Synthesis, spectroscopic and thermal characterization of sulpiride complexes of iron, manganese, copper, cobalt, nickel, and zinc salts. Antibacterial and antifungal activity

Article abstract of DOI:10.1016/j.saa.2010.03.016

Sulpiride (SPR; L) is a substituted benzamide antipsychotic which is reported to be a selective antagonist of central dopamine receptors and claimed to have mood-elevating properties. The ligation behaviour of SPR drug is studied in order to give an idea about its potentiality towards some transition metals in vitro systems. Metal complexes of SPR have been synthesized by reaction with different metal chlorides. The metal complexes of SPR with the formula [MCl₂(L)₂(H₂O)₂]·nH₂O [M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); n = 0-2] and [FeCl₂(HL)(H₂O)₃]Cl·H₂O have been synthesized and characterized using elemental analysis (CHN), electronic (infrared, solid reflectance and ¹H NMR spectra) and thermal analyses (TG and DTA). The molar conductance data reveal that the bivalent metal chelates are non-electrolytes while Fe(III) complex is 1:1 electrolyte. IR spectra show that SPR is coordinated to the metal ions in a neutral monodentate manner with the amide O. From the magnetic and solid reflectance spectra, octahedral geometry is suggested. The thermal decomposition processes of these complexes were discussed. The correlation coefficient, the activation energies, E*, the pre-exponential factor, A, and the entropies, ΔS*, enthalpies, ΔH*, Gibbs free energies, ΔG*, of the thermal decomposition reactions have been derived from thermogravimetric (TG) and differential thermogravimetric (DTG) curves. The synthesized ligand and its metal complexes were also screened for their antibacterial and antifungal activity against bacterial species (Escherichia coli and Staphylococcus aureus) and fungi (Aspergillus flavus and Candida albicans). The activity data show that the metal complexes are found to have antibacterial and antifungal activity than the parent drug and less than the standard.

Full text of DOI:10.1016/j.saa.2010.03.016

Spectrochimica Acta Part A 76 (2010) 341–347
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Synthesis, spectroscopic and thermal characterization of sulpiride complexes
of iron, manganese, copper, cobalt, nickel, and zinc salts. Antibacterial
and antifungal activity
Gehad G. Mohameda,∗, Madiha H. Solimanb
a Department of Chemistry, Faculty of Science, Cairo University, 12613, Giza, Egypt
b Department of Chemistry, Faculty of Science, Helwan University, Helwan, Egypt
a r t i c l e i n f o
a b s t r a c t
Article history:
Sulpiride (SPR; L) is a substituted benzamide antipsychotic which is reported to be a selective antagonist
of central dopamine receptors and claimed to have mood-elevating properties. The ligation behaviour
of SPR drug is studied in order to give an idea about its potentiality towards some transition metals in
vitro systems. Metal complexes of SPR have been synthesized by reaction with different metal chlorides.
The metal complexes of SPR with the formula [MCl2(L)2(H2O)2]·nH2O [M = Mn(II), Co(II), Ni(II), Cu(II) and
Zn(II); n = 0–2] and [FeCl2(HL)(H2O)3]Cl·H2O have been synthesized and characterized using elemental
analysis (CHN), electronic (infrared, solid reflectance and 1H NMR spectra) and thermal analyses (TG and
DTA). The molar conductance data reveal that the bivalent metal chelates are non-electrolytes while
Fe(III) complex is 1:1 electrolyte. IR spectra show that SPR is coordinated to the metal ions in a neutral
monodentate manner with the amide O. From the magnetic and solid reflectance spectra, octahedral
geometry is suggested. The thermal decomposition processes of these complexes were discussed. The
correlation coefficient, the activation energies, E*, the pre-exponential factor, A, and the entropies, ꢀS*,
enthalpies, ꢀH*, Gibbs free energies, ꢀG*, of the thermal decomposition reactions have been derived
from thermogravimetric (TG) and differential thermogravimetric (DTG) curves. The synthesized ligand
and its metal complexes were also screened for their antibacterial and antifungal activity against bacterial
species (Escherichia coli and Staphylococcus aureus) and fungi (Aspergillus flavus and Candida albicans). The
activity data show that the metal complexes are found to have antibacterial and antifungal activity than
the parent drug and less than the standard.
