A simple chemosensor for ultrasensitive fluorescent “turn-on” detection of Fe3+ and alternant detection of CN-

Article abstract of DOI:10.1080/10610278.2019.1690655

It is worth noting that Fe³⁺ is paramagnetic in nature. Thus, in most of the cases, Fe³⁺ behave as fluorescent quencher which makes it difficult to develop a fluorescent ‘turn-on’ chemosensor. Therefore, it is still a big challenge t

Full text of DOI:10.1080/10610278.2019.1690655

Supramolecular Chemistry
ISSN: 1061-0278 (Print) 1029-0478 (Online) Journal homepage: https://www.tandfonline.com/loi/gsch20
A simple chemosensor for ultrasensitive
3+
fluorescent “turn-on” detection of Fe and
-
alternant detection of CN
Qin-Peng Zhang, Tai-Bao Wei, Jun-Nian An, Yan-Yan Chen, Guan-Fei Gong, Qi
Zhou, Hai-Long Yang, Hong Yao, You-Ming Zhang & Qi Lin
To cite this article: Qin-Peng Zhang, Tai-Bao Wei, Jun-Nian An, Yan-Yan Chen, Guan-Fei Gong,
Qi Zhou, Hai-Long Yang, Hong Yao, You-Ming Zhang & Qi Lin (2019): A simple chemosensor for
3+
-
ultrasensitive fluorescent “turn-on” detection of Fe and alternant detection of CN , Supramolecular
Chemistry, DOI: 10.1080/10610278.2019.1690655
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SUPRAMOLECULAR CHEMISTRY
https://doi.org/10.1080/10610278.2019.1690655
ARTICLE
3+
A simple chemosensor for ultrasensitive fluorescent “turn-on” detection of Fe
-
and alternant detection of CN
a
a
a
a
a
a
a
Qin-Peng Zhang , Tai-Bao Wei , Jun-Nian An , Yan-Yan Chen , Guan-Fei Gong , Qi Zhou , Hai-Long Yang ,
a
a,b
a
Hong Yao , You-Ming Zhang and Qi Lin
a
Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China; Research Center of Gansu Military and Civilian
Integration Advanced Structural Materials; College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, Gansu,
b
P. R. China; College of Chemistry and Chemical Engineering, Lanzhou City University, Lanzhou, Gansu, P. R. China
ABSTRACT
ARTICLE HISTORY
Received 11 September 2019
Accepted 20 October 2019
3
+
3+
It is worth noting that Fe is paramagnetic in nature. Thus, in most of the cases, Fe behave as
fluorescent quencher which makes it difficult to develop a fluorescent ‘turn-on’ chemosensor.
Therefore, it is still a big challenge to devise and synthesise a simple chemosensor that could
selectively detect Fe via fluorescent ‘turn-on’ response. In this paper, A simple fluorescence
chemosensor T based on N,N-(3,3-dimethyl biphenyl)-bis(2-methoxyphenol) has been synthesised.
T could selectively detect Fe via fluorescent ‘turn-on’ response. Meanwhile, the fluorescent spec-
trum limit of T towards Fe was 0.178 nM, the detection limit was much lowest than previously
reported fluorescent chemosensor and has reached to ultrasensitive level. In addition, T could also
KEYWORDS
3
+
Double schiff-base; detection
3
+
−
of Fe and CN ;
3
+
dual-channel chemosensor;
logic gate; test papers
3
+
−
alternately detect CN . Intriguingly, IMPLICATION logic gate was successfully constructed. Finally, the
test papers and films based on T were prepared, which could be used as a fluorescent display
3+
−
material for the detection of Fe and CN .
3
+
In this article, a simple chemosensor (T) for ultrasensitive fluorescent ‘turn-on’ detection of Fe and
−
alternant detection of CN has been designed and synthesised. The fluorescent spectrum detection
3+
limit of T towards Fe was 0.178 nM, the detection limit was much lowest than previously reported
fluorescent chemosensor and has reached to ultrasensitive level. Based on the alternant detection
3+
−
property of T for Fe and CN , the fluorescent ‘ON-OFF-ON’ responding circle, IMPLICATION logic
gate and test kits were constructed and prepared successfully, showing potential for practical
applications in the detection of metal ions, toxic ions as well as smart material aspects.
CONTACT Tai-Bao Wei
weitaibao@126.com; Qi Lin
linqi2004@126.com
Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of
Education of China; Research Center of Gansu Military and Civilian Integration Advanced Structural Materials; College of Chemistry and Chemical Engineering,
Northwest Normal University, Lanzhou, Gansu 730070, P. R. China
Supplemental data for this article can be accessed here.
©
2019 Informa UK Limited, trading as Taylor & Francis Group

2
Q.-P. ZHANG ET AL.
Introduction
Experimental sections
In the recent decade, the ultrasensitive detection of
anions, cations and biomolecules has become increas-
ingly important in the fields of food detection (1–3), clin-
ical diagnostics (4–9), environmental monitoring (10–16),
therefore, many scientists all over the world have been
working in the area and developed numerous methods to
achieve ultrasensitive detection of multi-analyte. For
instance, Wu and co-workers designed and synthesised
a conductive nanowire-mesh biosensor for ultrasensitive
detection of serum reactive protein in Melanoma (17).
Chattopadhyay and co-workers reported a lysosome-
targetable fluorescent sensor for ultrasensitive detection
Materials and instruments
All chemical reagents were commercially available at ana-
lytical grade and used without further purification. All sol-
vents were purified and dried by standard methods. The
cations were used from their perchlorate salts and pur-
chased from Alfa Aesar Chemical Reagent. Meanwhile, the
anions were used from their tetrabutylammonium (TBA)
salts, which were purchased from Sigma Aldrich Chemical.
