Synthesis, characterization and biological activities of some metal complexes derived from azo dye ligand 2-[2'-(5-Methyl thiazolyl)azo]-5-dimethylamino benzoic acid

Article abstract of DOI:10.14233/ajchem.2018.21222

In this paper we report the synthesis and identification of Ni(II), Cu(II) and Zn(II) complexes with new thiazole based azo dye 2-[2’-(5-methyl thiazolyl)azo]-5-dimethyl amino benzoic acid (5-MeTAMB) by the diazotization of 2-amino-5-methyl thiazole and c

Full text of DOI:10.14233/ajchem.2018.21222

Asian Journal of Chemistry; Vol. 30, No. 7 (2018), 1537-1545
A
SIAN
J
OURNAL OF HEMISTRY
C
https://doi.org/10.14233/ajchem.2018.21222
Synthesis, Characterization and Biological Activities of Some Metal Complexes Derived from
Azo Dye Ligand 2-[2'-(5-Methyl thiazolyl)azo]-5-dimethylamino Benzoic Acid
*
KHALID J. AL-ADILEE and SUDAD A. JABER
Department of Chemistry, College of Education, University of Al-Qadisiyah, Diwaniya 1753, Iraq
*Corresponding author: E-mail: khalidke_1962@yahoo.com; Khalid.Jawad@qu.edu.iq
Received: 11 January 2018;
Accepted: 18 April 2018;
Published online: 31 May 2018;
AJC-18927
In this paper we report the synthesis and identification of Ni(II), Cu(II) and Zn(II) complexes with new thiazole based azo dye 2-[2’-(5-
methyl thiazolyl)azo]-5-dimethyl amino benzoic acid (5-MeTAMB) by the diazotization of 2-amino-5-methyl thiazole and coupling with
3-dimethyl amino benzoic acid in alkaline alcoholic solution. The structures of the azo dye ligand and its metal complexes were confirmed
by various analytical techniques like by elemental analysis (C.H.N.S), UV-visible, FT-IR spectroscopic, mass spectroscopic, 1H NMR
spectroscopic, SEM, XRD data and thermal studies (TGA & DSC). The magnetic moment value of metal complexes [ML2] M = Ni(II)
and Cu(II) occurs in the range of high spin octahedral environment of azo ligand while Zn(II) complex show diamagnetic properties and
octahedral structure. The analytical and spectral techniques show that the ligand coordinates as tridentate (N,N,O) donor molecule. The
antibacterial and antifungal activity of the thiazolylazo ligand and its metal complexes have shown activity towards both bacterial and
fungal strains. The biological activity was also conducted by cells cytotoxicity and viability of the ligand and Cu(II)-complex was
screened for in vitro, antitumor activity against human breast cancer using MTT assay. The results shows that this type of compounds
plays an important role in the rate of inhibition of the growth of cells of cancerous and natural lines and indicate undoubtedly the
possibility of using them as antitumor drugs against breast cancer.
Keywords: Synthesis, Thiazolylazo dye, Metal complexes, Spectral studies, Biological activity, Anticancerous.
microbial activities such as antibacterial [17], antiviral [18]
and antifungal [19]. In this work describe the preparation and
characterization of new thiazolylazo ligand (5-MeTAMB) and
its complexes with Ni(II), Cu(II) and Zn(II) ions, is described
biological activities (antibacterial and antifungal). The
thiazolylazo ligand and its Cu(II) complex evaluated for in
vitro anticancer activity against human breast cancer MCF7
by MTT assay.
INTRODUCTION
Thiazolylazo dyes are an important class of organic com-
plexion compounds and very important class of chemical
constituents having a wide applications in different fields such
as leather, polymer, paint and coating industries as dyeing agent
[1-3]. The dyeing capability of dye depends on functional groups
present in the dyes, such as azo, hydroxyl, carboxylic acids,
esters and amines [4,5]. The thiazolylazo dyes and its deriva-
tives are also used for colouring consumer goods, such as clothes,
plastics, textiles, food, toys and cosmetics [6,7]. Thiazolylazo
dyes were also used in chemical operations such as spectro-
photometry, solid phase extraction, liquid chromatography,
electrochemistry and cloud point [8-10]. The application of
thiazolylazo dyes in spectrophotometry is based on coloured
compounds resulting from their reaction with metal ions,
especially transition metals [10]. Thiazolylazo derivatives are
active biological agents [11] which possess strong biological
activities such as antihistamines [12], antitumor [13], anti-
inflammatory [14], antibacterial effects [15] and production
of drugs in chemotherapy [16].
