Synthesis, spectroscopic characterization, and genotoxicity of a new group of azo-oxime metal chelates

Article abstract of DOI:10.3906/kim-1210-57

A new azo-oxime ligand, 2-[(E)-(hydroxyimino)methyl]-4-[(E)-(4-nitrophenyl) diazenyl]phenol, (pxoxH₂) (2), was prepared by condensation of hydroxylamminehydrochloride and 2-hydroxy5-[(4-nitrophenyl)diazenyl]benzaldehyde (1) with treatment of a solution of diazonium salt of p-nitroaniline and 2-hydroxybenzaldehyde in ethanol. The 6 coordination compounds, [Mn(pxoxH) ₂ (H₂ O)₂ ].H₂O (3), [Co(pxoxH) ₂ (H2 O)₂ ].4H₂O (4), [Ni(pxoxH)₂ (H₂ O)₂ ].2H₂O (5), [Cu(pxoxH)₂ ].H₂O (6), [Zn(pxoxH)₂ ].6H2O (7), and [Cd(pxoxH) ₂ (H2 O)₂ ].H₂O (8), were prepared by reacting Mn(II), Ni(II) Cu(II), Co(II), Zn(II), and Cd(II) ions with the ligand. The structures of the compounds were elucidated from the elemental analysis data and spectroscopic studies. The azo-oxime metal complexes were also characterized by XRD, magnetic moment, molar conductivity, and thermal analyses. Elemental analyses of the chelates suggested that the metal to ligand ratio was 1:2. It was found that the ligand acts as a bidentate bending through the phenolic oxygen and nitrogen atom of the C=N-OH group similar to most oximes. Upon complexation with the ligand, the Cu(II) and Zn(II) ions formed square planar and tetrahedral structures, respectively, and the Mn(II), Ni(II), Co(II), and Cd(II) ions formed octahedral structures with 2 water molecules as axial ligands. Finally, the ligand and its complexes were assessed for their genotoxicity. TUeBITAK.

Full text of DOI:10.3906/kim-1210-57

Turk J Chem
Turkish Journal of Chemistry
(2013) 37: 422 – 438
¨
http://journals.tubitak.gov.tr/chem/
˙
c
⃝ TUBITAK
doi:10.3906/kim-1210-57
Research Article
Synthesis, spectroscopic characterization, and genotoxicity of a new group of
azo-oxime metal chelates
1
1
Beyza CABIR, Barı¸s AVAR,2 Mehmet GULCAN, Ahmet KAYRALDIZ,3
˙
¨
4,∗
˘
Mu¨kerrem KURTOGLU
1Department of Chemistry, Yu¨zu¨ncu¨ Yıl University, Van, Turkey
2
3
˙
Department of Physics, Kahramanmara¸s Su¨t¸cu¨ Imam University, Kahramanmara¸s, Turkey
˙
Department of Biology, Kahramanmara¸s Su¨t¸cu¨ Imam University, Kahramanmara¸s, Turkey
4
˙
Department of Chemistry, Kahramanmara¸s Su¨tc¸u¨ Imam University, Kahramanmara¸s, Turkey
Received: 29.10.2012
•
Accepted: 21.03.2013
•
Published Online: 10.06.2013
•
Printed: 08.07.2013
Abstract: A new azo-oxime ligand, 2-[(E)-(hydroxyimino)methyl]-4-[(E)-(4-nitrophenyl)diazenyl]phenol, (pxoxH2) (2),
was prepared by condensation of hydroxylamminehydrochloride and 2-hydroxy5-[(4-nitrophenyl)diazenyl]benzaldehyde
(1) with treatment of a solution of diazonium salt of p-nitroaniline and 2-hydroxybenzaldehyde in ethanol. The 6 co-
ordination compounds, [Mn(pxoxH)2 (H2 O)2 ].H2 O (3), [Co(pxoxH)2 (H2 O)2 ].4H2 O (4), [Ni(pxoxH)2 (H2 O)2 ].2H2 O
(5), [Cu(pxoxH)2 ].H2 O (6), [Zn(pxoxH)2 ].6H2 O (7), and [Cd(pxoxH)2 (H2 O)2 ].H2 O (8), were prepared by reacting
Mn(II), Ni(II) Cu(II), Co(II), Zn(II), and Cd(II) ions with the ligand. The structures of the compounds were elucidated
from the elemental analysis data and spectroscopic studies. The azo-oxime metal complexes were also characterized by
XRD, magnetic moment, molar conductivity, and thermal analyses. Elemental analyses of the chelates suggested that
the metal to ligand ratio was 1:2. It was found that the ligand acts as a bidentate bending through the phenolic oxygen
and nitrogen atom of the C=N-OH group similar to most oximes. Upon complexation with the ligand, the Cu(II) and
Zn(II) ions formed square planar and tetrahedral structures, respectively, and the Mn(II), Ni(II), Co(II), and Cd(II) ions
formed octahedral structures with 2 water molecules as axial ligands. Finally, the ligand and its complexes were assessed
for their genotoxicity.
Key words: Synthesis, spectroscopy, phenolic oxime, metal complex, X-ray powder diffraction, genotoxicity
1. Introduction
Transition metal complexes show good thermal, optical, and chemical properties. Therefore, they are widely used
in applications such as optical data storage, photoswitching, nonlinear optics and photochromic materials, dyes,
chemical analysis, and pharmaceuticals.1−6 The synthesis and properties of new transition metal complexes
have been widely investigated owing to their possible applications in a variety of fields.
Azo-oximes are a class of compounds possessing both azo and hydroxyimino groups. One of the major
characteristics of azo dyes is the presence of one or more azo (-N=N-) groups. These compounds can be regarded
as the largest class of industrially synthesized organic dyes due to their versatile application in various fields
such as textile dyes, biomedical applications, advanced application in organic synthesis, lasers, liquid crystalline
displays, electro-optical devices, and ink-jet printers.7−9
∗Correspondence: mkurtoglu@ksu.edu.tr
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The hydroxyimino groups are good donors and can form stable complexes with transition metal ions.
The oximes and their metal complexes have a significant role in the development of inorganic chemistry.
They have been widely studied coordination compounds used in a variety of biochemical10,11 and analytical
applications.12,13 They have also attracted attention due to their possible antimicrobial applications.14,15 The
ortho-hydroxy-aryloximes act as excellent bidentate ligands through the nitrogen and oxygen donor atoms.
Their metal complexes are well-recognized extractants that find industrial applications in extractive metallurgy
and separation science.16,17
The assessment of genotoxicity is a mandatory preliminary step in the safety assessment of newly
synthesized chemicals including pharmaceuticals, food additives, and industrial substances.18−20 The bacterial
Ames test developed by Dr Bruce Ames in 197521 is commonly used for possible genotoxic effects of chemical
compounds (ability to induce a mutation or cancer). The assay performed in Salmonella Typhimurium is less
expensive and gives faster results compared to standard tests for carcinogenicity in animals.22,23 The test strains
of S . Typhimurium (TA 98 and TA 100) that possess different types of mutations in the histidine operon are
used in the test for identifying reverse mutation.
