Synthesis, spectroscopic, thermal properties, Calf thymus DNA binding and quantum chemical studies of M(II) complexes

Article abstract of DOI:10.1002/aoc.4281

A new series of transition metal complexes of Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) were prepared from the ligand of 5-(4-benzenesulfonic acid azo)-2-thioxo-4-thiazolidinone (H₂L). The M(II) complexes were structurally elucidated by element

Full text of DOI:10.1002/aoc.4281

Received: 3 November 2017
DOI: 10.1002/aoc.4281
Revised: 26 December 2017
Accepted: 26 December 2017
F U L L P A P E R
Synthesis, spectroscopic, thermal properties, Calf thymus
DNA binding and quantum chemical studies of M(II)
complexes
Sh.M. Morgan1
| M.A. Diab2
| A.Z. El‐Sonbati2
1 Environmental Monitoring Laboratory,
Ministry of Health, Port Said, Egypt
2 Chemistry Department, Faculty of
Science, Damietta University, Damietta,
Egypt
A new series of transition metal complexes of Cu(II), Co(II), Ni(II), Mn(II) and
Cd(II) were prepared from the ligand of 5‐(4‐benzenesulfonic acid azo)‐2‐
thioxo‐4‐thiazolidinone (H2L). The M(II) complexes were structurally eluci-
dated by elemental analysis, infrared spectra, spectral studies, thermal analysis,
magnetic measurements and X‐ray diffraction analysis. Elemental analysis and
IR result suggested the ligand was bonded to the metal ions in monobasic/neu-
tral bidentate through the nitrogen atom of the hydrazone group and oxygen
atom of carbonyl group. The bond length, bond angle, HOMO, LUMO and
quantum chemical parameters were calculated to confirm the geometry of the
ligand and the M(II) complexes. In vitro antimicrobial behavior of ligand
(H2L) and its M(II) complexes (1‐5) was screened with targeted bacterial and
fungal strains. Spectroscopic (UV‐vis) technique was employed in order to
study the binding mode and binding strength of the ligand (H2L) and its
M(II) complexes to Calf thymus DNA (CT‐DNA). Intercalation is the most pos-
sible mode of interaction of the ligand (H2L) and its M(II) complexes with CT‐
DNA and the determined binding constants. Molecular docking was used to
predict the binding between the starts (4‐aminobenzenesulfonic acid (start 1)
and 2‐thioxo‐4‐thiazolidinone (start 2)) and tautomers (A‐C) of ligand (H2L)
with the receptors of prostate cancer mutant (PDB code: 2Q7K) and breast can-
cer mutant (PDB code: 3HB5).
Correspondence
M. A. Diab, Chemistry Department,
Faculty of Science, Damietta University,
Damietta, Egypt.
Email: m.adiab@yahoo.com
KEYWORDS
calf thymus DNA binding, geometrical structures, M(II) complexes, molecular docking, thermal
properties
1 | INTRODUCTION
Azo compounds in perspective of rhodanine were
mixed as potential helpful courses of action and can more-
In recent years, heterocyclic azo dyes have found great
success due to their wide applications such as biological
activity, electrical conductivity and optical properties.[1–3]
The chemistry of azo rhodanine compounds has
attracted special interest due to their antimicrobial
activity which includes wide applications in medical
chemistry.[4]
over be used as consistent reagents and in analytical
chemistry.[5,6] The ligands with potential sulfur, oxygen
and nitrogen donors, for example, rhodanine and its
derivatives are entirely intriguing which have gained spe-
cial attention in the most recent decade, not just due to
the structural chemistry and their importance in medical
chemistry, additionally in light these materials are used
Appl Organometal Chem. 2018;e4281.
wileyonlinelibrary.com/journal/aoc
Copyright © 2018 John Wiley & Sons, Ltd.
1 of 25
https://doi.org/10.1002/aoc.4281

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MORGAN ET AL.
as a drugs and they are reported to possess a wide variety
of antimicrobial activities against bacteria and fungi. They
DNA (CT‐DNA) was acquired from SRL (India). Metal
salts; Cu(CH3COO)2. H2O, Co(CH3COO)2. 4H2O,
Ni(CH3COO)2. 4H2O, Mn(CH3COO)2. 4H2O and
Cd(CH3COO)2. 2H2O (Sigma Aldrich). Organic solvents
were spectroscopic pure from BDH included ethanol,
are additionally turned into
a helpful model for
bioinorganic forms, which has numerous biochemical
and pharmacological application and also used in antiox-
idants.[7–9]
diethyl
ether,
dimethylsulfoxide
(DMSO)
and
Azo rhodanine derivatives have played an important
role in the development of coordination chemistry as they
readily form stable complexes with most transition
metals.[10–15] The variety of coordination modes of azo
rhodanine derivatives has been demonstrated in a number
of complexes. Also, azo rhodanine and its derivatives con-
tain hetero atoms were used as anti‐corrosion agents.[16]
The present study describes the preparation and chela-
tion behavior of ligand (H2L) towards of Cu(II), Co(II),
Ni(II), Mn(II) and Cd(II) acetate. The structure of the
studied complexes is elucidated using elemental analysis,
IR, UV–Vis spectra, magnetic moment, molar conduc-
tance measurements, X‐ray diffraction analysis and ther-
mal analysis. The antimicrobial activity of ligand (H2L)
and its Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) complexes
were studied and compared with the standard antibacte-
rial and antifungal drugs. Calf thymus DNA binding of
the ligand (H2L) and its Cu(II), Co(II), Ni(II), Mn(II)
and Cd(II) complexes were studied and discussed. The
thermodynamic parameters of the ligand (H2L) and its
Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) complexes were
studied using Coats–Redfern and Horowitz–Metzger
methods.
dimethylformamide (DMF).
2.1 | Preparation of the ligand (H2L)
2.1.1 | Diazotization
4‐Aminobenzenesulfonic acid was dissolved in hydrochlo-
ric acid at room temperature then cooled at 0‐5 °C and
maintained at this temperature, solution of sodium nitrite
in water was added dropwise under continuous stirring
and the mixture was stirred at 0‐5 °C for 1 h [1,17]. The
resulting diazonium solution was used directly in the cou-
pling step.
2.1.2 | Coupling
The coupling of 2‐thioxothiazolidin‐4‐one was dissolved
in pyridine and cooled at 0‐5 °C in an ice bath. The above
diazonium solution was added to the stirred coupling 2‐
thioxothiazolidin‐4‐one solution at 0‐5 °C over 30 min.
The precipitated solid was filtered with suction, washed
by water and then vacuum dried. The rough product
was finally purified by recrystallized to give ligand (H2L)
(Scheme 1). Analytical found for ligand (H2L)
C9H7N3O4S3: C, 33.99; H, 2.18; N, 13.19 and S, 30.22 (cal-
culated: C, 34.07; H, 2.21; N, 13.25 and S, 30.28). Yield:
2 | EXPERIMENTAL
(84%), dark yellow, melting point 290 °C. IR (KBr, υmax
,
2‐Thioxothiazolidin‐4‐one and 4‐aminobenzenesulfonic
acid were bought from Sigma Aldrich Chemical Co., Inc.
and used without further purification. The calf thymus
cm‐1): 3487‐3163 (N―H str.), 3104, 2967 (C―H str.
asym.), 2849 (C―H str. sym.), 1550 (phenyl ring), 1712
(C=O), 1603 (C=N‐N‐ hydrazone), 1118 (N‐N), 1369
SCHEME 1 The formation mechanism
of ligand (H2L)

