New nickel(II), palladium(II), platinum(II) complexes with aromatic methanesulfonylhydrazone based ligands. Synthesis, spectroscopic characterization and in vitro antibacterial evaluation

Article abstract of DOI:10.1016/j.ica.2013.01.031

Methanesulfonicacid hydrazide (a sulfonamide compound, msh: CH ₃SO₂NHNH₂) derivatives: salicylaldehydemethanesulfonylhydrazone (salmsh), 2- hydroxyacetophenonemethanesulfonyl hydrazone (afmsh), 2-hydroxy-3- metoxybenzaldehydemethanesulfonylhydrazone (o-vanmsh) and their Ni(II), Pd(II) and Pt (II) complexes have been synthesized. The structure of these compounds has been investigated by using elemental analyses; FT-IR, ¹H- NMR, LC - MS, UV-Visible spectrometric methods; magnetic susceptibility; conductivity measurements; thermal studies. The antibacterial activities of synthesized compounds have been determined in vitro against gram positive bacteria; Staphylococcus aureus ATCC 25923, Bacillus cereus RSKK 709, and gram negative bacteria; Pseudomonos aeruginosa ATCC 27853, Escherichia coli ATCC 35268 by paper disc diffusion and microdilution broth methods. The biological activity screening showed that metal complexes have more activity than their ligands against the tested bacteria.

Full text of DOI:10.1016/j.ica.2013.01.031

Inorganica Chimica Acta 400 (2013) 13–19
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
New nickel(II), palladium(II), platinum(II) complexes with aromatic
methanesulfonylhydrazone based ligands. Synthesis, spectroscopic
characterization and in vitro antibacterial evaluation
a
b
Ümmühan Ö. Özdemir a, , Nesrin Akkaya , Neslihan Özbek
⇑
a Department of Chemistry, Faculty of Science, Gazi University, 06500 Teknikokullar, Ankara, Turkey
b Department of Chemistry, Faculty of Education, Ahi Evran University, 40100 Kırßsehir, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 13 July 2012
Received in revised form 11 January 2013
Accepted 23 January 2013
Available online 14 February 2013
Methanesulfonicacid hydrazide (a sulfonamide compound, msh: CH3SO2NHNH2) derivatives: salicylalde
hydemethanesulfonylhydrazone (salmsh), 2-hydroxyacetophenonemethanesulfonyl hydrazone (afmsh),
2-hydroxy-3-metoxybenzaldehydemethanesulfonylhydrazone (o-vanmsh) and their Ni(II), Pd(II) and Pt
(II) complexes have been synthesized. The structure of these compounds has been investigated by using
elemental analyses; FT-IR, 1H NMR, LC–MS, UV–Visible spectrometric methods; magnetic susceptibility;
conductivity measurements; thermal studies. The antibacterial activities of synthesized compounds have
been determined in vitro against gram positive bacteria; Staphylococcus aureus ATCC 25923, Bacillus
cereus RSKK 709, and gram negative bacteria; Pseudomonos aeruginosa ATCC 27853, Escherichia coli ATCC
35268 by paper disc diffusion and microdilution broth methods. The biological activity screening showed
that metal complexes have more activity than their ligands against the tested bacteria.
Keywords:
Aromatic methanesulfonylhydrazone
Ni(II)
Pd(II)
Pt(II) complexes
Sulfonamide derivatives
Antibacterial activity
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
complexes have been discovered with significant anti-tumor activ-
ity against different tumor cells including these resistant to cis-
Sulfonyl hydrazones, derivatives of sulfonamide, exhibit several
medicinal applications. For example, 4-substituted benzenesulfo-
nylhydrazone has been studied for antibacterial activities [1],
benzaldehyde arylsulfonylhydrazones possess antineoplastic activ-
ity against human stomach cancer SGC 7901 [2], N-arylsulfonyl
hydrazones have been identified as novel inhibitors of IMP-1 a
metallo-b-lactamase enzyme [3], imidazol[1,2-a] pyridines with
arylsulfonylhydrazone substituents have been reported as novel
PI3 kinase p110a inhibitors [4].