In our previous studies, we investigated the synthesis and characterization of various new monodentate
and bidentate ligands.24−27 In the present study, the synthesis and characterization of Mn(II), Ni(II), Cu(II),
Co(II), Zn(II), and Cd(II) complexes of a new azo-oxime ligand (pxoxH2) are reported (Figure 1). The X-ray
diffraction studies on the manganese(II) and cadmium(II) complexes are described. Both the new oxime ligand
linked 4-nitrophenylazo and its metal complexes were also screened for their genotoxicity.
H
O
N
+
N
NH2
-
OH
N
O
O
i
ii
+
N
N
+
+
N
-
N
iii
-
O
O
O
O
-
O
+
N
N
OH
N
N
O
OH
H
i: NaNO2/HCl; ii: salicylaldehyde, iii: H2NOH.HCl
Figure 1. Synthesis reaction of 2-[(E)-(hydroxyimino)methyl]-4-[(E)-(4-nitrophenyl)diazenyl]phenol ligand.
2. Experimental
2.1. Materials
p-Nitroanilin, salicylaldehyde, and hydroxylamminehydrochloride were purchased from Aldrich. MnCl2 ,
NiCl2 .6H2 O, CuCl2 .2H2 O, CoCl2 .6H2 O, ZnCl2 , and CdCl2 (Merck) were used as purchased with no addi-
tional purification. All solvents were reagent grade and used without further purification.
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2.2. Physical measurements
The microanalysis of carbon, hydrogen, and nitrogen was performed with a LECO CHNS 932 elemental
analyzer. The 1 H NMR spectrum of the azo-oxime ligand was obtained in deuterated DMSO as solvent
on a Bruker FT-NMR AC-400 (300 MHz) spectrometer. All chemical shifts were reported in δ (ppm) relative
to the tetramethylsilane as an internal standard. Infrared spectra (KBr disk) were recorded in the 4000–400
cm−1 range on a Shimadzu 8300 FT-IR spectrometer. The UV/Vis spectra were obtained on a Shimadzu
160A UV spectrometer. The X-ray powder diffraction analysis was performed by a Philips X’Pert PRO X-ray
diffractometer using Cu–Kα radiation with the wavelength of 0.154 nm at 40 kV and 30 mA. The measurements
were obtained by scanning at diffraction angles (2θ) in the range of 10◦ to 50◦ at room temperature. The
phase identification was performed using X’Pert High Score software using the ICDD-PDF 2 database. Melting
points were obtained with an Electrothermal LDT 9200 apparatus in open capillaries. Magnetic measurements
were obtained by the Gouy method using Hg[Co(SCN)4 ] as a calibrant. Molar conductance of the transition
metal complexes was determined in DMF at room temperature by using an IQ Scientific Instruments Multimeter.
Thermal gravimetric analysis (TGA) measurements were obtained by a PerkinElmer Diamond thermal analyzer.
2.3. Synthesis of 2-hydroxy5-[(4-nitrophenyl)diazenyl]benzaldehyde (px)(1)
The azo-coupled 2-hydroxybenzaldehyde was synthesized using the known coupling methods.28 2-Hydroxyben-
zaldehyde (1.22 g, 10 mmol) was dissolved in distilled water (30 mL) containing 0.7 g (8.8 mmol) of sodium
hydroxide and 40 mmol of sodium carbonate over 30 min at 0 ◦ C. The resulting solution was added slowly
to the solution of diazonium chloride of 1.38 g (10 mmol) of p-nitroanilin in water at 0–5 ◦ C. The reaction
mixture was stirred for 1 h at 0 ◦ C and then allowed to warm slowly to room temperature. The product was
collected by filtration and washed with 100 mL of NaCl solution (10%) under vacuum. The obtained yellowish
orange solid was dried under vacuum at 80 ◦ C overnight.
2.4. Synthesis of 2-[(E)-(hydroxyimino)methyl]-4-[(E)-(4-nitrophenyll)diazenyl]phenol (pxoxH2)
(2)
The azo-oxime compound was prepared according to the following method. NH2 OH.HCl (0.111 g, 16 mmol)
and 2-hydroxy-5-[(E)-phenyldiazenyl] benzaldehyde (0.254 g, 10 mmol) were dissolved in 30 mL of EtOH with
NaOH (0.2 g, 50 mmol) in EtOH. The solution was refluxed for 1 h and then left at room temperature. After
cooling, the azo-oxime ligand was obtained as orange crystals. The crystals were filtered, washed with 20 mL of
cold EtOH, and then dried under vacuum at 80 ◦ C overnight. Yield: 2.10 g (73%). Mp: 226–227 ◦ C. Elemental
analysis for C13 H10 N4 O4 (286.24 g/mol): Calcld. (%): C, 54.56; H, 3.50; N, 19.58. Found (%): C, 54.30; H,
3.50; N, 19.26. Selected IR bands (KBr, cm−1): 3371 (O-H), 3040 (Ar-C-H), 1619 (C=N), 1516 (C-C), 1489
(N=N), 1104 (N-O). 13 C NMR (δ) 160.5, 155.8, 148.5, 146.7, 146.0, 128, 126, 124.2, 123.4, 120.6, 117.5.
2.5. Synthesis of [Mn(pxoxH)2 (H2 O)2 ].H2 O (3)
A solution of MnCl2 (0.010 g, 0.07 mmol) in 5 mL of hot EtOH was added to a solution of pxoxH2 (0.040 g,
0.14 mmol) in 10 mL of hot MeOH. After the addition, the pH of the solution fell to 3.5 and was adjusted with
0.1 N NaOH in EtOH to 4.5–5.0 where the precipitation of the complex started. The mixture was then heated
in a water bath for another 2 h to complete the precipitation. The dark red complex obtained was filtered,
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washed with cold EtOH, and dried under vacuum. Yield: 0.041 g (50%). Mp: 238–239 ◦ C. Elemental analyses
for C26 H22 N8 MnO10 (663.44 g/mol): Calcld. (%): C, 47.07; H, 3.34; N, 16.89. Found (%): C, 47.87; H, 3.70;
N, 16.49. Selected IR bands (KBr, cm−1): 3586 and 3370 (O-H), 3103 (Ar-C-H), 1611 (C=N), 1517 (C-C),
1489 (N=N), 1104 (N-O), 860 (M-OH2), 508 (Mn-O), 480 (Mn-N). µeff (BM): 5.05. Λo (S cm2 mol−1):
25.06.
2.6. Synthesis of [Co(pxoxH)2 (H2 O)2 ].4H2 O (4)
A solution of CoCl2 .6H2 O (0.029 g, 0.12 mmol) in 20 mL of MeOH was added to a magnetically stirred 15-mL
MeOH solution containing the ligand (0.07 g, 0.24 mmol) at 70 ◦ C. The obtained solution was left at room
temperature. The cobalt(II) complex was obtained as dark red precipitates. The brown product was filtered,
washed with EtOH, and then dried under vacuum. Yield: 0.088 g (60%). Mp: 234–235 ◦ C. Elemental analyses
for C26 H30 N8 CoO14 (739.50 g/mol): Calcld. (%): C, 42.20; H, 4.08; N, 15.15. Found (%): C, 42.30; H, 3.82;
N, 15.19. Selected IR bands (KBr, cm−1): 3370 (O-H), 3072 (Ar-C-H), 1612 (C=N), 1516 (C-C), 1488 (N=N),
1103 (N-O), 854 (M-OH2), 501 (Co-O), 476 (Co-N). µeff (BM): 3.73. Λo (S cm2 mol−1): 12.75.
