Phenanthroimidazole and dicyanovinyl-substituted triphenylamine for the selective detection of CN?: DFT calculations and practically applications

Article abstract of DOI:10.1016/j.jphotochem.2019.112328

A novel CN^? selective fluorescent turn-on sensor (TPMN) possessing triphenylamine and phenanthroimidazole as signaling units and dicyanovinyl unit for the binding site was designed and synthesized. TPMN exhibited a drastic change in its emissio

Full text of DOI:10.1016/j.jphotochem.2019.112328

Journal Pre-proof
Phenanthroimidazole and dicyanovinyl-substituted triphenylamine for the
selective detection of CN-: DFT calculations and practically applications
Ahmet Ozdemir (Conceptualization) (Investigation), Serkan Erdemir
(Conceptualization) (Project administration) (Writing - review and
editing)
PII:
S1010-6030(19)31647-8
DOI:
https://doi.org/10.1016/j.jphotochem.2019.112328
JPC 112328
Reference:
To appear in:
Journal of Photochemistry & Photobiology, A: Chemistry
Received Date:
Revised Date:
Accepted Date:
24 September 2019
11 December 2019
17 December 2019
Please cite this article as: Ozdemir A, Erdemir S, Phenanthroimidazole and
dicyanovinyl-substituted triphenylamine for the selective detection of CN-: DFT calculations
and practically applications, Journal of Photochemistry and amp; Photobiology, A: Chemistry
(2019), doi: https://doi.org/10.1016/j.jphotochem.2019.112328
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1
Phenanthroimidazole and dicyanovinyl-substituted triphenylamine for the
selective detection of CN-: DFT calculations and practically applications
Ahmet Ozdemir and Serkan Erdemir*
Department of Chemistry, Selcuk University, 42075 Konya, Turkey
*Author for correspondence. Tel.: +903322233853, fax: +903322232499
E-mail: serdemir82@gmail.com
Graphical Abstract
Highlights

Cyanide selective triphenylamine and phenanthroimidazole based a probe (TPMN)
were developed
 TPMN indicated high selectivity and sensitivity for CN- in the presence of most
anions
 The limits of detection of TPMN for sensing CN- is down to 0.23 M
 The practical performance of TPMN was successfully observed on the TLC kits and
water samples
Abstract
A novel CN- selective fluorescent turn-on sensor (TPMN) possessing triphenylamine
and phenanthroimidazole as signaling units and dicyanovinyl unit for the binding site was

2
designed and synthesized. TPMN exhibited a drastic change in its emission spectra with about
13-fold fluorescence enhancement when treated with CN-, while other tested anions could not
arouse the fluorescence enhancement. The experimental and theoretical calculation results
showed that this increase in fluorescence intensity of TPMN in presence of CN- is due to the
large decrease in the ICT effect by the addition of CN- ion to β-carbon of the dicyanovinyl
moiety. TPMN could selectively detect CN- with a detection limit of 0.23 µM among the
common anions. The CN--binding mode was well-characterized to be 1:1 by using Job’s
plot with an association constant of 5.36 (logKa). Besides, the possible utilization of TPMN
was successively tested in water samples and test kits.
Keywords: Triphenylanime, phenanthroimidazole, cyanide, fluorescent
___________________________________________________________________________
1. Introduction
Cyanide (CN-) is one of the highly toxic species in environmental and biological
systems due to its inhibition of cellular respiration [1]. In addition to presence in numerous
foodstuffs and plants, cyanide is generally used in numerous chemical processes, such as
metal plating and mining, medicines, the plastic-based materials and fertilizers [2]. Because
the maximum permissive level of CN- in drinking water is as low as 1.9 µM (WHO) [3], it is
extremely necessary to efficiently and safely monitor a residual concentration of cyanide.
Unlike other known analytical methods, chromogenic and fluorogenic sensors for the
detection of cyanide by the naked eye have remarked much interest in consequence of the
easy detection, fast usage, low cost, high sensitivity and remote control [4, 5].
Many strategies for detecting as fluorometric and colorimetric of CN− have been
reported in recent years, involving the mechanism of coordination [6, 7], CdSe quantum dots
[8, 9], the displacement approach [10], hydrogen-bond interactions [11], deprotonation [12],
and nucleophilic addition reactions [13-15]. Among these methods, the nucleophilic addition
reaction of CN- induces the formation of the new covalent bond and indicates high selectivity,
anti-interference ability [16]. Some of these chemosensors have high limits of detection or
show only moderate selectivity towards cyanide and, in some cases, cyanide cannot be
determined in aqueous solution. Thus, fluorescent and colorimetric sensors with a low
detection limit, high sensitivity, and selectivity for CN- in aqueous solutions are still needed.
In the present study, we have synthesized a novel probe (TPMN) with common D–π–A

