Polymer complexes. LXX. Synthesis, spectroscopic studies, thermal properties and antimicrobial activity of metal(II) polymer complexes

Article abstract of DOI:10.1002/aoc.4264

The monomer 3-allyl-5-(phenylazo)-2-thioxothiazolidine-4-one (HL) was prepared by the reaction of allyl rhodanine with aniline through diazo-coupling reaction. Reaction of HL with Ni(II) or Co(II) salts gave polymer complexes (1–8) with general stoichiome

Full text of DOI:10.1002/aoc.4264

Received: 16 November 2017
DOI: 10.1002/aoc.4264
Revised: 12 December 2017
Accepted: 13 December 2017
F U L L P A P E R
Polymer complexes. LXX. Synthesis, spectroscopic studies,
thermal properties and antimicrobial activity of metal(II)
polymer complexes
Sh. M. Morgan1
| A. Z. El‐Sonbati2
| M. A. El‐Mogazy2
1 Environmental Monitoring Laboratory,
Ministry of Health, Port Said, Egypt
2 Chemistry Department, Faculty of
Science, Damietta University, Damietta,
Egypt
The monomer 3‐allyl‐5‐(phenylazo)‐2‐thioxothiazolidine‐4‐one (HL) was pre-
pared by the reaction of allyl rhodanine with aniline through diazo‐coupling
reaction. Reaction of HL with Ni(II) or Co(II) salts gave polymer complexes
(1–8) with general stoichiometries [M(HL)(Cl)2(OH2)2]n, [M(HL)(O2SO2)
(OH2)2]n, [M(L)(O2NO)(H2O)2]n and [M(L)(O2CCH3)(H2O)2]n (where M =
Ni(II) or Co(II)). The structures of the polymer complexes were identified using
elemental analysis, infrared and electronic spectra, molar conductance, mag-
netic susceptibility, X‐ray diffraction and thermogravimetric analysis. The
interaction between the polymer complexes and calf thymus DNA showed a
hypochromism effect. HL and its polymer complexes were tested against bacte-
rial and fungal species. Co(II) polymer complex 2 is the most effective against
Klebsiella pneumoniae and is more active than penicillin. The results showed
that Ni(II) polymer complex 5 is a good antibacterial agent against Staphylococ-
cus aureus and Pseudomonas aeruginosa. Molecular docking was used to predict
the binding between the monomer with the receptors of prostate cancer (PDB
code: 2Q7L Hormone) and breast cancer (PDB code: 1JNX Gene regulation).
Coats–Redfern and Horowitz–Metzger methods were applied for calculating
the thermodynamic parameters of HL and its polymer complexes. The thermal
activation energy of decomposition for HL is higher than that for the polymer
complexes.
Correspondence
A. Z. El‐Sonbati, Chemistry Department,
Faculty of Science, Damietta University,
Damietta, Egypt.
Email: elsonbatisch@yahoo.com
KEYWORDS
antimicrobial activity, calf thymus DNA, polymer complexes, thermal analysis, thermodynamic
parameters
1 | INTRODUCTION
Transition metal polymer complexes are of particular
interest due to their various applications.[3–6] Heterocyclic
Interest in coordination chemistry is increasing continu-
ously with the preparation of organic ligands containing
an allyl group and such interest is much multiplied when
the ligands have biological importance.[1,2] The biochem-
istry and coordination chemistry of allyl heterocyclic com-
pounds have attracted increased interest due to their
chelating ability and their pharmacological applications.
azo dyes attract considerable interest and play an impor-
tant role in the development of chemistry. A literature
survey shows subtle work to synthesize and characterize
azo dyes, and also their metal complexes which are widely
used in various fields such as biological studies.[7–12]
Over the past few years, the study of rhodanine
compounds has been an active area because of their
Appl Organometal Chem. 2018;e4264.
wileyonlinelibrary.com/journal/aoc
Copyright © 2018 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.4264

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MORGAN ET AL.
importance in applied academic researches and their
diverse applications such as metal extracting agents,[13]
analytical reagents,[14] pharmacological compounds,[15]
solar cells[16] and biosensors.[17] Derivatives after substitut-
ing various groups in rhodanine also have excellent chemi-
luminescence and fluorescence performance.[18,19]
addition, the thermodynamic parameters were calculated
using the Coats–Redfern and Horowitz–Metzger methods.
2 | EXPERIMENTAL
2.1 | Materials and Reagents
The chemistry of nickel has received considerable
attention due to the discovery that nickel is an essential
metal in antibacterial and antifungal activities.[20] Nickel
complexes play an important role in biological systems
and there are a number of nickel enzymes.[20,21] In addi-
tion, nickel complexes are attracting nowadays increasing
interest in the research field of bioinorganic chemistry
andtherearemanyreportsregardingNi(II)complexeswith
antimicrobial, antibacterial, antifungal and antiprolifera-
tive properties.[22–24] Also, Co(II) complexes have attracted
attention for the thermal stability, coordination chemistry
and biological activity of some complexes for which struc-
tural information was obtained using spectrochemical
and magnetochemical techniques; due to Co(II) showing
d7 arrangement, it can have four‐coordinate tetrahedral
and six‐coordinate octahedral stereochemistry.[25–28]
Allyl rhodanine azo compounds are a subject of
growing interest and may have numerous applications,
and azo rhodanine compounds containing oxygen, sulfur
and nitrogen donor atoms are of great interest because
of their great versatility as ligands.[1,2] Because of the pres-
ence of several potential donor atoms, they have ability
and flexibility to coordinate in either deprotonated or
neutral form.
3‐Allyl‐2‐thioxothiazolidin‐4‐one and aniline were bought
from Aldrich. 2,2′‐Azobisisobutyronitrile (AIBN) was
purified by dissolving in hot ethanol and filtering.
NiSO4⋅6H2O, CoSO4⋅7H2O, MCl2⋅6H2O (M = Ni(II) and
Co(II)), M(NO3)2⋅6H2O (M = Ni(II) and Co(II)) and
M(CH3COO)2⋅ 4H2O (M = Ni(II) and Co(II)) were obtained
from Sigma Aldrich. Organic solvents (diethyl ether,
dimethylformamide (DMF), dimethylsulfoxide (DMSO)
and ethanol) were bought from BDH. Calf thymus DNA
(CT‐DNA) was acquired from SRL (India).
2.2 | Preparation of HL Monomer
Monomer (HL) was synthesized by the well‐established
standard method (Scheme 1).[4,20,29] The resulting solid
HL was recrystallized from ethanol and then dried in a
vacuum desiccator over anhydrous calcium chloride.
Analysis: found for HL monomer (C12H11N3OS2) (%): C,
52.11; H, 4.09; N, 15.31; S, 23.51; calculated (%): C,
51.99; H, 3.97; N, 15.16; S, 23.11.
2.3 | Preparation of Poly[3‐allyl‐5‐
(phenylazo)‐2‐thioxothiazolidine‐4‐one]
(PHL) Homopolymer
The present paper describes the chelation behavior of
3‐allyl‐5‐(phenylazo)‐2‐thioxothiazolidine‐4‐one
(HL)
monomer towards some ions of Ni(II) and Co(II). Molec-
ular docking was used to predict the binding between the
monomer with the receptors of prostate cancer (PDB
code: 2Q7L Hormone) and breast cancer (PDB code:
1JNX Gene regulation). The structures of the studied
Ni(II) and Co(II) polymer complexes were elucidated
using elemental analyses, infrared (IR) and UV–visible
spectra, magnetic moment, molar conductance, X‐ray dif-
fraction and thermal analysis. The antimicrobial activities
of HL and its Ni(II) and Co(II) polymer complexes are
discussed. Calf thymus DNA binding of HL and its poly-
mer complexes was studied using absorption spectra. In
PHL homopolymer was prepared by free radical initiation
of HL monomer (0.5 mol) using 0.1% (w/v) AIBN as initi-
ator and DMF (50 ml) as solvent for 6 h. The polymer
product was precipitated by pouring in distilled water
and dried in a vacuum oven for several days at 40 °C.
The PHL homopolymer was characterized using 1H
NMR analysis.
2.4 | Preparation of Polymer Complexes
Polymer complexes were prepared by refluxing Ni(II) and
Co(II) salts (0.001 mol) with HL (0.001 mol) in 20 ml of
SCHEME 1 Synthesis of monomer (HL)