2.7. Synthesis of [Ni(pxoxH)2 (H2 O)2 ].2H2 O (5)
A methanolic solution (30 mL) of NiCl2 .6H2 O (0.042 g, 0.174 mmol) was added to 50 mL of a clear solution
of pxoxH2 (0.1 g, 0.35 mmol). The resulting mixture was refluxed for 1 h in a water bath. The volume
was reduced by half via slow evaporation. After cooling, the precipitated reddish-brown crystals were filtered,
washed several times with EtOH and MeOH, and dried under vacuum. Yield: 0.121 g (58%). Mp: 258–259 ◦ C.
Elemental analysis for C26 H26 N8 NiO12 (703.23 g/mol): Calcld. (%): C, 44.40; H, 3.72; N, 15.93. Found (%):
C, 44.42; H, 3.67; N, 15.80. Selected IR (KBr, cm−1): 3367 (O-H), 3090 (Ar-C-H), 1609 (C=N), 1510 (C-C),
1488 (N=N), 1103 (N-O), 854 (M-OH2), 503 (Ni-O), 475 (Ni-N). µeff (BM): 2.62. Λo (S cm2 mol−1): 22.20.
2.8. Synthesis of [Cu(pxoxH)2 ].H2 O (6)
Copper(II)chloride hexahydrate (0.024 g, 0.174 mmol) dissolved in MeOH (15 mL) was added to a hot solution
of the azo-oxime ligand (0.1 g, 0.35 mmol)) dissolved in MeOH (20 mL). The resulting solution was stirred and
heated on a hot plate at 70–80 ◦ C for 1 h. The volume of the obtained solution was reduced to one-half by
evaporation. One day later, the brown solid of the complex formed was filtered, the solid was washed with cold
EtOH, and finally it was dried under vacuum. Yield: 0.1159 g (55%). Mp: >300 ◦ C. Elemental analysis for
C26 H20 N8 CuO9 (657.04 g/mol): Calcld. (%): C, 47.53; H, 3.07; N, 17.05. Found (%): C, 47.34; H, 2.99; N,
17.87. Selected IR bands (KBr, cm−1): 3399 and 3242 (O-H), 3060 (Ar-C-H), 1613 (C=N), 1522 (C-C), 1478
(N=N), 1110 (N-O), 498 (Cu-O), 480 (Cu-N). µeff (BM): 1.89. Λo (S cm2 mol−1): 13.54.
2.9. Synthesis of [Zn(pxoxH)2 ].6H2 O (7)
Zinc(II) chloride (0.0167 g, 0.122 mmol) was dissolved in 10 mL of EtOH. To this solution, a 30 mL of
MeOH solution containing pxoxH2 (2) (0.07 g, 0.25 mmol) was added. The mixture was stirred for 2 h
at room temperature and refluxed for another 2 h. The precipitated black compound was filtered, washed
with cold EtOH, and dried under vacuum. Yield: 0.0885 g (60%). Mp: 201–202 ◦ C. Elemental analyses for
C26 H30 N8 ZnO14 (745.96 g/mol): Calcld. (%): C, 41.86; H, 4.05; N, 15.02. Found (%): C, 41.35; H, 3.65; N,
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14.53. Selected IR bands (KBr, cm−1): 3475 and 3368 (O-H), 3103 (Ar-C-H), 1612 (C=N), 1517 (C-C), 1489
(N=N), 1104 (N-O), 510 (Zn-O), 482 (Zn-N). µeff (BM): Dia. Λo (S cm2 mol−1): 16.13.
2.10. Synthesis of [Cd(pxoxH)2 (H2 O)2 ].H2 O (8)
CdCl2 (0.0134 g, 0.07 mmol) in 10 mL of MeOH solution was slowly added to a constantly stirring solution
of pxoxH2 (2) (0.042 g (0.15 mmol) in 20 mL of MeOH. The color of the solution turned dark brown. The
reaction mixture was kept stirring at 70–80 ◦ C until the precipitation was completed. Then it was brought to
room temperature and the brown crystalline complex was precipitated. The product was filtered, washed with
water and EtOH, and finally dried under vacuum. The obtained compound was soluble in DMF and DMSO.
Yield: 0.045 g (47%). Mp: 248–249 ◦ C. Elemental analyses for C26 H20 N8 CdO9 (702.90 g/mol): Calcld. (%):
C, 44.42; H, 2.86; N, 15.94. Found (%): C, 44.06; H, 3.12; N, 15.12. Selected IR bands (KBr, cm−1): 3453 and
3366 (O-H), 3073 (Ar-C-H), 1612 (C=N), 1515 (C-C), 1488 (-N=N-), 1106 (N-O), 853 (M-OH2), 502 (Cd-O),
474 (Cd-N). µeff (BM): Dia. Λo (S cm2 mol−1): 17.63.
2.11. Ames test
The reagents including medium, buffers, and the S9-mix used in the Ames test were prepared as described in the
study by Kayraldiz et al.29 Histidine-deficient S. Typhimurium strains TA98 and TA100 were provided by JL
Swezey (Microbial Genomics and Bioprocessing Research Unit, North University, Illinois, USA). Dimethyl sul-
foxide (DMSO) suspensions of 2-aminofluerene (2-AF) and 4-nitro-o-phenylenediamine (NPD) as well as sodium
azide (dissolved in distilled water) were used as positive controls. The test reagents were suspended in DMSO
(px, pxoxH2 , [Zn(pxoxH)2 ].6H2 O, [Co(pxoxH)2 (H2 O)2 ].4H2 O, [Mn(pxoxH)2 (H2 O)2 ].H2 O, [Cd(pxoxH)2
(H2 O)2 ].H2 O) with the final concentrations of 1.25, 0.75, 0.50, and 0.25 mg/plate for the mutagenicity test.
The final concentrations, i.e. 0.62, 0.49, 0.37, 0.24, and 0.12 mg/plate of [Ni(pxoxH)2 (H2 O)2 ].2H2 O and 0.31,
0.24, 0.18, 0.12, and 0.06 mg/plate of [Cu(pxoxH)2 ].H2 O, suspended in DMSO were used for the mutagenicity
test.
The standard procedure for the plate-incorporation assay was carried out using TA98 and TA100 strains
for determination of the frame-shift mutations and base-pair substitution mutations, respectively. Using both of
the strains, the Ames test was performed with metabolic activation (+S9 mix) to obtain a first approximation
of mammalian metabolism, and without metabolic activation (–S9 mix). The assay was carried out according to
Maron and Ames.30 TA98 and TA100 strains were exposed to a range of concentrations of each test compound
in a soft agar overlay. The number of revertants observed in each concentration of the test substances and
the spontaneous control was scored. The observed differences between the test compounds and control were
analyzed by t-test (Minitab V14). Regression and correlation tests were used for dose–response relationships.
