Synthesis, crystal structure, and antioxidant property of a new Co(III) coordination polymer based on ligand (E)-2-{2-[1-(1-methyl-1H-benzo[d]imidazol-2-yl)ethylidene]hydrazinyl}benzo[d]thiazole

Article abstract of DOI:10.1080/15533174.2013.841234

A new Co(III) complex, [CoL₂](ClO₄)(CH₃CN) (1) (HL = (E)-2-{2-[1-(1-methyl-1H-benzo[d]imidazol-2-yl)ethylidene]hydrazinyl}benzo[d]thizole), has been prepared by solvent evaporation method, and characterized by single-crystal X-ray diffraction, bond valence sum, and elemental analysis. The result of single-crystal X-ray diffraction analysis indicates that each Co(III) ion is six-coordinated by six nitrogen atoms from two L^- to form distorted octahedral geometry. The hydrogen bonds and π.π stacking interactions ensure the cohesion of crystal lattice in a 3D supramolecular framework in the solid state. The antioxidant activities of HL and 1 were also studied.

Full text of DOI:10.1080/15533174.2013.841234

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Synthesis, Crystal Structure, and Antioxidant Property
of a New Co(Ш) Coordination Polymer Based on
Ligand (E)-2-{2-[1-(1-methyl-1H-benzo[d]imidazol-2-
yl)ethylidene]hydrazinyl}benzo[d]thiazole
a
a
a
a
Wen-Ting Deng , Jia-Cheng Liu , Ping Cao & Ya-Qin Xu
a
Key Laboratory of Eco-Environment-Related Polymer Materials of Ministry of Education, Key
Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Bio Electrochemistry
&
Environmental Analysis of Gansu Province, College of Chemistry and Chemical
Engineering, Northwest Normal University, Lanzhou, P. R. China
Accepted author version posted online: 16 Sep 2013.Published online: 01 Dec 2014.
To cite this article: Wen-Ting Deng, Jia-Cheng Liu, Ping Cao & Ya-Qin Xu (2015) Synthesis, Crystal Structure, and
Antioxidant Property of a New Co(Ш) Coordination Polymer Based on Ligand (E)-2-{2-[1-(1-methyl-1H-benzo[d]imidazol-2-
yl)ethylidene]hydrazinyl}benzo[d]thiazole, Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry,
45:5, 667-672, DOI: 10.1080/15533174.2013.841234
To link to this article: http://dx.doi.org/10.1080/15533174.2013.841234
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Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry (2015) 45, 667–672
Copyright © Taylor & Francis Group, LLC
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2013.841234
Synthesis, Crystal Structure, and Antioxidant Property of a
New Co(S) Coordination Polymer Based on Ligand (E)-2-{2-
[
1-(1-methyl-1H-benzo[d]imidazol-2-yl)ethylidene]hydrazinyl}
benzo[d]thiazole
WEN-TING DENG, JIA-CHENG LIU, PING CAO and YA-QIN XU
Key Laboratory of Eco-Environment-Related Polymer Materials of Ministry of Education, Key Laboratory of Polymer Materials of
Gansu Province, Key Laboratory of Bio Electrochemistry & Environmental Analysis of Gansu Province, College of Chemistry and
Chemical Engineering, Northwest Normal University, Lanzhou, P. R. China
Received 17 July 2013; accepted 1 September 2013
A new Co(S) complex, [CoL ](ClO )(CH CN) (1) (HL D (E)-2-{2-[1-(1- methyl- 1H-benzo[d]imidazol-2-yl)ethylidene]hydrazinyl}
2
4
3
benzo[d]thizole), has been prepared by solvent evaporation method, and characterized by single-crystal X-ray diffraction, bond
valence sum, and elemental analysis. The result of single-crystal X-ray diffraction analysis indicates that each Co(S) ion is six-
¡
coordinated by six nitrogen atoms from two L to form distorted octahedral geometry. The hydrogen bonds and p. . .p stacking
interactions ensure the cohesion of crystal lattice in a 3D supramolecular framework in the solid state. The antioxidant activities of
HL and 1 were also studied.
Keywords: Co(III) complex, crystal structure, antioxidant activity
Introduction
coordination polymer containing thiazole group and its
biological property is still very limited. With this back-
Over the past several decades, the self-assembled coordi- ground information, we herein report a new Co(S) com-
nation polymers (CPs) have received considerable atten- plex, namely, [CoL ](ClO )(CH CN) (1), derived form
2
4
3
tion due to their interesting functions in catalysis, gas ligand (E)-2-{2-[1-(1-methyl-1H-benzo[d]imidazol-2-yl)eth-
storage, luminescence, chemical sensors, biological activ- ylidene]hydrazinyl}benzo[d]thizole (HL). The antioxidant
[
1–10]
ity, and so on.
In particular, with the increasing activities of HL and 1 were also described.
attention of people against oxidative and aging, CPs have
been extensive used in biological activity, especially for
the oxidative activity. There are several key factors to
influence biological activity of CPs, such as metal ions
and ligands. Among these factors, Co(S) ion shows sig- Experimental
[
11–13]
nificant effects on biological activity,
while thiazole
[
14]
derivatives exhibit perfect biological properties as well,
General Remarks
[
15]
which can also applied in medicine.
Up to now, the
All solvents and reagents were used directly without further
purification as commercially analytical grade. Elemental
analyses of C, H, and N were recorded on a VaRio EL
Instrument. X-ray diffraction analysis data of 1 was collected
reports of CPs based on thiazole Schiff base ligand have
[
16–18]
been prepared.
However, the study of Co(S)
with a Bruker SMART APEX II diffractometer with graph-
Address correspondence to Jia-Cheng Liu, Key Laboratory of
Eco-Environment-Related Polymer Materials of Ministry of
Education, Key Laboratory of Polymer Materials of Gansu
Province, Key Laboratory of Bio Electrochemistry & Environ-
mental Analysis of Gansu Province, College of Chemistry and
ꢀ
ite-monochromated Mo Ka radiation (λ D 0.71073 A) by u
scan mode. The structure was solved by direct methods with
SHELXS-97 and refined with the full-matrix least-squares
[
19]
technique using the SHELXL-97 program. All non-hydro-
Chemical Engineering, Northwest Normal University, Lanzhou gen atoms were refined anisotropically. All the hydrogen
30070, P. R. China. E-mail: jcliu8@nwnu.edu.cn
atoms were fixed geometrically at calculated distances and
Color versions of one or more of the figures in the article can be refined isotropically. The detailed crystallographic data and
found online at www.tandfonline.com/lsrt. structure refinement for 1 are given in Tables 1 and 2.
7