MORGAN ET AL.
3 of 18
DMF as a solvent and 0.1% (w/v) AIBN as initiator, and
the resulting mixture was heated at reflux for ca 8 h.
The hot solution was precipitated by pouring in large
excess of distilled water containing dilute hydrochloric
acid, to remove the metal salts that were incorporated into
the polymer complexes. The polymer complexes (1–8;
Table 1) were filtered, washed with water and dried in a
vacuum oven at 40 °C for several days.
allow the diffusion of the compound into the agar
medium. The plates were then incubated at 37 °C for bac-
teria and 30 °C for fungi. The diameters of inhibition
zones were measured after 24 h and 7 days for bacteria
and fungi, respectively, taking into consideration the con-
trol values (DMF). Miconazole was used as antifungal
standard drug and penicillin as antibacterial standard
drug.[20,28]
2.5 | DNA Binding
2.7 | Analytical Measurements
The binding of the monomer and polymer complexes to
CT‐DNA was studied using absorption spectra.[20]
Electronic absorption spectra were obtained using a
1 cm quartz cuvette at room temperature by fixing the
concentration of compound (1 × 10−3 M), while progres-
sively increasing the concentration of CT‐DNA. The
intrinsic binding constant (Kb) of the monomer and poly-
mer complexes with CT‐DNA was determined.[20,28]
Elemental microanalyses of the compounds for C, H, S
and N were conducted with an automatic analyser (CHNS
Vario ELIII, Germany). The 1H NMR spectra were
obtained with a JEOL FX90 Fourier transform spectrome-
ter with DMSO‐d6 as the solvent and using
tetramethylsilane (TMS) as an internal standard. Mass
spectra were recorded using the EI technique at 70 eV
with a Hewlett‐Packard MS‐5988 GS‐MS. IR spectra were
recorded as KBr discs using a PerkinElmer 1340 spectro-
photometer. UV–visible spectra of the compounds were
recorded in nujol mulls using a Unicom SP 8800 spectro-
photometer. The molar conductance was measured with a
Sargent Welch Scientific Co. (Skokie, IL, USA) instru-
ment. The magnetic moments of the prepared solid com-
plexes wre determined at room temperature using the
Gouy method. Mercury(II) (tetrathiocyanato)cobalt(II),
[Hg{Co(SCN)4}], was used for the calibration of the Gouy
tubes. Magnetic moments were calculated using the equa-
2.6 | Biological Activity
For this investigation, the agar well diffusion method was
applied.[12,28] The antibacterial activity was tested on
nutrient agar medium against three local Gram‐positive
bacterial species (Enterococcus faecalis, Bacillus cereus
and Staphylococcus aureus) and three local Gram‐negative
bacterial species (Pseudomonas aeruginosa, Klebsiella
pneumoniae and Escherichia coli). Also, the antifungal
activity of the monomer and polymer complexes was
tested against three local fungal species on DOX agar
medium (yeast Candida albicans, Aspergillus niger and
Fusarium oxysporum). The concentrations of each solu-
tion of monomer and polymer complexes were 150, 100
and 50 μg ml in DMF. Utilizing a sterile cork borer
(10 mm in diameter), wells were made in agar plates pre-
viously seeded with the test microorganism. An amount
of 200 μl of each compound was applied in every well.
The agar plates were kept at 4 °C for at least 30 min to
tion μeff = 2.84 [TcM ]
coor 1/2. Thermogravimetric analysis
(TGA) was conducted with a Simultaneous Thermal Ana-
lyzer (STA) 6000 system, in the temperature range from
30 to 800 °C at a heating rate of 10 °C min−1 under
dynamic nitrogen atmosphere. X‐ray diffraction (XRD)
analysis of compounds was conducted with an X‐ray dif-
fractometer in the range 2θ = 4–80°.[30] This analysis
was carried out using Cu Kα radiation. The applied volt-
age and the tube current were 40 kV and 30 mA, respec-
tively. The diffraction peaks in powder spectra were
TABLE 1 Elemental analyses and magnetic moment of Ni(II) and Co(II) polymer complexes 1–8
Found (calcd) (%)
μeff
Complex
(B.M.)
C
H
N
S
M
[Ni(HL)(Cl)2(H2O)2]n C12H15N3O3S2Cl2Ni (1)
3.25
32.35 (32.53)
3.25 (3.39)
9.18 (9.49)
14.31 (14.46)
13.77 (13.26)
[Co(HL)(Cl)2(H2O)2]n C12H15N3O3S2Cl2Co (2)
[Ni(HL)(O2SO2)(H2O)2]n C12H15N3O7S3Ni (3)
[Co(HL)(O2SO2)(H2O)2]n C12H15N3O7S3Co (4)
[Ni(L)(O2NO)(H2O)2]n C12H14N4O6S2Ni (5)
[Co(L)(O2NO)(H2O)2]n C12H14N4O6S2Co (6)
[Ni(L)(O2CCH3)(H2O)2]n C14H17N3O5S2Ni (7)
[Co(L)(O2CCH3)(H2O)2]n C14H17N3O5S2Co (8)
4.46
3.46
4.92
3.22
4.72
3.29
4.40
32.39 (32.51)
30.66 (30.79)
30.64 (30.77)
33.22 (33.28)
33.17 (33.26)
39.04 (39.10)
39.04 (39.08)
3.27 (3.39)
3.08 (3.21)
3.15 (3.21)
3.13 (3.24)
3.14 (3.23)
3.86 (3.96)
3.84 (3.95)
9.24 (9.48)
8.68 (8.98)
8.74 (8.98)
12.69 (12.94)
12.77 (12.94)
9.54 (9.77)
9.45 (9.77)
14.19 (14.45)
20.25 (20.53)
20.39 (20.52)
14.58 (14.79)
14.55 (14.78)
14.57 (14.89)
14.64 (14.89)
13.22 (13.31)
12.79 (12.55)
12.64 (12.59)
13.77 (13.56)
13.77 (13.61)
14.04 (13.66)
13.83 (13.71)

