A fluoran-based fluorescent probe via a strategy of blocking the intramolecular photoinduced electron transfer (PET) process

Article abstract of DOI:10.1016/j.tetlet.2017.04.037

A novel fluoran-based fluorescent probe 2 has been designed and synthesized by using a strategy of blocking the intramolecular photoinduced electron transfer (PET) process. The probe keeps a ring-closed spirolactone structure in aqueous buffer solution. However, the oxidation of the probe by ClO^? perturbs a new equilibrium of the structural interconversion between the nonfluorescent spirolactone and the fluorescent ring-opened zwitterion, which generates a highly selective fluorescent probe for ClO^?. Meanwhile, the probe is cell membrane permeable and can be utilized as fluorescent probe for imaging ClO^? in living cells.

Full text of DOI:10.1016/j.tetlet.2017.04.037

Accepted Manuscript
A fluoran-based fluorescent probe via a strategy of blocking the intramolecular
photoinduced electron transfer (PET) process
Kun Huang, Song He, Xianshun Zeng
PII:
S0040-4039(17)30467-7
DOI:
http://dx.doi.org/10.1016/j.tetlet.2017.04.037
TETL 48829
Reference:
Tetrahedron Letters
To appear in:
Received Date:
Revised Date:
Accepted Date:
1 March 2017
5 April 2017
8 April 2017
Please cite this article as: Huang, K., He, S., Zeng, X., A fluoran-based fluorescent probe via a strategy of blocking
the intramolecular photoinduced electron transfer (PET) process, Tetrahedron Letters (2017), doi: http://dx.doi.org/
10.1016/j.tetlet.2017.04.037
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Tetrahedron Letters
jour nal homepage: w ww.elsevier. com
A fluoran-based fluorescent probe via a strategy of blocking the intramolecular
photoinduced electron transfer (PET) process
Kun Huang a, Song He b, Xianshun Zeng a, b, ∗
a School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
b Tianjin Key Laboratory for Photoelectric Materials and Devices, School of Materials Science & Engineering, Tianjin University of Technology, Tianjin
300384, China. Email: xshzeng@tjut.edu.cn.
ARTICLE INFO
ABSTRACT
A novel fluoran-based fluorescent probe 2 has been designed and synthesized by using a strategy
of blocking the intramolecular photoinduced electron transfer (PET) process. The probe keeps a
ring-closed spirolactone structure in aqueous buffer solution. However, the oxidation of the
probe by ClO- perturbs a new equilibrium of the structural interconversion between the
nonfluorescent spirolactone and the fluorescent ring-opened zwitterion, which generates a highly
selective fluorescent probe for ClO-. Meanwhile, the probe is cell membrane permeable and can
be utilized as fluorescent probe for imaging ClO- in living cells.
Article history:
Received
Received in revised form
Accepted
Available online
Keywords:
Fluoran
2009 Elsevier Ltd. All rights reserved.
Fluorescent probe
Hypochlorite
PET
Reactive oxygen species (ROS) has attracted much attention in
fluorescent probes for imaging in recent years because they
mediate a variety of physiological and pathological processes.1-3
Among ROS, HClO is a weak acid (pKa = 7.6) and can partially
dissociate to hypochlorite under physiological conditions, which
is widely used in daily life as disinfectant, antimicrobial or
bleaching agent with the concentration in the range of 10-5 - 10-2
M.4 On the other hand, hypochlorous acid/hypochlorite
(HClO/ClO-) play important role in inflammation and the
immune defense against microorganisms.5 The endogenous ClO-
is biologically produced from peroxidation of Cl- ions catalyzed
by the enzyme myeloperoxidase (MPO) mainly in leukocytes,6
including neutrophils, macrophages and monocytes.7 However,
process of oxidation. It is well known that fluoran dyes, another
type of dyes containing xanthene chromophore,14 were widely
used as thermosensitive dyes in print industry by taking full
advantage of the thermo-controlled ring-opening process of the
spirolactone (Scheme 1).15 However, only a small amount of
fluoran-based chromogenic chemosensors were developed for
sensing of ions.16-18 To the best of our knowledge, no fluoran-
based fluorescent probe has been reported up to date.
maintaining
a
reasonable ClO- concentration within the
physiological environments is crucial for numerous cellular
functions. Excessive or uncontrolled production of ClO- can
cause tissue damage and diseases, including arthritis,8 cancers,9
and neurodegeneration.10 Therefore, simple, sensitive and reliable
method for detection of ClO- is urgently needed.
