Synthesis and characterization of a manganese(II) complex containing N(sp 2)4-donor Schiff base ligand and interaction toward biomacromolecules

Article abstract of DOI:10.1080/24701556.2020.1852250

In this work, an N₄-donor Schiff base ligand, N,N'-(propane-1,2-diyl)bis(1-phenyl-1-(pyridin-2-yl)methanimine) (PPPM) and its Mn(II) complex, [Mn(PPPM)(OAc)₂]·3H₂O (1), were prepared and identified by elemental analysis, FT-IR, ¹H NMR spectroscopy as well single-crystal X-ray diffraction. X-ray structure analysis of 1 revealed a distorted square-face bicapped trigonal prism geometry around manganese atom with MnN₄O₄ environment containing an N₄-donor PPPM and two O₂-donor acetato ligands. The ligand has a chiral center on carbon atom which leads to the formation of a racemic mixture of complex 1. In the crystal structure of complex, intermolecular hydrogen bonds form R₄⁴(8) hydrogen bond motifs. The ability of two optical isomers of PPPM ligand and manganese complex to interact with 10 selected biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS, Top II, B-DNA) was investigated by docking studies. These studies revealed that PPPM^R,S and 1 ^R,S isomers can bind to these molecules better than doxorubicin (except B-DNA).

Full text of DOI:10.1080/24701556.2020.1852250

Inorganic and Nano-Metal Chemistry
ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/lsrt21
Synthesis and characterization of a manganese(II)
complex containing N(sp 2)4-donor Schiff base
ligand and interaction toward biomacromolecules
Mohammad Hakimi , Behjat Tarani , Zahra Mardani , Hassan Hassani ,
Monika Kučeráková & Eliska Skorepova
To cite this article: Mohammad Hakimi , Behjat Tarani , Zahra Mardani , Hassan Hassani ,
Monika Kučeráková & Eliska Skorepova (2020): Synthesis and characterization of a manganese(II)
complex containing N(sp 2)4-donor Schiff base ligand and interaction toward biomacromolecules,
Inorganic and Nano-Metal Chemistry, DOI: 10.1080/24701556.2020.1852250
To link to this article: https://doi.org/10.1080/24701556.2020.1852250
View supplementary material
Published online: 02 Dec 2020.
Submit your article to this journal
Article views: 11
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at
https://www.tandfonline.com/action/journalInformation?journalCode=lsrt21

INORGANIC AND NANO-METAL CHEMISTRY
https://doi.org/10.1080/24701556.2020.1852250
Synthesis and characterization of a manganese(II) complex containing N(sp2)4-
donor Schiff base ligand and interaction toward biomacromolecules
a
ꢀ ꢁ ꢁc
Mohammad Hakimia, Behjat Tarania, Zahra Mardanib , Hassan Hassani , Monika Kucerakova , and
Eliska Skorepovac
b
aDepartment of Chemistry, Payame Noor University, Tehran, Iran; Inorganic Chemistry Department, Faculty of Chemistry, Urmia University,
c
Urmia, Iran; Institute of Physic, Czech Academy of Sciences, Prague, Czech Republic
ABSTRACT
ARTICLE HISTORY
Received 12 May 2020
Accepted 18 October 2020
In this work, an N4-donor Schiff base ligand, N,N’-(propane-1,2-diyl)bis(1-phenyl-1-(pyridin-2-yl)metha-
nimine) (PPPM) and its Mn(II) complex, [Mn(PPPM)(OAc)2]ꢀ3H2O (1), were prepared and identified by
1
elemental analysis, FT-IR, H NMR spectroscopy as well single-crystal X-ray diffraction. X-ray structure
KEYWORDS
Manganese(II) complex;
docking study;
biomacromolecule; Schiff
base; crystal structure
analysis of 1 revealed a distorted square-face bicapped trigonal prism geometry around manganese
atom with MnN4O4 environment containing an N4-donor PPPM and two O2-donor acetato ligands.
The ligand has a chiral center on carbon atom which leads to the formation of a racemic mixture of
4
complex 1. In the crystal structure of complex, intermolecular hydrogen bonds form R4 (8) hydrogen
bond motifs. The ability of two optical isomers of PPPM ligand and manganese complex to interact
with 10 selected biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS, Top
II, B-DNA) was investigated by docking studies. These studies revealed that PPPMR,S and 1R,S isomers
can bind to these molecules better than doxorubicin (except B-DNA).
Introduction
Manganese, with rich coordination geometry and versatile
oxidation state, is well known biogenic metal and
entrenched in the medicine and biology areas.[26]
Manganese is a necessary element occurring in the biological
systems and tis trace amounts are essential to life.[27] Thus,
many manganese complexes derived from Schiff base have
been synthesized and evaluated for their applications as bio-
medical field.[28,29] Some manganese complexes have shown
considerable promise in superoxide dismutase (SOD) and
catalase-like activity which could be a perspective for the
Schiff base compounds attract considerable interest due to
their wide range of applications such as chemosensors,[1,2]
OLED,[3] photochromic materials,[4] catalysts,[5–7] and anti-
corrosion agents.[8] Schiff base ligands and their complexes
show interesting pharmacological activities such as anti-
microbial,[9] anticancer,[10,11] antibacterial,[12] antifungal,[12]
and antioxidative.[13] The cleavage of plasmid DNA by
Schiff base complexes has been well reported.[14,15] Also,
interaction of these compounds with biomacromolecules
have been studied by docking studies.[10,11,16–18]
The coordination complexes as well as their applications
have been largely previously reported in literatures.[19–21]
Transition metals such as copper, iron, and manganese are
involved in multiple biological processes, from electron
transfer to catalysis to structural roles, and are frequently
associated with active sites of proteins and enzymes.[22]
However, dysregulation of some of these essential metals
during normal biochemical processing has been implicated
in the development of various pathological disorders, such
as cancer.[23] The research shows that the metal ion is the
most significant factor in the design of medicine Schiff base
complexes.[24] An important property of metals is that they
form positively charged ions in aqueous solution that can
bind to negatively charged biological molecules.[22,25]
creation of new medicines with wide applications.[30,31]
A
variety of activities such as inhibit endogenous NMT,[32]
HAS[33] and BSA[27,34] binding, antioxidant,[35] anti-
cancer,[36,37] antimicrobial[37] has been observed for com-
plexes of manganese. Also interaction of these complexes
with DNA has been established by experimental[38,39] and
theoretical (docking) methods[17] and researchers have
established that these compounds can overcome drug resist-
ant cancers.[40]
In order to extend the chemistry of this class of com-
pounds, in this work, preparation, characterization (elemen-
tal analysis, FT-IR, 1H NMR spectroscopy) and crystal
structure of a manganese(II) complex, [Mn(PPPM)(OAc)2]
ꢀ3H2O (1), with N,N’-(propane-1,2-diyl)bis(1-phenyl-1-(pyri-
din-2-yl)methanimine) (PPPM) ligand (Scheme 1)
are presented.
