A novel 4-(1H-benzimidazol-2-yl)-2-methoxy-phenol derived fluorescent sensor for determination of CN– ion

Article abstract of DOI:10.14233/ajchem.2017.20662

A novel fluorescent sensor 4-(1H-benzimidazol-2-yl)-2-methoxy-phenol derivative was synthesized. Solution of 4-(1H-benzimidazol-2-yl)-2-methoxy-phenol (1 × 10^–7 M) in DMSO displays highly sensitives and rapid respons to CN^– ion [valu

Full text of DOI:10.14233/ajchem.2017.20662

Asian Journal of Chemistry; Vol. 29, No. 9 (2017), 1959-1962
ASIAN JOURNAL OF CHEMISTRY
https://doi.org/10.14233/ajchem.2017.20662
A Novel 4-(1H-Benzimidazol-2-yl)-2-methoxy-phenol Derived
–
Fluorescent Sensor for Determination of CN Ion
1
,2,*
2
2
R. RAHMAWATI , B. PURWONO and S. MATSJEH
1
Study Program of Chemistry, Department of Education of Mathematics and Natural Sciences, Universitas Mataram, Jalan Majapahit 62, Mataram,
Indonesia
2
Department of Chemistry, Universitas Gadjah Mada, Jalan Kaliurang Sekip Utara, Bulaksumur 21, Yogyakarta, Indonesia
*
Corresponding author: E-mail: mymine76@ymail.com
Received: 21 March 2017; Accepted: 15 June 2017;
Published online: 15 July 2017;
AJC-18473
A novel fluorescent sensor 4-(1H-benzimidazol-2-yl)-2-methoxy-phenol derivative was synthesized. Solution of 4-(1H-benzimidazol-2-
–
7
–
yl)-2-methoxy-phenol (1 × 10 M) in DMSO displays highly sensitives and rapid respons to CN ion [values of LOD = 1.8 × 10 M and
–6
6
–1
–
a
K = 2.5 (± 0.26) × 10 M ]. Sensor 4-(1H-benzimidazol-2-yl)-2-methoxy-phenol coordinated with CN ion form with a 1:1 binding
stoichiometry.
Keywords: Fluorescent sensor, Cyanide ion, Benzimidazole.
The investigation on synthesis of anion receptor have
attracted a number of chemists due to the key roles played by
anions during the chemicals, biological and environmental
prosesses [6]. Fluorescence sensation is an exceptional tech-
nique among the different detection methods used for recog-
nition of different anion, such as cyanide anion, because of its
high sensitivity [7]. Consequently, cyanide selective detection
and quantification are very important, which has been the
object of increasing investigation [8].
INTRODUCTION
Research on design and development of artificial mole-
cular sensor for recognition and sensing of anion is currently
attracting much interest because anion plays many fundamental
roles in chemical and biological process [1]. In recent year,
increasing attention in the field of host-guest chemistry has
been devoted to the fast development of anion recognition
system. The development of fluorescent and colorimetric
probes for anion is finely and an area of interest. Water soluble
anions (one of them is cyanide) play crucial roles in a range of
biological phenomenan and are implicated in many disease
states [2].
–
The synthesis of sensory compound to detect CN ion has
been largely reported. The sensory compound of fluorescence
–
for anion CN through the formulation of complex between
sensor and ion copper has been reported to have a high selectivity
3
–
5
–1
Cyanide is traditionally known as a poison and has been
used in mass homicides and suicides and as a weapon of war.
Sodium and potassium cyanide salts are widely used in many
industries like extracting prosess for the recovery of gold and
silver, electroplating, dyeing, printing and in the synthesis of
organic and inorganic chemicals (nitriles, amides, esters and
amines) as well as producting of chelating agents [3].
s
(LOD = 1.4 × 10 M, K = 3.3 × 10 M ), the improvement of
its fluorescence happened due to the presence of attractiveness
of copper-cyanide [9]. 4-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1-
allylpyridinium bromide (HPEAPB) compound is also used as
–
colorimetry sensor to detect CN ion, because this sensor has a
high selectivity and fast response with LOD value equals 3.4 ×
6
10 M [10]. A compound diluted in DMSO/HEPES buffer was
–
–
–
The cyanide anion (CN ) is known as one of the most
used to detect CN ion, the LOD of CN was measured through
UV-visible titration experiment, LOD value is 10.3 µM [11].
