Synthesis of tweezer type receptors for colorimetric detection of cyanide ions

Article abstract of DOI:10.1007/s10847-016-0593-4

Two tweezer type receptors based on the hydrazone functional group using o-phthalaldehyde moiety as spacer were synthesized and characterized via 1H, 13CNMR, MALDI-MS and single crystal X-ray crystallographic techniques. The anion sensing abilities of the

Full text of DOI:10.1007/s10847-016-0593-4

J Incl Phenom Macrocycl Chem
DOI 10.1007/s10847-016-0593-4
ORIGINAL ARTICLE
Synthesis of tweezer type receptors for colorimetric detection
of cyanide ions
Priya Ranjan Sahoo1 Pragati Mishra1 Palak Agarwal1
•
•
•
Nikita Gupta1 Satish Kumar1
•
Received: 20 October 2015 / Accepted: 5 January 2016
Ó Springer Science+Business Media Dordrecht 2016
Abstract Two tweezer type receptors based on the
hydrazone functional group using o-phthalaldehyde moiety
as spacer were synthesized and characterized via 1H,
13CNMR, MALDI-MS and single crystal X-ray crystallo-
graphic techniques. The anion sensing abilities of the
synthesized receptors were investigated in DMSO using
UV–Visible spectroscopy and naked eye detection. The
crystal structure revealed the presence of a DMSO mole-
cule in the cavity of the receptor. A receptor displayed the
formation of dark red color visible to the naked eye in the
presence of cyanide ions. The complex between the
receptor and the cyanide ion proceeds through displace-
ment of the DMSO molecule present in the cavity of the
receptor. The stoichiometry of the complex between the
receptor and the cyanide ion was determined by job’s plot.
The proton NMR spectroscopy and the DFT calculations
were used to study the mechanism of the complex
formation.
Graphical Abstract
Keywords Cyanide ion detection Á Sensors Á Hydrazone Á
Crystal structure Á Optical recognition
Introduction
Ubiquitous anions play a prominent role in a variety of
chemical and physical phenomena. Due to extensive use of
anions in various industrial processes, there is widespread
release of anions into the natural habitat as pollutants [1].
The abundance of highly toxic cyanide anion is extremely
high in dyes, paints, herbicides and leather industry [2, 3].
& Satish Kumar
satish@ststephens.edu
1
Department of Chemistry, St. Stephen’s College, University
Enclave, Delhi 110007, India
123

J Incl Phenom Macrocycl Chem
It is well known that the toxic cyanide ions act in the living
organisms through coordination with iron present in the
active site of an enzyme cytochrome c, which disrupt the
electron transport chain in mitochondria, reducing the
oxygen utilization and oxidative metabolism. There are
evidences to support the claim that cyanide ions plays an
important role in blocking cellular respiration to attack
central nervous system [4, 5]. The unavoidable usages of
cyanide ions in prominent fields like mineral processing,
electroplating and gold industry further creates a need for
CN- detection and quantification [6, 7]. Cyanide contam-
ination also originate from biological aspects [8]. In order
to keep pace with industrial revolution, quick and easy
detection of toxic anions particularly cyanide ions is
extremely important for environmental protection and
monitoring [1]. Therefore, there is a strong need for effi-
cient probe for selective and sensitive detection of cyanide
ions. The winds of anion sensing has strengthened from
recent past under the banner of visual and optical responses
and other methods [9, 10]. Visual detection of anion
through distinct color change is quite simple and most
noteworthy [11]. The detection of anionic species is
dependent on hydrogen bonding and electrostatic interac-
tions etc. [12]. The receptor-CN recognition relies on the
ability of CN- ion towards effective interaction with host
molecule [13]. In order to ensure effective binding of
anionic species with the receptor, the functional groups
such as amines, amides, ureas and thioureas have already
been incorporated into the structure of the synthetic
receptors to achieve strong hydrogen bonding interactions
[14–16].
Keeping the nucleophilicity concept of CN- in mind, the
research group led by Hong have designed coumarin based
sensor for in vitro detection of CN- species [17]. The other
groups led by Yoon have also developed mono and di
aldehyde based hydroxyl fluorescein probes for cyanide
recognition [18, 19]. They have also injected the DMSO
solution of the probe into the lungs of mice in order to image
cyanide inside the mice body. The reported sensing probes
also include dipyrrole carboxamide [20], azo phenyl
thiourea [21], disperse orange-3 derivative [22], substituted
N-nitrophenyl benzamide [23], nitro azo salicylaldehyde
[24], dipyrrin derivatives [25] and N-acyl triazene scaffolds
[26].
effect of nitro groups in anion coordination and the cage
effect using DFT studies were also evaluated.
