A novel pyrazoline-based fluorescent probe for Cu2+ in aqueous solution and imaging in live cell

Article abstract of DOI:10.1016/j.inoche.2021.108612

In this study, a new pyrazoline derivate (1-acetyl-3- (2-hydroxy-1-naphthyl)-5-(2-phenyl-2H-chromene)-2-pyrazoline, N) is described as fluorescent probe for fluorometric detection of Cu²⁺. This fluorescence of probe has a high selectivity only toward Cu²⁺ ion in the other metal ions. It is remarkably observed that the fluorescence intensity of N decreased in the presence of Cu²⁺ ions with a strong capability to resist perturbations. The Limit of detection (LOD) value is calculated as 8.85 × 10^?7 M for Cu²⁺ while the complexation constant is calculated as 3.14 × 10⁵ M^?2 via fluorescence measurements. The interaction between of N and Cu²⁺ is reversible after adding PPi. The optimized calculation of the probe for Cu²⁺ is confirmed by TD-DFT calculations. N-Cu²⁺ is successfully applied in the intracellular imaging in living PK-21cells that will have a great chance for wide application.

Full text of DOI:10.1016/j.inoche.2021.108612

Inorganic Chemistry Communications 129 (2021) 108612
Contents lists available at ScienceDirect
Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Short communication
A novel pyrazoline-based fluorescent probe for Cu2+ in aqueous solution
and imaging in live cell
,
,
Ying-peng Zhanga *, Yu-chen Zhaoa, Qing-hua Xuea, Yun-shang Yanga *, Hui-Chen Guob,
Ji-Jun Xuec
a School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, China
b State Key Laboratory of Veterinary Etiological Biology and National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese
Academy of Agricultural Sciences, Lanzhou 730046, China
c State Key Laboratory of Applied Organic Chemistry & College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
A R T I C L E I N F O
A B S T R A C T
Keywords:
In this study, a new pyrazoline derivate (1-acetyl-3- (2-hydroxy-1-naphthyl)-5-(2-phenyl-2H-chromene)-2-pyr-
azoline, N) is described as fluorescent probe for fluorometric detection of Cu2+. This fluorescence of probe has a
high selectivity only toward Cu2+ ion in the2o+ther metal ions. It is remarkably observed that the fluorescence
intensity of N decreased in the presence of Cu ions with a strong capability to resist perturbations. The Limit of
detection (LOD) value is calculated as 8.85 × 10ꢀ 7 M for Cu2+ while the complexation constant is calculated as
3.14 × 105 Mꢀ 2 via fluorescence measurements. The interaction between of N and Cu2+ is reversible after adding
PPi. The optimized calculation of the probe for Cu2+ is confirmed by TD-DFT calculations. N-Cu2þ is successfully
applied in the intracellular imaging in living PK-21cells that will have a great chance for wide application.
Pyrazoline
Cu2+ fluorescent probe
Reversible recognition
Cell imaging
1. Introduction
in the detection and real-time monitoring of copper due to they are
typically irreversible and tend to be affected by many factors such as
Cu2+ plays critical function in living organisms, especially in the
process of cellular energy generation, free radical detocification,
oxygenic photosynthesis and signal transduction [1–4]. It plays an
indispensable role in the physiology and pathology process, since the
Cu2+ ion participates in various complexation of amino acids, enzyme
reactions and electron transduction as the co-factor of related enzymes
[5]. However, its insufficiency or excess load in the human body will
cause negative effects on human body, such as Alzheimer’s disease,
gastrointestinal disturbances, neurological disorders, and progression of
cancer [6–9]. So, selective and sensitive detection studies for Cu2+ are
quite important.
environmental conditions, instrumental efficiency, and probe concen-
trations [19]. Beyond that, among the various chemosensing techniques,
sensors based on a naked-eye response (colorimetric) have great atten-
tion since they do not depend on any expensive and specific instru-
mentation and can provide a selective, precise and sensitive method for
the detection of a target analyte [20,21]. So, it is an attractive and
challenging field development of new fluorometric sensors for the
detection of Cu2+ ion.
