(4ꢀchlorophenylamido)]propenoic acid and comꢀ
plexes.
1
2,2'
3,3'
4
137.93
132.19
130.81
129.13
163.87
128.01
121.50
167.34
137.90
132.16
130.82
129.13
163.80
128.01
121.54
170.12
137.91
132.18
130.84
129.13
163.84
128.02
121.57
170.44
ACKNOWLEDGMENTS
SA an SS are thankful to QuaidꢀiꢀAzam University,
Islamabad and GC University, Faisalabad.
5
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