MORGAN ET AL.
3 of 25
(S=O asym.), 1162 (S=O sym.), 826 (CS), 751 (N―H
wag); 1H NMR (DMSO‐d6, δ, ppm): 11.00 (1H, NH
hydrazone, exchangeable with D2O), 7.18–8.90 (d, Ar,
4H), ~ 4.38 (s, OH, 1H, benzenesulfonic, exchangeable
with D2O), 13C NMR (DMSO‐d6, δ, ppm): 165 (C=O),
193 (C=S), 143 (C=N―NH), 113‐127 (C‐atom of benzene
ring).
2.2.3 | Complex [Ni(HL)(O2CCH3)(H2O)2]
4H2O (3)
Grayish brown, m.p. > 300 °C, Yield 71%. Analytical
found for C11H21N3O12S3Ni (541.69): C, 24.18; H, 2.36;
N, 7.67; S, 17.64; Ni, 10.93%. Calculated C, 24.37; H,
2.40; N, 7.75; S, 17.72; Ni, 10.84%, in agreement with the
formula of the complex used for thermogravimetric anal-
ysis (TGA) (below‐mentioned). IR (KBr, υmax, cm‐1): 1645
(C=O), 3418 (OH, benzenesulfonic, H2O), 1601 (C=N‐N‐,
hydrazone), 1165 (N‐N), 1223 (S=O asym.), 1121 (S=O
sym.), 829 (CS), 751 (N―H wag), 760 (OH rocking water),
1494 (COO‐ sym.), 1342 (COO‐ asym.), 559 (O‐Ni), 434 (N‐
Ni). Molar conductance (10‐3 M, DMSO): 9.56 Ω‐1 cm2 mol‐1.
2.2 | Preparation of the metal(II)
complexes
The metal(II) complexes were prepared by refluxing a hot
ethanolic solution containing ligand (H2L) was mixed
with a hot ethanolic solution of M(CH3COO)2.nH2O
(1 mmol) and refluxed on a water bath for ~ 6‐8 hrs.
The colored complexes were filtered and washed with
ethanol and finally dried in vacuum desiccator over
anhydrous CaCl2. The yield obtained was 67‐78%
(Figure S1).
μeff. = 2.83 B.M.
2.2.4 | Complex [Mn(HL)(O2CCH3)(H2O)2]
3H2O (4)
Brown, m.p. > 300 °C, Yield 67%. Analytical found for
C11H19N3O11S3Mn (519.93): C, 25.19; H, 2.40; N, 7.87; S,
18.39; Mn, 10.64%. Calculated C, 25.39; H, 2.50; N, 8.08;
S, 18.46; Mn, 10.56%, in agreement with the formula of
the complex used for thermogravimetric analysis (TGA)
(below‐mentioned). IR (KBr, υmax, cm‐1): 1610 (C=O),
3350 (OH, benzenesulfonic, H2O), 1560 (C=N‐N‐,
hydrazone), 1168 (N‐N), 1228 (S=O asym.), 1125 (S=O
sym.), 829 (CS), 751 (N―H wag), 763 (OH rocking water),
1438 (COO‐ sym.), 1324 (COO‐ asym.), 505 (O‐Mn),
460 (N‐Mn). Molar conductance (10‐3 M, DMSO):
12.45 Ω‐1 cm2 mol‐1. μeff. = 5.29 B.M.
2.2.1 | Complex [Cu(HL)(O2CCH3)(H2O)2]
2H2O (1)
Pale gray m.p. > 300 °C, Yield 74%. Analytical found for
C11H17N3O10S3Cu (510.546): C, 25.82; H, 2.44; N, 8.17; S,
18.69; Cu, 12.50%. Calculated C, 25.86; H, 2.55; N, 8.23; S,
18.80; Cu, 12.45%, in agreement with the formula of the
complex used for thermogravimetric analysis (TGA)
(below‐mentioned). IR (KBr, υmax, cm‐1): 1651 (C=O),
3441 (OH, benzenesulfonic, H2O), 1599 (C=N‐N‐,
hydrazone), 1158 (N‐N), 1217 (S=O asym.), 1128 (S=O
sym.), 833 (CS), 751 (N―H wag), 729 (OH rocking
water), 1529 (COO‐ sym.), 1365 (COO‐ asym.), 560 (O‐
Cu), 470 (N‐Cu). Molar conductance (10‐3 M, DMSO):
6.88 Ω‐1 cm2 mol‐1. μeff. = 1.89 B.M.
2.2.5 | Complex [Cd(H2L)(OCOCH3)2] H2O
(5)
Dark orange, m.p. > 300 °C, Yield 78%. Analytical found
for C13H15N3O9S3Cd (565.41): C, 27.40; H, 2.16; N, 7.37;
S, 16.89; Cd, 20.33%. Calculated C, 27.59; H, 2.30; N,
7.43; S, 16.98; Cd, 19.88%, in agreement with the formula
of the complex used for thermogravimetric analysis
(TGA) (below‐mentioned). IR (KBr, υmax, cm‐1): 1671
(C=O), 3432, 3190, 3090 (NH, hydrazone, H2O), 1601
(C=N‐N‐, hydrazone), 1120 (N‐N), 1232 (S=O asym.),
1121 (S=O sym.), 829 (CS), 751 (N―H wag), 754 (OH
rocking water), 1538 (COO‐sym.), 1328 (COO‐ asym.),
2.2.2 | Complex [Co(HL)(O2CCH3)(H2O)2]
3H2O (2)
Dark brown, m.p. > 300 °C, Yield 68%. Analytical found
for C11H19N3O11S3Co (523.933): C, 25.10; H, 2.36; N,
7.77; S, 18.19; Co, 11.44%. Calculated C, 25.19; H, 2.48;
N, 8.02; S, 18.32; Co, 11.25%, in agreement with the for-
mula of the complex used for thermogravimetric analysis
(TGA) (below‐mentioned). IR (KBr, υmax, cm‐1): 1652
(C=O), 3399 (OH, benzenesulfonic, H2O), 1603 (C=N‐
N‐, hydrazone), 1186 (N‐N), 1319 (S=O asym.), 1121
(S=O sym.), 829 (CS), 751 (N―H wag), 795 (OH
rocking water), 1544 (COO‐ sym.), 1432 (COO‐ asym.),
567 (O‐Co), 480 (N‐Co). Molar conductance (10‐3 M,
DMSO): 8.25 Ω‐1 cm2 mol‐1. μeff. = 3.69 B.M.
1
561 (O‐Cd), 455 (N‐Cd);. H NMR (DMSO‐d6, δ, ppm):
10.09 (1H, NH hydrazone, exchangeable with D2O),
7.12–8.53 (d, Ar, 4H),
~
4.36 (s, OH, 1H,
benzenesulfonic, exchangeable with D2O); Molar con-
ductance (10‐3 M, DMSO): 13.50 Ω‐1 cm2 mol‐1. μeff.
=
diamagnetic.

4 of 25
MORGAN ET AL.
The activities of ligand and its M(II) complexes were
compared with penicillin and miconazole as standard
drugs against bacteria and fungi, respectively.
2.3 | DNA binding experiments
The binding properties of ligand (H2L) and its M(II)
complexes (1‐5) to calf thymus DNA (CT‐DNA) are
studied using UV‐Vis absorption spectroscopy tech-
nique.[18,19] Absorption spectra are carried out using
1 cm quartz cuvette at room temperature by fixing the
concentration of the prepared compounds (1 × 10‐3 mol
L‐1), while progressively increasing the concentration
of calf thymus DNA (CT‐DNA). The intrinsic
binding constant (Kb) of the prepared compounds with
calf thymus DNA was determined by the following
equation 1.[17–19] In plots of [DNA]/(єa–єf) versus
[DNA], Kb is given by the ratio of the slope to the
intercept.
2.5 | Instrumentation
Elemental microanalyses of the separated compounds
for C, H, N and S were analyzed in the Microanalytical
Center, Cairo University, Egypt. Infrared spectra were
recorded as KBr discs using a Perkin‐Elmer 1340 spec-
trophotometer. The 1H and 13C‐NMR spectra were
obtained on a JEOL FX 900Q Fourier transfer spectrom-
eter with DMSO‐d6 as the solvent and tetramethylsilane
(TMS) as an internal reference. Mass spectra were
recorded by the EI technique at 70 eV using MS‐5988
GS‐MS Hewlett‐Packard. Ultraviolet‐visible (UV‐Vis)
spectra of the compounds were recorded in nujol mulls
using a Unicom SP 8800 spectrophotometer. The con-
ductance was achieved using Sergeant Welch Scientific
Co., Skokie, IL, USA. Electron spin resonance (ESR)
measurements of powdered samples were recorded at
room temperature using an X‐band spectrometer utiliz-
ing a 100 kHz magnetic field modulation with diphenyl
picrylhydrazyle (DPPH) as a reference material. The
magnetic moment of the prepared solid complexes
was determined at room temperature using the
Gouy's method. Mercury(II) (tetrathiocyanato)cobalt(II),
[Hg{Co(SCN)4}], was used for the calibration of the
Gouy tubes. Diamagnetic corrections were calculated
from the values given by Selwood[20] and Pascal's con-
stants. Magnetic moments were calculated using the
½DNAꢀ
½DNAꢀ
1
À
Á
À
Á
À
Á
¼
þ
(1)
εa−εf
εb−εf
Kb εa−εf
where єa is the molar extinction coefficient observed for
the Aobs/[compound] at the given DNA concentration, єf
is the molar extinction coefficient of the free compound
in solution, [DNA] is the concentration of CT‐DNA in
base pairs and єb is the molar extinction coefficient of
the compound when fully bond to DNA.
2.4 | Biological activity assay
The method of agar well diffusion was adopted for this
examination.[17–19] The antifungal activities of the
investigated compounds are scanned against three local
fungal types (Aspergillus niger, Fusarium oxysporum
and the yeast Candida albicans) on DOX agar medium
and the antibacterial activities are scanned on nutrient
agar medium against three local Gram positive bacte-
rial species (Bacillus cereus, Staphylococcus aureus and
Enterococcus faecalis) and three local Gram negative
bacterial species (Escherichia coli, Klebsiella pneumoniae
and Pseudomonas aeruginosa). The concentrations of
every solution of compound were 50, 100 and 150 μg/ml
in dimethylformamide (DMF). Utilizing a sterile cork
borer (10 mm diameter), wells was made in medium
of agar plates previously seeded with the test microor-
ganism. 200 μL of every compound was applied in
every well. The agar plates were kept at 4 °C for at
least 30 min to allow the diffusion of the compound
to agar medium. The plates were then incubated at
37 °C or 30 °C for bacteria and fungi, respectively.
The diameters of inhibition zone were specified after
24 hour and 7 days for bacteria and fungi, respectively,
taking the consideration of the control values (DMF).
equation, μeff. = 2.84[TcM ]
coor. 1/2. Thermal studies were
computed on Simultaneous Thermal Analyzer (STA)
6000 system using thermogravimetric analysis (TGA)
method. Thermal properties of the samples were
analyzed in the temperature range from 30 to 800 °C
at the heating rate of 10 °C/min under dynamic nitrogen
atmosphere. X‐ray diffraction analysis of compounds
powder forms was recorded on X‐ray diffractometer
analysis in the range of diffraction angle 2θo
=
4–80o.[14,17] This analysis was carried out using CuKα
radiation (λ = 1.540598 Ả). The applied voltage and
the tube current are 40 kV and 30 mA, respectively.
The diffraction peaks in powder spectra are indexed
and the lattice parameters are determined with the aid
of CRYSFIRE computer program.[21]
Docking calculations were carried out on receptors of
prostate cancer mutant (PDB code: 2Q7K) and breast can-
cer mutant (PDB code: 3HB5) protein models. The
MMFF94 Force field was used for energy minimization
of molecules using Docking Server.[22–24]