EXPERIMENTAL
All the chemicals and solvents were of the highest purity
obtained from BDH, Aldrich, sigma and Merck. Mass spectra
was obtained using a Shimadzu Agilent Technologies 5973C
at 70e and MSD energy using a direct insertion probe (Acq
method 10W energy) at temperature 90-110 °C. 1H NMR spectra
were recorded in DMSO on a Bruker 500 MHZ spectrophoto-
meter using TMS as an interior reference. IR spectra of the
ligand as well as the complexes are recorded as KBr discs
using a Shimadzu 8400 S FT-IR spectrophotometer in wave
number at range (4000-400) cm-1. The electronic spectra of
ligand and its metal complexes were recorded on a T80-PG
double beam UV-visible spectrophotometer in the range of
Thiazolylazo compounds and some of its metal complexes
also show significant effects against cancer and also exhibit

1538 Al-Adilee et al.
Asian J. Chem.
(200-1100) nm in absolute ethanol (10-4 M) solution. Elemental
analysis (C.H.N.S) was performed on a Euro EA 1106 elemental
analyzer. The metal contents of the complexes were measured
using atomic absorption technique by Shimadzu AA-6300.
Magnetic susceptibility measurements of the metal complexes
in powder form were carried out on Balance Magnetic (MSB-
MKI) apparatus. Molar conductivity measurements were made
with DMSO solution (10-3 M) at room temperature using a31A
digital conductivity meter. Melting point apparatus melting
point, SMP, Stuart. pH measurements are carried out using
Philips pw 9421 pH meter (pH 0.001). X-ray diffraction were
measured by using a Shimadzu X-ray diffractometer (XRD
600). TGA analysis were recorded PL-TG using Perkin Elmer
TGA-4000. Scanning electron microscopy (SEM) images of
ligand and its metal complexes were taken using micrograph
ZEISS EM3200.
General method for the preparation of metal complexes:
The metal complexes were prepared using corresponding metal
chlorides and the ligand (5-MeTAMB) amount of 0.580 g
(0.002 mol) from ligand, dissolved in 50 mL of absolute ethanol
was gradually added with stirring a stoichiometric to (0.001
mol) amount of [1:2] M:L for Ni(II), Cu(II) and Zn(II) chloride
salt dissolved in 40 mL hot buffer solution (ammonium acetate)
at pH = 7.0. The mixture was heated to (50-70) °C at 50 min,
then left over night. The separated solid complexes were
filtered off, washed with distilled water and little warm ethanol
to remove any traces of unreacted materials. The complexes
obtained were finally dried under vacuum desiccators over
combined CaCl2. The analytical and physical data of ligand
and its metal complexes are collected in Table-1.
RESULTS AND DISCUSSION
Physical and chemical properties of azo dye (5-MeTAMB):
The thiazolylazo dye ligand is a dark purplish crystals sparingly
soluble in water. It is soluble in methanol, acetone, ethanol
and chloroform but easily soluble in DMSO, DMF and alkaline
aqueous solutions and strongly acidic solutions. It is yellow-
reddish in strongly acidic solution, dark purple in neutral and
violet-bluish in strongly alkaline solution. The equilibrium of
the dissociation can be written as shown (Scheme-II), the
dissociation constants were evaluated by a spectrophotometric
method [22].
Metal:ligand ratio: The composition of metal complexes
were investigated spectrophotometrically by mole ratio method
at fixed concentration and wavelength of maximum absorption
(λmax) of metal ion and increasing amount of ligand solutions
(0.25 mL each add up 3 mL). The colour solutions of metal
complexes increase the intensity, ratio [M:L] and the continued
stability of colour after the point of intersection indicating the
composition of the metal complexes. The molar ratios [M:L]
suggested for the formation of each metal complexes are [1:2]
[23].
Synthesis of azo dye ligand (5-MeTAMB):The new thiazo-
lylazo dye ligand has been synthesized by the diazotization
coupling reaction (Scheme-I) byAl-Adilee [20] and Fan et al.
[21] method with some modification. 2-Amino-5-methyl
thiazole (1.14 g, 0.01 mol) was dissolved in mixture 5 mL of
formic acid and 7 mL of concentrated sulfuric acid, then 16 mL
distilled water were added. To this solution was added drop-
wise a solution of 0.80 g (0.012 mol) of sodium nitrite (NaNO2)
in 35 mL distilled water at (0-5) °C and the mixture was stirred
for 30 min at (0-5) °C. The resulting diazonium solution was
added drop-wise with cooling and stirring continuously at (0-
5) °C in to beaker (500 mL) containing 1.65 g (0.01 mol) of
3-dimethyl amino benzoic acid was dissolved in 10 mL of
pyridine and 30 mL of methanol and cooled to (0-5) °C. The
mixture was stirred for 2 h in an ice-bath and allowed to stand
overnight. The precipitate formed was filtered off and first
purified by the base-acid recrystallized method and further
purified by recrystallization from DMF-water (1:1). A dark
purplish crystals, which decomposes at 198 °C, was obtained
in a yield of about 83 %. The purity was confirmed by the
element analysis and TLC techniques. Its structure was verified
by 1H NMR, mass spectrum, IR and UV-visible spectrometry.