3
structural, which contain dicyanovinyl group as electron acceptor (A), and triphenylamine and
phenanthroimidazole groups as the electron donor (D). Upon the nucleophilic Michael
addition of cyanide anion to the dicyanovinyl unit, TPMN indicated good selectivity,
sensitivity and short response time in MeCN/H2O (v/v, 9/1) towards CN- due to inhibited ICT
effect.
2. Experimental
2.1. Materials and methods
Some materials such as triphenylamine, malononitrile, 9,10-phenanthrenequinone, TFA
(trifluoroacetic acid) and HMTA (hexamethylenetetramine) were obtained from Sigma-
1
Aldrich and ACROS. H, 13C, and APT NMR analysis were carried out in DMSO-d6 on a
Bruker 400 MHz spectrometer. The fluorescence and UV-vis spectra were measured using a
Perkin Elmer LS 55 and a Shimadzu 1280 spectrophotometer, respectively. Also, FTIR
analysis were realized on a Bruker FTIR instrument. The excitation wavelength for
fluorescence measurements was 390 nm.
2.2. Synthesis
2.2.1.
N-(4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)-4-(1H-phenanthro[9,10-
d]imidazol-2-yl)-N-phenylaniline (2)
For the synthesis of compound 2, triphenylamine-dialdehyde derivative (1) was firstly
synthesized via Vilsmeier-Haack reaction by using POCl3 in DMF [17]. Then, a solution of
compound 1 (300 mg, 1.0 mmol), 9,10-Phenanthrenequinone (420 mg, 2.0 mmol) and
ammonium acetate (310 mg, 4.0 mmol) in acetic acid (20 mL) was refluxed for 6h. At the end
of this period, the produced beige solid was filtered, and dried to give 2. Yield: 84%; Mp >
o
1
350 C ; H NMR (400 MHz, DMSO-d6):  13.40 (br s, 2H, NH), 8.85 (d, 4H, J=8.62 Hz,
ArH), 8.58 (d, 4H, J=8.62 Hz, ArH), 8.29 (d, 4H, J=8.71 Hz, ArH), 7.74 (d, 4H, J=7.68 Hz,
ArH), 7.63 (d, 4H, J=7.68 Hz, ArH), 7.44 (t, 2H, J=8.06 Hz, ArH), 7.30 (d, 4H, J=7.68 Hz,
ArH), 7.21-7.25 (m, 3H, ArH).
2.2.2. 4-(bis(4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)amino)benzaldehyde (3)
To solution of 2 (500 mg, 0.74 mmol) in TFA (50 mL), HMTA (620 mg, 4.44 mmol)
was added under stirring. The resulting mixture was refluxed for 24 h to complete the
reaction. Then, a solution of HCl (1.0ꢀM, 100ꢀmL) was interacted with this reaction mixture.