Fresh double distilled water was used throughout
1
the experiment. The H NMR spectra were recorded
on a Mercury-600 BB spectrometer at 600 MHz and
a Mercury-400 BB spectrometer at 400 MHz, respectively.
2
+
of Hg in living cells and real samples (18). Although
chemists have been much successful at developing detec-
tion methods for multi-analyte, designing and developing
a chemosensor that can recognise multi-analyte conveni-
ently and efficiently is still a hot topic to be solved.
The detection of cations and anions has attracted more
and more attention, due to they perform important roles in
a wide range of biological and ecological systems. For
13
C NMR spectra were recorded on a Mercury-600 BB spec-
trometer at 151 MHz and a Mercury-400 BB spectrometer at
01 MHz. The fluorescence spectra were recorded with
a Shimadzu RF-5301 spectrofluorimeter. Ultraviolet–visible
UV–vis) spectra were recorded on a Shimadzu UV-2550
1
(
spectrometer. Mass spectra were recorded on a Bruker
Esquire 6000 MS instrument. Melting points were tested
on an X-4 digital melting-point apparatus. The infrared
spectra were performed on Digilab FTS-3000 Fourier trans-
form-infrared spectrophotometer. The morphologies and
3+
example, Fe , as one of the most important elements in
metabolic processes, plays indispensable and versatile
roles in a lot of biochemical processes at the cellular level
for both human being and all the other biological worlds
3+
3+
−
sizes of compound T, T-Fe and T-Fe -CN were investi-
gated using field emission scanning electron microscopy
3+
(
19–23). In addition, the deficiency and excess of Fe ions
(FE-SEM, JSM-6701F).
could cause many health problems in living organisms,
such as heart disease, cancers, diabetes, anaemia and
other dysfunction of organs (24–26). Moreover, anions are
linked with various biological, environmental, pathological
processes. Especially, cyanide ion is considered as a useful
anion in many fields, including the fibre and resin manu-
facturing, metallurgy, and herbicide production. Although
cyanide has important application value in chemistry and
chemical industry fields, cyanide is also well known as
a hazardous chemical in biological systems and the envir-
onment (27, 28). Therefore, it is of great theoretical and
practical significance to explore high-efficiency and simple
General procedure for UV-vis experiments
All the UV-vis experiments were carried out in DMSO/H2
O (8: 2, v/v) binary solution on a Shimadzu UV-2550 spectro-
meter. Any changes in the UV-vis spectra of the synthesised
compound were recorded on addition of cations and
anions while keeping the ligand concentration constant
−
4
3+
(
2.0 × 10 M) in all experiments. Different cations (Fe ,
2+
+
2+
2+
2+
2+
2+
2+
2+
3+
Cu , Ag , Ca , Co , Ni , Pb , Zn , Cd , Mg , La ,
3+
3+
−
−
−
−
−
−
Eu and Tb ) and anions (CN , F , Cl , Br , I , AcO , H
PO , HSO , ClO , S , N and SCN ) were used for the
2
−
4
−
−
4
2-
−
3
−
3+
chemosensor for the quantitative detection of Fe and
4
−
UV-vis experiments.
CN in biological and environmental system.
In light of the above results and as part of our
research interest in ion recognition field (29–32), we
reported a simple and efficient chemosensor T, which
General procedure for fluorescence spectra
experiments
3+
could achieve the ultrasensitive detection of Fe by
fluorescent ‘turn-on’ response. In addition, T could not
All the fluorescent spectroscopy was carried out in
3
+
−
only detect Fe but also detect CN successively. Based
on the successive recognition property of T, the fluores-
cent ‘ON-OFF-ON’ responding circle and IMPLICATION
logic gate were constructed by sequential addition of
DMSO/H O (8: 2, v/v) binary solution on a Shimadzu
2
RF-5301 spectrometer. Any changes in the fluorescence
spectra of the synthesised compound were recorded on
addition of cations and anions while keeping the ligand
3
+
−
−4
Fe and CN into T solution. Moreover, the test kits and
films loading T were prepared, which could be used as
a fluorescent display material.
concentration constant (2.0 × 10 M) in all experiments.
3
+
2+
+
2+
2+
2+
2+
Different cations (Fe , Cu , Ag , Ca , Co , Ni , Pb ,
2+
2+
2+
3+
3+
3+
−
Zn , Cd , Mg , La , Eu and Tb ) and anions (CN ,

SUPRAMOLECULAR CHEMISTRY
3
−
−
−
−
−
−
−
−
2-
−
F , Cl , Br , I , AcO , H PO , HSO , ClO , S , N and
the DMSO is a good solvent for T while water is a poor
solvent for T, as shown in Figure S4, upon the addition of
water into the DMSO solution of T with the increase of the
water volume fractions, the fluorescent emission intensity
at 528 nm reached the strongest state when the water
volume fraction was at 20%. However, when the water
contents exceeded 20%, the fluorescence intensity of
T was decreased, which could be attributed to the forma-
tion of precipitate when more water was added into the
T (water fractions 20%) solution. Based on above these
2
4
4
4
3
−
SCN ) were used for the fluorescent experiments.
Synthesis and characterisation of chemosensor T
The chemosensor T was synthesised by 4-hydroxy-
3
-methoxybenzaldehyde (0.684 g, 4.5 mmol), 3,3′-
dimethylbenzidine (0.425 g, 2.0 mmol) and acetic acid
2 mL) were dissolved in absolute ethanol (60 mL), the
(
reaction mixture was stirred under reflux for 12 h at 85°C.