Experimental
Reagents
All the reagents o-phthalaldehyde, 2, 4-dinitro phenyl
hydrazine, 4-nitrophenyl hydrazine, THF and acetic acid
were purchased from spectrochem, India. All the tetrabutyl
ammonium salts of various anions were purchased from
CDH AR grade.
Instruments
The NMR spectra were recorded on a 400 MHz Jeol
spectrometer. The IR spectrum was recorded on a Perkin
Elmer FT-IR-RXI spectrometer. Elemental analysis was
performed on elementar analysensysteme Germany Vario
Micro Cube CHNSO system at USIC facility. Single
crystal data was recorded on an Oxford Diffraction,
X-caribur-S single crystal XRD machine.
UV–Visible studies
A 1.0 mL solution of chelator 1 (2.5 9 10-5 M) was
prepared in a quartz cuvette and 1.0 mL of different anions
(2.5 9 10-5 M) were mixed well and the UV visible
spectrum was recorded on an Ocean Optics USB4000 UV–
Visible spectrometer.
Computations
Calculations reported in this paper were performed using
Gaussian 09 program [27]. The initial geometry of the
receptor 2 was generated using Gaussview 5.0 program
[27]. The geometries generated using Gaussview were
optimized using DFT/B3LYP/6-31G(d) method. The local
minimum for the optimized structure was confirmed
through absence of negative frequency. The time depen-
dent DFT method was used to obtain the transition energy
and absorption spectra.
To induce anion coordination to the synthetic receptors,
it is necessary to maximize the polarizing tendency of the
N–H group of the receptor, which can be achieved through
the electron withdrawing groups like –NO2 to enhance the
anion coordination ability.
Synthesis
Synthesis of receptor 1
In a round bottom flask (150 mL), o-phthalaldehyde (0.5 g,
3.73 mmol) and 4-nitrophenyl hydrazine (1.26 g,
8.28 mmol) were dissolved in THF (10 mL). The mixture
was warmed over heating mantle and kept for 15–20 min
In this article, we present the synthesis and evaluation of
colorimetric sensor for cyanide ion, which possess hydra-
zone groups with –NO2 substituents. The sensor was
observed to be selective for cyanide ions in DMSO. The
123

J Incl Phenom Macrocycl Chem
followed by the addition of 2–3 drops of acetic acid. The
precipitates were filtered and washed with little THF. The
product was purified through recrystallization using THF
and dried. Yield 0.64 g m.pt. 238–240 °C. FT-IR (KBr,
m/cm-1): 3450, 2928, 2852, 1642, 1390 and 1086. 1H-NMR
(400 MHz, DMSO-d6): d = 11.45 (s, 2H), 8.51 (s, 2H)
8.14 (d, 4H, J = 8.4 Hz), 7.86 (dd, 4H, J = 6 Hz) 7.43
(dd, 4H, J = 6 Hz), 7.19 (d, 2H, J = 8.4 Hz). 13C-NMR
(100 MHz, DMSO-d6): d = 150.5, 140.7, 138.6, 132.25,
129.5, 127.8, 126.2, 111.5. MALDIMS: m/z = Calculated
404.1233; found [M?1]?: 405.0601. C20H16N6O4 CHN %
Calcd. C: 59.30, H: 3.99, N: 20.78; found C: 59.53, H:
3.92, N: 20.03.
Fig. 1 ORTEP [28] view of crystal structure of receptor 2 with
displacement ellipsoids at the 50 % probability level (CCDC
1416520)
Synthesis of receptor 2
In a round bottom flask (150 mL), o-phthalaldehyde (0.5 g,
3.73 mmol) and 2, 4-dinitrophenylhydrazine (1.26 g,
8.28 mmol) were dissolved in 10 mL THF. The reaction
mixture was warmed and kept for 15–20 min followed by the
addition of 2–3 drops of acetic acid. The precipitated product
was filtered followed by washing with small amount of THF.