Molar conductivity measurements: The molar conduc-
tance of prepared metal complexes are shown in Table-2,
H3C
S
N
NaNO2
H3C
S
N
NH2
-
N
N+HSO4
H2O
(0-5) oC
2-Amino-5-methyl thiazole disolved in
Diazonium Salt
mi xture 5ml f ormi c acid +7ml conc.H2SO4
O
OH
C
H3C
H3C
N
S
N
H3C
S
N
H3C
-
N+HSO4
N
N
CH3
CH3
N
N
In mixture 10ml pyridin
+ 30 ml methanol
HO
C
Diazonium Salt
O
HL=(5-MeTAMB)
Scheme-I: Synthesis of ligand (5-MeTAMB)

Vol. 30, No. 7 (2018) Synthesis, Characterization and Biological Activities of Some Metal Complexes Derived from Azo Dye Ligand 1539
TABLE-1
PHYSICAL PROPERTIES AND ELEMENTAL ANALYSIS FOR LIGAND (5-MeTAMB) AND ITS METAL COMPLEXES
Elemental analysis (%): Found (calcd.)
m.p.
(°C)
Yield
(%)
m.f.
(m.w.)
Compd.
Colour
C
H
N
S
M
–
C13H14N4O2S
(290.34)
C26H28N8O5S2Ni
(655.37)
C26H28N8O5S2Cu
(660.22)
C26H28N8O5S2Zn
(662.09)
54.31
(53.77)
48.12
(47.64)
47.81
(47.29)
47.35
(47.16)
4.95
(4.86)
4.05
(4.03)
4.02
(4.27)
4.32
(4.26)
19.16
(19.29)
17.38
(17.09)
17.35
(16.97)
17.28
(16.92)
11.22
(11.04)
10.05
(9.78)
10.17
(9.71)
5-MeTAMB (L)
[Ni(L)2]·H2O
[Cu(L)2]·H2O
[Zn(L)2]·H2O
Dark purplish
Greenish blue
Blue
198
240
231
243
83
79
77
69
9.17
(8.95)
9.81
(9.62)
10.18
(9.87)
9.49
(9.68)
Violet
H3C
S
N
H3C
H3C
S
N
N
S
N
N
N
N
CH3
CH3
pka1=1.23
H+
pka2=3.65
H+
CH3
N
CH3
CH3
N+
N
N
N
CH3
H
C
C
-O
HO
C
O
O
HO
O
pH = 7.5-9.5; [L–] anion form,
violet
+
pH = 4.0-7.0; [LH] neutral form,
purple
pH
≤
2.5; [LH2 ] protonated form,
yellow-reddish
λ
max = 440 nm
λ
max = 567 nm
λ
max = 468 nm
) = 2.37 × 103 L mol–1 cm–1
(
ε
) = 9.7 × 103 L mol–1 cm–1
) = 1.28 × 103 L mol–1 cm–1
(
ε
(
ε
Scheme-II: Equilibrium of the dissociation of thiazolylazo dye ligand (5-MeTAMB)
TABLE-2
OPTIMAL CONCENTRATION, MAXIMUM WAVELENGTH (λmax), MOLAR ABSORPTIVITY (ε), STABILITY
CONSTANTS VALUES (β AND log β) AND MOLAR CONDUCTIVITY OF METAL COMPLEXES
ε × 103
Metal
ion
Optimal conc.
Molar conductance
(S cm–1 mol–1)
5-MeTAMB
max = 440 nm
λ
max (nm)
β (L2 mol–2)
1.527 × 1012
7.049 × 1010
2.185 × 1011
log β
× 10–4
1.50
1.75
1.25
M
(L mol–1 cm–1)
Ni(II)
Cu(II)
Zn(II)
625
527
608
19.68
34.28
11.01
12.181
10.894
11.339
10.27
9.03
13.28
λ
ε = 9.7 × 103 L mol–1 cm–1
Conc. = 1.50 × 10–4
M
carried out in DMF (10-3) at room temperature. The values of
conductivity indicated that the metal complexes of Ni(II),
Cu(II) and Zn(II) ions are non-electrolytes in nature [24].