Fluorescent probes have been widely developed for ClO-
detection in the past decade due to their high sensitivity, high
selectivity and real-time detection.11,12 In recent years, a great
variety of fluorophores were employed in the design of
chemosensors for ClO-, such as rhodamine, fluorescein, 1,8-
naphthalimide, cyanine, coumarin, phenothiazine, etc.13 Among
them, a general strategy for the design of fluorescent probes for
ClO- is to connect an organic fluorophore with an easily oxidized
moiety by taking advantage of the strong oxidation property of
ClO-, which produce optical signal changes corresponding to the
Scheme 1 Structures of rhodamine and fluoran dyes.
During the investigation of the optical properties of the known
fluoran dye 119 (Scheme 2), we found that the dye exhibited a
stable ring-opened zwitterionic structure as shown in Fig 1a in
water phase from pH 5 to 10, and with its characteristic π-π*
transitions absorption band at ca. 550 nm. While the pH value is
lower than 4, the maximum absorption band of 1 was blue shifted
to ca. 455 nm due to the protonation of the amino group (Fig.
S1a). However, the fluoran dye
1 only showed strong
fluorescence with the pH value lower than 4 (Fig. S1b). The
results can be rationalized that even though the fluoran dye 1
keeps a ring-opended zwitterionic structure from pH 5 to 10, its
fluorescence signal is quenched by the free amino group via a
∗ Corresponding author. Tel.: +86-022-6021-6748; fax: +86-022-6021-6748; e-mail: xshzeng@tjut.edu.cn

2
Tetrahedron Lett
PET mechanism from the electron-donating N atom to the
excited state of the fluorophore, resulting in the fluorescence
signal quenching (Fig. 1b).
characterized by high-resolution mass spectrometry (HRMS), 1H-
and 13C-NMR spectra analyses (see supporting information).
Fig. 2 Fluorescence emission changes of probe 2 (5 µM) upon addition
of various ROS (30 µM) in PBS buffer (10 mM, EtOH /H2O = 1/4, pH
7.4). Inset: fluorescence intensity changes at 580 nm. 1-12: probe, ClO-,
·
-·
1
-
H2O2, TBHP, OH, ONOO-, O2 , NO, O2, NO2 , NO3- and AS; λex: 500
Fig. 1 a) Proposed fluorescence emission mechanism of fluoran 1. b) the
PET mechanism of 1.
nm, Slit: 10 nm, 10 nm.
Inspired by the aforementioned optical properties of the
fluoran dye 1, we hypothesized that the introduction of electron-
deficient functional group on the amino group may decrease its
energy level of the highest occupied molecular orbital (HOMO),
and prevents its electron transfer to the excited state of the
fluorophore, resulting the fluorescence recovery of the
fluorophore. Based on this hypothesis, we reported herein a novel
fluoran-based ClO¯-selective fluorescent probe 2 by introducing
an electron-deficient diphenylphosphinobenzoyl group on the
amino group to decrease its HOMO level. It is also important to
note that a few of P(III) atom containing probes have been
reported for H2O2 or other ROS detections by using the
P(III)/P(V)-involved PET on/off control.20 Probe 2 exhibits a
high sensitivity and high selectivity for ClO- detection.
Meanwhile, the probe is cell-permeable and can be used for
imaging ClO- in the living cell.
Fig. 3 Fluorescence intensity changes [(Fi-FProbe)/(FClO--Fprobe)] of probe 2
(5 µM) at 580 nm towards ClO- (6 equiv.) in the presence of other ROS(6
equiv.) in PBS buffer (0.01 M, EtOH/H2O = 1/4, pH 7.4). 1 - 11: ClO-,
·
-·
1
-
H2O2, TBHP, OH, ONOO-, O2 , NO, O2, NO2 , NO3- and AS; λex: 500
nm, Slit: 10 nm, 10 nm.
