The novel sensitive and selective chemosensors for determination of multiple analytes

Article abstract of DOI:10.1016/j.dyepig.2020.108701

Novel chemosensors that are azo dyes bearing coumarin with indole and thiophene recognition moieties were synthesized. Sensor properties of the dyes were investigated within multiple basic environments that include various pH ranges, anions, and organic a

Full text of DOI:10.1016/j.dyepig.2020.108701

Journal Pre-proof
The novel sensitive and selective chemosensors for determination multiple analytes
Deniz ÇAKMAZ, Arda ÖZARSLAN, Burcu AYDINER, Ahmet Burak EROĞLU, Nurgül
SEFEROĞLU, Hülya ŞENÖZ, Zeynel SEFEROĞLU
PII:
S0143-7208(20)31398-X
DOI:
https://doi.org/10.1016/j.dyepig.2020.108701
DYPI 108701
Reference:
To appear in: Dyes and Pigments
Received Date: 13 March 2020
Revised Date: 6 July 2020
Accepted Date: 6 July 2020
Please cite this article as: ÇAKMAZ D, ÖZARSLAN A, AYDINER B, EROĞLU AB, SEFEROĞLU N,
ŞENÖZ H, SEFEROĞLU Z, The novel sensitive and selective chemosensors for determination multiple
analytes, Dyes and Pigments, https://doi.org/10.1016/j.dyepig.2020.108701.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition
of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of
record. This version will undergo additional copyediting, typesetting and review before it is published
in its final form, but we are providing this version to give early visibility of the article. Please note that,
during the production process, errors may be discovered which could affect the content, and all legal
disclaimers that apply to the journal pertain.
©
2020 Elsevier Ltd. All rights reserved.

1
1
2
The novel sensitive and selective chemosensors for determination multiple
analytes
3
4
5
6
7
8
9
a
a,b
a,*
c
Deniz ÇAKMAZ , Arda ÖZARSLAN , Burcu AYDINER , Ahmet Burak EROĞLU ,
c
b*
a
Nurgül SEFEROĞLU , Hülya ŞENÖZ , Zeynel SEFEROĞLU
a
Department of Chemistry, Faculty of Science, Gazi University, Ankara 06560, Turkey
b
Department of Chemistry, Faculty of Science, Hacettepe University, Ankara 06800, Turkey
c
Department of Advanced Technology, Gazi University, Ankara 06560, Turkey
1
1
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
8
9
Abstract
Novel chemosensors that are azo dyes bearing coumarin with indole and thiophene
recognition moieties were synthesized. Sensor properties of the dyes were investigated within
multiple basic environments that include various pH ranges, anions, and organic amines.
Recognition of the basic media by the chemosensors that have acidic NH and NH groups,
2
1
occurs via the deprotonation process which was supported with reversibility study and H
NMR experiments. The density functional theory calculations have employed to support the
experimental results. Chemosensors 6a and 6b showed remarkable detection ability in a pH
-
range of 7–11 and they have been also successfully utilized in the determination of CN in
semi-aqueous media.
2
2
2
2
0
1
2
3
Keywords: Colorimetric chemosensors, Azo dyes, pH sensors, Anions, Organic bases, DFT.
*Corresponding authors:
*E-mail addresses: baydiner@gazi.edu.tr (B. Aydıner), senoz@hacettepe.edu.tr (H. Şenöz)

2
1
2
1. Introduction
Luminescent chemosensors for detection of ions are highly valuable in many research fields
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
due to various neutral and ionic species find widespread use in physiology, medical
diagnostics, catalysis, and environmental chemistry [1-3]. A colorimetric chemosensor
transforms the action of binding to a specific analyte into a readable signal as a change in
color and absorption [4]. More importantly, chemosensors have enabled the study of
molecular interactions in a range of different media and interfaces. These fast and easily
observable responses make the sensors more significant as a research area to improve. When
the designs of the colorimetric sensors are examined, it is seen that they consist of two main
parts, generally, the receptor part and signaling unit (chromophore) that they are covalently
linked by π-bridges like vinyl, imine, azo, or aromatic rings [5-7]. Interaction of the guest-
host system is investigated under three main mechanisms as binding site, displacement and
chemodosimeter [8, 9]. Binding site mechanism is usually caused by hydrogen-bond
interactions and basic analytes are easily detectable with this approach [10]. Moreover, this
interaction can be reversible and sensors can be reusable.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
The anions are one of the most studied analytes due to their many important parts in
biological systems, the environment and industrial applications [3, 11]. Especially, fluoride
and cyanide are frequently studied anions due to their presence in biological systems and
environmental waste [9, 12]. Cyanide is a highly toxic anion that is waste in many industrial
processes. Therefore, the detection of this anion is very important for environmental concern,
especially in aqueous media [13]. Fluoride anion plays a vital role in physiological processes
and associated with nerve gases, the analysis of drinking water, and the refinement of uranium
used in nuclear weapons manufacture [14,15]. The usual method for this anions selectivity is

3
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
deprotonation process between a molecule that had an acidic proton (OH, NH) and anions
[16]. Optical chemosensors containing a chromophoric group have been known as powerful
tools for signalling fluoride and cyanide ions [17-20]. Other widespread pollutants in nature
are organic amines. Because of their extensive use in pharmaceutical industries and dye
manufacturing, it is necessary to develop new and effective sensors for these amines [21-28].
Recent studies show that generally developed sensors are sensitive to only one media [29].
Multifunctional chemosensors acting for multi-analyte sensing through different binding sites,
can provide excellent advantages of low-cost, real-time detection in real-world chemical and
biological samples. In our previous studies, we investigated a similar coumarin-thiophene
core that has receptor parts as Schiff base with hydroxyl groups, or amide group for their
anions selectivity, and indole bearing allylidenemalononitrile group for detection of cyanide
and nonlinear optic (NLO) properties of dyes [30-32]. In this study, we designed new
chemosensors bearing 7-diethylaminocoumarin-thiophene and 3-allylidenemalononitrile-
indole groups which conjugated by the azo bridge (Fig. 1). Dimethine group is an important
part of many functional dyes such as polymethine and cyanine dyes [33-36]. Azo dyes are one
of the most studied dye classes due to their wide range of color, and easily synthesized and
good dyeing performance [37, 38]. Moreover, functionalized azo dyes are used in optical
systems like NLO, dye-sensitized solar cells, etc. and sensor systems such as detection of
anions and cations [39-41]. Although dimethine and azo groups containing dyes were studied
by many researchers, there are not many compounds bearing both of these functional groups.
Our synthesized dyes showed that they can be a useful tool to determinate different basic
environmental changes such as cyanide in partial aqueous media, pH changes, and few
aliphatic amines.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
4