The product was recrystallized twice with THF and dried to
give yellow-orange product. Yield 0.54 g. m.pt: 230–232 °C
FT-IR (KBr, m/cm-1): 2922, 2852, 1740, 1615, 1581, 1462,
1333, 1264, 1139, 992, 908, 720. 1H-NMR (400 MHz,
DMSO-d6): d = 11.8(s, 1H) 9.9 (brs, 2H), 9.19 (s, 1H) 8.9 (s,
1H), 8.4–8.0 (m, 8H), 7.6–7.5 (m, 1H). MALDI-MS:
m/z = Calculated 496.1013; found [M]?: 496.2639
[M?Na]: 517.2861; C20H14N8O8 CHN% Calcd. C: 48.59,
H: 2.85, N: 22.67; found C: 49.00, H: 2.88, N: 22.37.
˚
Table 1 Hydrogen-bond geometry (A, °)
D—HÁÁÁA
D—H HÁÁÁA DÁÁÁA
D—HÁÁÁA
N005—H005ÁÁÁO2
0.86
0.86
0.86
0.93
0.93
2.00
2.00
1.99
2.54
2.50
2.38
2.84
2.66
2.62
2.53
2.63
2.46
2.56 (5)
122.1
128.1
127.2
157.1
167.5
153.3
N005—H005ÁÁÁO2A
N008—H008ÁÁÁO00E
C00O—H00OÁÁÁO00Gi
C00Q—H00QÁÁÁO004ii
2.619 (9)
2.603 (6)
3.416 (7)
3.418 (7)
3.240 (9)
C00V—H00VÁÁÁO013iii 0.93
C00V—H00VÁÁÁS0iii
C00V—H00VÁÁÁO0iii
C015—H01CÁÁÁO00Div
C015—H01CÁÁÁN00Fiv
C3—H3CÁÁÁO009v
0.93
0.93
0.96
0.96
0.96
0.96
3.562 (18) 135.2
3.32 (5)
128.8
139.7
133.3
3.411 (9)
3.263 (9)
3.549 (18) 159.5
3.23 (4) 137.3
C3A—H3ACÁÁÁO3Avi
Symmetry codes (i) x ? 1, y, z - 1; (ii) x - 1, y, z ? 1; (iii) x,
-y ? 1/2, z ? 1/2; (iv) x, -y ? 1/2, z - 1/2; (v) x - 1, y, z; (vi) -x,
-y ? 1, -z ? 1
Result and discussion
Crystallographic studies
(DMSO) molecules (Fig. 1). One solvent molecule DMSO
occupies the cavity of the receptor while another DMSO
solvent molecule resides closer to the nitro group and is
coordinated through weak intermolecular interactions. Two
intramolecular N–HÁÁÁO hydrogen bonds are present in the
asymmetric unit. The structure is characterized by several
short intermolecular and intramolecular hydrogen bonds
The receptors were synthesized as per the Scheme 1 in
moderate to high yield and characterized by IR, NMR,
Mass and elemental analyses. Single crystals of receptor 2
suitable for data collection were grown through slow
evaporation method. The asymmetric unit in the crystal
structure of the receptor 2 is solvated by two solvent
Scheme 1 The synthesis route
of the receptor 1 and 2
123

J Incl Phenom Macrocycl Chem
variations or color change to the naked eye was observed
with other anions (Fig. 4).
UV–Visible studies
UV–Visible spectra indicates that the receptor 2 absorb at
400 nm with a small shoulder peak at 540 nm. The pres-
ence of a small absorption band at 540 nm indicates the
formation of an inclusion complex between DMSO and
receptor 2. The absorption band at 540 nm was not
observed in the spectrum of receptor 2 in THF. The for-
mation of receptor 2-DMSO inclusion complex was also
supported by X-ray crystallographic studies, which indi-
cates that the DMSO molecule occupies the receptor 2
cavity (Fig. 1). The absorption peak at 400 nm decreased
in intensity and 540 nm increased in intensity on the
addition of one equivalent of cyanide ion, which indicated
that the complex between cyanide ions and the receptor 2 is
stronger than the complex between DMSO and receptor 2.
Further, the 2 - CN complex is formed through displace-
ment of DMSO molecule. Other interfering anions such as
F-, OAc- did not show any change on the absorbance
profile indicating the selectivity of receptor 2 towards CN-
ion which produced a clearly visible deep red color from an
orange solution. The respective variation in absorbance
with respect to different anions is depicted in the Fig. 5.
