Copper(II) and cadmium(II) complexes of mono-condensed N,O- or N,N,O-Donor ligands: synthesis, crystal structures, and antibacterial activity

Article abstract of DOI:10.1080/24701556.2021.1917611

Three new copper(II) and cadmium(II) complexes, [Cu(L¹)₂] (1), [CuL ² (N₃)] (2), and [Cd(L³)₂] (3), where L¹ = 2-bromo-4-chloro-6-cyclohexylaminomethylphenolate, L² =

Full text of DOI:10.1080/24701556.2021.1917611

Inorganic and Nano-Metal Chemistry
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Copper(II) and cadmium(II) complexes of mono-
condensed N,O- or N,N,O-Donor ligands: synthesis,
crystal structures, and antibacterial activity
Heng-Yu Qian
To cite this article: Heng-Yu Qian (2021): Copper(II) and cadmium(II) complexes of mono-
condensed N,O- or N,N,O-Donor ligands: synthesis, crystal structures, and antibacterial activity,
Inorganic and Nano-Metal Chemistry, DOI: 10.1080/24701556.2021.1917611
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INORGANIC AND NANO-METAL CHEMISTRY
https://doi.org/10.1080/24701556.2021.1917611
Copper(II) and cadmium(II) complexes of mono-condensed N,O- or N,N,O-Donor
ligands: synthesis, crystal structures, and antibacterial activity
Heng-Yu Qian
Key Laboratory of Surface & Interface Science of Henan, School of Material & Chemical Engineering, Zhengzhou University of Light Industry,
Zhengzhou, P.R. China
ABSTRACT
ARTICLE HISTORY
Three new copper(II) and cadmium(II) complexes, [Cu(L1)2] (1), [CuL2(N3)] (2), and [Cd(L3)2] (3),
where L1 ¼ 2-bromo-4-chloro-6-cyclohexylaminomethylphenolate, L2 ¼ 2-bromo-4-chloro-6-[(2-
morpholin-4-ylethylimino)methyl]phenolate, and L3 ¼ 2-bromo-4-chloro-6-[(3-morpholin-4-ylpropy-
limino)methyl]phenolate, have been prepared and structurally characterized by X-ray crystallog-
raphy. The Cu atom in complex 1 is in tetrahedrally distorted square planar geometry. The Cu
atom in complex 2 is in square planar geometry. The Cd atom in complex 3 is in octahedral
geometry. The complexes exhibited effective activities against B. subtilis, S. aureus, and E. coli.
Received 10 October 2018
Accepted 4 April 2021
KEYWORDS
Schiff base; reduced Schiff
base; copper complex;
cadmium complex; crystal
structure; antibacter-
ial activity
Introduction
purification. Other solvents and reagents were made in
China and used as received. C, H and N elemental analyses
were performed with a Perkin-Elmer 240 elemental analyzer.
Infrared spectra were recorded on a Nicolet AVATAR 360
spectrometer as KBr pellets in the 4000–400 cmꢀ1 region.
Schiff bases represent an important class of compounds in
medicinal chemistry with great potential for antibacterial
and anticancer applications.[1–3] Metal complexes derived
from various Schiff bases and reduced Schiff bases have
received much attention in coordination chemistry and bioi-
norganic chemistry.[4–6] Copper is a human essential elem-
ent, which has attracted wide interest to explore its
complexes with the aim for medical applications, due to its
important biological effects.[7,8] A great deal of copper(II)
complexes with Schiff bases are reported to possess signifi-
cant antibacterial activities.[9,10] In addition, cadmium(II)
complexes also show interesting biological activities includ-
ing antibacterial applications.[11,12] In the present work, two
new copper(II) complexes, [Cu(L1)2] (1) and [CuL2(N3)] (2),
and a new cadmium(II) complex, [Cd(L3)2] (3), where L1 ¼
UV-Vis spectra were recorded on
spectrometer.