CONTACT Mohammad Hakimi
Supplemental data for this article can be accessed at the publisher’s website.
CCDC Number 1941242 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/
mohakimi@yahoo.com
Department of Chemistry, Payame Noor University, 19395-4697 Tehran, Iran.
conts/retrieving.html or from the Cambridge Crystallographic Data Center, 12, Union Road, Cambridge CB2 1EZ, UK.
deposit@ccdc.cam.ac.uk.
ß 2020 Taylor & Francis Group, LLC

2
M. HAKIMI ET AL.
Scheme 1. Structure of the N,N’-(propane-1,2-diyl)bis(1-phenyl-1-(pyridin-2-yl)methanimine) (PPPM) ligand with atom numbering.
In addition to the expected biological properties of the dissolved in methanol (5 mL), was added dropwise with stirring to
Schiff base ligand PPPM, binding to Mn2þ ion makes this
0.37 g (2 mmol) of 2-benzoylpyridine in methanol (20 mL) and
complex a good choice for biologically active compounds.
For study of the biological activities of two possible isomers
(R and S) of PPPM and also 1, docking calculations were
run to investigate the possibility of an interaction between
these compounds with 10 protein targets,[10,16,18,41–43]
including: BRAF kinase, Cathepsin B (CatB), DNA gyrase,
Histone deacetylase (HDAC7), recombinant Human albu-
min (rHA), Ribonucleotide reductases (RNR), Thioredoxin
the resulting solution was stirred for 1 h at room temperature and
then was refluxed for 6 h. A thick brown oil was obtained and the
redundant precursors removed by rotary evaporation. Yield:
0.32 g, 79%. Anal. Calcd for C27H24N4 (404.52): C, 80.17; H, 5.98;
N, 13.85. Found C, 79.19; H, 6.12; N, 14.07. IR (KBr disk): 3053 (ꢀ
C–H)ar, 2963 (ꢀas C–H), 1663 (ꢀ C¼ N)imine, 1628 (ꢀ C¼ N)py,
1566 (ꢀ C¼ C)ar, 1449 (das CH2), 1395 (ds CH2), 1045 (ꢀ C–N),
750 and 700 (c py) cmꢁ1 1H NMR (250MHz, DMSO-d6):
.
d ¼ 8.70 (d, 2H, C1H, C13H), 8.44 (d, 2H, C4H, C16H), 7.15–8.03
(m, 14H, CHar), 2.99–3.23 (m, 2H, C25H2), 2.30–2.40 (m, 1H,
C26H), 1.03 (d, 3H, C27H3) ppm.
reductase
(TrxR),
Thymidylate
synthase
(TS),
Topoisomerase II (Top II) along with B-DNA. These pro-
teins were selected either due to their reported roles in can-
cer growth or as transport agents that affect drug
pharmacokinetic properties (e.g. rHA). The DNA gyrase was
included to study the possibility of anticancer properties and
their activity as antimalarial agents.[44] The knowledge
gained from docking on the B-DNA should be useful for
the development of potential probes for DNA structure and
new therapeutic agents for cancer and other diseases.[45]
Preparation of [Mn(PPPM)(OAc)2]ꢀ3H2O
Mn(OAc)2 (1 mmol, 0.17 g) was dissolved in methanol
(5 ml) and added with stirring to the methanol solution
(10 ml) of the PPPM (1 mmol, 0.40 g). The reaction mixture
was stirred at 60 ꢂC for 4 h. The solution was left for slow
evaporation at room temperature. Then the resultant pre-
cipitate was filtered off, washed with methanol, and recrys-
tallization from acetonitrile. After six days, brown crystals of
complex were formed and collected by filtration. Yield
0.52 g, 82%. M.p. 156 ꢂC. Anal. Calcd for C31H36MnN4O7
Experimental
Materials and measurements
All starting chemicals and solvents were reagent or analytical
grade and used as received. The infrared spectra of KBr pel-
lets in the range of 400–4000 cmꢁ1 were recorded with a (631.6): C, 58.95; H, 5.75; N, 8.87. Found C, 59.05; H, 5.78;
FT-IR 8400-Shimadzu spectrometer. The carbon, hydrogen,
and nitrogen contents were determined in a Thermo
Finnigan Flash Elemental Analyzer 1112 EA. The melting
points were determined with a Barnsted Electrothermal 9200
electrically heated apparatus. 1H NMR spectrum was
recorded on a Bruker Aspect 3000 instrument operating at
250 MHz; chemical shifts are given in parts per million, with
values in reference to an internal standard of TMS.
N, 9.08. IR (KBr): 3391 (ꢀas O–H), 3301 (ꢀs O–H), 3057 (ꢀ
C–H)ar, 2958 (ꢀas CH2 and/or CH3), 2930 (ꢀs CH2 and/or
CH3), 1656 (d H2O), 1636 (ꢀ C ¼ N)imine, 1578 (ꢀ C ¼ N)py,
1567 (ꢀ C ¼ C)ar, 1565 (ꢀas COO)Oac, 1437 (ꢀs COO)Oac
,
1430 (das CH2), 1395 (ds CH2), 1049 (ꢀ C–N), 750 and 708
(c py), 667 (d OCO)Oac, 629 (qr H2O), 550 (qw H2O) cmꢁ1
.
Computational details
Preparation of N,N’-(propane-1,2-diyl)bis(1-phenyl-1-
(pyridin-2-yl)methanimine), PPPM
The structure of ligand was optimized with the Gaussian 09
software[47] and calculated for an isolated molecule using
Density Functional Theory (DFT)[48] at the B3LYP/6-31 þ G
The PPPM ligand was prepared as described in literature[46] with
some modifications. 0.07 g (1 mmol) of 1,2-diaminopropane, level of theory (Figure 1).

INORGANIC AND NANO-METAL CHEMISTRY
3
Figure 1. Optimized structure of the PPPM.
Table 1. Crystal structure data and structure refinement of complex 1.
Empirical formula
C31H36MnN4O7
Formula weight, g mol–1
Crystal size, mm3
Temperature, K
Crystal system
Space group
Unit cell dimensions
a, Å
631.6
0.12 ꢃ 0.08 ꢃ 0.05
95
Monoclinic
C 2/c
24.7851(3)
b, Å
c, Å
8.2661(1)
29.9111(4)
99.1923(12)
6049.37(13)
ꢂ
b,
Volume, Å3
Z
8
Calculated density, g cm–3
Absorption coefficient, mm–1
F(0 0 0), e
1.387
4.00
2648
3.6–74.3
ꢂ
h range data collection,
h, k, l ranges
ꢁ30 ꢄ h ꢄ 30, ꢁ10 ꢄ k ꢄ 10, ꢁ36 ꢄ l ꢄ 37
Reflections collected/independent/Rint
Data/ref. parameters
R1/wR2 (I > 3r(I))
43,147/6149 / 0.037
6149/413
0.0334/0.0817
0.0357/0.0825
2.12
0.40/ꢁ0.46
R1/wR2 (all data)
Goodness-of-fit on F2
Largest diff. peak/hole, e Å–3
Docking details
the protein residues within 6 Å of the reference ligand “A”
that accompanied the downloaded protein. For B-DNA, the
region of interest was defined on DNA backbone within
10 Å of the O2, DT19 atom for minor groove. All free water
molecules in the structure of the proteins were deleted
before docking. Default values of all other parameters were
used and the compounds were submitted to 10 genetic algo-
rithm runs using the GOLDScore fitness function.