3. Results and discussion
3.1. Synthesis and solubility of the metal chelates
The azo-oxime ligand 2-[(E)-(hydroxyimino)methyl]-4-[(E)-(4-nitrophenyll)diazenyl]phenol (pxoxH2) (2) was
prepared by reacting 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde (1) with hydroxylamminehydrochloride
(Figure 1). The new azo-oxime ligand, 2-[(E)-(hydroxyimino)methyl]-4-[(E)-(4-nitrophenyll)diazenyl]phenol
(pxoxH2), formed mononuclear complexes (Figure 2) with Ni(II), Co(II), Cu(II), Zn(II), and Cd(II) as follows:
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2 pxoxH2+ MX2 → [M(pxoxH)2 .(H2 O)m ].nH2 O + 2HX
pxoxH2 : 2-[(E)-(hydroxyimino)methyl]-4-[(E)-(4-nitrophenyll)diazenyl]phenol.
M = Mn(II), m = 2, n = 1); Ni(II), m = 2, n = 2); Cu(II), m = 0, n = 2);
Co(II), m = 2, n = 4); Cd(II), m = 2, n = 2); Zn(II), m = 0, n = 6) and X = Cl.
O
O
+
N
N
HO
-
N
O
N
O
.nH2O
M
-
N
N
O
+
OH
N
N
O
M = Mn(II)(OH2)2(n = 1); Ni(II)(OH2)2)(n = 2); Cu(II) (n = 2); Co(II)(OH2)2 (n = 4);
Cd(II)(OH2)2(n = 2); Zn(II)(n = 6).
Figure 2. The proposed structure of the metal complexes.
The structures of the synthesized compounds were elucidated using a number of analytical methods
and spectroscopic techniques. The level of impurity in the product was checked with thin layer chromatog-
raphy (TLC). All of the metal complexes, [Mn(pxoxH)2 (H2 O)2 ].H2 O (3), [Co(pxoxH)2 (H2 O)2 ].4H2 O (4),
[Ni(pxoxH)2 (H2 O)2 ].2H2 O (5), [Cu(pxoxH)2 ].H2 O (6), [Zn(pxoxH)2 ].6H2 O (7), and [Cd(pxoxH)2 (H2 O)2 ].
H2 O (8), are stable in air, soluble in DMSO, and insoluble in common organic solvents. The single crystals of
the compounds could not be isolated from any organic solution; thus no definite structures could be described.
However, the analytical and spectroscopic data enable us to predict possible structures as shown in Figures 1
and 2.
The results of the elemental analyses of the azo-oxime ligand and its metal chelates are in good agreement
with the theoretical expectations. The elemental analyses of the coordination compounds indicate that the
metal–ligand ratios are 1:2 in all the metal complexes. The molar conductivities of the metal chelates in DMF
at 25 ◦ C are in the range of 12.75–25.06 Ω−1 cm2 mol−1 , indicating nonelectrolytes.31
3.2. 1 H and 13 C NMR spectra
The 1 H NMR data were obtained from the pxoxH2 compound in DMSO-d6 and peak assignments are provided
in Table 1. The 1 H NMR spectrum of pxoxH2 (2) in DMSO-d6 exhibited 2 singlet peaks at 11.55 and 11.15
ppm, which were attributed to -OH (N9 -) and -OH (C7 -), respectively. The -OH (C10 -) and -OH (C7 -) signals
disappeared in D2 O, indicating an acidic nature. The 1 H NMR spectrum of the azo-oxime ligand is shown in
Figure 3. The spectrum of the pxoxH2 (2) showed a singlet peak at 10.38 ppm due to the presence of hydrogen
of the azomethine group (C8 H=N). The peaks observed in the range of 7.14–7.25 and 7.93–7.94 ppm in 1 H
NMR spectrum of pxoxH2 (2) were attributed to the aromatic protons.26−28 The 13 C NMR data were obtained
from the pxoxH2 compound in DMSO-d6 . The 13 C NMR spectrum displayed characteristic signals at 160.5
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and 155.8 ppm due to the Ar-C-OH and -C-N=N of the ligand, respectively. The peaks at 148.5 and 146.7
ppm were attributed to azomethine and C-NO2 carbons of the ligand, respectively. On the other hand, the
spectrum of the ligand showed peaks in the region δ 117.5–146.0 ppm, due to the presence of aromatic carbons.
Table 1. 1 H NMR data of the ligand pxoxH2 in DMSO-d6 .
OH
10
8
14
15
16
17
-
O
21
N
9
3
13
+
N
12
N
19
2
1
OH
7
N
11
O
20
4
18
5
6
Chemical shifts, δT MS (ppm) Assignmentsa
11.55
11.15
10.38
7.94
7.93
7.25
[s, 1H] (10)
[s, 1H] (7)
[s, 1H] (8)
[d, 2H] (15,17)
[d, 2H] (14,18)
[s, 1H] (3)
7.22
7.14
[d, 1H] (5)
[d, 1H] (6)
as, singlet and d, doublet
Figure 3. 1 H NMR spectrum of the ligand (i: 1 H NMR spectrum; ii: deuterated-NMR).
3.3. Magnetic and electronic spectral studies
The UV/Vis spectra of phenylazo-linked azo-oxime ligand and its metal complexes were measured in DMF
at room temperature, and the absorbance maxima are presented in Table 2. The pxoxH2 ligand (2) was
characterized mainly by 4 absorption bands in the region of 36,363–24,691 cm−1 . The bands at 24,691 and
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28,571 cm−1 were assigned to n → π* transitions in the azo and hydroxyimine groups in the phenyl azo-
linked hydroxyimino ligand, pxoxH2 . The third and fourth bands, located at 33,333 and 36,363 cm−1 , can be
assigned to the moderate energy π → π* transition of the –N=N- and –CH=N- groups or aromatic rings. The
UV-visible spectrum of the pxoxH2 azo-oxime ligand in DMF solution is shown in Figure 4.
Table 2. Electronic spectral data for azo-oxime ligand and its metal complexes in DMF.
Absorbance, λmax (nm)(cm−1
π → π*, n → π* and charge
)
Band
assignment
No.