Firstly, the absorption and fluorescence responses of the probe
2 in the absence and the presence of various ROS were
performed in PBS buffer (10 mM, EtOH/H2O = 4/1, pH 7.4). As
shown in Fig. S2, probe 2 (5 µM) exhibited weak absorption
band over 400 nm, indicated that the probe keeps a ring-closed
spirolactone structure in aqueous buffered solution. Nevertheless,
the addition of ClO- induced two significant absorption peaks at
ca. 500 nm (ε = 1.72 × 104 M-1 cm-1) and 535 nm (ε = 1.52 × 104
M-1 cm-1), respectively, accompanied by significant color change
from nearly colorless to faint red, which may correspond to the
ClO--elicited ring-opened form of the probe. In contrast, the
addition of other ROS contributed to no significant absorption or
color changes (Fig. S3). When excited at 500 nm, the probe (5
µM) exhibited weak fluorescence at around 580 nm under the
same conditions (Fig. 2). Among the ROS tested, the probe only
showed significant fluorescence enhancements at 580 nm with
ClO-, the addition of other ROS induced no obvious fluorescence
changes of the probe. It is noted that diphenylphosphinobenzoate
Scheme 2 Synthesis of the probe 2, reagents and conditions: i) 98%
H2SO4, 55 oC, 24 h; ii) ca. 36% H2SO4, 95 oC, 4 h; iii) DIEA, HATU, dry
CH2Cl2, 12h, Ar.
The synthetic route for probe 2 was shown in Scheme 2. To
synthesize the probe 2, compound 1 was prepared according to
the literature20 by condensation of 4-acetylamino-phenol with 2-
(4-(N,N-diethylamino)-2-hydroxyben-zoyl)benzoic acid via
a
moiety was commonly used as
a candidate for HNO
conveniently acid-promoted Friedel-Crafts acylation protocol in
concentrated H2SO4, and subsequently was hydrolyzed in dilute
H2SO4 to remove the acetyl group. Finally, probe 2 was obtained
in 35% yield through the reaction of compound 1 with 2-
(diphenylphosphino)benzoic acid in the presence of condensation
agent 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluroni-
um hexafluorophosphate (HATU) in anhydrous dichloromethane
(Scheme 2) under Ar atmosphere. The structure of 2 was
recognition.21, 22 However, we found Angeli's salt (AS, as a HNO
processor) elicited no obvious fluorescence changes compared
with the fluorescence spectra of the probe alone. Subsequently,
the competition experiments were carried out to evaluate
fluorescence changes of the probe towards ClO- in presence of
other ROS. As can be seen from Fig. 3, the fluorescence response
of the probe towards ClO- is not influenced by the presence of

other ROS. The results clearly suggested the probe can respond
to ClO- with high selectivity among various ROS.
scheme 3, the probe in aqueous buffered solution exhibits mainly
in the form of spirolactone 2 and a very minor portion of ring-
opened zwitterionic structure 2', which correspond to a very
weak absorption at ca. 500 nm and a weak fluorescence emission
at 580 nm. Along with the oxidation of P atom by ClO-, the probe
2 was converted to spirolactone 3. However, the oxidation of 2
perturbs a new equilibrium of the structural interconversion
between the spirolactone 3 and the ring-opened zwitterion 3'. The
absorption and fluorescence spectra indicated that the oxidized
product 3 exhibits mainly in the form of ring-opened zwitterion
3' (Fig. 4 and Fig. 5). On the other hand, the electron-rich P atom
within the probe 2 can partially quench the fluorescence of the
ring-opened zwitterionic structure 2' via PET process (Scheme 3),
which was further proved by absorption and fluorescence spectra
(Fig. S8). Upon the addition of trifluoric acetic acid (TFA), the
absorption and fluorescene intensities of 2 are obviously
increased. However, the addition of ClO- to the acidic solution of
2 induced no more increase of the absorption intensity (Fig. S8a),
nevertheless, along with the oxidation of the P atom by ClO- it
elicited an obvious fluorescence enhancement which suggested
the block of the PET process from the electron-donating P atom
to the excited state of the xanthene fluorophore (Fig. S8b). To get
more solid evidence that the recognition process is the oxidation
of P atoms by ClO-, the reaction mixture of the probe 2 with ClO-
was further investigated by the high resolution mass spectra
(HRMS). As shown in Fig. S9, the most abundant peak at m/z [M
+ H]+ = 691.2389 and a weak peak at m/z [M + Na]+ = 713.2207
corresponding to [3' + H]+ [calc. m/z 691.2362] and [3' + Na]+
[calc. m/z 713.2181], respectively, demonstrated the oxidation of
P atom by ClO-. To further elucidate the structure of product 3
and/or 3', the reaction between 2 and ClO- was investigated.