The pdb files 4r5y, 3ai8, 5cdn, 3c0z, 2bx8, 1peo, 3qfa, 1njb,
4gfh, 1bna for the 10 receptors, BRAF kinase, Cathepsin B
(CatB), DNA gyrase, Histone deacetylase (HDAC7), recom-
binant Human albumin (rHA), Ribonucleotide reductases
(RNR), Thioredoxin reductase (TrxR), Thymidylate synthase
(TS), Topoisomerase II (Top II), B-DNA, respectively, used
in this research were obtained from the Protein Data Bank
(pdb).[49] The full version of Genetic Optimization for
Ligand Docking (GOLD) 5.5[50] was used for the docking
studies. The Hermes visualizer in the GOLD Suite was used
to further prepare the ligand, complex, and the receptors for
docking. The cif file of the complex and optimized structure
of ligand (Figure 1) were used for the docking studies. The
Crystal structure determination
A suitable crystal of 1 was chosen and its X-ray analysis was
performed at 95 K using a SuperNova diffractometer with a
micro-focus sealed tube, mirrors-collimated Cu Ka radiation
region of interest used for GOLD docking was defined as all (k ¼ 1.54184 Å), and CCD detector Atlas S2. The data were

4
M. HAKIMI ET AL.
Table 2. Selected bond lengths (Å) and angles (ꢂ) for complex 1 with esti-
mated standard deviations in parentheses.
coordination to the manganese, confirming the N4-donation
of the ligand. Similar result has been observed for PPPM
derivatives.[17]
Bond lengths
Angles
Mn1–N1
Mn1–N2a
Mn1–N3
Mn1–N4a
Mn1–O1
Mn1–O2
Mn1–O3
Mn1–O4
2.392(1)
2.372(3)
2.359(1)
2.341(7)
2.360(1)
2.348(1)
2.397(1)
2.288(1)
N1–Mn1–N2a
N1–Mn1–N3
N1–Mn1–O2
O1–Mn1–O2
O2–Mn1–O4
O3–Mn1–O1
O3–Mn1–O2
O3–Mn1–O4
67.27(8)
155.61(4)
94.61(4)
55.25(4)
165.53(5)
83.30(4)
138.18(4)
55.37(5)
The presence of the water molecule in 1 affects the IR
spectrum in three regions, including broad peaks above
3300–3400 cmꢁ1 for asymmetric and symmetric O–H
stretches, 1656 cmꢁ1 for H2O bending and 200–600 cmꢁ1 for
“librational modes”. These modes are due to rotational oscil-
lations of the water molecules restricted by interactions with
neighboring atoms and they are classified into three types
(wagging (qw), twisting (qt), and rocking (qr)) depending
upon the direction of the principal axis of rotation.[12,13]
In the FT-IR spectrum of 1, three bands at 1565, 1437,
and 667 cmꢁ1 were assigned to the ꢀas (COO), ꢀs (COO),
and d (OCO) respectively,[59] confirming the presence of the
acetate unit in this complex. The differences between asym-
metric (ꢀas) and symmetric (ꢀs) stretching of the acetate
group (D) can reveal its coordination type. Compared with
D value for the acetate salt, monodentate complexes exhibit
much larger D values (164 cmꢁ1) while in bidentate com-
plexes these values are significantly lower.[60,61] The D value
for 1 is calculated as 128 cmꢁ1 which corresponds to the
bidentate acetate ligand.
Table 3. Hydrogen bond dimensions (Å and ꢂ) in complex 1.a
D–HꢀꢀꢀA
d(D–H)
d(HꢀꢀꢀA)
d(DꢀꢀꢀA)
<(DHA)
O5–H1o5ꢀꢀꢀO4i
O5–H2o5ꢀꢀꢀO2
O6–H1o6ꢀꢀꢀO7ii
O6–H2o6ꢀꢀꢀO1iii
O7–H1o7ꢀꢀꢀO3iv
O7–H2o7ꢀꢀꢀO6
0.87
0.83
0.95
0.95
0.95
0.952
1.94
2.14
1.88
1.77
1.87
1.852
2.813(2)
2.9665(19)
2.818(2)
2.713(2)
2.795(2)
2.774(2)
176
176
172
174
163
162
aSymmetry operators: i ꢁx þ 1/2, y ꢁ 1/2, ꢁz þ 1/2; ii ꢁx þ 3/2, ꢁy þ 1/2, ꢁz;
iii x þ 1/2, y ꢁ 1/2, z; iv ꢁx þ 1, y, ꢁz þ 1/2.
processed with CrysAlis.[51] The structure was solved with
the charge flipping algorithm by Superflip[52] and refined by
full-matrix least-squares on F2 using program Jana2006.[53]
Anisotropic displacement parameters were used for all non-
hydrogen atoms. Hydrogen atoms on carbon were kept at
geometrically expected positions and refined as riding atoms
with Uiso ¼ 1.2 Ueq of the corresponding parent atom.
Positions of hydrogen atoms on water were found in the
residual electron density map using the software MCE[54]
and refined using a restraint that all O–H bond lengths
should be close to 0.95 Å. For hydrogen atoms of water, Uiso
was kept as 1.2 Ueq of the corresponding parent oxygen. The
middle bridging part of the ligand was disordered
(N4–C30–C29–(C31)–C30–N2). The disorder was modeled
using the rigid body refinement feature in Jana2006 and the
occupancy of the major component was 0.590(2).
1
The H NMR spectrum of the PPPM revealed that this
structure is containing the aromatic (7.5–9.0 ppm) and ali-
phatic (5.19 ppm) portions. Among the aromatic protons,
the nearest one to the nitrogen atom of the pyridine ring is
observed at the lowest magnetic field.
Crystal and molecular structure of
[Mn(PPPM)(OAc)2]ꢀ3H2O
In the crystal structure of 1 (Figure 2), the manganese atom
is coordinated by four nitrogen atoms of one PPPM and
four oxygen atoms of two bidentate acetato ligands to form
a distorted square-face bicapped trigonal prism, MnN4O4
(Figure 3), geometry. Study of the CSD database[62] revealed
that this environment is rare and there are only nine exam-
ples[17,63–69] for such geometry around the manganese atom,
in which all nitrogen atoms belong to one tetradentate lig-
and. In this structure, bond lengths average of four Mn–N
(2.366 Å) is comparable with that of the Mn–O (2.348 Å)
Selected crystallographic data are presented in Table 1.