Received 21 November 2009
Received in revised form 15 February 2010
Accepted 15 March 2010
Keywords:
Sulpiride
Transition metal complexes
Spectroscopy
Molar conductance
Thermal analyses
Biological activity
© 2010 Elsevier B.V. All rights reserved.
1. Introduction
pharmacological use. The objective of this study is the isolation
and characterization of the Mn(II), Fe(III), Co(II), Ni(II), Cu(II)
Sulpiride, 2-methoxy-N-((1-propylpyrrolidine-2-yl) methyl)-5-
sulphamoyl-benzamide (Fig. 1 [1]), is a substituted benzamide
antipsychotic which is reported to be a selective antagonist of
central dopamine (D2, D3 and D4) receptors. It is also claimed
to have mood-elevating properties [2]. A literature survey also
reveals several methods for assaying SPR, involving HPLC [3],
TLC [4,5], fluorometric [6], spectrophotometric [7,8], flow injec-
tion chemiluminometric [9], capillary liquid chromatography [10],
electrophoresis [11–16], oscillopolarographic [17] and adsorptive
stripping voltammetric methods [18].
and Zn(II) complexes using spectroscopic and thermal analyses
techniques. The IR spectra are used to infer the mode of bonding of
SPR with these essentially biological active elements. The thermal
behaviour of these complexes is also studied. The antibacterial
and antifungal activities of the investigated complexes were
tested against Escherichia coli (Gram −ve), Staphylococcus aureus
(Gram +ve) and Aspergillus flavus and Candida albicans (antifungal).
Important findings are obtained.
2. Experimental
The synthesis and characterization of new metal complexes
with antibacterial agents are of great importance for under-
standing the drug–metal ion interaction and for their potential
2.1. Materials and reagents
All chemicals used were of the analytical reagent grade (AR), and
of highest purity available. They included SPR drug (Unipharma,
Egypt); Cu(II) chloride dihydrate (Prolabo); Fe(III), Co(II) and Ni(II)
chlorides hexahydrates (BDH); Zn(II) chloride dihydrate (Ubichem)
∗
Corresponding author.
E-mail address: ggenidy@hotmail.com (G.G. Mohamed).
1386-1425/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2010.03.016

342
G.G. Mohamed, M.H. Soliman / Spectrochimica Acta Part A 76 (2010) 341–347
and kept in a refrigerator for 1 h to permit diffusion on antimicro-
bial substances. The plates were incubated at 37 ◦C for 24 h in case
of bacteria and at 28 ◦C for 48 h in case of fungi. The zones of inhi-
bition were measured in mm. The mean values of inhibitions were
calculated from triple reading in each test [19,20].
The following media were used in studding the antimicrobial
properties of drug complexes. The weights are given in gram per
one-liter medium.
Fig. 1. Structure of sulpiride drug.
Nutrient agar medium (pH 7.4): It consists of beef extract (1 g),
yeast extract (2 g), peptone (5 g), sodium chloride (5 g), agar agar
(15 g) and distilled water (100 ml).
Sabouroud’s dextrose agar medium (pH 5.6): It consists of peptone
(10 g), dextrose (20 g), agar agar (15 g) and distilled water (100 ml).
and Mn(II) chloride (Prolabo). Organic solvents used included abso-
lute ethyl alcohol, diethylether, and dimethyl formamide (DMF).
These solvents were spectroscopic pure from BDH. Hydrogen per-
oxide, hydrochloric and nitric acids (MERCK) were used. De-ionized
water collected from all glass equipments was usually used in all
preparations. The test organisms were kindly supplied from the
microbiological resource center, Ain Shams University, Faculty of
Agriculture, Egypt (CAIM, Cairo Mircen), and from Bacteriolog-
ical Department of National Organization for Drug Control and
Research (NODCAR), ATCC, American type culture collection. Bacte-
rial test organisms were inoculated on nutrient agar slants for 24 h
at 37 ◦C. Yeast and fungi organisms were inoculated on Sabouroud’s
dextrose agar slants and incubated at 28 ◦C for 48 h (Jacobs and Ger-
stein, 1960). Several workers used these organisms repeatedly as
test organisms.