1
Compound
px
transfer transitions
315, 360, (31,746),
(27,777)
d → d transitions
–
–
275, 300, 350, 405,
(36,363), (33,333),
(28,571), (24,691)
2
pxoxH2
–
–
6A1g → T1g
4
275, 300, 350, 400,
(36,363), (33,333),
(28,571), (25,000)
470, 515, 590, 630,
(21,276), (19,417),
(16,949), (15,872)
485, 535, 585,
6A1g
→
4Eg
3
4
[Mn(pxoxH)2(H2O)2].H2O
[Co(pxoxH)2(H2O)2].4H2O
6A1g → Eg
4
6A1g
→
4T1g
4
275, 300, 350, 405, 445,
(36,363), (33,333),
(28,571), (24,691), (22,471)
4T1g → T1g
(20,619), (18,691), 4T1g
→
→
→
→
→
4A2g
4
(17,094)
4T1g
3A2g
3A2g
3A2g
T2g
3T1g
3T1g
290, 345, 360, (34,482),
(28,985), (27,777)
290, 345, 420, (34,482),
(28,985), (23,809)
275, 300, 350, 405, 470,
(36,363), (33,333),
(28,571), (24,691), (21,276)
275, 300, 350,
420, 485, 550,
(18,181)
550, 590, (18,181),
(16,949)
5
6
7
[Ni(pxoxH)2(H2O)2].2H2O
[Cu(pxoxH)2].H2O
3T2g
2
2B1g → Eg
2B1g → B2g
2
[Zn(pxoxH)2].6H2O
-
-
-
-
485, (36,363), (33,333),
(28,571), (24,691)
8
[Cd(pxoxH)2(H2O)2].H2O
The UV/Vis spectra can often provide quick and reliable information about the ligand arrangement in
metal complexes. The manganese(II) complex (3) displayed weak absorption bands in the range of 15,872–21,276
3
cm−1 . In the high-spin octahedrally coordinated Mn(II) complex, the lowest configuration (t2g
)
(eg)2 gives
6
rise to ground state A1g . Since this is the only sextet level present, all the absorption bands must therefore
be spin-forbidden transitions. The UV/Vis spectrum of the Mn(II) complex displayed weak absorption bands
at 15,872, 16,949, 19,417, and 21,276 cm−1 , which were characteristic of the octahedral geometry of this
6
6
6
complex. These bands may be assigned to A1g
→
4 T1g
,
6 A1g
→
4 Eg , A1g
→
4 T1g , and A1g
→
4 Eg transitions, respectively.32 The magnetic moment value for Mn(II) complex was 5.05 B.M., which is
in the expected range of octahedral geometry around the central metal ion.33,34 The electronic spectrum of
3
the [Ni(pxoxH)2 (H2 O)2 ].2H2 O (5) complex showed 2 well-defined bands assignable to A2g
3 A2g
→
3 T2g and
→
may be obscured by the more intense charge transfer band, was calculated theoretically and found to be at
3 T1g transitions in an octahedral structure, respectively. The third d–d transition band, which
35
23,809 cm−1
.
The observed magnetic moment of the Ni(II) complex was 2.62 B.M. The UV/Vis spectrum of
429

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CABIR et al./Turk J Chem
2
copper(II) complex showed 2 absorption bands at 16,949 and 18,181 cm−1 associated to B1g
→
2 B2g and
2 B1g 2 Eg transitions, respectively, indicating the possibility of having a square planar geometry of the
→
metal complex.36 The spectrum of Cu(II) complex in dimethylformamide solution is given in Figure 5. The
magnetic moment of Cu(II) complex was 1.89 B.M., indicating the presence of one unpaired electron.37
2
2.5
1.8
1.6
1.4
1.2
1
2
1.5
1
0.8
0.6
0.4
0.2
0
0.5
0
0
5 5 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0
0 5
4 6 9 0 2 3 5 6 8 9 1 2 4 5 7 8 0 1 3 4 6 7 9 0 2 3 5
3 7
0
2
1
2 2 2 2 2 2 3 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5 5 6 6 6 6
0
5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0
3 4 6 7 9 0 2 3 5 6 8 9 1 2 4 5 7 8 0 1 3 4 6 7 9 0 2 3 5
0
1
2 2 2 2 2 2 3 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5 5 6 6 6 6
2
λ
λ
Figure 4. UV-visible spectrum of the pxoxH2 ligand in
Figure 5. UV-visible spectrum of [Cu(pxoxH)2 ].H2 O
DMF.
complex in DMF.
The cobalt(II) complex exhibited 3 bands, which are expected from an octahedral structure.35 The
UV/Vis spectrum of the Co(II) complex displayed 2 well-defined spectral bands at 17,094 cm−1 and 20,619
4
cm−1 along with a shoulder at 18,691 cm−1 . These spectral bands may have corresponded to T1g
→
4 T2g
,
4 T1g
→
4 A2g , and T1g
→
around cobalt(II). The measured magnetic moment value (3.73 B.M.) of the Co(II) complex was lower than
4 T1g transitions, respectively, which are characteristic of 6-coordinated geometry
4
the spin-only value (3.87 B.M.) and also lower than the values reported for the complexes having octahedral
structures.38
The electronic absorption spectrum of Zn(II) complex showed 5 bands at 21,276, 24,691, 28,571, 33,333,
and 36,363 cm−1 , which were assigned to the charge transfer, n → π* and π → π* transitions, respectively. The
bands at 24,691, 28,571, 33,333, and 36,363 cm−1 in the UV-visible spectrum of the [Cd(pxoxH)2 (H2 O)2 ].H2 O
complex (8) can be related to n → π∗ (-N=N-), n → π∗ (-CH=N-), π → π* (-N=N-), and π → π* (-CH=N-)
or aromatic ring transitions, respectively. The spectroscopic data are given in Table 2.
3.4. Infrared spectra
The IR measurements of the pxoxH2 azo-oxime ligand (2) and its metal complexes were obtained in the range
4000–400 cm−1 . The characteristic IR bands of the pxoxH2 ligand and its metal chelates were explained in
the experimental section. Generally, the oxime compounds can be characterized by 3 IR absorption bands at
3700–3200 cm−1 (O–H str), 1615–1650 cm−1 (C=N str), and 1100–950 cm−1 (N–O str).15
The strong and broad band appearing at 3371 cm−1 in the spectrum of the azo-oxime ligand was assigned
to the vibrations of the hydroxyl groups belonging to the hydroxyimino (-C=N-OH) and phenolic groups (Ar-
OH) in the structure.39 The vibration spectrum of the bidentate ligand is shown in Figure 6. Although we know
that the coordinated water and the lattice water are present in the crystal structure and can give vibrational
bands at different regions in the infrared spectrum, the hydroxyl vibration bands coming from the hydroxyimino
430

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CABIR et al./Turk J Chem
group and coordinated or latticed water in the structure were observed as combined strong and broad bands
between 3586 and 3242 cm−1 . The infrared spectra of the Mn(II), Ni(II), Co(II), and Zn(II) metal complexes
exhibited a broad band at 3586–3242 cm−1 , which was attributed to v(OH) associated water molecules, while
the band observed at approximately 860–853 cm−1 was assigned to coordinated water molecules.40
The absence of a sharp band at around 1657 cm−1 , which is related to the azo-aldehyde (azo-coupled 2-
hydroxybenzaldehyde) (1), supports the proposed structure. However, the band that appeared at 1619 cm−1 on
the spectrum of the ligand belongs to the azomethine moiety. Thus, we can conclude that the proposed structure
is in agreement with the spectral data. It is also common knowledge that the ν (C=N) stretching vibrations
are affected by complexation and are positioned at a frequency significantly different than the frequency of
ligand. The coordination of the azo-oxime ligand to the metal center through the nitrogen atom is expected
to reduce the electron density in the azomethine link and shift to lower ν (C=N) absorption frequency. In the
synthesized metal complexes, we observed the ν (C=N) stretching shifted to the lower frequencies and appeared
between 1613 and 1609 cm−1 , indicating the coordination of the azomethine nitrogen to the metal ions. The
IR spectrum of the copper(II) complex is given in Figure 7.