4
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
Fig. 1. Design of the chemosensors.
2. Experimental
2.1. Materials and instrumentation
All chemicals used were commercially available and no further purification was carried out.
Thin-layer chromatography (TLC) was used to monitor the reaction with pre-coated silica gel
1
13
60 F254 plates. NMR spectra were measured on Bruker Avance 300 ( H NMR: 300 MHz, C
1
13
NMR: 75 MHz) and Bruker Avance 400 ( H NMR: 400 MHz, C NMR: 100 MHz)
spectrometers at 20 ºC (293 K). Chemical shifts (δ) are given in parts per million (ppm) using
the residue solvent peaks as a reference relative to TMS. Coupling constants (J) are given in
hertz (Hz). Signals are abbreviated as follows: singlet. s; doublet. d; doublet-doublet. dd;
triplet. t; quartet. q; multiplet. m. High-resolution mass spectra (HR-MS) were recorded at the
Gazi University Faculty of Pharmacy using electron ionization (EI) mass spectrometry
Waters-LCT-Premier-XE-LTOF (TOF-MS) instruments in m/z (rel. %) and Bilkent
University National Nanotechnology Research Center using Agilent Technologies 6530
Accurate-Mass Q-TOF LC/MS. The microwave syntheses were carried out in a Milestone
Start microwave reaction system. The melting points were measured using Electrothermal
IA9200 apparatus. Absorption spectra were recorded on a Shimadzu 1800 spectrophotometer;
fluorescence spectra were recorded on a Hitachi F-7000 fluorescence spectrophotometer.
1
1
1
1
1
1
1
1
1
1
2
2

5
1
2
3
2.2. Synthesis
Synthesis of 3-acetyl-7-(diethylamino)-2H-chromen-2-one (1)
1 was synthesized according to the literature procedure [42].
°
°
1
4
5
6
Yield: 89 %; mp: 152-153 C (lit: 151-152 C), H NMR (300 MHz, DMSO-d δ ppm) 8.49
6,
(s, 1H), 7.67 (d, J=9.5 Hz, 1H), 6.80 (dd, J = 2.4 Hz, J = 2.0 Hz, 1H), 6.58 (d, J = 2.3 Hz,
1
2
1H), 3.50 (q, J = 7.0 Hz 4H), 2.50 (s, 3H), 1.14 (t, J = 7.0 Hz, 6H).
7
8
9
0
1
2
Synthesis of 2-(1-(7-(diethylamino)-2-oxo-2H-chromen-3-yl)ethylidene)malononitrile (2)
2 was synthesized according to the literature procedure [42].
°
°
1
1
1
1
Yield: 75 %; mp: 145-146 C (lit: 145-146 C), H NMR (300 MHz, DMSO-d δ ppm) 8.33
6,
(s, 1H), 7.56 (d, J = 9.0 Hz, 1H), 6.83 (dd, J = 2.3 Hz, J = 2.3 Hz, 1H), 6.63 (d, J = 2.1 Hz
1
2
1H), 3.50 (q, J = 6.95 Hz, 4H), 2.55 (s, 3H), 1.15 (t, J = 7.0 Hz, 6H).
1
1
1
1
1
1
3
4
5
6
7
8
Synthesis of 2-amino-4-(7-(diethylamino)-2-oxo-2H-chromen-3-yl)thiophene-3-carbonitrile
(3):
3 was synthesized according to the literature procedure [42].
°
°
1
Yield: 92 %; mp: 211-212 C (lit: 211-213 C), H NMR (300 MHz, DMSO-d δ ppm) 7.98
6
,
(s, 1H), 7.48 (d, J = 8.9 Hz, 1H), 7.20 (s, 2H), 6.73 (dd, J = 2.4 Hz, J = 2.4 Hz, 1H), 6.66 (s,
1
2
1H), 6.56 (d, J = 2.2 Hz, 1H), 3.45 (q, J = 7.69 Hz, 4H), 1.10 (t, J = 7.58 Hz, 6H).
1
2
2
9
0
1
Synthesis of 2-(1-(4-aminophenyl)ethylidene)malononitrile (4)
4 was synthesized according to the literature procedure [43].
°
°
1
1
2
2
2
2
3
4
Yield: 80 %; mp: 185-186 C (lit: 185 C), H-NMR (300 MHz, CDCl ) δ H NMR (300
3
MHz, DMSO-d δ ppm) 7.58 (d, J = 8.8 Hz, 2H), 6.62 (d, J = 8.8 Hz, 2H), 6.43 (s, 2H), 2.51
6
,
(s, 3H).
2
2
2
5
6
7
Synthesis of (E)-2-(1-(4-aminophenyl)-3-(1H-indol-3-yl)allylidene)malononitrile (5a)
5a was synthesized according to the literature procedure [44].
°
°
1
2
2
8
9
Yield: 60 %; mp: 248-249 C (lit: 247-249 C), H NMR (300 MHz, DMSO-d δ ppm) 8.10
6,
(s, 1H), 7.90 (dd, 1H), 7.60 (dd, 1H), 7.36 (m, 7H), 6.71 (d, J = 8.6 Hz, 2H), 6.10 (s, 2H).