4 of 18
MORGAN ET AL.
FIGURE 1 Structures of monomer and
its polymer complexes
indexed and the lattice parameters were determined with
the aid of the CRYSFIRE computer program.[31] The value
of interplanar spacing, d, and Miller indices, hkl, for each
diffraction peak were determined using the CHEKCELL
program.[32]
Docking calculations were carried out on receptors of
the androgen receptor prostate cancer mutant H874Y
ligand binding domain bound with testosterone and a
TIF2 box3 coactivator peptide 740‐753 (PDB code: 2Q7L
Hormone) and crystal structure of the BRCT repeat region
from the breast cancer associated protein BRCA1 (PDB
code: 1JNX Gene regulation).[3,28] Data were statistically
analysed for variance using SPSS software version 17
and the least significant difference at 0.05 level using
one‐way analysis of variance.
HL monomer. The monomer can exist in two tautomeric
forms, azo enol form (Figure 1, form B) and keto
hydrazone form (Figure 1, form C).
HL exhibits bands at ca 26 425 cm−1 (CS) (n → π*),
ca 30 640 cm−1 (CO) (n → π*) and 40 400 cm−1 (phenyl
ring) (π–π*). It has been reported that the azo deriva-
tives exhibited a strong band in the range 37 000–35
550 cm−1 whereas hydrazone showed a strong band at
ca 31 250 cm .
−1 [20]. However, HL gave a characteristic
band at ca 30 650 cm−1 for the hydrazone form
(Figure 1, form C).
Elemental analysis data for the polymer complexes are
summarized in Table 1. It is found that two types of poly-
mer complexes are formed. For the first type, the mono-
mer behaves as a neutral and contains two/one anions
(chloride/sulfate ion) (polymer complexes with equivalent
anions (1–4)):
3 | RESULTS AND DISCUSSION
3.1 | Structures of Monomer and Polymer
Complexes
NiCl2⋅6H2O
CoCl2⋅6H2O
NiSO4⋅6H2O
CoSO4⋅7H2O
+ HL
+ HL
+ HL
+ HL
→
→
→
→
[Ni(HL)(Cl)2(H2O)2]n
[Co(HL)(Cl)2(H2O)2]n
[Ni(HL)(O2SO2)(H2O)2]n
[Co(HL)(O2SO2)(H2O)2]n
HL was synthesized by the diazotization of aniline with
allyl rhodanine. The elemental analysis data obtained
were in good agreement with the stoichiometry of the

MORGAN ET AL.
5 of 18
For the second type, the monomer behaves as a mono-
basic anion (nitrate or acetate ion) (polymer complexes
complexes and bonding modes were inferred from charac-
teristic band positions in IR spectra.
with half equivalent anions (5–8)):
Elemental analysis of HL, as detailed in Section 2.2,
indicates that the monomer has the molecular formula
C12H11N3OS2. The mass spectrum of the monomer
exhibits a peak at 277 amu conforming to the formula
(C12H11N3OS2) as shown in Figure S1. It is obvious that
the molecular ion peaks are in good agreement with the
suggested empirical formulae as determined from ele-
mental analyses (Table 1). The ion at m/z = 277
fragmented to a stable peak at m/z = 261 by loss of oxygen
atom as shown in Scheme 2 (structure І). The peaks corre-
sponding to various fragments of HL monomer appeared
at m/z = 176 (structure ІІ), 149 (structure ІIІ), 91 (struc-
ture ІV) and 77 (structure V) by loss C4H5S, CHN, CSN
and N atoms, respectively.
Ni(NO3)2⋅6H2O
+
HL
→
[Ni(L)(O2NO)(H2O)2]n + HNO3
Co(NO3)2⋅6H2O
+
HL
→
[Co(L)(O2NO)(H2O)2]n + HNO3
HL
Ni(CH3COO)2⋅4H2O
+
→
[Ni(L)(O2CCH3)(H2O)2]n +
CH3COOH
Co(CH3COO)2⋅4H2O +
HL
→
[Co(L)(O2CCH3)(H2O)2]n +
CH3COOH
The 1H NMR spectrum of HL supports the occurrence
of the form depicted in Figure 1. The 1H NMR spectrum of
the monomer was recorded in DMSO‐d6 using TMS as the
internal standard. The broad signal at ca 11.199 ppm was
assigned to intramolecular hydrogen bonded proton of
NH (hydrazone) (Figure S2a) which disappeared in the
presence of D2O (Figure S2b). These results are in agree-
ment with those obtained by Diab et al.[2] where proton
of NH (hydrazone) showed a signal at ca 11.4 ppm. The
protons of the aromatic ring resonate downfield in the
range 7.045–7.393 ppm.
The general formulae for the polymer complexes is
[M(HL)(Cl2 or O2SO2)(OH2)2]n and [M(L)(O2NO or
O2CCH3)(OH2)2]n (where M = Ni(II) or Co(II)). The high
decomposition temperature of all polymer complexes as
well as their insolubility in common organic solvents,
but soluble in DMF and DMSO, suggest the polymeric
nature of all polymer complexes.
The elemental analysis results show 1:1 (metal:mono-
mer) stoichiometry for all the polymer complexes and the
results are in good agreement with the general formulae
(Table 1). The molar conductivities (Λm) of 10−3 M solu-
tions of the Ni(II) and Co(II) polymer complexes in
DMSO at 25 °C were measured, and were found to be
non‐electrolytic in nature with values in the range 3.4–
7.8 Ω−1 cm2 mol−1. The formation of HL and its polymer
1
The H NMR spectrum of HL showed the expected
peaks and pattern of the vinyl group (CH2═CH), i.e.
5.885 ppm for the vinyl CH proton and 5.138 ppm (cis)
and 5.180 ppm (trans) for the vinyl CH2 protons; these
peaks disappeared on polymerization. This indicates that
SCHEME 2 Fragmentation patterns of monomer