However, the receptor 1 did not respond to the presence of
any of the anions tested. It is pertinent to note that the only
difference between receptor 1 and 2 is the number of nitro
groups which suggests the important role nitro groups play
in the recognition process. In addition, the fact that receptor
2 selectively recognize, a more nucleophilic and less basic
cyanide ion in comparison to the fluoride or other anion
suggest that pka (pKa: [29] F = 15, CN = 12.9,
OAc = 12.6, Cl = 1.8, Br = 0.9) of anion is not solely
responsible for the observed selectively, other factors such
as size, geometry and nucleophilicity of the anions are also
important (Figs. 6, 7).
Fig. 2 Crystal packing diagram of receptor 2 viewed along axis b
showing intermolecular short contacts. Ellipsoids are shown at 50 %
probability level
(Table 1). The crystal packing diagram (Fig. 2) suggested
that the solvent molecule occupies the space between the
layers of the receptor molecule. The solvent molecules
were bound to the receptor molecules through short inter-
molecular H-bonds involving oxygen atom of the DMSO
and H-atoms connected to the nitrogen. Two nitroaromatic
units are at 101.08° dihedral angle to each other. The two
DMSO solvent molecules were highly disordered and
modeled using SIMU, FREE and EADP instructions.
Naked eye detection
The synthesized receptors were explored for colorimetric
response towards different anions in DMSO. In order to
evaluate the anion binding preference, standard solutions of
the receptors 1 and 2 (1 9 10-4 M) were prepared in
DMSO. UV–Visible spectral variation experiments in the
presence of 1 equivalent of different anions were per-
formed: No color change was observed with receptor 1 in
the presence of different anionic species (Fig. 3). It was
observed that the addition of 1 equivalent cyanide ions to a
solution of receptors 2 in DMSO produced a visible change
in color along with spectral variation while no spectral
The two nitro groups played a key role in better charge
separation in comparison to a single nitro group due to
which color changed from yellow to red [30] as reported in
the literature which also suggests that nitro group plays an
important role in anion coordination [31]. Anion binding
Fig. 3 Colour change on the addition of 1.0 equivalent of tetrabutyl ammonium anions into a solution of receptor 1 in DMSO. [1] = 5.0 9 10-5
.
-
From left to right; A = Free receptor, B = CN-, C = F-, D = OAc-, E = Cl-, F = Br-, G = I-, H = NO3-, I = H2PO4-, J = HSO4
123

J Incl Phenom Macrocycl Chem
Fig. 4 Color change on the addition of 1.0 equivalent of tetrabutyl
ammonium anions into
B = CN-, C = F-, D = OAc-, E = Cl-, F = Br-, G = I-,
H = NO3-, I = H2PO4-, J = HSO4-, K = PF6-, L = PhO-
a solution of receptor 2 in DMSO.
From left to right; A = Free receptor,
[2] = 5.0 9 10-5
.
1.3
1.1
0.9
0.7
0.5
0.3
0.1
-0.1
0.35
0.3
Free and other anions
CN-
0.25
0.2
0.15
0.1
0.05
0
0
0.2
0.4
0.6
0.8
1
1.2
300
350
400
450
500
550
600
650
700
[H2L]/([H2L]+[CN-])
Wavelength (nm)
Fig. 7 Job’s plot between receptor 2 and CN- ion in DMSO.
Absorbance at 499 nm was plotted as a function of the molar ratio
[H2L]/([H2L]?[CN-])
Fig. 5 Absorption spectra of 2 ([2] = 2.5 9 10-5 M) with 1.0
equivalent of n-butyl ammonium salt of various anions ([F-], [Cl-],
[Br-], [I-], [HSO4-], [H2PO42-], [PF6-], [NO3-], [OAc-],
[PhO-] = 2.5 9 10-5 M) in DMSO. For simplicity spectra of only
few important anions are shown
formation of a stable complex between the receptor 2 and
CN-. A reasonable bathochromic shift of 135 nm was
experienced during complex formation. Finally, the color
changed from yellow to dark red. The stoichiometry of the
complex was confirmed through Job’s plot, which indi-
cated it to be 1:1. No such characteristics were observed in
the case of other anions.
0.5
0.4
0.3
0.2
0.1
0
In order to determine the binding strength of receptor
towards CN- ions, binding affinity studies were performed
using Hypspec [34]. When the results were analyzed using
Hypspec, a logb value of 4.7527 0.0013 was obtained
indicating a strong complex between cyanide ions and the
receptor 2 in DMSO.