6
1
2
3
Synthesis of (E)-2-(1-(4-aminophenyl)-3-(1-methyl-1H-indol-3-yl)allylidene)malononitrile
(5b)
4
5
6
5b was synthesized according to the literature procedure [44].
°
°
1
Yield: 50 %; mp: 254-255 C (lit: 254-256 C), H NMR (300 MHz, DMSO-d δ ppm) 8.10
6
,
(s, 1H), 7.85 (dd, 1H), 7.60 (dd, 1H), 7.36 (m, 6H), 6.71 (d, J = 8.6 Hz, 2H), 6.10 (s, 2H).
7
8
General Synthesis of The Dyes (6a-6b).
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
3 (1.0 mmol) was dissolved in hydrochloric acid (1.0 mL of conc. HCl in 2.0 mL of water)
and the solution cooled to (-5)-0 °C. Sodium nitrite solution (c = 0.5 M in water) was slowly
added to the mixture. After 1 hour of stirring, urea (a small amount) was added to remove
excess nitrous acid and used immediately for the coupling reaction. 5a / 5b (1.0 mmol) was
dissolved in acetic acid/propionic acid (6 mL, 4:2, v/v) and cooled to (-5)-0 °C and the
diazonium salt solution was slowly added to the mixture of 3 while stirring. After 1 hour,
conc. sodium carbonate solution was added to the mixture till pH 5-6. The mixture was stirred
for an additional 1 hour at (-5)-0 °C. After 1 hour, water was added to the mixture and the
precipitate was filtered, washed with cold water, dried and recrystallized with ethanol to
obtain pure compounds.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
Synthesis
of
2-((2E)-1-(4-((5-amino-4-cyano-3-(7-(diethylamino)-2-oxo-2H-chromen-3-
yl)thiophen-2-yl)diazenyl)phenyl)-3-(1H-indol-3-yl)allylidene)malononitrile (6a):
°
-1
Yield: 78 %, mp: 249-250 C, FT-IR (KBr, cm ): 3412, 3292, 3178, 2971, 2212, 1709,
1
1677.87, 1636, 1615, 1586, 1570, 1525, 1494, 1467, 1418, 1350, 1316, 1258. H NMR (400
MHz, DMSO-d δ ppm) 12.28 (s, 1H), 8.76 (s, 2H), 8.21 (s, 1H), 8.11 (s, 1H), 7.83 (d, J = 5.5
6
,
Hz, 1H), 7.72 (d, J = 8.0 Hz, 2H), 7.58 (t, J = 10.1 Hz, 3H), 7.52 (d, J = 5.0 Hz, 1H), 7.45 (d,
J = 15.3 Hz, 1H), 7.30 (d, J = 2.9 Hz, 2H), 7.24 (d, J = 15.2 Hz, 1H), 6.77 (d, J = 8.6 Hz, 1H),
1
3
6.62 (s, 1H), 3.46 (d, J = 6.0 Hz, 4H), 1.13 (t, J = 6.1 Hz, 6H). C NMR (100 MHz, DMSO-
d δ ppm) 171.4, 167.7, 158.9, 156.6, 153.3, 151.5, 146.8, 145.0, 143.4, 138.1, 138.0, 137.2,
6
,
133.5, 130.5, 130.5, 124.4, 123.7, 122.4, 121.8, 119.9, 117.6, 115.1, 114.6, 114.5, 114.1,
113.3, 110.7, 109.7, 107.6, 96.3, 88.6, 73.4, 44.3, 12.4. HRMS m/z calculated for
+
C H N O SNa: 683.1948, found 683.2005 (M-Na) .
38
28
8
2

7
1
2
3
4
5
6
7
8
9
0
1
2
Synthesis
of
2-((2E)-1-(4-((5-amino-4-cyano-3-(7-(diethylamino)-2-oxo-2H-chromen-3-
yl)thiophen-2-yl)diazenyl)phenyl)-3-(1-methyl-1H-indol-3-yl)allylidene)malononitrile (6b):
°
-1
Red solid; Yield: 45 %; mp: 329-330 C; FT-IR (KBr, ν , cm ): 3291, 3178, 2972, 2213,
maks
1
1679, 1248. H NMR (400 MHz, DMSO-d δ ppm) 8.76 (s, 2H), 8.21 (s, 1H), 8.12 (s, 1H),
6
,
7.81 (d, J = 6.6 Hz, 1H), 7.71 (d, J = 7.9 Hz, 2H), 7.64 – 7.52 (m, J = 15.4, 8.1 Hz, 4H), 7.42
(d, J = 15.3 Hz, 1H), 7.35 (s, 2H), 7.18 (d, J = 15.2 Hz, 1H), 6.77 (d, J = 8.6 Hz, 1H), 6.62 (s,
13
1H), 3.82 (s, 3H), 3.47 (d, J = 6.6 Hz, 4H), 1.14 (t, J = 6.5 Hz, 6H). C NMR (100 MHz,
DMSO-d δ ppm) 171.1, 167.6, 158.8, 156.5, 153.2, 151.4, 146.7, 144.1, 138.4, 138, 133.4,
6
,
1
1
1
130.4, 125, 123.6, 122.6, 121.7, 119.8, 117.4, 115.1, 114.5, 113.0, 111.7, 110.6, 109.5, 107.5,
96.3, 88.5, 73.2, 44.2, 33.4, 12.3. HRMS m/z calculated for C H N O S: 675.2291, found
3
9
31
8
2
+
675.2307 (M-H) .
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
2.4. Photophysical properties of the dyes
The dyes (10 µM for absorption and fluorescence emission), were studied in five solvents
with different polarities (THF, DCM, DMSO, Diox, and ACN).
2.5. Anion Selectivity Study
The UV-vis and fluorometric spectra were recorded in order to study the selectivity of various
-
-
-
-
-
-
anions as their tetrabutylammonium (TBA) salts (TBAX where X=F , I , Cl , Br , AcO , CN ,
-
-
-
-
H PO , NO , ClO and HSO ) towards the compound 6a-b. The dyes 6a and 6b were
2
4
3
4
4
titrated with studied anions by UV-Vis absorption spectra in DMSO/water 9/1 (v/v) and the
8/2 (v/v) binary mixture, respectively.
1
2.6. H NMR titration study
Spectra were recorded first on the dye 6a (10 mM), followed by the addition of aliquots of a
-
-
solution of anions as TBA salts, F and CN , (1 M) in DMSO-d .
6

8
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
2.7. Computational methods
The ground state geometries of the compounds and their complexes were obtained by
performing the density functional theory (DFT) calculations in the Gaussian 09 program
package [45]. The confirmation of the convergence to minima on the potential energy surface
was made from the vibrational analysis for each compound. The absorption spectra were
obtained within time-dependent DFT (TD-DFT) calculations using the PCM model [46,47].
The natural charges were estimated from Natural Bond Orbital calculations in DMSO. All
calculations were carried out using B3LYP functional with 6-31g(d,p) basis set [48-50].
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
3. Results and discussion
3.1. Design and synthesis of the sensors
The chemosensors (6a and 6b) which are the coumarin-thiophene-indole conjugated by diazo
and methylene bridges were synthesized. In this molecule design, we aimed to investigate the
effect of the multiple heterocyclic (coumarin, thiophene, and indole) and chromophore groups
(methylene and diazo) in the same system. 7-diethylaminocoumarin derivatives are good
fluorescent dyes that have tunable properties from the blue to near-infrared (NIR) region by
changing the electron acceptor at usually 3-position of the coumarin [29,30]. The synthesis
route of the dyes (6a-b) is depicted in Scheme 1. Coumarin-thiophene intermediate (3) was
synthesized by the method that our group previously was improved by three-step reactions
with good yield (92 %) [42]. Indole/N-methylindole and phenyl conjugated by
allylidenemalononitrile moiety (5a and 5b) were synthesized by Knoevenagel condensation
reaction with moderate yield (60 % and 50 %, respectively). The chemosensors were
synthesized by the reaction between coumarin intermediated (3) and compound 5a/5b that