At the end of reaction, the rufous solution was obtained
and extracted with dichloromethane, then dichloro-
methane layer was dried under vacuum to obtain
a yellow powder, the yellow powder was recrystallised
with ethanol to give a yellow powder product T (0.8068
results, we chose the solvent composition of DMSO/H2
O (8:2. v/v) to investigate fluorescent property of T in
throughout the experiment. Subsequently, the
recognition properties of the chemosensor T towards
3
+
2+
+
2+
2+
various metal ions (including Fe , Cu , Ag , Ca , Co ,
2+
2+
2+
2+
2+
3+
3+
3+
Ni , Pb , Zn , Cd , Mg , La , Eu and Tb ) were
g) in 84% yield. The melting point of compound T is over
1
investigated by UV-vis and fluorescent spectra in
3
00°C. H NMR (CDCl , 600 MHz, room temperature) δ
3
DMSO/H O (8: 2, v/v) binary solution.
(
ppm): 8.30 (s, 2 H), 7.65 (d, J = 1.8 Hz, 2 H), 7.48 (d, J = 2.1
Hz, 4 H), 7.30 (dd, J = 8.1, 1.8 Hz, 2 H), 6.99 (dd, J = 9.3, 8.0
Hz, 4 H), 5.96 (s, 2 H), 4.0 (s, 6 H), 2.43 (s, 6 H),. C NMR
CDCl , 151 MHz) δ/ppm: 158.79, 150.28, 148.82, 147.03,
2
3
+
First, in the UV-vis spectra, with 5.0 equiv Fe was
−
4
13
added into T solution (2.0 × 10 M), the absorption
peaks at 285 nm and 305 nm increased obviously
(
3
(Figure 2), while the one at 363 nm decreased signifi-
1
1
37.91, 132.09, 129.50, 128.69, 125.07, 124.81, 118.19,
14.16, 108.60, 56.07, 18.06. ESI-MS m/z: calcd for C
cantly, and accompanied by the solution colour change
from pale yellow to colourless. The absorption peaks
change may be ascribed to the newly formed complex
30
+
H N O [T+ H] : 481.2122; found: 481.21216.
2
8 2 4
3+
between T and Fe . In comparison, other cations no
obvious changes were observed in colour (inset of
Figure 2). Furthermore, to confirm the selectivity of
Calculation formula of LOD
Linear Equation: Y ¼ aX þ b
3+
T towards Fe , the competitive experiment was imple-
sffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
2
mented by adding 5.0 equiv various metal ions (includ-
ÆðFi ꢀ F0Þ
2
+
+
2+
2+
2+
2+
2+
2+
2+
δ ¼
ðN ¼ 20Þ
ing Cu , Ag , Ca , Co , Ni , Pb , Zn , Cd , Mg ,
N ꢀ 1
3+
3+
3+
La , Eu and Tb ) into the mixed solution of T and
Fe respectively. The results showed that these compe-
6
3+
LOD = K × δ/S (K = 3, S = a × 10 )
F0 is fluorescence intensity of T, Fi is the average of
fluorescent intensity F0.
titive metal ions exerted no influence on the detection of
Fe (Figure 3).
3+
Second, in the fluorescent spectra, when 5.0 equiv
3
+
2+
+
2+
2+
2+
2+
2+
various (Fe , Cu , Ag , Ca , Co , Ni , Pb , Zn ,
Results and discussion
2+
2+
3+
3+
3+
Cd , Mg , La , Eu and Tb ) metal ions were added
into T, T and T+ other cations showed very weak fluor-
escence (Figure 4). However, upon the addition of 5.0
equiv Fe into T solution, T emitted brilliant yellow fluor-
escence at 528 nm, which could be distinguished by
naked-eyes under the irradiation of a portable UV-lamp
As shown in Figure 1, the chemosensor T was synthesised
1
13
and characterised by H NMR, C NMR and ESI-MS (Figure
S1-S3). Next, to ascertain the optimum water content sys-
tem of T solution, the fluorescent experiment of different
volume fractions of water content was carried out. Because
3+
Figure 1. (colour online) Synthesis of chemosensor T.

4
Q.-P. ZHANG ET AL.
3
+
(
Figure 6). Upon sequential addition of Fe (0–0.18
−
4
equiv.) into T solution (2.0 × 10 M), the absorption
peaks at 285 nm and 305 nm increased gradually,
while the one at 363 nm decreased, which could be
attributed to the formation of coordination bonds
between Fe and oxygen atoms of T. As a result, this
led to obvious colour change from pale yellow to colour-
less, which could be observed by the naked eyes (inset of
Figure 2). The detection limit of UV-vis spectra changes
for Fe was calculated to be 1.58 nM on the basis of the
δ/S method (Figure S5). In the fluorescent titration
experiment (Figure 7), the emission intensity of T at
28 nm was enhanced progressively with the increasing
3
+
3+
3
5
3+
concentration of Fe (0–0.18 equiv.), which could be
caused by the inhibition of PET process due to the for-
Figure 2. (colour online) UV-vis absorption spectra of chemo-
3
+
−
4
mation of coordination bonds between Fe and oxygen
sensor T (2 × 10 M) in DMSO/H O (8: 2, v/v) binary solution in
2
3
+
3+
atoms of T (forming the complex T-Fe ). Moreover, the
the presence of Fe and other cations (5.0 equiv.). Inset: Colour
changes observed at natural light after 5.0 equiv. various cations
were added into T.