Pyrazoline derivatives are five-membered heterocyclic compounds
with excellent non-toxic bioactive compounds [22,23]. Therefore, they
have become a popular and important pharma core in medicinal
chemistry such as antibacterial, anticancer, antitumor, anti-
inflammatory and many other activities [24–28]. In addition to these
compounds have widely been used as fluorometric ion sensor, hole-
transport material in optoelectronic application with special fluores-
cence properties [29–31]. Recently, Li reported a dicyanomethylene-4H-
pyran-based fluorescence probe was designed for Cu2+ detection [4]. It
exhibited remarkable sensitivity and selectivity. Importantly, DCM-Cu
was successfully applied in the detection of Cu2+ in living cells with
In recent years, the detection of Cu2+ ions using a new fluorescence
probe is a greatly attractive research area due to fluorometric detection
is highly sensitive, the economy in addition to getting the response
rapidly and compared to traditional methods including atomic absorp-
tion spectrometry, chromatography, and plasma mass spectroscopy
[10–12]. Many fluorescence probes based on rhodamine, naph-
thalimide, coumarin, and tetraphenylethylene are widely used in the
detection of Cu2+ ion [13–18]. However, they have limited application
* Corresponding authors.
E-mail addresses: yingpengzhang@126.com (Y.-p. Zhang), yangyunshang@tom.com (Y.-s. Yang).
https://doi.org/10.1016/j.inoche.2021.108612
Received 6 February 2021; Received in revised form 6 April 2021; Accepted 6 April 2021
Available online 20 April 2021
1387-7003/© 2021 Elsevier B.V. All rights reserved.

Y.-p. Zhang et al.
Inorganic Chemistry Communications 129 (2021) 108612
Scheme 1. The synthetic route of Compound (N).
low cytotoxicity. While preparing the manuscript, Qian had synthesized
a fluorescent Au nanocluster LRL-AuNCs with RGDK-containing peptide
[32]. The LRL-AuNCs probe was used to detect copper ions in water
samples. Moreover, it has the advantages of low cytotoxicity and good
biocompatibility. These two pioneering research reports were particu-
larly encouraging for our work. However, these two probes are easily
affected by the surrounding environment and can’t do reversible
recognition, naked-eye recognition.
In the present study, we have been investigated the influences of
many kinds of metal ions on absorption and fluorescence properties of
the novel pyrazoline derivative compound N (Scheme 1) having the
chemical structure(1-acetyl-3- (2-hydroxy-1-naphthyl)-5-(2-phenyl-2H-
chromene)-2-pyrazoline) by using UV–Vis absorption and steady-state
fluorescence measurements. These obtained results exhibited that N is
a sensor with highly selective recognition behavior for the detection of
Cu2+ compared to the other relevant metal ions. As a Cu2+ selective
probe, this quenched fluorescence intensity can be used for the detection
of analytes [33,34]. Besides, the resulting N-Cu2þ compound reacts
specifically with pyrophosphate (PPi) anion through fluorescence
quenching. Furthermore, this probe was successfully applied for fluo-
rescent Cu2+ imaging in living cells and the color of compound N
changed significantly after interaction with Cu2+ from colorless to pale
yellow by naked-eye observation, indicating its value of practical
application in environment and biology.
Fig. 1. The fluorescence spectra of N in CH3CH2OH/H2O (1:1(v/v), HEPES =
10 mM, pH = 7.4) solution in the presence of various metal ions. (λex = 350
nm).). Insert: Photos of N (10 μM) in ethanol–water with and without addition
of Cu2+ (5 equiv.)
275 nm, the probe clearly showed strong fluorescence emission at 417
nm (Fig. 1). This strong fluorescence of probe N may be due to the C = N-
N isomerization with the pyrazoline fluorescent group. The experi-
mental results show that upon the addition of Cu2+ to the solution of
probe N, an obvious decrease in fluorescence intensity was observed.
Whereas, other metal ions have little effect on the fluorescence of the
system or have a very small fluorescence quenching effect.
2. Experimental
2.1. Chemicals and reagents
The details are in supporting information
The concentration of probe N was kept at 1.0 × 10ꢀ 5 M, and the
concentration of Cu2+ varied from 0 to 15.0 × 10ꢀ 5 M, and the UV
absorption curve was measured. As can be seen from Fig. 2, with the
increasing concentration of Cu2+, the absorbance in the range of
255–330 nm and 390–450 nm gradually increased and remained stable,
This may be due to the complexity of probe N with Cu2+ which affected
the structural change of probe molecule, resulting in the change of ab-
sorption peak in the UV absorption spectrum. There was a good linear
relationship between probe N absorbance and Cu2+ concentration
(Fig. 2(a)) at 425 nm. The linear regression equation y = 0.150x-0.0156,
R2 = 0.989 was obtained by fitting, as shown in Fig. 2(b). Moreover,
large changes in fluorescence intensity and obvious changes in fluores-
cence color during recognition make it possible to detect Cu2+ visually
(as shown in Fig. 2(c)). It showed that the color contrast of probe N and
probe N-Cu2+ in the solution under visible light, indicating that the
naked eye recognition effect can be realized during the interaction be-
2.2. Synthesis of compound N
The synthesis of compound N is as follows: 2-hydroxy-1-acetonaph-
thone is purchased from commercial suppliers. Compound 3 was pre-
pared according to literature method [36,37]. The details are in
supporting information.
