Synthesis and characterization of newly synthesized Schiff base ligand and its metal complexes as potent anticancer

Article abstract of DOI:10.1016/j.molstruc.2018.12.055

2-((2-mercaptophenyl)imino)-1,2-diphenylethan-1-ol(H₂L) Schiff base ligand from benzoin and 2-aminothiophenol was prepared and characterized. The Co(II),Cd(II),La(III), and Gd (III) complexes was prepared in bulk size and La(III) complex also p

Full text of DOI:10.1016/j.molstruc.2018.12.055

Accepted Manuscript
Synthesis and Characterization of newly synthesized Schiff base ligand and its
metal complexes as potent anticancer
Rania H. Taha, Zienab A. El-Shafiey, Aida A. Salman, Esmail M. El-Fakharany,
Mai M. Mansour
PII:
S0022-2860(18)31481-9
10.1016/j.molstruc.2018.12.055
MOLSTR 25992
DOI:
Reference:
To appear in:
Journal of Molecular Structure
Received Date:
Accepted Date:
19 September 2018
12 December 2018
Please cite this article as: Rania H. Taha, Zienab A. El-Shafiey, Aida A. Salman, Esmail M. El-
Fakharany, Mai M. Mansour, Synthesis and Characterization of newly synthesized Schiff base
ligand and its metal complexes as potent anticancer, Journal of Molecular Structure (2018), doi:
10.1016/j.molstruc.2018.12.055
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ACCEPTED MANUSCRIPT
Synthesis and Characterization of newly synthesized Schiff base ligand and its
metal complexes as potent anticancer
Rania H. Tahaa, b*, Zienab A. El-Shafieya, Aida A. Salmana, Esmail M. El-Fakharanyc
and Mai M. Mansoura
aDepartment of Chemistry, Faculty of Science (Girls), Al-Azhar University, P.O. Box: 11754,
Yousef Abbas Str., Nasr City, Cairo, Egypt
bChemistry Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi
Arabia
c
Protein Research Department, Genetic Engineering and Biotechnology Research Institute
(GEBRI), City of Scientific Research & Technological Applications (SRTA-City), New Borg
El-Arab City, P.O. Box: 21934 Alexandria, Egypt
* rhaly@ju.edu.sa, mhmd_mosad@yahoo.com
Abstract
2-((2-mercaptophenyl)imino)-1,2-diphenylethan-1-ol(H2L) Schiff base ligand from
benzoin and 2-aminothiophenol was prepared and characterized. The Co(II),Cd(II),La(III) ,
and Gd (III) complexes was prepared in bulk size and La(III) complex also prepared in nano
size. The Schiff base and its complexes was characterized by elemental analysis, 1HNMR, IR,
Mass spectroscopy, UV-VIS spectra, thermal analysis, conductivity measurements, and
magnetic moments. The selected analyses showed that the complexes are octahedral and non-
electrolytic in nature and the azomethine nitrogen wasn't participated in complexation. The
ability of the free ligand to remove different heavy metals was studied. The cytotoxicity
effect of Cd(II) complex sing MTT method exhibited a significant nontoxic behavior and
higher cell viability on Vero, Caco-2 and MCF-7 cells than the free ligand itself. The
cytotoxicity results revealed that the Cd(II) complex could become safe to be used as
anticancer agent for Vero, Caco-2 and MCF-7 cells. By examining its pharmacological
activity, we were able to identify new potent and selective anticancer.
Key words: Schiff base, aminothiophenol, cytotoxicity, Vero cells, Caco-2 cells and MCF-7
cells
Introduction
Schiff base ligand is a compound which prepared by the condensation reaction between
aldehyde or ketone with a primary amine [1,2]. The product group is called azomethine group
–C=N–. The active groups in the ligand play an important role in its applications. The Schiff
base complexes can be prepared by the reaction between the ligand and the metal salts. The
Schiff base and its complexes have variables application according to the active groups. They