N-arylsulfonyl-3-acylindole derivatives have displayed potent
anti-human immunodeficiency virus type 1 (HIV-1) activity [5].
In addition, numerous sulfonamide derivatives have been reported
as carbonic anhydrase inhibitors [6], anticancerous [7] and anti-
inflammatory agents [8]. Transition metal complexes of hydrazides
and sulfonamides also find application in chemotherapy as well as
their hydrazone derivatives [9]. Especially, the search for platinum
(II) complexes with anti-tumor properties has been going on
through the efforts of chemists from the medicinal chemistry field
since the discovery of the anti-proliferation activity of cisplatin in
the 1960s [10]. However, since the 1990s many trans platinum
platin [11–13]. Owing to the similar co-ordination modes of the
cation Pd(II) and Pt(II) (d8-electron configuration) there has also
been renewed interest in attempts to obtain activity for cis and
trans palladium(II) complexes [14–16]. Furthermore, some mixed
ligand palladium(II) complexes have been shown to act as poten-
tial anticancer agents [17–19].
In our previous studies, we reported the antibacterial and
cytotoxic effect of methanesulfonic acid hydrazide and its sulfonyl-
hydrazone derivatives [20–22], as well as its metal carbonyl com-
plexes [23,24]. Methane, ethane and prophanesulfonylhydrazone
derivatives and their transition metal complexes were synthesized
and screened for antimicrobial activity [25–27]. Furthermore,
ethanesulfonylhydrazone derivatives and their transition metal
complexes were investigated inhibitory effects on carbonic anhy-
drase II (CA II) enzyme [26].
As part of our ongoing studies, methanesulfonicacid hydrazide
(sulfonamide compound) and its derivatives: salicylaldehydemeth
anesulfonylhydrazone (salmsh), 2-hydroxyacetophenone metha-
nesulfonylhydrazone (afmsh) and 2-hydroxy-3-metoxy benzalde
hydemethanesulfonyl hydrazone (o-vanmsh) were synthesized.
The structure of salmsh and afmsh ligands were reported in our pre-
vious work [20,28]. Ni(II) Pd(II) and Pt(II) complexes of aromatic
methanesulfonylhydrazone derivatives and ovanmsh ligand were
synthesized for the first time and characterized by using elemental
⇑
Corresponding author. Fax: +90 312 2122279.
E-mail address: ummuhan@gazi.edu.tr (Ü.Ö. Özdemir).
0020-1693/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.ica.2013.01.031

14
Ü.Ö. Özdemir et al. / Inorganica Chimica Acta 400 (2013) 13–19
analysis, FT-IR, LC–MS, UV–Visible spectrometric methods, mag-
netic susceptibility, conductivity measurements and thermal stud-
ies. The antibacterial activities of synthesized compounds have
been determined in vitro against gram positive bacteria; Staphylo-
coccus aureus ATCC 25923, Bacillus cereus RSKK 709, and gram neg-
ative bacteria; Pseudomonas aeruginosa ATCC 27853, Escherichia
coli ATCC 35268 by paper disc diffusion and microdilution broth
methods.
plexes formed was collected by filtration, washed with a small vol-
ume of methanol and ether, and then, were left in glass oven at
170 °C for a 2 h in vacuo to prevent the hydration dried in a desic-
cators over CaCl2.
2.4. Procedure for antibacterial activity
The in vitro antibacterial activity of the free ligands and their
complexes were tested against the gram positive bacteria; S. aureus
ATCC 25923, B. cereus RSKK 709, and gram negative bacteria, P.
aeruginosa, ATCC 27853, E. coli ATCC 35268 by paper disc diffusion
and micro dilution broth methods.
2. Experimental
2.1. Physical measurements
Bacteria cultures were obtained from Gazi University, Biology
Department. Bacterial strains were cultured overnight at 310 K in
Nutrient Broth. During the survey, these stock cultures were stored
in the dark at 277 K. The inocula of microorganisms were prepared
from 12 h broth cultures and suspensions were adjusted to 0.5
McFarland standard turbidity.