Calculation stability constants (β): Stability constants
(β) values of metal complexes are obtained spectrophoto-
metrically by measuring the absorbance of solution of the
ligand and metal ion solution at fixed wavelength (λmax) and
optimum concentration at pH = 7.0. The degree of formation
of the metal complexes are obtained by the relationship,
tants of metal complexes according to the following sequence:
Ni(II) > Cu(II) > Zn(II). The sequence of metal ions of the
first row transition metal agree with Irving-Williams series of
stability constant [26].
1H NMR spectra: The 1H NMR spectra of thiazolylazo
dye ligand (5-MeTAMB) and Zn(II) complex [27] was measured
in DMSO-d6 as solvent with TMS as an internal reference (500
MHz). This compounds have been studied and listed in Table-3.
Infrared spectral studies: IR spectral data of the prepared
thiazolylazo dye ligand (5-MeTAMB) and its metal complexes
with Ni(II), Cu(II) and Zn(II) ions are presented in Table-4.
The shifts in the position or change in the shape of the metal
complexes bands compared with those absorption bands of
free ligand due to the formation of the metal complexes bands
3
β = (1-α)/4α c2 and α = Am-As/Am, where Am and As are the
absorbance of fully and partially formed metal complex
respectively at optimum concentration [25]. The stability
constants of metal complexes values for the preparation of
metal complexes are listed in the Table-2. The stability cons-
TABLE-3
1H NMR SPECTRA OF THIAZOLYLAZO DYE LIGAND (5-MTAMB) AND ITS Zn(II) COMPLEX
Ligand (5-MeTAMB) δ, ppm
(H atoms, peak, assignment)
Zn(II) complex δ, ppm
(H atoms, peak, assignment)
J-J coupling
J-J coupling
2.444 (DMSO-d6)
2.896 (6H, S, 16, 17)
3.437 (3H, S, 6)
7.089-7.135 (1H, d, 13)
7.252-7.277 (1H, d, 14)
7.367 (1H, S, 4)
5.984
11.218
6.148
2.168
2.222
2.292
2.790
2.062
2.984 (DMSO-d6)
3.052 (6H, S, 6, 25)
3.523 (12H, S, 16, 17, 36, 37)
5.384 (2H, S, H2O)
6.917 (2H, S, 4, 24)
7.106-7.136 (2H, d, 13, 32)
7.171 (2H, S, 11, 30)
8.084-8.197 (2H, d, 14, 33)
31.113
15.567
31.563
6.557
5.952
5.000
5.391
5.567
7.653 (1H, S, 11)
10.675 (1H, S, 19)

1540 Al-Adilee et al.
Asian J. Chem.
of free ligand. Depend on IR spectral data lead to suggest that
ligand (5-MeTAMB) behaves as a tridentate chelating agent
coordinating with metal ions by a carboxylic oxygen, azo
nitrogen which is the farthest of thiazole ring and nitrogen
atom in thiazole ring to forming two five membered chelating
ring [28].
TABLE-4
KEY IR (cm–1) BANDS OF THIAZOLYLAZO DYE
LIGAND (5-MeTAMB) AND ITS METAL COMPLEXES
Ligand
(LH)
[Zn(L)2]·H2O [Cu(L)2]·H2O [Ni(L)2]·H2O
Group
3445 m,br
(H2O)
3447 m
(H2O)
3418 m,br
(H2O)
3458 m
-COOH
Mass spectra: The mass spectrum of thiazolylazo dye
ligand (5-MeTAMB) showed a molecular ion peak M+ at m/z+
= 290.30 attributed to the original molecular weight of ligand
(290.34) (Fig. 1). The mass spectrum of Cu(II) complex showed
a molecular ion peak M+ at m/z+ = 660.21, equivalent to its
molecular weight supporting the suggested structure for Cu(II)
complex (Fig. 2). The result of the expected mass fragmen-
tation have shown that they correspond to mass spectra of the
ligand (5-MeTAMB) and its Cu(II) complex [29].
Electronic spectra and magnetic susceptibility measure-
ments: The electronic absorption spectra of ligand (5-MeTAMB)
and its metal complexes with Ni(II), Cu(II) and Zn(II) ions
were recorded in freshly prepared absolute ethanol solution
3192 m,br
3348 s
3368 w
3073 m
ν(C-H)
Ar-ring
ν(-CH3)
νN(CH3)2
ν(C=O)
ν(C=N)
ν(N=N)
Ar-ring
2924 w
2859 s
1649 m
1599 m,sh
1524 s
1398 m
823 w
1451 m
2924 w
2850 w
1651 m
1595 s
1524 s
1391 m
846 w
1452 w
3102 w
2926 s
1651 m
1595 s
1526 m
1394 s
864 w
2924 m
2884 w
1713 m
1600 w
1560 s
1388 w
765 m
–
ν(COO–)
asym.