300
400
500
600
700
Wavelength (nm)
Fig. 6 UV–Vis spectrum of the receptor 2 [2] = 2.5 9 10-5 M in
the presence of cyanide ions ([CN-] = 0–4.12 9 10-5 M) in DMSO
In order to obtain the detection limit of the synthesized
receptor 2 towards cyanide ion, UV–Visible absorbance
was plotted against the cyanide ion concentration. A linear
change in the absorbance intensity with increasing cyanide
ion concentration was obtained (Fig. 8), which was used for
calculation of detection limit based on 3r/m, where r is the
standard deviation and m is the slope of the intensity versus
cyanide concentration plot. A detection limit of UV–Visible
spectrophotometry was obtained as 1.4 lM which is less
than the WHO prescribed limit for cyanide ion as 1.9 lM.
was also attributed to H-bond interactions [23]. The bind-
ing sites containing highly polarized N–H group were also
reported for recognition of anions [32]. The highly polar-
ized group may deprotonate in the presence of anions,
which causes substantial electron delocalization and ulti-
mately produce a different absorption spectral band and the
visual color change [33].
In order to further understand the binding process, a
titration experiment was performed. Upon gradual addition
of a solution of cyanide ion solution in DMSO to a solution
of receptor 2 in DMSO, the absorption peak at 400 nm
gradually decreased and a peak at 550 nm appeared. A
clearly distinguishable isosbestic point was observed at
451 nm. The distinct isosbestic point confirmed the
NMR studies
To investigate the mechanism of complex formation
between the cyanide ion and the receptor 2, the NMR
123

J Incl Phenom Macrocycl Chem
0.26
0.24
0.22
0.20
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
found to be the most stable (Table 2). Rotation of
nitroaromatic group or the CN group destabilized the
structure. The same conformer was also observed in single
crystal X-ray crystallographic studies. Therefore, anion
binding studies were also performed using the same con-
formers. Various binding modes were optimized to pro-
vide the lowest energy complex geometry shown in
Fig. 10c–f (Table 2) using B3LYP/6-31G(d) method. The
geometry shown in Fig. 10d provided the lowest energy
among all the binding modes. The presence of two cyanide
ions per receptor 2 molecule was observed to be sterically
unfavourable. The structure shown in Fig. 10d was
observed to be more stable by -99.23 kcal/mol
[DE = Ecomplex - ECN - E(2)] in comparison to the free
receptor 2 and cyanide ion combined energy indicating
that the stability of the complex. Further, the solvation
energy of the receptor 2 and 2 ? CN complex was cal-
culated in DMSO (Table 2). It was observed that the
receptor 2 was more solvated than the complex, indicating
that the solvent interact with the receptor 2 through
H-bond interactions. The formation of a complex between
cyanide ions and the receptor 2 reduces this interaction
due to the presence of HCN in the receptor cavity. To
further investigate the observed bathochromic shift in UV–
Visible spectra on the addition of cyanide ions, time-de-
pendent DFT studies using 6-31G(d) basis set were per-
formed using the Gaussian 09 software suite. The Table 3
lists various parameters calculated for electronic transition
using TD-DFT/6-31G(d) in receptor 2 and 2 ? CN com-
plex. The singlet excitations in receptor 2 were mainly
contributed by HOMO to LUMO (So to S1) and HOMO to
LUMO?2 (So to S3) orbitals. The energy (2.87 eV,
432 nm) of HOMO to LUMO?2 transition (So to S3) is
close to the observed absorption maxima in DMSO
(Table 3; Fig. 11). The total change in dipole moment was
determined to be 30.07 debye, which indicated deproto-
nation of N-H and generation of high negative charge in
the receptor 2 as suggested by NMR data [36]. Similarly,
the transition between HOMO to LUMO (So to S1) and
HOMO to LUMO?1 (So to S2) orbitals contribute mainly
to the singlet excitation in the 2 - CN complex. The
energy (2.18 eV, 568 nm) for the transition between
HOMO to LUMO?1 is close to the observed maxima in
DMSO (Table 3; Fig. 11). The bathochromic shift
observed during the complex formation between cyanide
ions and the receptor 2 can be explained by comparing the
calculated singlet excitation energy observed in 2 - CN
complex and the receptor 2. A small singlet excitation
energy in the 2 - CN complex indicates a bathochromic
shift. Further, the cyanide binding to the receptor 2 leads
to the delocalization of electron density in receptor 2
causing bathochromic shift (Fig. 11).