MORGAN ET AL.
5 of 25
2.6 | Theoretical concepts
0:95λ
1=2 cosθ
ξ ¼
(9)
2.6.1 | Computational method of the
β
molecular structures
The equation uses the reference peak width at angle
(θ), where is wavelength of X‐ray radiation
A computational study of the investigating compounds is
made to examine their reactivities and to evaluate geo-
metrical parameters. Perkin Elmer ChemBio3D software
and Perkin Elmer ChemBio Draw software are used to
draw the structures.[14,19] The structures of the ligand
and its metal complexes are optimized by HF method
with 3‐21G basis set. Optimization was performed with-
out any symmetry constraint using the default conver-
gence criteria provided in the software.
λ
(1.540598 Å) and β1/2 is the width at half maximum of
the reference diffraction peak measured in radians. The
dislocation density, δ, is the number of dislocation lines
per unit area of the crystal. The value of δ can be calcu-
lated from the average particle diameter (ξ) by equa-
tion[17,19]
:
1
ξ2
The quantum chemical parameter of ligand (H2L) and
its complexes such as the absolute electronegativities (χ) is
calculated by:
δ ¼
(10)
The values of estimated lattice parameters (a, b, c, α, β
and γ), inter‐planar spacing (d) and miller indices (hkl) for
ligand (H2L) and Mn(II) complex (4) are determined by
using CHEKCELL program.[25]
−ðEHOMO þ ELUMO
Þ
;
χ ¼
(2)
2
where EHOMO is the highest occupied molecular orbital
energy and is ELUMO the lowest unoccupied molecular
orbital energy.
3 | RESULTS AND DISCUSSION
The absolute hardness (η), absolute softness (σ),
chemical potential (Pi), global softness (S), global electro-
philicity (ω), and additional electronic charge (ΔNmax) are
3.1 | The structure of the ligand and its
complexes
calculated as follows[19]
:
The ligand (H2L) and its complexes (1‐5) are found to be
stable in air, colored, soluble in coordinated solvents and
high melting points. The elemental analysis confirm that
the complexes have a molar ratio of 1 M(II):1 ligand
stoichiometry as presented in Table 1. The molar conduc-
E
LUMO−EHOMO
η ¼
;
(3)
2
tance values of the complexes were measured in 10‐3
M
1
σ ¼ ;
η
(4)
(5)
dimethylsulfoxide (DMSO) solution at room temperature
(see Section 2). The low molar conductance values reveal
the non‐electrolytic nature of the complexes.[26] The mag-
netic moment of metal(II) complexes (1‐4) was estimated
at room temperature and has a paramagnetic nature and
octahedral geometry, whereas the Cd(II) complex (5) is
tetrahedral and diamagnetic. Based on the spectroscopic
analysis, the speculated formulas of M(II) complexes can
be designed as shown in Table 1 and Figure S1.
The mass spectrum of ligand (H2L) exhibits a parent
molecular ion peak at m/z = 317 which is equal to the
formula weight of the ligand [C9H7N3O4S3] (Figure S2).
The peak at m/z 220 formed from ligand (H2L) through
the removal of SO4H group (structure I) as shown in
Scheme S1. This fragment undergoes further fragmentation
by the removal of sulpher atom giving molecular ion peak
at m/z = 188 that represent [C9H6N3S] (structure II). The
spectrum shows molecular ion peaks at m/z = 112 and
83 corresponding to the [C3H2N3S] (structure III) and
[C3HNS] (structure IV) fragments, respectively. The
Pi ¼ −χ;
1
2η
S ¼
ω ¼
;
(6)
(7)
Pi2
;
2η
Pi
ΔNmax ¼ − :
(8)
η
2.6.2 | X‐ray diffraction
The average crystallite size (ξ) can be calculated from the
XRD pattern according to Debye–Scherrer equation[17]
:

6 of 25
MORGAN ET AL.
TABLE 1 Elemental analysis of ligand (H2L) and its M(II) complexes (1‐5)
Exp. (calcd.)%
Compound
C
H
N
S
M
H2L
33.99 (34.07)
25.82 (25.86)
25.10 (25.19)
24.18 (24.37)
25.19 (25.39)
27.40 (27.59)
2.18 (2.21)
2.44 (2.55)
2.36 (2.48)
2.36 (2.40)
2.40 (2.50)
2.16 (2.30)
13.19 (13.25)
8.17 (8.23)
7.77 (8.02)
7.67 (7.75)
7.87 (8.08)
7.37 (7.43)
30.22 (30.28)
18.69 (18.80)
18.19 (18.32)
17.64 (17.72)
18.39 (18.46)
16.89 (16.98)
‐
[Cu(HL)(O2CCH3)(H2O)2] 2H2O (1)
[Co(HL)(O2CCH3)(H2O)2] 3H2O (2)
[Ni(HL)(O2CCH3)(H2O)2] 4H2O (3)
[Mn(HL)(O2CCH3)(H2O)2] 3H2O (4)
[Cd(H2L)(OCOCH3)2] H2O (5)
12.50 (12.45)
11.44 (11.25)
10.93 (10.84)
10.64 (10.56)
20.33 (19.88)
TABLE 2 The IR bands (cm‐1) of ligand (H2L) and its metal(II) complexes
Compounda
υ(CO)
υ(NH) hydrazone
υ(C=N‐N‐), (N‐N)
δ(H2O) rocking
υ(M‐O)
υ(M‐N)
υ(COO‐)
H2L
1712
1651
1652
1645
1610
1671
3487‐3163
1603, 1118
1599, 1158
1603, 1186
1601, 1165
1560, 1168
1601, 1120
‐
‐
‐
‐
1
2
3
4
5
‐
729
795
760
763
754
560
567
559
505
561
470
480
434
460
455
1529, 1365
1544, 1432
1494, 1342
1438, 1324
1538, 1328
‐
‐
‐
3432‐3090
aNumbers as given in Table 1.
FIGURE 1 The starts (start 1 & start 2) and tautomers (A‐C) of ligand (H2L) (green in (a) and grey in (b)) in interaction with receptor of
prostate cancer mutant (PDB code: 2Q7K)

MORGAN ET AL.
7 of 25
information gathered from mass spectrum data agrees well
with elemental analysis data.
= 541.69 undergoes fragmentation to a stable peak at m/
z = 218, 90 and 76 by losing 6H2O + CH3CO2Ni +
SO4H, C3HS2N2 and N atoms, respectively, (structures
I‐III) for Ni(II) complex (3) (Scheme S3). The ion of
m/z = 565.41 undergoes fragmentation to a stable peak
at m/z = 429.41, 236, 105 and 76 by losing H2O +
2CH3COO, SO3H + Cd, C3HS2ON and N2H atoms,
respectively, (structures I‐IV) for Cd(II) complex (5)
(Scheme S4).
The electron impact mass spectra of Cu(II) complex
(1), Ni(II) complex (3) and Cd(II) complex (5) are
shown in Schemes S2‐S4. The ion of m/z = 510.546
undergoes fragmentation to a stable peak at m/z =
438.546, 316, 235, 90 and 76 by losing 4H2O, CH3CO2Cu,
SO3H, C3HS2ON2, and N atoms, respectively, (structures
I‐V) for Cu(II) complex (1) (Scheme S2). The ion of m/z
FIGURE 2 The starts (start 1 & start 2) and tautomers (A‐C) of ligand (H2L) (green in (a) and grey in (b)) in interaction with receptor of
breast cancer mutant (PDB code: 3HB5)
TABLE 3 Energy values obtained in docking calculations of the starts (start 1 & start 2) and tautomers (A‐C) of ligand (H2L) with the
receptors of prostate cancer mutant (PDB code: 2Q7K) and breast cancer mutant (PDB code: 3HB5)
Estimated Free energy Estimated inhibition Electrostatic
of binding (kcal/mol) constant (Ki) (μM) Energy (kcal/mol) Energy (kcal/mol) surface
Total intercooled Interact
Receptor Compounda
2Q7K
3HB5
Start 1
Start 2
Azo keto form (A)
Azo enol form (B)
Keto hydrazone
form (C)
‐5.45
‐4.20
‐4.54
‐2.28
‐6.79
101.74
829.57
470.91
21.23
‐0.06
‐0.03
‐0.05
‐0.09
‐0.03
‐6.04
‐4.20
‐5.94
‐3.29
‐8.36
335.761
267.831
498.618
500.213
482.531
10.51
Start 1
Start 2
Azo keto form (A)
Azo enol form (B)
Keto hydrazone
form (C)
‐5.51
‐4.44
‐6.86
‐6.99
‐7.30
179.01
554.27
9.35
7.48
4.44
‐0.02
‐0.06
+0.02
‐0.12
‐0.04
‐5.71
‐4.44
‐7.77
‐7.82
‐7.86
447.819
326.23
755.279
801.237
743.353
aSymbols as given in Scheme 1.

8 of 25
MORGAN ET AL.
1H NMR spectra of ligand (H2L) and Cd(II) complex
Scheme 1. The infrared spectrum of hydrazone based on
a substituted rhodanine and in particular the position of
the carbonyl stretching vibrations, has been of
(Figures S3–S6) show singlet peak at 11.00 ppm assigned
to NH proton of C=N‐NH, hydrazone group, (exchange-
able with D2O, Figure S4) for ligand (H2L) and singlet
peak at ~ 10.09 ppm assigned to NH proton of C=N‐NH,
hydrazone group, (exchangeable with D2O, Figure S6)
for Cd(II) complex. The downfield shift of this singlet
peak (C=N‐NH, of H2L) is due to the intramolecular
hydrogen bonding between NH and O atom of rhodanine
ring (Scheme 1).
The 13C NMR spectrum of ligand (H2L) shows the sig-
nals at 143, 193 and 165 ppm attributed to carbon atoms
of C=N―NH, C=S and C=O groups, respectively. The
carbon atoms of benzene ring appear in the range of
113‐127 ppm (Figure S7). The disappearance of the signal
for the C―OH proton in the azo enol form (Scheme 1B)
indicated that H2L is found in solution as keto hydrazone
form (Scheme 1C). Some azo structures were found in the
keto hydrazone form in the crystal form by El‐Sonbati
et al.[14]
In context of the broad differences in the substituent
effects (e.g., substituent constants for different positions
and sulfonyl group); it might be possible to tune the
strength of the hydrogen bond effectively by linking the
hydrogen bonding site to a reaction center through a con-
jugated spacer and by changing the charge state of the
reaction center in the solution. An intramolecular hydro-
gen bridge linking of the carbonyl groups to the NH‐
moiety of the hydrazone group was found to be a charac-
teristic feature of this compound class. The six membered
intramolecular hydrogen bonding ring is possible
forming a keto hydrazone tautomer as showed in
FIGURE 3 Histogram of the free energy of binding (kcal/mol) for
starts (start 1 & start 2) and tautomers (A‐C) of ligand (H2L) with the
receptors of prostate cancer mutant (PDB code: 2Q7K) and breast
cancer mutant (PDB code: 3HB5)
FIGURE 4 The optimized structures for tautomers (A‐C) of
ligand (H2L)