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have applications in industry, pharmacology, biological activities, antimicrobial,
antibacterial, anticancer activities, and metallic enzymes preparations [3-9].
Metal complexes of sulpher-containing Schiff bases have received a big attention due to
the remarkable antitumor, antibacterial, and antiviral properties.
Schiff base ligand formed from the condensation of benzoin with 2-amino thiophenol and its
Co(II), Cd(II), La(III), and Gd(III) complexes were reported in this paper .
Experimental
Benzoin, 2-amino thiophenol, CoCl2.6H2O, CdCl2.H2O, La(NO3)3.6H2O,
Gd(NO3)3.6H2O , and ethyl alcohol , etc. were purchased from (Aldrich) and used without
purification. The elemental analysis (C,H,N,S ) were performed using EL elemental
analyser at the microanalytical center, Cairo university , Giza , Egypt . The IR spectra were
recorded as KBr discs using a Perkin-Elmer 437 IR spectrometer (400-4000 cm-1). Mass
spectra were recorded at 70 eV and 3000C on a Hewlett-Packard Mass spectrometer model
MS 5988. The proton NMR spectra (DMSO – d6) were recorded on a Pruker FT-400MHZ
spectrometer without using internal standard. Electronic (UV – VIS) spectra were recorded
on a Schimadzu UV-spectrophotometer in the range (200-800 nm) using (DMSO) solvent.
Thermal analyses were carried out using Thermogravimetric analyzer TGA-50 SHIMA VZU
-1
and DTA, TA50 Shimadzu in dynamic nitrogen atmosphere with a heating rate 100C min .
The magnetic susceptibility measurements of the complexes were carried out using Gouy
balance. The molar conductance was measured on JEN WAY 4510 conductivity meter using
DMF as the solvent at room temperature.
Synthesis of Schiff base ligand
The ligand fig (1) was synthesized by using the previously published ordinary
methods[10].To the ethanolic solution of benzoin (7.07 g, 0.025 mol) an ethanolic solution of
2-amino thiophenol (3.56 ml, 0.025 mol) was added (1:1 molar ratio), the reaction mixture
was refluxed for 4h in a water bath then cooling the reaction mixture. Then the product was
collected by filtration , washed several times with ethanol and diethyl ether then dried in a
desiccator over anhydrous calcium chloride to give 80.99% yield page powder of Schiff
base ligand .

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O
OH
H2N
+
HS
2-amino thiophenol
benzoin
OH
C
N
C
H
SH
2-((2-mercaptophenyl)imino)-1,2-diphenylethan-1-ol
Fig (1): schematic representation of synthesis of bidentate ligand H2L .
Synthesis of metal complexes in bulk size[11]
Metal complexes were prepared by adding (0.0025 mol) of ethanolic solution of
CoCl2.6H2O ,CdCl2..H2O, La(NO3)3.6H2O , or Gd(NO3)3.6H2O to a hot solution of Schiff
base ligand (0.0025 mol)then the mixture was stirred and reflux for 2 h. The product was
collected by filtration, washed with ethanol and diethyl ether then dried in a desiccator.
Synthesis of La complex in Nano sizeby green chemistry method[12]
10 ml of a 0.1 M solution ofLa(NO3)3.6H2O in EtOH were positioned in a high-density
ultrasonicprobe, operating at 24 kHz with a maximum power output of 400 W. Into this
solution 10 ml of a 0.1 M solution of the ligands were added drop wise. The obtained
precipitate was allowed to evaporate at room temperature to obtain La complex nanoparticle
in dark gray powder form.

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Cytotoxicity Assay
Different concentrations of the free ligand and its metal complexes both in bulk and
nano size were tested for their cytotoxicity against Vero, Caco-2 and MCF-7 cell lines using
(MTT) Thiazolyl Blue Tetrazolium Bromide method according to [13,14]. In brief, Vero,
Caco-2 and MCF-7cells (10×103) were cultured in a 96 well plate for overnight at 37ºC, 5%
CO2 and 88% humidity. The total volume of used DEMEM supplemented medium and the
synthesized compounds supernatant was 200 μLwith final concentrations of 10, 20, 30, 40,
60, 80 and 100 mg/L. The plate was incubated at 37ºC, 5% CO2 for 3 d. After incubation,
debris, and dead cells were removed by washing three times with fresh medium. Twenty μL
of MTT solution (5 mg/mL of MTT in PBS buffer) was added to each well and shook for 5
min at 150 rpm to thoroughly mix the MTT into the media. The cells were incubated at 37ºC
and 5% CO2 for 3-5 h to metabolize MTT by viable cells. 200 μLdimethylsulfoxide (DMSO)
was added to each well and shook again for 5 min at 150 rpm, and then the viability of the
cells was calculated by measuring the optical density at 630 nm subtracted from optical
density at 570 nm [15]. The percentage of viability cells was calculated by comparison with
control cells (without adding the synthesized compounds to the cells) using the equation of:
(A) test/ (A) control × 100.
Results and discussion
The prepared schiff base ligand and its metal complexes are listed in table (1) together
with their elemental analysis data and their physical properties. The elemental analysis data
shows that the synthesized compounds have 1:1 (metal:ligand ) stoichiometry having
molecular formula [Co(H2L).2Cl.2H2O], [Cd(H2L).2Cl.2H2O], [La(H2L).(NO3)3.H2O], and
[Gd(H2L).(NO3)3.H2O]. the Co(II), Cd(II), La(III),and Gd(III) complexes have molar
conductance 1.87,1.95,2.39, and 1.98 S cm2mol-1representing
their non-electrolytic
nature[16] .