3. Results and discussion
The formation of metal complexes with organic compounds has
long been recognized. However, the binary complexes of the cited
drug with metal ions have not been studied yet, although they
may be an area of interest. This is because they may affect the
bioavailability of these drugs as certain metal ions were present
in relatively appreciable concentration in biological fluids [21].
3.1. Mass spectrum of the SPR drug
The electron impact mass spectrum of SPR ligand is recorded and
the important peaks and their relative intensities for the molecular
ions are shown in Scheme 1. Mass spectrum of the studied drug
is characterized by moderate to high relative intensity molecular
ion peaks at 70 eV. Scheme 1 shows a well-defined parent peak
at m/z = 98 (R.I. = 100%) which may be due to C6H13N. The other
molecular ion peaks appeared in the mass spectrum (abundance
range from 1.0% to 100%) may be attributed to the fragmentation
of SPR molecule obtained from the rupture of different bonds inside
the molecule. The suggested mechanism of fragmentation can help
in understanding the way of metabolism of the drug in the human
body.
2.2. Instruments
The molar conductance of solid complexes in DMF was
measured using Sybron-Branstead conductometer (Meter-PM.6,
E = 3406). Elemental microanalyses of separated solid chelates for
C, H, N and S were performed at the Microanalytical Center,
Cairo University. The analyses were repeated twice to check the
accuracy of the data. Infrared spectra were recorded on a Perkin-
Elmer FT-IR type 1650 spectrophotometer in wave number region
4000–400 cm−1. The spectra were recorded as KBr pellets. The
1H NMR spectra were recorded using 300 MHz Varian–Oxford
Mercury. The molar magnetic susceptibility was measured on
powdered samples using the Faraday method. The diamagnetic cor-
rection was made by Pascal’s constant and Hg[Co(SCN)4] was used
as a calibrant. The thermogravimetric (TG and DTG) and differen-
tial thermal (DTA) analyses were carried out in dynamic nitrogen
atmosphere (20 ml min−1) with a heating rate of 10 ◦C min−1 using
Shimadzu TG-60H and DTA-60H thermal analyzers.
3.2. Elemental analyses of the complexes
The results of elemental analyses listed in Table 1 suggest that
the complexes are formed in 1:2 [metal]:[SPR] ratio and they pro-
posed to have the general formulae [MCl2(L)2(H2O)2]·nH2O
[M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); n = 0–2] and
[FeCl2(HL)(H2O)3]Cl·H2O.
2.3. Synthesis of metal complexes
3.3. Molar conductance measurements
Ethanolic hot solution (60 ◦C) of appropriate metal chlorides
(0.126, 0.237, 0.240, 0.237, 0.170 and 0.172 g of Mn(II), Ni(II), Fe(III),
Co(II), Cu(II) and Zn(II), respectively, 1 mmol) in an ethanol–water
mixture (1:1) was added to the hot solution (60 ◦C) of SPR drug
(0.351 g, 2 mmol) in the same solvent (25 ml). The resulting mixture
was stirred under reflux for 2 h whereupon the complexes precipi-
tated. They were collected by filtration, washed several times with
a 1:1 ethanol:water mixture and diethyl ether.
Table 1 shows the molar conductance values of the com-
plexes. It is concluded from the results that, the divalent
metal chelates are found to have molar conductance values of
13.75–18.60 ꢁ−1 mol−1 cm2 indicating their non ionic nature and
they considered as non-electrolytes. The Fe(III) complex is found to
have a molar conductance value of 75.50 ꢁ−1 mol−1 cm2 indicating
its electrolytic nature and of the type 1:1 electrolyte.
2.4. Biological activity
3.4. IR spectral studies
The antimicrobial activities were carried out by disc diffusion
technique as described in British Pharmacopoeia (2000). Nutrient
agar was melted at 45 ◦C and inoculated by the cell suspension
(1 ml/100 ml) bacteria or yeast. The flask was shaken well and
poured in to a Petri-dish (15 cm−2 in diameter). Filter paper discs
(6 mm) Whatman No. 2 were thoroughly moistened by antibiotics
(50 ␮g), the treated discs were aseptically transferred and placed
upon the surface of the inoculated plates with tested organisms
The data of the IR spectra of SPR ligand and its complexes are
listed in Table 2. The IR spectra of the complexes are compared with
the free drug in order to determine the coordination sites that may
be involved in chelation. Upon comparison it is found that:
The ꢂasym(SO2) and ꢃsym(SO2) stretching vibrations are found in
the free SPR ligand at 1344 and 1089 cm−1. Although these bands
are not involved in chelation, the shift of these bands to higher
or lower wavenumbers in the complexes may be attributed to the

G.G. Mohamed, M.H. Soliman / Spectrochimica Acta Part A 76 (2010) 341–347
343
Table 1
Analytical and physical data of SPR metal complexes.