9
1
2
3
were prepared as a diazonium salt. The chemosensors were obtained with good to moderate
yields as 78 % (6a) and 45 % (6b).
4
5
Scheme 1. Synthetic pathway of the dyes.
6
7
8
9
0
1
2
3
4
5
6
7
3.2. Photophysical properties
Absorption and emission spectra of the dyes were investigated in solvents with different
polarities at room temperature. The absorption coefficients (ε) were calculated according to
-1
-1
-1
-1
1
1
1
1
1
1
1
1
the Beer-Lambert Law and found 56800-68000 M .cm for 6a and 45800-59800 M .cm for
6b. As can be seen from Table 1, absorption and emission maxima of the dyes were showed
correlation with the increase in solvent polarity except acetonitrile (Figs. 2 and 3). Absorption
maxima of 6a and 6b were found between 437-467 nm and 452-473 nm, respectively, and
emission maxima ranging from 477-552 for both dyes. Changing indole NH hydrogen with
methyl group shifted absorption maxima to the bathochromic region about 6-15 nm. A
similar result was obtained at our previous study that (4-aminophenyl)-
allylidenemalononitrile-3-indole molecules with NH and N-methyl parts was investigated and

1
0
1
2
3
4
5
6
7
found that adding the methyl group to indole nitrogen changed the absorption maxima to
slightly to bathochromic region due to methyl group have more electron donor properties
compared to free NH [43]. Stokes shifts were calculated from the difference between
-1
wavenumber of absorption and emission maxima and found between 2079 and 3343 cm for
-1
6a and 1061 and 3252 cm for 6b.
Table 1. Photophysical properties of the 6a-b (c = 10 µM) in different solvents.
a
b
c
-1
-1
-1
Dyes
Solvents
λabs(nm)
λfl(nm)
Stokes Shiff (cm )
ε (M .cm )
DiOX
THF
437
448
461
467
443
452
458
468
473
458
479
494
534
552
494
477
513
552
498
530
2006
2079
2965
3343
2330
1160
2341
3252
1061
2966
68004
60916
68904
65395
56800
59870
45898
48991
59125
47413
6
a
DMF
DMSO
ACN
DiOX
THF
6
b
DMF
DMSO
ACN
a
b
c
8
9
Long wavelength absorption maximum, in nm; c = 10 μM. Fluorescence maximum, in nm; c = 10 μM. ε = molar absorption coefficient
-1 -1
(cm M ).
1
1
1
1
1
1
1
0
1
2
3
4
5
6
6a that has an NH group exhibited yellow color under daylight except for DMSO that was
brown and was emitted from blue to green under UV-light (Fig. 2-inset). 6b that has the
methyl group at the nitrogen of indole exhibited orange color under daylight and also showed
very low orange emission under UV light (Fig. 3-inset).

1
1
1
2
3
4
Fig. 2. The normalized absorption (a) and normalized emission (b) spectra of 6a (c = 10 μM)
in different polarity solvents. Insets: Photographs of 6a (c = 25 µM) in different polarity
solvents under ambient light (a) and UV light (b).
5
6
7
8
9
0
Fig. 3. The normalized absorption (a) and normalized emission (b) spectra of 6b (c = 10 μM)
in different polarity solvents. Insets: Photographs of 6b (c = 25 µM) in different polarity
solvents under ambient light (a) and UV light (b).
1
1
1
2
3
4
5
6
7
8
3.3. Spectrophotometric and spectrofluorometric titrations of the dyes with various anions
1
1
1
1
1
1
1
The sensing ability of the dyes were investigated by using spectrophotometric titration
-
-
-
-
-
-
-
-
-
-
methods and the dyes were titrated F , Cl , Br , I , AcO , CN , OH , NO , ClO , HSO and
3
4
4
-
H PO with tetrabutylammonium (TBA) salts as the counter cation. Fig. 4 shows that change
2
4
in absorption spectra of 6a and 6b (10 μM) measured in DMSO with respective anions as a n-
+
Bu N salt (20 equiv.). The absorption spectra of these two dyes in DMSO showed a strong
4
-
-
band centered around 470 nm. After the addition of various anions to the dyes, only F , AcO ,
-
-
-
CN , OH , and H PO were showed a significant change. Upon addition of these anions to 6a,
2
4

1
2
1
2
3
4
5
6
7
8
9
the absorption band of the dye decreased and showed two bands at 440 and 475 nm.
Moreover, the new two bands formed with one of them at 527 nm and the other one as
broadband at 610-620 nm (Table 2). 6b showed different shifts at absorption spectra after
addition the same anions, band at 472 nm gave only bathochromic shifts to 660-670 nm. 6a
has two acidic parts, one of them is indole NH attaching allylidenemalononitrile at 3-position
of the indole ring, the second one is amino group attaching thiophene moiety while 6b has an
only amino group as acidic part. These results show that the band formed at a longer
wavelength (660-670 nm) is caused by deprotonation of the amino group, while the other new
band at 527 nm was formed after the deprotonation of indole NH (Scheme 2).
1
0
1
1
1
1
1
1
2
3
4
5
Fig. 4. UV-vis titration spectra titration spectra of 6a (a) and 6b (b) (c = 10 μM in DMSO)
with different anion 20 equiv. in DMSO. Insets: Photographs of 6a and 6b (c = 25 μM in
DMSO) after addition of 20 equiv. of various anions (c = 1.0 M in DMSO) under ambient
light.
1
6

1
3
1
2
Scheme 2. The possible anion sensing mechanism of 6a.
3
4
5
6
7
8
9
0
1
2
To understand the sensing mechanism between the dyes and anions, titration study were
1
-
-
-
conducted with H NMR method (Fig. 5). Upon addition of 2 equiv. of F , CN , AcO to 6a,
NH and NH signals at 12.39 and 8.77 ppm were disappeared and a slight upper field shift of
2
the signals were observed due to the incensement of electron density in the conjugated
-
-
-
system. After addition of F , CN , AcO , Ha signal at 8.12 ppm, 3-position of indole, shifted to
7.79, 7.68, and 7.88 ppm while Hb signal at 8.22 ppm, 4-position of coumarin, was shifted to
8.06, 8.03, and 8.09, respectively. The most significant change was observed after the
addition of cyanide.
1
1
1

