A highly selective coumarin-based chemosensor for the sequential detection of Fe3+ and pyrophosphate and its application in living cell imaging

Article abstract of DOI:10.1016/j.tetlet.2018.04.007

A new chemosensor based on coumarin FB has been designed and synthesized for the detection of Fe³⁺ and PPi. FB displayed a high affinity to Fe³⁺ in the presence of other competing cations. The resulting FB-Fe³⁺ complex displayed highly sensitivity to PPi via Fe³⁺ displacement approach. The Fe³⁺ and PPi recognition processes is rapid and reversible, the detection limits of FB to Fe³⁺ and FB-Fe³⁺ complex to PPi were estimated to be 8.73 × 10^?8 M and 1.25 × 10^?8 M, respectively. The good biocompatibility of FB enables the investigation of fluorescent response for Fe³⁺ and PPi in living cells by confocal microscope. A B3LYP/6-31G(d,p) basis set was employed for optimization of FB and FB-Fe³⁺ complex.

Full text of DOI:10.1016/j.tetlet.2018.04.007

Accepted Manuscript
A highly selective coumarin-based chemosensor for the sequential detection of
3
+
Fe and pyrophosphate and its application in living cell imaging
Wei Wang, Jian Wu, Qinglei Liu, Yan Gao, Huimin Liu, Bing Zhao
PII:
S0040-4039(18)30438-6
https://doi.org/10.1016/j.tetlet.2018.04.007
TETL 49870
DOI:
Reference:
To appear in:
Tetrahedron Letters
Received Date:
Revised Date:
Accepted Date:
1 February 2018
29 March 2018
3 April 2018
Please cite this article as: Wang, W., Wu, J., Liu, Q., Gao, Y., Liu, H., Zhao, B., A highly selective coumarin-based
3
+
chemosensor for the sequential detection of Fe and pyrophosphate and its application in living cell imaging,
Tetrahedron Letters (2018), doi: https://doi.org/10.1016/j.tetlet.2018.04.007
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Tetrahedron Letters
journal h omepage: www.els evier. com
3+
A highly selective coumarin-based chemosensor for the sequential detection of Fe
and pyrophosphate and its application in living cell imaging
a
a
a
b,
a,
c
Wei Wang , Jian Wu , Qinglei Liu , Yan Gao *, Huimin Liu *, Bing Zhao
a School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai 201418, China
b China Department of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China
c Chemistry and Chemical Engineering Institute, Qiqihar University, Qiqihar 161006, China
ARTICLE INFO
AB S TR AC T
Article history:
Received
Received in revised form
Accepted
A new chemosensor based on coumarin FB has been designed and synthesized for the detection
3+
3+
of Fe and PPi. FB displayed a high affinity to Fe in the presence of other competing cations.
3
+
3+
The resulting FB-Fe complex displayed highly sensitivity to PPi via Fe displacement
3+
approach. The Fe and PPi recognition processes is rapid and reversible, the detection limits of
Available online
3+
3+
-8
-8
FB to Fe and FB-Fe complex to PPi were estimated to be 8.73×10 M and 1.25×10 M,
respectively. The good biocompatibility of FB enables the investigation of fluorescent response
Keywords:
Coumarin
Chemosensor
Iron
3+
for Fe and PPi in living cells by confocal microscope. A B3LYP/6-31G (d, p) basis set was
3+
employed for optimization of FB and FB-Fe complex.
PPi
Bioimaging
2
013 Elsevier Ltd. All rights reserved.
Introduction
detection of PPi has also been considered to be desirable in
2
2
cancer research. In addition, rheumatism disorders resulting
from dehydration of calcium pyrophosphate23-2c6rystals in
Fluorescent probes display a significant change in optical
signal when selectively sensing the chemical and biological guest
connective tissue have become an important issue.
Thus, the
1-5
species. Iron is an essential metal ion that plays a vital role in
living systems at the cellular level. Many proteins and enzymes
use iron as a cofactor in a wide range of physiological processes,
such as electron transport, oxygen transport, and oxidoreductase
fluorescence-based chemosensing of PPi has been one of the
main focuses among different sensing studies. (delete)
Given its important physiological role, it is imperative to
27
achieve quantitative determination of PPi. Over the past few
6
3+
catalysis. Abnormal levels of Fe may cause serious adverse
years, several research groups have studied methods for
identifying phosphates, including the conventional malachite
7
,8
effects and diseases. Deficiency of iron reduces oxygen
delivery to cells, resulting in exhaustion, decreased immunity and
permanent loss of motor skills. Conversely, high levels of iron
within the body are associated with increased incidence of certain
cancers and dysfunction of certain organs, such as the heart,
pancreas, and liver.
diseases, such as Alzheimer’s, Huntington’s, and Parkinson’s
disease, which is responsible for some neural disorders.