Complex
Colour (% yield) M.p. (◦C) % Found (calcd.)
ꢄeff. (B.M.) ꢅm (ꢁ−1 mol−1 cm2)
C
H
N
S
M
[MnCl2(L)2(H2O)2]·2H2O
C30H52Cl2N6MnO12S2
[FeCl2(L)2(H2O)2]Cl·H2O
Brown (72)
Brown (68)
Brown (62)
Green (68)
>300
>300
>300
>300
>300
>300
40.78 (40.86)
5.51 (5.90)
9.05 (9.53)
7.14 (7.26)
6.44 (6.13)
5.25
5.69
5.86
3.76
1.94
Diam.
18.60
75.50
15.40
16.20
13.75
14.60
39.57 (39.98)
41.15 (41.47)
41.66 (41.47)
41.81 (41.26)
42.39 (42.06)
5.69 (5.55)
5.81 (5.76)
5.61 (5.76)
5.27 (5.73)
5.80 (5.61)
9.26 (9.33)
9.97 (9.68)
9.86 (9.68)
9.49 (9.63)
9.84 (9.81)
7.37 (7.11)
7.08 (7.37)
7.49 (7.37)
7.50 (7.34)
7.33 (7.64)
6.08 (6.22)
6.68 (6.80)
7.05 (6.80)
7.60 (7.28)
7.16 (7.48)
C
30H50Cl3FeN6O11S2
[CoCl2(L)2(H2O)2]·H2O
C30H50Cl2CoN6O11S2
[NiCl2(L)2(H2O)2]·H2O
C30H50Cl2NiN6O11S2
[CuCl2(L)2(H2O)2]·H2O
Brownish
yellow (75)
Colourless (70)
C30H50Cl2CuN6O11S2
[ZnCl2(L)2(H2O)2]
30H48Cl2N6O10S2Zn
C
Scheme 1. Mass fragmentation pattern of SPR drug.

344
G.G. Mohamed, M.H. Soliman / Spectrochimica Acta Part A 76 (2010) 341–347
Table 2
IR spectra (4000–400 cm−1) of the SPR drug and its metal complexes.
Compound
ꢃ(C O)
ꢃ(SO2) asym
ꢃ(SO2) asym
ı( NH)
ꢃ(NH2)
ꢃ(M–O)
SPR; L
1642sh
1635sh
1634sh
1635sh
1635sh
1635sh
1635sh
1344sh
1378m
1338s
1336sh
1335sh
1335sh
1378m
1089sh
1092sh
1093m
1092sh
1092m
1092sh
1092sh
3080sh
3069m
3065m
3070m
3069m
3067sh
3070m
3485s, 3210sh
3325m, 3196m
3366s, 3328m
3327m, 3195m
3327m, 3198m
3446s, 3327m
3326sh, 3196m
–
[MnCl2(L)2(H2O)2]·2H2O
[FeCl2(L)2(H2O)2]Cl·H2O
[CoCl2(L)2(H2O)2]·H2O
[NiCl2(L)2(H2O)2]·H2O
[CuCl2(L)2(H2O)2]·H2O
[ZnCl2(L)2(H2O)2]
509w
507s
511s
511s
474m
510s
sh, sharp; m, medium; s, small; w, weak; br, broad.
25,055 cm−1 is due to ligand to metal charge transfer transition
[24].
According to the empirical formulae of the Zn(II) complex, an
octahedral geometry is proposed for this complex.
involvement of the SO2 group in hydrogen bond formation with the
adjacent atoms. The shift in the NH and NH2 stretching vibrations
can be attributed to the keto-enol form or hydrogen bond forma-
tion. The ꢂ(C O) stretching vibration is observed at 1642 cm−1 in
the free SPR ligand spectrum. However, the participation of the
amide O in chelation is ascertained from the shift of this band
to lower wavenumbers in the spectra of the complexes [22]. The
bands at 474–511 in the spectra of the metal complexes, have been
assigned to ꢂ(M–O) of the amide O mode [23].