3
+
detection limit of fluorescent spectra changes for Fe
was 0.178 nM (Figure S6). It is worth noting that the
3+
fluorescent detection limit of T for Fe was lowest
than previously reported fluorescent chemosensor
(Table 1) (33–41), corroborating that chemosensor
(
365 nm). In addition, to validate the selectivity of T for
3
+
3+
Fe , the control experiment was carried out by adding
other competitive metal ions into the mixed solution
of T and Fe respectively. As a result, other competitive
T could achieve ultrasensitive detection of Fe in
DMSO/H O (8: 2, v/v) binary solution.
2
3
+
3+
Then, the successive recognition property of T-Fe
−
−
−
−
−
−
−
cations could not induce any obvious changes for
towards various anions (CN , F , Cl , Br , I , AcO , H PO ,
2 4
3+
−
−
2-
−
−
the detecting process of Fe (Figure 5). Therefore,
HSO , ClO , S , N and SCN ) was further investigated
4 4 3
3+
T showed specific fluorescent selectivity towards Fe in
by UV-vis experiment in DMSO/H O (8: 2, v/v) binary solu-
2
DMSO/H O (8: 2, v/v) binary solution.
tion. In the UV-vis experiments (Figure S7), when 5.0 equiv
2
−
3+
−5
To further explore the detection property of chemo-
CN was added into T-Fe solution (2.0 × 10 M), the
3+
3+
−
sensor T towards Fe in DMSO/H O (8: 2, v/v) binary
absorption peaks of T-Fe -CN at 285 nm and 305 nm
declined obviously, while the one at 363 nm increased
sharply. Subsequently, the control experiments were
2
solution, UV-vis and fluorescent titration experiments
were carried out. In the UV-vis titration experiments
3
+
Figure 3. (colour online) UV-vis absorption histogram of chemosensor T with addition of 5.0 equiv. Fe in the presence of various
cations in DMSO/H O (8: 2, v/v) binary solution (λ = 285 nm).
2
em

SUPRAMOLECULAR CHEMISTRY
5
−
(
inset of Figure 8) after 5.0 equiv CN was added into
3
+
T-Fe solution, and other anions could not induce same
fluorescent changes. In order to verify the selectivity of
T-Fe towards CN , the control experiments were car-
3
+
−
3
+
ried out by adding various anions into T-Fe solution,
respectively. The results showed these anions could not
−
induce any interference for the CN sensing process
(
Figure 9). Meanwhile, to further explore the detection
3
+
−
property of T-Fe for CN , fluorescent titration experi-
ment was also carried out. As shown in Figure S10, with
−
the increasing concentration of CN (0–9.80 equiv.), the
fluorescent emission intensity at 528 nm decrease gra-
dually, which indicated PET interaction was recovered.
Meanwhile, the fluorescent spectrum detection limit of
3
+
−
T-Fe towards CN was obtained to be 206 nM on the
basis of 3δ/S method.
Figure 4. (colour online) Fluorescent emission spectra of che-
−
4
mosensor T (2 × 10 M) in DMSO/H O (8: 2, v/v) binary solution
2
3+
in the presence of Fe and other cations (5.0 equiv.) (λex = 390
nm). Inset: Colour changes observed at UV lamp (365 nm) after
5.0 equiv. various cations were added into T.
3+
−
performed to investigate the selectivity of T-Fe for CN
under the competition conditions. As shown in Figure S8,
other competitive anions could not cause any obvious
−
change for the detection process of CN . In addition, UV-
vis titration experiment was implemented to probe the
3
+
−
detection property of T-Fe for CN . As shown in Figure
3+
S9, the UV-vis spectrum detection limit of T-Fe towards
CN was calculated to be 35.20 nM in UV-vis spectra.
−
Moreover, the fluorescent experiment was also uti-
lised to investigated successive recognition property of
3
+
−
−
−
−
−
T-Fe towards different anions (CN , F , Cl , Br , I ,
−
−
−
−
2-
−
−
AcO , H PO , HSO , ClO , S , N and SCN ) in
2
4
4
4
3
DMSO/H O (8: 2, v/v) binary solution. As shown in
Figure 8, the fluorescence of T-Fe was quenched
2
Figure 6. (colour online) UV-vis titration spectra of chemosensor
T with increasing concentrations of Fe .
3
+
3
+
3
+
Figure 5. (colour online) Fluorescent histogram of chemosensor T with addition of 5.0 equiv. of Fe in the presence of various cations
in DMSO/H O (8: 2, v/v) binary solution (λex = 390 nm, λem = 528 nm).
2

6
Q.-P. ZHANG ET AL.
3
+
Figure 8. (colour online) Fluorescent emission spectra of T-Fe
Figure 7. (colour online) Fluorescent titration spectra of chemo-
−
4
3+
(2 × 10 M) in DMSO/H O (8: 2, v/v) binary solution in the
presence of CN and other anions (5.0 equiv.) (λ = 390 nm).
sensor T with increasing concentrations of Fe .
2
−
ex
Inset: Colour changes observed at UV lamp (365 nm) after 5.0
Table 1. Comparison of detection limit of different fluorescent
chemosensors for Fe .
equiv. various anions were added into T.