Therefore, considerable effort has been devoted to the
development of novel fluorescence probe for Fe detection,
especially under physiological conditions.
green assay method, chromogenic, bioluminescence assay,
9
28-31
electrochemical and fluorescent chemosensors.
Among them,
fluorescent chemosensors are more attractive because of their
32
good selectivity, high sensitivity, simplicity and stability.
1
0,11
Recently, spiropyran-based fluorescent sensors have emerged to
detect urinary pyrophosphate and nucleic acid based fluorescent
Excessive iron can also cause serious
33, 34
probe to monitor PPi in urine and cell lysates.
1
2,13
Recently, one of the most frequently employed strategies for
anion sensing is the use of metal complexes following the
changes in their optical properties after the formation of metal-
3+
14-16
35-37
assisted strong covalent interactions with the target species.
Likewise, anions play an important role in a wide range of
biological and chemical processes, and the development of probe
for detecting biologically significant anions is a growing research
The fluorophore-metal complex is nonfluorescent owing to the
ion-induced fluorescence quenching. The anion binding to the
metal center will displace the neutral ligand, altering or restoring
17
topic. Amongst the anions, the detection of the important
38
its spectroscopic behavior. In this work, considering the
4
-
pyrophosphate (P
involved in a range of bioenergetic and metabolic processes, such
2
O
7
, PPi) is particularly important as it is
3+
fluorescence quenching properties of Fe and the advantage of
3+
high Fe -PPi affinity, we may reasonably expect to design a new
as gene d8,u19plication, gene transcription, and signal
3+
fluorescence chemosensor for Fe
and PPi based on
1
transduction,
and its detection is being investigated as a real-
displacement approach. Herein, a convenient chemosensor FB
based on coumarin was facilely designed and synthesized
2
0,21
time DNA sequencing method.
Most importantly, the

2
(
Scheme 1), which exhibits a rapid, selective, sensitive “on-off”
3+
fluorescence response to Fe . In the presence of PPi, the
3+
3+
decomplexing of Fe on FB-Fe complex led to a fluorescence
restoration. The reversible “on-off-on” fluorescence probe in
neutral buffered media showed the good application in live Hep
G2 cell imaging.
Results and discussion
Fig.1. (a) Changes in the emission spectra of FB (10 μM) in the
presence of different metal ions (20 μM) in HEPES buffer (DMSO:
The synthetic route for compound FB was shown in Scheme 1.
Compound 7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde
H O =3:7, 20 mM, pH=7.2); (b) Fluorescence response of FB (10 μM)
2
3+
to Fe (20 μM) in the presence of other common metal ions (20 μM).
The red bars represent the enhancement degree of FB in the presence of
cations of interest (all are 20 μM). The green bars represent the changes
39
(
2) were prepared according to the literature method. The structure
of FB was confirmed by NMR, mass spectra, IR and elemental
analysis (Fig.S1-S4). The detailed experimental procedures and
the characterization of the compound FB were described in the
3+
of the emission that occurs upon the subsequent addition of Fe (20
μM) to the above solution (λex=335 nm)
.
3+
In order to further evaluate the Fe -responsive properties of
FB, fluorescence titrations of different concentrations of Fe
were performed. As shown in Fig. 2, upon the addition of Fe to
40
3+
experimental section. The spectral data were in agreement with
the desired structures.
3+
FB, fluorescence intensity decreased gradually and was saturated
3+
with 1 equiv of Fe , indicating a complete complex formation of
3+
FB and Fe . Job plot was utilized to determine the binding
3+
stoichiometry of the FB-Fe complex. It revealed that FB and
3
+
42
Fe formed a complex in 1:1 stoichiometry (Fig. S7).
According to linear Benesi-Hildebrand expression, the
fluorescence intensity [1/ (F -F)] of FB at 447 nm varied as a
0
3+
43
function of 1/[Fe ] in a linear relationship (R2=0.9949), the
3+
association constant of FB with Fe was calculated to be 1.35×
5
–1
3+
1
0
0 M (Fig. S8). The fluorescence changes (F -F) vs. Fe
concentration were displayed in Fig. S9, the result revealed a
Scheme 1. Synthesis of the fluorescence chemosensor FB
3+
good linearity of the common ΔF vs. [Fe ] from 0 to 10 μM (R2
3
+
UV-vis and Fluorescence recognition of Fe
In order to check the binding behavior of FB with different
–8
=
0.9954). The limit of detection was estimated to be 8.73×10
44
M based on reported method defined by IUPAC.