4
After the stirring for 1ꢀh, the dark green colored product was precipitated. The filtered 3 was
o
1
then recrystallized from ethanol. Yield: 67%; Mp:282-284 C; FTIR: 1660 cm-1 (CHO); H
NMR (400 MHz, DMSO-d6):  9.89 (s, 1H, CHO), 8.86 (d, 4H, J=8.30 Hz, ArH), 8.56 (d,
4H, J=8.30 Hz, ArH), 8.33 (d, 4H, J=8.41 Hz, ArH), 7.89 (d, 2H, J=8.73 Hz, ArH), 7.75 (d,
4H, J=7.35 Hz, ArH), 7.67 (t, 4H, J=7.35 Hz, ArH), 7.42 (d, 4H, J=8.60 Hz, ArH), 7.26 (d,
2H, J=8.73 Hz, ArH).
2.2.3.2-(4-(bis(4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)amino)benzylidene)
malononitrile (TPMN)
TPMN was obtained by Knoevenagel condensation reaction between 3 and
malononitrile. For this, a solution of 3 (352 mg, 0.5 mmol) and malononitrile (33 mg, 0.5
mmol) in DMF (5.0 mL) was stirred in presence of Zn(OAc)2·2H2O (110 mg, 0.5 mmol) at
room temperature. The color of the reaction mixture turned from light yellow to red in this
period. After 2h, the reaction mixture was interacted with water (20 mL), and stirred for 1h.
The product TPMN precipitated as red power was filtered, and then dried. Yield: 90%;
o
1
Mp:255-257 C; FTIR: 2220 cm-1 (CN); H NMR (400 MHz, DMSO-d6):  13.50 (br s, 2H,
NH), 8.82 (d, 4H, J=8.71 Hz, ArH), 8.56 (d, 4H, J=7.68 Hz, ArH), 8.37 (d, 4H, J=8.36 Hz,
ArH), 8.22 (s, 1H, C=CH), 7.84 (d, 2H, J=8.85 Hz, ArH), 7.72 (t, 4H, J=7.71 Hz, ArH), 7.61
13
(t, 4H, J=7.71 Hz, ArH), 7.43 (d, 4H, J=8.51 Hz, ArH), 7.10 (d, 2H, J=8.85 Hz, ArH). C
NMR (100 MHz, DMSO-d6):  162.77, 159.84, 152.47, 148.88, 146.18, 133.46, 128.42,
128.14, 127.65, 126.80, 125.89, 124.71, 124.43, 122.44, 120.68, 115.67, 114.70, 75.86; Anal.
Calcd for C52H31N7 (753.26): C, 82.85; H, 4.15; N, 13.01. Found: C, 83.01; H, 4.22; N, 13.15.
2.3. Analytical measurements and theoretical calculations
-
-
-
-
The tetrabutylammonium forms of anions (F-, Cl-, Br-, I-, CN-, NO3 , NO2 , N3 , HSO4 ,
-
2-
2-
H2PO4 , HPO4 , ClO-, AcO-, OH-, SO4 , SCN-) were used to prepare their solutions (10.0
mM) in pure water. A stock solution (10ꢀmM) of TPMN was prepared in DMSO. Then, it
was diluted to 10 µM and 20 µM with MeCN/H2O (9/1, v/v) for fluorescence and UV-vis
studies, respectively. To perform the fluorescence and UV-vis titration experiments, the anion
solutions were gradually added to a 3.0ꢀmL solution of TPMN by using a micro-pipette. The
obtained titration results were used in the determination of association constant (logK) and
1
detection limit (DL) values. H NMR titration experiments were realized by addition of CN-
(0.0, 0.5, 1.0, and 1.5 equiv.) to a solution of TPMN (0.079 M) in DMSO-d6. Moreover, the
nature of the sensing mechanism between TPMN with CN- was determined by molecular

5
modeling. The density functional theory (DFT) calculations were accomplished for
optimization of TPMN and TPMN-CN- complex at the B3LYP/6-31G level (Gaussian 2016)
[18].
3. Results and discussion
3.1. Production of TPMN
TPMN was successfully produced by Vilsmeier-Haack reaction [17], the formation of
phenanthroimidazole [19], Duff reaction [20] and Knoevenagel condensation [21],
respectively (Scheme 1). After the Vilsmeier-Hack reaction of triphenylamine, the reaction of
the obtained triphenylamine’s dialdehyde derivative (2) with 9,10-phenanthrenequinone in the
presence of NH4OAc generated the triphenylamine conjugated with two phenanthroimidazole
groups (2) with a 68 % yield. The product 2 was then transformed to its aldehyde derivative
(3) in the presence of HMTA and TFA by Duff reaction. Finally, compound 3 was condensed
with malononitrile using Knoevenagel condensation in the presence of Zn(OAc)2.2H2O in
DMF to provide TPMN in good yield (90%). The characterization of TPMN was made by
using FTIR, 1H, 13C, APT NMR and elemental analysis (Figs. S1–S7).
3.2.
Optical properties of TPMN towards anions
To observe the optical properties, UV–vis and fluorescence spectroscopies of TPMN
in MeCN/H2O (v/v, 9/1) were recorded in absence or presence of anions (F-, Cl-, Br-, I-, CN-,
-
-
-
-
-
-
2-
NO3 , NO2 , N3 , HSO4 , H2PO4 , HPO4 , ClO-, AcO-, OH-, SO4 , SCN-). As shown in Fig. 1a,
free TPMN (1.0 µM) showed weak fluorescence emission at 430 and 435 nm due to the ICT
effect from the triphenylamine and phenanthroimidazole units to the dicyanovinyl group via
π-conjugation. Nevertheless, the addition of CN- (10 equiv.) produced an effective emission
enhancement at 430 and 435 nm, whereas other anions were induced no noticeable changes in
the fluorescence spectrum of TPMN. This selectivity is the result of the nucleophilic addition
of the CN- ion to the β-position of the dicyanovinyl carbon in TPMN. The nucleophilic
reaction of CN- conducted to inhibiting the ICT process in TPMN due to disrupts the π-
conjugation between electron donor and acceptor groups [22]. On the other hand, the UV-vis
properties of TPMN (10.0 µM) towards anions were also studied. As depicted in Fig. 1b, the
absorption bands of TPMN appeared at ∼382 and 462 nm, which ascribed to the -* or n-*
transitions and the intramolecular charge transfer (ICT) processes, respectively. The
absorption band at 462 nm disappeared after 10 equiv. CN- was added, and the color of the