3+
Detection
Limit (nM)
Fluorescent Chemosensors
Ref
3
+
between chemosensor T and Fe . As shown in Figure
S12, the inflexion point appeared at the mole fraction of
0
N/P codoped carbon dots
Nitrogen and phosphorus codoped
carbon nanodots
B, N, S-co-doped carbon dots
Graphene quantum dots
Octavinyl-polyhedral oligomeric
silsesquioxane
330.0
1.8
(33)
(34)
.34, which demonstrated the binding mode of 2:1
90.0
450.0
0.9
(35)
(36)
(37)
3
+
between chemosensor T and Fe . Moreover, the ESI-
MS experiment was performed, as shown in the Figure
S13, complex T- Fe showed the peaks at m/z = 259.98
corresponding to [2T + Fe + Na ] after the appro-
priate amount of Fe was added into T solution for
forming complex T-Fe , the result proved the 2:1 com-
plexation stoichiometry between molecule T and Fe ,
3
+
3-aminopyridazine-functonalized
25.4
(38)
3+
+ 4+
rhodamine B
Indolizino[3,2-c]quinoline derivative
Rhodamine B-based
1000.0
12.8;11.0
(39)
(40)
3+
3
+
2
2
-methoxybenzylamine and
-thiophenemethylamine
3+
2,2′ thiobis (ethylamine)-
300.0
(41)
functonalized 2-hydroxy
which further indicated the existence of coordination
interactions between molecule T and Fe .
1-naphthaldehyde
3+
Chemosensor T
0. 178
This work
Based on the above these results, we proposed the
possible recognition mechanism of chemosensor
3
+
−
T towards Fe and CN . As shown in Scheme 1, in the
3
+
Furthermore, the detection mechanism of chemosen-
absence of Fe , the oxygen atom of methoxy of T could
partially transfer an electron to the biphenyl (PET ON) (42,
43) and a hydroxyl proton could be transferred to
a neighbouring methoxy oxygen along with the forma-
tion of a intramolecular hydrogen bonds (OH . . . .O), which
led to a relative weak fluorescent emission at 528 nm.
3
+
−
sor T for Fe and CN were investigated by FT-IR, Job’
plot, SEM and the density functional theoretical (DFT). In
the IR spectra of T and its complex (Figure S11), the
stretching vibration absorption peaks of -OH and H
3
−
1
C-O- on chemosensor T appeared at 3408 cm and
−
1
3+
1
274 cm , respectively. Whereas the absorption peaks
Upon the addition of Fe into T solution (forming the
3
+
3+
of -OH disappeared after the addition of 0.24 equiv. Fe
complex T-Fe ), the oxygen atoms of hydroxyl and
3
+
into T (forming the complex T-Fe ), and absorption
methoxy group participated in the coordination with
3+
peaks of H C-O- was weaken. The results indicated that
Fe , which destroyed intramolecular hydrogen bonds
between hydroxyl and methoxy group, so that inhibited
the PET process (PET OFF). Therefore, a remarkable fluor-
3
3+
3+
T coordinated with Fe via O-Fe -O coordination
bonds. Subsequently, upon the addition of 5.0 equiv
−
3+
3+
CN into the complex T-Fe , the absorption peaks of -
escence enhancement of T was induced by Fe at 528
−
1
−
3+
OH recovered to 3402 cm , suggesting the existence of
competitive coordination interaction between CN
and T-Fe . In addition, Job’s plot analysis was imple-
nm. After the addition of CN into T-Fe , the coordina-
−
3+
tion bonds of the complex T-Fe were destroyed due to
CN competitively bound to Fe . Therefore, PET process
3
+
−
3+
mented to evaluate the complexation behaviour
(PET ON) and fluorescence of T were recovered.

SUPRAMOLECULAR CHEMISTRY
7
3
+
−
Figure 9. (colour online) Fluorescent histogram of T-Fe with addition of 5.0 equiv. CN in the presence of various anions in DMSO/H
O (8: 2, v/v) binary solution (λex = 390 nm, λem = 528 nm).
2
3
+
Scheme 1. (colour online) The proposed detection mechanism of chemosensor T to Fe and CN.
Subsequently, the SEM was also utilised for further
investigating the morphological features of the powder
T and its complex. As shown in Figure S14, the micro-
structure of T was blocky structure. However, the struc-
ture of T transformed into laminar microstructure after
(DFT) calculations based on the theoretical level of B3LYP/
6-31G (44), and the optimised structures of the ground
state were shown in Figure S15. The orbital energies of
3+
the HOMO and LUMO of T and T-Fe were also obtained
(Table S1). As shown in Figure 10, the energy gap between
3
+
3+
adding Fe into the T, which could be attribute to the
the HOMO and LUMO in T and T-Fe was calculated to be
3
+
complexation interaction between T and Fe . In addi-
3.68 eV and 3.21 eV, respectively. Decrease in the HOMO-
3
+
−
tion, when T-Fe was treated with CN , the laminar
microstructure was transformed into a plicated micro-
structure, which could be caused by the competitive
LUMO energy gaps of T could stabilise the whole system
3+
3+
after T coordinate with Fe (forming the complex T-Fe )
(45), indicating the proposed coordination mechanism of
−
3+
3+
coordination interaction between CN and T-Fe .
T with Fe was rational.
In order to further study the possible coordination
The reversibility is a significant aspect for a chemosensor
to be widely applied in the ionic and molecular detection
field. Hence, the reversibility of chemosensor T was further
3+
interaction between T and Fe , the complex geometry of
3+
T-Fe was optimised by density functional theoretical

8
Q.-P. ZHANG ET AL.
3
+
Figure 10. (colour online) HOMO and LUMO orbitals of T, T-Fe .