2.3. Spectral test
The details are in supporting information
2.4. Cytotoxicity assay
The details are in supporting information
3. Results and discussion
tween probe N and probe N-Cu2+
.
3.1. Identification of copper ions by fluorescence and UV
In the CH3CH2OH/H2O system, under the excitation wavelength of
3.2. Fluorometric titration test of copper ion by probe
In order to solve the sensitivity of L to the Cu2+, the fluorescence
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Y.-p. Zhang et al.
Inorganic Chemistry Communications 129 (2021) 108612
Fig. 2. The UV absorption spectra of titration curve of probe N to Cu2+. (a) The change of absorbance of probe N (1.0 × 10ꢀ 5 M) with Cu2+; Inset: the nonlinear
fitting curve of N to Cu2+ at 425 nm and color responses in visible light. (b) A linear fitting plot of absorbance of probe N with Cu2+at 425 nm.
Fig. 3. The fluorescence spectra titration curve of probe N. (a) Fluorescence changes of N with different concentrations of Cu2+ in CH3CH2OH/H2O (1:1(v/v), HEPES
= 10 mM, pH = 7.4); (b) Fluorescence spectra of the probe N as a function of Cu2+ concentration.
Fig. 4. The fluorescence intensity of probe N was changed due to the change of
Cu2+ concentration at 417 nm.
Fig. 5. Fluorescence intensities of N in CH3CH2OH/H2O (1:1(v/v), HEPES =
10 mM, pH = 7.4) in the presence of various metal ions and further addition
of Cu2+
.
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Y.-p. Zhang et al.
Inorganic Chemistry Communications 129 (2021) 108612
coexisted with Cu2+. This shows that probe N has a high anti-
interference capability without affecting the fluorescence recognition
of Cu2+ under the interference of other metal cations. In addition, in
order to explore the influence of anions on the process of recognition of
Cu2+ by probe N, fluorescence spectrum experiments were conducted on
copper salts of sulfate, acetic acid, chloride and nitrate in CH3CH2OH/
H2O(1:1(V/V), HEPES = 10 mM, pH = 7.4) solution by probe N. The
concentration of various metal ions is 1.0 × 10ꢀ 2 mM. As can be seen
from Fig. 6, there was no significant change in fluorescence intensity in
the process of probe N identifying CuSO4, Cu(CH3COO)2⋅H2O, CuCl2 and
Cu(NO3)2.
In order to explore the practical application of probe N in a biological
environment at room temperature, the absorption spectrum character-
istics of probe N in a mixed solvent containing CH3CH2OH/H2O ((1:1, v/
v) for various metal ions were studied. As shown in Fig. 7a, without
adding Cu2+ ions, probe N showed a maximum absorption peak at 320
nm. Then, Cu2+ ions were added to the probe N. Cu2+ complexed with
probe N, causing the absorption peak to appear at 325 nm with a slight
redshift, and a new strong absorption peak appeared within the range of
390–450 nm It can be clearly seen from Fig. 7b that when adding
Fig. 6. Fluorescence spectra of N in CH3CH2OH/H2O (1:1(v/v), HEPES = 10
mM, pH = 7.4) in the presence of different copper salts.
Cu2+and other metal ions (Ag+, Al3+, Fe3+, Co2+, Ni2+, Ba2+, Ca2+
,
titration of N (10
μ
M) was performed with Cu2+ in ethanol–water (1:1
Cu2+, Cd2+, K+, Mg2+, Na+, Hg2+, Zn2+, Pb2+, Li+, Mn2+), only Cu2+
absorption peak has obvious changes. The addition of Fe3+ and Fe2+
(v/v)) solution (Fig. 3a). The Cu2+ ions concentration as the factor in-
creases, the fluorescence intensity of probe N decreases continuously
until it reaches saturation. The quantitative response of probe N to Cu2+
has a good linear relationship. The Benesi-Hildebrand [39] nonlinear
curve fits a straight line, showing a linear fit, and confirms that the
stoichiometric relationship between Cu2+and probe N is 1:1. From
Fig. 3b, we can conclude that the binding constant of the
Mꢀ Cu2+complex is 3.14 × 104 Mꢀ 1. As shown in Fig. 4, the linear
regression equation is y = 1.59879 + 0.26413x, R2 = 0.9298. The
Benesi-Hildebrand nonlinear curve fits a straight line, showing a linear
fit, and confirms that the stoichiometric relationship between Cu2+and
probe N is 1:1. The minimum detection limit is 8.85 × 10ꢀ 7 M (probe of
concentration 1 × 10ꢀ 5 M) according to the formula LOD = 3
σ/k (σ
denotes the 10 relative standard deviation fluorescence intensity of N).