Table (1) : Analytical data and some physical properties of Schiff base ligand , (H2L) and its selected metal complexes (1-5)
Molecular formula (M.WT)
colour
Page
M.P
(0c)
Ʌ m
0.9
Elem. Anal .found (calcd. ) %
C
H
O
N
S
Cl
---
M
H2L
114
129
75.10
5.22
4.98
4.22
10.12
---
C20H17NOS (319.38)
(75.20)
(5.37)
(5.00)
(4.38)
(10.01)
(1)[Co(H2L)Cl2.2H2O]
CoC20H17NOS.Cl2.2H2O (485.25)
Greenish
yellow
1.87
49.33
4.35
9.75
2.78
6.54
13.98
12.11
(49.49)
(4.37)
(9.89)
(2.88)
(6.59)
(14.61)
(12.14)
(2)[Cd(H2L)Cl2.2H2O]
White
250> 1.95
43.99
3.88
8.87
2.57
5.88
13.11
20.65
CdC20H17NOS.Cl2.2H2O (538.73)
(44.58)
(3.93)
(8.91)
(2.60)
(5.93)
(13.16)
(20.86)
(3)[La(H2L)(NO3)3 .H2O]
LaC20H17NOS.(NO3)3.H2O (661.43)
Faint
brown
135
165
2.39
1.98
36.11
(36.31)
2.87
2.90
26.55
(26.61) (8.47)
8.44
4.76
(4.83)
---
---
20.33
(20.86)
(4)[Gd(H2L)(NO3)3.H2O]
Pale
35.22
2.77
22.89
8.11
4.55
22.11
GdC20H17NOS.(NO3)3.H2O (680.68) green
(35.28)
(2.81)
(23.10) (8.23)
(4.70)
(23.10)
(5)[La(H2L)(NO3)3 .H2O] (nano)
page
3.39
36.54
2.83
26.88
8.33
4.55
---
20.99
LaC20H17NOS.(NO3)3.H2O (661.43)
(36.31)
(2.90)
(26.61) (8.47)
(4.83)
(20.86)

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1HNMR analysis
After having the HNMR analysis we found that the Schiff base ligand fig. (b) give a
singlet peak at 10.1 ppm which due to the O-H proton and also give a singlet peak at 3.36
ppm due to S-H proton [17]. In addition to amutiplet peaks at 7.01-8.01 ppm due to phenyl
protons. After doing comparison with the metal complex fig.(a) we found that the O-H proton
peak shifted to 10.4 ppm and the S-H proton peak shifted to 3.47 ppm and the phenyl protons
give a multiplet peak at 7 – 8 ppm. This analysis showed that the O-H and S-H groups share
in the complexation with loss of their protons.
Fig.(2)1HNMR spectrum of (a)[Cd(H2L)Cl2.2H2O] complex.
(b) Schiff base ligand H2L.
IR spectra
The IR analysis data listed in table (2). The fig. (3a) showed the IR curve of the Schiff
base ligand. The fig. showed the peaks at 3408, 1590, 697, and 1088 cm-1 due to O-H, C=N,
C-S, and C-O groups [18]. The curves.(b-f) showed the IR curves of the complexes.