After purified by column chromatography. It was obtained as
Fig. 4 Absorption titration spectra of probe 2 (5 µM) in PBS buffer (0.01
M, EtOH/H2O = 1/4, pH 7.4) upon addition of ClO- (0 - 36.6 µM). Inset:
the plot of absorbance intensity as a function of the concentration ratio of
CClO-/CProbe
.
yellowish-brown solid in 41% yield. It showed a typical P(V) 31
P
NMR spectrum at 35.452 ppm (Fig. S10). Compared with 2 (δ =
-10.268 ppm), it is largely downfield-shifted (over 45 ppm). Due
to the structure conversion between 3 and 3', its 1H and 13C NMR
are difficult to assignments (Fig. S11 - S12).
Fig. 5 Fluorescence titration spectra of probe 2 (5 µM) in PBS buffer
(0.01 M, EtOH/H2O = 1/4, pH 7.4) upon addition of ClO- (0 - 36.6 µM).
Inset: the plot of fluorescence intensity as a function of the concentration
ratio of CClO-/Cprobe. λex: 500 nm, Slit: 10 nm, 10 nm.
To apply the probe in more complicated systems, pH-
dependence experiments were investigated in the presence and
absence of ClO- by absorption and fluorescence spectra. The
absorption changes of probe and probe/ClO- systems under
different pH values were illustrated in Fig. S5. From pH 4 to pH
10, no significant absorption changes were observed for the
probe. In contrast, in the presence of ClO-, the probe exhibited an
obvious absorption enhancement at 500 nm from pH 4 to 10.
The absorption intensity reached a maximum at pH 4.0 and had a
gradual decrease in pH range 4 - 7, and then no obvious changes
can be observed from pH 7 to 10. The pH profile evaluated by
fluorescence spectra also exhibited the same tendencies as
determined by absorption spectra (Fig. S6). The results indicated
that 2 can be utilized as ClO--selective probe over a broad pH
range (pH 4 - 10). Finally, the time-dependent fluorescence
responses of 2 under excitation at 500 nm were evaluated in the
absence and presence of ClO-. As shown in Fig. S7, a weak
fluorescence signal was observed with the free probe in PBS
buffer (10 mM, EtOH/H2O = 1/4, pH 7.4). However, the
fluorescence intensity increased immediately at the first 120
seconds and reached its maximum within 5 min after the addition
of ClO- (6.0 equiv.), indicated that the reaction event between the
probe 2 and ClO- could complete in less than 5 min. Based on the
aforementioned absorption and fluorescence changes before and
after the addition of ClO-, we suggested the spectra changes of
the probe 2 are relevant to the oxidation of P atom by ClO- and
subsequent ring-opened cascade reaction processes. As shown in
Shcheme 3 Proposed structural interconversions of the probe 2 before
and after the addition of ClO-, and their fluorescence properties.
To further evaluate practical applicability of 2, it was
employed in fluorescence microscopy images of living L929
cells. The cultured L929 cells were incubated with the probe 2 (3
o
µM) in culture medium at 37 C for 1 h, and then washed with
PBS buffer to remove excess probes. As shown in Fig. 6, laser
scanning confocal microscopy image showed that the L929 cells
treated with the probe for 1 h gave very weak intracellular
fluorescence signals (Fig. 6b). Upon treatment with 3 equivalents
of ClO- under the same conditions, the cells pretreated with the
probe exhibited significant fluorescence enhancement in intensity
(Fig. 6d). These results demonstrated the probe is cell membrane
permeable and can be used for imaging ClO- in living cells.

4
Tetrahedron Lett
12. (a) Zhang, Y. R.; Liu, Y.; Feng, X.; Zhao, B. X. Sens. Actuators B. 2017,
240, 18-36. (b) Wei, F.; Lu, Y.; He, S.; Zhao, L.; Zeng, X. Anal. Methods
2012, 4, 616-618.