3
+
+
2+
2+
2+
+
2+
2+
2+
2+
metal ions (Cr , Ag , Co , Cu , Hg , K , Fe , Ni , Cd , Pb ,
2+
2+
3+
2+
2+
+
Ba , Mg , Al , Ca , Zn and Na ), metal binding test of FB
was investigated by the UV-vis and fluorescence emission
spectroscopy. All spectroscopic measurements were performed at
about 25℃.
The binding behavior of receptor FB towards various metal
ions was examined by means of fluorescence spectroscopy in
2
HEPES buffer solution (DMSO:H O=3:7, 20mM, pH=7.2). As
presented in Fig. 1a, receptor FB alone has a very strong
fluorescence emission with an excitation of 335 nm, the addition
3+
of Fe created a remarkable fluorescence quenching (15-fold),
Fig.2. Fluorescence spectra of FB (10 μM) in HEPES buffer solution
3
+
+
2+
whereas the addition of other metal ions such as Cr , Ag , Co ,
(DMSO: H O = 3:7, 20 mM, pH = 7.2) in the presence of different
2
2
+
2+
+
2+
2+
2+
2+
2+
2+
3+
2+
3+
Cu , Hg , K , Fe , Ni , Cd , Pb , Ba , Mg , Al , Ca ,
amounts of Fe (0-20 μM). Inset: The quenching rate of the emission
2
+
+
3+
intensities of FB (10 μM) at 447 nm as a function of Fe (0-20 μM)
Zn and Na to the solution FB exhibited no decrease in the
emission intensity. Consistent with the fluorescent spectra, the
emission color can be clearly observed to change from blue to
(
λex=335 nm).
The UV-vis absorption property of probe FB (10 μM) in
3
+
2
DMF/H O HEPES buffer (v/v = 3:7, pH = 7.2) was investigated
colorless under UV light in presence of Fe , indicating that there
will be some interaction between FB and Fe . This “ON-OFF”
3+
(Fig. 3). Free sensor FB showed an absorption band at 350 nm,
3+
switching mechanism could be ascribed to the paramagnetic
upon adding 1 equiv of Fe , the absorption intensity was
significantly enhanced, (Fig. 3), attributing to the formation of a
3+
quenching effect of Fe and/or ligand to metal charge transfer
41
3+
45
(
LMCT). Undoubtedly, the high selectivity should be preferred
FB-Fe ensembles, However, the addition of other interested
metal ions did not produce any significant absorption spectrum
changes of sensor FB. This result suggested that sensor FB could
choice for excellent sensor, so the selectivity and anti-
interference performance of the probe FB in the presence of
various metal ions were further studied (Fig. 1b). The addition of
3+
3+
serve as a highly selective sensor for Fe in neutral buffered
Fe (20 μM) to the solutions of FB (10μM) with interfering
3
+
+
2+
2+
2+
+
2+
media.
cations (20 μM) such as Cr , Ag , Co , Cu , Hg , K , Fe ,
2
+
2+
2+
2+
2+
3+
2+
2+
+
UV-vis absorption spectra of FB in the presence of different
Ni , Cd , Pb , Ba , Mg , Al , Ca , Zn and Na
appeared a significant fluorescence quenching which were
similar to that caused by Fe only. These results indicated that
the coexisting metal ion had a negligible effect on the emission
intensity of the complexation.
3+
concentrations of Fe were further studied in HEPES buffer
3
+
3+
solution (Fig. S10). When Fe (0-20 μM) ion was gradually
introduced into a solution of 10 μM FB in HEPES buffer, the
intensity of absorption band significantly increased, indicating
3+
the specific absorbance respond by Fe ions.

3
+
Fig.5. Normalized fluorescence spectra of FB-Fe (10 μM) in HEPES
buffer solution (DMSO: H O=3:7, 20 mM, pH=7.2) in the presence of
2
-
4
different amounts of PPi (2×10 M) (λex=335 nm).
Fig.3. Absorption spectra of FB (10 μM) in HEPES buffer solution
DMSO: H O=3:7, 20 mM, pH=7.2) upon addition of various metal
(
2
ions (20 μM).