6 of 18
MORGAN ET AL.
the polymerization of HL occurs at the vinyl group.[2] It is
worth noting that the rest of the proton spectra of HL and
PHL remain almost without change.
(2Q7L and 1JNX) are shown in Figures S6–S8, showing
bending interaction sites of HL (forms A–C) with protein
active sites of receptors. Figures S6–S8 reveal that 2Q7L
and 1JNX receptors cannot form hydrogen bonds with
hetero atoms of HL (form B), while 2Q7L and 1JNX recep-
tors can form bonds depending on active site of protein
receptors and HL (forms A and C) as shown in Table 3.
The XRD patterns of HL and its polymer complexes
(1–8) are presented in Figure 5. The XRD patterns of HL
and polymer complexes 1, 3–6 show many diffraction
peaks which indicate polycrystalline phases. XRD
patterns of polymer complexes 2, 7 and 8 show in the
range 2θ = 20–30° a broad peak indicating completely
amorphous structures for these polymer complexes.[20]
The average crystallite size (ξ) was calculated according
to the Debye–Scherrer equation:[3,28]
Molecular docking aims to achieve an optimized con-
formation for both protein and drug with relative orienta-
tion between them such that the free energy of the overall
system is minimized.[33,34] In this context, we used molec-
ular docking between HL (forms A–C) and the receptors of
prostate cancer and breast cancer. The data showed a
favourable arrangement between HL (forms A–C) and
the receptors of prostate cancer and breast cancer. The
interaction curves are shown in Figures 2–4 and the calcu-
lated energy and some parameters associated with the
selected anticancer receptors are listed in Table 2. In gen-
eral a more negative charge represents a more stable inter-
action, where the estimated free energy of binding, the
estimated inhibition constant (Ki) and the interaction
surface area reveal the most favoured binding.[28] So, the
obtained data show a more favourable interaction between
HL (forms A–C) and the receptor of 2Q7L (prostate
cancer) than the receptor of 1JNX (breast cancer)
(Table 2). The HB plot curves explain the interactions
between HL (forms A–C) and receptors (2Q7L and 1JNX)
as shown in Figures S3–S5. The two‐dimensional plot
curves of binding for HL (forms A–C) with the receptors
0:95λ
1=2 cosθ
ξ ¼
(1)
β
where β1/2 is the width at half maximum of the refer-
ence diffraction peak measured in radians and λ is the
wavelength of X‐ray radiation (1.540598 Å). The equation
uses the reference peak width at angle θ. The dislocation
density (δ) is the number of dislocation lines per unit
FIGURE 2 Monomer (form A) (green
in (a) and grey in (b)) in interaction with
receptors of 2Q7L and 1JNX

MORGAN ET AL.
7 of 18
FIGURE 3 Monomer (form B) (green in
(a) and grey in (b)) in interaction with
receptors of 2Q7L and 1JNX
FIGURE 4 Monomer (form C) (green in
(a) and grey in (b)) in interaction with
receptors of 2Q7L and 1JNX

8 of 18
MORGAN ET AL.
TABLE 2 Energy values obtained in docking calculations of HL (forms A–C) with receptors of prostate cancer (PDB code: 2Q7L Hormone)
and breast cancer (PDB code: 1JNX Gene regulation)
Estimated free energy of binding
(kcal mol−1
Total intercooled energy
(kcal mol−1
Interaction
surface
Compounda
Receptor
)
)
HL (form A)
2Q7L
1JNX
−7.20
−3.48
−8.30
−6.26
517.65
550.325
HL (form B)
HL (form C)
2Q7L
1JNX
−7.22
−4.45
−8.85
−5.94
508.452
518.626
2Q7L
1JNX
−7.25
−4.54
−8.73
−5.82
495.055
556.472
aStructures are shown in Figure 1.
TABLE 3 HL (forms A and C) binding to protein with hydrogen bond interactions with receptors (2Q7L and 1JNX)
Compounda
Receptor
Chemical structure
Hydrogen bondb
HL (form A)
2Q7L
N* (3.43 Å)–LEU704 (O)
1JNX
N** (2.97 Å)–ARG1699 (O)
HL (form C)
2Q7L
1JNX
N* (3.29 Å)–MET742 (SD)
N* (2.62 Å)–ASN1774 (O)
aStructures are shown in Figure 1.
bBonds as given in Figures S3–S8.
area of the crystal and calculated by the following
equation:[3]
phenomena and this has been confirmed by a number
of previous published data of analogous keto hydrazone.
It seems that HL has different types of hydrogen bond-
ing:[2] (i) intramolecular hydrogen bonding (Figure 1,
forms B and C) and (ii) intermolecular hydrogen bonding.
Case (i) is more favoured than case (ii). Also, a broad
band for enolic (OH) group does not appear in the IR
spectrum of monomer and the broad band located at
3114–3430 cm−1 leads one to characterize νNH rather
than hydrogen bonded ─OH with N=N, 3067 cm−1
(=C─H str.), 2958–3028 cm−1 (C─H str. ─CH2) and
2916 cm−1 (C─H str. sym.). This is confirmed from the
observation of Karabatsos et al.[35] where the hydrazone
form is more favoured than the azo structure for similar
compounds. The low frequency and the broadness of this
band suggest that the monomer has strong hydrogen
bonding (N─H···O) in the solid state.[36,37] The other
characteristic peaks at ca 1383 and 1074 cm−1 are due
to ν(C─N) and ν(N─N) modes, respectively. Therefore,
on the basis of IR data, we concluded that there is a shift
of equilibrium to azo allyl rhodanine configuration and
1
ξ2
δ ¼
(2)
Values of ξ are 33, 31, 47, 65, 37 and 32 nm and values
of δ are 9.18 × 10−4, 1.04 × 10−3, 4.53 × 10−4, 2.37 × 10−4
,
7.30 × 10−4 and 9.77 × 10−4 nm−2 for HL and polymer
complexes 1, 3–6, respectively.
The estimated lattice parameters (a, b, c, α, β and γ),
Miller indices (hkl) and interplanar spacing (d) for HL
and polymer complexes 1, 3–6 were determined using
the CHEKCELL program[31] and the data are summarized
in Tables S1–S6.
The IR spectrum of the prepared HL shows a strong
carbonyl absorption band appearing at ca 1722 cm−1
(Figure S9) consistent with keto hydrazone form with
extensive six‐membered intramolecular hydrogen bond-
ing, since the peak appearing at ca 1640 cm−1 is attrib-
uted to ν(C═N) structure through resonance