Diagrams of the molecular structure were created using
Ortep-III[55,56] and Diamond.[57] Selected bond lengths are
displayed in Table 2 and hydrogen bond geometries in
Table 3.
bond lengths.
Results and discussion
py
In 1, the PPPM ligand acts as a tetradentate N2imineN2
-
The PPPM ligand was prepared by the condensation of pro-
pane-1,2-diamine and 2-benzoyl pyridine. Reaction between
manganese(II) acetate with PPPM provided complex 1. The
complex is air-stable and soluble in DMSO.
donor, forming three five-membered chelate rings. Among
them, the central chelate ring is non-planar (r.m.s deviation:
0.262 Å for C30a) while two side rings are almost planar
(r.m.s deviations: 0.078 Å for C6, 0.089 Å for N4a). The
dihedral angle between planes through the four coordinated
nitrogen atoms and four coordinated oxygen atoms is
86.29ꢂ, confirming that the PPPM ligand has perpendicular
direction to the acetato ligands. Also, two pyridine rings lie
on a plane formed by four coordinated nitrogen atoms
(dihedral angles average of 4.10ꢂ), while phenyl rings are
rotated by 76.65ꢂ (angles average) from this plane. The
PPPM ligand has a chiral center on C29 atom and the crys-
Spectroscopic studies
In the IR spectrum of the PPPM and 1, bands at above and
below 3000 cmꢁ1 are due to the C–H modes of the aromatic
rings (phenyl and pyridine) and aliphatic moieties (propane
moiety and acetato ligand), respectively. The imine and pyri-
dine units of the ligand are effected the IR spectrum at
about 1650 cmꢁ1 owing to the ꢀ (C ¼ N).[58] These bands tals of 1 are a racemic mixture of R and S isomers in alter-
are shifted by 27 and 50 cmꢁ1 to lower frequencies after nate layers. In fact, there is a crystallographic disorder in the

INORGANIC AND NANO-METAL CHEMISTRY
5
Figure 2. Ortep-III diagram of the molecular structure of complex 1. The ellipsoids are drawn at the 50% probability level.
Figure 3. Packing of molecules 1 in the crystal showing the hydrogen bonds and R44(8) hydrogen bond motifs. Each MnN4O4 unit is shown as a polyhedron.

6
M. HAKIMI ET AL.
Table 4. The calculated fitness values for the optical isomers of PPPM ligand and complex 1 along with the doxorubicin.
B-DNA
MIN
BRAF-KINASE
CATB
DNA-GYRASE
HDAC7
RHA
RNR
TRXR
TS
TOP II
PPPMR
65.20
68.91
49.89
51.95
83.10
60.84
57.52
47.28
49.49
54.21
46.54
56.47
35.32
54.84
25.95
69.29
52.18
71.90
44.10
52.97
69.01
69.17
58.94
42.65
50.73
57.99
58.47
60.13
50.43
50.10
55.84
55.45
47.17
36.91
49.18
71.63
43.39
–1.39
34.05
66.70
58.58
55.61
60.55
60.01
53.34
62.27
65.73
66.71
65.68
59.05
PPPMS
COMPLEX 1S
COMPLEX 1R
DOXORUBICIN
Figure 4. Docking study results showing the interaction between the PPPMR and B-DNA (minor groove).
PPPM ligand atoms N4–C30–C29–(C31)–C30–N2 (the terms of the values of fitness, where “fitness” expresses abil-
bringing section of PPPM). The molecule of PPPM is almost ity of the investigated compound to take part in the docking
interaction.[10,16,17,41–43,73] In Table 4, we present the best
symmetrical with only the methyl C31 violating this. This
then enables the ligand to bind to the metal in the lattice in
a disordered fashion, where both enantiomers are overlaid
and the refined occupancy of the major component
is 0.590(2).
binding results out of the favorable ten ones predicted by
Gold, and compare the obtained scores with those of the
famous anticancer drug, doxorubicin (a cancer medication
that interferes with the growth and spread of cancer cells in
the body[74]).
Analysis of Table 4 shows that all studied structures can
be consider as biologically active compounds.[10,16,17,41–43,73]
The best predicted targets for 1S, 1R, PPPMS, and PPPMR
are DNA gyrase, Top II, HDAC7, and TrxR, respectively.
This observation revealed that the presence of a chiral atom
on PPPM ligand highly affected binding ability of the corre-
sponding optical isomers. Based on the calculated fitness
values, ligand and its complex show different tendency to
the protein molecules, for example one or two isomers of
PPPM can interact with the BRAF Kinase, CatB, HDAC7,
RNR, and TrxR proteins better than the 1 while the complex
isomers bind to the other proteins stronger than the ligand
In this structure, there are strong O–HꢀꢀꢀO hydrogen
bonds (strong hydrogen bonds are in range of 1.5–2.2 Å[70]),
between water molecules as well as between water and the
acetato ligand. The O–HꢀꢀꢀO hydrogen bonds participate in
4
the formation of a R4 (8) hydrogen bond motif (four accept-
ors, four donors with degree of 8)[71,72] between four water
molecules (Figure 3).
Docking studies
For the prediction and comparison of the biological activity
of the ligand and complex 1 along with their two possible
optical isomers, interactions of these four compounds with
10 macromolecule receptors using Gold[50] docking software isomers. Docking studies revealed that the optical isomers of
were studied. The Gold docking results are reported in ligand and complex have different binding abilities and can

INORGANIC AND NANO-METAL CHEMISTRY
7
Figure 5. Docking study results showing the interaction between the Complex 1S and B-DNA (minor groove).
attach selectively to the biomacromolecules. Also these com- for 1S, 1R, PPPMS, and PPPMR are DNA gyrase, Top II,
pounds can place in the minor groove of the DNA molecule HDAC7, and TrxR, respectively. This study showed that two
which make these compounds a good choice for DNA bind- optical isomers of ligand and complex have different ten-
ing studies. Data of the Table 4 revealed that the isomers of
ligand or complex 1 or both of them have higher fitness val-
ues than doxorubicin in interaction toward all studied tar-
gets (except B-DNA), therefore we suggest that anticancer
activities of these compounds should be studied. The dock-
ing results of the interaction between the PPPMR and com-
plex 1S with B-DNA (minor groove) are shown in Figures 4
and 5, respectively.
dency to bimacromolecules. Docking calculations revealed
that the fitness values of the ligand and complex are higher
than that of doxorubicin (except B-DNA), thus we suggest
that studying anticancer activities of these compounds could
bring interesting results.