Table (2) :Significant IR -spectral bands (cm-1) of Schiff base ligand , (H2L) and its selected metal complexes.
Compd. No.
ᶹO-H
ᶹC=N
ᶹC-S
ᶹC-O
ᶹM-S
ᶹM-O
ᶹNO3
ᶹ
1
ᶹ
2
ᶹ
3
H2L
3408
3381
1590
1592
697
608
1088
1070
---
---
---
---
---
---
[Co(H2L)Cl2.2H2O]
512
698
---
---
[Cd(H2L)Cl2.2H2O]
[La(H2L)(NO3)3 .H2O]
[Gd(H2L)(NO3)3.H2O]
3273
3380
3382
1583
1593
1591
605
615
600
1162
1181
1067
512
479
510
698
676
697
---
---
---
1091
1091
1337 1447
1335 1448
[La(H2L)(NO3)3 .H2O](nano) 3380
1593
615
1181
479
676
1091
1337 1447

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Fig.(3)IR spectrum of:
(a)ligand , H2L .(b) [Co(H2L)Cl2.2H2O] .
(c) [Cd(H2L)Cl2.2H2O]. (d) [La(H2L)(NO3)3 .H2O].
(e) [Gd(H2L)(NO3)3.H2O]. (f)[La(H2L)(NO3)3 .H2O].(nano)

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The curves showed that shift in the peaks of O-H, C-O, C-S groups due to their
sharing in the complexation and that recorded by the M-O, and M-S peaks. The C=N group
doesn't show any shift and this indicate that the azomethine group doesn't participate in
complexation.
Mass spectra
Fig (5) shows the proposed paths of the decomposition steps for ligand .The mass spectrum
of free ligand, H2L, fig. (4) shows that the peak at m/z 319.86 (11.37%) agree with the
molecular formula C26H20N2OS2; 319.38. Also, the spectrum shows different peaks
corresponding to fragments. Their intensity gives the stability of the fragments.
Fig.(4): Mass spectrum of the free ligand H2L.

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OH
C
N
C
H
SH
m/z 319.38 (319.86 ;11.37%)
CH
H2
C
C
N
O
m/z 106.13 (106.99
;34.77 %)
HS
HC
N
m/z 303.38 (303.19 ; 9.6%)
SH
H2
C
C
N
m/z 213.25 (213.16 ; 5.98%)
SH
m/z 110.12(109.13; 10.7 %)
m/z 271.38 (270.05 ; 17.03 %)
C
N
H2
C
C
N
H
m/z 103.13 (104.94; 70.57%)
m/z 195.28 (194.34 ; 2.3% )
m/z 78.12 (77 ; 100 % )
Fig (5): Fragmentation pathway of H2L Schiff base free ligand

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UV – vis electronic spectra and magnetic susceptibility measurement
The magnetic moment values and transition bands are listed in table (3), and the
electronic spectra of the ligand and its complexes are shown in the fig (6).
The Schiff base ligand shows absorption bands around 282 and 375 nm due to π→π*
and n→π*respectively. These bands were shifted to another wave numbers on complex
formation.
Both Cd(ll) and La (lll) complexes are diamagnetic in nature with no d-d transition .
The octahedral structure may be suggested according to all previous data and analysis.
The electronic spectra of Co (ll) complex showed two absorption bands at 582 and 648
4
4
nm assigned to the transition T1g (F) →4T1g(P) and T1g(F)→4A2g(F) , and the magnetic
moment value is 2.72 B.M. confirmed the octahedral structure .
The electronic spectra of Gd complex have no transition bands over 400 nm because f-
ftransition is forbidden. The magnetic moment value is 5.61 B.M. confirmed the octahedral
structure [19].
table (3): UV spectra for ligand , H2L and its complexes.
Compd. No.
H2L
µeff (B.M.)
-
Absorption bands (nm)
π-π*
n-π*
d-d transition
---
282
375
1
2
2.72
210
250
279
309
582, 648
---
Diamagnetic
3
4
Diamagnetic
5.61
227
209
279
279
---
---
5
diamagnetic
227
279
---

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Fig (6): UV spectra for: (a)H2L ligand (b)[Co(H2L)(Cl)2].H2O
(c)[Cd(H2L)(Cl)2].H2O
(d)[La(H2L).(NO3)2]NO3.H2O
(e)[Gd(H2L).(NO3)2]NO3.H2O (f)[La(H2L).(NO3)2]NO3.H2O(nano)
Thermal studies
All data for thermal analysis are listed in table (5).The thermogram of the complex
[Co(H2L).2Cl.2H2O]. (fig.7) Shows that there is an water molecule coordinated with metal in
thecomplex. The first stage of decomposition is starting at 44-1980C the observed mass loss