6
solution converted from yellow to colorless (Fig. 1b, inset). However, no obvious UV-vis
changes for TPMN were observed upon the addition of other anions. It may due to the
nucleophilic addition of CN- and destroyed the conjugated structure of TPMN.
To insight the interaction between TPMN and CN-, we carried out the UV-vis and
fluorescence titration experiments of TPMN with varying equivalents of CN-. With the
increasing concentration of CN- from 0 to 20 µM, the fluorescence intensities at 430 and 445
nm of TPMN have exhibited a remarkable increase, indicating that TPMN was a turn-on
fluorescent probe for CN- (Fig.2a). The increase of fluorescence intensity was near to the
maximum when about 20 equiv. of CN- (20 μM) was added. At the same time, the titration
curve showed an excellent linear relationship between the emission intensities and the
concentrations of CN-. According to these data, the limit of detection (DL) was found to be
0.23 µM based on 3σ/k, suggesting that TPMN has a high sensitivity for CN- (Fig. S8) [23].
The binding ratio between TPMN and CN- was further determined by using Job’s plot
analysis (Fig. S9). As seen in Fig. S9, when the mole fraction of CN- is 0.5, the change of
fluorescence became maximum, which showed a 1:1 stoichiometric ratio between TPMN and
CN-. The Benesi–Hildebrand plot was used to determine the association constant of TPMN
for CN-, and it was also found to be 5.36 (logKa) (Fig. S10) [24]. The quantum yield of
TPMN (ΦTPMNꢀ=0.046) reached to 0.522 for cyanide (Fig. S11). The results indicated that
quantum yield of TPMN was increased ~11-fold for cyanide. Besides, the UV-vis changes
were investigated by the addition of CN- (0–200ꢀμM) into 10ꢀμM solution of TPMN. The
absorption band centered at 462ꢀnm gradually decreased and then completely disappeared
without any blue shift by addition of CN-, and the bands at 382 and 388 nm slightly decreased
and increased, respectively (Fig. 2b). Additionally, the formation of an isosbestic point at 418
nm indicated that the reaction of TPMN with CN- was one-to-one conversion to form a new
compound.
To investigate the photophysical properties of TPMN, the solvent effect in the
absorption and emission spectra were also investigated. As shown in Fig. S12, solvent
dependent shifts in the absorption and emission spectra of TPMN occurred. By plotting the
Stokes shifts () against the solvent polarity parameter (f), show approximately a linear
relationship according to the Lippert–Mataga plot [25], showing a positive slope and a good
linear relationship (R = 0.9447). The change of the solvent polarity indicated the enhancement
or diminished the electron density in the structure, as well as the intermolecular charge
transfer (ICT) due to the interaction with the solvent.