ν(COO–)
sym.
M-O
M-N
1395 s
1398 s
1391 m
1394 s
–
615 w
519 w
596 w
515 w
605 w
521 w
–
–
163.9
3.8×107
3.6×107
3.2×107
3.0×107
2.8×107
2.6×107
2.4×107
2.2×107
2.0×107
1.8×107
1.6×107
1.4×107
1.2×107
1.0×107
8.0×106
6.0×106
4.0×106
2.0×106
188.2
61.9
214.1
228.0
93.0
202.2
280.2
289.3
260.0
255.1
172.0
171.0
112.0
119.9
83.9
79.7
242.1
45.9
67.1
143.0
217.0
108.0
98.9
245.1
35.0
0
20
40
60
80
100
120
140
160
m/z (Da)
180
200
220
240
260
280
300
Fig. 1. Mass spectrum of thiazolylazo dye ligand (5-MTAMB)
188.2
4.6×106
4.4×106
4.2×106
4.0×106
3.8×106
3.6×106
3.4×106
3.2×106
3.0×106
2.8×106
2.6×106
2.4×106
2.2×106
2.0×106
1.8×106
1.6×106
1.4×106
1.2×106
1.0×106
8.0×105
6.0×105
4.0×105
2.0×105
0
642.2
55.0
216.0
96.9
173.0
233.2
201.0
288.0
351.8
342.1
89.0
113.1
125.1
242.1
255.2
311.8
362.2
390.4
45.0
68.9
660.2
421.3
513.0
454.2
482.0
527.3
557.4
50
100
150
200
250
300
350
m/z (Da)
400
450
500
550
600
650
Fig. 2. Mass spectrum of Cu(II) complex; [Cu(L)2]·H2O

Vol. 30, No. 7 (2018) Synthesis, Characterization and Biological Activities of Some Metal Complexes Derived from Azo Dye Ligand 1541
(10-3 M) at room temperature. The spectral data and electronic
transitions (nm, cm-1) are presented in Table-5. The electronic
spectrum of free ligand show three absorption bands at 250
nm (40000 cm-1), 295 nm (33898 cm-1) and 440 nm (22727
cm-1).
The first band can be due to a π→π* transition in thiazole
ring [25], while the second band assigned to π→π*of the two
interact (C=C) group of atomic of aromatic and thiazole ring
and third band due to n→π* of the azo group (-N=N-). This
band was shown at a red shift on coordination with a metal
ions [23].
moment value of 2.94 B.M. because of the presence of two
unpaired electrons which indicates an a regular octahedral
geometry (t2g6 eg2) high spin and sp3d2 hybridization [34]. The
Cu(II) complex showed the magnetic moment value 1.78 B.M.
due to the presence of one unpaired electron which may suggest
a distorted octahedral geometry (t2g6eg3) and sp3d2 hybridi-
zation [38]. The magnetic moment for Zn(II) complex shows
a diamagnetic behaviour as it is diamagnetic complex with d10
configuration (t2g6 eg4) and sp3d2 hybridization [35].
Thermogravimetric analysis: Thermogravimetry (TG)
is a technique in which the change in mass of the sample is
determined as a function of time or temperature. Among all
the methods, TG is the most widely used one. From TG curve,
information related to the thermal stabilities, composition of
the initial sample. The middle case compounds that are formed
and in the final residue could be obtained [36]. The differential
scanning calorimetric (DSC) and thermogravimetric analyses
(TGA) curves for the ligand HL and its metal complexes are
presented in Fig. 4, Table-6 illustrates the thermal analyses curves
of the of ligand (5-MeTAMB) and its M(II) complexes.
The electronic spectrum of the Ni(II) complex displayed
bands at 856 nm (11682 cm-1), 625 nm (16000 cm-1) and 392 nm
3
(25510 cm-1). These three bands are attributed to 3A2g→ T2g
3
3
(ν1), 3A2g→ T1g(F) (ν2) and 3A2g→ T1g(p) (ν3) transitions respec-
tively in octahedral structure [30]. The Cu(II) complex exhi-
bited a single broad band around at 527 nm (18975 cm-1). The
broadness band indicates the three transitions 2B1g→ A1g (ν1),
2
2B1g→ B2g (ν2) and 2B1g→ Eg (ν3), which are of similar energy
2
2
and give rise to only one broad absorption band (2B1g→ Eg)
2
and suggest distortion octahedral geometry of the Cu(II)
complex [31,32].