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at this stage 2.96 % this due to the loss of water molecule. The second stage of decomposition
is from 1990C to 4210C the observed mass loss is 41.69% this is due to the loss of H2O,
HCN, H2S, Cl2, and C4H4. The third stage of decomposition is from 4220C to 5740C. The
observed mass loss is 10.95% this is due to the loss of C4H5. The fourth stage is from 575 0C
to 8470C the observed mass loss is 29.40% is due to the loss of C11H5 leaving 14.95% residue
as CoO. The overall mass loss is observed to be 85.00% which is in well agreement with the
calculated value 84.54%.
The thermogram of the complex [La(H2L).(NO3)3 .H2O] (fig.8) shows that there is an
water molecule coordinated with the metal in
the complex . The first stage of
decomposition is starting at 43-1360C the observed mass loss at this stage 2.29% this due to
the loss of water molecule. The second stage of decomposition is from 1370C to 2390C the
observed mass loss is 7.69% this is due to the loss of CO and HCN. The third stage of
decomposition is from 2390C to 4230C. The observed mass loss is 37.42% this is due to the
loss of 3HNO3, H2S, and C2H2. The fourth stage is from 4240C to 5960C the observed mass
loss is 22.28% is due to the loss ofC10H9. The fifth stage is from 5970 C to 9990C this is due
to the loss of La, leaving 10.93 % residue as 6C. The overall mass loss is observed to be
89.06% which is in well agreement with the calculated value 89.07%.
Table (5) :Thermoanalytical results of metal complexes of Schiff base ligand , H2L .
Complex compd.
TG range Mass loss % obs . Assignment
0 C
(calc.)
(1) [Co(H2L)Cl2.2H2O]
44-198
199-421
422-574
575-847
2.96 (3.71)
41.69(41.63)
10.95(10.94)
29.40(28.26)
Loss of H2O(coord.)
Loss of H2O,HCN,H2S,Cl2 and
C4H4
Loss of C4H5
Loss of C11H5 , Leaving CoO
residue .
Loss of H2O (coord.)
Loss ofCO and HCN.
Loss of3HNO3 ,H2S ,and C2H2.
Loss of C10H9.
85.04(84.54)*
2.29 (2.72)
(2)[La(H2L)(NO3)3 .H2O]
43-136
137-239
239-423
424-999
7.69 (8.31)
37.42(37.65)
22.28(19.53)
leaving 6C , La metal residue
69.68(68.21)*
*Total Mass Loss

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Fig. (7): TGA curve of the [Co(H2L).2Cl.2H2O] complex.
Fig. (8): TGA curve of the [La(H2L).(NO3)3 .H2O] complex.
EDX spectra:
The amount of elements present in percentage level of the metal complexes was
identified by EDX data [20]. EDX spectra is used to calculate the percentage level of the
elements present in the metal complexes like C,O,N,S and La that present in the La(IIl)
complexes (in bulk and nano size) shown in the fig(9). The revealed data are in good
agreement with that of the elemental analysis.

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Fig. (9): EDX spectra of La(IIl) complexes (in bulk and nano size)
Finally, correlation of all techniques used in characterization of the synthesized complexes
gives the proposed structure of the metal complexes as represented in Fig. (10).
H
OH2
H
S
OH2
S
Cl
NO3
M
Cl
M
O3N
N
N
OH2
O
NO3
O
H
H
M=Co or Cd
M=La or Gd
Fig. (10):suggested structure of the complexes

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TEM analysis
Transmission electron microscopy (TEM) can be used to directly image nano particles
at scales approaching a single atom.TEM analysis is performed to examine the size and shape
of the nano particles. The La(III) complex nano particle was fairly uniform in size, spherical
in shape, and with average diameter ranging from 18.66 to 22.68 nm fig. (11).Electron
microscopy analysis allowed confirming visually the observed stability of the obtained nano
complex.
Fig. (11):TEM image of La(III) nano complex
Metal uptake efficiency of ligand, H2L
The important application of the ligand, H2L2 was investigated in removal of Co(II)
ions from aqueous solution to detect the optimal contact time effect on adsorption process
and to know the maximum elimination capacity of the ligand toward the metal ion under
study.
Effect of contact time:
The effect of contact time between the sorbent and the selected metal ions was
examined due to detect the appropriate adsorption time. By the variation of the contact time
from 0 to 150min for constant dose of the sorbent and constant concentration of the metal
ions. It is clear from the result (table 5) fig.(12,13)that as the contact time increases both the
removal percentage of the metal ions and adsorption capacity of the ligand increase until
equilibrium is attained due to availability of active binding sites on the sorbent. The
adsorption process become slower with gradual occupancy of binding sites and finally