Spectral recognition of PPi by FB-Fe
3
+
3+
Due to the extremely high affinity of Fe -PPi, it is
3+
Fig.6. The linear responses of FB (10 μM) versus low concentration PPi
conceivable that the binding of PPi to the Fe center will
displace the neutral ligand and thus change or restore its
(
0-100 μM) at 447 nm in HEPES buffer solution (DMSO:H
2
O=3:7, 20
mM, pH=7.2). Excitation was performed at 335 nm.
3+
spectroscopic behavior, the respond of FB-Fe complex towards
The response time of the reaction system was studied to
various anions and nucleotides were then evaluated. In accord
3+
3+
evaluate the sensitivity of FB towards Fe and FB-Fe towards
PPi. As shown in Fig. S11, the fluorescence of FB rapidly
3
+
with the expectation, the fluorescence of FB-Fe
was
dramatically enhanced with the addition of 2×10 M PPi (Fig.
a). Whereas, the addition of other anions and polyphosphate
-4
3+
quenched after Fe (20 μM) was added, reached its minimum
4
value in 40 seconds and stabilized thereafter, as shown in Fig.
–
–
–
–
–
–
4
–
2
–
species such as Ac , Br , Cl , F , SCN , HSO
, NO
, HCO
3
,
3+
S10(a). Meanwhile, the fast fluorescence responses of FB-Fe
2–
2–
2–
CO , SO , S , ADP, AMP, ATP and pyrophosphate (Pi) to
FB-Fe solution did not produce any discernible fluorescence
spectra changes. In addition, to evaluate the practicability of FB-
Fe as a fluorescent chemosensor for the detection of PPi in
complicated environment, competition experiments were
3 4
towards PPi was also confirmed by the addition of PPi (200 μM)
3+
3+
to the solution of FB-Fe (10 μM) in HEPES buffer. As shown
in Fig. S10(b), upon the addition of PPi, a significant
fluorescence response could be observed within 50 s, indicating
3+
3+
that the FB-Fe system could be used for the real-time detection
3+
conducted for examining the selectivity of FB-Fe complex
towards PPi in the presence of different anions and
polyphosphate species. As shown in Fig. 4b, all the chosen
competitive anions showed no influence on the fluorescence
detection of PPi, suggesting that FB-Fe has a high selectivity
for PPi even in the presence of competing anions.
of PPi.
In order to investigate the sensitivity of the absorption
intensities to PPi concentration, absorption titrations was further
conducted by the addition of increasing amount of PPi into the
3+
3+
buffer solution of FB-Fe . As shown in Fig. 7, upon the addition
–4
3+
of PPi (0-2×10 M) to a solution of FB-Fe , the absorption
intensity at 350nm increased gradually and the final absorption
spectra was in agreement with the free chemosensor FB,
indicating the results of the decomplexation of Fe in the
presence of PPi. However, in the presence of other physiological
3
+
–
–
–
–
and environmental important anions, such as Ac , Br , Cl , F ,
–
–
–
–
2–
2–
2–
4 2 3 3 4
SCN , HSO , NO , HCO , CO , SO , S , and adenosine
phosphate series, such as ADP, AMP, ATP and Pi, no obvious
changes on absorption spectra could be observed (Fig. 8),
suggesting the high selectivity of FB-Fe towards PPi.
3
+
Fig.4. (a) Changes in the emission spectra of FB-Fe (10 μM) in the
-
4
3+
presence of different anions (2×10 M) in HEPES buffer (DMSO :
O=3:7, 20 mM, pH=7.2); (b) Normalized fluorescence response of
FB-Fe (10 μM) in the presence of various analytes (2×10 M): (1)
H
2
3
+
-4
–
2–
–
–
–
–,
–
2–
NO
,
(
2
, (2) S , (3) F , (4) SCN , (5) Ac , (6) HCO
3
(7) HSO
4 3
, (8) CO
–
–
2–
(9) Cl , (10) Br , (11) SO
16) PPi λex=335 nm
4
, (12) AMP, (13) ADP, (14) ATP, (15) Pi,
(
).
To investigate the sensitivity of the fluorescence intensities of
3+
the FB-Fe to the concentration of PPi, fluorescence titration
was carried out in HEPES buffer solution. As shown in Fig. 5,
3+
upon addition of PPi into FB-Fe solution, the fluorescence
intensity increased gradually with the increase of the
concentration of PPi, and then reached the maximum values at
about 10 equiv of PPi, which is essentially identical with the
emission wavelength3 of free FB, indicating that the
3
+
Fig.7. UV-vis absorption spectra of FB-Fe (10 μM) in HEPES buffer
solution (DMSO:H O=3:7, 20 mM, pH=7.2) in the presence of different
amounts of PPi (0-2×10 M).