1.65
100.05
95
d
1.0
The electronic absorption spectrum of the Zn(II) complex
did not show any d-d transition because of saturation with
electrons (d10). The Zn(II) complex exhibited one absorption
band at 608 nm (16447 cm-1) assignable to charge transfer
[dπ(Zn2+)→π*(HL)] transition where π* (HL = 5-MeTAMB)
was believed to be primarily dominated by the LUMO of the
azo imine chromosphere [33]. UV-Visible spectra of the ligand
and its metal complexes are shown in Fig. 3.
90
85
80
75
a
0.5
0
b
d
c
a
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
-3.5
-4.0
b
70
65
60
55
(a) HL (5-MeTAMB)
(b) Ni(II) complex
(c) Cu(II) complex
(d) Zn(II) complex
c
50
40.32100
200
300
400
500
600
700
807.3
Temperature (°C)
1.700
Fig. 4. Thermal analysis (TGA and DSC) of ligand (5-MeTAMB) and its
M(II) complexes
(a) HL = (5-MeTAMB)
(b) Ni(II) complex
(c) Cu(II) complex
(d) Zn(II) complex
1.358
1.016
0.674
0.332
-0.010
d
Powder X-ray diffraction: Crystallinity and crystal phases
of the as-synthesized ligand (5-MeTAMB) and its metal comp-
lexes nanoparticles were analyzed. The (XRD) patterns of
ligand and complexes are shown in Fig. 5. The XRD of ligand
and its complexes were recorded in the range of 5-80° (2θ)
value, arising from diffraction of X-ray by planes of complex.
The interplanar spacing (d) has been calculated from the
position of intense peak using Bragg’s equation: ηλ = 2d sin
θ, where λ = wavelength of X-ray used (CuKα = 1.54A), η is
an integer (1, 2, 3, 4 …), θ is the diffraction angle [37]. The 2θ
values for the prominent peaks and the calculated spacing
together with relative intensities with respect to most intense
c
a
b
190
400
Wavelength (nm)
600
800
Fig. 3. UV-visible spectra of ligand (5-MeTAMB) and its metal complexes
with Ni(II), Cu(II) and Zn(II) ions
Magnetic susceptibility studies:The magnetic moments
obtained at room temperature for Ni(II) and Cu(II) complexes
are listed in Table-5. The Ni(II) complex exhibited the magnetic
TABLE-5
ELECTRONIC SPECTRA (nm AND cm–1); MAGNETIC MOMENTS; PROPOSED
GEOMETRY AND HYBRIDIZATION OF PREPARED METAL COMPLEXES
Compounds
HL
Absorption bands (cm–1)
Transitions
µeff (B.M.)
Geometry
Hybridization
–
λ
max (nm)
440
295
250
22727
33898
116000
11682
16000
25510
18975
16447
π→π*
n→π*
n→π*
–
–
3A2g→3T2g(F) (ν1)
3A2g→3T1g(F) (ν2)
3A2g→3T1g(P) (ν3)
2B1g→2Eg
856
625
392
sp3d2
(high spin)
Ni(II) complex
2.94
Octahedral (regular)
Cu(II) complex
Zn(II) complex
527
1.78
Octahedral (distorted)
Octahedral (regular)
sp3d2
sp3d2
dπ(Zn)2+→π*(HL)
608
Diamag.

1542 Al-Adilee et al.
Asian J. Chem.
TABLE-6
THERMAL ANALYTICAL RESULTS (TGA, DSC) OF LIGAND (5-MeTAMB) AND ITS METAL(II) COMPLEXES
Mass loss (%)
Estimated (calcd.)
TGA range
(°C)
Compound
5-MeTAMB
[Ni(L)2]·H2O
Probable assignments
Loss of dimethyl amine group
DSC
120-202
202-528
98-271
271-464
80-100
3.06 (2.88)
20.60 (19.41)
9.50 (10.33)
20.62 (19.88)
2.73 (3.49)
(+) 450
Evolution CH4, CO2 gases
Loss H2Omolecule and liberation N2O gas.
Evolution CH4, CO2 gases and formation of NiO
Loss H2Omolecule
(-) 270
[Cu(L)2]·H2O
[Zn(L)2]·H2O
130-171
171-390
150-263
263-412
20.60 (21.21)
22.30 (23.00)
2.71 (2.55)
Loss of N,N-dimethyl aniline group
Evolution CH4, CO2 gases and formation of CuO
Loss H2Omolecule
(-) 170
(+) 213
6.21 (6.27)
Liberation N2O gas
(+) 296
are agglomerated and non-uniform particles are observed in
some cases. Moreover, SEM micrographs (Fig. 6) of the metal
complexes revealed that the surface morphology of metal
complexes is changed by changing the metal ions [39]. The
calculations of particles size were performed utilizing Menisci
software.