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reached equilibrium in about 60 min. Further increase in the contact time had a negligible
effect on the rate of the adsorption amount. [21].
Moreover, the distribution coefficient Kd value can be used as a valuable tool to study
the metal ion mobility. High values of distribution coefficient indicate that the metal has been
retained by the solid phase, while low values indicate that a large fraction of the metal
remains in solution [22].
Table (5): Capacity study of constant dose of sorbent H2L towards Co(II), ions at different
contact time
Adsorbed metal ions
Co(II)
Contact
time (min)
15
Re
%
13.33
qt
Kd
(ml/g)
0.0769
(mg/g)
37.12
30
45
60
75
19.99
25.33
25.33
25.33
55.68
70.53
70.53
70.53
0.1249
0.16963
0.16963
0.16963
30
25
20
15
10
5
0
contact time (min)
0
10
20
30
40
50
60
70
80
Fig (12): Removal efficiency of the ligand towards Co(II) ions at different contact time

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80
70
60
50
40
30
20
10
0
contact time (min)
0
10
20
30
40
50
60
70
80
Fig (13): Adsorption capacity of the ligand towards Co(II) ions at different contact time
Effect of adsorbent dose:
The uptake of the metal ions under study with respect to adsorbent dose was
investigated table(6) In order to determine the smallest amount required for maximum
removal of metal ions fig(14,15). Experimental results showed that the percentage of metal
ions removal increased from 25.33 % to 30.66% for Co(II) ions when the adsorbent dosage
increased from 0.1 to 0.3gm. This may be due to the more adsorption sites available for the
metal ions. Also, the adsorption capacity was increased when the adsorption dosage increased
due to the saturation of adsorption sites as a result to the increase in adsorbent amount and a
constant metal ion concentration and constant volume. Also, this increase in capacity may be
due to the increase in total surface area of the adsorbent.
Table (6): Effect of different doses of sorbent on the adsorption of Co(II), ions at equilibrated contact
time
Different doses of H2L ligand as sorbent at equilibrated contact time
0.1gm
0.2gm
0.3gm
Adsorbed
metal ions
Co(II)
Re
%
qt
Re
%
qt
Re
%
qt
(mg/g)
(mg/g)
(mg/g)
25.33
70.53
28
38.98
30.66
28.46

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35
30
25
20
15
10
5
0
1
2
3
mass of sorbent (gm)
Fig (14): Removal efficiency of the sorbent dosage towards Co(II) ions
80
70
60
50
40
30
20
10
0
1
2
3
mass of sorbent (gm)
Fig (15): Adsorption capacity of the sorbent dosage towards Co(II) ions
Effect of different concentrations of metal ions at equilibrated contact time and specific
weight of ligand
In order to determine the removal activity of the sorbent with increase in the metal ion
concentrations, the uptake of the metal ions under study with respect to specific adsorbent
dose was investigated table(7) fig(16,17). Experimental results showed that the percentage of
metal ions removal decreased when the metal ion concentrations decreased from 0.03 to

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0.003gm. Also, the adsorption capacity was increased when the metal dosage increased due
to the saturation of adsorption sites as a result to the increase in metal ion concentration[23].
Table (7): Effect of different concentrations of metal ions at equilibrated contact time and
specific weight of ligand.
0.003 M/L
0.005 M/L
0.01 M/L
0.02 M/L
0.03 M/L
Adsorbed
metal ion
Re % qe
Re % qe
Re % qe
Re % qe
Re % qe
Co(II)
25.86 55.09
27.27 66.83
25.33 70.53
26.71 129.94 34.59 237.6
40
35
30
25
20
15
10
5
0
0.003
0.005
0.01
0.02
0.03
concentration of metal ion
Fig (16): Removal efficiency of the sorbent dosage towards different concentrations of Co(II)
ions