6
68
Deng et al.
ꢀ
ꢀ
Table 1. Crystal data and structure refinement of 1
Table 2. Selected bond lengths (A) and bond angles ( ) and
valence sum calculations of 1
Complex
1
Co1-N2 D 1.932(2)
N4-Co1-N11 D 101.60(9)
N6-Co1-N8 D 91.40(9)
N6-Co1-N9 D 100.57(9)
N6-Co1-N11 D 89.89(9)
N8-Co1-N9 D 82.07(9)
N8-Co1-N11 D 163.08(9)
N9-Co1-N11 D 81.12(9)
N4-Co1-N6 D 81.25(10)
N4-Co1-N8 D 95.27(9)
Identification code
Empirical formula
Formula weight
Temperature
950220
Co1-N4 D 1.898(2)
C H ClCoN O S
Co1-N6 D 1.930(2)
3
8
35
11
4 2
868.27
293(2)
Co1-N8 D 1.934(2)
Co1-N9 D 1.899(2)
Crystal system
Triclinic
Co1-N11 D 1.921(2)
N2-Co1-N4 D 81.86(9)
N2-Co1-N6 D 162.85(9)
N2-Co1-N8 D 93.13(9)
N2-Co1-N9 D 96.43(9)
N2-Co1-N11 D 90.56(9)
P-1
ꢀ
Space group
a D 9.8419(15) A
ꢀ
b D 14.343(2) A
ꢀ
c D 14.532(2) A
N4-Co1-N9 D 176.77(9)
P
ꢀ
Unit cell dimensions
a D 88. 88.361(2)
S(Co) D 2.89
ꢀ
ꢀ
b D 89.327(2)
g D 74.679(2)
ꢀ
3
Volume
Z
1977.6(5) A
2
1
Synthesis of L , L , and HL
2
¡
3
Density (calculated)
F(000)
1.458 Mg¢m
896
1
1
-(1-methyl-1H-benzo[d]imidazol-2-yl)ethanone (L ), 2-
Crystal size
Theta range for data collection
Limiting indices
0.24 £ 0.23 £ 0.21 mm
2
hydrazinyl-6-methylbenzo [d]thiazole (L ) and (E)-2-{2-[1-(1-
methyl-1H-benzo[d]imidazol-2-yl)ethylidene] hydrazinyl}
benzo[d]thizole (HL) were prepared according to published
ꢀ
2.26–28.04
¡11 ꢀ h ꢀ 11
¡
17 ꢀ k ꢀ 9
[20–23]
procedures.
The synthesized steps are given in
¡
17 ꢀ l ꢀ 17
Scheme 1.
Reflections collected / unique
6900 / 6034
R(int) D 0.0207]
6900 / 0 / 521
1.048
[
Data/restraints/parameters
Goodness of fit on F
2
Synthesis of 1
Final R indices [I > 2s(I)]
R indices (all data)
R D 0.0454
1
wR D 0.1286
2
HL (0.2 mmol, 0.065 g) was dissolved into a mixed solution
of 20 mL methanol and 10 mL acetonitrile. After stirring for
R D 0.0513
1
wR D 0.1359
2
0
.5 h, Co(ClO ) ¢6H O (0.2 mmol, 0.0724 g) was added in
4
2
2
¡
3
Largest diff. peak and hole
0.591 and –0.312 e¢A
the solution. The mixture was further stirred for another
.5 h and then filtered at ambient temperature. After one
0
month, purple block-shaped crystals of 1 suitable for X-ray
diffraction were obtained. Yield, 32%. Elemental Anal.
Calcd. for C H CoClN O S : C, 52.56%; H, 4.06%; N,
3
8
35
11
4 2
17.74%; Found: C, 52.46%; H, 4.16%; N, 17.49%.
Sch. 1. The synthesized steps of HL.