7
3.3. Competition, kinetic studies, and practical applications
Selectivity and competition are important parameters for fluorescent sensors. Thus, to
check the selectivity of TPMN for CN-, a solution of TPMN was incubated with CN- and 10
equiv. of other anions and their emission spectra were recorded. As shown in Fig.3, the
TPMN indicated unaltered signaling for CN− in the presence of other anions. These selective
and anti-interference of the TPMN to CN- was probably owing to the high reactivity of
cyanide ion to the β-position of the dicyanovinyl moiety in TPMN. Therefore, TPMN could
be utilized as an effective probe for CN- detection in a complex environment. Compared with
other reported probes including dicyanovinyl unit as receptor unit for fluorescence cyanide
detection, the present method shows a comparable response due to its promising properties
low detection limit, high selectivity and sensitivity, rapid response and environmental analysis
[26-30]
To evaluate the performance of TPMN, time-dependent absorbance changes to TPMN
(10.0 µM) for CN- (100.0 µM) were recorded in MeCN/H2O (v/v, 9/1). As shown in Fig. 4,
upon the introduction of CN-, the absorbance intensities at 462 nm was gradually decreased
depending on time and reached a maximum within about 10 s. After 10 s., any change in the
absorbance intensity could not be observed. The reaction rate constant of TPMN with CN-
was found to be 0.119 min-1 assuming pseudo-first-order kinetics (Fig.4, inset).
To control the accuracy of the proposed method, after the supernatant in water samples
(i.e., tap, distilled and mineral water) were removed using a 0.45 µm pore size membrane
filter, different concentrations level of CN- were spiked in water samples. The prepared water
samples were then conducted to the presented procedure. As listed in Table 1, the recovery
values were generally higher than 95%, and the RSD values were less than 3.6%, illustrating
that TPMN could be used for direct detection of CN- in relevant real water samples. On the
other hand, the practical application of TPMN by high sensitivity and selectivity for CN- was
observed by simple test kits. TLC plates were immersed into the TPMN solution (10-6 M, 3
mL) for 2 min to produce the test kits and then dried in air. These test kits were interacted by
CN- solution with different concentrations. As depicted in Fig. 5, whereas the test kit coated
TPMN showed no apparent emission, the test kits containing a different concentration of CN-
emitted bright blue-fluorescence, providing the test strips can be applied to detect CN-
qualitatively and quantitatively.
3.4. 1H NMR experiments and DFT calculations

8
1H NMR titration of TPMN (0.079M) was realized by adding of CN- in DMSO-d6 at
o
25 C in order to determine the interaction mechanism between TPMN and CN-, As
illustrated in Fig 6, the vinyl (CH) and NH proton signals of TPMN were observed at  8.22
and  13.50 ppm without CN-, respectively. The NH protons appeared as two separate peaks
due to probably hydrogen binding effect, and the vinyl CH signal was shifted downfield (
8.24 ppm) by the addition of 0.5 equiv. of CN-. Also, the different splits were observed for
aromatic protons in TPMN. When the amount of CN- was increased to 1.0 equiv., the NH
signal was observed as one peak at  13.43 ppm, the vinyl CH signal at  8.24 ppm vanished
and a new proton signal at 4.59 ppm emerged. This new peak support that the -C=C- bond is
broken by the CN- attack giving rise to the formation of the C–C single bond. Upon the
1
addition of 1.5 equiv. of CN-, no obvious spectral changes were observed in H NMR,
indicating that the reaction is complete.
DFT calculations were carried out to evidence the ICT transition and further explain
the changes of fluorescence intensity before and after the reaction between TPMN and CN-.
The optimized structures and frontier HOMO-LUMO orbitals of TPMN and TPMN-CN- are
shown in Fig. 7 and 8, respectively. The optimized structures illustrated that there is a
significant difference of π-conjugation between TPMN and TPMN-CN-. As seen in Fig. 7, the
dihedral angle of dicyanovinyl and benzene of triphenylamine moiety in TPMN is 1.45o,
which showed in-plane. The addition of CN- induced to destroy of this planer geometry, then
the dihedral angle converted to be 101.03o. It demonstrates that the interrupting of π-
conjugation and ICT transfer between triphenylamine-phenanthroimidazole groups and
dicyanovinyl unit. Also, the bond distances and bond angles in TPMN and TPMN-CN- were
found to be 1.376 Å/114.134o and 1.540 Å/107.113o, which supports the change -C=C- bond
to -C-C- bond, respectively.
The HOMO and LUMO orbitals of TPMN and TPMN-CN- were illustrated in Fig. 8.
In the case of TPMN, HOMO is primarily distributed on the triphenylamine and
phenanthroimidazole ring whereas LUMO is majorly located on the dicyanovinyl group,
showing the possible ICT pathway from donor to acceptor. However, the HOMO and LUMO
orbitals of TPMN-CN- distributed solely within the triphenylamine and phenanthroimidazole
moieties which indicates the obstruction in the ICT process, resulting in enhanced
fluorescence emission. The energy gap (ΔE) of TPMN was found to be 2.93ꢀeV, and after
cyanide addition, the ΔE increased significantly to 3.81ꢀeV, which are in good agreement with
the changes in the UV-vis spectra. Also, TD-DFT calculations showed that the excitation