3
+
−
investigated by alternating the addition of Fe and CN
(fluorescent quenching), which showed ‘Reading-Erasing-
Writing-Reading’ cyclic behaviour with the help of reversi-
ble IMPLICATION logic operations Figure 11(a–d). In the
into the T solution. Initially, T was induced to generate
strong fluorescent emission after the addition of Fe into
T solution (forming the complex T-Fe ), which Fe acts as
an ‘ON switch’ in the detection process. Subsequently, with
the addition of CN into the complex T-Fe (forming the
complex T-Fe -CN ), T-Fe -CN showed obvious fluor-
escence quenching by showing ‘OFF’ behaviour. The ‘ON-
OFF-ON’ switching process could be repeated at least four
times with little fluorescent efficiency loss (Figure S16).
Therefore, these results not only verified T possessed excel-
lent reversibility but also T could be used as excellent ‘ON-
OFF-ON’ fluorescent switch (Figure S17).
Based on above the reversible property of
T, T can switch between different fluorescent emission
states, i.e. ‘ON’ (fluorescent enhancement) or ‘OFF’
3+
3+
3+
3+
−
IMPLICATION logic gate, Fe (Input 1) and CN (Input 2)
3+
−
are defined as two inputs, the presence of Fe or CN could
−
3+
3+
−
be defined as 1, the absence of Fe or CN be defined as 0.
Meanwhile, the fluorescent intensity of T at 528 nm was
defined as the output signal, and fluorescent enhancement
and fluorescent quenching of T were defined as ‘state 1’
and ‘state 0’, respectively. From the truth table in Fig. 14a-b,
3+
−
3+
−
3+
it could be observed that the presence of only Fe (Input
1 = 1 and Input 2 = 0) induce a strong fluorescent emission
implying that the output signal was above the threshold
value (output = 0). However, other possible input combina-
tions [(0, 0), (0, 1), and (1, 1)] could lead to the output signal
below the threshold value, i.e. the output = 1. Therefore, an
Figure 11. (colour online) (a) Truth table for the IMPLICATION logic gate; (b) IMPLICATION logic gate represented using a conventional
gate notation; (c) Histogram of the output signals in presence of different inputs; (d) Feedback loop showing the reversible logic
operations for the memory element with ‘Reading-Erasing-Reading-Writing’ functions.

SUPRAMOLECULAR CHEMISTRY
9
IMPLICATION logic gate was successfully constructed by
the bright yellow writing trace could be erased by brush-
ing CN on the film again. Therefore, the thin films based
on chemosensor T could act as convenient and reprodu-
cible fluorescent security display materials.
−
monitoring the fluorescent change of chemosensor T at
3+
−
5
28 nm with the two inputs (Fe and CN ).
In order to further exploit the practical application of
chemosensor T, the test papers and thin films were
prepared. First, test papers were obtained by immersing
−
2
the filter papers into T (1 × 10 M) DMSO/H O (8: 2, v/v)
2
Conclusion
binary solution and drying in air. Intriguingly, the test
papers could serve as an efficient test kits for convenient
detection of Fe in water. As shown in Figure 12(b),
To sum up, we have successfully developed a colourimetric
and fluorescent dual-channel chemosensor T based on
double schiff-base. Interestingly, T could selectively detect
3+
these test papers exhibit weak fluorescence emission,
3
+
3+
upon the addition of different concentrations Fe
water solution (from 1.0 M to 1 × 10
Fe via fluorescent ‘turn-on’ response and the fluorescent
−
10
3+
M) into the test
spectrum detection limit of T towards Fe was 0.178 nM.
3+
papers, the test papers exhibited distinct fluorescence
Simultaneously, upon the addition of Fe into T solution,
T showed an obvious colour change from pale yellow to
3
+
response for Fe . The lowest response concentration of
3+
−9
−
these test papers to Fe was 10 M.
colourless. In addition, T could also alternately detect CN .
In addition, the thin films were also prepared by load-
Next, the fluorescent ‘ON-OFF-ON’ responding circle also
−2
ing T (DMSO/H O, 1 × 10 M) binary solution on the silica
was constructed, which could be repeated over 4 times by
2
3+
−
plate and dried in air. As shown in Figure 12(a), the thin
films exhibited weak fluorescence under the irradiation of
UV lamp (365 nm). However, when writing on the films
the successive addition of Fe and CN into T. The fluor-
escent ‘ON-OFF-ON’ responding circle was utilised as an
IMPLICATION logic gate at the molecular level. Finally, the
test papers and films loading T were prepared, which could
be used as a fluorescent display material for the detection
3+
with a capillary tube dipping in Fe water solution,
a bright yellow fluorescent writing trace appeared and
3
+
3+
−
Figure 12. (colour online) (a) Photos of the silica gel plates loaded with T or T-Fe were used to detect Fe and CN in aqueous
solutions under UV lamp at 365 nm; (b) Fluorescent colour changes (under the UV lamp, at 365 nm) of T based on test kit after
3+
−10
addition of various concentration Fe aqueous solutions (from 0 M to 1 × 10 M).

1
0
Q.-P. ZHANG ET AL.
3+
−
of Fe and CN . This work will be of great value in ion
recognition, environmental minoring and smart materials.
(17) Lin, Z.T.; Li, Y.X.; Gu, J.H.; Wang, H.E.; Zhu, Z.; Hong, X.;
Zhang, Z.J.; Lu, Q.Q.; Qiu, J.Y.; Wang, X.F.; Bao, J.M.; Wu, T.
F. Adv. Funct. Mater. 2018, 28, 1802482–1802492. DOI:
1
0.1002/adfm.201802482.
(
18) Sarkar, A.; Chakraborty, S.; Lohar, S.; Ahmmed, E.; Saha, N.C.;
Mandal, S.K.; Dhara, K.; Chattopadhyay, P. Chem. Res.