106.2
108.7
105
104
102
100
100
95
98
90
85
80
75
70
65
60
55
50
96
94
92
90
88
86
84
82
80
78
%T
%T
75.4
47.8
4400.0 4000
3000
2000
cm–1
1500
1000
450.0
4400.0 4000
3000
2000
cm–1
1500
1000
450.0
Figure 6. IR spectrum of the pxoxH2 ligand (KBr,
cm−1).
Figure 7. IR spectrum of [Cu(pxoxH)2 ].H2 O complex
(KBr, cm−1).
The stretching vibration bands belonging to ν (Ar-C-H), ν (C=N), ν (C-C), ν (N=N), and ν (N-O)
functional groups appeared in the spectrum of the ligand at 3040, 1619, 1516, 1489, and 1104 cm−1 frequencies,
respectively.
In the metal complexes, the aromatic C-H stretching bands were observed between 3103 and 3072 cm−1
.
The vibration band of the azo chromogen group both in the ligand and the complexes was seen at around 1484
cm−1 . Although the azo chromogen group has a donor character and can form coordination compounds, the
constant value of its vibration both in the ligand and the complexes shows that there is no coordination between
the azo chromogen group and the metal ions. On the other hand, there were 2 new bands, which were not
seen in the spectrum of the ligand, appearing also in the spectra of the complexes; the first one was the M-O
stretching bands seen at 510–498 cm−1 , which showed that the ligand was coordinated with the metals through
the phenolic hydroxyls, and the second weak band was M-N vibrations seen between 482 and 474 cm−1 . These
values are in good agreement with the values reported in the literature.15,26b
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CABIR et al./Turk J Chem
3.5. X-ray powder diffraction analysis
We attempted to prepare single crystals of the ligand and metal complexes from different solvents, but were
unsuccessful. However, the crystalline nature of Cd(II) and Mn(II) metal complexes can be readily evidenced
from their X-ray powder patterns. The X-ray powder diffractograms of the [Cd(pxoxH)2 (H2 O)2 ].H2 O and
[Mn(pxoxH)2 (H2 O)2 ].H2 O metal complexes were recorded using Cu–Kα as the source in the 2θ range 10–50◦ .
The X-ray powder diffraction patterns of the Cd(II) and Mn(II) complexes are given in Figure 8.
3
1
4
6
(b)
5
2
8
7
5
2
4
(a)
12
1
6
8
9
3
7
10
13
11
10
20
30
40
50
2 "eta [Degree]
Figure 8. X-ray powder diffraction patterns for the metal complexes; (a) [Cd(pxoxH)2 (H2 O)2 ].H2 O, (b) [Mn(pxoxH)2
(H2 O)2 ].H2 O.
The observed and calculated diffraction data of the Cd(II) and Mn(II) complexes are given in Tables 3
and 4, respectively. The XRD spectrum shows 13 reflections for Cd(II) complex with maxima at 2θ = 25.98◦
◦
˚
and d = 3.42 A, and 8 reflections for Mn(II) complex with maxima at 2θ = 25.91 and d = 3.43 A. All of
˚
the main peaks were indexed and their d-spacing and sin2θvalues were compared with the calculated ones.
The comparison of the values reveals that there is good agreement between calculated and observed values of
d-spacing and sin2θ. The parameters of unit cell for each sample were calculated by trial and error methods
as follows: the observed values were well fitted with the monoclinic system with the cell parameters, for Cd(II)
◦
˚
complex a = 17.20094 A, b = 7.43588 A, c = 7.85396 A, β = 110.58710 , and cell volume V = 940.40070
˚
˚
3
◦
˚
A ; for Mn(II) complex a = 6.74792 A, b = 8.94387 A, c = 6.29666 A, β = 127.46370 , and cell volume V =
˚
˚
˚
3
˚
301.63610 A .
3.6. Thermal gravimetric analysis
The TGA data agree with the formula suggested from the elemental analyses. The thermal stabilities were
investigated by TGA with a heating rate of 10 ◦ C min−1 in N2 from 50 to 140 ◦ C. The Mn(II), Co(II), Ni(II),
Cu(II), Zn(II), and Cd(II) complexes can suffer from the loss of H2 O in the 50–140 ◦ C range. The complexes
contain 1, 4, 2, 1, 6, and 1 moles of water of crystallization per complex molecule, respectively.
3.7. Genotoxicity study
The data obtained from the Ames mutagenicity test system are presented in Table 5. The px aldehyde-linked
azo chromogene was weakly mutagenic on S . Typhimurium TA98 strains in the absence of s9 mix. On the
432

˙
CABIR et al./Turk J Chem
other hand, the pxoxH2 ligand (2) was strongly mutagenic on S . Typhimurium TA98 strains with and without
s9 mix but it was weakly mutagenic on S . Typhimurium TA100 strains only in the absence of s9 mix. In the
absence and presence of s9 mix, mutagenic activity of the pxoxH2 azo-oxime compound on the TA98 strain was
observed to be dose-dependent (r = 0.954, Figure 9, r = 0.920, Figure 10, respectively).
Table 3. Observed and calculated XRD data of the [Cd(pxoxH)2 (H2 O)2 ].H2 O metal complex.
d-sp. (obs.) d-sp. (cal.) Rel. int.
Sin2θ
Sin2θ
Peak no.
hkl
˚
[A]
˚
[A]
(%)
34.25
64.55
29.78
23.32
100
(obs.)
(cal.)
1
2
7.367228
5.928858
4.672563
3.665163
3.425934
3.32207
7.352391
5.944844
4.672395
3.662953
3.425633
3.317855
3.001352
2.632069
2.434248
2.35826
0.01093
0.01688
0.02718
0.04417
0.05055
0.05377
0.06573
0.08566
0.01098 001
0.01679 101
0.02718 201
0.04422 411
0.05056 501
0.05390 021
0.06587 502
0.08565 302
3
4
5
6
41.3
7
3.004449
2.631851
2.432852
2.35744
14.31
31.99
23.9
8
9
0.010025 0.010014 520
0.010677 0.010669 702
0.015461 0.015458 123
0.016383 0.016381 104
0.016852 0.016858 602
10
11
12
13
15.21
10.78
16.47
12.75
1.959023
1.903099
1.876439
1.959245
1.903204
1.876077
Table 4. Observed and calculated XRD data of the [Mn(pxoxH)2 (H2 O)2 ].H2 O metal complex.
d-sp. (obs.) d-sp. (cal.) Rel. int.
Sin2θ
Sin2θ
Peak no.
hkl
˚
[A]
˚
[A]
(%)
62.33
13.73
100
(obs.)
(cal.)