a
Lambda 900
Synthesis of complex 1
3-Bromo-5-chlorosalicylaldehyde (1.0 mmol, 235 mg) and
cyclohexylamine (1.0 mmol, 99.2 mg) were dissolved in etha-
nol (30 mL). The mixture was stirred at room temperature
for 30 min to give a yellow solution. Then, solid NaBH4
(1.5 mmol, 56.6 mg) was slowly added to the solution under
ice-water bath. The mixture was reacted until the solution
changed to colorless. Then, Cu(ClO4)2ꢁ6H2O (1.0 mmol,
371 mg) was added to the above solution. The mixture was
further stirred at room temperature for 30 min to give blue
solution. After keeping the solution in air for a few days,
blue block-shaped single crystals, suitable for X-ray crystal
structure determination, were obtained. The crystals were
isolated by filtration and dried in a vacuum desiccator con-
taining anhydrous CaCl2. The yield was 32%. IR data (KBr;
ꢀmax, cmꢀ1): 3267, 3053, 3025, 2922, 2871, 1595, 1463, 986,
755. UV-Vis data in acetonitrile (k, nm (e, Mꢀ1 cmꢀ1)]: 235
(18,120), 385 (5,050), 670 (180). Anal. Calcd. for
C26H32Br2Cl2CuN2O2 (%): C, 44.69; H, 4.62; N, 4.01. Found
2-bromo-4-chloro-6-cyclohexylaminomethylphenolate, L2
¼
2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]-
phenolate, and L3 ¼ 2-bromo-4-chloro-6-[(3-morpholin-4-
ylpropylimino)methyl]phenolate (Scheme 1), were synthe-
sized and characterized by IR, UV-Vis, elemental analysis,
and single crystal X-ray diffraction analysis. The antibacter-
ial activities of the complexes were also studied.
Experimental
Materials and measurements
3-Bromo-5-chlorosalicylaldehyde, cyclohexylamine, 2-mor-
pholin-4-ylethylamine, and 3-morpholin-4-ylpropylamine
were purchased from Aldrich and used without further (%): C, 44.53; H, 4.71; N, 3.92.
CONTACT Heng-Yu Qian
hengyu_qian@126.com
Key Laboratory of Surface & Interface Science of Henan, School of Material & Chemical Engineering,
Zhengzhou University of Light Industry, Zhengzhou, 450002 P.R. China.
ß 2021 Taylor & Francis Group, LLC

2
H.-Y. QIAN
Scheme 1. The ligands.
Synthesis of complex 2
absorption corrections were performed using SADABS.[14]
Structures of the complexes were solved by direct methods
and refined against F2 by full-matrix least-squares methods
using SHELXTL.[15] All of the non-hydrogen atoms were
refined anisotropically. Hydrogen atoms in the complexes
were placed in idealized positions and constrained to ride
on their parent atoms. Crystallographic data for the com-
plexes are summarized in Table 1. Selected bond lengths
and angles are given in Table 2.
3-Bromo-5-chlorosalicylaldehyde (1.0 mmol, 235 mg) and 2-
morpholin-4-ylethylamine (1.0 mmol, 130 mg) were dis-
solved in ethanol (30 mL). The mixture was stirred at room
temperature for 30 min to give a yellow solution. To the
solution was added with stirring an ethanolic solution
(10 mL) of Cu(ClO4)2ꢁ6H2O (1.0 mmol, 371 mg) and NaN3
(1.0 mmol, 65 mg). The mixture was further stirred at room
temperature for 30 min to give blue solution. After keeping
the solution in air for a few days, blue block-shaped single
crystals, suitable for X-ray crystal structure determination,
were obtained. The crystals were isolated by filtration and
dried in a vacuum desiccator containing anhydrous CaCl2.
The yield was 46%. IR data (KBr; ꢀmax, cmꢀ1): 2056, 1635,
1442, 1161, 1076, 948, 858, 745. UV-Vis data in acetonitrile
(k, nm (e, Mꢀ1 cmꢀ1)]: 275 (20,150), 300 (11,272), 385
(9,370), 665 (210). Anal. Calcd. for C13H15BrClCuN5O2 (%):
C, 34.53; H, 3.34; N, 15.49. Found (%): C, 34.65; H, 3.41;
N, 15.32.
