Synthesis, electrochemical, and antibacterial activity of some novel N 4O2 ligand derivativies

Article abstract of DOI:10.1134/S1070363208070311

A novel ligand has been synthesized by the condensation of 1,3-diaminoprophane (HL) wIth isonitroso-p-chloroacetophenone. The complexes of cobalt(II), nicel(II), cupper(II) and zinc(II) with HL were prepared. All compounds were characterized by spectroscopic techniques and its antibacterial activities were determined by the disc diffusion method used against to those gram-positive and-negative bacteria. All compounds were investigated by cyclic voltammetry at 25°C. The voltammograms were recorded with a potential scan of 100 mV s^-1.

Full text of DOI:10.1134/S1070363208070311

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 7, pp. 1458–1462. © Pleiades Publishing, Ltd., 2008.
Synthesis, Electrochemical, and Antibacterial Activity
of Some Novel N4O2 Ligand Derivativies1
Ibrahim Demira, Ertugrul Sahmetlioglua, Gokcen Y. Celikb, and Murat Unala
aNigde Universty, Faculty of Science and Arts, Department of Chemistry, Nigde, Turkey,
phone: +90 388 225 2093
fax: +90 388 225 0180
e- mail: idemir@nigde.edu.tr, ibrahimdemir75@gmail.com
bNigde Universty, Faculty of Science and Arts, Department of Biology, Nigde, Turkey
Received March 11, 2008
Abstract—A novel ligand has been synthesized by the condensation of 1,3-diaminoprophane (HL) wıth
isonitroso-p-chloroacetophenone. The complexes of cobalt(II), nicel(II), cupper(II) and zinc(II) with HL were
prepared. All compounds were characterized by spectroscopic techniques and its antibacterial activities were
determined by the disc diffusion method used against to those gram-positive and -negative bacteria. All
compounds were investigated by cyclic voltammetry at 25°C. The voltammograms were recorded with a potential
scan of 100 mV s–1.
DOI: 10.1134/S1070363208070311
elemental analyses show that the metal to ligand ratio
is 1 : 1 in all the complexes. The composition of the
complexes is [ML2]· nH2O for all complexes (n = 0 or
2). The Schiff base ligand is soluble in common
organic solvents. All complexes are soluble in DMF,
DMSO and insoluble in the other organic solvents.
INTRODUCTION
Oximes and their metal complexes have been
widely recognized. The early studies on oxime
complexes have been reviewed by Chakravorty [1].
Then Tschugaeff isolated dimethylglyoxime Co(III)
complexes which played an important role as model
compounds for study some biological and biochemical
mechanisms [2]. Some oximes and their metal
copmlexes are widely used for various purposes in
organic, analytical, inorganic, bio and industrial
chemistry. For example, Pt vic-dioximes complexes
have been studied as anti-tumor agents in
chemotherapy [3]. Liquid crystal properties of some
vic-dioxime complexes have been studied and further
applications include column packing material in
chromatographic separation of nucleotides and
nucleosides after binding to natural resins as func-
tional groups [4, 5]
Infrared Spectra
The tentative assignments of the most characteristic
IR bands were observed and are given in Table 1. The
vibration of the sterically hindered oxime groups of the
free Schiff base ligand HL is observed at 3400–3500 cm–1
respectively [6, 7]. When the spectra of the complexes
are compared with that of the uncomplexed Schiff
base ligand the ν(C=N) band are shifted to lower
frequency [8].This indicated that the imine nitrogen is
coordinated to the metal ion. A weak and broad band
occurring around 3450–3455 cm–1 may be attributed to
the ν(O–H) which takes places in the complex of the
hydrated water molecule with Co metal ion. The
spectra of complexes show a few expected absorption
bands 520–560 cm–1 and 450–465 cm–1 ranges
assigned to ν(M–N) [9] and ν(M–O) [10, 11].
In this study, new Schiff base ligand (as shown in
Fig. 1) and its transition metal complexes were
synthesized and the type of coordination which takes
place to the metal ions were interpreted. Furthermore
we have investigated antibacterial and electrochemical
activity of these compounds.
RESULT AND DISCUSSION
The analytical data for the ligand and its metal
complexes are listed in Table 1. The result of the
1
Fig. 1. Structure of the Ligand HL, R= (CH2)3.
The text was submitted by the authors in English.
1458