The solvents used were purified and distilled according to
routine procedures. Methane sulfonyl chloride, hydrazine hydrate,
salicylaldehyde, 2-hydroxyacetophenone, 2-hydroxy-3-metoxy-
benzaldehyde and anhydrous nickel , palladium and platinum
chloride were commercial products (purum). The elemental analy-
ses (C, H, N and S) were performed on a LECO–CHSNO – 9320 type
elemental analyzer. 1H NMR spectra of dimethylsulfoxide-d6
(DMSO-d6) solutions of the compounds were recorded on a Bruker
WM-400 spectrometer (400 MHz) using tetra methyl silane as
internal standard. D2O-exchange was applied to confirm the
assignment of the NH- and OH-signals .The infrared spectra of
the compounds as KBr-disks were recorded in the range of 4000–
400 cmꢀ1 with a Mattson 1000 FT spectrometer. UV–Vis spectra
2.4.1. Disc diffusion method
The synthesize compounds and complexes were dissolved in
dimethylsulfoxide (20% DMSO) to a final concentration of 5.0 mg
mLꢀ1 and sterilized by filtration by 0.45
l
m Millipore filters. Anti-
microbial tests were then carried out by the disc diffusion method
using 100
L of suspension containing 108 CFU mLꢀ1 bacteria
spread on a nutrient agar (NA) medium. The discs (6 mm in diam-
l
_
were recorded on UNICAM-UV 2-100 spectrophotometer. Melting
eter) were impregnated with 20
lL of each compound (100 lg/
disc) at the concentration of 5.0 mg mLꢀ1 and placed on the inoc-
ulated agar. DMSO impregnated discs were used as negative con-
points of aromatic methanesulfonylhydrazone derivatives were
determined with a Gallenkamp melting point apparatus. The molar
magnetic susceptibilities were measured on powdered samples
using Gouy method. The molar conductance measurements were
carried out using a Siemens WPA CM 35 conductometer. A Du Pont
Instrument 951 thermal analyzer was used to record simulta-
neously TG and DTA curves. The experiments were carried out in
dynamic nitrogen atmosphere (20 ml minꢀ1) with a heating rate
of 10 °C minꢀ1 in the temperature range 30–400 °C using platinum
crucibles. The microdilution broth and disc diffusion method were
used to determine the antibacterial activity of compounds against
the bacteria; S. aureus ATCC 25923, B. cereus RSKK 709, P. aeruginosa
ATCC 27853, E. coli ATCC.
trol. Sulfamethoxazole (300 lg/disk) and sulfisoxazole (300 lg/
disk) were used as positive reference standards to determine the
sensitivity of one strain/isolate in each microbial species tested.
The inoculated plates were incubated at 37 °C for 24 h for bacterial
strains isolates. Antimicrobial activity in the disc diffusion assay
was evaluated by measuring the zone of inhibition against the test
organisms. Each assay in this experiment was repeated twice [29].
The values obtained are average of the two results. Percentage of
inhibition by comparing distance of the compounds to the positive
control using (sulfamethoxazole) the equation below [30]:
ꢀ
ꢁ
diameter of the sample
diameter of the positive control
%Inhibition ¼
ꢁ 100:
2.2. Synthesis of ligands
The procedure of preparation of aromatic methanesulfonylhyd-
razone derivatives are similar to that applied by us [27]. Thus, solu-
tion of 1.10 g (10 mmol) methanesulfonicacid hydrazide in 5 ml of
ethanol was mixed with hot solution of 12 mmol of the corre-
sponding carbonyl compound (salicylaldehyde, 2-hydroxyaceto-
2.4.2. Micro dilution assays
The inocula of microorganisms were prepared from 12 h broth
cultures and suspensions were adjusted to 0.5 McFarland standard
turbidity. The test compounds dissolved in 20% dimethylsulfoxide
(DMSO) were first diluted to the highest concentration (8.0 mg
mLꢀ1) to be tested, and then serial, twofold dilutions were made
phenone,2-hydroxy-3-metoxybenzaldehyde
respectively)
in
in a concentration range from 15.625 to 4000 l
g mLꢀ1 in 10 mL
10 ml of ethanol and stirred for 1 h. Upon cooling, the obtained
crystalline precipitates were filtered, washed with ethanol–ether,
recrystallized from water and dried in vacuo over P2O5. They are
light yellow crystalline solids, stable at normal conditions and sol-
uble in methanol, ethanol, acetonitrile, dimethylformamide,
DMSO; poorly soluble in benzene and water.