1
2
3
4
5
6
7
8
5.811424
4.462712
3.435318
3.328647
2.983147
2.929839
2.770278
2.604771
5.811424
4.461999
3.431299
3.327184
2.982109
2.929626
2.770098
2.606827
0.01757 0.01750 200
0.02979 0.02980 210
0.05028 0.05040 011
0.05355 0.05360 120
0.06668 0.06672 220
0.06912 0.06913 111
0.07732 0.07733 121
0.08745 0.08732 021
39.4
15.38
41.98
6.13
12.23
The nickel(II) metal chelate of the azo-oxime ligand [Ni(pxoxH)2 (H2 O)2 ].2H2 O was strongly mutagenic
on S . Typhimurium TA98 strains in the presence and absence of s9 mix. It was weakly mutagenic on S .
Typhimurium TA100 strains in the presence and absence of s9 mix.
While the [Zn(pxoxH)2 ].6H2 O and [Co(pxoxH)2 (H2 O)2 ].4H2 O metal complexes were weakly mutagenic
on S . Typhimurium TA98 strain in the presence and absence of s9 mix, they were not mutagenic on S .
Typhimurium TA100 strain in the presence and absence of s9 mix.
[Cu(pxoxH)2 ].H2 O was not mutagenic on S . Typhimurium TA98 and TA100 strains in the presence
and absence of s9 mix.
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CABIR et al./Turk J Chem
Table 5. The mutagenicity of test substances in Salmonella Typhimurium TA98 and TA100 strains in the absence or
presence of s9 mix.
Cont.
mg/plt.
-
TA 98
TA 100
Test substances
− S9
+ S9
− S9
+ S9
Spontaneous control
12.50 ꢀ 1.93
3510 ꢀ 247
14.67 ꢀ 2.12
103 ꢀ 9.57
135.17 ꢀ 6.04
NPD
2-AF
SA
836.2 ꢀ 45.70
3664 ꢀ 337
743.2 ꢀ 38.2
121.80 ꢀ 10.3
106.00 ꢀ 6.70
119.00 ꢀ 5.20*
106.17 ꢀ 7.17
118.83 ꢀ 5.50*
175.20 ꢀ 23.20*
143.20 ꢀ 20.80
105.67 ꢀ 8.97
82.83 ꢀ 3.08***
73.00 ꢀ 7.87*
300.50 ꢀ 39.70***
166.30 ꢀ 40.50
132.20 ꢀ 19.40
106.00 ꢀ 8.40
97.83 ꢀ 5.59
1.25
1
15.33 ꢀ 1.05*
18.83 ꢀ 2.32*
20.67 ꢀ 2.76*
15.66 ꢀ 0.76*
20.50 ꢀ 2.40*
22.00 ꢀ 3.16
19.00 ꢀ 2.37
121.8 ꢀ 10.30
105.83 ꢀ 6.58**
117.00 ꢀ 5.34*
116.50 ꢀ 7.04*
118.17 ꢀ 5.43*
132.00 ꢀ 13.80
138.80 ꢀ 19.40
103.67 ꢀ 9.39*
94.20 ꢀ 10.40**
70.83 ꢀ 6.18***
271.50 ꢀ 53.80**
201.80 ꢀ 49.30*
131.30 ꢀ 19.20
107.50 ꢀ 8.48*
100.83 ꢀ 5.04***
109.33 ꢀ 7.52*
103.33 ꢀ 8.22*
105.00 ꢀ 9.07*
91.83 ꢀ 5.89***
84.33 ꢀ 8.55***
52.83 ꢀ 5.80***
49.17 ꢀ 7.05***
33.83 ꢀ 4.80***
28.50 ꢀ 2.72***
37.20 ꢀ 15.50***
132.50 ꢀ 14.50
126.00 ꢀ 14.30
110.17 ꢀ 7.82*
98.33 ꢀ 9.75*
Px
0.75
0.50
0.25
1.25
1
20.67 ꢀ 2.76
15.66 ꢀ 0.76
23.50 ꢀ 2.40*
112.33 ꢀ 8.20***
102.50 ꢀ 9.62***
90.00 ꢀ 5.38***
76.83 ꢀ 5.19***
71.17 ꢀ 8.92***
65.70 ꢀ 10.30***
80.20 ꢀ 10.50***
65.70 ꢀ 13.20*
56.50 ꢀ 6.73***
42.00 ꢀ 6.51***
26.50 ꢀ 2.01**
26.50 ꢀ 2.43*
22.67 ꢀ 2.85*
19.50 ꢀ 2.19
122.83 ꢀ 6.17***
99.33 ꢀ 9.27***
95.50 ꢀ 7.46***
77.00 ꢀ 5.26***
61.17 ꢀ 4.65***
72.00 ꢀ 8.56***
77.67 ꢀ 9.91***
57.33 ꢀ 9.33***
52.67 ꢀ 7.58***
38.83 ꢀ 8.90*
26.33 ꢀ 3.40*
27.33 ꢀ 2.60**
19.67 ꢀ 2.04*
20.33 ꢀ 1.73*
19.83 ꢀ 2.50*
20.33 ꢀ 3.32
pxoxH2
0.75
0.50
0.25
0.62
0.49
0.37
0.24
0.12
1.25
1
[Ni(pxoxH)2(H2O)2].2H2O
[Zn(pxoxH)2].6H2O
[Cu(pxoxH)2].H2O
123.30 ꢀ 16.10
102.00 ꢀ 9.74
111.83 ꢀ 7.06
88.33 ꢀ 3.93*
83.67 ꢀ 8.96
0.75
0.50
0.25
0.31
0.24
0.18
0.12
0.06
1.25
1
20.83 ꢀ 2.63
15.67 ꢀ 2.58
58.67 ꢀ 6.49***
47.33 ꢀ 6.56***
36.50 ꢀ 4.94***
29.67 ꢀ 5.51***
37.30 ꢀ 15.50***
138.70 ꢀ 34.10
131.80 ꢀ 17.70
124.70 ꢀ 12.20
89.00 ꢀ 4.02*
83.33 ꢀ 8.92
16.17 ꢀ 2.76
15.17 ꢀ 2.82
10.00 ꢀ 2.13
13.33 ꢀ 3.36
8.67 ꢀ 1.20*
7.67 ꢀ 1.45***
7.67 ꢀ 1.33***
26.33 ꢀ 1.98***
29.33 ꢀ 3.65**
24.50 ꢀ 3.13*
18.33 ꢀ 3.00
7.00 ꢀ 1.24***
29.17 ꢀ 3.63***
31.17 ꢀ 3.46***
20.00 ꢀ 2.44*
19.67 ꢀ 3.01
[Co(pxoxH)2(H2O)2].4H2O
[Mn(pxoxH)2(H2O)2].H2O
[Cd(pxoxH)2(H2O)2].H2O
0.75
0.50
0.25
1.25
1
16.67 ꢀ 1.94
18.67 ꢀ 2.93
84.33 ꢀ 8.49***
114.17 ꢀ 9.63
36.00 ꢀ 3.53***
29.67 ꢀ 3.73***
29.17 ꢀ 4.04***
23.83 ꢀ 1.62***
19.00 ꢀ 4.05
32.67 ꢀ 4.27***
27.17 ꢀ 2.41***
26.00 ꢀ 2.82*
23.83 ꢀ 1.66***
20.00 ꢀ 4.09
135.30 ꢀ 10.80*
108.70 ꢀ 14.70
93.80 ꢀ 10.80
80.00 ꢀ 6.32*
72.67 ꢀ 9.16*
103.33 ꢀ 8.22*
93.30 ꢀ 11.10*
92.30 ꢀ 12.20*
81.20 ꢀ 14.50*
0.75
0.50
0.25
1.25
1
196.50 ꢀ 13.30***
149.50 ꢀ 19.30***
93.70 ꢀ 11.70***
77.33 ꢀ 6.18***
59.17 ꢀ 6.01***
172.00 ꢀ 17.90*** 549.20 ꢀ 83.30*** 451.20 ꢀ 95.00***
145.50 ꢀ 14.30*** 417.70 ꢀ 77.80*** 450.50 ꢀ 92.60***
130.20 ꢀ 19.80*** 328.30 ꢀ 36.20*** 253.00 ꢀ 34.60***
0.75
0.50
0.25
83.00 ꢀ 12.70***
64.83 ꢀ 6.52***
198.70 ꢀ 26.10**
130.80 ꢀ 18.00
197.80 ꢀ 26.60*
127.50 ꢀ 14.00
*: P < 0.05; **: P < 0.01; ***: P < 0.001
NPD: 4-nitro-o-phenylenediamine, 2AF: 2-aminoflourene, SA: sodium azide
[Mn(pxoxH)2 (H2 O)2 ].H2 O was strongly mutagenic on S . Typhimurium TA98 strain in the presence
and absence of s9 mix but was not mutagenic in the presence and absence of s9 mix for the TA100 strain of S .