Equation
Adj. R-Square
y = a + b*x
0.99072
Value
0.11274
0.01065
Standard Error
0.00365
B
B
Intercept
Slope
5.14713E-4
0
2
4
6
µ
8
10
12
14
-
[CN ]
M
Fig. 8 Determination of detection limit of receptor 2 for cyanide ion
at 547 nm
2+CN
2
11.3
10.3
9.3
ppm
8.3
7.3
Fig. 9 1H-NMR spectra of receptor 2 [2] = 60 mM and 2 ? CN
(cyanide ions 1.0 eq.) in DMSO-d6
spectra of receptor 2 and receptor 2 ? CN ions in DMSO-
d6 were recorded (Fig. 9). It was observed that the NH
group signal appeared at d 11.80 and d 9.19 in proton NMR
spectra of receptor 2. The proton NMR signal of NH proton
disappeared at d 11.80 while the other N–H signal at d 9.19
shifted to lower ppm value when cyanide ions were added
to the receptor 2 in DMSO-d6. The NMR indicates that the
receptor 2 detect cyanide ions through deprotonation pro-
cess which resulted in color change.
Computational studies
In order to further understand the binding process at the
molecular level, density functional theory was used [35].
Calculations were performed at B3LYP/6-31G(d) level as
they have been used to predict the properties of such
systems successfully. Various conformers of the receptor 2
were optimized. The conformer shown in Fig. 10a was
123

J Incl Phenom Macrocycl Chem
Fig. 10 The B3LYP/6-31G(d) optimized geometries of a receptor 2 and 2 - CN complex modes between receptor 2 and cyanide ion
Table 2 The energy of the
Structure
Energy (Hartree)
Energy (kcal/mol)
DGsolv (kcal/mol), DMSO
receptor 2 and 2 ? CN
calculated using DFT/B3LYP/6-
31G(d) method
9a
9b
9c
9d
9e
9f
-1809.92194505
-1809.88526064
-1902.82,646,010
-1902.90461024
-1902.84196484
-1809.39721827
-1,135,742.31
-1,135,719.29
-1,194,040.73
-1,194,089.77
-1194050.46
-1,135,413.04
-15.92
0.0009
Table 3 Electronic excitation
parameters for receptor 2 and
2 ? CN complex obtained
using TD-DFT/6-
Receptor
CIC
E(eV)[k(nm)]
lx
ly
lz
ltotal
f
2
So to S1
So to S2
So to S3
2 ? CN
So to S1
So to S2
H to L (0.69)
2.59 (478.86)
2.72 (455.42)
2.87 (431.90)
7.92
0.00
-2.50
0.00
-0.17
0.00
24.68
4.82
0.6161
0.1265
0.8323
31G(d) method
H to L ? 1 (0.69)
H to L ? 2 (0.69)
0.00
8.74
0.21
30.07
H to L (0.70)
1.96 (632.89)
2.18 (568.21)
-3.97
-0.23
-0.77
0.16
0.05
6.23
0.1178
0.2887
H to L ? 1 (0.70)
5.86
13.72
123

J Incl Phenom Macrocycl Chem
Fig. 11 Energy diagrams for
main orbitals of 2 and 2 - CN
complex calculated using the
DFT/B3LYP/6-31G method
fluorescent cyanide chemosensor: utilization of the nucleophilic
addition induced by resonance-assisted hydrogen bond. Tetrahe-
dron 71(5), 857–862 (2015)
Conclusion
In conclusion, we have reported the design and synthesis of
two simple hydrazone based tweezer type receptors for
cyanide ions. The receptor produced selective and sensitive
colorimetric response towards cyanide ions visible to the
naked eye as well as the distinct absorbance change in UV–
Vis spectra. A single isosbestic point was observed in the
cyanide titration profile. The job’s plot also confirmed 1:1
complex stoichiometry between cyanide ions and the
receptor 2. The binding titration experiment using Hypspec
package also confirmed strong binding affinity of the
receptor 2 for CN- ions. The mechanism of complexation
was investigated using DFT and NMR experiments, which
confirmed that the complex formation involve N-H proton
abstraction by cyanide ions.
3. Ravikanth, M., Dvivedi, A., Rajakannu, P.: Meso-salicylaldehyde
substituted BODIPY as chemodosimetric sensor for cyanide
anion. Dalton Trans. 44, 4054–4062 (2015)
4. Ashton, T.D., Jolliffe, K.A., Pfeffer, F.M.: Luminescent probes
for the bioimaging of small anionic species in vitro and in vivo.