3.3. Competitive and selective testings
The interference of coexisting ions is an important indicator of the
recognition performance of the probe. Therefore, the anti-interference
experiment was carried out. As shown in Fig. 5, the fluorescence in-
tensity of probe N was significantly quenched when various ions
Fig. 9. Job’s plot of N and Cu2+ complexation in CH3CH2OH/H2O(1:1(v/v),
HEPES = 10 mM, pH = 7.4).
Fig. 7. The UV absorption spectra of probe N. (a) The UV absorption spectra of N (1.0 × 10ꢀ 5 M) and N-Cu2+ in CH3CH2OH/H2O(1:1(v/v), HEPES = 10 mM, pH =
7.4) solution. (b) The UV absorption spectra of N in CH3CH2OH/H2O(1:1(v/v), HEPES = 10 mM, pH = 7.4) solution in the presence of various metal ions(1.0 ×
10ꢀ 2 mM).
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Inorganic Chemistry Communications 129 (2021) 108612
Fig. 10. 1H NMR spectra of N with Cu2+ in d-DMSO. a) Free probe N; b) Upon addition of 1.0 equiv. of Cu2+ to probe N; c) PPi to the mixed solution of N and
Cu2+;d).
Fig. 11. Possible complexation of probe N with Cu2+.
enhanced the overall absorption strength of probe N.
3.4. Reversibility and the proposed sensing mechanism
3.4.1. Possible complexation mechanism between probe N and Cu2+
In order to explore the stoichiometric ratio of complexation between
probe N and Cu2+, we carried out the Job’s Plot experiment. The total
concentration of probe N and Cu2+ was maintained at 1.0 × 10ꢀ 5m, the
Fig. 12. The change of fluorescence spectra of N-Cu2+ in CH3CH2OH/H2O(1:1
concentration ratio of the two was changed, and the fluorescence in-
(v/v), HEPES = 10 mM, pH = 7.4) upon addition of PPi.
tensity at 417 nm was measured respectively. It is concluded that when
the concentration ratio of Cu2+ in probe N and Cu2+ is 0.5 in the whole
hydroxyl group was involved in the reaction of probe N and Cu2+ in the
system, the minimum fluorescence intensity occurs (Fig. 9). It also in-
dicates that the complexation ratio of probe N and Cu2+ is 1:1. In
summary, combined with the recognition mechanism of some pyrazo-
line based fluorescent probes reported currently [40–44], it may be that
Cu2+ coordinates with nitrogen atoms and oxygen atoms on the corre-
sponding pyrazoline structure and oxygen atoms on the hydroxyl group
on the naphthene structure, leading to fluorescence quenching. In order
to further explore the coordination mode between probe and N and
binding process, and the complexation ratio was 1:1. While the PPi was
added, the probe N could be reused. We could infer the possible
complexation mode between probe N and Cu2+, as shown in Fig. 11.
3.4.2. PPI test fluorescence probe N detection Cu2+ reversibility experiment
In order to further understand the complexation behavior between
probe N and Cu2+, PPi(pyrophosphate) was added to the N-Cu2+ system
to study the effect of PPi on fluorescence signals. As the amount of PPi
was continuously added to the N-Cu2+ system, the fluorescence intensity
of probe N was restored (Fig. 12). The added PPi can eliminate Cu2+
from the complexed system with probe N. Because the complexation of
PPi and Cu2+ is much larger than that of probe N and Cu2+, thus making
Cu2+
,
1H NMR titration experiment was conducted (Fig. 10). It was
found that when Cu2+ was added to probe N, pyrazoline and the protons
on naphthalene showed the displacement of high or low field, and the
hydroxyl proton peak at 10.29 PPM decreased during the addition of
Cu2+. It almost disappears when adding 1.0 equivalent Cu2+. Thus, the
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Y.-p. Zhang et al.
Inorganic Chemistry Communications 129 (2021) 108612
Fig. 13. Optimized structures of N and N-Cu2+
.