3.6. Thermal analyses (TG, DTG and DTA) studies
Table 3 shows the TG, DTG and DTA results of thermal decom-
position of SPR drug and its metal chelates. From these results, it is
concluded that:
The TG curve of SPR drug shows two successive steps of decom-
position. The first estimated mass loss of 59.80% (calcd. 59.24%) at
150–450 ◦C, may be attributed to the decomposition of C7H8NO4S
molecule as gases. In the second step within the temperature
range from 450 to 950 ◦C, the estimated mass loss of 41.17% (calcd.
40.76%) with a complete decomposition is observed for CO, CO2,
NO, NO2,. . .,etc. gases.
The TG curves of the Fe(III) and Cu(II) chelates show four
decomposition steps in the temperature range from 50–900 to
80–800 ◦C, respectively. The first two steps may be attributed
to the loss of hydrated water (estimated mass loss = 2.77% and
calcd. = 2.00%) and Cl2 and hydrated water molecules (estimated
mass loss = 9.03%, calcd. = 10.20%) within the temperature range
from 50–120 to 80–200 ◦C for Fe(III) and Cu(II) chelates, respec-
tively. The mass losses of the 3rd and 4th steps within the
temperature range from 120–900 to 200–800 ◦C correspond to
the decomposition of 2H2O, HCl, Cl2 and C6H5NO2S and the
second ligand (estimated mass loss = 90.34%; calcd. = 89.00%) and
2H2O and 2L (estimated mass loss = 82.46%; calcd. = 82.52%) for
Fe(III) and Cu(II) chelates, respectively. These steps are accom-
panied by exothermic and endothermic peaks as given in
Table 3.
Therefore, from the IR spectra, it is concluded that SPR behaves
as neutral monodentate ligand with O donor site and binds to the
metal ions thorough the amide O.
3.5. Magnetic susceptibility and electronic spectral studies
The diffuse reflectance spectrum of the Mn(II) complex shows
three bands at 16,450, 20,850 and 26,880 cm−1 assignable to
6
6
6
4T1g → A1g, 4T2g(G) → A1g and 4T1g(D) → A1g transitions, respec-
tively [24]. The magnetic moment value is found to be 5.25 B.M.
which indicates the presence of Mn(II) complex in octahedral struc-
ture. From the diffused reflectance spectrum, it is observed that,
the Fe(III) chelate exhibits a band at 21,290 cm−1, which may be
6
assigned to the A1g → T2g(G) transition in octahedral geometry
[23,24]. The observed magnetic moment value of Fe(III) complex
is found to be 5.69 B.M., indicating octahedral geometry involving
d2sp3 hybridization in Fe(III) ion [24]. The spectrum shows also a
band at 25,470 cm−1 which may be attributed to ligand to metal
charge transfer.
The Ni(II) complex is high spin with a room temperature
magnetic moment value of 3.76 B.M., which indicates that, the
complex of Ni(II) is octahedral [24,25]. Its electronic spectrum
displays three bands, in the solid reflectance spectra at ꢃ1
On
the
other
hand
[MnCl2(L)2(H2O)2]·2H2O
and
3
3
(13,455 cm−1): 3A2g → T2g; ꢃ2 (16,253 cm−1): 3A2g → T1g(F); and
[NiCl2(L)2(H2O)2]·H2O chelates exhibit three decomposition
steps within the temperature range from 30–1000 to 40–900 ◦C,
respectively. The estimated weight losses within the temperature
ranges given in Table 3 can be attributed to the loss of hydrated
and coordinated water molecules, Cl2 and two ligand molecules.
According to the data listed in Table 3, the total mass losses of the
decomposition steps are found to be 92.99% (calcd. 92.05%) and
91.21% (calcd. 91.36%) for Mn(II) and Ni(II) complexes, respectively.
The DTA data listed in Table 3 show that these mass losses have
exothermic and endothermic peaks.