1
4
1
1
2
3
Fig. 5. H-NMR spectral change of 6a (10ꢀmM) in the absence (a) and presence of 2 equiv. of
TBACN (b), TBAF (c) and TBAAcO (d) in DMSO-d6.
4
5
6
7
8
9
0
1
2
3
The colorimetric sensitivity of the dyes (6a-b) was investigated in DMSO with studies anions.
-
-
-
As depicted in Fig. 5, upon the addition of F , CN , and OH , significant color changes were
-
observed in the solution of 6a in DMSO from orange to purple, and light brown with AcO
while distinctive color changes were observed solution of 6a in ACN from orange to purple
-
-
-
-
-
with F , CN , and OH , and green with AcO and H PO (Fig. 6). Furthermore, 6a showed
2
4
-
-
-
1
1
1
1
fluorescence quenching when interacted with F , CN , and OH in ACN while 6a did not have
significant emission under UV-light in DMSO. Meanwhile, 6b was given less selective color
-
-
-
-
-
changes from orange to green upon the addition of F , AcO , CN , OH , and H PO in both
2
4
DMSO and ACN (Fig. 5 and Fig. S38).
1
4

1
5
1
2
3
Fig. 6. Photographs of 6a (c = 25 μM in ACN) after addition of 20 equiv. of studied anions
under ambient light (a) and under UV light (b).
4
5
Table 2. The shift values of absorption maxima upon addition anions in DMSO for 6a-6b.
λabsmax (nm)
Dyes
Anions
(
after addition of 20 equiv. of anions)
-
F
4
4
38, 527, 608
72, 527, 621
-
AcO
6
a
-
4
4
40, 480, 527, 608
467, 659
CN
(
λabsmax = 466nm)
-
H PO4
2
-
41, 475, 527, 610
OH
-
F
4
4
4
63, 660
60, 670
58, 670
-
AcO
6
b
-
CN
(
λabsmax = 472 nm)
-
H PO4
463, 671
65, 660
2
-
4
OH
6
7
8
9
0
1
2
3.4. Reversibility
The reversibility of chemosensors is a very important feature for the applications in the real
environment. The determination of the reversibility of dyes was investigated by absorption
1
1
1
-
-
spectroscopy and colorimetric changes. Upon addition of 20 equiv. of anions (only F , AcO ,
-
-
-
CN , OH , and H PO ) to the solution of 6a and 6b, absorption maxima of the dyes were
2
4

1
6
1
2
3
4
5
6
7
8
shifted to bathochromic region. After 20 equiv. of trifluoroacetic acid (TFA) was added to the
mixture, absorption maxima of dyes were shifted hypsochromicly to original maxima of the
dyes (Fig.7 and Fig. S39-S46). Moreover, colorimetric changes of the dyes 6a and 6b were
restored from purple and green to orange, respectively. This reversibility of dyes was also
indicated that only the deprotonation mechanism occurred although there was a possibility of
cyanide that can behave as nucleophile as well as base and could give addition reaction to
methylene bridges.
9
-
1
1
1
1
0
1
2
3
Fig. 7. UV-vis spectra of 6a (a) and 6b (b) (c = 10 µM) after addition of CN and its
reversibility control using TFA acid (c = 1.0 M in DMSO) in DMSO. Insert: Photographs of
6a and 6b (c=25 µM in DMSO) upon the addition of 20 equiv. of CN and TFA under ambient
-
light.
1
1
4
5
3.5. Anion interaction in the partial aqueous medium for selectivity
1
1
1
1
2
2
2
6
7
8
9
0
1
2
To demonstrate the potential application of the chemosensors, the titration studies also were
done in the partial aqueous medium. Absorption spectra of the dyes 6a-6b in different
mixtures of water and DMSO were taken after the addition of 50 equiv. of TBACN (Fig. S47-
55) and the best ratio of DMSO:water was decided as 9:1 (v/v) and 8:2 (v/v), respectively.
-
-
-
-
Titration experiments were carried out by stepwise addition of CN , F , OH , AcO , and
-
-
H PO to the dyes and can be seen from Fig. 8. The results showed only CN responded
2
4
towards 6a and 6b in the binary aqueous medium. Similar to titration studies in DMSO, upon

1
7
1
2
3
4
5
6
7
8
9
0
1
2
3
addition of cyanide to 6a, absorption maxima at 463 nm was shifted to the bathochromic
-
-
region at 526 nm and two weak bands at 415 and 640 nm were formed. Even though F , OH ,
-
-
AcO , and H PO interacted with the dyes in DMSO, they did not show any change in the
2
4
binary mixture. These results can explain that the hydrogen bonding affinity of anions
changed as the same titration experiment is carried out in an aqueous medium. A factor
-
contributing to this selectivity of cyanide is the high hydration enthalpy(ΔH ) of F (-504
hyd
-
-
-
kJ/mol), OH (- 403 kJ/mol), AcO (-375 kJ/mol ) and H PO (-260 kJ/mol). Compared the
2
4
other anions, cyanide has low hydration energy (-67 kJ/mol ) [51-55]. Moreover, reversibility
test of dyes in aqueous media were done to established that deprotonation is still main
interaction mechanism. Upon addition of 20 equiv. of cyanide to the dyes, bathochromic
shifts were observed. Then, 20 equiv. of TFA was added to the mixture, and hypochromic
shifts were occurred and absorption maxima shifted to original maxima of the dyes (Fig S56).
1
1
1
1
1
4
1
1
1
1
5
6
7
8
Fig. 8. UV-vis titration spectra of 6a (a) and 6b (b) (c =10 μM) with different 20 equiv. of
TBA salts in DMSO:water 9:1 (v/v) and 8:2 (v/v), respectively. Insert: Photographs of 6a and
6b (c=25 μM in DMSO:water) after addition of 20 equiv. of studied anions under ambient
light.
1
2
2
9
0
1
After established that 6a and 6b are showed selectivity to cyanide in aqueous solution by
using distilled water, it was decided to investigate the performance of the dyes in tap water as

1
8
1
2
3
4
5
the real sample. In this investigation, KCN was used instead of TBACN and absorption
titration experiments were carried out. The results showed that similar to distilled water
experiments, new absorption bands were appeared at 527 and 618 nm for 6a and 634 nm for
6b (Fig. 9). Moreover, distinctive colorimetric changes for 6a and 6b were observed from
orange to red-brown and green, respectively (Fig. 9-inset).
6
7
8
Fꢀg. 9. UV-Vꢁs tꢁtratꢁon spectra of 6a (a) and 6b (b) (c = 10 μM ꢁn DMS O) wꢁth 20 equiv. of
KCN ꢁn DMS O:Tap water mꢁxture 9:1 (v/v) and 8:2 (v/v), respectively. Insert: Photographs of
6a and 6b (c = 25 µM in DMSO:Tap water) after the addition of 20 equiv. of CN under
9
0
1
2
-
1
1
1
ambient light in DMSO:Tap water mixture.
1
1
3
4
3.6. pH-dependent study
In order to understand the effect of the basic environment to the dyes, the chemosensors were
1
1
1
1
1
2
2
5
6
7
8
9
0
1
also studied in mixtures of DMSO and buffer solution. The pH-dependent spectral
characteristics of the dyes (10 μM) were evaluated in a Britton Robinson buffer solution that
pH values ranged between 7.0-11.0, with DMSO as a co-solvent (Fig. 10). Absorption spectra
of 6a showed that only at pH 11.0, a new band began to form at 515 nm. But photographs of
6a showed a significant color changed when the pH of media change from 8.0 to 8.5, the
absorption color of the dye changed from orange to purple (Fig. 10a-inset). pH-dependent
study of 6b gave more sensitive response at absorption spectra compared to 6a when pH