Antibacterial assay
The antibacterial activity of the complexes was tested against
B. subtilis, S. aureus, E. coli, and P. aeruginosa using LB
medium (Luria-Bertani medium: Tryptone 10 g, Yeast
extract 5 g, NaCl 10 g, distilled water 1000 mL, pH 7.4). The
IC50 (half inhibitory concentration) of the test compounds
were determined by a colorimetric method using the dye
MTT (3-(4,5-di-methylth-iazol-2-yl)-2,5-diphenyl tetrazo-
lium bromide).
Synthesis of complex 3
A stock solution of the synthesized compound (1000 lg
mLꢀ1) in DMSO was prepared and graded quantities of the
3-Bromo-5-chlorosalicylaldehyde (1.0 mmol, 235 mg) and 3-
morpholin-4-ylpropylamine (1.0 mmol, 144 mg) were dis- test compounds were incorporated in specified quantity of
solved in ethanol (30 mL). The mixture was stirred at room
temperature for 30 min to give a yellow solution. To the
solution was added with stirring an ethanolic solution
(10 mL) of Cd(CH3COO)2ꢁ2H2O (1.0 mmol, 266 mg). The
mixture was further stirred at room temperature for 30 min
to give colorless solution. After keeping the solution in air
for a few days, colorless block-shaped single crystals, suitable
for X-ray crystal structure determination, were obtained.
The crystals were isolated by filtration and dried in a vac-
uum desiccator containing anhydrous CaCl2. The yield was
31%. IR data (KBr; ꢀmax, cmꢀ1): 1631, 1453, 1272, 1153,
1046, 987, 955, 837, 756, 643. UV-Vis data in acetonitrile (k,
nm (e, Mꢀ1 cmꢀ1)]: 275 (19,310), 298 (9,565), 360 (6,120).
Anal. Calcd. for C28H34Br2CdCl2N4O4 (%): C, 40.34; H,
4.11; N, 6.72. Found (%): C, 40.26; H, 4.03; N, 6.85.
sterilized liquid LB medium. Suspension of the microorgan-
ism was prepared and applied to 96-well assay plate with
serially diluted compounds to be tested. 10 lL of tested sam-
ples at pre-set concentrations were added to wells with
Penicillin as a positive reference and with the solvent control
(5% DMSO) in medium and incubated at 37 ꢂC for 24 h.
After 24 h exposure, 10 lL of PBS (phosphate buffered
saline 0.01 mol Lꢀ1, pH 7.4) containing 4 mg mLꢀ1 of MTT
was added to each well. After 4 h, the medium was replaced
by 150 lL DMSO to dissolve the complexes. The absorbance
at 492 nm of each well was measured with an ELISA plate
reader. The IC50 value was defined as the concentration at
which 50% of the bacterial strain could survive.
Results and discussion
X-ray crystallography
Chemistry
Diffraction intensities for the complexes were collected at
298(2) K using a Bruker D8 VENTURE PHOTON diffract-
ometer with MoKa radiation (k ¼ 0.71073 Å). The collected
The complexes were prepared by the reaction of the ligands
and metal salts in ethanol. Crystals of the complexes are sol-
data were reduced using SAINT,[13] and multi-scan uble in DMF, DMSO, methanol, ethanol, and acetonitrile.

INORGANIC AND NANO-METAL CHEMISTRY
3
Table 1. Crystallographic data and refinement parameters for the complexes.