ꢃ3 (22,056 cm−1): A2g → T1g(P). The spectrum shows also a
band at 26,333 cm−1 which may be attributed to ligand to metal
charge transfer. The electronic spectrum of the Co(II) complex
gives three bands at 13,099, 16,489 and 21,489 cm−1. The region
at 26,254 cm−1 refers to the charge transfer band. The bands
3
3
4
4
observed are assigned to the transitions T1g(F) → T2g(F) (ꢃ1),
4T1g(F) → A2g(F) (ꢃ2) and 4T1g(F) → T2g(P) (ꢃ3), respectively, sug-
gesting that the Co(II) is octahedral [24,25]. The magnetic moment
value is found to be 5.86 B.M. is an indicative of octahedral geometry
[24].
4
4
The
TG
curve
of
the
[CoCl2(L)2(H2O)2]·H2O
and
The reflectance spectrum of the Cu(II) chelate shows a broad
[ZnCl2(L)2(H2O)2] chelates represent five and three decomposition
steps, respectively, as illustrated in Table 4. The decomposition
steps within the temperature range 30–265 and 140–450 ◦C
correspond to the loss of one hydrated, two coordinated and
Cl2 molecules (mass loss of 13.65%; calcd. 14.40%) and Cl2, two
coordinated and one ligand molecules (mass loss of 53.41%;
calcd. 52.45%) for Co(II) and Zn(II) chelates, respectively. The
remaining steps of decomposition within the temperature range
265–1000 and 450–850 ◦C correspond to the removal of the two
ligand molecules (mass loss of 76.56%; calcd. 76.96%) and one
band at 15,578 and 20,124 cm−1. The 2Eg and T2g states of the
2
octahedral Cu(II) ion (d9) split under the influence of the tetrag-
onal distortion and the distortion can be such as to cause the
2
2
2
three transitions 2B1g → B2g, 2B1g → Eg and 2B1g → A1g to remain
unresolved in the spectrum [24,26]. This assignment is in agree-
ment with the general observation that Cu(II) d–d transitions are
normally close in energy [24]. The magnetic moment of 1.94 B.M.
falls within the range normally observed for octahedral Cu(II) com-
plex [24,26]. A moderately intense peak observed in the range

Table 3
Thermal analyses (TG and DTA) data of SPR drug and its metal complexes.
Compound
TG range (◦C)
na
%Found (calcd.)
Mass loss
Assignment
Metallic residue
–
DTA (◦C)b
Total mass loss
101.0 (100.0)
SPR; L
150–450
450–950
1
1
59.80 (59.24)
41.17 (40.76)
Loss of C7H8NO4S
Loss of C8H15N2
200(+), 300(−), 500(+), 700(−)
30–150
1
4.50 (4.09)
Loss of 2H2O
44(+), 56(−), 92(+),117(−), 162(−),
[MnCl2(L)2(H2O)2]·2H2O
197(+), 225(−), 304(+), 522(−), 639(−)
150–500
500–1000
1
1
50.70 (50.96)
37.79 (37.00)
Loss of 2H2O, Cl2 and L
Loss of L
MnO
92.99 (92.05)
93.11 (91.00)
50–120
2
2.77 (2.00)
Loss of H2O
½Fe2O3
162(+), 250(+), 282(−), 3020(+), 454(+),
588(−), 650(−)
[FeCl2(L)2(H2O)2] Cl·H2O
[CoCl2(L)2(H2O)2]·H2O
120–450
450–900
1
1
32.77 (33.03)
57.57 (55.97)
Loss of 2H2O, HCl, Cl2 and C6H5NO2S
Loss of L
30–140
2
6.05 (6.16)
Loss of ½Cl2 and H2O
CoO
NiO
42(+), 86(−), 125(+), 198(+), 300(+),
350(−), 476(+), 630(−), 866(+)
140–265
265–520
520–1000
1
1
1
7.60 (8.24)
39.12 (39.40)
37.44 (37.56)
Loss of ½Cl2 and 2H2O
Loss of L
Loss of L
90.21 (91.36)
40–140
1
2.33 (2.07)
Loss of H2O
50(−), 224(+), 313(+), 476(+), 550(−),
700(−)
[NiCl2(L)2(H2O)2]·H2O
[CuCl2(L)2(H2O)2]·H2O
140–450
450–900
1
1
51.10 (51.73)
37.78 (37.56)
Loss of 2H2O, Cl2 and L
Loss of L
91.21 (91.36)
91.49 (92.72)
91.78 (90.53)
80–200
2
9.03 (10.20)
Loss of H2O and Cl2
CuO
ZnO
100(+), 190(−), 580(−), 600(+), 650(+),
660(−)
200–800
140–450
2
2
82.46 (82.52)
53.41 (52.45)
Loss of 2H2O and 2L
Loss of 2H2O, Cl2 and L
174(+), 239(−), 308(+), 489(+), 477(+),
628(−)
[ZnCl2(L)2(H2O)2]
450–850
1
38.37 (38.08)
Loss of L
a
n, number of decomposition steps.