Fig. 14. Frontier molecular orbital energy of N and N-Cu2+ at the excited state.
probe N free to recover its fluorescence intensity. This indicates that the
fluorescence attenuation of the N-Cu2+ system is caused by the
complexation of probe N and Cu2+, rather than the change of its
structure.
bonding interaction between C = N and C = O. Due to the addition of
Cu2+ in pyrazoline, the HOMO of N + Cu2+ is limited to this fragment,
and the CT from the electron donor to the electron acceptor group is
disturbed in N + Cu2+, leading to a decrease in fluorescence.
3.4.3. Optimized calculation
3.5. Imaging of intracellular Cu2+ and cell viability of the probe
The Gaussian 09 package of quantum chemistry [45] was used to
optimize the structure of N and N-Cu2+ with B3LYP/ 6-31g(d) [46–48],
and the structure of the probe molecule with the minimum energy was
optimized as shown in Fig. 13. TD-DET was used to calculate the excited
states of the above-optimized probe molecules, and their front-line
orbital energy and molecular transition energy were obtained. As
shown in Fig. 14, the energy difference of electrons from HOMO to
LUMO is 0.0764 eV after probe N is excited. In the N-Cu2+ molecule, it
was found that the addition of Cu2+ resulted in a reduction in the
HOMO-LUMO energy gap of the probe, and the energy level difference
was 0.0172 eV when the HOMO jumped to the LUMO orbital. By com-
parison, the reduction was 0.0592 eV. This is due to the hydrogen
The sensitivity of N for Cu2+ in living PK-21 cells was measured by
fluorescence microscopy. Fluorescence images of cells were obtained by
fluorescence microscope at 425 nm excitation wavelength and 5.0 nm
emission band. First, PK-21 cells incubated with the probe L indicated a
blue fluorescence image (Fig. 15(a)). The blue fluorescence was dis-
appeared after incubation of the probe N treated cells with Cu2+ (Fig. 15
(b)). The fluorescence images showed that the fluorescence signals were
located in the intracellular region which indicated that probe N had
great cell membrane permeability. After adding Cu2+, it was found that
the fluorescence intensity of the PK-21 cell nucleus decreased signifi-
cantly over time. Therefore, the fluorescence intensity signals were
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Y.-p. Zhang et al.
Inorganic Chemistry Communications 129 (2021) 108612
Fig. 15. Luminescence images of PK-21 cells. (a) PK-21 cells incubated with probe N (20
μ
mol/ L) for 30 min at 37 ◦C; (b) PK-21 cells incubated with probe N for 30
min and then further incubated with 30
μ
L Cu2+ for 30 min at 37 ◦C.
in cells under physiological condition and shows low toxicity. Moreover,
the binding mode and sensing mechanism of N with Cu2+ was proved by
theoretical calculations using Gaussian 09based on B3LYP/6-31G(d)
basis.
CRediT authorship contribution statement
Ying-peng Zhang: Conceptualization, Methodology, Supervision.
Yu-chen Zhao: Data curation, Writing - original draft. Qing-hua Xue:
Investigation. Yun-shang Yang: Investigation. Hui-Chen Guo: . Ji-Jun
Xue: Software.
Declaration of Competing Interest
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.
Appendix A. Supplementary data
Fig. 16. Cell viability graph of probe L using BK-21 cells by MTS assay.
Supplementary data to this article can be found online at https://doi.
org/10.1016/j.inoche.2021.108612.
changed the probe N which could be used to detect intracellular Cu2+
and sense the change of its concentration. It also provided a feasible
method and means to detect Cu2+ in the biological system in the future.
An MTS assay was used to detect cell viability. The viability rate of cells
References
[1] J.A. Cotruvo Jr, A.T. Aron, K.M. Ramos-Torres, C.J. Chang, Synthetic fluorescent
probes for studying copper in biological systems, Chem. Soc. Rev. 44 (2015)
4400–4414.
treated with the range of concentration 0–100 μM of N for 24 h was
shown in Fig. 16. The probe N was found to be the least toxic to the cells.
[2] Y.H. Zhao, Y.Y. Luo, H. Wang, H.P. Wei, T. Guo, H.L. Tan, L. Yuan, X.B. Zhang,
A novel ratiometric and reversible fluorescence probe with a large Stokes shift for
Cu2+ based on a new clamp-on unit, Anal. Chim. Acta. 1065 (2019) 134–141.
[3] A. Thangaraj, V. Bhardwaj, S.K. Sahoo, A multi-analyte selective dansyl derivative
for the fluorescence detection of Cu (ii) and cysteine, Photoch Photobio Sci. 18
(2019) 1533–1539.