Acknowledgements
˚
MD and MK thank Tereza Vꢁaclavu from the Institute of Physics for
measurement of the data set of complex 1. The crystallographic part
was supported by the project 18-10504S of the Czech Science
Foundation and used instruments of the CzechNanoLab Research
Infrastructure supported by MEYS CR (LM2018110). We would like to
acknowledge Dr. Keyvan Moeini for CSD studies and the FAIRE
(Frank H. Allen International Research and Education Programme)
award of the Cambridge Structural Database, for supplying the access
to the CSD softwares package.
Conclusion
In this work,
a
new complex of manganese(II),
[Mn(PPPM)(OAc)2]ꢀ3H2O (1), with N,N’-(propane-1,2-diyl)-
bis(1-phenyl-1-(pyridin-2-yl)methanimine) (PPPM) was syn-
thesized and spectral properties of the complex as well as
the ligand were investigated. In the structure of 1, the man-
ganese atom has a MnN4O4 environment with a distorted
square-face bicapped trigonal prism geometry formed by
one N4-donor PPPM ligand and two O2-donor acetato
ligands. In the crystal packing of 1, the strong O–HꢀꢀꢀO
Disclosure statement
No potential conflict of interest was reported by the authors.
4
interactions form a R4 (8) hydrogen bond motif between
four water molecules. The docking studies on the complex
and its ligand revealed that these compounds might be bio-
logically active by interacting with 10 biomacromolecules
(BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR,
Funding
The crystallographic part was supported by the project 18-10504S of
the Czech Science Foundation using instruments of the ASTRA labora-
tory established within the Operation Program Prague Competitiveness
TrxR, TS, Top II, and B-DNA). The best predicted targets – project CZ.2.16/3.1.00/24510.

8
M. HAKIMI ET AL.
Bis[Pyridine-2-Methylene]-Thiocarbohydrazone
Ligand. Spectrochim. Acta A Mol. Biomol. Spectrosc. 2011, 79,
1050–1056. DOI: 10.1016/j.saa.2011.04.018.
Schiff-Base
ORCID
Zahra Mardani
http://orcid.org/0000-0002-3749-5399
16. Mardani, Z.; Hakimi, M.; Moeini, K.; Mohr, F. Reaction of 2-
[(2-Aminoethyl)Amino]Ethanol with Pyridine-2-Carbaldehyde
and Complexation of the Products with Cu(II) and Cd(II) along
with Docking Studies. Acta Crystallogr. 2019, C75, 951–959.
References
1. Dong, W.-K.; Li, X.-L.; Wang, L.; Zhang, Y.; Ding, Y.-J. A New
Application of Salamo-Type Bisoximes: As a Relay–Sensor for
Zn2þ/Cu2þ and Its Novel Complexes for Successive Sensing of
Hþ/OHꢁ. Sensor. Actuat. 2016, B229, 370–378.
ꢀ ꢁ
ꢁ
17. Hakimi, M.; Tarani, B.; Mardani, Z.; Moeini, K.; Kucerakova, M.;
ꢀ
Dusek, M. Spectral, Structural, Theoretical and Docking Studies
of a Mn(II) Complex with an N4-Donor Ligand. J. Chem. Res.
2018, 42, 623–627. DOI: 10.3184/174751918X15422215897056.
18. Hakimi, M.; Ahmadi, S.; Mardani, Z.; Mohr, F. Docking Studies
on an N4-Donor Schiff Base Ligand and Its Cu(II) Complex
Supported by Structural, Spectral and Theoretical Studies. J.
Chem. Res. 2019, 43, 170–178. DOI: 10.1177/1747519819857505.
19. Fan, L.; Liu, Z.; Zhang, Y.; Wang, F.; Zhao, D.; Yang, J.; Zhang,
X. Electrochemical, and Magenetic Properties of 2D
Coordination Polymers Based on the Mixed Ligands p-
2. Wang, B.-J.; Dong, W.-K.; Zhang, Y.; Akogun, S. F. A. Novel
Relay-Sensor for Highly Sensitive and Selective Detection of
Zn2þ/Pic ꢁ and Fluorescence on/off Switch Response of Hþ/
OHꢁ. Sensor. Actuat. 2017, B247, 254–264.
3. Che, C.-M.; Chan, S.-C.; Xiang, H.-F.; Chan, M. C. W.; Liu, Y.;
Wang, Y. Tetradentate Schiff Base Platinum(II) Complexes as
New Class of Phosphorescent Materials for High-Efficiency and
White-Light Electroluminescent Devices. Chem. Commun. 2004,
1484–1485. DOI: 10.1039/b402318h.
Terphenyl-2,200,500,5000-Tetracarboxylate
Acid
and
1,10-
Phenanthroline. New J. Chem. 2019, 43, 13349–13356. DOI: 10.
1039/C9NJ03530C.
4. Margerum, J. D.; Miller, L. J. Photochromism; Interscience,
Wiley: New York, 1971; p 569.
5. Gupta, K. C.; Sutar, A. K. Catalytic Activities of Schiff Base
Transition Metal Complexes. Coord. Chem. Rev. 2008, 252,
1420–1450. DOI: 10.1016/j.ccr.2007.09.005.
6. Kannappan, R.; Matsumoto, M.; Hallren, J.; Nicholas, K. M. New
Chiral Schiff Base–Zinc Complexes and Their Esterolytic
Catalytic Activity. J. Mol. Catal. 2011, A339, 72–78.
20. Fan, L.; Zhang, Y.; Liang, J.; Wang, X.; Lv, H.; Wang, J.; Zhao,
L.; Zhang, X. Structural Diversity, Magnetic Properties, and
Luminescence Sensing of Five 3D Coordination Polymers
Derived from Designed 3,5-Di(20,40-Dicarboxylphenyl)Benozoic
Acid. CrystEngComm 2018, 20, 4752–4762. DOI: 10.1039/
C8CE00877A.
21. Fan, L.; Wang, F.; Zhao, D.; Sun, X.; Chen, H.; Wang, H.;
Zhang, X. Two Cadmium(II) Coordination Polymers as Multi-
Functional Luminescent Sensors for the Detection of Cr(VI)
Anions, Dichloronitroaniline Pesticide, and Nitrofuran Antibiotic
in Aqueous Media. Spectrochim. Acta A Mol. Biomol. Spectrosc.
2020, A239, 118467 DOI: 10.1016/j.saa.2020.118467.
7. Li, L.-H.; Dong, W.-K.; Zhang, Y.; Akogun, S. F.; Xu, L.
Syntheses, Structures and Catecholase Activities of Homo- and
Hetero-Trinuclear Cobalt(II) Complexes Constructed from an
Acyclic Naphthalenediol-Based Bis(Salamo)-Type Ligand. Appl.
Organometal. Chem. 2017, 31, e3818. DOI: 10.1002/aoc.3818.
8. Ahamad, I.; Prasad, R.; Quraishi, M. A. Thermodynamic,
Electrochemical and Quantum Chemical Investigation of Some
Schiff Bases as Corrosion Inhibitors for Mild Steel in
Hydrochloric Acid Solutions. Corros. Sci. 2010, 52, 933–942.