1
9
1
2
3
4
media changed to 8.5 from 8.0, a new band at 630 nm and absorbance of the band increased at
higher pH (Fig. 10b). Colorimetric changes were similar to 6a, absorbance color was changed
to green from orange when pH increased from 8.0 to 8.5.
5
6
7
8
9
Fig. 10. UV-vis spectra of 6a (a) and 6b (b) (c = 10 μM) different pH values in DMSO:Buffer
7:3 (v/v). Inset: Photographs of 6a (a) and 6b (b) (c = 25 μM in DMSO:Buffer 7:3) dꢁfferent
pH value.
1
1
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
8
9
3.7. Sensitivity Study of Organic Amines
Amines are widespread pollutants in nature and detection of them has become of large interest
since they used extensively in pharmaceutical industries and dye manufacturing [22].
Therefore, we also studied various amines for their detection. Seven different amines were
investigated and only three of them which are secondary aliphatic amines were interacted with
6a and 6b (Fig. 11 and S57-62). As depicted in Fig. 11, upon addition of various amines to
6a, piperidine, pyrrolidine, and diethylamine gave response as a new band at 653-658 nm and
shoulder at 519 nm. Furthermore, colorimetric changes were observed with naked eye-
detection that the orange color of the chemosensor was changed to green under ambient-light.
Interestingly, these three amines when were added to 6b gave a new band at 658-675 nm with

2
0
1
2
3
4
5
6
7
8
9
0
low absorbance but there were not any significant changes observed at the absorption color of
the dye (Fig. 11b). Basicity is the primary factor in determining interaction with the
chemosensors but also other factors are interfering with the interaction as steric and
conformational effects, resonance, and induction. Piperidine (11.12), pyrrolidine (11.31) and
diethylamine (10.84) have high pK values that they are more basic properties than
a
diphenylamine (0.79) and triphenylamine (not considered as a base). Interestingly, pK of
a
trimethylamine is 10.75 that is close value to interacted three amines. But no changes
observed when trimethylamine was added to the dyes due to steric hindrance. Also, pyridine
that is an aromatic amine with low pK (5.23) did not give any spectral change.
a
1
1
1
1
1
1
1
2
3
4
5
Fig. 11. UV-vis titration of 6a (a) and 6b (b) (c = 10 μM in DMSO) with 200 equiv. of
different organic bases in DMSO. Inset: Photographs of the dyes 6a (a) and 6b (b) (c = 2.5
μM in DMSO) after addition of 200 equiv. of studies amine bases (c = 1.0 M in DMSO) under
ambient light.
1
1
1
6
7
8
3.8. LOD of the dyes towards sensing of cyanide and aromatic amines
−
The limit of detection (LOD) of CN in DMSO and aqueous media were calculated on the
1
2
9
0
basis of the equations; LOD=3δ/S, where δ is the standard deviation of the response and S is
−
the slope of the absorpiton calibration curve of CN and the results are represented in Figs.

2
1
1
2
3
4
5
6
7
8
S63-68 of the Supporting Information. 6a showed the detection of cyanide with LODs of 7.9
μM in DMSO, 19 μM in DMSO/water (9:1, v/v) mixture, and 0.40 mM in DMSO/tap water
(9:1, v/v) mixture. Meanwhile, 6b showed the detection of cyanide with LODs of 2.2 μM in
DMSO, 5.6 μM in DMSO/water (9:1, v/v) mixture, and 26 μM in DMSO/tap water (9:1, v/v)
mixture. Consequently, 6b is more sensitive for cyanide in tap water media comparing to 6a.
Moreover, the same calculations were done for the dyes with titration of piperidine,
pyrrolidine, and diethylamine in DMSO and calculated as 0.09 mM, 0.57 mM, and 0.2 mM
for 6a, and 0.50 mM, 1.2 mM, and 1.8 mM for 6b, respectively (Fig. S69-74.)
9
0
1
3.9. Theoretical Results
-
-
-
1
1
1
1
1
1
1
1
1
1
2
3
4
5
6
7
8
9
The structures of 6a, 6b and their anionic structures formed by interactions with F , CN , OH ,
-
-
AcO and H PO anions within the framework of density functional theory (DFT)
2
4
calculations at B3LYP/631g(d,p) level in the gas phase. The optimized structures and
geometry parameters are illustrated in Fig. 12, Fig. S75 and Table S3, with the atomic
numbering in Fig. S76. The optimized structures clearly showed that the indole –NH and
NH…H (in the –NH group attaching thiophene moiety) bond distances increase after the
2
-
-
-
-
-
interaction 6a with F , CN , OH and AcO via di-deprotonation process, for H PO
2
4
interactions, the anion deprotonated the indole –NH exactly and interacted with –NH group
2
(Fig. 12, Table S3).
2
0

2
2
1
-
-
-
2
3
Fꢀg. 12. The optꢁmꢁzed structures of 6a and theꢁr complexes 6a+F , 6a+CN , 6a+OH ,
-
4-
6a+AcO , 6a+H PO and change ꢁn the negatꢁve charges on selected atoms.
2
4
-
-
-
-
5
6
7
8
9
0
1
2
3
4
5
6
The change in the natural charges on some atoms for 6a+F , 6a+CN , 6a+OH , 6a+AcO and
-
6a+H PO with respect to 6a in DMSO after the interactions with related anions were also
2
4
shown in Fig. 12 and Table S4. The natural charges on given atoms increase after interactions
and as expected, these changing will reflect absorption spectra. To see the effects of these
expectations, the absorption spectra were calculated within TD-DFT calculations in DMSO.
The absorption maxima, oscillator strengths and corresponding transitions with their
contributions were listed in Table S5. The absorption maxima of 6a was observed at 497 nm
1
1
1
1
1
1
1
-
with f = 0.516 and the major contributions of H-1→L and H-2→L transitions. For 6a+F ,
-
-
-
6a+CN , 6a+OH and 6a+AcO , the absorption maxima shifted to 435-438 nm and there was
-
a new peak at 578-584 nm. For 6a+H PO , the shifted in absorption maxima at 492 nm was
2
4
negligible and only the occurring new peak at 565 nm was seen, which can be attributed to the
fact that the dihydrogen phosphate ion deprotonated indole –NH proton and interacted with –