Benzimidazole and its derivatives have been studied in
anion and cation recognition system that display colour changes
or fluorescence quenching or enhancement upon binding. The
different substituents at the benzimidazole are intended to
improve the intramolecular electron delocalization and will
tune the photophysical properties of new sensors and optimize
rapidly acting and powerful poisons [4]. It is an extremely
toxic anion and can directly lead to the death of human beings
in several minutes. The cyanide ion also detrimentally
affects vascular, visual, central nervous, cardiac, endocrine and
metabolic functions. However, cyanide toxicity, large quantites
of cyanide salt are still widely used in industrial production
[
5].

1
960 Rahmawati et al.
Asian J. Chem.
of the recognition of target analytes through a greater sensitivity
of fluorescence [12]. Compound from benzimidazole group
has been largely reported in terms of its roles as antioxidant
groups (such as two –OH and –OMe groups) and two systems
of conjugations which strengthen the fluorescent properties.
Melting point was measured using a Electrothermal-9100,
the functional group were detected using a FTIR Shimadzu
Prestige-21, Mass spectra were taken by Gas Chromatograph-
[
benzimidazole moiety has been used as chemosensor of
13] and chemosensor. Azo dye compound featuring with
–
ratiometric and colorimetric to detect CN ion, this recognition
1
13
Mass Spectrometer (GCMS-QP2010S), H NMR and C NMR
were measured using a JOEL JNM ECA-500 MHz, fluorescent
were measured using a Spectro Fluorophotometer Shimadzu
RF-6000.
9
–1
produced Kbinding value = 9.54 × 10 M , the interactions of
sensory-ion occured with the ratio of stoichiometry 1:2 [14].
Other compound having benzimidazole group, that has
–
substituent of OH clusters, has also been used to detect CN
All the reagents for synthesis obtained commercially were
used without further purification, e.g., DMSO, aquadest,
ethanol. The material used in the synthesis are vanillin, o-
phenylendiamine, boric acid. The anion were added in the form
of sodium cyanide (NaCN salt). All materials for synthesis is
p.a. quality Merck.
ion in the protic/aqueous systems gives Kbinding value = 0.45 ×
3 –1
0 M [15]. Triphenylimidazole compound (contains ring of
1
benzimidazole) has also been used as colorometric and fluore-
–
scence sensor to detect CN anion with the LOD value = 0.11
–
6
×
10 M [16]. A compound bearing 2-(2’-hydroxyphenyl)
benzimidazole was investigated an a sensor for metal ions by
using UV-visible and spectroscopy method [17]. Benzimi-
dazole was using to designed a rapid “OFF-ON” fluorescent
sensor system based on the selective response of in situ formed
The method on this synthesis is adopted from Karimi-
Jaberi and Amiri method [6]. A vanillin (0.32 g), o-phenylen-
diamine (0.21 g) and boric acid (0.1 g), were diluted in 5 mL
hot water.A mixture was stirred at 40 °C for 5 min (the progress
of reaction was monitored by TLC). After completion of
reaction, the obtained solid was collected by filtration and
purified by recrystallization from boiling ethanol (Scheme-
I). Light yellow powder, 94 % yield (0.22 g), m.p 229-231
3+
–
2 4
L-Fe complexes toward H PO [18].
The traditional synthesis of benzamidazole involves
the reaction between o-phenylenediamine and carboxylic
acid or their derivatives in the presence of strong acid such as
polyphosphoric acid and presence of expensive catalysts
–1
°C; FTIR (KBr, νmax, cm ): 3387 OH & N-H, 2337.72 C=N,
2
1604.77 C=C aromatic (3062.96 C-H sp ), 2931 C-H methyl,
(
such as sulphur, FeCl , H
3
O
2 2
, HCl, CAN, NaN , CuCl, oxone,
3
1
1273.02 C-O-C); H NMR (500 MHz, CDCl
PhI(OAc) , BH and using alumina and zirconia) and precence
2
3
3
: 3.59 (m, 3H),
of organic solvent (such as DMSO, DMF, toluene and dioxane)
at elevated temperature [19-22].
5.437 (m, 1H), 6.372 (d, 1H), 6.642 (s, 1H), 6.692 (s, 1H),
7.24 (s, 2H), 7.51 (s, 1H), 7.664 (m, 1H), 9.004 (d, 1H), 9.586
13
In this work, the new fluorescence sensory compound
–
from benzimidazole as receptor to detect CN ion has been
(s, 1H); C NMR (500 MHz, CDCl
115.56, 118.54, 122.06, 127.89, 136.06, 142.6, 145.86, 147.7,
3
: 55.49, 110.69, 112.99,
+
148.22, 153.59). MS (EI): m/z 240 (M , 100 %), 137 (M , 80
+
synthesized. The advantages of this receptor is its simple struc-
ture. It has the substituent of OH clusters from its vanillin
skeletons used as a binding site that forms hydrogen bonds
+
+
%), 122 (M , 9 %), 65 (M , 7 %).