MORGAN ET AL.
9 of 18
the monomer exists in keto hydrazone form (Figure 1,
form C) in the solid state.
The mode of bonding of HL to the metal ions was
elucidated by comparing the IR spectra of the polymer
complexes with literature data for related systems.
3. The observed new IR band assigned to ν(NH)
(hydrazone) for the free HL is absent for the polymer
complexes, suggesting the cleavage of intramolecular
hydrogen bonded ν(NH)[38] with subsequent depro-
tonation of NH group and coordination of nitrogen
to the metal ions as shown in polymer complexes 5–8.
4. Coordination of the carbonyl oxygen and hydrazone
nitrogen (NH/N) in the chelate ring is supported by
the appearance of new IR bands at 550–576 and
430–446 cm−1 which are assigned to M─O and
M─N, respectively. The phenyl ring vibration appears
1. In all complexes the IR bands at ca 3114–3490 cm−1
are attributed to different probabilities: (a) due to
either free NH; (b) due to bonded ─NH group; or
(c) due to the presence of coordinated water
molecules.
2. The strong band in the IR spectrum of HL is safely
assigned to ν(N─NH) vibration mode.[2] Upon com-
plex formation with metal ions, this band is shifted
to longer wavenumber as a weak band. This shows
that the hydrazone group is involved in coordination
in polymer complexes 1–4.[10]
at 1428–1550 cm−1
.
5. The bands characteristic of coordinated water mole-
cules are observed at ca 897 cm−1, including rocking,
wagging and the metal–oxygen stretching vibrations
at 958, 747 and 692 cm−1, respectively. The other bend-
ing vibration of the water molecules δ(OH2), usually
FIGURE 5 X‐ray diffraction patterns of HL and polymer complexes

10 of 18
MORGAN ET AL.
FIGURE 5 Continued.
present at ca 1600 cm−1, is overlapped with the skele-
ton vibration of the benzene ring (C═C vibration).
6. The chloride test confirmed coordination for both
chloride counter ions. Polymer complexes 1 and 2
react with AgNO3 in HNO3 solution. This fact is taken
as evidence that chloride ions are bonded to the metal
in the complex. Absorption bands at ca 1155–1120 cm
−1 (ν3), 925 cm−1 (ν1), 660 cm−1 (ν4) and 550 cm−1 (ν2)
for the sulfato polymer complexes 3 and 4 are consis-
tent with those normally associated with bidentate
chelating sulfato group.[39] In the IR spectra of the
nitrato polymer complexes 5 and 6, a value of ca
18 cm−1 for the difference between ν5 and ν1 indicates
a bidentate mode of coordination.[40] The IR spectra of
polymer complexes 7 and 8 derived from Ni(II) and
Co(II) acetate show absorption bands at ca 1439 and
1445 cm−1 which are assigned to ν(C─O) antisymmet-
ric stretching of acetate group and others at ca 1486
and 1493 cm−1 which can be assigned to ν(C─O) sym-
metric stretching vibration of acetate. A difference Δν
= 48–50 cm−1 indicates the mononegative bidentate
coordination of the acetate group.[20,41]
of the results for these polychelates reveals that they fall
in the expected range in agreement with spectral findings.
The Ni(II) polymer complexes reported herein were of
high spin with room temperature magnetic moment
values of μeff = 3.22–3.46 B.M. which are in the normal
range observed for octahedral Ni(II) polymer complexes.
This indicates that the polymer complexes of Ni(II) are
six‐coordinate and probably octahedral.[20,42] The elec-
tronic spectra of Ni(II) polymer complexes exhibit three
d–d bands at ca 8400–9525 cm−1 (ν1) (3A2g(F) →
3
2T2g(F)), 13 420–15 870 cm−1 (ν2) (3A2g(F) → T1g(F))
3
and 23 800–24 400 cm−1 (ν3) (3A2g(F) → T1g(P)), which
are in the normal ranges observed for octahedral Ni(II)
polymer complexes.[42] Transition energy ratio (ν2/ν1)
obtained for all Ni(II) polymer complexes is in the range
1.64–1.70. This is indicative of octahedral geometry. The
Dq values again confirm the octahedral configuration of
the chelates.[20] The percent covalency was found to be
greater for sulfato and less for acetato polymer complexes.
The order of the Dq values among these Ni(II) polymer
complexes was found to be Cl− < CH3COO− < NO3
−
< SO42−. Ligand field stabilization energies for the octahe-
dral Ni(II) polymer complexes were found to have the
following order: 3 > 5 > 7 > 1.
The values of magnetic moments at room temperature
for Co(II) polymer complexes lie in the range 4.40–4.92
B.M., which correspond to three unpaired electrons.
The reflectance spectra of polymer complexes exhibit
3.2 | Magnetic Moments and Electronic
Spectra
The results of magnetic moment measurements of all the
polymer complexes are presented in Table 1. Examination
4
4
three absorption bands assigned to the T1g → T2g(F)

MORGAN ET AL.
11 of 18
4
4
(ν1) (8300–11 904 cm−1), T1g → A2g (ν2) (15 479–18
180 cm−1) and T1g → T1g(P) (ν3) (17 543–26 660 cm−1
)
4
4
transitions, which are in accord with octahedral
geometry.[22]
The calculated values of ligand field splitting energy
(10Dq), the Racah interelectronic repulsion parameter
(B) and the nephelauxetic ratio (β) support the proposed
geometry for all the Ni(II) and Co(II) octahedral polymer
complexes. Ligand field parameter Dq, B and β were cal-
culated for the polymer complexes and are listed in
Table 4. Parameter β was calculated for the polymer com-
plexes and the values lie in the range 0.71–0.93 cm−1
.
These values indicate the presence of covalent character
of the metal–ligand ‘σ’ bond. The values of the ν2/ν1 ratio
suggest an octahedral structure for the polymer com-
plexes.[43] The intense bands are characteristic of octahe-
dral field around Co(II).
The nephelauxetic ratio (β) for the Ni(II) and Co(II)
polymer complexes is less than one suggesting partial
covalency in the metal–ligand bond. The octahedral
geometry of these polymer complexes is further supported
by the value of ν2/ν1. In general, sterically bulky ligands
give rise to relatively low Dq values.[44] Here, the values
of Dq obtained for our polymer complexes are relatively
low which clearly show the considerable amount of bulk-
iness in the polymer complexes.
3.3 | Thermal Analysis
FIGURE 6 TGA curves of (a) monomer and Ni(II) polymer
The TGA curves are shown in Figure 6 and loss of mass
recorded in Table 5. The TGA curve of the monomer
shows three degradation stages. The first step in the tem-
perature range 160–281 °C is attributed to loss of
C9H6N3O (found 61.47%; calcd 62.09%) and the second
step in temperature range 281–754 °C is attributed to loss
of C2H5S2 (found 33.12%; calcd 33.58%). The third step
represented the loss of one carbon atom at >754°C (mass
loss: found 5.51%; calcd 4.33%).
complexes and (b) Co(II) polymer complexes
the temperature range 107–252 °C is attributed to loss of
two coordinated H2O molecules and C8H7NSCl2 (found
57.12%; calcd 57.83%).[20] The second stage at 252–
800 °C is related to loss of C4H4N2S (found 25.36%; calcd
25.30%) and nickel oxide remained as a residue with mass
percent of 17.52% (calcd 16.87%).
Polymer complex 2 decomposed in two steps. The first
starts at 117–340 °C and corresponded to the loss of two
coordinated H2O molecules and C7H7NSCl2 (found
The thermal decomposition of polymer complex 1
proceeded with two degradation stages. The first stage in
TABLE 4 Electronic parameters of metal(II) polymer complexes
Complex
1
B (cm−1
)
Dq (cm−1
)
β
LFSE (kcal mol−1
)
Environment
856
813
0.83
27.94
N, 3O, 2Cl
2
3
4
5
6
7
8
798
779
845
799
1037
878
1018
884
952
1150
870
996
840
1052
0.71
0.75
0.75
0.77
0.93
0.85
0.91
25.32
32.72
32.94
29.90
34.23
28.87
30.13
N, 3O, 2Cl
N, 5O
N, 5O
N, 5O
N, 5O
N, 5O
N, 5O