DOI: 10.1016/j.corsci.2009.11.016.
9. Zhang, M.; Xian, D.-M.; Li, H.-H.; Zhang, J.-C.; You, Z.-L.
Synthesis and Structures of Halo-Substituted Aroylhydrazones
with Antimicrobial Activity. Aust. J. Chem. 2012, 65, 343–350.
DOI: 10.1071/CH11424.
10. Saghatforoush, L.; Moeini, K.; Hosseini-Yazdi, S. A.; Mardani, Z.;
Hajabbas-Farshchi, A.; Jameson, H. T.; Telfer, S. G.; Woollins,
J. D. Theoretical and Experimental Investigation of Anticancer
Activities of an Acyclic and Symmetrical Compartmental Schiff
Base Ligand and Its Co(II). RSC Adv. 2018, 8, 35625–35639.
DOI: 10.1039/C8RA07463A.
11. Saghatforoush, L.; Moeini, K.; Hosseini-Yazdi, S. A.; Mardani, Z.;
Bakhtiari, A.; Hajabbas-Farshchi, A.; Honarvar, S.; Abdelbaky,
M. S. M. Effective Anticancer Activities of an Acyclic
Symmetrical Compartmental Schiff Base Ligand and Its Co(II),
Cu(II) and Zn(II) Complexes against the Human Leukemia Cell
Line K562. Polyhedron 2019, 170, 312–324. DOI: 10.1016/j.poly.
2019.05.057.
12. Shanker, K.; Rohini, R.; Ravinder, V.; Reddy, P. M.; Ho, Y.-P.
Ru(II) Complexes of N4 and N2O2 Macrocyclic Schiff Base
Ligands: Their Antibacterial and Antifungal Studies. Spectrochim.
Acta A Mol. Biomol. Spectrosc. 2009, 73, 205–211. DOI: 10.1016/
j.saa.2009.01.021.
13. Li, Y.; Yang, Z.-Y. DNA Binding Affinity and Antioxidative
Activity of Copper(II) and Zinc(II) Complexes with a Novel
Hesperetin Schiff Base Ligand. Inorg. Chim. Acta 2009, 362,
4823–4831. DOI: 10.1016/j.ica.2009.07.008.
14. Morrow, J. R.; Kolasa, K. A. Cleavage of DNA by Nickel
Complexes. Inorg. Chim. Acta 1992, 195, 245–248. DOI: 10.
1016/S0020-1693(00)85319-0.
22. Orvig,
C.;
Abrams,
M.
J.
Medicinal
Inorganic
Chemistry: Introduction. Chem. Rev. 1999, 99, 2201–2204. DOI:
10.1021/cr980419w.
23. Yaman, M.; Kaya, G.; Yekeler, H. Distribution of Trace Metal
Concentrations in Paired Cancerous and Non-Cancerous Human
Stomach Tissues. World J. Gastroenterol. 2007, 13, 612–618.
DOI: 10.3748/wjg.v13.i4.612.
24. Arjmand, F.; Muddassir, M.; Khan, R. H. Chiral Preference of I-
Tryptophan Derived Metal-Based Antitumor Agent of Late 3d-
Metal Ions (Co(II), Cu(II) and Zn(II)) in Comparison to d- and
dl-Tryptophan Analogues: Their in Vitro Reactivity Towards CT
DNA, 50-GMP and 50-TMP. Eur. J. Inorg. Chem. 2010, 45,
3549–3557.
25. Haas, K. L.; Franz, K. J. Application of Metal Coordination
Chemistry to Explore and Manipulate Cell Biology. Chem. Rev.
2009, 109, 4921–4960. DOI: 10.1021/cr900134a.
ꢁ
ꢁ
26. Rebouc¸as, J. S.; Spasojevic, I.; Batinic-Haberle, I. Pure
Manganese(III) 5,10,15,20-Tetrakis(4-Benzoic Acid)Porphyrin
(MnTBAP) is Not a Superoxide Dismutase Mimic in Aqueous
Systems:
A Case of Structure–Activity Relationship as a
Watchdog Mechanism in Experimental Therapeutics and
Biology. J. Biol. Inorg. Chem. 2008, 13, 289–302. DOI: 10.1007/
s00775-007-0324-9.
27. Li, Z.; Yan, H.; Liu, K.; Huang, X.; Niu, M. Syntheses, Structures,
DNA/BSA Binding and Cytotoxic Activity Studies of Chiral
Alcohol-Amine Schiff Base Manganese (II/III) Complexes. J.
Mol. Struct. 2019, 1195, 470–478. DOI: 10.1016/j.molstruc.2019.
05.110.
28. Dehkordi, M. N.; Bordbar, A. K.; Lincoln, P.; Mirkhani, V.
Spectroscopic Study on the Interaction of ct-DNA with
Manganese Salen Complex Containing Triphenyl Phosphonium
Groups. Spectrochim. Acta A Mol. Biomol. Spectrosc. 2012, 90,
50–54. DOI: 10.1016/j.saa.2012.01.015.
29. Zhu, L.-N.; Gao, H.-R.; Wang, H.-X.; Xu, M.-Y.; Li, X.-Z.
Synthesis, Crystal Structures, and DNA Cleavage Activities of
Manganese(II) Complexes: A Good Example of the Synergy
15. Tiwari, A. D.; Mishra, A. K.; Mishra, S. B.; Mamba, B. B.; Maji,
B.; Bhattacharya, S. Synthesis and DNA Binding Studies of
Ni(II), Co(II), Cu(II) and Zn(II) Metal Complexes of N1,N5-

INORGANIC AND NANO-METAL CHEMISTRY
9
between Metal Ions Prompting DNA Cleavage. Eur. J. Inorg. 43. Hakimi, M.; Sadeghi, F.; Feizi, N.; Moeini, K.; Kucerakova, M.;
Dusek, M. Investigation of the Effect of the N-Oxidation Process
on the Interaction of Selected Pyridine Compounds with
Biomacromolecules: Structural, Spectral, Theoretical and
Docking Studies. Acta Crystallogr. 2019, C75, 750–757.
44. Adeniyi, A. A.; Ajibade, P. A. Comparing the Suitability of
Autodock, Gold and Glide for the Docking and Predicting the
Possible Targets of Ru(II)-Based Complexes as Anticancer
Agents. Molecules 2013, 18, 3760–3778. DOI: 10.3390/
molecules18043760.
Chem. 2014, 2014, 2396–2405. DOI: 10.1002/ejic.201400044.
30. Weiss, H.; Riley, D. P. Therapeutic Aspects of Manganese (II)-
Based Superoxide Dismutase Mimics. In Uses of Inorganic
Chemistry in Medicine; The Royal Society of Chemistry:
Cambridge, 1999, pp 77–92.