9
wavelengths of TPMN and TPMN-CN- are 495 and 425 nm, respectively, supporting to the
obtained results in experiments (462 and 390 nm). These theoretical calculations were in
consistent with the experimental results, by means of complete disappearance of ICT band at
495ꢀnm of when CN- attack TPMN (Fig. S13).
4. Conclusion
In summary, the phenanthroimidazole and dicyanovinyl substituted triphenylamine
derivative as a fluorescent probe was produced for selective CN- detection. Only the addition
of CN- to TPMN induced a remarkable emission enhancement at 430 nm which results in
restricting the donor-acceptor extended π-conjugation. TPMN also demonstrated a fast
response time (~10ꢀs) for CN-, which could be effective for real-time detection. The sensing
mechanism was characterized by 1H NMR measurements and DFT/TD-DFT calculations. The
limit of detection was found to be 0.23 µM, which indicated good sensitivity to CN-.
Moreover, TPMN has successfully integrated into test strips for real-time detection of CN-
and applied to detect CN− in water samples.
AUTHOR STATEMENT
Ahmet Ozdemir: Conceptualization, Investigation Serkan Erdemir: Conceptualization,
Project administration, Writing – review and editing
Declaration of interests
The authors declare that they have no known competing financial interests or personal
relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
We thank the Scientific and Technical Research Council of Turkey (TUBITAK-Grant
Number 119Z659) and the Research Foundation of Selcuk University (BAP) for financial
support.

10
References
[1] A. Bianchi, K. Bowman-James, E. Garcìa-España, Supramolecular chemistry of anions,
Vch Pub, 1997.
[2] G. Miller, C. Pritsos, Cyanide: society, industrial and economic aspects, in: Proc Symp
Annu Meet TMS, 2001.
[3] W.H. Organization, Guidelines for drinking-water quality, World Health Organization,
1993.
[4] I. Yahaya, Z. Seferoglu, Fluorescence Dyes for Determination of Cyanide, Photochemistry
and Photophysics: Fundamentals to Applications, (2018) 179.
[5] Z. Xu, X. Chen, H.N. Kim, J. Yoon, Sensors for the optical detection of cyanide ion,
Chemical Society Reviews, 39 (2010) 127-137.
[6] J.H. Lee, A.R. Jeong, I.-S. Shin, H.-J. Kim, J.-I. Hong, Fluorescence turn-on sensor for
cyanide based on a cobalt (II)− coumarinylsalen complex, Organic letters, 12 (2010) 764-767.
[7] M.T. Gabr, F.C. Pigge, A fluorescent turn-on probe for cyanide anion detection based on
an AIE active cobalt (II) complex, Dalton Transactions, 47 (2018) 2079-2085.
[8] W.J. Jin, M.T. Fernández-Argüelles, J.M. Costa-Fernández, R. Pereiro, A. Sanz-Medel,
Photoactivated luminescent CdSe quantum dots as sensitive cyanide probes in aqueous
solutions, Chemical Communications, (2005) 883-885.
[9] A. Touceda-Varela, E.I. Stevenson, J.A. Galve-Gasion, D.T. Dryden, J.C. Mareque-Rivas,
Selective turn-on fluorescence detection of cyanide in water using hydrophobic CdSe
quantum dots, Chemical Communications, (2008) 1998-2000.
[10] Z. Xu, J. Pan, D.R. Spring, J. Cui, J. Yoon, Ratiometric fluorescent and colorimetric
sensors for Cu2+ based on 4, 5-disubstituted-1, 8-naphthalimide and sensing cyanide via
Cu2+ displacement approach, Tetrahedron, 66 (2010) 1678-1683.
[11] W.-T. Gong, Q.-L. Zhang, L. Shang, B. Gao, G.-L. Ning, A new principle for selective
sensing cyanide anions based on 2-hydroxy-naphthaldeazine compound, Sensors and
Actuators B: Chemical, 177 (2013) 322-326.
[12] S. Erdemir, S. Malkondu, On-site and low-cost detection of cyanide by simple
colorimetric and fluorogenic sensors: Smartphone and test strip applications, Talanta, (2019)
120278.
[13] F. Huo, J. Kang, C. Yin, J. Chao, Y. Zhang, A turn on fluorescent sensor for cyanide
based on ICT off in aqueous and its application for bioimaging, Sensors and Actuators B:
Chemical, 215 (2015) 93-98.
[14] X. Lv, J. Liu, Y. Liu, Y. Zhao, Y.-Q. Sun, P. Wang, W. Guo, Ratiometric fluorescence
detection of cyanide based on a hybrid coumarin–hemicyanine dye: the large emission shift
and the high selectivity, Chemical Communications, 47 (2011) 12843-12845.
[15] Q. Zhang, Y. Zhang, S. Ding, H. Zhang, G. Feng, A near-infrared fluorescent probe for
rapid, colorimetric and ratiometric detection of bisulfite in food, serum, and living cells,
Sensors and Actuators B: Chemical, 211 (2015) 377-384.
[16] Y. Shiraishi, M. Nakamura, T. Kogure, T. Hirai, Off–on fluorometric detection of
cyanide anions in an aqueous mixture by an indane-based receptor, New Journal of
Chemistry, 40 (2016) 1237-1243.
[17] O.M.-C.a.S. P.Stanforth, The Vilsmeier–Haack Reaction, Comprehensive Organic
Synthesis, 2 (1991) 777-794.
[18] M. Frisch, G. Trucks, H. Schlegel, G. Scuseria, M. Robb, J. Cheeseman, G. Scalmani, V.
Barone, G. Petersson, H. Nakatsuji, Gaussian 16, Revision A. 03, Gaussian, Inc., Wallingford
CT, 2016, There is no corresponding record for this reference.[Google Scholar], (2019).
[19] S. Damavandi, New approach to the multicomponent one-pot synthesis of 2-aryl-1H-
phenanthro [9, 10-d] imidazoles, Heterocyclic Communications, 17 (2011) 79-81.