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250
200
150
100
50
0
0.003
0.005
0.01
0.02
0.03
concentration of metal ion
Fig (17): Adsorption capacity of the sorbent dosage towards different concentrations of
Co(II) ions
In vitro Cytotoxicity Effect on Mammalian Cells
The cell viability (%) was investigated in vitro by MTT-assay using Vero, Caco-2 and
MCF-7 cell. As given in Figs. (18, 19, 20), the free ligand did not exhibit any cytotoxicity on
the cells and the cell viability was around 100(%) for all lower used concentrations. While on
higher concentrations the cell viability was around 90-70(%).
Cytotoxicity Effect of the selected metal complexes on Mammalian Cells
The cytotoxicity effect of the selected metal complexes was assayed using MTT assay
test. It was shown from tables (8, 9, 10) that while the free ligand did not exhibit any activity,
upon complexation the activity increased. The cd(II) complex show the best cytotoxicity
effect on all cells and reduced the cell viability to become 6%, 7.8% and 12% for Vero, Caco-
2 and MCF-7 cell, respectively. Then the La(III) complex which show the viability of Vero,
Caco-2 and MCF-7 cellto be 14, 26 and 27% respectively. Additionally, the relative activities
of the Co(II) complex on the viability of the Mammalian cells at were reported to be 71, 75
and 61%, respectively.

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Table (8) : Cytotoxic effect of free ligand and its metal complexes on the viability of Vero cells
concentration(µg/ml)
Cell viability%
cell line
compound number
10
20
30
40
60
98
80
91
100
87
HL2
100 100 100 100
6
7
90
83
81
79
77
7
76
7
71
6
Vero cells
8
8
8
7
8
9
87
90
63
82
59
80
56
77
53
73
94
37
73
89
14
73
86
10
100 100 100 96
Table (9) : Cytotoxic effect of free ligand and its metal complexes on the viability of Caco-2 cells
concentration(µg/ml)
cell line
compound number
Cell viability%
10
20
30
40
60
96
80
91
100
82
HL2
6
100
100 100 100
97
23
89
20
83
16
79
10
75
8
75
8
75
7
7.8
Caco-2 cells
8
92
74
59
47
40
32
26
9
83
80
99
78
97
76
96
74
92
72
88
70
86
10
100

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Table (10) : Cytotoxic effect of free ligand and its metal complexes on the viability of MCF-7cells
concentration(µg/ml)
cell line
Cell viability%
compound number
10
20
30
40
91
60
87
80
78
100
70
HL2
100 100 98
6
7
91
21
93
94
96
88
19
90
93
95
81
18
84
93
94
77
18
72
92
93
69
16
53
85
91
66
14
39
81
83
61
12
27
77
67
MCF-7 cells
8
9
10
La (nano)
HL2
Co
Gd
Cd
La
La
100
80
60
40
20
0
Cd
Gd
La (nano)
Co
HL2
7
6
5
4
3
2
1
Fig . (18): In vitro cells viability assay against different concentrations of the free ligand and its
metal complexes using Vero cell lines

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La (nano)
HL2
Co
Gd
Cd
La
La
Gd
Cd
La (nano)
80
40
0
Co
HL2
7
6
5
4
3
2
1
Fig . (19) : In vitro cells viability assay against different concentrations of the free ligand and its
metal complexes using Caco-2 cell lines
HL2
La (nano)
Co
Gd
Cd
La
La
100
80
60
40
20
0
Gd
Cd
La (nano)
Co
HL2
7
6
5
4
3
2
1
Fig. (20) : In vitro cells viability assay against different concentrations of the free ligand and its
metal complexes using MCF-7 cell lines
Conclusion
The Schiff base ligand from benzoin and 2-aminothiophenol and its metal complexes
both in bulk and nano size were prepared and characterized using deferent techniques. The
ability of the free ligand to remove different heavy metals was studied. The cytotoxicity
effect of Cd(II) complexusing MTT method exhibited a significant nontoxic behavior and

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higher cell viability on Vero, Caco-2 and MCF-7cellsthan the free ligand itself. The
cytotoxicity results revealed that the Cd(II) complex could become safe to be used as
anticancer agent for Vero, Caco-2 and MCF-7 cells. By examining its pharmacological
activity, we were able to identify new potent and selective anticancer.
Conflict of Interest
The authors have no conflict of interest to declare.
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 A new Schiff base ligand and its metal complexes were prepared.
 La(III) complexes were prepared in bulk and nano size.
 These compounds were characterized by different physicochemical techniques.
 The ability of the free ligand to remove different heavy metals was studied
 We were able to identify new potent and selective anticancer agents
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