Toxicol. 2019, 32, 1144–1150. DOI: 10.1021/acs.
chemrestox.9b00005.
Disclosure statement
No potential conflict of interest was reported by the authors.
(19) Zhu, H.; Peck, S.C.; Bonnot, F.; van der Donk, W.A.;
Klinman, J.P. J. Am. Chem. Soc. 2015, 137,
Funding
1
0448–10451. DOI: 10.1021/jacs.5b03907.
(
20) Basoglu, A.; Tosun, G.; Ocak, M.; Alp, H.; Yayli, N.; Ocak, U.
J. Agric. Food Chem. 2015, 63, 2654–2659. DOI: 10.1021/
jf505336d.
This work was supported by The National Natural Science
Foundation of China (NSFC) (No. 21574104; 21662031;
2
1661028).
(
(
(
(
21) Ebrahimi, K.H.; Hagedoorn, P.L.; Hagen, W.R. Chem. Rev.
2
015, 115, 295–326. DOI: 10.1021/cr5004908.
22) Rouault, T.A.;. Nat. Chem. Biol. 2006, 2, 406–414. DOI:
0.1038/nchembio807.
23) D’Autreaux, B.; Tucker, N.P.; Dixon, R.; Spiro, S. Nature.
005, 437, 769–772. DOI: 10.1038/nature03953.
References
1
(
(
(
(
1) Deng, D.D.; Yang, H.; Liu, C.; Zhao, K.; Li, J.G.; Deng, A.P.
Food Chem. 2019, 277, 595–603. DOI: 10.1016/j.
foodchem.2018.10.129.
2) Zhang, G.X.; Ji, R.X.; Kong, X.Y.; Ning, F.J.; Liu, A.K.; Cui, J.
C.; Ge, Y.Q. RSC Adv. 2019, 9, 1147–1150. DOI: 10.1039/
C8RA08967A.
3) Zhou, J.W.; Zou, X.M.; Song, S.H.; Chen, G.H. J. Agric. Food
Chem. 2018, 66, 1307–1319. DOI: 10.1021/acs.
jafc.7b05119.
4) Prince, A.C.; Aditi Jani, A.; Korb, M.; Tipirneni, K.E.;
Kasten, B.B.; Rosenthal, E.L.; Warram, J.M. J. Surg. Oncol.
2
24) Haehling, S.V.; Jankowska, E.A.; van Veldhuisen, D.J.;
Ponikowski, P.; Anker, S.D. Nat. Rev. Cardiol. 2015, 12,
6
59–669. DOI: 10.1038/nrcardio.2015.109.
(
(
(
(
(
25) Lopez, A.; Cacoub, P.; Macdougall, I.C.; Peyrin-Biroulet, L.
Seminar. 2016, 387, 907–916.
26) Wu, J.S.; Liu, W.M.; Ge, J.C.; Zhang, H.Y.; Wang, P.F. Chem.
Soc. Rev. 2011, 40, 3483–3495. DOI: 10.1039/c0cs00224k.
27) Jung, K.H.; Lee, K.H. Anal. Chem. 2015, 87, 9308–9314.
DOI: 10.1021/acs.analchem.5b01982.
28) Kim, H.J.; Ko, K.C.; Lee, J.H.; Lee, J.Y.; Kim, J.S. Chem.
Commun. 2011, 47, 2886–2888. DOI: 10.1039/c0cc05018k.
29) Lin, Q.; Jiang, X.M.; Ma, X.Q.; Liu, J.; Yao, H.; Zhang, Y.M.;
Wei, T.B. Sens. Actuators B. 2018, 272, 139–145. DOI:
2
017, 116, 898–906. DOI: 10.1002/jso.24733.
5) Bruno, J.G.; Sivils, J.C.; Phillips, T. J. AOAC. Int. 2017, 100,
95–899. DOI: 10.5740/jaoacint.17-0163.
6) Chauhan, B.; Jalalpure, S. Pharm. Methods. 2016, 7,
9–103. DOI: 10.5530/phm.2016.7.15.
(
(
(
8
1
0.1016/j.snb.2018.05.094.
9
(
(
(
30) Lin, Q.; Fan, Y.Q.; Gong, G.F.; Mao, P.P.; Wang, J.; Guan, X.
W.; Liu, J.; Zhang, Y.M.; Yao, H.; Wei, T.B. Sustainable.
Chem. Eng. 2018, 6, 8775–8781. DOI: 10.1021/
acssuschemeng.8b01124.
31) Zhang, Y.M.; Zhu, W.; Huang, X.J.; Qu, W.J.; He, J.X.;
Fang, H.; Yao, H.; Wei, T.B.; Lin, Q. Sustainable. Chem. Eng.
7) Mauk, M.; Song, J.Z.; Bau, H.H.; Gross, R.; Bushman, F.D.;
Collman, R.G.; Liu, C.C. Lab. Chip. 2017, 17, 382–394. DOI:
1
0.1039/C6LC01239F.
8) Kim, J.; Campbell, A.S.; Wang, J. Talanta. 2018, 177,
63–170. DOI: 10.1016/j.talanta.2017.08.077.
9) Scirica, B.M.;. Clin. Chem. 2017, 63, 186–195. DOI:
0.1373/clinchem.2016.255539.
(
(
1
2018, 6, 16597–16606. DOI: 10.1021/acssuschemeng.
1
8
b03824.
(
10) Zhao, F.; Zhou, X.Y.; Liu, Y.; Shi, Y.; Dai, Y.F.; Yu, G.H. Adv.