12 of 18
MORGAN ET AL.
TABLE 5 TGA data for HL and polymer complexes
Weight loss (%)
Temperature
range (°C)
Compound
Found
Calc.
Assignment
HL
160–281
281–754
>754
61.47
33.12
5.51
62.09
33.58
4.33
C9H6N3O
C2H5S2
C
1
2
3
4
107–252
252–800
>800
57.12
25.36
17.52
57.83
25.30
16.87
Coordinated 2H2O molecules + C8H7NSCl2
C4H4N2S
NiO
117–340
340–542
>542
55.23
27.96
16.81
55.09
27.99
16.92
Coordinated 2H2O molecules + C7H7NSCl2
C5H4N2S
CoO
70–262
262–560
>560
56.66
24.57
18.77
56.02
25.44
18.54
Coordinated 2H2O molecules + C8H6N2SO4
C3H5NS2
NiO + 1C
40–269
269–372
372–487
>487
59.65
13.53
10.75
16.07
60.27
14.96
8.76
Coordinated 2H2O molecules + C7H6N2S2O4
C2NS
C3H5
CoO
16.01
5
6
125–248
248–507
>507
54.94
27.54
17.52
54.08
28.66
17.26
Coordinated 2H2O molecules + C7H6N2O3S
C5H4N2S
NiO
137–251
251–395
395–480
>480
51.93
20.23
10.33
17.51
51.05
22.17
9.47
Coordinated 2H2O molecules + C6H5N2O3S
C3N2S
C3H5
CoO
17.31
7
8
90–235
235–367
367–700
>700
22.21
17.94
41.86
17.99
22.11
17.92
42.59
17.38
Coordinated 2H2O molecules + C2H3O2
C6H5
C6H5N3S2
NiO
60–412
412–610
610–800
>800
44.61
25.90
11.91
17.58
42.80
26.98
12.79
17.43
Coordinated 2H2O molecules + C9H8O2
C2N2S2
C3H5N
CoO
55.23%; calcd 55.09%). The second step represented the
loss of C5H4N2S at 340–542 °C (found 27.96%; calcd
27.99%) and leaving CoO as a residue with mass percent
of 16.81% (calcd 16.92%).
The TGA curve of polymer complex 3 showed two
steps. The first stage at 70–262 °C with weight loss of
56.66% (calcd 56.02%) was consistent with the loss of
two coordinated H2O molecules and C8H6N2SO4. The sec-
ond stage at 262–560 °C was related to loss of C3H5NS2
(found 25.36%; calcd 25.30%) and NiO remained as a res-
idue contaminated with one carbon atom with mass per-
cent of 18.77% (calcd 18.54%).
The thermal decomposition of polymer complex 4
proceeded with three degradation steps within the range
40 to 487 °C. The first started at 40–269 °C and
corresponded to the loss of two coordinated H2O mole-
cules and C7H6N2S2O4 (found 59.65%; calcd 60.27%).
The second and third steps represented the loss of
remaining monomer molecules (C2NS and C3H5) at 269–
487 °C (found 24.28%; calcd 23.72%), with CoO as a resi-
due with mass percent of 16.07% (calcd 16.01%).
The TGA curve of polymer complex 5 showed two
stages of decomposition. The first stage at 125–248 °C
corresponded to the loss of two coordinated H2O mole-
cules and C7H6N2O3S with a weight loss of 54.94% (calcd
54.08%) and the second stage at 248–507 °C was related to
loss of C5H4N2S (found 27.54%; calcd 28.66%). Nickel
oxide remained as a residue with mass percent of 17.52%
(calcd 17.26%).
The thermal decomposition of polymer complex 6
proceeded with three degradation stages. The first stage in
the range 137–251 °C was attributed to loss of two coordi-
nated H2O molecules and C6H5N2O3S (found 51.93%; calcd
51.05%),[20] the second stage at 251–395 °C was related to
loss of C3N2S (found 20.23%; calcd 22.17%) and the third
stage at 395–480 °C correlated with elimination of C3H5