MORGAN ET AL.
9 of 25
TABLE 4 The bond lengths and bond angles for keto hydrazone
form (C) of ligand (H2L)
considerable importance in establishing that the com-
pound exists exclusively in the keto hydrazone form.
The solid state IR spectrum of the synthesized ligand
shows intense carbonyl band at 1712 cm‐1[27] consistent
with a keto hydrazone form. It can be suggested that
the ligand exists as keto hydrazone form with extensive
six‐membered intramolecular hydrogen bonding and this
has been confirmed by a number of previous published
reports of keto hydrazone analogues.[28–30] Another typi-
cal feature of the free ligand is the existence of an NH
vibration around 3487‐3163 cm‐1 which affords proof of
the H‐bonded hydrazone structure in the solid state.[31,32]
Bond lengths (Å)
O(19)‐H(26)
C(15)‐H(25)
C(14)‐H(24)
C(12)‐H(23)
C(11)‐H(22)
N(4)‐H(21)
N(1)‐H(20)
C(10)‐C(15)
C(14)‐C(15)
C(13)‐C(14)
C(12)‐C(13)
C(11)‐C(12)
C(10)‐C(11)
C(6)‐C(5)
Bond angles (o)
H(26)‐O(19)‐S(16)
H(21)‐N(4)‐C(5)
H(21)‐N(4)‐C(3)
C(5)‐N(4)‐C(3)
0.939
1.103
1.103
1.104
1.103
1.006
1.045
1.343
1.343
1.345
1.345
1.342
1.343
1.377
1.375
1.363
1.788
1.489
1.271
1.787
1.272
1.231
1.572
1.21
109.446
120.949
124.135
114.916
113.407
116.22
C(10)‐S(16)‐O(19)
C(10)‐S(16)‐O(18)
C(10)‐S(16)‐O(17)
O(19)‐S(16)‐O(18)
O(19)‐S(16)‐O(17)
O(18)‐S(16)‐O(17)
H(25)‐C(15)‐C(10)
H(25)‐C(15)‐C(14)
C(10)‐C(15)‐C(14)
C(15)‐C(10)‐C(11)
C(15)‐C(10)‐S(16)
C(11)‐C(10)‐S(16)
H(22)‐C(11)‐C(12)
H(22)‐C(11)‐C(10)
C(12)‐C(11)‐C(10)
H(24)‐C(14)‐C(15)
H(24)‐C(14)‐C(13)
C(15)‐C(14)‐C(13)
H(23)‐C(12)‐C(13)
H(23)‐C(12)‐C(11)
C(13)‐C(12)‐C(11)
C(14)‐C(13)‐C(12)
C(14)‐C(13)‐N(1)
C(12)‐C(13)‐N(1)
H(20)‐N(1)‐C(13)
H(20)‐N(1)‐N(9)
C(13)‐N(1)‐N(9)
C(6)‐N(9)‐N(1)
118.002
82.863
1
In the H NMR spectrum of the ligand measured in
96.035
DMSO‐d6 (Figure S3), the hydrazone proton appears as
a singlet at 11.00 ppm, which corresponds to NH proton
resonance of the hydrazone form.[33] The above results
suggest that the ligand exists in the keto hydrazone form
120.822
120.487
119.039
120.473
119.079
120.4
1
in the solid state, and the obtained IR, mass, H NMR
spectra and elemental analytical data agree well with
the formulae of the ligand.
The following features for the prepared complexes are
observed. The important IR bands are listed in Table 2.
N(4)‐C(5)
C(3)‐N(4)
120.52
S(2)‐C(3)
119.084
120.55
i. In all complexes bands at 3487–3163 cm‐1 are
observed, attributed to different probabilities: (a) it
is due to either free OH or NH (b) bonded‐OH group
or ‐NH group or (c) due to the presence of coordi-
nated water molecules.
ii. Upon coordination, it is noteworthy that the peak at
1712 cm‐1 for ligand attributed to υ(C=O) vibration
was shifted to lower wavenumber.[14]
iii. In addition, the IR spectrum of the ligand revealed a
sharp peak at 1118 cm‐1 belonging to υ(N‐N) vibra-
tion as shown in Figure S8 which shifted to higher
frequency range of 1158‐1186 cm‐1 after complexa-
tion in all metal complexes (1‐4), suggesting that
the hydrazone nitrogen participates in the complex-
ation mode. This supported by the disappearance of
the broad υ(NH…..O) peak in all complexes (1‐4),
indicating deprotonation of the hydrazone proton
(C=N‐N‐) prior to coordination of nitrogen to the
metal ion.
iv. The acetate complexes (1‐4) have two strong bands
corresponding to υas (COO‐) and υs(COO‐) with a dif-
ferences between frequencies of 112‐164 cm‐1. This
difference confirms the bidentate nature of the coor-
dinated acetate.[14,34]
C(6)‐S(2)
C(13)‐N(1)
C(10)‐S(16)
C(6)‐N(9)
120.365
118.224
121.105
120.671
120.614
118.584
120.802
118.609
123.479
117.912
115.272
115.738
128.989
123.235
111.958
129.379
118.662
113.147
127.861
118.992
97.086
N(1)‐N(9)
C(3)‐S(8)
C(5)‐O(7)
S(16)‐O(19)
S(16)‐O(18)
S(16)‐O(17)
1.672
1.468
1.465
C(6)‐C(5)‐N(4)
C(6)‐C(5)‐O(7)
N(4)‐C(5)‐O(7)
C(5)‐C(6)‐S(2)
C(5)‐C(6)‐N(9)
S(2)‐C(6)‐N(9)
v. IR spectra of complexes (1‐4) show broad troughs
in the region 3350 ‐ 3440 cm‐1 indicative of
υ(OH) of coordinated water as confirmed by ther-
mal and elemental analysis. The rocking mode of
coordinated water is also observed in the range of
729‐795 cm‐1.[35]
C(3)‐S(2)‐C(6)
N(4)‐C(3)‐S(2)
102.892
129.638
127.471
N(4)‐C(3)‐S(8)
S(2)‐C(3)‐S(8)

10 of 25
MORGAN ET AL.
vi. In complex (5), the CO and NH of hydrazone,
hydrogen bonding interaction upon complex forma-
tion. The new additional bands observed at υas
(COO‐) and υs(COO‐) with a differences between fre-
quencies of 210 cm‐1. This difference confirms the
monodentate nature of the coordinated acetate.[18]
stretching frequencies observed at ~ 1712 and 3487‐
3163 cm‐1 for the free ligand are shifted to lower fre-
quencies of 1671 and 3432‐3090 cm‐1 in case of
Cd(II) complex. This is due to the modification of
FIGURE 5 HOMO and LUMO molecular orbital for tautomers (A‐C) of ligand (H2L)
TABLE 5 The calculated quantum chemical parameters for the tautomers of ligand (H2L)
Quantum
chemical
Tautomera
parameters
Azo keto form (A)
Azo enol form (B)
Keto hydrazone form (C)
EHOMO (eV)
ELUMO (eV)
χ (eV)
‐3.378
‐3.018
3.198
0.180
5.556
‐3.198
2.778
28.409
17.767
‐2.399
‐2.257
2.328
‐6.210
‐2.111
4.1605
2.050
0.488
‐4.161
0.244
4.223
2.030
η (eV)
σ (eV)‐1
0.071
14.085
‐2.328
7.042
Pi (eV)
S (eV)‐1
ω (eV)
38.166
32.789
ΔNmax
aSymbols as given in Scheme 1.

MORGAN ET AL.
11 of 25

12 of 25
MORGAN ET AL.
vii. Coordination of the oxygen atom of carbonyl group
and nitrogen atom of the hydrazone group in the
chelate ring is supported by the appearance of new
bands at 505‐567 and 434‐480 cm‐1 and are assigned
to υ(M‐O) and υ(M‐N), respectively.
mutant (PDB code: 3HB5) [36,37]. All docked compounds
of starts (1 and 2) and tautomers (A‐C) of ligand (H2L)
were represented in Figures 1 and 2. Also, the current
ligand–receptor interactions were analyzed on the basis
of energy values as described in Table 3. 2D plot
curves of docking with the starts (1 and 2) and tauto-
mers (A‐C) of ligand (H2L) are shown in Figures S9
and S10.
3.2 | Molecular docking study
The results showed a possible arrangement between
the starts (start 1 & start 2) and tautomers (A‐C) of
ligand (H2L) with the receptors of prostate cancer
mutant (PDB code: 2Q7K) and breast cancer mutant
(PDB code: 3HB5). The docking study showed a
In this present study, we used molecular docking
between the starts (4‐aminobenzenesulfonic acid (start
1) and 2‐thioxo‐4‐thiazolidinone (start 2)) and tautomers
(A‐C) of ligand (H2L) with the receptors of prostate
cancer mutant (PDB code: 2Q7K) and breast cancer
FIGURE 6 The optimized structures of metal(II) complexes

MORGAN ET AL.
13 of 25
favorable interaction between the starts (1 and 2) and
tautomers (A‐C) of ligand (H2L) with the receptors of
prostate cancer mutant (PDB code: 2Q7K) and breast
cancer mutant (PDB code: 3HB5) (Figures 1 and 2).
According to the results obtained in this study, the starts
and tautomers (A‐C) of ligand (H2L) show best interac-
tion with receptor of breast cancer mutant (PDB code:
3HB5) than receptor of prostate cancer mutant (PDB
code: 2Q7K). From the data summarized in Table 3, it
was found that all of the tested compounds were
interacted with the protein receptors through a hydrogen
bond interaction. The values of interaction energies
revealed that the keto hydrazone form (C) of ligand
(H2L) is the most stable interaction than the other com-
pounds (starts, azo keto form (A) and azo enol form (B))
and the free energy of binding of keto hydrazone form
(C) is ‐6.79 and ‐7.30 kcal/mol for receptors of prostate
cancer mutant (PDB code: 2Q7K) and breast cancer
mutant (PDB code: 3HB5), respectively, as shown in
Figure 3. In addition to the keto hydrazone form (C)
FIGURE 7 The highest occupied
molecular orbital (HOMO) and the lowest
unoccupied molecular orbital (LUMO) of
metal(II) complexes