2
–4
+
decomplexation of Fe by PPi. The detection limit for PPi
anions, calculated according to the reported method defined by
-8
46
3+
IUPAC is 1.25×10 M (Fig. 6), demonstrating that FB-Fe has
high sensitivity for the fluorescence sensing of PPi in buffer
solution.
3
+
Fig.8. Absorption spectra of FB-Fe (10 μM) in HEPES buffer solution
DMSO: H O=3:7, 20 mM, pH =7.2) in the presence of all kinds of
analytes (2×10 M): (1) NO
(
2
–
4
–
2–
–
–
–
2
, (2) S , (3) F , (4) SCN , (5) Ac , (6)
– – 2–
–
,
–
2–
HCO
3
4 3 4
(7) HSO , (8) CO , (9) Cl , (10) Br , (11) SO , (12) AMP,
(
13) ADP, (14) ATP, (15) Pi, (16) PPi.

4
FB-Fe3+
FB
Fluorometric titration assays detected the reversible detection
of PPi. As shown in Fig. 9, “ON-OFF-ON” fluorescence changes
3+
were observed by the alternative additions of Fe and PPi to the
solution of FB. The fluorescence changes were almost reversible
even after several cycles with the sequentially alternative
LUMO (-2.69eV)
3.11eV
LUMO (-2.84eV)
2.62eV
3
+
addition of Fe and PPi, indicating that FB can be developed as
3+
a reversible fluorescence ON-OFF-ON chemosensor for Fe and
PPi.
HOMO (-5.80eV)
HOMO (-5.46eV)
3
+
Fig. 10. Energy diagram of HOMO and LUMO orbital FB and FB-Fe
complex
MTT assay
The cytotoxicity of FB towards the Hep G2 cells was
investigated by the reduction activity of the methyl thiazolyl
tetrazolium (MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetr-
azoliumbromide]) assay. As shown in Fig. S12, following
incubation of FB (2-16 μM) with Hep G2 cells for 24 h at 37 ℃,
no significant change in the proliferation of Hep G2 cells was
observed. Even after incubation with 10 μM FB for 24 h, the
cellular viability remained above 90%, indicating that FB is
biocompatible and suitable for fluorescence imaging in living
cells. The results revealed that FB is low cytotoxicity both at low
and high concentration and will not kill the Hep G2 cells being
probed.
Fig.9. (a) Fluorescence spectral changes of FB (10 μM) after the
3
+
sequential addition of Fe
DMSO:H O=3:7, 20 mM, pH=7.2).(b)Reversible changes in
fluorescence intensity of FB (10 μM) after the sequential addition of
and PPi in HEPES buffer solution
(
2
3
+
Fe and PPi.
3
+
The plausible mechanism of FB towards Fe and PPi
The proposed displacement strategy for the PPi detection was
further supported by the results of mass spectra studies, FT-MS
+
+
spectra of FB showed a molecular-ion peak [FB+H ] at m/z
3+
3
42.1077 (Fig. S3). When the Fe ion was added into the
solution of FB, the peak at m/z 468.0734 is assignable to
Confocal fluorescence imaging in live cell
The cells were incubated with a 1μM FB in HEPES buffer for
3+
– +
[
FB+Fe +2Cl ] species (Fig. S5). This result confirmed that 1:1
3+
stoichiometry complex between FB and Fe . In the presence of
30 min at 37 ℃ in a CO
2
incubator (95% relative humidity, 5%
PPi, FT-MS spectra displayed a molecular-ion peak at m/z
CO ). After washed with HEPES for three times, cells were
2
3+
3
42.1083 again (Fig. S6), indicating that the decomplexation of
treated with 10 μM Fe for another 20min, followed by the
incubation with 30 μM PPi for 20 min. As expected, the cells
3+
Fe ion in the presence of PPi led to the liberation of
3+
fluorophore, FB.
untreated with Fe showed strong blue fluorescence (Fig. 11A)
O
O
3+
Fe3+
while the cells treated with Fe displayed no fluorescence by
C
C
N
OH
Fe3+
3+
N
OH
contrast (Fig. 11B). It is well known that the Fe could be taken
up into the live cells by diffusion through porins and transport by
N
N
N
H
N
H
OH
O
O
OH
O
O
PPi
47
transferrin and lactoferrin. Moreover, a remarkable fluorescen-
3
3 ++ PPi
ce enhancement was recorded when the cells were further treated
with PPi (Fig. 11C), indicating that PPi penetrate live cell
membrane through a sodium-dependent transporter and in which
FF ee
CH3
CH3
3+
3
+
it interacted with FB-Fe
leading to the recovery of
Scheme 2. The proposed mechanism for PPi detection by FB-Fe
ensemble.
fluorescence. The results suggested that probe FB is well suited
for in vivo imaging of Fe and its in situ generated FB-Fe can
3
+
3+
3+
The recognition mechanism of FB toward Fe and PPi)
(delete)
be employed for sensing of PPi in biological systems.