434

˙
CABIR et al./Turk J Chem
Typhimurium. In addition, the mutagenic activity of [Mn(pxoxH)2 (H2 O)2 ].H2 O on S . Typhimurium TA98
strain was observed to be dose-dependent in the presence and absence of s9 mix (r = 0.983, Figure 11, r =
0.979, Figure 12, respectively).
140
120
100
80
140
120
100
80
y = 19.561x + 9.592
r = 0.954
y = 17.013x + 18.371
r= 0.920
60
60
40
40
20
20
0
0
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Doses (mg/plate)
Doses (mg/plate)
Figure 9. Dose-dependent increase in the mutagenic
activity of (pxoxH2) (2) ligand on TA98 strain in the
absence of s9 mix.
Figure 10. Dose-dependent increase in the mutagenic
activity of (pxoxH2) (2) ligand on TA98 strain in the
presence of s9 mix.
35
40
35
y = 3.248x + 12.689
r = 0.979
30
25
20
15
10
5
y = 4.4243x + 9.5433
r = 0.983
30
25
20
15
10
5
0
0
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Doses (mg/plate)
Doses (mg/plate)
Figure 11. Dose-dependent increase in the mutagenic
activity of [Mn(pxoxH)2 (H2 O)2 ].H2 O complex on TA98
strain in the absence of s9 mix.
Figure 12. Dose-dependent increase in the mutagenic
activity of [Mn(pxoxH)2 (H2 O)2 ].H2 O on TA98 strain in
the presence of s9 mix.
Based on the data obtained from the Ames test, all chemicals tested and their various metabolites
induced the frame-shift mutation except [Cu(pxoxH)2 ].H2 O (TA98). In addition, [Ni(pxoxH)2 (H2 O)2 ].2H2 O
and [Cd(pxoxH)2 (H2 O)2 ].H2 O and also their metabolites induced the base-pair substitutions (TA100). The
pxoxH2 ligand (2) induced the base-pair substitution mutation but not its metabolites. On the other hand,
[Cu(pxoxH)2 ].H2 O and its metabolites did not induce the base-pair substitution mutation.
The [Cd(pxoxH)2 (H2 O)2 ].H2 O complex was strongly mutagenic on S . Typhimurium TA98 and TA100
strains in the presence and absence of s9 mix. The mutagenic activity of [Cd(pxoxH)2 (H2 O)2 ].H2 O ligand on
TA98 (r = 0.981, Figure 13, r = 0.987, Figure 14, respectively) and TA100 (in absence of s9 mix) (r = 0.982,
Figure 15) was observed to be dose-dependent.
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CABIR et al./Turk J Chem
200
180
160
140
120
100
80
250
200
150
100
50
y = 30.739x – 5.886
r = 0.987
y = 34.496x – 22.619
r= 0.981
60
40
20
0
0
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
Doses (mg/plate)
Doses (mg/plate)
Figure 13. Dose-dependent increase in the mutagenic
activity of [Cd(pxoxH)2 (H2 O)2 ].H2 O on TA98 strain in
the absence of s9 mix.
Figure 14. Dose-dependent increase in the mutagenic
activity of [Cd(pxoxH)2 (H2 O)2 ].H2 O ligand on TA98
strain in the presence of s9 mix.
600
500
y = 92.037x – 34.18
r= 0.982
400
300
200
100
0
0
1
2
3
4
5
6
7
Doses (mg/plate)
Figure 15. Dose-dependent increase in the mutagenic activity of [Cd(pxoxH)2 (H2 O)2 ].H2 O on TA100 strain in the
absence of s9 mix.
4. Conclusion
In this work, a new azo-oxime ligand, 2-[(E)-(hydroxyimino)methyl]-4-[(E)-(4-nitrophenyll)diazenyl]phenol
(pxoxH2) (2) (Figure 1) derived from 2-hydroxy5-[(4-nitrophenyl)diazenyl]benzaldehyde (1) and hydroxylam-
minehydrochloride and some of its transition metal complexes was prepared. The analytical data and the spec-
troscopic studies suggested that the complexes had the general formula [M(pxoxH)2 (H2 O)m ].nH2 O, where M
is manganese(II), nickel(II), copper(II), cobalt(II), zinc(II), or cadmium(II). Based on the UV/Vis and IR data
of the 4-nitrophenylazo linked oxime ligand, pxoxH2 was coordinated to the metal ion through the hydroxyimino
nitrogen and phenolic oxygen atoms. Azo-oxime derivative pxoxH2 probably forms a square planar complex
with Cu(II), a tetrahedral complex with Zn(II) ion, and octahedral complexes with Mn(II), Ni(II), Co(II), and
Cd(II) with a metal:ligand ratio of 1:2. Based on the above spectral and analytical data, the proposed struc-
tures of the Mn(II), Ni(II), Cu(II), Co(II), Zn(II), and Cd(II) coordination compounds can be formulated as in
Figure 2. The genotoxicity study indicates that these compounds show weak genotoxicity and the toxicity may
increase with increased dosage.
Acknowledgment
˙
The authors thank the Research Fund of Kahramanmara¸s Su¨t¸cu¨ Imam University for its financial support
(Project no: 2010/3-15M).
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