4. Conclusion
In summary, a novel fluorescent probe based on naphthyl-pyrazoline
for Cu (II) ions recognition was designed and synthesized. It showed that
the probe N in the mixed solution has high selectivity, sensitivity and
anti-interference abilities which were observed by the ultraviolet ab-
sorption spectrum and fluorescence spectrum in the ethanol–water
system. The complexation of probe N and Cu2+ is a reversible process
and can be recognized by naked eyes. The blinding constant of the N-
Cu2þ complex was found to be Ka = 3.14 × 104 Mꢀ 1 and the limit of
detection is 8.85 × 10ꢀ 7 M. The probe N has been used for imaging Cu2+
[4] Z. Li, Y.Q. Xu, H.D. Xu, M.Y. Cui, T.G. Liu, X.Y. Ren, J.F. Sun, D.W. Deng, Y.Q. Gu,
M. Wang, A dicyanomethylene-4H-pyran-based fluorescence probe with high
selectivity and sensitivity for detecting copper (II) and its bioimaging in living cells
and tissue, Spectrochim Acta A. 244 (2020), 118819.
[5] A. Chafik, A. Essamadi, S.Y. Çelik, A. Mavi, Purification and biochemical
characterization of a novel copper, zinc superoxide dismutase from liver of camel
(Camelus dromedarius): An antioxidant enzyme with unique properties, Bioorganic
Chem. 86 (2019) 428–436.
[6] C.M. Ackerman, C.J. Chang, Copper signaling in the brain and beyond, J. Biol.
Chem. 293 (2018) 4628–4635.
7

Y.-p. Zhang et al.
Inorganic Chemistry Communications 129 (2021) 108612
[7] T. Xiao, C.M. Ackerman, E.C. Carroll, S. Jia, A. Hoagland, J. Chan, B. Thai, C.S. Liu,
E.Y. Isacoff, C.J. Chang, Copper regulates rest-activity cycles through the locus
coeruleus-norepinephrine system, Nat. Chem. Biol. 14 (2018) 655–663.
[8] X.F. Tan, Y. Zhou, P. Gong, H.F. Guan, B.C. Wu, L. Hou, X.M. Feng, W. Zheng, J. Li,
A multifunctional bis-(ꢀ )-nor-meptazinol-oxalamide hybrid with metal-chelating
property ameliorates Cu (II)-induced spatial learning and memory deficits via
preventing neuroinflammation and oxido-nitrosative stress in mice, J. Trace Elem.
Med. Bio. 52 (2019) 199–208.
carbonic anhydrase and acetylcholinesterase inhibitors with low cytotoxicity,
Bioorg. Chem. 84 (2019) 511–517.
[26] H.I. Gul, C. Yamali, H. Sakagami, A. Angeli, J. Leitans, A. Kazaks, K. Tars, D.
O. Ozgun, C.T. Supuran, New anticancer drug candidates sulfonamides as selective
hCA IX or hCA XII inhibitors, Bioorg. Chem. 77 (2018) 411–419.
[27] S. Kuthyala, M. Hanumanthappa, S.M. Kumar, S. Sheik, N.G. Karikannar,
A. Prabhu, Crystal, Hirshfeld, ADMET, drug-like and anticancer study of some
newly synthesized imidazopyridine containing pyrazoline derivatives, J. Mol.
Struct. 1197 (2019) 65–72.
[9] S.C. Wang, Z.H. Sheng, Z.G. Yang, D.H. Hu, X.J. Long, G. Feng, Y.B. Liu, Z. Yuan, J.
J. Zhang, H.R. Zheng, Activatable Small-Molecule Photoacoustic Probes that Cross
the Blood-Brain Barrier for Visualization of Copper (II) in Mice with Alzheimer’s
Disease, Angew. Chem. Int. Edit. 58 (2019) 12415–12419.
[28] A.V. Chate, A.A. Redlawar, G.M. Bondle, A.P. Sarkate, S.V. Tiwari, D.K. Lokwani,
A new efficient domino approach for the synthesis of coumarin-pyrazolines as
antimicrobial agents targeting bacterial d-alanine-d-alanine ligase, New J. Chem.
43 (2019) 9002–9011.
[10] Y.F. Huang, J.H. Peng, X.J. Huang, Allylthiourea functionalized magnetic
adsorbent for the extraction of cadmium, copper and lead ions prior to their
determination by atomic absorption spectrometry, Microchim. Acta. 186 (2019)
51.
[29] G. Subashini, R. Shankar, T. Arasakumar, P.S. Mohan, Quinoline appended
pyrazoline based Ni sensor and its application towards live cell imaging and
environmental monitoring, Sens. Actuat. B-Chem. 243 (2017) 549–556.