MORGAN ET AL.
13 of 18
(found 10.33%; calcd 9.47%), with cobalt oxide as a residue
with mass percent of 17.51% (calcd 17.31%).
The thermogram of polymer complex 8 showed three
decomposition steps within the range 60–800 °C. The
first decomposition step within the range 60–412 °C
corresponded to the loss of two coordinated H2O mole-
cules and C9H8O2 with a mass loss of 44.61% (calcd
42.80%) and the second decomposition step at 412–
610 °C was related to loss of C2N2S2 (found 25.90%; calcd
26.98%). The third step (610–800 °C) corresponded to the
removal of remaining part of the monomer (C3H5N)
with a mass loss of 11.91% (calcd 12.79%), and leaving
CoO as a residue with mass percent of 17.58% (calcd
17.43%).
Polymer complex 7 showed three decomposition steps
within the range 90–800 °C. The first decomposition step
within the temperature range 90–235 °C corresponded to
the loss of two coordinated H2O molecules and C2H3O2
(found 22.21%; calcd 22.11%)[20] and the second decompo-
sition step at 235–367 °C was related to loss C6H5 (found
17.94%; calcd 17.92%). The third step (367–700 °C)
corresponded to C6H5N3S2 with a mass loss of 41.86%
(calcd 42.59%), and leaving NiO as a residue with mass
percent of 17.99% (calcd 17.38%).
TABLE 6 Thermodynamic data for thermal decomposition of HL and polymer complexes
Decomposition
temperature
Compound (°C)
Thermodynamic parameters
Correlation
coefficient
Methoda Ea (kJ mol−1
)
ΔS* (J mol−1 K−1
)
ΔH* (kJ mol−1
)
ΔG* (kJ mol−1
)
HL
160–281
CR
HM
CR
107
116
41.9
52.8
−86.9
−52.5
−233
−218
103
112
36.6
47.5
146
138
186
187
0.99484
0.99916
0.98993
0.99613
281–450
HM
1
147–252
252–477
CR
HM
CR
37.8
39.9
78.6
85.5
−191
−211
−199
−162
33.9
35.9
73.3
80.2
124
136
200
184
0.99433
0.98758
0.99716
0.99402
HM
2
117–340
464–542
CR
HM
CR
34.1
38.2
91.6
94.6
−200
−221
−201
−179
30.0
34.0
85.1
88.1
130
145
241
227
0.99749
0.99593
0.99605
0.99799
HM
3
140–262
262–481
CR
HM
CR
86.9
95.4
99.8
102
−115
−87.1
−188
−136
83.0
91.5
94.4
97.1
137
133
216
185
0.9995
0.99545
0.99401
0.99393
HM
4
148–269
372–525
CR
HM
CR
83.6
90.9
132
145
−109
−100
−118
−94.9
79.6
86.9
126
139
132
135
211
207
0.99441
0.99798
0.99073
0.99065
HM
5
147–400
400–509
CR
HM
CR
39.2
43.6
131
141
−234
−219
−105
−102
34.7
39.1
125
135
162
158
201
209
0.99501
0.99737
0.99679
0.99782
HM
6
137–251
395–517
CR
HM
CR
36.7
40.1
122
133
−227
−209
−142
−113
32.8
36.3
115
127
139
134
219
210
0.99695
0.96607
0.99088
0.99385
HM
7
140–387
387–552
CR
HM
CR
35.7
44.3
124
134
−236
−215
−143
−116
31.2
39.9
118
128
158
155
224
214
0.99494
0.99199
0.99667
0.99593
HM
8
100–412
665–797
CR
HM
CR
28.9
38.5
95.7
106
−255
−226
−206
−200
24.5
34.1
87.3
97.9
159
154
294
299
0.99777
0.99633
0.99912
0.99785
HM
aCR, Coats–Redfern; HM, Horowitz–Metzger.

14 of 18
MORGAN ET AL.
2. The Ea value of polymer complex 1 is higher than
those of the other complexes.
3.4 | Kinetic Studies
The thermodynamic parameters for HL and its polymer
complexes, namely enthalpy (ΔH*), thermal activation
energy of decomposition (Ea), Gibbs free energy change
of decomposition (ΔG*) and entropy (ΔS*), are calculated
using the Coats–Redfern and Horowitz–Metzger
methods.[45,46] ΔH* and ΔG* were calculated using
ΔH* = Ea − RT and ΔG* = ΔH* − TΔS*, respectively.
The thermodynamic data obtained with the Coats–
Redfern and Horowitz–Metzger methods for HL and poly-
mer complexes 1–8 are shown in Figures S10 and S11 and
the thermodynamics parameters are summarized in
Table 6. The data obtained from the two methods are
comparable and can be considered in good agreement
with each other.[28] The data obtained are summarized
in the following:
3. ΔG* values for HL and its polymer complexes are pos-
itive and confirmed the process is non‐spontaneous.
4. ΔS* values of HL and its polymer complexes are neg-
ative indicating the reaction is slow or the activated
complex is more ordered than the reactants.[3,20]
5. The effect of the different metals on Ea is shown in
Figure 7. It was found that the values of Ea for Ni(II)
polymer complexes are greater than those for Co(II)
polymer complexes.[28]
3.5 | DNA Binding Studies
DNA is a major target for drugs, and studies of the nature
of the binding of these small molecules to DNA are impor-
tant and fundamental for life sciences.[47,48] DNA is one of
the most important biomacromolecules in life processes
because it carries inheritance information and instructs
biological synthesis.[3,49]
1. The Ea values of the polymer complexes are less than
that of HL.
TABLE 7 Intrinsic binding constants (Kb) of HL and polymer
complexes
Compound
Kb (M−1
)
HL
9.96 × 104
2.49 × 105
2.31 × 105
3.09 × 105
2.89 × 105
2.87 × 105
2.56 × 105
1.14 × 105
1.01 × 105
1
2
3
4
5
6
7
8
FIGURE
7
Histograms of thermal activation energy of
decomposition data for Ni(II) and Co(II) polymer complexes: (a)
FIGURE 8 Histogram of intrinsic binding constant (Kb) values
Coats–Redfern method; (b) Horowitz–Metzger method
for Ni(II) and Co(II) polymer complexes

MORGAN ET AL.
15 of 18
The intercalation of monomer and polymer com-
where εa is the molar extinction coefficient observed for
Aobs/[monomer or polymer complex] at a specific DNA
concentration, εf is the molar extinction coefficient of
the free monomer or polymer complex in solution,
[DNA] is the concentration of CT‐DNA in base pairs
and εb is the molar extinction coefficient of the mono-
mer or polymer complex when fully bound to DNA.
Plots of [DNA]/(εa − εf) versus [DNA] (Figure S12) were
used to determine Kb.
The Kb values were calculated and are recorded in
Table 7. The Ni(II) polymer complexes (1, 3, 5 and 7) have
the highest values of Kb (Figure 8), indicating that the
Ni(II) polymer complexes more strongly bind with CT‐
DNA which can be due to the lower ionic radius of Ni(II)
compared to Co(II).[28,50,51]
plexes with CT‐DNA was investigated using absorption
spectroscopy to determine the intrinsic binding constant
(Kb). In the presence of DNA, the absorption bands of
HL and polymer complexes 1–8 at about 425, 417, 423,
396, 399, 391, 417, 422 and 421 nm, respectively, exhib-
ited hypochromism and a red shift of about 1–3 nm
(Figure S12). It was found that the absorption bands
of HL and its polymer complexes decrease with increas-
ing concentration of CT‐DNA.[3,28] Kb of HL and its
polymer complexes is determined using the following
equation:[28]
½DNAꢀ ½DNAꢀ
1
¼
þ
(3)
εa−εf
εb−εf
Kbðεa−εf Þ
TABLE 8 Antibacterial activity of monomer and polymer complexesa
Gram‐positive bacteria
Gram‐negative bacteria
Conc.
Bacillus Staphylococcus Enterococcus Escherichia Klebsiella
Pseudomonas
Compound
(μg/ml) cereus
aureus
faecalis
coli
pneumoniae aeruginosa
HL
50
100
150
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
2.0
2.0
−ve
−ve
−ve
−ve
−ve
−ve
0
0
1
2
3
4
5
6
7
8
50
100
150
−ve
−ve
−ve
−ve
0.4
0.6
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
0
0
50
100
150
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
0.2 0b
0.2 0b
0.2 0b
−ve
−ve
−ve
50
100
150
0.4
0.6
0.8
0
0
0
−ve
0.4
0.35 0.04
−ve
−ve
−ve
0.2
0.2
0.4
0
0
0
−ve
−ve
−ve
−ve
−ve
−ve
0
50
100
150
−ve
−ve
−ve
−ve
0.2
0.4
−ve
−ve
−ve
0.3
0.3
0.3
0
0
0
−ve
−ve
−ve
−ve
−ve
−ve
0
0
50
100
150
−ve
−ve
0.4
0.4
0.77 0.06
0.88 0.02
0
−ve
−ve
−ve
0.4
0.4
0.5
0
0
0
−ve
−ve
−ve
−ve
0.33 0.033
0.33 0.033
0
50
100
150
−ve
−ve
−ve
−ve
0.2
0.2
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
0.40
0.47 0.033
0.53 0.033
0
0
0
50
100
150
0.2
0.4
0.4
0
0
0
−ve
−ve
−ve
−ve
−ve
−ve
0.4
0.6
0.6
0
0
0
−ve
−ve
−ve
−ve
−ve
−ve
50
100
150
−ve
−ve
0.2
−ve
−ve
−ve
−ve
−ve
−ve
0.2
0.2
0.6
0
0
0
−ve
−ve
−ve
−ve
−ve
−ve
0
Penicillin (standard drug) 50
100
150
1
3
3
0.14
0.28
0.14
2
2
2
0
0.14
0
1.46 0.03
1.86 0.03
1
3
3
0
0
0
−ve
−ve
−ve
0.87 0.033
1.06 0.033
1.4 0.058
2.2
0
aData recorded as average diameter of inhibition zone (mm) standard deviation.
bIndicates significantly different value from that of penicillin.