Parameters
1
2
3
Molecular formula
Mr
C26H32Br2Cl2CuN2O2
698.80
C13H15BrClCuN5O2
452.20
C28H34Br2CdCl2N4O4
833.71
Crystal color, habit
Crystal size, mm3
Crystal system
Space group
a, Å
Blue, block
0.23 ꢃ 0.23 ꢃ 0.19
Monoclinic
P21/c
20.547(2)
12.356(2)
24.224(2)
90
105.475(2)
90
5927.0(12)
8
1.566
Blue, block
Colorless, block
0.30 ꢃ 0.28 ꢃ 0.27
Monoclinic
P21/n
9.6015(13)
15.8070(17)
20.1719(18)
90
90.013(2)
90
3061.5(6)
4
1.809
0.32 ꢃ 0.32 ꢃ 0.29
Orthorhombic
Pccn
9.4879(6)
37.327(2)
9.1166(9)
90
90
90
3228.7(4)
b, Å
c, Å
ꢂ
a,
ꢂ
b, ꢂ
V, Å3
c,
Z
8
qcalcd, g cm–3
1.861
4.009
l, mm–1
3.639
3.539
F(000)
2808
1800
1656
Number of unique data
Number of observed data (I > 2r(I))
Independent reflections
Parameters
34580
11009
5194
631
9221
2997
2133
208
12915
4924
2641
370
Restraints
0
0
0
R1, wR2 (I > 2r(I))
R1, wR2 (all data)
Goodness of fit on F2
Largest difference peak and hole, e Å–3
0.0539, 0.1039
0.1525, 0.1483
0.994
0.552 and ꢀ0.573
0.0511, 0.0955
0.0811, 0.1075
1.071
0.465 and ꢀ0.489
0.0390, 0.0885
0.0762, 0.0983
0.849
0.340 and ꢀ0.379
Table 2. Selected bond distances (Å) and angles (ꢂ) for the complexes.
1
Cu1-O1
Cu1-N1
O2-Cu1-O1
O1-Cu1-N1
O1-Cu1-N2
2
1.896(5)
2.016(6)
158.50(19)
94.8(2)
Cu1-O2
Cu1-N2
O2-Cu1-N1
O2-Cu1-N2
N1-Cu1-N2
1.890(4)
2.032(5)
83.9(2)
93.2(2)
166.1(2)
92.8(2)
Cu1-O1
Cu1-N2
O1-Cu1-N1
N1-Cu1-N3
N1-Cu1-N2
3
1.885(3)
2.083(4)
93.22(16)
169.3(2)
84.46(17)
Cu1-N1
Cu1-N3
O1-Cu1-N3
O1-Cu1-N2
N3-Cu1-N2
1.925(4)
1.950(5)
93.05(17)
170.23(16)
90.75(18)
Cd1-O1
2.213(5)
Cd1-O3
2.203(5)
Cd1-N1
2.228(5)
Cd1-N2
2.589(5)
Cd1-N3
2.263(5)
Cd1-N4
2.602(5)
O3-Cd1-O1
O1-Cd1-N1
O1-Cd1-N3
O3-Cd1-N2
N1-Cd1-N2
O3-Cd1-N4
N1-Cd1-N4
N2-Cd1-N4
173.08(14)
81.41(18)
93.16(18)
84.15(17)
78.43(17)
95.15(18)
99.36(18)
177.39(16)
O3-Cd1-N1
O3-Cd1-N3
N1-Cd1-N3
O1-Cd1-N2
N3-Cd1-N2
O1-Cd1-N4
N3-Cd1-N4
105.05(19)
80.43(18)
174.4(2)
94.90(17)
103.56(17)
86.10(18)
78.77(17)
Figure 1. Molecular structure of complex 1, showing the atom-numbering
scheme. Displacement ellipsoids are drawn at the 30% probability level.
perpendicular angles, and from 158.5(2)ꢂ to 172.3(2)ꢂ for
the diagonal angles. The dihedral angle between the planes
defined by Cu1-O1-N1 and Cu1-O2-N2 is 24.1(5)ꢂ, and that
defined by Cu2-O3-N3 and Cu2-O4-N4 is 15.2(5)ꢂ. In the
crystal structure of the compound, molecules are linked
through N–HꢁꢁꢁO hydrogen bonds [N3–H3 ¼ 0.90 Å,
Structure description of compound 1
Molecular structure of compound 1 is shown in Figure 1.