2
3
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
NH proton weakly. The calculated results were in good agreement with experimental ones
2
(Table 2).
In case of 6b, the deprotonation process was possible between -NH proton and anions (Fig.
2
S75) the increased negative charges on amine nitrogen (N43) after the deprotonation of -NH2
proton are distributed to both of the nitrogen of cyano (C46 ≡ N47) and azo bridge through
thiophene and dicyano group through phenyl (Fig. S76 and Table S6). The absorption
maxima seen at 472 nm for 6b, shifted to a lower wavelength at about 464-468 nm and a new
-
-
-
-
peak at the higher wavelength at about 595-653 nm for 6b+F , 6b+CN , 6b+OH , 6b+AcO
-
and 6a+H PO (Table S5), which were consistent with experimental results.
2
4
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
4. Conclusions
Multifunctional colorimetric chemosensors were designed and synthesized within mild
-
-
-
-
conditions and moderate to good yields. The dyes are sensitive to F , AcO , CN , OH , and
-
H PO in DMSO compared to other studies anions while both of the dyes are selective to
2
4
-
only CN in partial aqueous solution. Furthemore, the change of pH from 8.0 to 8.5 can be
easily determined by the dyes with colorimetrically. Moreover, 6a can be sense
colorimetrically some of the organic amines that are piperidine, pyrrolidine, and diethylamine.
The proposed sensing mechanisms as deprotonation of amino groups were supported by the
theoretical calculations, which were compatible with experimental results. The results showed
that the dyes can be used as novel colorimetric chemosensors as multimedia basic sensors.
Acknowledgments
All the authors are appreciative of the Scientific and Technological Research Council of
Turkey (TUBITAK) (Grant no. 117Z582) for the financial support for carrying out this work.

2
4
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
The numerical calculations reported in this paper were fully performed at TUBITAK
ULAKBIM, High Performance and Grid Computing Center (TRUBA resources).
References
[1]
Approaches. Chem Rev 2020;120:1888–935. https://doi.org/10.1021/acs.chemrev.9b00624
[2] Beer PD, Gale PA. Anion recognition and sensing: The state of the art and future
perspectives. Angew Chemie - Int Ed 2001;40:486–516. https://doi.org/10.1002/1521-
3773(20010202)40:3<486::AID-ANIE486>3.0.CO;2-P
[3] Geddes CD. Optical halide sensing using fluorescence quenching: theory, simulations
and applications - a review. Meas Sci Technol 2001;12:R53–88. https://doi.org/10.1088/0957-
0233/12/9/201
[4] Sedgwick AC, James TD. Virtual Issue: Chemosensors. ChemistryOpen 2018;7:215–
6. https://doi.org/10.1002/open.201800027
[5] Upadhyay S, Singh A, Sinha R, Omer S, Negi K. Colorimetric chemosensors for d-
metal ions: A review in the past, present and future prospect. J Mol Struct 2019;1193:89–102.
https://doi.org/10.1016/j.molstruc.2019.05.007
[6] Martínez-Máñez R, Sancenón F. Fluorogenic and chromogenic chemosensors and
reagents for anions. vol. 103. 2003. https://doi.org/10.1021/cr010421e
[7] Xu Z, Chen X, Kim HN, Yoon J. Sensors for the optical detection of cyanide ion.
Chem Soc Rev 2010;39:127–37. https://doi.org/10.1039/b907368j
[8] Molina P, Zapata F, Caballero A. Anion Recognition Strategies Based on Combined
Noncovalent Interactions. Chem Rev 2017;117:9907–72.
https://doi.org/10.1021/acs.chemrev.6b00814
Hein R, Beer PD, Davis JJ. Electrochemical Anion Sensing: Supramolecular
.
.
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
.
.
.
.
.
.

2
5
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
[9]
Gale PA, Caltagirone C. Fluorescent and colorimetric sensors for anionic species.
Coord Chem Rev 2018;354:2–27. https://doi.org/10.1016/j.ccr.2017.05.003
.
[10] Sessler, J. L., Gale, P. A., & Cho, W. S. (2006). Anion receptor chemistry (Vol. 8).
Royal Society of Chemistry.
[11] John Y, David VE, Mmereki D. A Comparative Study on Removal of Hazardous
Anions from Water by Adsorption: A Review. Int J Chem Eng 2018;2018:1–21.
https://doi.org/10.1155/2018/3975948
.
[12] Donato DB, Nichols O, Possingham H, Moore M, Ricci PF, Noller BN. A critical
review of the effects of gold cyanide-bearing tailings solutions on wildlife. Environ Int
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2007;33:974–84. https://doi.org/10.1016/j.envint.2007.04.007.
[13] Jaszczak E, Polkowska Ż, Narkowicz S, Namieśnik J. Cyanides in the environment—
analysis—problems and challenges. Environ Sci Pollut Res Int., 2017; 24(19):15929-15948.
https://doi.org/10.1007/s11356-017-9081-7.
[14] Huang YC, Chen CP, Wu PJ, Kuo SY, Chan YH. Coumarin dye-embedded
semiconducting polymer dots for ratiometric sensing of fluoride ions in aqueous solution and
bio-imaging in cells. J Mater Chem B 2014;2:6188–91. https://doi.org/10.1039/c4tb01026d
[15] Qu Y, Hua J, Tian H. Colorimetric and ratiometric red fluorescent chemosensor for
fluoride ion based on diketopyrrolopyrrole. Org Lett 2010;12:3320–3.
https://doi.org/10.1021/ol101081m
.
.
[16] Chung YM, Raman B, Kim DS, Ahn KH. Fluorescence modulation in anion sensing
by introducing intramolecular H-bonding interactions in host-guest adducts. Chem Commun
2006:186–8. https://doi.org/10.1039/b510795d
[17] Yahaya I. Fluorescence Dyes for Determination of Cyanide. In: Mondal ZSE-SSE-S,
editor., Rijeka: IntechOpen; 2018, p. Ch. 10. https://doi.org/10.5772/intechopen.75090
.
.