sterile test tubes containing nutrient broth. The MIC values of each
compound against bacterial strains were determined based on a
micro-well dilution method.
The 96-well plates were prepared by dispensing 95
ent broth and 5 L of the inoculums into each well. One hundred
microliters from each of the test compounds initially prepared at
the concentration of 4000
g mLꢀ1 was added into the first wells.
Then, 100 L from each of their serial dilutions was transferred
into nine consecutive wells. The last well containing 195 L of
nutrient broth without compound, and 5 L of the inoculum on
each strip, was used as negative control. The final volume in each
well was 200 L. The contents of the wells were mixed and the mi-
lL of nutri-
l
2.3. Synthesis of Ni(II), Pd(II), Pt(II) complexes
l
l
All complexes are prepared by the following general method. A
sample of anhydrous MCl2 (M = Ni, Pd, Pt) (0.53 mmol) was dis-
solved in a mixture of methanol and acetonitrile (25 mL), and solu-
tion of methanesulfonylhydrazone derivatives (1.60 mmol) in a
mixture of acetonitrile (25 mL) and NaOH solution in methanol
(1.60 mmol) was added. The reaction mixture was heated under
reflux for 1 h, at 40 °C and left in ice bath for 3 h. The solid com-
l
l
l
cro plates were incubated at 37 °C for 24 h. All compounds tested
in this study were screened twice against each microorganism
and the average was taken. The MIC was defined as the lowest

Ü.Ö. Özdemir et al. / Inorganica Chimica Acta 400 (2013) 13–19
15
Table 1
Analytical and physical data for aromatic methanesulfonylhydrazone derivatives and their complexes.
Compound
Empirical formula (formula weight)
Color
M.p. (°C)
Yield (%)
Found (calculated)
%C
%H
%N
%S
salmsh
C8H10N2SO3
214.11
C9H12N2SO3
228.12
C9H12N2SO4
244.11
C16H18N4S2O6Ni
484.93
C16H18N4S2O6Pd
532.62
C16H18N4S2O6Pt
621.31
C18H22N4S2O6Ni
512.95
C18H22N4S2O6Pd
560.64
C18H22N4S2O6Pt
649.33
C18H22N4S2O8Ni
544.93
C18H22N4S2O8Pd
592.93
C18H22N4S2O8Pt
681.31
White
149–150
161–162
120–121
275>
50
55
40
40
50
35
45
40
40
35
40
30
44.38
(44.87)
49.1
4.49
(4.67)
5.3
(5.8)
4.65
(4.91)
3.99
(3.71)
3.25
(3.37)
2.59
(2.89)
4.00
(4.28)
4.3
(4.7)
5.1
(5.4)
3.85
(4.03)
3.01
(3.71)
3.14
12.92
(13.07)
11.5
(11.6)
10.92
(11.47)
11.76
(11.54)
9.88
(10.51)
8.81
(9.01)
9.90
(10.91)
9.9
(10.2)
9.0
(9.4)
9.50
14.41
(14.97)
13.0
afmsh
White
(49.5)
44.02
(44.27)
40.63
(39.62)
35.85
(36.07)
29.98
(30.92)
41.80
(42.14)
39.2
(13.2)
12.50
(13.13)
11.33
(13.22)
11.75
(12.03)
10.03
(10.32)
11.55
(12.05)
11.2
(11.7)
10.6
(10.8)
10.98
(11.76)
9.85
o-vanmsh
Light yellow
Green
Ni(salmsh)2
Pd(salmsh)2
Pt(salmsh)2
Ni(afmsh)2
Pd(afmsh)2
Pt(afmsh)2
Ni(ovanmsh)2
Pd(ovanmsh)2
Pt(ovanmsh)2
Orange
Light brown
Green
248>
258>
242>
Orange
Brown
260>
(39.3)
39.9
220>
(40.4)
39.06
(39.67)
34.95
(36.45)
30.85
(31.73)
Green
234>
(10.27)
8.84
(9.44)
8.76
Orange
Brown
260>
(10.81)
9.65
(9.41)
230>
(3.22)
(8.22)
concentration of the compounds to inhibit the growth of microor-
ganisms [31].