[30] A. Karuppusamy, P. Kannan, Bluish green emission from pyrene-pyrazoline
containing heterocyclic materials and their electronic properties, Journal of
Luminescence. 194 (2018) 718-728.
[11] Z. Wei, S. Sandron, A. Townsend, P. Nesterenko, B. Paull, Determination of trace
labile copper in environmental waters by magnetic nanoparticle solid phase
extraction and high-performance chelation ion chromatography, Talanta. 135
(2015) 155–162.
[31] E. Bozkurt, H.I. Gul, A novel pyrazoline-based fluorometric “turn-off” sensing for
Hg2+, Sens. Actuat. B-Chem. 255 (2018) 814–825.
[12] R.J. Wang, L.W. Zhang, R. Liu, L. Liu, J.M. Yao, Ultra-fast and probe-free cellulose
biosensor for visual detection of Cu2+ ions in biological samples, Carbohyd. Polym.
223 (2019), 115117.
[32] D. Qian, Z. Wang, Z.X. Xiao, C.J. Fang, A fluorescent probe for the detection of Cu
(II) in water and tumor cells, Inorg. Chem. Commun. 126 (2021), 108471.
[33] N. Ahmed, W. Zareen, D. Zhang, X.P. Yang, Y. Ye, Coumarin-Based Reversible
Fluorescent Probe for Selective Detection of Cu2+ in Living Cells, J. Fluoresc. 30
(2020) 1171–1179.
[13] Y. Tang, Y.Y. Li, J. Han, Y.L. Mao, L. Ni, Y. Wang, A coumarin based fluorescent
probe for rapidly distinguishing of hypochlorite and copper (II) ion in organisms,
Spectrochim. Acta A. 208 (2019) 299–308.
[14] D. Vashisht, K. Kaur, R. Jukaria, A. Vashisht, S. Sharma, S. Mehta, Colorimetric
chemosensor based on coumarin skeleton for selective naked eye detection of
cobalt (II) ion in near aqueous medium, Sens. Actuat. B-Chem. 280 (2019)
219–226.
[34] J. Zhang, M.Y. Chen, C.B. Bai, R. Qiao, B. Wei, L. Zhang, R.Q. Li, C.Q. Qu,
A Coumarin-Based Fluorescent Probe for Ratiometric Detection of Cu2+ and Its
Application in Bioimaging, Front Chem. 8 (2020) 800.
[36] K.V. Sashidhara, S.R. Avula, P.K. Doharey, L.R. Singh, V.M. Balaramnavar,
J. Gupta, S. Misra-Bhattacharya, S. Rathaur, A.K. Saxena, J.K. Saxena, Designing,
synthesis of selective and high-affinity chalcone-benzothiazole hybrids as Brugia
malayi thymidylate kinase inhibitors: in vitro validation and docking studies, Eur.
J. Med. Chem. 103 (2015) 418–428.
[15] D.Y. Liu, Y.J. Wang, R.N. Wang, B.C. Wang, H.X. Chang, J.T. Chen, G.M. Yang, H.
R. He, Fluorescein-based fluorescent sensor with high selectivity for mercury and
its imaging in living cells, Inorg. Chem. Commun. 89 (2018) 46–50.
[16] D.S. Lim, S.Y. Park, K.S. Hwang, S.K. Chang, Colorimetric determination of Hg2+
via thiosemicarbazide-to-oxadiazole transformation of a coumarin-benzopyrylium
dye, Tetrahedron Lett. 59 (2018) 1819–1822.
[37] J. Li, X.P. Yang, D. Zhang, Y.X. Liu, J. Tang, Y.F. Li, Y. Zhao, Y. Ye, A fluorescein-
based “turn-on” fluorescence probe for hypochlorous acid detection and its
application in cell imaging, Sens. Actuat. B-Chem. 265 (2018) 84–90.
[39] Y. Shiraishi, S. Sumiya, Y. Kohno, T. Hirai, A rhodamineꢀ cyclen conjugate as a
highly sensitive and selective fluorescent chemosensor for Hg (II), J. Org. Chem. 73
(2008) 8571–8574.
[17] L. Lu, X.K. Ren, R. Liu, X.Q. Jiang, L.Y. Geng, J.F. Zheng, Y.K. Feng, E.Q. Chen,
Ionic Self-Assembled Derivative of Tetraphenylethylene: Synthesis, Enhanced
Solid-State Emission, Liquid-Crystalline Structure, and Cu2+ Detection Ability,
Chemphyschem. 18 (2017) 3605–3613.