11
[20] O. Alici, S. Erdemir, A cyanobiphenyl containing fluorescence “turn on” sensor for Al3+
ion in CH3CN–water, Sensors and Actuators B: Chemical, 208 (2015) 159-163.
[21] Y. Yang, B. Li, L. Zhang, Design and synthesis of triphenylamine-malonitrile derivatives
as solvatochromic fluorescent dyes, Sensors and Actuators B: Chemical, 183 (2013) 46-51.
[22] Z. Li, Y. Dai, Z. Lu, Y. Pei, Y. Song, L. Zhang, H. Guo, A photoswitchable triple
chemosensor for cyanide anion based on dicyanovinyl‐ functionalized dithienylethene,
European Journal of Organic Chemistry, 2019 (2019) 3614-3621.
[23] T.G. Jo, Y.J. Na, J.J. Lee, M.M. Lee, S.Y. Lee, C. Kim, A multifunctional colorimetric
chemosensor for cyanide and copper (II) ions, Sensors and Actuators B: Chemical, 211
(2015) 498-506.
[24] H.A. Benesi, J. Hildebrand, A spectrophotometric investigation of the interaction of
iodine with aromatic hydrocarbons, Journal of the American Chemical Society, 71 (1949)
2703-2707.
[25] N. Mataga, Y. Kaifu and M. Koizumi, Solvent effects upon fluorescence spectra and the
dipole moments of excited molecules, Bull. Chem. Soc. Jpn., 28 (1955) 690–691
[26] J.Orrego-Hernꢁndez, J. Portill, Synthesis of Dicyanovinyl-Substituted 1‑ (2-
Pyridyl)pyrazoles: Design of a Fluorescent Chemosensor for Selective Recognition of
Cyanide, The Journal of Organic Chemistry, 82 (2017) 13376-13385
[27] P. B. Pati, S. S. Zade, Dicyanovinyl terthiophene as a reaction based colorimetric and
ratiometric fluorescence probe for cyanide anions, RSC Advances, 3 (2013) 13457-13462
[28] K.Y. Chen, W.C. Lin, A simple 7-azaindole-based ratiometric fluorescent sensor for
detection of cyanide in aqueous media, Dyes and Pigments, 123 (2015) 1-7
[29] E.Thanayupong, K. Suttisintong, M. Sukwattanasinitt, N. Niamnont, Turn-on fluorescent
sensor for the detection of cyanide based on a novel dicyanovinyl phenylacetylene, New
Journal of Chemistry, 41 (2017) 4058-4064
[30] W.C. Lin, S.K. Fang, J.W. Hu, H.Y. Tsai, K.Y. Chen, Ratiometric
Fluorescent/Colorimetric Cyanide-Selective Sensor Based on Excited-State Intramolecular
Charge Transfer−Excited State Intramolecular Proton Transfer Switching, Analytical
Chemisty, 86 (2014) 4648−4652