14 of 25
MORGAN ET AL.
TABLE 7 The calculated quantum chemical parameters for
complexes
of ligand (H2L) shows the best interaction with
receptor of breast cancer mutant (PDB code: 3HB5) than
the receptor of prostate cancer mutant (PDB code:
2Q7K).
HB plot curve indicates that the starts (start 1 & start
2) and tautomers (A‐C) of ligand (H2L) bind to the pro-
teins with hydrogen bond interactions and decomposed
interaction energies in kcal/mol were exist between the
starts (1 and 2) and tautomers (A‐C) of ligand (H2L) with
the receptors of prostate cancer mutant (PDB code: 2Q7K)
and breast cancer mutant (PDB code: 3HB5) as shown in
Figures S11 and S12.
Quantum
chemical
parameters
Complexa
(1)
(2)
(3)
(4)
(5)
EHOMO (eV)
ELUMO (eV)
χ (eV)
‐1.975
‐1.782
1.879
‐2.468
‐2.200
2.334
0.134
7.463
‐2.334
3.731
20.327
17.418
‐5.929
‐2.821
4.375
1.554
0.644
‐4.375
0.322
6.159
2.815
‐8.175
‐6.334
7.255
0.921
1.086
‐7.255
0.543
28.587
7.881
‐5.147
‐2.104
3.626
1.522
0.657
‐3.626
0.329
4.320
2.383
η (eV)
σ (eV)‐1
0.097
10.363
‐1.879
5.181
Pi (eV)
S (eV)‐1
ω (eV)
18.284
19.466
3.3 | Geometrical structures of ligand and
its M(II) complexes
ΔNmax
aNumbers as given in Table 1.
The optimized structures of the tautomers (azo keto form
(A), azo enol form (B) and keto hydrazone form (C)) of
ligand (H2L) are shown in Figure 4. The bond lengths
and bond angles for ligand (H2L) are listed in Table 4.
The HOMO and LUMO molecular orbital for tautomers
(A‐C) of ligand (H2L) is presented in Figure 5. Both the
highest occupied molecular orbital (HOMO) and lowest
unoccupied molecular orbital (LUMO) are the main
orbital takes part in chemical stability. The chemical
potential (Pi), absolute hardness (η) and global electrophi-
licity (ω) were calculated from the HOMO and LUMO
value of the tautomers (A‐C) of ligand (H2L) as given in
the Table 5. The reactivity of the tautomers of azo keto
form (A), azo enol form (B) and keto hydrazone form
(C) of ligand (H2L) can be predicted by considering the
minimum electrophilicity value. The value of ω for azo
keto form (A), azo enol form (B) and keto hydrazone form
(C) was found to be 28.409, 38.166 and 4.223 eV, respec-
tively. The calculations indicated that the keto hydrazone
form (C) is less electrophilicity value, so the keto
hydrazone form (C) is highly stable than other tautomers
(azo keto form (A) and azo enol form (B)). The computed
net charges on active centers for the tautomers (A‐C) of
ligand (H2L) are listed in Table 6, it is found that the most
negative charges in ligand are N(1) and O(7) for keto
hydrazone form (C) that makes it react stronger with the
metal ion.
Tables S1‐S5. It is seen from the Tables S1‐S5 that the
bond angles around the metal ion in case of Cu(II), Co(II),
Ni(II) and Mn(II) complexes are in the range of 88‐107°
suggesting distorted octahedral geometry for Cu(II),
Co(II), Ni(II) and Mn(II) complexes.
3.4 | Magnetic moment, electronic spectra
and ESR spectrum of Cu(II) complex
The cobalt(II) complex (2) is paramagnetic and shows an
affective magnetic moment of 3.69 B.M. The electronic
spectrum of Co(II) exhibit 12820 cm‐1 [4T1g(F)→4T2g(F)
4
(υ1)], 16200 cm‐1 [4T1g(F)→ A2g(F)(υ2)] and 22739 cm‐1
[4T1g(F)→ 4T1g(P)(υ3)] transitions which are characteristic
of octahedral geometry.[19] The ligand field splitting
energy (10Dq), interelectronic repulsion parameter (B`),
covalency factor (β) and ligand field stabilization energy
(LFSE) for the octahedral Co(II) complex are calculated
and found to be 3627 cm‐1, 48.4 cm‐1, 0.04 and 10.39 kcal
mol‐1, respectively. The υ2/υ1 = 1.26, occur in the usual
range expected for octahedral Co(II) complexes.
The nickel(II) complex (3) is paramagnetic and shows
an affective magnetic moment of 2.83 B.M. which is
within the range expected for two unpaired electron.[19]
Its electronic spectrum shows three bands 10525
The optimized structures, HOMO and LUMO molecu-
lar orbital of the complexes are shown in Figures 6 and 7.
The quantum chemical parameters of the complexes were
also collected from their optimized geometry and pre-
sented in the Table 7. According to electrophilicity value,
compound having minimum electrophilicity will have
maximum stability, so Ni(II) complex (3) is more stable
than the other complexes (1, 2 and 4). The bond lengths
and bond angles for metal(II) complexes are listed in
3
3
[3A2g(F) → T2g(F)(υ1)], 20000 [3A2g(F) → T1g(F)(υ2)]
and 25000 cm‐1 [3A2g(F) → T1g(P)(υ3)] transitions.[38]
3
The water molecules occupied on z‐axis of Cartesian coor-
dinate made them hexa coordination around Ni(II) ion.
Absence of any band below 10000 cm‐1 ruled out the pos-
sibility of tetrahedral geometry. Various ligand field
parameters i.e. 10Dq, B, β, ligand field stabilization energy
(LFSE) (kcal mol‐1) and υ2/υ1 are calculated and found to

MORGAN ET AL.
15 of 25
be 10525 cm‐1, 895 cm‐1, 0.86, 36.17 and 1.90, respectively.
The nephelauxetic parameter (β) is obtained by using the
relation: β = B(complex)/Bo(free ion), where B is the
Racah interelectronic repulsion parameter for complex is
less than one suggesting considerable amount of covalent
character of the metal‐ligand bonds. The lowering in the B
value from the free ion value of Ni(II) suggests covalent
character in the bonding. The energy separation between
3A2g(F) and 3T2g(F) is equal to 10Dq and the value of 10Dq
in octahedral of Ni(II) complexes vary between 6400 and
12700 cm‐1, depending on the position of the ligand in
the spectrochemical series. The 10Dq value of the present
Ni(II) complex is 10525 cm‐1 which is the characteristic of
the octahedral geometry.
The room temperature magnetic moment value of
Mn(II) complex (4) is found to be 5.29 B.M. which is
low compared to the spin‐only value for high‐spin Mn(II)
complexes. The low value can be attributed to the pres-
ence of Mn(III) species.[19] The weak spectral bands in
Mn(II) complex observed at 17240, 21275 and 24290 cm‐1
are attributed to A1g → T1g (G), A1g → T2g (G) and
6A1g → 4Eg transitions, respectively.[39] The observed mag-
netic moment value is slightly lower than high spin com-
plex (6.0 B.M.) expected for five unpaired electron with an
octahedral environment around Mn(II) ion.[40] The mag-
netic moment of the Cd(II) complex does not show any
vibration peak in the visible region which indicates the
diamagnetic behavior of the complexes.
6
4
6
4
FIGURE 8 X‐ray diffraction patterns of powder forms for ligand (H2L) and its metal(II) complexes

16 of 25
MORGAN ET AL.
The room temperature magnetic moment value of the
Cu(II) complex (1) is 1.89 B.M. indicate the nature of the
complex. The value corresponds to one unpaired electron
and the complex may be considered as octahedral geome-
try. Copper(II) complex showed three absorption bands at
2
2
16450 cm‐1 [2B1g → A1g], 19790 cm‐1 [2B1g → B2g] and
TABLE 8 Crystallographic data of the ligand (H2L)
Peak no.
2θobs. (°)
dobs. (Å)
2θcalcd. (°)
dcalcd. (Å)
h k l
1
10.1916
14.6321
15.1496
16.0206
16.6964
19.5329
21.9537
22.4038
23.5659
25.2295
26.353
8.6725
6.0490
5.8435
5.5278
5.3055
4.5410
4.0454
3.9652
3.7722
3.5271
3.3792
3.1654
3.0746
2.9974
2.9463
2.8291
2.6717
2.5279
2.4604
2.3566
2.3146
2.1876
2.1739
1.8788
1.7749
10.2247
14.4044
15.1542
16.0023
16.7469
19.5556
21.959
8.6445
6.1441
5.8418
5.5340
5.2896
4.5358
4.0445
3.9633
3.7694
3.5264
3.3768
3.1630
3.0721
2.9958
2.9460
2.8307
2.6692
2.5308
2.4614
2.3582
2.3099
2.1885
2.1742
1.8792
1.7753
1 0 1
2 0 1
1 0 2
3 0 0
2 0 2
2 1 1
0 1 2
3 1 0
4 0 2
3 0 3
4 1 1
2 1 3
4 0 2
3 1 3
1 0 4
6 0 1
5 1 1
5 1 3
6 1 2
3 0 4
6 0 2
7 1 0
2 1 5
6 1 5
1 3 2
2
3
4
5
6
7
8
22.4146
23.5838
25.2345
26.372
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
28.1689
29.0189
29.7827
30.3114
31.5991
33.5144
35.4829
36.4895
38.1579
38.8778
41.2334
41.5064
48.4079
51.4441
28.1907
29.0429
29.7996
30.3148
31.5812
33.5472
35.441
36.4747
38.1309
38.9594
41.2162
41.5004
48.3982
51.4313
TABLE 9 Crystallographic data of the Mn(II) complex (4)
Peak no.
2θobs. (°)
dobs. (Å)
2θcalcd. (°)
dcalcd. (Å)
h k l
1
2
3
4
5
6
7
8
9.4261
9.3750
8.6246
8.0542
7.7258
6.2680
5.5466
4.3500
3.5418
9.4032
9.3977
8.6400
8.0542
7.6968
6.2660
5.5421
4.3489
3.5445
1 0 1
2 0 0
1 1 0
1 0 1
2 1 0
3 0 1
1 1 2
2 1 2
10.2483
10.9762
11.4443
14.1184
15.9659
20.3995
25.1232
10.2300
10.9787
11.4876
14.1228
15.9788
20.4049
25.1034