Table 3
1H NMR spectroscopic data for aromatic methanesulfonylhydrazone derivatives in
DMSO-d6 (ppm).
3. Results and discussion
Assign.
salmsha
afmsha
ovanmsh
Analytical data and some physical properties of aromatic meth-
anesulfonylhydrazone and their complexes are listed in Table 1.
The elemental analysis results show 1:2 (metal:ligand) stoichiom-
etry for all the complexes. The analytical results are in good agree-
ment with those required by the general formula (ML2).The molar
conductivity (Km) of 10ꢀ3 M solutions of the complexes in MeOH
at 25 °C were measured and all the complexes were found non-
CH3C@N
SO2CH3
OCH3
CH@N
NH
–
2.31 (s, 3H)
3.08 (s, 3H)
–
–
3.06 (s, 3H)
–
8.27 (s, 1H)
10.21 (s, br)
6.88–7.60 (mH)
11.00 (s, br)
2.95 (s, 3H)
3.86 (s, 3H)
8.17 (s, 1H)
10.20 (s, 1H)
6.80–7.10 (mH)
11.06 (s, 1H)
–
10.45 (s, 1H)
6.89–7.55 (mH)
11.68 (s, 1H)
Ar
OH
a
Taken from [20].
electrolytic nature in the range of 3.3–5.9 ꢀ1 cm2 molꢀ1
.
bands are shifted to lower wave number in all complexes. These
shifts support the participation of the imine group of these ligands
in binding to the metal ions [25–27]. Ligands also display bands at
3.1. The characterization of compounds
3.1.1. IR spectra
The important diagnostic i.r. bands of aromatic metha-
nesulfonylhydrazone and their complexes are summarized in Table
2. Bands in the region of 3210, 3203 and 3217 cmꢀ1 may be due to
1268, 1232 and 1247 cmꢀ1 which are assigned to
m(C–O) stretching
vibrations for salmsh, afmsh, ovanmsh respectively. These bands are
strongly affected by chelation through the phenolic-CO groups of
the aromatic methanesulfonylhydrazone and the shift to higher
wave numbers indicates the coordination of phenolic-O donor
atoms [32].
m
(NH) stretching vibration for salmsh, afmsh and ovanmsh. The
strong bands at 1624, 1622 and 1618 cmꢀ1 are assigned to
(C@N) stretching mode of the imine group for ligands. These
m
Table 2
Major i.r. absorption bands (cmꢀ1) of aromatic methanesulfonyl hydrazone derivatives and their complexes.
Assign
Comp.
(NH)
m
m
(C@N)
mas(SO2)
m
(CO)
m
s(SO2)
d(NH)
d(SO2)
salmsh
afmsh
o-vanmsh
3210s
3203s
3217s
3127s
3180s
3203s
3210s
3196s
3210s
3198s
3210s
3208s
1624s
1622s
1618s
1608s
1602s
1602s
1606s
1578s
1600s
1604s
1600s
1600s
1320s
1322s
1320s
1320s
1321s
1319s
1324s
1340s
1324s
1320s
1317s
1317s
1268s
1232s
1152s
1153s
1159s
1154s
1157s
1154s
1155s
1157s
1159s
1159s
1143s
1143s
670w
626m
651m
652m
660m
678m
625m
623m
628m
647m
650m
650m
524m
515m
520m
522m
527m
539m
519m
515m
520m
514m
520m
542m
1247m
1277m
1290m
1295m
1259m
1273m
1254m
1257m
1265m
1265m
Ni(salmsh)2
Pd(salmsh)2
Pt(salmsh)2
Ni(afmsh)2
Pd(afmsh)2
Pt(afmsh)2
Ni(ovanmsh)2
Pd(ovanmsh)2
Pt(ovanmsh)2

16
Ü.Ö. Özdemir et al. / Inorganica Chimica Acta 400 (2013) 13–19
Table 4
The mass spectral data of aromatic methanesulfonyl hydrazone complexes.