SYNTHESIS, ELECTROCHEMICAL, AND ANTIBACTERIAL ACTIVITY
Table 1. Infrared spectral data of the free ligand and its complex
1459
Compound
HL
ν(OH)a
ν(OH)b
ν(C=N)im
ν(C=N)ox
ν(C–N)
ν(C–Cl)
ν(M–N)
ν(M–O)
–
3400–3500
1643
1605
1107
740
–
–
[CoL2]·2H2O
[NiL2]
3450
–
–
–
–
1620
1610
1618
1613
1600
1603
1600
1603
1097
1100
1100
1137
750
760
745
755
520
560
555
545
465
460
455
450
–
–
–
[CuL2]
[ZnL2]
a ν(OH) is a vibration of the hydrated water molecule; b ν(OH) is a vibration of sterically hindered oxime.
Table 2. Some analytical data and physical properties of the Schiff base ligand and its complexes
Found (calculated), %
H
Molecular
weight
Yield,
%
Compound
HL
Formula
Color
mp, °C
C
N
C19H18N4O2CI2
405.2
498.2
461.9
468.6
466.8
Orange
Red
145a
215
225a
157
105
62
70
60
55
64
56.20 (56.31)
45.75 (45.80)
49.35 (49.40)
48.65 (48.69)
48.85 (48.89)
4.40 (4.48)
4.00 (4.05)
3.45 (3.49)
3.32 (3.44)
3.40 (3.45)
14.13 (13.82)
[CoL2]·2H2O C19H20Cl2CoN4O4
11.12 (11.25)
12.05 (12.13)
11.75 (11.95)
11.81 (12.00)
[NiL2]
[ZnL2]
[CuL2]
C19H16N4O2CI2Ni
C19H16N4O2CI2Zn
C19H16N4O2CI2Cu
Green
Yellow
Dark-green
a Decomposition points of corresponding molecules.
complexes are in the range 0 to 56 Ω–1 cm2 mol–1 in
10–3 M DMF solutions indicating the non-electrolytic
nature of these compounds [14].
Electronic Spectra
The electronic absorption spectral data of the free
ligand and its complexes are given in Table 3. In the
spectra of the Schiff base ligand bands at 238–273 nm
are attributed to the benzene π–π* transitions [12, 13].
The bands at 314–336 nm are assigned to the imine
π–π* transition. Compared to the free ligand, the imine
π–π* transitions of the complexes were shifted to some
extent, because the imine nitrogen is involved in
coordination with the metal ion.
NMR Spectra of the Schiff Bases
In order to understand the solution structure of the
1
free Schiff base ligand, H NMR spectra have been
1
employed. The H NMR assignments are listed in
Table 4. The doublet-doublet observed at 7.60–7.20 ppm
(J 8.65 Hz) is assigned to the aromatic ring proton of
the ligand HL. The singlets at 8.20 and 12.50 ppm Are
assigned to the protons of CH and the proton and of
the oxime group, respectively. The multiplets at 3.40
ppm and 3.00 ppm are assigned to protons of
methylene groups.
Conductance Measurements
The molar conductance values of the synthesized
schiff base ligand and its Ni(II), Co(II), Cu(II) and Zn(II)
Table 3. Magnetic moments and electronic spectral data of
the ligand and its metal complexes
MS Studies
In the MS spectra of the ligand HL, m/e 405 [M+, 5%],
Compound
HL
μeff
λmax, nm
343 [M+ – 2NOH, 10 %], 203 [M+ – C8H7N2O2Cl, 35%],
189 [M+ – C8H7N3O2Cl, 30%], 147
[M+
–
–
466, 332, 314, 273, 238 sh
C11H13N3O2Cl, 65%], 124 [C7H4Cl+, 100%].
[CoL2]·2H2O
4.12
650 sh, 394, 379, 367, 351,
324, 300, 244
Electrochemical Studies
[NiL2]
[CuL2]
[ZnL2]
Diamag
1.71
346, 315, 274, 246
The electrochemical behaviors of the H2L ligand
and the CuL, CoL, NiL and ZnL complexes were
examined by means of cyclic voltammetry in DMSO.
273, 241
Diamag
280, 270, 243
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 7 2008