31. Ghosh, K.; Tyagi, N.; Kumar, P. Role of Carboxamido Nitrogen
in Mononuclear Manganese Complex: Superoxide Scavenging
Activity and Nuclease Activity. Inorg. Chem. Commun. 2010, 13,
380–383. DOI: 10.1016/j.inoche.2009.12.028.
45. Moghadam, N. H.; Salehzadeh, S.; Shahabadi, N. Spectroscopic
and Molecular Docking Studies on the Interaction of Antiviral
Drug Nevirapine with Calf Thymus DNA. Nucleos. Nusleot.
Nucl. 2017, 36, 553–570.
46. Abedi, M.; Khandar, A. A.; Gargari, M. S.; Gurbanov, A. V.;
Hosseini, S. A.; Mahmoudi, G. Syntheses, Characterization, and
Crystal Structures of a Dinuclear Complex and Coordination
Polymer of Mercury(II) with Schiff Base Ligands Containing N3
and N4Donors. Z. Anorg. Allg. Chem. 2014, 640, 2193–2197.
DOI: 10.1002/zaac.201400273.
47. Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.;
Mennucci, B.; Petersson, G. A.; et al. Gaussian 09; Gaussian,
Inc.: Wallingford, CT, 2009.
48. Perdew, J. P. Density-Functional Approximation for the
Correlation Energy of the Inhomogeneous Electron Gas. Phys.
Rev. 1986, B33, 8822–8824.
49. Gavezzotti, A. Are Crystal Structures Predictable? Acc. Chem.
Res. 1994, 27, 309–314. DOI: 10.1021/ar00046a004.
50. Jones, G.; Willett, P.; Glen, R. C.; Leach, A. R.; Taylor, R.
Development and Validation of a Genetic Algorithm for Flexible
Docking. J. Mol. Biol. 1997, 267, 727–748. DOI: 10.1006/jmbi.
1996.0897.
51. Rigaku Oxford Diffraction, CrysAlisPro Software System, Version
1.171.xx.xx; Rigaku Corporation: Oxford, 2018.
52. Palatinus, L.; Chapuis, G. SUPERFLIP – A Computer Program
for the Solution of Crystal Structures by Charge Flipping in
Arbitrary Dimensions. J. Appl. Crystallogr. 2007, 40, 786–790.
DOI: 10.1107/S0021889807029238.
32. Shrivastav, A.; Singh, N. K.; Tripathi, P.; George, T.; Dimmock,
J. R.; Sharma, R. K. Copper(II) and Manganese(III) Complexes
of N’-[(2-Hydroxy Phenyl) Carbonothioyl] Pyridine-2-
Carbohydrazide: Novel Therapeutic Agents for Cancer. Biochim
2006, 88, 1209–1216. DOI: 10.1016/j.biochi.2006.03.004.
33. Geromichalos, G. D.; Tarushi, A.; Lafazanis, K.; Pantazaki, A. A.;
Kessissoglou, D. P.; Psomas, G. In Vitro and in Silico Study of
the Biological Activity of Manganese(III) Inverse-[9-MC-3]-
Metallacrowns and Manganese(II) Complexes with the Anti-
Inflammatory Drugs Diclofenac or Indomethacin. J. Inorg.
Biochem. 2018, 187, 41–55. DOI: 10.1016/j.jinorgbio.2018.07.007.
34. Tarushi, A.; Zampakou, M.; Perontsis, S.; Lafazanis, K.;
Pantazaki, A. A.; Hatzidimitriou, A. G.; Geromichalos, G. D.;
Psomas, G. Manganese(II) Complexes of Tolfenamic Acid or
Naproxen in Polymeric Structures or Encapsulated in [15-MC-5]
Manganese(III) Metallacrowns: Structure and Biological Activity.
Inorg. Chim. Acta 2018, 483, 579–592. DOI: 10.1016/j.ica.2018.
09.001.
€
35. Kaya, B.; Kaya, K.; Koca, A.; Ulku€seven, B. Thiosemicarbazide-
Based Iron(III) and Manganese(III) Complexes. Structural,
Electrochemical Characterization and Antioxidant Activity.
Polyhedron 2019, 173, 114130. DOI: 10.1016/j.poly.2019.114130.
36. Icsel, C.; Yilmaz, V. T.; Aydinlik, S¸.; Aygun, M. New
Manganese(II), Iron(II), Cobalt(II), Nickel(II) and Copper(II)
Saccharinate Complexes of 2,6-Bis(2-Benzimidazolyl)Pyridine as
Potential Anticancer Agents. Eur. J. Inorg. Chem. 2020, 202,
112535.
37. El-Shwiniy, W. H.; Shehab, W. S.; Zordok, W. A. Spectral,
Thermal, DFT Calculations, Anticancer and Antimicrobial
Studies for Bivalent Manganese Complexes of Pyrano[2,3-
d]Pyrimidine Derivatives. J. Mol. Struct. 2020, 1199, 126993.
DOI: 10.1016/j.molstruc.2019.126993.
38. Ghosh, K.; Tyagi, N.; Kumar, P.; Singh, U. P.; Goel, N.
Stabilization of Mn(II) and Mn(III) in Mononuclear Complexes
Derived from Tridentate Ligands with N2O Donors: Synthesis,
Crystal Structure, Superoxide Dismutase Activity and DNA
Interaction Studies. J. Inorg. Biochem. 2010, 104, 9–18. DOI: 10.
1016/j.jinorgbio.2009.09.014.
ꢀꢁꢀ
ꢀ
53. Petrıcek, V.; Dusek, M.; Palatinus, L. Crystallographic
Computing System JANA2006: General Features. ZKRI 2014,
229, 345–352.
54. Rohlicek, J.; Husak, M. MCE2005 – A New Version of a
Program for Fast Interactive Visualization of Electron and
Similar Density Maps Optimized for Small Molecules. J. Appl.
Crystallogr. 2007, 40, 600–601.
55. Farrugia, L. J. ORTEP-3 for Windows – A Version of ORTEP-
III with a Graphical User Interface (GUI). J. Appl. Crystallogr.
1997, 30, 565–565. DOI: 10.1107/S0021889897003117.
39. Sharma, D.; Revanasiddappa, H. D.; Jayalakshmi, B. DNA/BSA
Interaction and In Vitro Antimicrobial Studies of Mn(III)
Complexes Bearing Bidentate N, O Donor Schiff Bases. J. Iran.
Chem. Soc. 2020, 17, 43–58. DOI: 10.1007/s13738-019-01745-9.
40. Ghosh, R. D.; Banerjee, K.; Das, S.; Ganguly, A.; Chakraborty, P.;
Sarkar, A.; Chatterjee, M.; Choudhuri, S. K. A Novel Manganese
Complex, Mn-(II) N-(2-Hydroxy Acetophenone) Glycinate
Overcomes Multidrug-Resistance in Cancer. Eur. J. Pharm. Sci.