Compounds
MW
Relative intensities of the major ions (m/z, %) and assignment
Ni(salmsh)2
Pd(salmsh)2
Pt(salmsh)2
Ni(afmsh)2
Pd(afmsh)2
Pt(afmsh)2
Ni(o-vanmsh)2
Pd(o-vanmsh)2
Pt(o-vanmsh)2
484.93
532.62
621.31
512.95
560.64
649.33
544.93
592.93
681.31
[Mꢀ2H]+ (482.0, 30%), [L+H]+ (215.06, 100%)
[M]+ (532.97, 79%), [MꢀH]+(531.0, 45%), [M+Na]+ (554.96, 9%), [L+H]+ (215.04, 100%)
[M+Na]+ (644.20, 10%), [ L+CH3]+ (229.90, 100%)
[Mꢀ2H]+ (510.03, 20%), [M]+ (511.0, 3%], [L+H]+ (229.05, 100%)
[M]+ (561.01, 28%), [M+Na]+ (582.9, 62%), [L+H]+ (229.03, 100%)
[MꢀCH3]+ (634.1, 30%), [L+H]+ (229.07, 100%)
[Mꢀ2H]+ (542.0, 40.1%), [L+H]+ (245.04, 100%)
[M]+ (592.9, 5.1%), [LꢀOCH3]+ (211.9, 5%)
[MꢀCH3]+ (666.1, 20%), [L+H]+ (245.05, 100%)
Table 5
Inhibition zone of aromatic methanesulfonylhydrazone derivatives and their complexes by disc diffusion method (mm).
Compounds (
lg/mL)
Diameter inhibition zone* (mm, 100
Gram-positive
lg/disk)
Gram-negative
S. aureus ATCC 25923
B. cereus RSKK 709
P. aeruginosa ATCC 27853
E. coli ATCC 35268
salmsh
afmsh
13
12
14
15
16
15
10
15
13
12
18
16
15
25
12
10
13
-
16
13
–
10
7
10
8
o-vanmsh
Ni(salmsh)2
Pd(salmsh)2
Pt(salmsh)2
Ni(afmsh)2
Pd(afmsh)2
Pt(afmsh)2
Ni(o-vanmsh)2
Pd(o-vanmsh)2
Pt(o-vanmsh)2
SD1
14
12
14
11
11
12
14
14
15
11
17
8
11
11
13
12
–
11
12
14
16
13
17
20
12
8
10
16
14
28
17
SD2
SD1: Sulfamethoxazole (300
Average values.
l
g/disk), SD2: sulfisoxazole (300
lg/disk). <10: weak; >10 moderate; >16: significant.
*
3.1.2. NMR spectra
11.00 ppm; 10.45 ppm and 11.68 ppm; 10.20 ppm and 11.06 ppm
are assigned to the NH and OH protons, respectively for salmsh,
afmsh and ovanmsh. The high field shift of NH protons may be
due to the involvement of this group with a hydrogen bond in
DMSO-d6, which is well known for its interaction with an amide
proton [33].
1H NMR data of DMSO-d6 solutions of the aromatic metha-
nesulfonylhydrazone are collected in Table 3. salmsh and ovanmsh
show signals at 8.27–8.17 ppm which are attributed to the imines
protons (–N@CH –). afmsh (ketone derivative) show signals at
2.31 ppm which is attributed to the –CH3C@N– protons [26].
The signals of the HC@N and CH3C@N protons show no split-
ting, and the positions of the signals of the ring protons are typical.