1460
DEMIR et al.
Potential, V
Fig. 3 Cyclic voltammogram of CuL.
Fig. 2. Structure of metal complexes (M = Ni, Cu, Zn, Co).
A typical cyclic voltammogram of CuL is shown in
Fig. 3. But H2L and its other complexes have not redox peak.
noprophane, were obtained from Merck (KGaA,
Germany) and all of them were purified according to
literature [18].
The cyclic voltammogram of the Cu(II) complex
obtained in DMSO (Fig. 3) solution at room tempera-
ture shows a redox process corresponding to the
copper(II)/copper(III) couple at Epa = +1.11 V and the
associated cathodic peak at Epc = +0.90 V. This
couple is found to be quasi-reversible as the peak
separation between the anodic and cathodic potential is
very high. But the ratio between the anodic and
cathodic currents suggests that the process is simple
one-electron transfer, quasi-reversible process [15, 16, 17].
Physical Measurement
The carbon, hydrogen and nitrogen analyses were
obtained using a Carlo Erba 1106 auto elemental
analyzer. Jasco FT/IR–300 E Spectrometer was used
for characterisation. The electronic spectra in the 200-
800 nm range were recorded in DMF on a Shimadzu
UV-160A spectrophotometer. Conductivities were measu-
red in DMF using a LF 330/SET Conductivity
measuring were performed at 22°C. Magnetic
moments were measured by the Gouy method by using
Biological Activities
1
Hg[Co(SCN)4] as calibrant. The H-NMR spectra of
In the present study, the antibacterial activities of
compounds were determined and given Table 5. Com-
pound HL Cu and HL Co showed moderate inhibition
effect against all the tested bacteria while compound
HL Ni and HL Zn have inhibition effect against some
test bacteria. Especially compound HL Zn has highly
activity towards B. subtilis and B. cereus. Also, Table
5 showed that most of metal complexes show more
inhibition effect against tested bacteria than the free
ligand.
the ligand HL were recorded with a Bruker Avance-
500 NMR instrument .
Preparation of Schiff Base Ligand
The ligand was prepared according to literature [19,
20]. Isonitroso-p-chloroacetophenone 0.183 g (1 mmol)
dissolved in methanol (20 ml), was added with
constant stirring to a solution of 1,3-diaminoprophane
Table 4. The 1H NMR spectra of the Schiff base ligand
However there is increase in the antimicrobial
activity of these complexes as according to free ligand,
it could not reach the effectiveness of the conventional
reference antibiotics.
δ, ppm
3.00
Peak
2(H)
4(H)
8(H)
2(H)
2(H)
Assignment
CH2 group
3.40
CH2 groups
EXPERIMENTAL
7.20–7.60
8.20
Aromatic ring (H)
CH (aldoxime)proton
OH
Material
Ni(CH3COO)2, Co(CH3COO)2, Cu(CH3COO)2 and
Zn(CH3COO)2 and p-chloroacetophenone, 1,3-diami-
12.50
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 7 2008

SYNTHESIS, ELECTROCHEMICAL, AND ANTIBACTERIAL ACTIVITY
Table 5. Inhibition values diameters of compounds against to the test bacteria
1461
Inhibition values (mm)
Compound
Staphylococcus
aureus ATCC
25923
Bacillus
megaterium RSKK
Staphylococcus
epidermidis Mu
Escherichia coli
ATCC 35218
Bacillus subtilis Bacillus cereus
RSKK 244
RSKK 863
5117
–
30
7
HL (Ligand)
HL (Ni)
–
–
–
6
6
9
–
8
–
6
–
8
HL (Cu)
8
9
9
9
HL (Co)
7
8
7
7
7
8
HL (Zn)
–
–
–
13
33
29
24
26
34
24
13
27
29
18
–
–
Tetracycline
Penicilin
25
20
21
–
34
25
30
23
34
25
24
31
17
15
29
26
–
–
Vancomisin
Cefepime
Ofloxacin
Ampicilin
–
18
9
–
25
33
24
–
(HL) 0.037 g (0.5 mmol) in methanol (10 ml). The
mixture was allowed to stirrer magnetically at 50°C
during 4.5 h. After cooling to room temperature, the
resulting precipitate was filtered and recrystalized by
hexane/methanol (1 : 1) .
oxygen by bubbling nitrogen for 15 min. and then
blanketed with the same gas during the experiments.
All compounds were investigated at 25°C.The voltam-
mograms were recorded with a potential scan of
100 mV s–1.
Biological Activity
Preparation of Complexes
Antibacterial activity of compounds was
determined by the disc diffusion method [22]. The
antimicrobial screening was performed using Mueller-
Hinton Agar. The culture suspensions were prepared
and adjusted by comparing against 0.5 Mc Farland
turbidity standard tubes.
All of the complexes were synthesized by the
reaction of the Schiff base ligand (1 mmol, in 20 ml
methanol) with the corresponding metal salts (0.5 mmol,
10 ml methanol) at 50°C during 2 h. The resulting
precipitate was filtered, washed several times with
methanol and dried over calcium chloride under
vacuum [21].
Muller-Hinton Agar (20 ml) was poured into each
sterile petri dish after injecting cultures (100 µl) of
microorganisms and distributing medium in Petri dish
homogeneously. Compounds were filtered with a pore
size of 0.45 µm. All of the compounds were dissolved
in DMSO of 5 mg ml–1. Empty sterilized discs of 6 mm
(Whatman No: 1) were each impregnated with 50 ml
of compounds. Discs were placed on agar plates, and
the plates were incubated at 37°C for 24 h. Inhibition
zones formed on the medium were evaluated in mm.
The solvent control (DMSO) did not show any
Electrochemical Study
The cyclic voltammetry experiments were carried
out with a three electrode apparatus using a CHI600A
electrochemical workstation (Covarda, USA), the
working electrode was a Platinum foil, Ag/Ag+ and Pt
wire were used as reference and counter electrodes,
respectively. The H2L and complexes solutions (1.0 ×
10–3 mol l–1) in DMSO, with Lithium perchlorate
(0.1 mol l–1) as supporting electrolyte were purged of
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 7 2008