[18] R.Q. Zhang, F.Y. Yan, Y.C. Huang, D.P. Kong, Q.H. Ye, J.X. Xu, L. Chen,
Rhodamine-based ratiometric fluorescent probes based on excitation energy
transfer mechanisms: construction and applications in ratiometric sensing, RSC
Adv. 6 (2016) 50732–50760.
[40] Y.S. Yang, B.X. Cao, Y.P. Zhang, Y.Y. Dong, Bispyrazoline Fluorescent Probe for the
Recognition of Cu~(2+) and Zn~(2+) with Different Fluorescence, Chin. J. Org.
Chem. 37 (2017) 11.
[41] L. Firoozpour, N. Edraki, M. Nakhjiri, S. Emami, M. Safavi, S.K. Ardestani,
M. Khoshneviszadeh, A. Shafiee, A. Foroumadi, Cytotoxic activity evaluation and
QSAR study of chromene-based chalcones, Arch. Pharm. Res. 35 (2012)
2117–2125.
[19] H.H. Deng, X.Y. Fang, K.Y. Huang, S.B. He, H.P. Peng, X.H. Xia, W. Chen,
Regulation of metal ion selectivity of fluorescent gold nanoclusters by
metallophilic interactions, Anal. Chim. Acta. 1088 (2019) 116–122.
[20] J.N. Dai, C.G. Ma, P. Zhang, Y.Q. Fu, B.X. Shen, Recent progress in the
development of fluorescent probes for detection of biothiols, Dyes Pigments. 177
(2020), 108321.
´
[42] M. Rodríguez-Caceres, R. Agbaria, I. Warner, Fluorescence of metal–ligand
complexes of mono-and di-substituted naphthalene derivatives, J. Fluoresc. 15
(2005) 185–190.
[21] L. Ding, X. Li, L.C. Hu, Y.C. Zhang, Y. Jiang, Z.P. Mao, H. Xu, B.J. Wang, X.L. Feng,
X.F. Sui, A naked-eye detection polyvinyl alcohol/cellulose-based pH sensor for
intelligent packaging, Carbohyd. Polym. 233 (2020), 115859.
[43] C.X. Yuan, S.Y. Li, Y.B. Wu, L.P. Lu, J.Y. Miao, M.L. Zhu, Zn (II)-selective and
sensitive fluorescent chemosensor based on steric constrains and inhibition of
ESIPT, Sens. Actuat. B-Chem. 242 (2017) 1035–1042.
´
[22] J. Orrego-Hernandez, J. Cobo, J. Portilla, Synthesis, photophysical properties, and
[44] X.Q. Li, Z. Zhou, C.C. Zhang, Y.H. Zheng, J.W. Gao, Q.M. Wang, Ratiometric
fluorescence platform based on modified silicon quantum dots and its logic gate
performance, Inorg. Chem. 57 (2018) 8866–8873.
metal-ion recognition studies of fluoroionophores based on 1-(2-pyridyl)-4-
styrylpyrazoles, ACS omega. 4 (2019) 16689–16700.
[23] A. Tigreros, J. Portilla, Recent progress in chemosensors based on pyrazole
derivatives, RSC Adv. 10 (2020) 19693–19712.
[45] M. Frisch, G. Trucks, H. Schlegel, G. Scuseria, M. Robb, J. Cheeseman, G. Scalmani,
V. Barone, G. Petersson, H. Nakatsuji, Gaussian 16, Gaussian, Inc., Wallingford, CT,
2016.
[24] A. Palanimurugan, A. Kulandaisamy, DNA, in vitro antimicrobial/anticancer
activities and biocidal based statistical analysis of Schiff base metal complexes
derived from salicylalidene-4-imino-2, 3-dimethyl-1-phenyl-3-pyrazolin-5-one and
2-aminothiazole, J. Organomet. Chem. 861 (2018) 263–274.
[46] A.D. Becke, Density-functional exchange-energy approximation with correct
asymptotic behavior, Phys. Rev. A. 38 (1988) 3098.
[47] A.D. Becke, Density-functional thermochemistry. I. The effect of the exchange-only
gradient correction, J. Chem. Phys. 96 (1992) 2155–2160.
[25] D.O. Ozgun, H.I. Gul, C. Yamali, H. Sakagami, I. Gulcin, M. Sukuroglu, C.
T. Supuran, Synthesis and bioactivities of pyrazoline benzensulfonamides as
[48] C. Lee, W.T. Yang, R.G. Parr, Development of the Colle-Salvetti correlation-energy
formula into a functional of the electron density, Phys. Rev. A. 37 (1988) 785.
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