In general, the multiplates observed at 6.88–7.60 ppm, 6.89–
7.55 ppm and 6.80–7.10 ppm are assigned to salmsh, afmsh and
ovanmsh ring protons; respectively. Signals at 10.21 ppm and
3.1.3. Mass spectra
LC–MS data of aromatic methanesulfonyl hydrazone complexes
are summarized in Table 4. LC–MS spectra shows that [Ni
(salmsh)2], [Ni(afmsh)2], and [Ni(ovanmsh)2], give the molecular
Table 6
The MIC’s (lg/mL) values of aromatic methanesulfonyl hydrazone derivatives and their complexes.
Compounds
MIC*
(lg/mL)
Gram-positive
Gram-negative
S. aureus ATCC 25923
B. cereus RSKK 709
P. aeruginosa ATCC 27853
E. coli ATCC 35268
salmsh
afmsh
250
500
31.25
500
62.50
250
500
125
125
500
125
500
62.5
500
250
500
500
250
500
500
31.25
62.5
16
1000
1000
500
1000
500
1000
2000
250
1000
500
1000
1000
500
1000
500
1000
2000
1000
500
1000
500
o-vanmsh
Ni(salmsh)2
Pd(salmsh)2
Pt(salmsh)2
Ni(afmsh)2
Pd(afmsh)2
Pt(afmsh)2
Ni(o-vanmsh)2
Pd(o-vanmsh)2
Pt(o-vanmsh)2
SD1
31.25
31.25
32
500
2000
64
1000
64
SD2
93.75
375
375
23.5
SD1: Sulfamethoxazole, SD2: sulfisoxazole.
*
Average values.

Ü.Ö. Özdemir et al. / Inorganica Chimica Acta 400 (2013) 13–19
17
Table 7
The MIC’s values of aromatic methanesulfonylhydrazone derivatives and their complexes (mM of 20% DMSO).
Compounds
Gram-positive
Gram-negative
S. aureus ATCC 25923
B. cereus RSKK 709
P. aeruginosa ATCC 27853
E. coli ATCC 35268
salmsh
afmsh
1.167
2.192
0.128
1.031
0.058
0.050
0.974
0.223
0.1925
0.917
0.052
0.046
0.126
0.351
0.584
2.192
0.256
1.031
0.469
0.805
0.974
0.446
0.770
0.917
0.052
0.092
0.063
1.403
4.670
4.383
2.048
2.06
4.670
4.383
2.048
2.06
o-vanmsh
Ni(salmsh)2
Pd(salmsh)2
Pt(salmsh)2
Ni(afmsh)2
Pd(afmsh)2
Pt(afmsh)2
Ni(o-vanmsh)2
Pd(o-vanmsh)2
Pt(o-vanmsh)2
SD1
0.938
1.609
3.900
0.446
1.540
0.917
0.844
2.935
0.253
1.403
0.938
3.219
3.900
1.784
0.770
1.835
0.844
1.468
0.253
0.088
SD2
SD1: Sulfamethoxazole, SD2: sulfisoxazole.
Fig. 1. Comparison of antibacterial activite of ligands, metal (II) complexes.and antibiotics.
ions, [NiL2+2H]+ with the expected m/z values (intensity %) = 482.0
(30.0), 510.03 (20.0) and 542.0 (40.1), [L+H]+ fragments are ob-
served at 215.0 (100.0) , 229.05 (100.0) and 245.0 (100.0) as main
peak for salmsh, afmsh and ovanmsh; respectively. [Pd(salmsh)2],
[Pd(afmsh)2], and [Pd(ovanmsh)2], give the molecular ion peaks,
[PdL2]+ at the desired positions : m/z (intensity %) = 532.9 (79.0),
561.01 (28.0) and 592.0 (5.1). [Pt(afmsh)2], [Pt(ovanmsh)2], give
the molecular ions, [PtL2ꢀCH3]+ at the desired positions. m/z
(intensity %) = 634.1 (30), 666.1 (20) and [Pt(salmsh)2] gives molec-
ular ion, [PtL2+Na]+ at 621.20 (10).