1462
DEMIR et al.
Choi, Y.K., Journal of Power Sources, 2002, vol. 112,
p. 76.
11. Tarek Ismail, M.A., J. of Coord. Chem., 2006, vol. 59,
no. 3.
12. Casella, L., Gullotti, M., and Pacchioni, G., J. Am.
Chem. Soc., 1982, vol. 104, p. 2386.
13. Deiztsch, V., Strauch, P., and Hoyer, E., Coord. Chem.
Rev., 1992, vol. 121, p. 43.
antimicrobial activity. Studies performed in duplicate
and the inhibition zones were compared with those of
reference discs. Reference discs used for control are as
follows: Tetracycline (30 µg), Penicilin (10 µg),
Vancomisin (30 µg), Cefepime (30 µg), Ofloxacin (5 µg),
Ampicilin (10 µg).
REFERENCES
14. Demır, I., Akkaya, M., Bayrakcı, M., and Pekacar, A.I.,
Asian Journal of Chemistry, 2007, vol. 19, no. 5, p. 3954.
15. Shirin, Z. and Mukherjee, R.M., Polyhedron, 1992, vol. 11,
p. 2625.
1. Chakravorty, A., Coordination Chem. Rev., 1974, no. 13,
p. 1.
2. Tschugaeff, L., Ber. Deutsch. Chem. Ges., 1907, no. 40,
p. 3498.
16. Shyamala, A. and Chakravarty, A.R., Polyhedron, 1993,
vol. 12, p. 1545.
3. Metal Complexes May be Better Anticancer Drugs,
1982, Chem. Eng. News, 19 April, p. 36
4. Deveci, M.A., PhD Thesis, 1994, Selçuk University,
Konya-TR.
17. Raman, N., Muthuraj, V., Ravıchandran, S., and Kula-
ndaısamy, A., Proc. Indian Acad. Sci. (Chem. Sci.),
2003, no. 115, p. 161.
18. Casey, M., Leonard, J., Lygo, B., and Proccto, G.,
Advanced Practical Organic Chemistry, Blackie
Academic & Professional, 1993, Chp. 4, p. 28.
19. Ibrahim Demir and İhsan Pekacar, A., Synthesis and
Reactivity in Inorganic, Metal-Organic and Nano-Metal
Chemistry, 2005, vol. 35, p. 825.
5. Ersoz, M., Yildiz, S., and Pehlivan, E., J. Chrom. Sci.
1993, vol. 31, p. 65.
6. Pekacar, A.İ., Mercimek, B., and Özcan, E., Synt. React.
Inorg. Met. Org. Chem., 1997, vol. 27(3), p. 455.
7. Mercimek, B., İrez G., Deveci, M.A., Bedük, A.D.,
Sarikavakli, N., and Uçan, H.İ., The Synthesis and Ni(II),
Co(II), Zn(II) And Cd(II) Complexes Of Two Novel
Tetraoximes, Macromolecular Reports, 1995, vol. A32,
no. 8, p. 1199.
20. Demır, I. and Pekacar A.I., Asian Journal of Chemistry
2007, vol. 19, no. 3, p. 1919.
21. Jian-Hao Zhou, Zheng Liu, Yi-Zhi Li, You Song, Xue-
Tai Chen, Xiao-Zeng You., J. of Coord. Chem., 2006,
vol. 59, no. 2.
8. Rastoh D.K. and Sharma, C.K., J. Inorg. Nucl. Chem.,
1974, vol. 36, p. 2219.
9. Hueso-Urena, F., Illan-Cabeza, N.A., Moreno-
Carretero, M.N., and Penas-Chamorro, A.L., Acta Chim
Slov. , 2000, vol. 47, p. 481.
22. NCCLS (National Committee for Clinical Laboratory
Standards), Performance Standards for Antimicrobial
Disk Susceptibility Test, 1997, 6th ed., Wayne PA:
Approved Standard. M2-A6.
10. Kim, W.S., Sim, W.J., Chung, K., Sung, Y.E., and
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