Chem. Soc. Rev. 44, 4547–4595 (2015)
5. Hu, J., Li, J., Qi, J., Sun, Y.: Selective colorimetric and ‘‘turn-on’’
fluorimetric detection of cyanide using an acylhydrazone sensor
in aqueous media. New J. Chem. 39, 4041–4046 (2015)
6. Mudder, T., Botz, M.: Cyanide and society: a critical review.
Ejmp Ep 4(1), 62–74 (2004)
7. Isaad, J., El Achari, A.: A novel glycoconjugated N-acetylamino
aldehyde hydrazone azo dye as chromogenic probe for cyanide
detection in water. Anal. Chem. Acta 694(1), 120–127 (2011)
8. Wang, F., Wang, L., Chen, X., Yoon, J.: Recent progress in the
development of fluorometric and colorimetric chemosensors for
detection of cyanide ions. Chem. Soc. Rev. 43(13), 4312–4324 (2014)
9. You, L., Zha, D., Anslyn, E.V.: Recent Advances in
Supramolecular Analytical Chemistry Using Optical Sensing.
Chem, Rev (2015)
Acknowledgments Authors sincerely thank UGC (No.41-235/
2012) and DST (No. SR/FT/CS-054/2012), New Delhi, India for
financial support. Authors are thankful to the Director, USIC
University of Delhi for instrumental facilities. The authors are also
thankful to the Principal, St. Stephen’s College for providing the
necessary infrastructure.
10. Kwon, H., Jiang, W., Kool, E.T.: Pattern-based detection of anion
pollutants in water with DNA polyfluorophores. Chem. Rev. 6(4),
2575–2583 (2015)
11. Lee, H.J., Park, S.J., Sin, H.J., Na, Y.J., Kim, C.: A selective
colorimetric chemosensor with an electron-withdrawing group
for multi-analytes CN- and F-. New J., Chem (2015)
12. Dalapati, S., Jana, S., Guchhait, N.: Anion recognition by simple
chromogenic and chromo-fluorogenic salicylidene Schiff base or
References
reduced-Schiff base receptors. Spectrochim. Acta
499–508 (2014)
13. Zhang, C., Liu, C., Li, B., Chen, J., Zhang, H., Hu, Z., Yi, F.: A
new fluorescent ‘‘turn-on’’ chemodosimeter for cyanide based on
dual reversible and irreversible deprotonation of NH and CH
groups. New. J, Chem (2015)
A 129,
1. Gale, P.A., Caltagirone, C.: Anion sensing by small molecules
and molecular ensembles. Chem. Soc. Rev. 44, 4212–4227
(2015)
2. Li, Q., Zhang, J.-H., Cai, Y., Qu, W.-J., Gao, G.-Y., Lin, Q., Yao,
H., Zhang, Y.-M., Wei, T.-B.:
A facile colorimetric and
123

J Incl Phenom Macrocycl Chem
14. Xu, Z., Chen, X., Kim, H.N., Yoon, J.: Sensors for the optical
detection of cyanide ion. Chem. Soc. Rev. 39(1), 127–137 (2010)
15. Kaur, N., Dhaka, G., Singh, J.: Simple naked-eye ratiometric and
colorimetric receptor for anions based on azo dye featuring with
benzimidazole unit. Tetrahedron Lett. 56, 1162–1165 (2015)
16. Robbins, T.F., Qian, H., Su, X., Hughes, R.P., Aprahamian, I.:
Cyanide detection using a triazolopyridinium salt. Org. Lett.
15(10), 2386–2389 (2013)
27. Frisch, M.J., Trucks, G.W., et al.: Gaussian 09, Revision A02.
Gaussian, Inc, Wallingford (2009)
28. Macrae, C.F., Bruno, I.J., Chisholm, J.A., Edgington, P.R.,
McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R.,
Streek, J.V., Wood, P.A.: Mercury CSD 2.0–new features for the
visualization and investigation of crystal structures. J. Appl.
Cryst. 41(2), 466–470 (2008)
29. Taft, R.W., Bordwell, F.G.: Structural and solvent effects eval-
uated from acidities measured in dimethyl sulfoxide and in the
gas phase. Acc. Chem. Res. 21(12), 463–469 (1988). doi:10.