MORGAN ET AL.
17 of 25
26795 cm‐1 [2B1g → 2Eg] transitions with octahedral geom-
etry with 2B1g. The ESR spectrum is characteristic to octa-
hedral geometry.[18] The g‐value has been calculated by
the method published earlier.[18,19] The value of G = (gll‐
2.0023)/(g⊥‐2.0023) which measure the exchange interac-
tion between the copper centers. If the value of G > 4,
the exchange interaction is negligible but the G < 4 value
suggest considerable interaction between the solid com-
plex. The value of G in the complex is G > 4, suggesting
that there is no interaction between the copper centers
and the unpaired electron is present in the dx2‐y2 orbital.
It is used to determined the bonding parameters for Cu(II)
ion in various ligand field environments. In‐plane σ‐bond-
ing parameter, α2 is related to gll and g⊥ as follows:[18] α2
= All/0.036 + (gll – 2.0023) + 3/7(g⊥ – 2.0023) + 0.04. The
α2 value of 0.5 indicates complete covalent bonding, while
that of 1.0 suggests complete ionic bonding. The observed
value (0.61) indicates that the complex is predominantly
covalent in character. The out‐of‐plane π‐bonding (γ2)
and in‐plane π‐bonding (β2) parameters are calculated.
In this work, the copper(II) complex show γ2 (1.07) and
β2 (1.18), indicating the ionic character of the out‐of‐plane
π‐bonding.[19]
The Kll, K⊥ and K are used as a measure of cova-
lency.[41] For an ionic environment K =1 and for a cova-
lent environment K < 1. In the present work, the
complex has K (0.70), indicating the covalent nature of
the bonding. In the case of pure σ‐bonding, Kll ≈ K⊥
=
0.77, whereas Kll < K⊥ = 0.77 implies considerable in‐
plane π‐bonding, while for out‐of plane π‐bonding Kll >
K⊥ = 0.77. For the present complex, the observed order
K⊥ (0.72) > Kll (0.65) implies a greater contribution from
in‐plane π‐bonding than for out‐of‐plane π‐bonding in
metal‐ligand bonding. The f value (185 cm‐1) show that
the Cu(II) complex (1) has an octahedral geometry, and
this is further confirmed by the Symons plot.[42]
3.5 | X‐ray diffraction analysis
The X‐ray diffraction (XRD) patterns powder forms for
ligand (H2L) and its M(II) complexes (1‐5) are presented
FIGURE 9 TGA curves of ligand (H2L) and its metal(II) complexes

18 of 25
MORGAN ET AL.
in Figure 8. The XRD of ligand (H2L) and Mn(II) complex
(4) show many diffraction peaks which indicate the poly-
crystalline phases. The XRD of complexes (1‐3 & 5) show
a broad peak in the range of 2θo = 20‐25o indicating a
completely amorphous structures. The average crystallite
size (ξ.) is calculated and found to be 53 and 51 nm for
ligand (H2L) and Mn(II) complex (4), respectively. The
value of dislocation density (δ) is found to be 3.560 ×
10−4 and 3.845 × 10−4 nm−2 for ligand (H2L) and Mn(II)
complex (4), respectively.
The values of estimated lattice parameters (a, b, c, α,
β and γ), inter‐planar spacing (d) and miller indices (hkl)
for ligand (H2L) and Mn(II) complex (4) which estimated
by CRYSFIRE are listed in Tables 8 and 9, respectively.
The calculated crystal system for ligand (H2L) is found
to be monoclinic with space group P21/m (Table 8).
The estimated lattice parameters are found to be
16.9909 Å, 5.6786 Å, 11.7935 Å, 90.00°, 102.28° and
90.00° for a, b, c, α, β and γ, respectively. For Mn(II)
complex (4) is polycrystalline with monoclinic crystal
system with space group P21/n (Table 9). The estimated
lattice parameters are found to be 17.7627 Å, 9.1010 Å,
9.9131 Å, 90.00°, 103.39° and 90.00° for a, b, c, α, β and
γ, respectively.
3.6 | Thermal analysis
3.6.1 | Thermal analysis of ligand (H2L)
The thermal properties of ligand (H2L) and its M(II) com-
plexes were characterized on the basis of thermogravimet-
ric analysis (TGA) method in the temperature range 30–
800 °C (Figure 9). The effect of temperature and the per-
centage of loss of mass of ligand (H2L) and its M(II) com-
plexes are listed in Table 10. The experimental weight loss
values for the ligand (H2L) and M(II) complexes are in
good agreement with the calculated values.
The ligand (H2L) was thermally stable up 80 °C.
Decomposition of the ligand (H2L) began at 80 °C and fin-
ished at 345 °C. The thermal decomposition of this ligand
TABLE 10 Thermal analysis data of the ligand (H2L) and its complexes
Temp.
Found mass
Total mass loss
Residue Found
(calcd.) %
Compounda range (°C) loss (calcd.) % Found (calcd.) % Assignment
H2L
80‐345
345‐800
63.98 (63.72)
36.02 (36.28)
100 (100)
Loss of C6H6N2O4S
Loss of C3HNS2
‐
(1)
40‐110
7.46 (7.05)
77.27 (77.37)
Loss of two water molecules in outside of the
coordination sphere.
CuO + 3C atoms
22.73 (22.63)
110‐ 420
46.64 (46.81)
Loss of two coordinated water molecules,
coordinated acetate group and C3H2N3S2
Loss of C3H4O3S
420‐800
40‐118
23.17 (23.51)
10.94 (10.31)
(2)
83.12 (83.41)
Loss of three water molecules in outside of the
coordination sphere.
CoO + C atom
16.88 (16.59)
118‐438
34.90 (35.50)
Loss of two coordinated water molecule,
coordinated acetate group and CHNS2
Loss of C5H4O3S
438‐560
560‐800
27.66 (27.48)
9.62 (10.12)
Loss of C2HN2
(3)
(4)
(5)
40‐120
12.31 (13.29)
83.85 (83.99)
76.97 (77.13)
67.27 (68.80)
Loss of four water molecules in outside of the
coordination sphere.
Loss of two coordinated water molecule,
coordinated acetate group and C3H2N3S2
Loss of C5H4O3S
NiO + C atom
16.15 (16.01)
120‐480
44.46 (44.12)
480‐800
40‐112
27.08 (26.58)
10.56 (10.39)
Loss of three water molecules in outside of the
coordination sphere.
Loss of two coordinated water molecule,
coordinated acetate group and C3H2N2S2
Loss of C2H4O3NS
MnO + 4C atoms
23.03 (22.87)
112‐320
43.04 (43.28)
320‐800
40‐80
23.37 (23.46)
3.25 (3.18)
Loss of one water molecule in outside of the
coordination sphere.
CdO + 4C atoms
32.73 (31.20)
80‐406
406‐800
39.99 (41.39)
24.03 (24.23)
Loss of two coordinated acetate groups and C3H2NS2
Loss of C2H5N2O3S
aNumbers as given in Table 1.

MORGAN ET AL.
19 of 25
occurred completely in two steps, with weight loss of
found 63.98% (calcd. 63.72%) which was consistent with
the loss of C6H6N2O4S and the second step at the temper-
ature range 345‐800 °C suits to loss of C3HNS2 (found
36.02%; calcd. 36.28%).
23.17%; calcd. 23.51%) and CuO as a residue contami-
nated with three carbon atoms (found 22.73%; calcd.
22.63%).
The TGA curve of the complex [Co(HL)(O2CCH3)
(H2O)2] 3H2O (2) showed four stages, the first stage at
temperature range 40‐118 °C this stage was correspond-
ing to the loss of three water molecules in outside of
the coordination sphere with a weight loss amounted to
10.94% (calcd. 10.31%). The second stage at 118‐438 °C
corresponded to the loss of two coordinated water mole-
cule and coordinated acetate group, further decomposi-
tion of a part of the ligand (CHNS2) (found 34.90%;
calcd. 35.50%). The third stage at 438‐560 °C was corre-
sponding to the loss of a part of the ligand (C5H4O3S)
(found 27.66%; calcd. 27.48%) and the fourth stage,
which was the final stage, at 560‐800 °C related to loss
of part of the ligand (C2HN2) (found 9.62%; calcd.
10.12%). Cobalt oxide was remained as a residue
3.6.2 | Thermal analysis of complexes
Complex
[Cu(HL)(O2CCH3)(H2O)2]
2H2O
(1)
decomposed at three stages, the first stage at temperature
range 40‐110 °C which related to loss of two water mole-
cules in outside of the coordination sphere (found 7.46%;
calcd. 7.05%),[18] the second stage at 110‐420 °C which
related to loss of two coordinated water molecules and
coordinated acetate group, further decomposition of a
part of the ligand (C3H2N3S2) (found 46.64%; calcd.
46.81%), the third stage at 420‐800 °C and corresponded
to the loss of a part of the ligand (C3H4O3S) (found
FIGURE 10 Coats–Redfern (CR) method of ligand (H2L) and its metal(II) complexes

20 of 25
MORGAN ET AL.
contaminated with one carbon atom with mass percent
of 16.88% (calcd. 16.59%).
was corresponding to the loss of three water molecules
in outside of the coordination sphere with a weight loss
amounted to 10.56% (calcd. 10.39%). The second stage
at 112‐320 °C corresponded to the loss of two coordi-
nated water molecule and coordinated acetate group, fur-
ther decomposition of a part of the ligand (C3H2N2S2)
(found 43.04%; calcd. 43.28%) and the third stage at
320‐800 °C was corresponding to the loss of a part of
the ligand (C2H4O3NS) (found 23.37%; calcd. 23.46%).
MnO was remained as a residue contaminated with four
carbon atoms with mass percent of 23.03% (calcd.
22.87%).
Cd(II) complex [Cd(H2L)(OCOCH3)2] H2O (5)
decomposed in three stages. The first starts at 40‐80 °C
and corresponded to the loss of one water molecule in
outside of the coordination sphere (found 3.25%; calcd.
3.18%). The second and third stages represented the loss
of two coordinated acetate groups, further decomposition
The TGA curve of the complex [Ni(HL)(O2CCH3)
(H2O)2] 4H2O (3) decomposed at three stages, the first
stage at temperature range 40‐120 °C which related to loss
of four water molecules in outside of the coordination
sphere (found 12.31%; calcd. 13.29%)[1], the second stage
at 120‐480 °C was related to loss of two coordinated water
molecule and coordinated acetate group, further decom-
position of a part of the ligand (C3H2N3S2) (found
44.46%; calcd. 44.12%) and the third stage at 480‐800 °C
and corresponded to the loss of a part of the ligand
(C5H4O3S) (found 27.08%; calcd. 26.58%). NiO as a residue
contaminated with one carbon atom (found 16.15%; calcd.
16.01%).
The thermal decomposition of [Mn(HL)(O2CCH3)
(H2O)2] 3H2O (4) proceeded with three degradation
stages. The first stage at temperature range 40‐112 °C
FIGURE 11 Horowitz‐Metzger (HM) method of ligand (H2L) and its metal(II) complexes