In order to better understand the nature of the coordination of
3+
Fe with FB, energy-optimized structures of FB and its
corresponding metal complexes were calculated by density
functional theory (DFT) calculations, using B3LYP hybrid
functional and split basis set with LANL2DZ for Fe and 6-31G*
3+
for other atoms for simple receptor FB and FB-Fe complex.
The spatial distributions and orbital energies of the highest
occupied molecular orbital (HOMO) and the lowest unoccupied
molecular orbital (LUMO) of FB and its corresponding metal
complexes were also calculated. As shown in Fig. 10, the HOMO
was distributed on the substituted imidazole ring in FB, whereas
LUMO was distributed on the coumarin ring in FB. Meanwhile,
Fig.11. Confocal bright-field (top), and fluorescence (bottom) imaging of
3
+
Fe and PPi in living Hep G2 cells. (A) Cells stained with FB (1 μM) at 37℃
3+
2
in a 5% CO incubator for 30 min, (B) and treated with Fe (10 μM) for 20
min, (C) then the cells incubated with PPi (30 μM) for another 20 min. Scale
bar = 40 μM.
3+
the π electrons of HOMO orbitals of FB-Fe were mainly
distributed on the coumarin ring. The LUMO was distributed on
Conclusion
3+
the imidazaole ring in FB-Fe . The energy gaps between the
3+
HOMO and LUMO in the FB and FB-Fe were calculated to be
.11 eV and 2.62 eV, respectively, indicating that the binding of
We have developed a new fluorescent chemosensor FB based
on coumarin, the specific binding of FB to Fe led to strong
fluorescence quenching through the 1:1 complex formation.
Furthermore, the in situ generated nonfluorescent FB-Fe
complex was employed for the specific recognition of PPi by
fluorescence turn-on signaling through a displacement process.
3+
3
3+
Fe to FB decreased the HOMO-LUMO energy gap of the
complex and stabilized the system. Thus, these results showed a
favorable complexation according to proposed coordination.
3+

Confocal microscopy imaging implied that FB can be potentially
used as a promising candidate for Fe and PPi imaging in Hep
G2 cell.
37. Takashima, I.; Kinoshita, M.; Kawagoe, R.; Nakagawa, S.;
3+
Sugimoto,M.; Hamachi, I., Ojida, A. Chem. Eur. J. 2014, 20,
2
184-2192.
3
3
4
8.
Meng, Q.T.; Wang, Y.; Yang, M.; Zhang, R.; Wang, R. J.;
Zhang,Z.Q. RSC Adv. 2015, 5, 53189-53197.
Acknowledgements
9. Bender, D. R.; Kanne, D.; Frazier, J. D.; Rapoport, H. J.
Org.Chem.1983, 8, 2709-2719.
0. Synthesis and Characterization the fluorescence probe FB
This work was supported by National Natural Science
Foundation of China (21506106) and the Key Laboratory Project
of Liaoning Province (2008S127)
L-Histidine (0.512g,
3
mmol), 7-hydroxy-4-methyl-2-oxo-2H-
chromene-8-carbaldehyde (2) (0.673 g, 3.3 mmol) and 20 mL acetic
acid as solvent were added to a round flask and the mixture was stirred
and refluxed for 12 h to yield a yellow precipitate. After cooling to
room temperature, the precipitate was filtered, washed with methanol
and dried under vacuum to obtain FB in 68% yield without other
purification. m. p. 202.5-203.7ºC; FT-IR (KBr): 3435, 3094, 1709,
References and notes
1
.
Zhang, W. S.; Tang, B.; Liu, X.; Liu, Y. Y.; Xu, K. H.; Ma, J. P.; Tong,
L. L.; Yang. G. W. Analyst. 2009, 134, 367-371.
-
1
1649, 1627, 1583, 1506, 1486, 1411, 1348, 1308, 1186, 851, 742cm ;
1
2
.
.
.
.
.
.
.
.
Zhou, J. W.; Outlaw, V. K.; Townsend, C. A.; Bragg, A. E. Chem. Eur.