–
RESULTS AND DISCUSSION
with CN anion and has a high flourometric sensitivity to recog-
–
nize CN anion with a low detection limit value. The behaviour
1
The compound S was used to detect the cyanide ion. The
–
of this new compound towards CN anion was investigated by
–7
concentration of sensor used was 1 × 10 M and of anions
fluorescence spectroscopy in DMSO.
–6
used was 1 × 10 M. In term of colour indicator, there was not
any change, which means the colorimetry did not occur. In
the observation under 366 nm UV light, it showed that the
EXPERIMENTAL
The predominance of this synthesis is use of inexpensive
and sustainable catalyst, the use of non-organic solvents and
its short reaction time. The use of vanillin as a source of carbonyl
synthesis of benzimidzole derivatives have not been reported
previously.
compound S
1
is fluorescent in nature (Fig. 1).
–
The CN detection indicated activity of anions through
hydrogen bond formation that occurs in the side of –OH
binding site [23]. The selectivity of the host for a specific anion
of interest could be rationalized on the basis of not only the
guest basicity but also complementary shape between the host
and the anionic guest. In particular, multiple hydrogen-bonding
The synthesized compound has a character as a good
chemosensor compound because it contains two auxochrome
H
O
OCH3
C
H N
2
N
0
.1 g Boric acid
Stirred 40 °C
+
OH
H N
2
N
OCH3
Light brown
9
4 % Light yellow powder
H
OH
S1
White
Scheme-I: Synthesis of the sensor compound S
1

–
A Novel Fluorescent Sensor for Determination of CN Ion 1961
Vol. 29, No. 9 (2017)
For further understanding about the sensing property of
–
to CN , fluorescent titration experiment was conducted on
S
1
–
gradual increase the added CN concentrations towards the
changes of fluorescent intensity. The highest intensity occurred
in the addition of 50 µL of 50 equivalent ion. At concentrations
of 900 and 1000 equivalent ion indicated the highest intensity
–1
of 720812 (1000 eq. 1 × 10 M) [Fig. 3(a) and 3(c)].
The formation analysis of sensor-anion complex S
1
–
compounds by CN ion is derived from the the Job’s plot
(Fig. 4) [26]. The Job’s plot for compexation of sensor with
CN ion showed a maximum titration occured in mol fraction
–
–
[1 × 10 M] (a) and S
7
– –6
+ CN [5 × 10 M]
Fig. 1. Fluorescence view of S
1
1
ratio of 0.5 by fluorescence spectra. It showed one-to-one
–
with ion CN [11] and indicates the
(
b) in DMSO under UV lamp
binding between S
1
formation of receptor-anion complex with a stoichiometric
ratio of 1:1 [26].
interactions were necessary in high-affinity anion binding sites.
Consequently, it was reasonable that the compound S showed
a high selectivity for cyanide ion [24]. The proposed binding
The strength of the formation of sensor-analyte complex
can be expressed in the form of Kbinding. The value of Kbinding
obtained using quadratic non-linear calculations based on data
from fluorescent titration. Fig. 5 shows the plot between the
concentration of ions with fluorescent Intensity maximum and
the non-linier of calibration curve (insert).
1
–
mode of the sensor with CN in DMSO was shown in Fig. 2.
The selectivity of a chemosensors for an anionic species is
related to its differential ability to interact with the receptor
site in the chemosensor, for instance, through intermolecular
hydrogen-bonding [25].
From Fig. 5, the value of Kbinding is found to be 2.5 (± 0.26)
6
–1
1
10 M . Compound S is a simpler sensor, it has only one
×
polycyclic aromatic system based on benzimidazole group and
has a hydroxyl group as a binding site, which could detect
This interaction produces fluorescent complex com-
–
pounds. The interaction between receptor and CN anion
occured via hydrogen bonding between the hydrogen atoms
on the OH cluster (anion binding site) of the receptor with
–
CN anion. This interaction produces electron delocalization
–
CN ion at concentration of S
1
is 0.1 µM producing LOD value
–6
(obtained from the calculation [(3×SD)/slope]) is 1.2 × 10
M at addition of 50 equivalent ion.
in fluorescens unit so that the receptor becomes fluorescence.