MORGAN ET AL.
21 of 25
of a part of the ligand (C3H2NS2) at 80‐406 °C (found
39.99%; calcd. 41.39%) and loss of a part of the ligand
(C2H5N2O3S) at 406‐800 °C (found 24.03%; calcd.
24.23%) leaving CdO as a residue with four carbon atoms
(found 32.73%; calcd. 31.20%).
The calculated values of Ea, ΔS*, ΔH* and ΔG* for
ligand (H2L) and its M(II) complexes are summarized in
Table 11. The kinetic data obtained from the two methods
are comparable and can be considered in good agreement
with each other.[17–19]
From the results obtained, the following remarks can
be pointed out:
3.7 | Kinetic studies
1. The value of the thermal activation energy of decom-
position (Ea) for ligand (H2L) and its M(II) complexes
(1‐5) was calculated by the Coast‐Redfern and Horo-
witz‐Metzger methods and found that the M(II) com-
plexes are less Ea values than ligand (H2L), this trend
can be attributed to the loss of water molecules in out-
side of the coordination sphere in the complexes.[2]
2. According to the values of the thermal activation
energy of decomposition (Ea), the order of Ea value
of the octahedral complexes is Ni(II) > Cu(II) > Co(II)
> Mn(II). This sufficiently agreeing with geometrical
structures results of electrophilicity which discussed
above where compound having minimum electrophi-
licity will have maximum stability (Figure 12).
The kinetic parameters such as the thermal activation
energy of decomposition (Ea), enthalpy (ΔH*), entropy
(ΔS*) and Gibbs free energy change of the decomposition
(ΔG*) are evaluated graphically by employing the Coast‐
Redfern and Horowitz‐Metzger methods.[43,44]
The entropy (ΔS*) and the thermal activation energy
of decomposition (Ea) were calculated.[17,18] The enthalpy
(ΔH*) and Gibbs free energy of decomposition (ΔG*) were
calculated from ΔH* = Ea − RT and ΔG = ΔH* − T ΔS*,
respectively. The thermodynamic data obtained with the
Coast‐Redfern and Horowitz‐Metzger methods for ligand
(H2L) and its M(II) complexes are shown in Figures 10
and 11.
TABLE 11 Thermodynamic data of the thermal decomposition of ligand (H2L) and its complexes
Temp.
range
(°C)
Parameters
Ea (kJ mol−1
Correlation
coefficient
(r)
Compounda
Method
)
ΔS* (J mol‐1 K‐1)
ΔH* (kJ mol−1
)
ΔG* (kJ mol−1
)
H2L
114‐160
160‐425
CR
HM
CR
80.6
82.5
48.9
56.7
‐85.8
‐84.8
‐214
‐197
77.1
79.1
44.2
52.0
112
114
165
163
0.99846
0.99162
0.99174
0.98724
HM
(1)
(2)
(3)
(4)
(5)
115‐385
385‐460
CR
HM
CR
36.3
45.0
28.4
29.4
‐233
‐211
‐12.1
‐14.6
32.0
40.6
279
288
154
151
287
289
0.99231
0.99089
0.98659
0.98738
HM
142‐420
420‐544
CR
HM
CR
25.2
34.2
137
148
‐261
‐239
‐130
‐100
20.5
29.6
130
142
165
162
228
218
0.9876
0.99218
0.99005
0.9906
HM
120‐428
428‐533
CR
HM
CR
38.8
46.4
292
284
‐231
‐213
‐102
‐112
34.3
41.8
286
277
160
158
363
370
0.98451
0.99916
0.99872
0.99387
HM
122‐307
307‐522
CR
HM
CR
24.2
32.3
45.6
56.1
‐237
‐232
‐240
‐220
20.1
28.1
39.9
50.4
136
141
205
202
0.99638
0.99457
0.99212
0.99584
HM
120‐406
406‐572
CR
HM
CR
22.0
22.6
121
127
‐268
‐261
‐146
‐132
175
181
115
120
161
158
226
221
0.99502
0.99533
0.99471
0.99271
HM
aNumbers as given in Table 1.

22 of 25
MORGAN ET AL.
3. The positive sign of ΔG* for the investigated com-
plexes reveals that the free energy of the final residue
is higher than that of the initial compound, and all
the decomposition steps are non spontaneous pro-
cesses. Also, the values of the activation, ΔG*
increases significantly for the subsequent decomposi-
tion stages of a given complex.[45]
4. The negative ΔS* values for the decomposition steps
indicate that all studied complexes are more ordered
in their activated state.[17]
3.8 | DNA binding study by absorption
spectral
As the ligand (H2L) and its Cu(II), Co(II), Ni(II), Mn(II)
and Cd(II) complexes possess biologically important
rhodanine moiety in them, it would be interesting to
investigate their binding with DNA molecule. The bind-
ing of the ligand (H2L) and its metal complexes with Calf
thymus DNA (CT‐DNA) was studied using UV‐Vis
absorption spectroscopy technique. UV‐Vis absorption
spectroscopy is the one of the most common and useful
ways to investigate the interaction of ligand and/or metal
complexes with DNA. Transition metal complexes can
bind to DNA via both covalent and/or non‐covalent inter-
actions.[46] From the absorption spectra of the ligand
(H2L) and its metal complexes in the absence and pres-
ence of increasing amounts of CT‐DNA showed
hypochromism effect and red shift where absorption spec-
tra decrease with increasing concentration of Calf thymus
DNA (CT‐DNA).
FIGURE 12 Histogram of the global electrophilicity (ω) and the
thermal activation energy of decomposition (Ea) where (a) Coats–
Redfern (CR) method and (b) Horowitz‐Metzger (HM) for
octahedral complexes (1‐4)
The intrinsic binding constants (Kb) of the ligand
(H2L) and its M(II) complexes (1‐5) with CT‐DNA were
determined by equation 1 (Figure 13). The intrinsic bind-
ing constants (Kb) values were calculated and listed in
Table 12. From Table 12, the intrinsic binding constant
(Kb) values show that the complexes have stronger bind-
ing ability to the CT‐DNA than their ligand. Also, it was
found that the complex (3) is the highest value of Kb
which indicated that the Ni(II) is highly binding with
CT‐DNA and this may be due to the lower ionic radius
with compared to other complexes.
3.9 | Antimicrobial studies
Antibacterial and antifungal activities of ligand (H2L) and
its metal complexes (1‐5) were tested against, three local
Gram positive bacteria (Bacillus cereus, Staphylococcus
aureus and Enterococcus faecalis), three local Gram nega-
tive bacteria (Escherichia coli, Klebsiella pneumoniae and
Pseudomonas aeruginosa) and three local fungi (Aspergil-
lus niger, Fusarium oxysporum and the yeast Candida
FIGURE 13 The plots of [DNA]/(εa
concentration for the ligand (H2L) and its metal(II) complexes
− εf) versus DNA
albicans) and the results were recorded in Tables 13 and
14. Co(II), Ni(II) and Mn(II) complexes have no antibacte-
rial activity against all the tested bacteria. The ligand (H2L)

MORGAN ET AL.
23 of 25
TABLE 12 The intrinsic binding constants (Kb) of ligand (H2L) and its complexes
Compounda
Kb (M‐1)
H2L
(1)
(2)
(3)
(4)
(5)
8.50 × 104
5.86 × 104
3.69 × 105
4.02 × 105
4.93 × 105
9.69 × 104
aNumbers as given in Table 1.
TABLE 13 Antibacterial activity data of ligand (H2L) and its complexes. The results were recorded as the average diameter of inhibition
zone (mm)
Gram positive bacteria
Gram negative bacteria
Conc.
(μg/ml)
Bacillus
cereus
Staphylococcus
aureus
Enterococcus
faecalis
Escherichia
coli
Klebsiella
pneumoniae
Pseudomonas
aeruginosa
Compounda
H2L
50
100
150
1
1
1
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
(1)
50
100
150
‐ve
2
3
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
(2)
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
(3)
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
(4)
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
(5)
50
100
150
1
1
2
1
1
1
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
0.5*
1*
1*
‐ve
‐ve
‐ve
Penicillin
50
100
150
1
3
3
2
2
2
1.46
1.86
2.2
1
3
3
‐ve
‐ve
‐ve
0.87
1.06
1.4
aNumbers as given in Table 1.
*Indicate significant different value from that of penicillin.
has antibacterial activity against Bacillus cereus (inhibition
zone = 1 mm at all the concentrations), Cu(II) complex
has antibacterial activity against Bacillus cereus (inhibition
zone = 2 and 3 mm at concentrations = 100 and 150 μg/
ml, respectively) and Cd(II) complex has antibacterial
activity against Bacillus cereus (inhibition zone = 1, 1
and 2 mm at concentrations = 50, 100 and 150 μg/ml,
respectively) and has antibacterial activity against Staphy-
lococcus aureus (inhibition zone = 1 mm at all the concen-
trations). Also, Cd(II) complex has antibacterial activity
against Klebsiella pneumoniae (inhibition zone = 0.5, 1
and 1 mm at concentrations = 50, 100 and 150 μg/ml,
respectively). The results showed that Cd(II) complex
is very good antibacterial agents against Klebsiella
pneumoniae (Table 13). Where it was found that the Cd(II)
complex is more active than penicillin which is used as the
antibacterial standard drug against Klebsiella pneumoniae.
The antifungal activity results of the ligand (H2L) and
its metal complexes (1‐5) were investigated against
Aspergillus niger, Fusarium oxysporum and Candida
albicans and listed in Table 14. It was found that the
ligand (H2L) and its metal complexes (1‐5) have neither
antifungal nor anticandidal activities except Mn(II) com-
plex (4) that has antifungal activity against Fusarium
oxysporum (inhibition zone = 0.6 mm at concentration
= 150 μg/ml).[47]