J. 2016, 22, 15212-15215.
Tateno, K.; Ogawa, R.; Sakamoto, R.; Tsuchiya, M.; Otani, T.; Saito, T.
Org. Lett. 2014, 16, 3212-3215
H NMR (500 MHz, DMSO) δ: 8.64 (s,1H, CH=N), 7.67 (s, 1H, Ar ),
7.62(d, J=10Hz, 1H, Ar ), 6.87(s, 1H, Ar ), 6.58 (d, J=10Hz, 1H, Ar ),
3
4
5
6
7
8
9
1
6.04 (s, 1H, Ar), 4.73 (t, J=5Hz, 1H, CH), 3.25 (q, 1H, H-CH ), 3.10(q,
2
1
3
1H, H-CH ), 2.34(s, 3H, CH ); C NMR δ: 175.85, 170.47, 159.34,
2
3
Outlaw, V. K.; Zhou, J. W.; Bragg, A. E.; Townsend, C. A. RSC. Adv.
154.58, 130.49, 125.89, 117.78, 117.21, 116.59, 106.34, 103.56,
101.63, 61.43, 31.31, 17.40; MS, m/z: 342.1083; Element analysis (%)
calcd. for C H N O : C, 59.82; H, 4.43; N, 12.31. Found: C, 59.95;
2
016, 6, 61249-61253.
Wang, Y. F.; Zhang, L.; Zhang, G. J.; Wu, Y.; Wu, S. Y.; Yu, J. J.;
Wang, L.M. Tetrahedron Lett. 2014, 55, 3218-3222.
Li, Z.X.; Zhou, W.; Zhang, L.F.; Yuan, R.L.; Liu, X.J.; Wei, L.H.; Yu,
M.M. J. Lumin. 2013, 136, 14-144.
Kim, H.; Kim, K.B.; Song, E.J.; Hwang, I.H.; Noh, J.Y.; Kim, P.G.;
Jeong, K.D.; Kim, C. Inorg. Chem. Commun. 2013, 6, 72-76.
Chen, C. H.; Hung, P. J.; Wan, C. F.; Wu, A. T. Inorg. Chem. Commun.
1
7
15
3
5
H, 4.40; N, 12.27.
41.
42.
Wei, T. B.; Zhang, P.; Shi, B.B.; Chen, P.; Lin, Q.; Liu, J.;
Zhang, Y. M. Dyes. Pigm. 2013, 97, 297-302.
Job, P. Ann. Chim. 1928, 9, 113-203.
43. Benesi, H.A.; Hildebrand, J. H. J. Am. Chem. Soc. 1949, 71,
27032707.
44. Mocak, J.; Bond, A. M.; Mitchell, S.; Scollary, G. Pure. Appl.
Chem. 1997, 69, 297-302.
2
013, 38, 74-77.
Huang, L.; Hou, F.; Cheng, J.; Xi, P.; Chen, F.; Bai, D.; Zeng, Z.; Org.
Biomol. Chem. 2012, 10, 9634-9638.
45.
Kumar, M., Kumar, R.; Bhalla, V.; Sharma, P.R.; Kaur,
0. D’Autreáux, B.; Tucker, N.P.; Dixon, R.; Spiro, S. Nature. 2005,
37,769-772.
T.;Qurishi,Y. Dalton. Trans. 2012, 41, 408-412.
4
46. Thomsen, V.; Schatzlein, D.; Mercuro, D. Spectroscopy, 2003
18,112-118.
,
1
1
1. Lee, J.; Helmann, J. D. Nature. 2006, 440, 363-367.
2. Wang, J.; Zhang, D.; Liu, Y.; Ding, P.; Wang, C.; Ye, Y.; Zhao, Y.
Sens. Actuators B. 2014, 191, 344-350.
47.
Mackenzie, E. L.; Iwasaki, K.; Tsuji, Y. Anti. Redox.
Signal.2008,10, 997-1014.
1
3. Xie, P.; Guo, F.; Xia, R.; Wang, Y.; Yao, D.; Yang, G.; Xie, L. J.
Lumin. 2014, 145, 849-854.
1
1
4. Har, M. C.; Tanu, G. Tetrahedron Lett., 2015, 56, 793-796.
5. Qin, J. C.; Yang, Z.Y.; Wang, G. Q.; Li, C.R.Tetrahedron Lett.,2015, 56,
5
024-5029.
6. Yi, C.; Tian, W. W.; Song, B.; Zheng, Y. P.; Qi, Z. J.; Qi, Q. J. Lumin.,
013, 141, 15-22.