–7
A sensory with two polycyclic aromatics system based
on benzimidazol group and naphthalene group, also has one
hydroxyl group as a binding site, it has been used to detect
At a concentration of 1 × 10 M sensor molecule absorbs at
ex 305 nm and emits light at λem 358 nm with a maximum
λ
–6
–
intensity: 121303. The addition 5 × 10 M of ion CN causes
the absorption λex 320 nm and emission of light on λem 360
nm with a maximum intensity: 1.09794 (Fig. 3).
–
CN ion at concentration of sensor is 20 µM producing LOD
–
8
8
.8 × 10 M [12]. So, S
1
compound is more sensitive because
Signal site
OCH3
OCH3
N
–
N
CN
Binding
O
OH
site
DMSO
N
H
N
H
H
–
CN
–
and CN in DMSO
Fig. 2. Possible binding model between compound S
1
1
200000
000000
1
200000
–
800000
Sensor + CN
ion 1000 eq.
Sensor (S)
S+ion eq.1
S+ion eq.2
S+ion eq.3
S+ion eq.4
S+ion eq.5
S+ion eq.6
S+ion eq.7
S+ion eq.8
700000
(c)
1
(a)
(b)
1000000
800000
600000
8
6
4
2
00000
00000
00000
00000
0
500000
6
4
2
00000
00000
00000
400000
300000
200000
100000
0
Sensor
0
3
3
00
400
500
600
700
300
400
500
600
00
400
Wavelength (nm)
500
Wavelength (nm)
Wavelength (nm)
–
[10 M] in DMSO solution upon adding of an increasing of CN (a); titration of 50 µL CN 50 eq. λem 320 nm (b);
7
–
–
Fig. 3. Fluorescence titration spectra of S
1
–
titration of 50 µL CN 1000 eq. λem 432 nm (c)

1
962 Rahmawati et al.
Asian J. Chem.
REFERENCES
210
1
2
.
.
H. Khanmohammadi, K. Rezaeian and A. Abdollahi, Spectrochim. Acta A,
39, 405 (2015);
https://doi.org/10.1016/j.saa.2014.12.088.
2
00
1
190
X. Shang, Y. Wang, X. Wei, Z. Fu, J. Zhang and X. Xu, Molecules, 18,
14840 (2013);
https://doi.org/10.3390/molecules181214840.
180
3
4
.
.
N. Dikshit, M. Tiwari and A. Dewan, Natl. J. Med. Res., 4, 106 (2014).
G.J. Park, I.H. Hwang, E.J. Song, H. Kim and C. Kim, Tetrahedron,
170
70, 2822 (2014);
https://doi.org/10.1016/j.tet.2014.02.055.
160
5
.
R.M.F. Batista, R.C.M. Ferreira, M.M.M. Raposo and S.P.G. Costa,
Tetrahedron, 68, 7322 (2012);
https://doi.org/10.1016/j.tet.2012.06.087.
1
50
140
6
7
.
.
Z. Karimi-Jaberi and M. Amiri, E-J. Chem., 9, 167 (2012);
https://doi.org/10.1155/2012/793978.
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
X. Bao and Y. Zhou, Sens. Actuators B Chem., 147, 434 (2010);
https://doi.org/10.1016/j.snb.2010.03.068.
(
X
)/[(X )+(X
ion
)]
ion
sensor
–
Fig. 4. Job’s plot of fracsimole of CN ion
8. G.J. Park,Y.W. Choi, D. Lee and C. Kim, Spectrochim. Acta A, 132, 771
2014);
https://doi.org/10.1016/j.saa.2014.06.001.
(
1
100000
9. O. Çimen, H. Dinçalp and C. Varlikli, Sens. Actuators B Chem., 209,
853 (2015);
https://doi.org/10.1016/j.snb.2014.12.056.
1
050000
000000
1
1
0. L. Chen, H. Nie, G. Zhang, F. Gong, Y. Yang, C. Gong, Q. Tang and K.
Xiao, Tetrahedron Lett., 55, 3017 (2014);
https://doi.org/10.1016/j.tetlet.2014.03.097.
1
1. S.-Y. Na and H.-J. Kim, Tetrahedron Lett., 56, 493 (2015);
https://doi.org/10.1016/j.tetlet.2014.12.083.