Mater. 2019, 31, 1806446–1806452. DOI: 10.1002/
adma.201806446.
32) Shi, B.B.; Liu, Y.Z.; Zhu, H.T.Z.; Vanderlinden, R.T.;
Shangguan, L.Q.; Ni, R.D.; Acharyya, K.; Tang, J.H.;
Zhou, Z.X.; Li, X.P.; Huang, F.H.; Sang, P.J. J. Am.
Chem. Soc. 2019, 141, 6494–6498. DOI: 10.1021/
jacs.9b02281.
(11) Li, X.; Li, Z.; Yang, Y.W. Adv. Mater. 2018, 30, 1800177–-
1800183. DOI: 10.1002/adma.201800177.
(
12) Mirica, K.A.; Azzarelli, J.M.; Weis, J.G.; Schnorr, J.M.;
Swager, T.M. Proc. Natl. Acad. Sci. U. S. A. 2013, 110,
E3265–E3270. DOI: 10.1073/pnas.1307251110.
(
(
(
(
33) Shangguan, J.F.; Huang, J.; He, D.G.; He, X.X.; Wang, K.M.;
Ye, R.Z.; Yang, X.; Qing, T.P.; Tang, J.L. Anal. Chem. 2017,
8
9, 7477–7484. DOI: 10.1021/acs.analchem.7b01053.
(
(
(
13) Jayawardane, B.M.; McKelvie, I.D.; Kolev, S.D. Anal. Chem.
34) Shi, B.F.; Su, Y.B.; Zhang, L.L.; Huang, M.J.; Liu, R.J.;
2015, 87, 4621–4626. DOI: 10.1021/acs.analchem.5b00125.
Zhao, S.L. ACS Appl. Mater. Interfaces. 2016, 8,
14) Lim, S.H.; Feng, L.; Kemling, J.W.; Musto, C.J.; Suslick, K.S.
Nat. Chem. 2009, 1, 562–567. DOI: 10.1038/nchem.360.
15) Prasad, R.M.; Lauterbach, S.; Kleebe, H.-J.; Merdrignac-
Conanec, O.; Barsan, N.; Weimar, U.; Gurlo, A. ACS Sens.
1
0717–10725. DOI: 10.1021/acsami.6b01325.
35) Liu, Y.H.; Duan, W.X.; Song, W.; Liu, J.J.; Ren, C.L.; Wu, J.;
Liu, D.; Chen, H.L. ACS Appl. Mater. Interfaces. 2017, 9,
1
2663–12672.
2
017, 2, 713–717. DOI: 10.1021/acssensors.7b00064.
16) Su, S.; Wu, W.H.; Gao, J.M.; Lu, J.X.; Fan, C.H. J. Mater. Chem.
012, 22, 18101–18110. DOI: 10.1039/c2jm33284a.
36) Zhu, X.W.; Zhang, Z.; Xue, Z.J.; Huang, C.H.; Shan, Y.;
(
Liu, C.; Qin, X.Y.; Yang, W.S.; Chen, X.; Wang, T. Anal.
2

SUPRAMOLECULAR CHEMISTRY
11
Chem. 2017, 89, 12054–12058. DOI: 10.1021/acs.
analchem.7b02499.
37) Omer, N.; Zhang, F.Y.; Zhao, G.; Guang, S.Y.; Xu, H.Y. Analyst.
(41) Lee, S.Y.; Yang, M.; Kim, C. Spectrochim. Acta Part
A. 2018, 205, 622–629. DOI: 10.1016/j.saa.2018.
07.091.
(
(
(
2
019, 144, 3414–3421. DOI: 10.1039/C9AN00070D.
38) Cheng, Z.; Zheng, L.; Xu, H.; Pang, L.; He, H. Anal. Methods.
019, 11, 2565–2570. DOI: 10.1039/C9AY00499H.
(42) Asthana, S.K.; Kumar, A.; Neeraj,; Shweta,; Hira, S.K.;
Manna, P.P.; Upadhyay, K.K. Inorg. Chem. 2017, 56,
3315–3323. DOI: 10.1021/acs.inorgchem.6b02752.
(43) Gupta, A.S.; Paul, K.; Luxami, V. Anal. Methods. 2018, 10,
983–990. DOI: 10.1039/C7AY02779F.
(44) Bao, X.F.; Shi, J.X.; Nie, X.M.; Zhou, B.J.; Wang, X.L.;
Zhang, L.Y.; Liao, H.; Pang, T. Bioorg. Med. Chem. 2014,
22, 4826–4835. DOI: 10.1016/j.bmc.2014.06.054.
(45) Wang, Y.; Chang, H.Q.; Wu, W.N.; Zhao, X.L.; Yang, Y.;
Xu, Z.Q.; Xu, Z.H.; Jia, L. Sens. Actuators B. 2017, 239,
60–68. DOI: 10.1016/j.snb.2016.07.170.
2
39) Lim, B.; Baek, B.; Jang, K.; Lee, N.K.; Lee, J.H.; Lee, Y.;
Kim, J.; Kang, S.W.; Park, J.; Kim, S.; Kang, N.W.;
Hong, S.; Kim, D.D.; Kim, I.; Hwang, H.; Lee, J.
Dyes Pigm. 2019, 169, 51–59. DOI: 10.1016/j.
dyepig.2019.05.008.
40) Wu, Z.Y.; Xu, Z.Y.; Tan, H.Y.; Li, X.; Yan, J.W.; Dong, C.Z.;
Zhang, L. Spectrochim. Acta Part A. 2019, 213, 167–175.
DOI: 10.1016/j.saa.2019.01.032.
(