12
Figure Captions
Scheme 1. Synthetic route for TPMN. Reagents and conditions (i): DMF, POCl3 (ii): 9,10-
Phenanthrenequinone, ammonium acetate, acetic acid, 6h (iii): HMTA, TFA, 24h (iv):
malononitrile, Zn(OAc).2H2O, 2h.
Fig. 1. Fluorescence (a) and UV-vis response (b) of TPMN in presence of various anions (10
equiv.) in MeCN/H2O (v/v, 9/1).
Fig.2. Fluorescence emission (a) and UV-vis spectra of TPMN in MeCN/H2O (v/v, 9/1) upon
addition of various concentrations of CN-.
Fig.3. Competitive experiments of TPMN (1.0 M) for CN- (10.0 equiv.) in the presence of
common anions (10.0 equiv.) in in MeCN/H2O (v/v, 9/1) solution.
Fig.4. The kinetic study of TPMN (10 μM) to CN- at room temperature under pseudo-first-
order condition.
Table 1. Determination of CN- ions in spiked water samples using TPMN
Fig.5. Color changes of TLC plates containing TPMN for CN- detection in different
concentrations under 365ꢀnm UV light
1
Fig.6. H NMR spectra of TPMN in the absence and presence of CN- (a=0.0, b=0.5, c=1.0
and d=1.5 equiv.) in DMSO-d6
Fig. 7. DFT calculated optimized structures of TPMN and TPMN-CN-
Fig. 8. Frontier molecular orbital diagrams and energy levels of TPMN and TPMN-CN-. by
DFT at the B3LYP/6-31G /level using Gaussian 16

13
Scheme 1. Synthetic route for TPMN. Reagents and conditions (i): DMF, POCl3 (ii): 9,10-
Phenanthrenequinone, ammonium acetate, acetic acid, 6h (iii): HMTA, TFA, 24h (iv):
malononitrile, Zn(OAc).2H2O, 2h.

14
a
b
Fig. 1. Fluorescence (a) and UV-vis response (b) of TPMN in presence of various anions (10
equiv.) in MeCN/H2O (v/v, 9/1).

15
a
b
Fig.2. Fluorescence emission (a) and UV-vis spectra of TPMN in MeCN/H2O (v/v, 9/1) upon
addition of various concentrations of CN-.

16
Fig.3. Competitive experiments of TPMN (1.0 M) for CN- (10.0 equiv.) in the presence of
common anions (10.0 equiv.) in in MeCN/H2O (v/v, 9/1) solution.
Fig.4. The kinetic study of TPMN (10 μM) to CN- at room temperature under pseudo-first-
order condition.

17
Table 1. Determination of CN- ions in spiked water samples using TPMN
Sample
Added CN- (µM)
Found (µM)
Recovery (%)
RSD (Relative standard
deviation) (n=3) (%)
5.0
4.79 ± 0.3
9.75 ± 0.3
4.95 ± 0.2
10.12 ± 0.4
4.77 ± 0.3
9.89 ± 0.5
95.8
97.5
99.0
101.2
95.4
98.9
2.4
3.3
2.1
3.0
3.6
2.5
Tap Water
10.0
5.0
Distilled water
Mineral water
10.0
5.0
10.0
Fig.5. Color changes of TLC plates containing TPMN for CN- detection in different
concentrations under 365ꢀnm UV light

18
1
Fig.6. H NMR spectra of TPMN in the absence and presence of CN- (a=0.0, b=0.5, c=1.0
and d=1.5 equiv.) in DMSO-d6

19
Fig. 7. DFT calculated optimized structures of TPMN and TPMN-CN-
Fig. 8. Frontier molecular orbital diagrams and energy levels of TPMN and TPMN-CN-. by
DFT at the B3LYP/6-31G /level using Gaussian 16