9
9
8
8
7
50000
00000
50000
00000
50000
1
12000
110000
12. J.-B. Li, J.-H. Hu, J.-J. Chen and J. Qi, Spectrochim. Acta A, 133, 773
2014);
1
1
1
1
1
08000
06000
04000
02000
00000
(
https://doi.org/10.1016/j.saa.2014.06.060.
13. Y. Zhang, B. Zou, Z. Chen, Y. Pan, H. Wang, H. Liang and X. Yi,
Bioorg. Med. Chem. Lett., 21, 6811 (2011);
https://doi.org/10.1016/j.bmcl.2011.09.029.
9
9
9
9
8000
6000
4000
2000
Y = 5.955X + 6.447
2
R
= 0.904
1
1
1
4. N. Kaur, G. Dhaka and J. Singh, Tetrahedron Lett., 56, 1162 (2015);
https://doi.org/10.1016/j.tetlet.2015.01.128.
0.000
0.002
0.004
0.006
0.008
3
0.010
–
Concentration (×10
)
5. A.S. Gupta, K. Paul and V. Luxami, Inorg. Chim. Acta, 443, 57 (2016);
https://doi.org/10.1016/j.ica.2015.11.024.
0.000
0.002
0.004
0.006
0.008
0.010
–3
Concentration (×10 )
6. W. Zheng, X. He, H. Chen, Y. Gao and H. Li, Spectrochim. Acta A, 124,
97 (2014);
https://doi.org/10.1016/j.saa.2013.12.098.
– –3
Fig. 5. Plot titrations fluorescence CN ion (in 10 M value); (insert) non-
–
linear calibration curve of titration CN ion
1
7. Y.-C. Wang, L.-Z. Liu, Y.-M. Pan and H.-S. Wang, Molecules, 16, 100
(2010);
https://doi.org/10.3390/molecules16010100.
–
it can detect CN ion at lower concentration than WHO standard
at lower concentration of sensor.
1
1
8. L. Jun, L. Qi,Y.M. Zhang and T.B. Wei, Sci. China Chem., 57, 1257 (2014);
https://doi.org/10.1007/s11426-014-5108-9.
Conclusion
9. T.B. Nguyen, J.L. Bescont, L. Ermolenko andA. Al-Mourabit, Org. Lett.,
15, 6218 (2013);
https://doi.org/10.1021/ol403064z.
A new compound as fluorescence chemosensor for anion
were synthesized and studied by spectrofluorometry spectra.
Chemosensor 4-(1H-benzimidazol-2-yl)-2-methoxy-phenol
showed specially highly sensitivity fluorescence recognition
20. Y. Kim, M.R. Kumar, N. Park, Y. Heo and S. Lee, J. Org. Chem., 76, 9577
(
2011);
https://doi.org/10.1021/jo2019416.
21. M. Rekha, A. Hamza, B.R. Venugopal and N. Nagaraju, Chin. J. Catal.,
3, 439 (2012);
–7
–
(in 1 × 10 M) for CN in DMSO solution. The sensor demons-
trates the detection limit on fluorescence respons of the sensor
3
–
–6
to CN is 1.2 × 10 M, which is lower than the WHO guideline
https://doi.org/10.1016/S1872-2067(11)60338-0.
2. W. Cui, R.B. Kargbo, Z. Sajjadi-Hashemi, F. Ahmed and J.F. Gauuan,
Synlett, 247 (2012);
2
–
6
[
12] of 1.9 × 10 M.
ACKNOWLEDGEMENTS
The authors are grateful for financial grant from Penelitian
https://doi.org/10.1055/s-0031-1290129.
23. V. Reena, S. Suganya and S. Velmathi, J. Fluor. Chem., 153, 89 (2013);
https://doi.org/10.1016/j.jfluchem.2013.05.010.
4. J. Shao, Dyes Pigments, 87, 272 (2010);
2
2
Unggulan Perguruan Tinggi (PUPT), Universitas Gadjah Mada
with contract number 918/UN-P.III/CT/Dit-Lit/2016; dated
st
March 1 2016.
https://doi.org/10.1016/j.dyepig.2010.04.007.
5. C.R. Nicoleti,V.G. Marini, L.M. Zimmermann andV.G. Machado, J. Braz.
Chem. Soc., 23, 1488 (2012);
https://doi.org/10.1590/S0103-50532012005000007.
6. H. Su, H. Lin, Z. Cai and H. Lin, J. Incl. Phenom. Macrocycl. Chem., 67, 183
2
(2010);
https://doi.org/10.1007/s10847-009-9695-6.