16 of 18
MORGAN ET AL.
TABLE 9 Antifungal activity of monomer and polymer complexesa
Compound
Conc. (μg/ml)
Aspergillus niger
Fusarium oxysporum
Candida albicans
HL
50
100
150
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
1
50
100
150
−ve
0.9 0.1
0.9
−ve
0.6
0.6
−ve
−ve
−ve
0
0
0
0
2
50
100
150
−ve
−ve
−ve
0.2
0.3 0.1
0.8
0
−ve
−ve
−ve
0
3
50
100
150
−ve
−ve
0.8
−ve
−ve
−ve
−ve
−ve
−ve
4
50
100
150
−ve
−ve
−ve
0.4
0.6
1
0
0
−ve
−ve
−ve
0
5
50
100
150
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
6
50
100
150
−ve
−ve
−ve
0.4
1
1
0
−ve
−ve
−ve
0
0
7
50
100
150
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
8
50
100
150
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
−ve
Miconazole (standard drug)
50
100
150
1
3
4
0
0.14
0
2
3
3
0
0
0
1.1
1.3
1.7 0.058
0
0
aData recorded as average diameter of inhibition zone (mm) standard deviation.
(Table 8). Also, Ni(II) polymer complex 5 has antibacterial
activity against B. cereus, S. aureus, E. coli and P.
aeruginosa and has no antibacterial activity against E.
faecalis and K. pneumoniae. Ni(II) polymer complex 7
has antibacterial activity against B. cereus, and E. coli
and has no antibacterial activity against S. aureus, E.
faecalis, K. pneumoniae and P. aeruginosa.
Co(II) polymer complex 2 has antibacterial activity
against K. pneumoniae and has no antibacterial activity
against B. cereus, S. aureus, E. faecalis, E. coli and P.
aeruginosa. Co(II) polymer complex 2 is more active than
penicillin against K. pneumoniae. The antibacterial activ-
ity of Co(II) polymer complex 2 may be because of there
being two chloride ions and because of the type of metal.
Polymer complex 4 has antibacterial activity against E.
coli and S. aureus and has no antibacterial activity against
B. cereus, E. faecalis, K. pneumoniae and P. aeruginosa
(Table 8). Co(II) polymer complex 6 has antibacterial
activity against S. aureus and P. aeruginosa and has no
3.6 | Antimicrobial Studies
Antifungal and antibacterial activities of the monomer
and polymer complexes were investigated. The data are
presented in Tables 8 and 9. Polymer complexes and
monomer have no antibacterial activity against E. faecalis
and K. pneumoniae except Co(II) polymer complex 2 that
has antibacterial activity against K. pneumoniae, being
more active than penicillin which was used as standard
antibacterial drug. The monomer was found to have anti-
bacterial activity against E. coli and has no antibacterial
activity against P. aeruginosa, K. pneumoniae, S. aureus,
B. cereus and E. faecalis.
Polymer complex 1 has antibacterial activity against S.
aureus and has no antibacterial activity against E. coli, K.
pneumoniae, B. cereus, E. faecalis and P. aeruginosa. Poly-
mer complex 3 has antibacterial activity against B. cereus,
S. aureus and E. coli and has no antibacterial activity
against E. faecalis, K. pneumoniae and P. aeruginosa

MORGAN ET AL.
17 of 18
antibacterial activity against B. cereus, E. faecalis, E. coli
and K. pneumoniae. Co(II) polymer complex 8 has anti-
bacterial activity against B. cereus and E. coli and has no
antibacterial activity against S. aureus, E. faecalis, K.
pneumoniae and P. aeruginosa. In addition, polymer com-
plexes 5 and 6 have moderate antibacterial activity against
P. aeruginosa when compared to penicillin.
3. The value of thermal activation energy of decomposi-
tion for monomer is higher compared to the polymer
complexes.
ACKNOWLEDGEMENT
The results of the antifungal activities of the monomer
and its polymer complexes are recorded in Table 9.
The results reveal that polymer complex 1 is moder-
ately toxic against A. niger and F. oxysporum, whereas
it has no anticandidal activity. Polymer complex 3 has
a small effect against A. niger and has no antifungal
activity against F. oxysporum and no anticandidal activ-
ity. Our results are similar to those of Habib et al.[52]
who studied the antimicrobial activities of some
rhodanine derivatives and they revealed that the most
pronounced antifungal activity was against A. niger
and Penicillium sp.
Co(II) polymer complex 2 is of low toxicity against F.
oxysporum and Co(II) polymer complexes 4 and 6 are of
high toxicity against F. oxysporum. Co(II) polymer com-
plexes 2, 4 and 6 have no antifungal activity against A. niger
and C. albicans. The monomer, Ni(II) polymer complexes 5
and 7 and Co(II) polymer complex 8 have no antifungal
activity against A. niger, F. oxysporum and C. albicans.
The authors thank Prof. Dr M.I. Abou‐Dobara, Botany
Department, Faculty of Science, Damietta University, Egypt
for his help during investigation of antimicrobial activity.
ORCID
Sh. M. Morgan http://orcid.org/0000-0002-8921-4894
A. Z. El‐Sonbati http://orcid.org/0000-0001-7059-966X
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SUPPORTING INFORMATION
Additional Supporting Information may be found online
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Synthesis, spectroscopic studies, thermal properties
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