The analysis of SEM for Ni(II) complex appeared in the
form of a small particle size is heterogeneous surface and the
average particle size of 103 nm, either the analysis of SEM
for Cu(II) appeared in the form of heterogeneous surface
and the average particle size 139 nm. The SEM image of Zn(II)
complex seemed heterogeneous surfaced with average particle
size 250 nm.
(a) HL (5-MeTAMB)
(b) Ni(II) complex
(c) Cu(II) complex
(d) Zn(II) complex
(d)
(b)
(c)
(a)
5
15
25
35
45
55
65
75
2θ (°)
Fig. 5. Powder X-ray diffraction data of ligand (5-MeTAMB) and its M(II)
complexes
Antibacterial and antifungal activity: Antimicrobial
activity was carried out by the cup-plate method [40,41]. The
ligand (5-MeTAMB) and its Ni(II), Cu(II) and Zn(II)
complexes have been tested for their antibacterial and anti-
fungal activity at 1 mg/mL concentration, DMSO is used as
solvent. The results of antimicrobial activity have been statis-
tical presented in Fig. 7, which showed that the ligand and
Zn(II) complex of showed less activity against S. aureus and
E. coli when compared with that of standard drug streptomycin.
The Cu(II) complex of showed good activity while Ni(II)
complex of exhibited moderate activity against S. aureus, when
compared with that of standard drug streptomycin.
The results of the antifungal activity of Ni(II) complex
showed good activity against A. niger when compared with
standard drug fluconazole at the same concentration as that of
the test compound and DMSO is used as solvent. The ligand
and Cu(II) and Zn(II) complexes of showed less activity against
A. niger when compared with standard drug fluconazole.
peak have been listed in Table-7. The crystallite size is calcu-
lated using Debye-Scherrer equation [38]:
0.94λ
Dp =
β1/2 cosθ
where Dp = average crystallite size, β = line broadening at
half the maximum intensity in radians, θ = Bragg angle, λ =
X-ray wavelength.
SEM analysis: Scanning electron microscopy (SEM) of
the ligand (5-MeTAMB) and its metal complexes studies the
surface morphology and state of the particles and accumu-
lation, in addition to the distribution of these particles. The
SEM image of ligand and metal complexes have been repre-
sented in Fig. 6.
SEM image shows the ligand (5-MeTAMB) have form of
spherical shape with average size 73 nm with a ratio of less than
aggregation. The SEM complexes showed that the particles
TABLE-7
POWDER X-RAY DIFFRACTION DATA OF LIGAND (5-MeTAMB) AND ITS METAL(II) COMPLEXES
Compound
No.
dobserved (Å)
I/Io (%)
FWHM
Crystallite size (nm)
Lattice strain
2θobserved (°)
31.7832
45.4763
66.2563
31.5914
19.2152
45.3805
16.1826
32.2991
39.6701
23.0609
6.7101
1
2
3
1
2
3
1
2
3
1
2
3
2.821000
1.994000
1.409000
2.82982
4.61535
1.99689
5.47279
2.76941
2.27017
3.85364
13.16230
68090.2
100
15
8
100
79
53
100
99
77
100
91
36
0.14290
0.20500
0.15530
0.86000
0.18000
0.66000
0.35990
0.52290
0.52000
0.12760
0.21530
0.12750
60.77
63.33
63.82
10.03
46.76
13.63
23.30
16.53
16.97
66.4
0.0022
0.0015
0.0010
0.0133
0.0046
0.0069
0.0110
0.0079
0.0063
0.0027
0.0160
0.0019
5-MeTAMB
Ni(II) complex
Cu(II) complex
Zn(II) complex
38.62
67.97
33.3962

Vol. 30, No. 7 (2018) Synthesis, Characterization and Biological Activities of Some Metal Complexes Derived from Azo Dye Ligand 1543
Fig. 6. SEM images of ligand (5-MeTAMB) and its prepared metal complexes
where the number of the remaining living cells after the reaction
with Cu(II) complex. The ligand for is observed that the highest
ratio of the inhibition for the cancerous cell line of the breast
MCF-7 is 47.47 % whereas the ratio of the normal cell line
WRL is 77.67 % for the living cells when concentration of
200 µg mL–1 and this indicates that Cu(II) complex has a higher
efficiency than the ligand inhibiting the growth of cancerous
cells Cu(II) complex is observed that the highest ratio of the
inhibition for the cancerous cell line of the breast MCF-7 is
47.5 % whereas the ratio of the normal cell line WRL is 92.4 %
for the living cells when concentration issued 100 µg mL–1.