3.1.4. Electronic spectra and magnetic behavior
The significant electronic spectra of the complexes are recorded
in methanol. The important bands of the ligands and the
Fig. 2. Average antibacterial activity of ligands and metal (II) complexes.

18
Ü.Ö. Özdemir et al. / Inorganica Chimica Acta 400 (2013) 13–19
Fig. 3. Percentage of inhibition of ligands and metal (II) complexes.
complexes are observed in the region of 294–245 nm and 340–
313 nm. These may be attributed, respectively, to
p⁄ type
220–700 °C which means all complexes does not contain any
coordinated or crystal water molecules [27].
p
?
and charge-transfer transitions. The spectra of the Ni2+, Pd2+ and
Pd2+ complexes show bands in the range of 460–498 nm. Hence,
square-planar structures may be assigned to these complexes [34].
The magnetic moments of complexes (as B.M.) were measured
at room temperature. The diamagnetic character of the nickel(II),
platinum (II) and palladium (II) complexes shows square-planar
geometry for these complexes.
3.2. Antibacterial activity results
The test compounds were screened in vitro for their antibacte-
rial activity against two Gram-positive species (B. cereus and S. aur-
eus) and two Gram-negative species (E. coli and P. aeruginosa) of
bacterial strains by the disc diffusion and micro dilution methods.
The antibacterial results were given in Table 5 by disc diffusion and
Tables 6 and 7 micro dilution methods. The results were compared
with those of the standard drugs sulfamethoxazole and sulfisoxa-
zole (Figs. 1 and 2).
3.1.5. Thermal decomposition studies
The Ni(II), Pd(II) and Pt(II) complexes were left in glass oven at
170 °C for a 2 h in vacuo to prevent the hydration. The thermo
grams of anhydrous of all complexes were observed in the range
of 35–700 °C. As expected there was no mass loss up to 220 °C.
All complexes have thermally decompose in the range of
As the disc diffusion assay results evidently show (Table 5, Figs.
1 and 2) that o-vanmsh has exhibited the strong inhibition effect
against most of test bacteria whereas salmsh and afmsh have
O
O
H3C
S
R1
C
NH
N
OH
R2
R1=H R2=H; salmsh
R1=CH3 R2=H; afmsh
R1=H R2=OCH3;ovanmsh
(a)
H3C SO2
R2
R1
C
NH
N
O
C
R1
M
O
N
HN
R2
SO2
H3C
R1=H, R2=H;
M=Ni; Nisalmsh; M=Pd;Pdsalmsh; M=Pt;Ptsalmsh
M=Ni; Niafmsh; M=Pd;Pdafmsh; M=Pt;Ptafmsh
R1=CH3,R2=H;
R1=H, R2=OCH3; M=Ni; Niovanmsh;M=Pd;Pdovanmsh; M=Pt;Ptovanmsh
(b)
Fig. 4. Structures of ligands (a) and complexes (b).

Ü.Ö. Özdemir et al. / Inorganica Chimica Acta 400 (2013) 13–19
19
weaker activity. The structure–activity relationships (SAR) suggest
that both methoxy and azomethine (–NH–N@CH–) groups contain-
ing o-vanmsh have important effects on maximum antibacterial
activity. Similar results were also reported by Govindasami et al.
[35].
activity screening showed that complexes have more activity than
ligands against the tested bacteria. Furthermore, our Pd(II) and
Pt(II) complexes showed the most activity against all bacteria.
Acknowledgement
All ligands and their complexes show the highest activities
against S. aureus which is the mostly effected by Pd(o-vanmsh)2
having the diameter zone of 18 mm.
The authors would like to thank Gazi University BAP (Grant No:
05/2012-12) for the financial support of this project.
All compounds except afmsh have moderate activity against P.
aeruginosa at in the diameter zone of 10–15 mm whereas sulfisox-
azole, the drug used as standard, has been found less active (8 mm)
against the bacteria mentioned above. The aromatic metha-
nsulfonylhydrazone complexes show remarkable increase in anti-
microbial activity than the parent ligands.
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In this study we have reported the synthesis of aromatic meth-
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a bidentate
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