(+) endothermic; (−) exothermic.
b

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G.G. Mohamed, M.H. Soliman / Spectrochimica Acta Part A 76 (2010) 341–347
Table 4
Thermodynamic data of the thermal decomposition of SPR metal complexes.
Complex
Decomposition
E* (kJ mol−1
)
A (s−1
)
ꢀS* (J K−1 mol−1
)
ꢀH* (kJ mol−1
)
ꢀG* (kJ mol−1
)
temperature (◦C)
SPR; L
30–110
400–800
53.96
115.6
1.987 × 107
5.05 × 1010
−34.65
−72.36
55.65
97.46
77.92
149.5
30–100
100–200
200–500
39.98
77.56
124.9
8.23 × 109
5.68 × 1010
7.65 × 107
−34.89
−70.55
−126.5
43.82
75.49
138.9
48.96
107.0
135.6
[MnCl2(L)2(H2O)2]·2H2O
30–115
115–230
230–325
325–470
32.95
85.73
147.4
180.2
5.49 × 109
4.28 × 106
7.44 × 1010
6.34 × 107
4.53 × 1012
6.76 × 1010
7.02 × 108
4.21 × 107
3.98 × 109
−63.88
−128.2
−162.7
−198.4
55.72
86.44
146.3
173.4
68.89
131.2
196.9
223.1
[FeCl2(L)2(H2O)2]Cl·H2O
[CoCl2(L)2(H2O)2]·H2O
25–110
110–300
300–560
540–700
560–900
53.85
105.9
167.9
203.4
205.7
−43.76
−79.77
−142.4
−213.2
−178.7
60.38
96.19
146.4
175.8
215.4
78.66
121.3
162.6
198.6
233.7
25–130
130–230
780–1000
41.88
92.95
142.7
2.45 × 107
5.19 × 1012
6.56 × 1011
5.05 × 107
3.79 × 1012
4.86 × 1011
7.26 × 107
−50.14
−93.28
−146.7
30.46
69.43
98.4
52.46
90.66
142.3
[NiCl2(L)2(H2O)2]·H2O
[CuCl2(L)2(H2O)2]·H2O
30–140
140–300
300–540
550–800
50.18
92.49
172.6
253.3
−56.14
−95.28
−166.7
−203.2
40.46
79.43
138.4
245.8
50.66
98.86
172.3
262.6
25–110
120–200
420–550
40.78
99.84
162.9
5.45 × 107
3.99 × 1012
4.06 × 1011
−46.44
−75.88
−136.3
39.46
89.43
118.4
56.86
111.7
162.3
[ZnCl2(L)2(H2O)2]
ligand molecule (mass loss of 38.37%; calcd. 38.08%) for Co(II) and
Zn(II) chelates, respectively. The DTA curves which show many
exothermic and endothermic peaks (Table 3).
The appearance of many exothermic and endothermic peaks
is due to the gaseous decomposition of the anions and ligand
molecules.
essentially on the specific control of only one biological function
and not multiple ones. The chemotherapeutic agent affecting only
one function has a highly sounding application in the field of treat-
ment by anticancer, since most anticancers used in the present time
affect both cancerous diseased cells and healthy ones which in turns
affect the general health of the patients. Therefore, there is a real
need for having a chemotherapeutic agent which controls only one
function.