A New Co(S) Coordination Polymer
669
Scavenger Measurements of Superoxide Radical and
Hydroxyl Radical
spectrophotometer was used to measure the absorbance at
520 nm (A , A , A ). The results are presented in and Figure
i
0
c
6
b. The suppression ratio was calculated by using following
The superoxide radicals were measured in the test system
[27]
equation
:
[24]
using VitB /NBT /MET. HL and 1 dissolved in DMF (Ci
2
D 0.2, 1.0, 2.0, 3.0, 4.0 mM), respectively, were add to
(
1–5)
¡
5
¡1
Suppression ratio.%/ D [.A ¡ A0/=.Ac ¡ A0/] £ 100%:
solution containing NBT (4.6 £ 10
mol¢L ), MET
i
¡
1
¡6
¡1
(
0.01 mol¢L ), VitB (3.3 £ 10 mol¢L ), and phosphate
2
¡
1
buffer (0.067 mol¢L ). After incubating the mixture solution
Where, A is the absorbance in the presence of HL and 1;
i
ꢀ
at 30 C for 10 min and illuminating with a fluorescent lamp A is the absorbance in the absence of HL and 1; and Ac is
0
for 3 min, the absorbance (A ) of these samples were mea- the absorbance in the absence of HL and 1, EDTA-Fe(II)
i
sured at 560 nm. The results are shown in the following sec- and H O .
2
2
tion. The suppression ratio was calculated by using following
The antioxidant activity was described as the 50% inhibi-
[
25]
equation
:
tory concentration (IC ). IC values were calculated from
5
0
50
regression lines where: x was the concentration of HL and 1
in mM and y was the percent inhibition of HL and 1.
Suppression ratio.%/ D [.A0 ¡ A /=.A0/] £ 100%
i
Where, A is the absorbance in the presence of HL and 1,
i
Results and Discussion
and A is the absorbance in the absence of HL and 1.
0
The hydroxyl radical scavenging study was prepared
Structural Description of 1
[26]
through Fenton reaction.
HL and 1 were dissolved in
DMF (Ci(1–5) D 2.0, 4.0, 6.0, 8.0, 10.0 mM). Then, 1 mL Perspective view of complex 1 together with atom numbering
9
45 mM EDTA-Fe(II), 0.5 mL 114 mM safranine, 1 mL 3% scheme is shown in Figure 1. In this structure, the Co-N
ꢀ
H O , and 2.5 mL 0.15 M phosphate buffer (pH D 7.4) were bond lengths in the range of 1.898–1.934 A give a basic evi-
2
2
[
28]
added to the 30 mL previously tested solution. The sample dence for 1 being a Co(III) complex,
which is also con-
[
29–31]
without the tested compounds was used as the control. The firmed by the result of bond valence sum (BVS) analysis
ꢀ
resulting mixture was incubated for 1 h at 37 C. Then UV (shown in Table 2). The asymmetric unit of 1 contains one
¡
Fig. 1. Crystal structure of 1 with 30% thermal ellipsoids probability. All hydrogen atoms, free acetonitrile molecule, and free ClO4
ion are ignored for clarity.