The screening results are given in Table-8. The reason behind
this inhibition of the growth of cancer cell is that the ligand
and Cu(II) complex include thiazole ring which has a high
efficiency in inhibiting or stopping the growth of cancer cells.
Moreover, increasing the efficiency in inhibiting the growth
of cancer cells by using Cu(II) complex is more than that in
the ligand because it includes two thiazole rings [44].
14
12
10
8
HL (5-MeTAMB)
Ni(II) complex
Cu(II) complex
Zn(II) complex
6
4
2
0
A. niger
S. aureus
E. coli
Fig. 7. Statistical representation for biological activity of ligand (5-
MeTAMB) and its metal complexes
in vitro Cytotoxicity assays: Chemotherapy is the major
approach for both localized and metastasized cancer [42,43].
Therefore, the ligand (5-MeTAMB) and its Cu(II) complex were
screened for their in vitro cytotoxicity and growth inhibitory
activities against human tumor cell line breast cancer cell line
MCF-7.
The relation between the biological activity of the
cancerous line cell of the breast MCF-7 and normal line cells
of the breast WRL and the concentration of the ligand and its
complex with Cu(II) ion. It is observed that the inhibition of
the ligand (5-MeTAMB) differs with difference of cell line
The cytotoxicity of the tested compounds was expressed
by IC50 median growth inhibitory concentration which required
producing 50 % cytotoxic effect against cancer cells after 24 h
exposure to tested compounds. The screening results shown
in Figs. 8 and 9. It is evident that for MCF-7 cells, the tested
(5-MeTAMB) and its Cu(II) complex showed anticancer

1544 Al-Adilee et al.
Asian J. Chem.
TABLE-8
EFFECT OF LIGAND (5-MeTAMB) AND Cu(II) COMPLEX ON BREAST CANCEROUS CELLS MCF7 VAIBILITY AND
COMPARISON WITH NATURAL CELLS LINE (WRL-68) FOR SAME CONCENTRATION USING 24 h MTT TEST AT 37 °C
5-MeTAMB
Cu(II) complex
Cancerous line cells
of breast MCF7
Conc.
Cancerous line cells
of breast MCF7
Normal line cells
of breast WRI-68
Normal line cells
of breast WRI-68
(µg mL–1)
Mean
–
100.00
97.62
90.66
84.27
SD
–
Mean
47.33
30.36
53.58
100.00
61.61
SD
Mean
98.6
99.9
100.0
84.6
47.5
SD
Mean
73.9
83.2
78.8
100.0
92.4
SD
6.25
12.5
25
44.3
15.7
31.4
51.5
82.8
55.1
65.9
1.73
1.14
6.09
7.59
9.80
1.70
7.74
12.10
12.48
13.89
31.80
38.98
8.59
5.1
12.2
16.9
15.0
3.4
4.7
50
100
200
400
47.47
77.67
33.0
54.1
4.74 × 10–15
1.26 × 10–13
6.5 × 10–15
5.2 × 10–14
21.42
activity with IC50 values that ranged of concentration from
6.25 to 400 µg mL–1. in vitro Cytotoxicity of the ligand (5-
MeTAMB), on human cell lines MCF-7, (HL) showed cytoto-
xicity against cancer cell line with IC50 = 183.5 µg/mL; WRI-
68 IC50 = 210.2 µg/mL, while Cu(II) complex showed selective
cytotoxicity against cancer cell line with IC50 = 109.9 µg/mL;
WRI-68 IC50 = 205.0 µg/mL. The results showed that the type
of compound plays an important role in the rate of inhibition
of the growth of cells of cancerous and natural lines.
H3C
S
N
CH3
CH3
N
N
O
N
O
.H2O
C
M
O
C
O
H3C
H3C
N
N
N
N
CH3
S
160
HL
M = Ni(II), Cu(II) and Zn(II)
WRI-68
log IC50 of HL = 2.264
(183.5 µg/mL)
120
80
40
0
Fig. 10. Proposed structural formula of M(II) complexes
with line of the ordinary cells, through tests conducted to
identify the possibility of using the ligand and Cu(II) complex
as drugs to treat some cancerous diseases that affect humans.
log IC50 of WRI-68 = 2.323
(210.2 µg/mL)
1
2
3
-40
log concentration (µg/mL)
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