3.7. Calculation of activation thermodynamic parameters
In testing the antibacterial and antifungal activity of these com-
pounds, more than one test organism was used to increase the
chance of detecting antibiotic principles in tested materials. All of
the tested compounds show a remarkable biological activity against
different types of Gram-positive (G+) and Gram-negative (G−) bac-
teria and also fungi. The data are listed in Table 5. On comparing
the biological activity of the SRL drug and its metal complexes with
the standards (tetracycline (antibacterial agent) and amphotricine
B (antifungal agent)), the following results are obtained:
The thermodynamic activation parameters of decomposition
processes of dehydrated complexes namely activation energy (E*),
enthalpy (ꢀH*), entropy (ꢀS*) and Gibbs free energy change of
the decomposition (ꢀG*) are evaluated graphically by employing
the Coats–Redfern relation [27] and the data are summarized in
Table 4. The high values of the activation energies reflect the ther-
mal stability of the complexes. The entropy of activation is found to
have negative values in all the complexes which indicate that the
decomposition reactions proceed with a lower rate than the normal
ones.
(a) Using Staphylococcus aureus (G−) and Escherichia coli
bacteria (G+): The biological activity of Co(II), Ni(II),
Cu(II) and Zn(II) complexes are higher than that of the
3.8. Structural interpretation
From the IR spectra, it is concluded that SPR behaves as neu-
tral monodentate ligand with O donor site and binds to the metal
ions thorough amide O. From the molar conductance data, the com-
plexes are considered as non electrolytes except Fe(III) complex,
it is 1:1 electrolyte. On the basis of the above observations and
from the magnetic and solid reflectance measurements, tetrahe-
dral geometry is suggested for the investigated complexes. The
strucutre of the complexes are shown in Fig. 2.
3.9. Biological activity
The main aim of the production and synthesis of any antimicro-
bial compound is to inhibit the causal microbe without any side
effects on the patients. In addition, it is worthy to stress here on the
basic idea of applying any chemotherapeutic agent which depends
Fig. 2. Structure of metal complexes of SPR drug.

G.G. Mohamed, M.H. Soliman / Spectrochimica Acta Part A 76 (2010) 341–347
347
Table 5
The antibacterial and antifungal activity of sulpiride drug and its metal complexes.
Sample
Inhibition zone diameter (mm/mg sample)
Escherichia coli (G−
)
Staphylococcus aureus (G+)
Aspergillus flavus (fungus)
Candida albicans (fungus)
SPR; L
17
12
17
23
20
19
19
32
0.0
13
11
13
24
22
15
17
34
0.0
8
10
7
15
18
10
9
7
10
11
18
21
13
12
[MnCl2(L)2(H2O)2]·2H2O
[FeCl2(L)2(H2O)2]Cl·H2O
[CoCl2(L)2(H2O)2]·H2O
[NiCl2(L)2(H2O)2]·H2O
[CuCl2(L)2(H2O)2]·H2O
[ZnCl2(L)2(H2O)2]
Tetracycline (antibacterial agent)
Amphotricine B (antifungal agent)
0.0
17
0.0
21
+, inhibition values up to 10 mm beyond control; ++, inhibition values, 11–15 mm beyond control; +++, inhibition values, 16–22 mm beyond control; ++++, inhibition values
more than 23 mm beyond control.
SPR drug and lower than tetracycline standard. In addi-
tion, the biological activity of Mn(II) complex is lower
than that of the free SPR ligand. For Fe(III) complex, its
biological activity is the same like that of SRL. The biolog-
ical activity of the complexes, therefore, follow the order
tetracycline > Co(II) > Ni(II) > Zn(II) = Cu(II) > L = Fe(III) > Mn(II).
(b) Using Aspergillus flavus fungus: The antifungal activity of
Ni(II) complex is found to be higher than that of the free
semisynthetic compounds e.g. Hickman [32]. Such compounds may
have a possible antitumour effect since Gram-negative bacteria are
considered a quantitative microbiological method testing benefi-
cial and important drugs in both clinical and experimental tumour
chemotherapy [33].
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tract infections and hospital acquired infections [28]. However, the
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Since almost all scientists working in the field of search for
new antitumours depend basically on the line of antibiotics affect-
ing Gram-negative bacteria [29–31], and since there are certain
organisms which have proved difficult to treat and most of them
are Gram-negative rods. It is therefore believed that all the com-
plexes which are biologically active against both the Gram-negative
strains may have something to do with the barrier function of the
envelope of these Gram-negative activity, acting in a way simi-
lar to that described by Brown [30] and Nikaido and Nakae [29].
Therefore, it is claimed here that the synthesis of these complexes
might be recommended and/or established a new line for search
to new antitumour particularly when one knows that many work-
ers studied the possible antitumour action of many synthetic and