6
70
Deng et al.
Fig. 2. The hydrogen-bonds (C-H. . .O and C-H. . .N) in 1.
ꢀ
¡
crystallographically unique Co(III) cation, two L , one free (thiazoyl) [1.921(2) and 1.930(2) A], which can be ascribed to
perchlorate ion, and one free acetonitrile molecule. Each Co the more electron-rich coordination site of the benzimidazoyl
¡
(
III) ion is coordinated by six nitrogen atoms of two L to group than the thiazoyl unit. Within one asymmetric unit,
form a distorted octahedral geometry. The degree of distor- two ligands are aligned nearly perpendicular to each other.
tion compared to an ideal octahedral geometry can be Finally, as shown in Figures 2 and 3, the asymmetric units
reflected by the bond angles around the central metal ion [CoL ](ClO )(CH CN) are connected by the hydrogen-bonds
2
4
3
ꢀ
ꢀ
from 81.25(10) to 176.77(9) (Table 2). It is interesting to (C-H. . .O and C-H. . .N, the detailed geometrical parameters
note that the distances of Co-N(benzimidazoyl) [1.932(2) and of hydrogen bonding shown in Table 3) and offset p. . .p
ꢀ
I
1
.934(2) A] exhibit slightly shorter than those of Co-N stacking: Cg-Cg (Cg D ligand plane, the centroid-centroid
Fig. 3. The offset p. . .p stacking in 1.

A New Co(S) Coordination Polymer
671
Table 3. The geometrical parameters of hydrogen bonding of 1
ꢀ
ꢀ
ꢀ
ꢀ
D-H. . .A
D-H (A)
H. . .A (A)
D. . .A (A)
D-H. . .A ( )
Symmetry code
C32C-H32C. . .O1B
C37-H37C. . .O1B
C19A-H19A. . .O3B
C10-H10. . .N1
0.93
0.96
0.93
0.96
2.56
2.58
2.60
2.47
3.39
3.29
3.29
3.39
149
131
132
160
A: x, y, 1 C z
B: 1 – x, 1 – y, 1 – z
C: 1C x, y, z
ꢀ
ꢀ
distance: 4.07 A, the dihedral angle: 0.00 , the interplanar also showed considerably good scavenging activity with 49%
ꢀ
I
distance: 3.70 A, symmetry code: : 1 – x, –y, 1 – z), to gener- and 63% at concentration of 10 mM. Especially, 1 show bet-
ate a 3D supramolecular network in the solid state.
ter antioxidants than those of HL. It was believed that the
information of this work would afford a new possible for
potential antioxidants and therapy some diseases.
Antioxidant Activity of HL and 1
Figure 4 displays and compares the inhibitory effects of HL
¡
Conclusion
and 1 based on O _ (Figure 4a) and _OH (Figure 4b). It can
2
¡
be seen that increasing inhibitory effects against O _ and_OH
2
In summary, a new Co(S) complex, [CoL ](ClO )(CH CN),
2
4
3
are shown with the increasing concentration of the tested
compounds, while the suppression ratio increases with the
increasing sample concentration in the region of tested con-
centration. As shown in Figure 4(a), IC value of the inhibi-
has been synthesized under solvent evaporation method
based on the schiff base ligand (E)-2-{2-[1-(1-methyl-1H-
benzo[d]imidazol-2-yl)ethylidene]hydrazinyl}benzo[d]thizole
(HL). The result of single-crystal X-ray diffraction analysis
reveals that 1 is a mononuclear complex. The hydrogen
bonds (C-H. . .O and C-H. . .N) and p. . .p interactions further
extend the mononuclear units into a 3D supramolecular
structure. In addition, the antioxidant activities of HL and 1
were also studied to afford a guiding role for potential antiox-
idant resistance.
5
0
¡
tory effects of HL and 1 against O _ are 3.98 and 1.46 mM,
2
respectively, which obviously display higher superoxide dis-
mutase activities than that of standard antioxidants, such as
[32]
vitamin C (IC : 852 mM). Among the studied HL and 1
5
0
show higher superoxide scavenging ability of 50% and 67%
at concentration of 4 mM. As illustrated in Figure 4b, the
observed IC50 values of the inhibitory effects of HL and 1
based on _O H are 10.12 and 5.58 mM, respectively. HL and 1
Funding
(a)
The authors are thankful for support of this study by the
National Natural Science Foundation of China
6
4
2
0
0
0
(No.20871099) and Gansu provincial Natural Science Foun-
dation of China (No. 0710RJZA113).
1
HL
Supplementary Material
CCDC 950220 contains the supplementary crystallographic
data for complex 1. The specific information may be obtained
free of charge from the director, CCDC, 12 Union Road,
Cambridge, CB21EZ, UK (fax: C44-1223-336033; e-mail:
deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
1
2
3
4
Concentration(µM)
(
b)
6
4
2
0
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1