24 of 25
MORGAN ET AL.
TABLE 14 Antifungal activity data of ligand (H2L) and its com-
plexes. The results were recorded as the average diameter of inhi-
bition zone (mm)
ACKNOWLEDGEMENT
The authors would like to thank Prof. Dr. M.I. Abou‐
Dobara, Botany Department, Faculty of Science, Damietta
University, Egypt for his help during testing antimicrobial
activity.
Conc.
Aspergillus Fusarium
Candida
Compounda (μg/ml) niger
oxysporum albicans
H2L
(1)
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
ORCID
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
Sh.M. Morgan http://orcid.org/0000-0002-8921-4894
M.A. Diab http://orcid.org/0000-0002-9042-1356
A.Z. El‐Sonbati http://orcid.org/0000-0001-7059-966X
(2)
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
REFERENCES
[1] A. Z. El‐Sonbati, M. A. Diab, Sh. M. Morgan, J. Mol. Liq. 2017,
225, 195.
(3)
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
[2] N. A. El‐Ghamaz, M. A. Diab, A. Z. El‐Sonbati, Sh. M. Morgan,
O. L. Salem, Chem. Pap. 2017, 71, 2417.
(4)
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
0.6
‐ve
‐ve
‐ve
[3] N. A. El‐Ghamaz, A. Z. El‐Sonbati, M. A. El‐Mogazy, J. Mol.
Liq. 2017, 248, 556.
(5)
50
100
150
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
‐ve
[4] M. I. Abou‐Dobara, A. Z. El‐Sonbati, Sh. M. Morgan, World J.
Microbiol. Biotechnol. 2013, 29, 119.
[5] W. I. Stephen, A. Townshend, Anal. Chim. Acta 1965, 33, 257.
Miconazole
50
100
150
1
3
4
2
3
3
1.1
1.3
1.7
[6] G. Galán Alfonso, J. L. Gómez Ariza, Microchem. J. 1981, 26,
574.
[7] K. Sudo, Y. Masumoto, M. Matsushima, M. Fujwara, K. Konno,
K. Shimotohno, S. Shigerta, T. Yokora, Biochem. Biophys. Res.
Comm. 1997, 238, 643.
aNumbers as given in Table 1.
4 | CONCLUSION
[8] B. T. Moorthy, S. Ravi, M. Srivastava, K. K. Chiruvella, H.
Hemlal, O. Joy, S. C. Raghavan, Bioorg. Med. Chem. Lett. 2010,
20, 6297.
The ligand (H2L) acts monobasic bidentate forming six
membered chelating rings towards the metal ions. The
XRD studies show that the ligand (H2L) and Mn(II) com-
plex (4) are polycrystalline with monoclinic crystal struc-
ture. The keto hydrazone form (C) of ligand (H2L) shows
the best interaction with receptor of breast cancer mutant
(PDB code: 3HB5) than the receptor of prostate cancer
mutant (PDB code: 2Q7K). It was found that the Cu(II)
and Cd(II) complexes have antimicrobial activity against
studied bacteria when compared with ligand (H2L). The
interaction of the ligand (H2L) and its M(II) complexes
(1‐5) with Calf thymus DNA (CT‐DNA) was explored by
absorption spectroscopy. The intrinsic binding constant
(Kb) of ligand (H2L) and its M(II) complexes (1‐5) with
CT‐DNA obtained from UV‐vis absorption spectral stud-
ies were 5.86 × 104, 3.69 × 105, 4.02 × 105, 4.93 × 105,
9.69 × 104 and 8.50 × 104 M‐1, respectively, which revealed
that the complexes could interact with CT‐DNA. It was
found that the Ni(II) complex (3) is the highest value of
intrinsic binding constant (Kb) which indicated that the
Ni(II) is highly binding with CT‐DNA and this may be
due to the lower ionic radius with compared to other
complexes.
[9] M. Sortino, P. Delgado, S. Juárez, J. Quiroga, R. Abonĺa, B.
Insuasty, M. Nogueras, L. Rodero, F. M. Garibotto, R. D. Enriz,
S. A. Zacchino, Bioorg. Med. Chem. 2007, 15, 484.
[10] A. Z. El‐Sonbati, A. A. M. Belal, M. S. El‐Gharib, Sh. M.
Morgan, Spectrochim. Acta A 2012, 95, 627.
[11] A. Z. El‐Sonbati, M. A. Diab, A. A. M. Belal, Sh. M. Morgan,
Spectrochim. Acta A 2012, 99, 353.
[12] A. Z. El‐Sonbati, M. A. Diab, A. A. El‐Bindary, Sh. M. Morgan,
Inorg. Chim. Acta 2013, 404, 175.
[13] A. Z. El‐Sonbati, M. A. Diab, A. A. El‐Bindary, Sh. M. Morgan,
Spectrochim. Acta A 2014, 127, 310.
[14] A. Z. El‐Sonbati, M. A. Diab, A. A. El‐Bindary, A. M. Eldesoky,
Sh. M. Morgan, Spectrochim. Acta A 2015, 135, 774.
[15] A. A. El‐Bindary, G. G. Mohamed, A. Z. El‐Sonbati, M. A. Diab,
W. M. I. Hassan, Sh. M. Morgan, A. K. Elkholy, J. Mol. Liq.
2016, 218, 138.
[16] A. M. Eldesoky, M. A. El‐Bindary, A. Z. El‐Sonbati, Sh. M.
Morgan, J. Mater. Environ. Sci. 2015, 6, 2260.
[17] Sh. M. Morgan, A. Z. El‐Sonbati, M. A. El‐Mogazy, Appl.
Organometal. Chem. 2018, https://doi.org/10.1002/aoc.4264.
[18] A. Z. El‐Sonbati, M. A. Diab, Sh. M. Morgan, M. Z. Balboula,
Appl. Organometal. Chem. 2018, https://doi.org/10.1002/aoc.4059.

MORGAN ET AL.
25 of 25
[19] Sh. M. Morgan, A. Z. El‐Sonbati, H. R. Eissa, J. Mol. Liq. 2017,
240, 752.
[38] M. A. Diab, A. Z. El‐Sonbati, Sh. M. Morgan, M. A. El‐Mogazy,
Appl. Organometal. Chem. 2018, https://doi.org/10.1002/
aoc.4378.
[20] P. W. Selwood, Magnetic Chemistry, Interscience Pub. Inc., New
York 1956.
[39] K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Coordination Compounds, Wiley, New York 1986.
[21] R. Shirley, The CRYSFIRE system for Automatic Powder
Indexing‘: User's Manual, the Lattice Press, Guildford, Surrey
2000.
[40] A. B. P. Lever, Electronic spectra of ions in Inorganic Electronic
Spectroscopy, second ed., Elsevier, Amsterdam 1984.
[22] A. Z. El‐Sonbati, M. A. Diab, Sh. M. Morgan, H. A. Seyam,
J. Mol. Struc. 2018, 1154, 354.
[41] H. A. Kuska, M. T. Rogers, in Coordination Chemistry, (Ed: A.
E. Martell), Van Nostrand Reinhold, New York 1971.
[23] H. M. Refaat, H. A. El‐Badway, Sh. M. Morgan, J. Mol. Liq.
2016, 220, 802.
[42] M. C. R. Symons, D. X. West, G. Wilkinson, J. Chem. Soc.,
Dalton Trans. 1975, 1696.
[24] G. G. Mohamed, A. A. El‐Sherif, M. A. Saad, S. E. A. El‐Sawy,
Sh. M. Morgan, J. Mol. Liq. 2016, 223, 1311.
[43] A. W. Coats, J. P. Redfern, Nature 1964, 201, 68.
[44] H. H. Horowitz, G. Metzger, Anal. Chem. 1963, 35, 1464.
[25] J. Laugier, B. Bochu, LMGP‐suite suite of programs for the
interpretation of X‐ray experiments, ENSP/Laboratoire des
Materiaux et du genie physique, Saint Martin d'Heres, 2000,
pp. BP46.38042.
[45] A. Z. El‐Sonbati, M. A. Diab, Sh. M. Morgan, A. M. Eldesoky,
M. Z. Balboula, Appl. Organometal. Chem. 2018, https://doi.
org/10.1002/aoc.4207.
[46] D. S. Raja, N. S. P. Bhuvanesh, K. Natarajan, Inorg. Chim. Acta
2012, 385, 81.
[26] J. Geary, Coord. Chem. Rev. 1971, 7, 81.
[27] N. A. El‐Ghamaz, A. Z. El‐Sonbati, Sh. M. Morgan, J. Mol. Struc.
2012, 1027, 92.
[47] N. S. Habib, S. M. Rida, E. A. M. Badawey, H. T. Y. Fahmy, H.
A. Ghozlan, Eur. J. Med. Chem. 1997, 32, 759.
[28] R. M. Christie, P. N. Standring, Dyes Pigm. 1989, 11, 109.
[29] F. Karcõ, Dyes Pigm. 2008, 77, 451.
SUPPORTING INFORMATION
[30] R. M. Christie, W. T. Dryburgh, P. N. Standring, Dyes Pigm.
1991, 16, 231.
Additional Supporting Information may be found online
in the supporting information tab for this article.
[31] N. Ertan, Dyes Pigm. 1999, 44, 41.
[32] F. Karcı, N. Ertan, Dyes Pigm. 2002, 55, 99.
[33] Q. Peng, M. Li, K. Gao, L. Cheng, Dyes Pigm. 1990, 14, 89.
How to cite this article: Morgan ShM, Diab MA,
El‐Sonbati AZ. Synthesis, spectroscopic, thermal
properties, Calf thymus DNA binding and quantum
chemical studies of M(II) complexes. Appl
Organometal Chem. 2018;e4281. https://doi.org/
10.1002/aoc.4281
[34] Sh.M. Morgan, N.A. El‐Ghamaz, M.A. Diab, J. Mol. Struct. 2018,
1160, 227.
[35] P. B. Sreeja, M. R. Kurup, Spectrochim. Acta A 2005, 61, 331.
[36] Sh.M. Morgan, M. A. Diab, A. Z. El‐Sonbati, Appl. Organometal.
Chem. 2018. https://doi.org/10.1002/aoc.4305
[37] G. M. Morris, D. S. Goodsell, J. Comput. Chem. 1998, 19, 1639.