1021/ar00156a005
17. Lee, K.-S., Kim, H.-J., Kim, G.-H., Shin, I., Hong, J.-I.: Fluo-
rescent chemodosimeter for selective detection of cyanide in
water. Org. Lett. 10(1), 49–51 (2008)
18. Kwon, S.K., Kou, S., Kim, H.N., Chen, X., Hwang, H., Nam, S.-
W., Kim, S.H., Swamy, K., Park, S., Yoon, J.: Sensing cyanide
ion via fluorescent change and its application to the microfluidic
system. Tetrahedron Lett. 49(26), 4102–4105 (2008)
19. Nam, S.-W., Chen, X., Lim, J., Kim, S.H., Kim, S.-T., Cho, Y.-
H., Yoon, J., Park, S.: In vivo fluorescence imaging of bacteri-
ogenic cyanide in the lungs of live mice infected with cystic
fibrosis pathogens. PLoS One 6(7), e21387 (2011)
30. Zhu, X., Lin, Q., Lou, J.-C., Lu, T.-T., Zhang, Y.-M., Wei, T.-B.:
Colorimetric probes designed to provide high sensitivity and
single selectivity for CN- in aqueous solution. New J. Chem.
39(9), 7206–7210 (2015). doi:10.1039/c5nj01158b
31. Kim, D.-S., Chung, Y.-M., Jun, M., Ahn, K.H.: Selective col-
orimetric sensing of anions in aqueous media through reversible
covalent bonding. J. Org. Chem. 74(13), 4849–4854 (2009)
32. Park, J., Kang, J.: A new colorimetric anion sensor which have
both a fat brown RR dye and a nitrophenyl group as signaling
group. J. Incl. Phenom. Macrocycl. Chem. 69(1–2), 57–61
(2011). doi:10.1007/s10847-010-9813-5
20. Chen, C.-L., Chen, Y.-H., Chen, C.-Y., Sun, S.-S.: Dipyrrole
carboxamide derived selective ratiometric probes for cyanide ion.
Org. Lett. 8(22), 5053–5056 (2006)
21. Gimeno, N., Li, X., Durrant, J.R., Vilar, R.: Cyanide sensing with
organic dyes: studies in solution and on nanostructured Al2O3
surfaces. Chem. Eur. J. 14(10), 3006–3012 (2008)
22. Niu, H.-T., Jiang, X., He, J., Cheng, J.-P.: A highly selective and
synthetically facile aqueous-phase cyanide probe. Tetrahedron
Lett. 49(46), 6521–6524 (2008)
23. Sun, Y., Wang, G., Guo, W.: Colorimetric detection of cyanide
with N-nitrophenyl benzamide derivatives. Tetrahedron 65(17),
3480–3485 (2009)
24. Lee, K.-S., Lee, J.T., Hong, J.-I., Kim, H.-J.: Visual detection of
cyanide through intramolecular hydrogen bond. Chem. Lett.
36(6), 816–817 (2007)
33. Choi, Y., Kang, J.: Chromogenic anion receptors based on 4-ni-
trophenylhydrazone and phenylhydrazone. J. Incl. Phenom.
Macrocycl. Chem. 79(1–2), 95–102 (2014). doi:10.1007/s10847-
013-0328-8
34. Gans, P., Sabatini, A., Vacca, A.: Investigation of equilibria in
solution. Determination of equilibrium constants with the
HYPERQUAD suite of programs. Talanta 43(10), 1739–1753
(1996)
35. Satheshkumar, A., El-Mossalamy, E.H., Manivannan, R., Par-
thiban, C., Al-Harbi, L.M., Kosa, S., Elango, K.P.: Anion induced
azo-hydrazone tautomerism for the selective colorimetric sensing
of fluoride ion. Spectrochim. Acta A 128, 798–805 (2014).
doi:10.1016/j.saa.2014.02.200
36. Nelson Jr, R.D., Lide Jr, D.R., Maryott, A.A.: Selected values of
electric dipole moments for molecules in the gas phase. In. DTIC
Document, (1967)
25. Ding, Y., Li, T., Zhu, W., Xie, Y.: Highly selective colorimetric
sensing of cyanide based on formation of dipyrrin adducts. Org.
Biomol. Chem. 10(21), 4201–4207 (2012). doi:10.1039/
c2ob25297j
26. Chung, Y., Ahn, K.H.: N-acyl triazenes as tunable and selective
chemodosimeters toward cyanide ion. J. Org. Chem. 71(25),
9470–9474 (2006)
123