The asymmetric unit of the compound contains two mono-
nuclear copper(II) complexes. The Cu atom in the com-
pound is coordinated by two amino nitrogen atoms and two
phenolato oxygen atoms from two L1 ligands, forming a tet-
rahedrally distorted square planar geometry. The Cu1 and
Cu2 atoms deviate from the least-squares planes defined by
the corresponding donor atoms by 0.061(3) and 0.046(3) Å,
respectively. The coordinate bond lengths in the complex
are similar to those observed in copper complexes with
reduced Schiff base ligands.[16,17] The distortion of the
square planar coordination can be observed from the coord-
H3ꢁꢁꢁO1 ¼ 2.53(2)
Å,
N3ꢁꢁꢁO1 ¼ 3.3154(5)
Å,
N3–H3ꢁꢁꢁO1 ¼ 146(3)ꢂ; N2–H2 ¼ 0.90 Å, H2ꢁꢁꢁO4 ¼ 2.50(2)
Å, N2ꢁꢁꢁO4 ¼ 3.1879(5) Å, N2–H2ꢁꢁꢁO4 ¼ 134(3)ꢂ], to form
dimers (Figure 2).
Structure description of compound 2
Molecular structure of compound 2 is shown in Figure 3.
The Cu atom in the complex is coordinated by the pheno-
late oxygen atom, imino nitrogen atom, and amino nitrogen
inate bond angles, ranging from 83.9(2)ꢂ to 94.8(2)ꢂ for the atom of the L1 ligand, and one azido nitrogen atom,

4
H.-Y. QIAN
Figure 2. Crystal packing structure of complex 1, viewed along the b axis. Hydrogen bonds are shown as dashed lines.
geometry, with the two phenolate oxygen atoms and two
imino nitrogen atoms from two L3 ligands defining the
equatorial plane, and with the two amino nitrogen atoms
from two L3 ligands occupying the axial positions. The Cd
atom deviates from the least-squares plane defined by the
equatorial donor atoms by 0.012(2) Å. The coordinate bond
lengths in the complex are similar to those observed in
Schiff base cadmium(II) complexes.[20,21] The distortion of
the octahedral coordination can be observed from the
coordinate bond angles, ranging from 78.4(2)ꢂ to 105.0(2)ꢂ
for the perpendicular angles, and from 173.1(2)ꢂ to
177.4(2)ꢂ for the diagonal angles.
Figure 3. Molecular structure of complex 2, showing the atom-numbering
scheme. Displacement ellipsoids are drawn at the 30% probability level.
IR and UV-Vis spectra of the complexes
The ꢀ(C ¼ N) absorptions are observed at 1635 cmꢀ1 for
complex 2 and 1631 cmꢀ1 for complex 2.[22] The typical
band indicative of the azide ligand in complex 2 is observed
forming a square planar geometry. The Cu atom deviates from
the least-squares plane defined by the donor atoms by 0.003(3) Å.
The coordinate bond lengths in the complex are similar to those
observed in Schiff base copper(II) complexes with azido lig-
and.[18,19] The distortion of the square planar coordination can be
observed from the coordinate bond angles, ranging from 84.5(2)ꢂ
to 93.2(2)ꢂ for the perpendicular angles, and from 169.3(2)ꢂ to
170.2(2)ꢂ for the diagonal angles. In the crystal structure of the
complex, molecules are linked through C–HꢁꢁꢁO, C–HꢁꢁꢁN and
C–HꢁꢁꢁCl hydrogen bonds [C4–H4 ¼ 0.93 Å, H4ꢁꢁꢁCl1i ¼ 2.72(5)
Å, C4ꢁꢁꢁCl1i ¼ 3.586(5) Å, C4–H4ꢁꢁꢁCl1i ¼ 156(5)ꢂ; C10–H10A
¼ 0.97 Å, H10AꢁꢁꢁO2ii ¼ 2.55(3) Å, C10ꢁꢁꢁO2ii ¼ 3.283(3) Å,
at 2056 cmꢀ1 [23] The weak absorption at 3267 cmꢀ1 can be
.
assigned to the vibration of the N–H groups of complex 1.
The weak peaks in the low wave numbers in the region
450–750 cmꢀ1 may be attributed to M–O and M–N bonds
in the complexes.
The UV-Vis spectra of the complexes were recorded in
10ꢀ5 mol Lꢀ1 in acetonitrile, in the range 200–800 nm. The
bands in the range of wavelength 350–400 nm arise mainly
due to the nitrogen to metal charge transfer transition
(LMCT).[24] The bands at about 300 nm in the spectra of com-
plexes 2 and 3 are attributed to the azomethine chromophore
C10–H10AꢁꢁꢁO2ii
¼
133(4)ꢂ; C10–H10B
Å,
¼
0.97 Å,
Å,
H10BꢁꢁꢁN3 ¼ 2.47(3)
C10ꢁꢁꢁN3 ¼ 3.061(3)
ꢄ
p-p transition. The bands at higher energies (235–275 nm)
are associated with the benzene p-p transition.