13. (a) Liang, L.; Liu, C.; Jiao, X.; Zhao, L.; Zeng, X. Chem. Commun. 2016,
52, 7982-7985. (b) Ren, M.; Deng, B.; Zhou, K.; Kong, X.; Wang, J. Y.;
Xu, G.; Lin, W. J. Mater. Chem. B. 2016, 4, 4739-4745. (c) Zhang, R.;
Zhao, J.; Han, G.; Liu, Z.; Liu, C.; Zhang, C.; Liu, B.; Jiang, C.; Liu, R.;
Zhao, T.; Han, M. Y.; Zhang, Z. J. Am. Chem. Soc. 2016, 138, 3769-
3778. (d) Wu, Y.; Wang, J.; Zeng, F.; Huang, S.; Huang, J.; Xie, H.; Yu,
C.; Wu, S. ACS Appl. Mater. Interfaces. 2016, 8, 1511-1519. (e) Cheng,
T.; Zhao, J.; Wang, Z.; An, J.; Xu, Y.; Qian, X.; Liu, G. Dyes Pigm. 2016;
126: 218-223. (f) Zhang, W.; Liu, W.; Li, P.; Wang, J.; Wang, H.; Tang,
B. Chem. Commun. 2015, 51, 10150-10153. (g) Xu, Q.; Heo, C. H.; Kim,
G.; Lee, H. W.; Kim, H. M.; Yoon, J. Angew. Chem. 2015, 127, 4972-
4976. (h) Wang, B.; Chen, D.; Kambam, S.; Wang, F.; Wang, Y.; Zhang,
W.; Yin, J.; Chen, H.; Chen, X. Dyes Pigm. 2015, 120, 22-29. (i) Yuan,
L.; Wang, L.; Agrawalla, B.K.; Park, S. J.; Zhu, H.; Sivaraman, B.; Chang
,Y. T. J. Am. Chem. Soc. 2014, 137, 5930-5938. (j) Xiao, H.; Xin, K.;
Dou, H.; Yin, G.; Quan, Y.; Wang, R. Chem. Commun. 2015, 51, 1442-
1445. (k) Zhu, H.; Fan, J.; Wang, J.; Mu, H.; Peng, X. J. Am. Chem. Soc.
2014. 136, 12820-12823. (l) Zhang, Y. R.; Chen, X. P.; Zhang, J. Y.;
Yuan, Q.; Miao, J. Y.; Zhao, B. X. Chem. Commun. 2014, 50, 14241-
14244. (m) Liu, F.; Wu, T.; Cao, J.; Zhang, H.; Hu, M.; Sun, S.; Song, F.;
Fan, J.; Wang, J.; Peng, X. Analyst. 2013, 138, 775-778. (n) Wang, B.; Li,
P.; Yu, F.; Song, P.; Sun, X.; Yang, S.; Lou, Z.; Han, K. Chem. Commun.
2013, 49, 1014-1016. (o) Li, G.; Zhu, D.; Liu, Q.; Xue, L.; Jiang, H. Org.
Lett. 2013, 15, 2002-2005. (p) Liu, S. R.; Wu, S. P. Org. Lett. 2013, 15,
878-881. (q) Manjare, S. T., Kim, J., Lee, Y., Churchill, D. G. Org. Lett.
2013, 16, 520-523. (r) Wang, Q.; Liu, C.; Lu, Y.; He, S.; Liu, C.; Zhao,
L.; Zeng, X. Dyes and Pigments, 2013, 99, 733-739. (s) Moon, J. O.; Lee,
J. W.; Choi, M. G.; Ahn, S.; Chang, S. K. Tetrahedron Lett. 2012, 53,
6594-6597. (t) Cui, K.; Zhang, D.; Zhang, G.; Zhu, D. B. Tetrahedron
Lett. 2010, 51, 6052-6055.
Fig. 6 Confocal fluorescence images of living L929 cells. (a - b) Cells
was incubated with 2 (3 µM) for 1 h; (c - d) the cells loaded with 2 (3
µM) for 1 h; then treated with ClO- (9 µM) for 30 min. (a) and (c): bright
field image; (b) and (d): red channel at 574 - 638 nm. λex: 488 nm, Scar
bars: 20 µm.
In summary, the first fluoran-based fluorescent probe 2 has
been designed and synthesized by using a strategy of blocking
the intramolecular PET process. The probe keeps
a
nonfluorescent ring-closed spirolactone structure in aqueous
buffer solution. However, the oxidation of the P atom within
probe by ClO- induces a conversion from the nonfluorescent
spirolactone to the fluorescent ring-opened zwitterion, which
generates a high selective fluorescent probe for ClO-. Meanwhile,
the probe exhibits cell membrane permeability and can be used
for imaging ClO- in the living cell.
14. Gessner, T.; Mayer, U. Ullmann's encyclopedia of industrial chemistry,
Part A27, Triarylmethane and Diarylmethane Dyes. 2000, 460-463.
15. Muthyala R. (Ed.), Plenum Press, New York/London, 1997, pp.159–205.
16. Wang, S.; Gwon, S.Y.; Son, Y.A.; Matsumoto, S.; Hwang , I. J.; Kim, S.
H. Mol. Cryst. Liq. Cryst. 2009, 504,155-163.
17. Wang, S.; Gwon, S. Y.; Kim, S. H. Spectrochim. Acta. Part A 2010, 76,
293-296.