2
6
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
[18] Manivannan R, Satheshkumar A, El-Mossalamy ESH, Al-Harbi LM, Kosa SA, Elango
KP. Design, synthesis and characterization of indole based anion sensing receptors. New J
Chem 2015;39:3936–47. https://doi.org/10.1039/c4nj01728e
.
[19] Şahin Ö, Özdemir ÜÖ, Seferoğlu N, Aydıner B, Sarı M, Tunç T, et al. A highly
selective and sensitive chemosensor derived coumarin–thiazole for colorimetric and
fluorimetric detection of CN−ion in DMSO and aqueous solution: synthesis, sensing ability,
Pd(II)/Pt(II) complexes and theoretical studies. Tetrahedron 2016;72:5843–52.
https://doi.org/10.1016/j.tet.2016.08.004
.
[20] Udhayakumari D. Detection of toxic fluoride ion via chromogenic and fluorogenic
sensing. A comprehensive review of the year 2015–2019. Spectrochim Acta - Part A Mol
1
1
1
1
1
1
1
1
1
1
2
2
2
2
Biomol Spectrosc 2020;228:117817. https://doi.org/10.1016/j.saa.2019.117817
[21] Ge X, Wexler AS, Clegg SL. Atmospheric amines - Part I. A review. Atmos Environ
2011;45:524–46. https://doi.org/10.1016/j.atmosenv.2010.10.012
.
.
[22] Danchuk AI, Komova NS, Mobarez SN, Doronin SY, Burmistrova NA, Markin A V.,
et al. Optical sensors for determination of biogenic amines in food. Anal Bioanal Chem
2020:4023–36. https://doi.org/10.1007/s00216-020-02675-9
[23] Lu G, Grossman JE, Lambert JB. General but discriminating fluorescent chemosensor
for aliphatic amines. J Org Chem 2006;71:1769–76. https://doi.org/10.1021/jo0518405
[24] Reinert S, Mohr GJ. Chemosensor for the optical detection of aliphatic amines and
diamines. Chem Commun 2008:2272–4. https://doi.org/10.1039/b717796h
.
.
.
[25] Nawaz H, Zhang J, Tian W, Jin K, Jia R, Yang T, et al. Cellulose-based fluorescent
sensor for visual and versatile detection of amines and anions. J Hazard Mater
2020;387:121719. https://doi.org/10.1016/j.jhazmat.2019.121719
.

2
7
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
[26] Cao X, Ding Q, Zhao N, Gao A, Jing Q. Supramolecular self-assembly system based
on naphthalimide boric acid ester derivative for detection of organic amine. Sensors
Actuators, B Chem 2018;256:711–20. https://doi.org/10.1016/j.snb.2017.09.210
.
[27] Liu T, Yang L, Feng W, Liu K, Ran Q, Wang W, et al. Dual-Mode Photonic Sensor
Array for Detecting and Discriminating Hydrazine and Aliphatic Amines. ACS Appl Mater
Interfaces 2020;12:11084–93. https://doi.org/10.1021/acsami.0c00568.
[28] Reinert S, Mohr GJ. Chemosensor for the optical detection of aliphatic amines and
diamines. Chem Commun 2008:2272–4. https://doi.org/10.1039/b717796h
.
[29] Aydıner B. A chemodosimeter approach for selective colorimetric and fluorimetric
cyanide detection using coumarin based fluorescent dyes. J Photochem Photobiol A Chem
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2019;382. https://doi.org/10.1016/j.jphotochem.2019.111916
.
[30] Chemchem M, Yahaya I, Aydıner B, Seferoğlu N, Doluca O, Merabet N, et al. A
novel and synthetically facile coumarin-thiophene-derived Schiff base for selective
fluorescent detection of cyanide anions in aqueous solution: Synthesis, anion interactions,
theoretical study and DNA-binding properties. Tetrahedron 2018;74:6897–906.
https://doi.org/10.1016/j.tet.2018.10.008
.
[31] Çatal E, Keleş E, Seferoǧlu N, Achelle S, Barsella A, Robin Le Guen F, et al.
Triphenylamine-based allylidenemalononitrile chromophores: Synthesis, and photophysical
and second-order nonlinear optical properties. New J Chem 2018;42:15052–60.
https://doi.org/10.1039/c8nj02794c
.
[32] Yanar U, Babür B, Pekyilmaz D, Yahaya I, Aydiner B, Dede Y, et al. A fluorescent
coumarin-thiophene hybrid as a ratiometric chemosensor for anions: Synthesis, photophysics,
anion sensing and orbital interactions.
https://doi.org/10.1016/j.molstruc.2015.11.081
J
Mol Struct 2016;1108:269–77.
.

2
8
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
[33] Shapiro BI. Molecular ensembles of polymethine dyes. ICIS ’06 Int Congr Imaging
Sci - Final Progr Proc 2006;433:65–7. https://doi.org/10.1070/rc2006v075n05abeh001208
.
[34] Bricks JL, Kachkovskii AD, Slominskii YL, Gerasov AO, Popov S V. Molecular
design of near infrared polymethine dyes: A review. Dye Pigment 2015;121:238–55.
https://doi.org/10.1016/j.dyepig.2015.05.016
[35] Mishra A, Behera RK, Behera PK, Mishra BK, Behera GB. Cyanines during the
1990s: a review. Chem Rev 2000;100:1973–2011. https://doi.org/10.1021/cr990402t
.
.
[36] Silva GL, Ediz V, Yaron D, Armitage BA. Experimental and computational
investigation of unsymmetrical cyanine dyes: Understanding torsionally responsive
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
fluorogenic dyes. J Am Chem Soc 2007;129:5710–8. https://doi.org/10.1021/ja070025z.
[37] Hunger K. Industrial dyesꢀ: chemistry, properties, applications. Weinheim: Wiley-
VCH; 2003.
[38] Zollinger H. Color Chemistry. Zürich: WILEY-VHC; 2003.
[39] Matei A, Constantinescu C, Mitu B, Filipescu M, Ion V, Ionita I, et al. Laser printing
of azo-derivative thin films for non-linear optical applications. Appl Surf Sci 2015;336:200–
5. https://doi.org/10.1016/j.apsusc.2014.11.022
.
[40] Zhang L, Cole JM, Waddell PG, Low KS, Liu X. Relating electron donor and
carboxylic acid anchoring substitution effects in azo dyes to dye-sensitized solar cell
performance. ACS Sustain Chem Eng 2013;1:1440–52. https://doi.org/10.1021/sc400183t
.
[41] El-Shishtawy RM, Borbone F, Al-Amshany ZM, Tuzi A, Barsella A, Asiri AM, et al.
Thiazole azo dyes with lateral donor branch: Synthesis, structure and second order NLO
properties. Dye Pigment 2013;96:45–51. https://doi.org/10.1016/j.dyepig.2012.08.002
.
[42] Yahaya I, Seferoğlu N, Seferoğlu Z. Improved one-pot synthetic conditions for
synthesis of functionalized fluorescent coumarin-thiophene hybrids: Syntheses, DFT studies,