C10–H10BꢁꢁꢁN3 ¼ 119(4)ꢂ; symmetry codes: i: 1/2þx,-y,-1/2-z; ii:
x. 1/2-y, ꢀ1/2þz], to form a network (Figure 4).
[25]
ꢄ
Antibacterial activities
Structure description of compound 3
The complexes were screened for antibacterial activities
Molecular structure of compound 3 is shown in Figure 5.
against two Gram-positive bacterial strains (B. subtilis and S.
The Cd atom in the complex is coordinated in an octahedral aureus) and two Gram-negative bacterial strains (E. coli and

INORGANIC AND NANO-METAL CHEMISTRY
5
Figure 4. Crystal packing structure of complex 2, viewed along the c axis. Hydrogen bonds are shown as dashed lines.
References
1. Amim, R. S.; Pessoa, C.; Lourenco, M. C. S.; de Souza, M. V. N.;
Lessa, J. A. Synthesis, Antitubercular and Anticancer Activities
of p-Nitrophenylethyl-Enediamine-Derived Schiff Bases. MC.
2017, 13, 391–397. DOI: 10.2174/1573406412666161104123149.
2. Ariyaeifar, M.; Rudbari, H. A.; Sahihi, M.; Kazemi, Z.; Kajani,
A. A.; Zali-Boeini, H.; Kordestani, N.; Bruno, G.; Gharaghani, S.
Chiral Halogenated Schiff Base Compounds: Green Synthesis,
Anticancer Activity and DNA-Binding Study. J. Mol. Struct.
2018, 1161, 497–511. DOI: 10.1016/j.molstruc.2018.02.042.
3. Nigam, N.; Kumar, S.; Dutta, P. K.; Pei, S.; Ghosh, T. Chitosan
Containing Azo-Based Schiff Bases: Thermal, Antibacterial and
Birefringence Properties for Bio-Optical Devices. RSC Adv. 2016,
6, 5575–5581. DOI: 10.1039/C5RA27210F.
4. Malik, M. A.; Dar, O. A.; Gull, P.; Wani, M. Y.; Hashmi, A. A.
Heterocyclic Schiff Base Transition Metal Complexes in
Antimicrobial and Anticancer Chemotherapy. Med. Chem.
Commun. 2018, 9, 409–436. DOI: 10.1039/C7MD00526A.
5. Devi, J.; Devi, S.; Kumar, A. Synthesis, Antibacterial Evaluation
and QSAR Analysis of Schiff Base Complexes Derived from
[2,2’-(Ethylenedioxy)Bis(Ethylamine)] and Aromatic Aldehydes.
Med. Chem. Commun. 2016, 7, 932–947. DOI: 10.1039/
C5MD00554J.
Figure 5. Molecular structure of complex 3, showing the atom-numbering
scheme. Displacement ellipsoids are drawn at the 30% probability level.
Table 3. Antibacterial results (IC50, lg mLꢀ1).
Gram-positive
Gram-negative
P. aeruginosa
Compound
B. subtilis
S. aureus
E. coli
1
2
3
3.31
4.56
8.87
2.35
0.38
2.05
5.73
0.75
12.20
21.54
17.18
17.51
>50
>50
32.37
17.49
6. Galini, M.; Salehi, M.; Kubicki, M.; Amiri, A.; Khaleghian, A.
Structural Characterization and Electrochemical Studies of
Co(II), Zn(II), Ni(II) and Cu(II) Schiff Base Complexes Derived
Penicillin G
from
2-((E)-(2-Methoxyphenylimino)Methyl)-4-Bromophenol;
P. aeruginosa) by MTT method. The IC50 values of the com-
plexes against the bacteria are presented in Table 3. Penicillin
G was tested as a reference drug. Complexes 1 and 2 exhibited
effective activities against B. subtilis, S. aureus, medium activ-
ity against E. coli, and no activity against P. aeruginosa.