7. Garcia, V.; Fernandez-Lodeiro, A.; Lamelas, R.; Macias, A.; Bastida, R.;
Bertolo, E.; Nunez, C. Dyes Pigm. 2014, 110, 143-151.
8. Kim, H. J.; Lee, J. H.; Hong, J. I. Tetrahedron Lett. 2011, 52, 4944-
946.
1
1
2
1
4
1
9. Bowler, M. W.; Cliff, M. J.; Waltho, J. P.; Blackburn, G. M.
New J. Chem. 2010, 34, 784-794.
2
2
0. Hirsch, A. K.; Fischer, F. R.; Diederich, F. Angew. Chem. Int. Ed.
2
007, 46, 338-352.
1. Kim, S. K.; Lee, D. H.; Hong, J. I.; Yoon, J. Acc. Chem. Res. 2009, 42,
3-31.
2
2
2
2
2. Nyren, P. Anal. Biochem. 1987, 167, 235-238.
3. Kim, S.Y.; Hong, J. I.; Tetrahedron Lett. 2009, 50, 1951-1953.
4. Timms, A. E.; Zhang, Y.; Russell, R. G. G.; Brown, M. A.Rheumatology.
2
002, 41, 725-729.
2
5. Hessle, L. K.; Johnson, A.; Anderson, H. C.; Narisawa, S.; Sali, A.;
Goding, J. W.; Terkeltaub, R.; Millan, J. L. Proc. Natl. Acad. Sci. 2002,
9
9, 9445-9449.
2
2
6. Beck, C.; Morbach, H.; Stenzel, M.; Collmann, H.; Schneider, P.;
Girschick, H. J. Open Bone J. 2009, 1, 8-15.
7. Li, C.; Wang, L.; Deng, L.; Yu, H.; Huo, J.; Ma, L.; Wang, J. J. J. Phys.
Chem. B. 2009, 113, 15141-15144.
2
8. Khatua, S.; Choi, S. H.; Lee, J.; Kim, K.; Do, Y.; Churchill, D. G. Inorg.
Chem. 2009, 48, 2993-2999.
2
3
3
3
3
3
9. Xu, Z.; Singh, N. J.; Lim, J.; Pan, J.; Kim, H. N.; Park, S.; Kim, K. S.;
Yoon, J. J. Am. Chem. Soc. 2009, 131, 15528-15533.
0. Satoh, T.; Shinoda, Y.; Alexandrov, M.; Kuroda, A.; Murakami, Y.
Anal. Biochem. 2008, 379, 116-120.
1. Wang,Y.; He, X.; Wang, K.; Ni, X. Biosens. Bioelectron. 2010, 25,
2
101-2106.
2. Feng, J.; Chen, Y.; Pu, J.; Yang, X. L; Zhang, C.; Zhu, S.; Zhao, Y. S.;
Yuan, Y. H.; Yuan, H. D.; Liao, F. Anal. Biochem. 2011, 409, 144-149.
3. Shao, N.; Wang, H.; Gao, X.; Yang, R.; Chan, W. Anal. Chem. 2010,
8
2, 4628-4636.
4. (a) Su, X.; Zhang, C.; Xiao, X.; Xu, A.; Xu, Z.; Zhao, M. Chem.
Commun. 2013, 49, 798-800. (b) Liu, Y.; Schanze, K. S. Anal. Chem.
2
008, 80, 8605-8612.
3
5. Karak, D.; Das, S.; Lohar, S.; Banerjee, A.; Sahana,
A.;Hauli,I.;Mukhopadhyay, S. K.; Safin, D. A.; Babashkina, M. G.;
Bolte, M.; Garcia, Y.; Das, D. Dalton Trans. 2013, 42, 6708-6715.
6. Hou, J.T.; Li, K.; Yu, K. K.; Wu, M. Y.; Yu, X.
Q.Org.Biomol.Chem. 2013, 11, 717-720.
3

6
Highlights
1. Chemosensor FB displayed highly
sensitivity fluorescence “ON-OFF-ON”
3+
response to Fe and PPi.
3+
2
. The detection limits of FB for Fe and
3+
FB-Fe for PPi were estimated to be
-8
-8
8
.73×10 M and 1.25×10 M.
3
4
. This chemosensor FB was applied to
living cells imaging.
. A B3LYP/6-31G(d,p) basis set was
employed for optimization of FB and
3+
FB-Fe complex.

O
O
Fe3+
C
C
N
OH
N
OH
Fe3+
N
N
N
H
N
H
OH
PPi
O
O
OH
O
O
3
3 ++ PPi
FF ee
CH3
CH3