Acknowledgments
18. Wang, S.; Hwang, I. J.; Gwon, S. Y.; Kim, S. H. Fiber. Polym. 2010, 11,
1198-1200.
19. Burkinshaw, S. M.; Griffiths, J.; Towns, A. D. J. Mater. Chem. 1998, 8,
2677-2683.
We gratefully acknowledge the Natural Science Foundation of
China (NNSFC 21272172), and the Natural Science Foundation
of Tianjin (12JCZDJC21000).
20. (a) Shritz, R.; Shapira, R.; Borzin, E.; Tumanskii, B.; Reichstein, W.;
Meichner, C.; Schwaige, F.; Reichstein, P. M.; Kreyenschmid, J.; Dietrich
Haarer, D.; Kador, L.; Kador, L.; Eichen, Y. Chem. Eur. J. 2015, 21,
11531-11537. (b) Lan, M.; Di, Y.; Zhu, X.; Ng, T. W.; Xia, J.; Liu, W.;
Meng, X.; Wang, P.; Lee, C. S.; Zhang, W. Chem. Commun. 2015, 51,
15574-15577. (c) Soh, N.; Sakawaki, O.; Makihara, K.; Odo, Y.;
Fukaminato, T.; Kawai, T.; Irie, M.; Imato, T. Bioorg. Med. Chem. 2005,
13, 1131-1139. (d) Onoda, M.; Uchiyama, S.; Endo, A.; Tokuyama, H.;
Santa, T.; Imai, K. Org. Lett. 2003, 5, 1459-1461. (e) Lemieux, G. A.; de
Graffenried, C. L.; Bertozzi, C. R. J. Am. Chem. Soc. 2003, 125, 4708-
4709. (f) Okimoto, Y.; Watanabe, A.; Niki, E., Yamashita, T.; Noguchi, N.
FEBS lett. 2000, 474, 137-140.
References and notes
1. Lambeth, J. D. Free Radical Biol. Med. 2007, 43, 332-347.
2. McCord, J. M. Science 1974, 185, 529-531.
3. Chen, X.; Wang, F.; Hyun, J. Y.; Wei, T.; Qiang, J.; Ren, X.; Shin I.;
Yoon, J. Chem. Soc. Rev. 2016, 45, 2976-3016.
4. Aokl, T.; Munemorl, M. Anal. Chem. 1983. 55. 209-212.
5. Winterbourn, C. C.; Hampton, M. B.; Livesey, J. H.; Kettle, A. J. J. Biol.
Chem. 2006, 281, 39860-39869.
21. Kawai, K., Ieda, N., Aizawa, K., Suzuki, T., Miyata, N., Nakagawa, H. J.
Am. Chem. Soc. 2013, 135, 12690-12696.
22. Jing, X.; Yu, F.; Chen, L. Chem. Commun. 2014, 50, 14253-14256.
6. Fiedler, T. J.; Davey, C.A.; Fenna, R. E. J. Biol. Chem. 2000, 275, 11964-
11971.
7. Yap, Y. W.; Whiteman, M.; Cheung, N. S. Cell. Signalling. 2007, 19, 219-
228.
8. Steinbeck, M. J.; Nesti, L. J.; Sharkey, P. F.; Parvizi, J. J. Orth. Res. 2007,
25, 1128-1135.
Supplementary Material
9. Pattison, D. I.; Davies, M. J. Biochem. 2006, 45, 8152-8162.
10. Pattison, D. I.; Davies, M. J. Chem. Res. Toxicol. 2001, 14, 1453-1464.
11. (a) Yue,Y.; Huo, F.; Yin, C.; Escobedo, J. O.; Strongin, R. M. Analyst.
2016, 141, 1859-1873. (b) Jiao, X.; Liu, C.; Wang, Q.; Huang, K.; He, S.;
Zhao, L.; Zeng, X. Anal. Chim. Acta, 2017, doi.org/10.1016/j.aca.
2017.03.020
Supplementary data associated with this article can be found in the
online version, at http://dx.doi.org.
Click here to remove instruction text...

6
Tetrahedron Lett
Highlights
>A fluoran-based fluorescent probe has been
prepared.
>The probe exhibits high selectivity and sensitivity
towards ClO-.
>The probe can be used for imaging of ClO- in
living cells.