Complex 3 exhibited effective activity against S. aureus,
medium activities against B. subtilis and E. coli, and weak
activity against P. aeruginosa. It is interesting that complex 1
has the most active activity against S. aureus, with IC50 value
of 0.38 lg mLꢀ1, which is stronger than Penicillin G.
Evaluation of Antioxidant and Antibacterial Properties. Inorg.
Chim. Acta 2017, 461, 167–173. DOI: 10.1016/j.ica.2017.02.001.
7. Zhao, F. Y.; Wang, W. F.; Lu, W.; Xu, L.; Yang, S. L.; Cai, X. M.;
Zhou, M. Y.; Lei, M.; Ma, M. T.; Xu, H. J.; Cao, F. L. High
Anticancer Potency on Tumor Cells of Dehydroabietylamine
Schiff-Base Derivatives and a Copper(II) Complex. Eur. J. Med.
Chem. 2018, 146, 451–459. DOI: 10.1016/j.ejmech.2018.01.041.
8. Jana, K.; Maity, T.; Mahapatra, T. S.; das Mohapatra, P. K.;
Debnath, S. C.; Das, S.; Hossain, M.; Samanta, B. C. A Square
Pyramidal Copper(II) Complex of
a Schiff Base Ligand:
Synthesis, Crystal Structure, Antibacterial and DNA Interaction
Studies. Transit. Met. Chem. 2017, 42, 69–78. DOI: 10.1007/
s11243-016-0108-6.
9. Salehi, M.; Ghasemi, F.; Kubicki, M.; Asadi, A.; Behzad, M.;
Ghasemi, M. H.; Gholizadeh, A. Synthesis, Characterization,
Structural Study and Antibacterial Activity of the Schiff Bases
Derived from Sulfanilamides and Related Copper(II) Complexes.
Disclosure statement
No potential conflict of interest was reported by the author(s).

6
H.-Y. QIAN
Inorg. Chim. Acta 2016, 453, 238–246. DOI: 10.1016/j.ica.2016.
07.028.
[(2-Morpholin-4-Ylethylimino)Methyl]Phenol with Antimicrobial
Activity. Synth. React. Inorg. Met.-Org. Nano-Met. Chem. 2014,
44, 1541–1544. DOI: 10.1080/15533174.2013.802340.
10. Keypour, H.; Mahmoudabadi, M.; Shooshtari, A.; Bayat, M.;
Ghassemzadeh, M.; Hosseinzadeh, L.; Mohsenzadeh, F.; Harms,
K. Synthesis and Characterization of Two New N4O2
Macroacyclic Schiff-Base Ligands Containing Piperazine Moiety
and Mononuclear Co(III) and Cu(II) Complexes, Spectral, X-Ray
Crystal Structural, Theoretical Studies, Cytotoxic and
Antibacterial Properties. Polyhedron 2017, 129, 189–198. DOI:
10.1016/j.poly.2017.03.035.
ꢀ
19. Naiya, S.; Biswas, C.; Drew, M. G. B.; Goꢀmez-Garcıa, C. J.;
Clemente-Juan, J. M.;.; Ghosh, A. ; A Unique Example of
Structural and Magnetic Diversity in Four Interconvertible
Copper(II)-Azide Complexes with the Same Schiff Base Ligand:
A Monomer, a Dimer, a Chain, and a Layer. Inorg. Chem. 2010,
49, 6616–6627. DOI: 10.1021/ic1005456.
20. Fang, H.-C.; Yi, X.-Y.; Gu, Z.-G.; Zhao, G.; Wen, Q.-Y.; Zhu, J.-
Q.; Xu, A.-W.; Cai, Y.-P. Construction of Low-Dimensional
Cadmium Compounds with N2O/N2S Donor Tridentate Schiff
Base Ligands. Cryst. Growth Des. 2009, 9, 3776–3788. DOI: 10.
1021/cg900515j.