2013, 49, 737–747. DOI: 10.1016/j.ejps.2013.05.002.
41. Marandi, F.; Moeini, K.; Alizadeh, F.; Mardani, Z.; Quah, C. K.;
Loh, W.-S.; Woollins, J. D. Treatment of Cadmium(II) and
Zinc(II) with N 2 -Donor Linkages in Presence of b-Diketone
Ligand; Supported by Structural, Spectral, Theoretical and
Docking Studies. Inorg. Chim. Acta 2018, 482, 717–725. DOI: 10.
1016/j.ica.2018.07.014.
56. Burnett, M. N.; Johnson, C. K. Ortep-III, Report ORNL-6895;
Oak Ridge National Laboratory: Oak Ridge, TN, 1996.
57. Bergerhof, G.; Berndt, M.; Brandenburg, K. Evaluation of
Crystallographic Data with the Program DIAMOND. J. Res.
Natl. Stand. Technol. 1996, 101, 221–225.
58. Hakimi, M.; Mardani, Z.; Moeini, K.; Schuh, E.; Mohr, F.
Complexation to Cadmium(II) of
a Tetradentate Ligand
Resulting from the Condensation of 2-Pyridinecarbaldehyde with
N-(2-Aminoethyl)Propane-1,3-Diamine. ZNB 2013, 68, 267–271.
DOI: 10.5560/znb.2013-2294.
59. Marandi, F.; Moeini, K.; Rudbari Hadi, A. Sonochemical
Synthesis and Characterization of Three Nano Zinc(II)
Coordination Polymers; Precursors for Preparation of Zinc(II)
Oxide Nanoparticles. ZNB 2016, 71b, 959–965.
60. Nakamoto, K. Infrared and Raman Spectra of Inorganic and
Coordination Compounds, 6th ed.; John Wiley: Hoboken, 2009; p
232.
61. Hakimi, M.; Moeini, K.; Mardani, Z.; Khorrami, F. Crystal
Structure and Characterization of a New Eight Coordinated
Cadmium Complex. J. Korean Chem. Soc. 2013, 57, 352–356.
DOI: 10.5012/jkcs.2013.57.3.352.
42. Mardani, Z.; Kazemshoar-Duzduzani, R.; Moeini, K.; Hajabbas-
Farshchi, A.; Carpenter-Warren, C.; Slawin, A. M. Z.; Woollins,
J. D. Anticancer Activities of a b-Amino Alcohol Ligand and
Nanoparticles of Its Copper(ii) and Zinc(ii) Complexes
Evaluated by Experimental and Theoretical Methods. RSC Adv.
2018, 8, 28810–28824. DOI: 10.1039/C8RA04578J.

10
M. HAKIMI ET AL.
62. Allen, F. H. The Cambridge Structural Database: A Quarter of a 69. Baldeau, S. M.; Slinn, C. H.; Krebs, B.; Rompel, A. Rompel, A.
Million Crystal Structures and Rising. Acta Crystallogr. 2002,
B58, 380–388.
Five Manganese(II) Complexes with Seven- or Eight-
Coordinated Mn(II), Revealing Different Coordination Modes
for the Nitrato Ligands. Inorg. Chim. Acta 2004, 357, 3295–3303.
DOI: 10.1016/j.ica.2004.03.021.
€
63. Ratilainen, J.; Airola, K.; Frohlich, R.; Nieger, M.; Rissanen, K.
Synthesis of a Tetradentate Piperazine Ligand and a Structural
Study of Its Coordination Compounds. Polyhedron 1999, 18,
2265–2273. DOI: 10.1016/S0277-5387(99)00117-5.
70. Desiraju, G. R.; Steiner, T. The Weak Hydrogen Bond: In
Structural Chemistry and Biology; Oxford University Press:
Oxford, 2001.
64. Qiang, Z.; Zhi, S.; Hao, Y.; Hui-Zhen, S. Coordination Modes of
Polypyridyl Quinoxaline with Hg(II), Pb(II), Co(II) and Mn(II).
Chinese J. Struct. Chem. 2016, 35, 69–76.
65. Wang, S.; Westmoreland, T. D. Correlation of Relaxivity with
Coordination Number in Six-, Seven-, and Eight-Coordinate
Mn(II) Complexes of Pendant-Arm Cyclen Derivatives. Inorg.
Chem. 2009, 48, 719–727. DOI: 10.1021/ic8003068.
66. Louloudi, M.; Nastopoulos, V.; Gourbatsis, S.; Perlepes, S. P.;
Hadjiliadis, N. Eight-Coordination in Nitrato Manganese(II)
Complexes with Tetradentate di-Schiff Bases Derived from 2-
Pyridyl Ketones: Preparation, Characterization and Catalytic
Activity for Alkene Epoxidation. Inorg. Chem. Commun. 1999, 2,
479–483. DOI: 10.1016/S1387-7003(99)00127-6.
67. Hwang, I. C.; Ha, K. Diacetato[N,N’-Bis-(2-Pyridylmethyl-
Idene)Cyclo-Hexane-1,2-Diamine]Manganese(II) Hexa-Hydrate.
Acta Crystallogr. 2008, E64, m453.
71. Hakimi, M.; Mardani, Z.; Moeini, K.; Mohr, F.; Fernandes, M. A.
Palladium, Cadmium and Mercury Complexes of 2-((2-((2-
Hydroxyethyl)Amino)Ethyl)Amino)Cyclohexanol:
Synthesis,
Structural, Spectral and Solution Studies. Polyhedron 2014, 67,
27–35. DOI: 10.1016/j.poly.2013.08.065.
72. Hakimi, M.; Moeini, K.; Mardani, Z.; Mohr, F. Microwave-
Assisted Template Synthesis of Diazacyclam-Based Macrocyclic
Copper Complex and Forming Octahedral, Square Planar and
Square Pyramidal Geometries by Ion Exchanging and
Introducing
a
Novel 2D Square-Grid Copper–Mercury
Coordination Polymer. Polyhedron 2014, 70, 92–100. DOI: 10.
1016/j.poly.2013.12.033.
73. Marandi, F.; Moeini, K.; Arkak, A.; Mardani, Z.; Krautscheid, H.
Docking Studies to Evaluate the Biological Activities of the Co(II)
and Ni(II) Complexes Containing the Triazine Unit: Supported by
Structural, Spectral, and Theoretical Studies. J. Coord. Chem.
2018, 71, 3893–3911. DOI: 10.1080/00958972.2018.1543871.
68. Mikuriya, M.; Hatano, Y.; Asato, E. Variable Coordination
Geometries in Manganese(II): Eight-, Seven-, and Six-
Coordinate Mn(II) Complexes with Pyridyl-Containing Schiff-
Base Ligands. Chem. Lett. 1996, 25, 849–850. DOI: 10.1246/cl.
1996.849.
74. Webpage,
https://www.drugs.com/mtm/doxorubicin.html
(accessed July 19, 2018).