21. Basak, S.; Sen, S.; Marschner, C.; Baumgartner, J.; Batten, S. R.;
Turner, D. R.; Mitra, S. Synthesis, Crystal Structures and
Fluorescence Properties of Two New di- and Polynuclear Cd(II)
Complexes with N2O Donor Set of a Tridentate Schiff Base
Ligand. Polyhedron 2008, 27, 1193–1200. DOI: 10.1016/j.poly.
2007.12.005.
22. Li, Y.-T.; Dong, J.-W.; Lu, Y.; Gu, Y.-T.; Shang, C.-N.; Liu, F.-Y.;
Xin, Y.; Jing, C.-L.; You, Z.-L. Syntheses, Crystal Structures and
Urease Inhibition of Two Manganese(III) Complexes with bis-
Schiff Bases. Chinese J. Inorg. Chem. 2018, 34, 1192–1198.
23. Jing, C.-L.; Wang, C.; Yan, K.; Zhao, K.; Sheng, G.; Qu, D.; Niu,
F.; Zhu, H.; You, Z. Synthesis, Structures and Urease Inhibitory
Activity of Cobalt(III) Complexes with Schiff Bases. Bioorg. Med.
Chem. 2016, 24, 270–276. DOI: 10.1016/j.bmc.2015.12.013.
24. Banerjee, I.; Marek, J.; Herchel, R.; Ali, M. Magnetic Coupling in
EE and EO Azido-Bridged Binuclear Copper Complexes:
Synthesis, Structure and Magnetic Studies. Polyhedron 2010, 29,
1201–1208. DOI: 10.1016/j.poly.2009.12.023.
ꢀ
11. Kołodziej, B.; Grech, E.; Schilf, W.; Kamienski, B.; Pazio, A.;
ꢀ
Wozniak, K. The NMR and X-Ray Study of L-Arginine Derived
Schiff Bases and Its Cadmium Complexes. J. Mol. Struct. 2014,
1063, 145–152. DOI: 10.1016/j.molstruc.2014.01.058.
12. Ispir, E.; Kurtoglu, M.; Toroglu, S. The d10 Metal Chelates
Derived from Schiff Base Ligands Having Silane: Synthesis,
Characterization, and Antimicrobial Studies of Cadmium(II) and
Zinc(II) Complexes. Synth. React. Inorg. Met.-Org. Nano-Met.
Chem. 2006, 36, 627–631.
13. SMART, Version 5. 624 and SAINT (Version 6.04); Programs
Using the Windows NT System; Bruker AXS Inc.: Madison (WI,
USA), 2001.
14. Sheldrick, G. M. SADABS, Program for Empirical Absorption
€
Correction of Area Detector; Gottingen (Germany): Univ. of
Go€ttingen, 1996.
15. Sheldrick, G. M. A History of Shelxtl. Acta Crystallogr. A. 2008,
64, 112–122. DOI: 10.1107/S0108767307043930.
16. Yang, C.-T.; Vetrichelvan, M.; Yang, X. D.; Moubaraki, B.;
Murray, K. S.; Vittal, J. J. Syntheses, Structural Properties and
Catecholase Activity of Copper(II) Complexes with Reduced
Schiff Base N-(2-Hydroxybenzyl)-Amino Acids. Dalton Trans.
2004, 1, 113–121. DOI: 10.1039/B310262A.
17. Zhang, G. Q.; Constable, E. C.; Housecroft, C. E.; Zampese, J. A.
Assembling Chiral Salan-Copper(II) Complexes into
a 2D-
25. Zhou, Y.-M.; Ye, X.-R.; Xin, F.-B.; Xin, X.-Q. Solid State Self-
Assembly Synthesis of Cobalt(II), Nickel(II), Copper(II) and
Zinc(II) Complexes with a bis-Schiff Base. Transition Met. Chem.
1999, 24, 118–120. DOI: 10.1023/A:1006989707001.
Network with Carboxylic Acid Functionalization. Inorg. Chem.
Commun. 2014, 43, 51–55. DOI: 10.1016/j.inoche.2014.02.009.
18. Xue, L. W.; Feng, Y. X.; Zhang, C. X. Synthesis and Structures of
Copper(II) and Nickel(II) Complexes Derived from 2-Methyl-6-