Colorimetric and ratiometric fluorescent chemosensor for fluoride ion based on perylene diimide derivatives

Article abstract of DOI:10.1016/j.dyepig.2012.01.024

Based on a perylene diimide derivatives(PDIs) platform, AM-PDIs was rationally designed and synthesized as a new colorimetric and ratiometric fluorescent sensor for naked-eye detection of fluoride ion with high selectivity over other halide ions. Addition

Full text of DOI:10.1016/j.dyepig.2012.01.024

Dyes and Pigments 94 (2012) 410e415
Contents lists available at SciVerse ScienceDirect
Dyes and Pigments
journal homepage: www.elsevier.com/locate/dyepig
Colorimetric and ratiometric fluorescent chemosensor for fluoride ion based
on perylene diimide derivatives
*
Zhi Jun Chen, Li Min Wang , Gang Zou, Liang Zhang, Guan Jun Zhang, Xiao Fei Cai, Ming Shuang Teng
Shanghai Key Laboratory of Functional Materials Chemistry and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road,
Shanghai 200237, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Based on a perylene diimide derivatives(PDIs) platform, AM-PDIs was rationally designed and synthe-
sized as a new colorimetric and ratiometric fluorescent sensor for naked-eye detection of fluoride ion
with high selectivity over other halide ions. Addition of fluoride ion to a dichloromethane(DCM) solution
of AM-PDIs resulted in an obvious color change (from red to blackish green) because of a large red shift
(151 nm) in absorption. The recognition mechanism was attributed to the intermolecular proton transfer
between a hydrogen atom on the amide N position of sensor and the fluoride anion. The detection limit
Received 23 December 2011
Received in revised form
26 January 2012
Accepted 30 January 2012
Available online 8 February 2012
was calculated to be 0.14 mM.
Keywords:
Ó 2012 Elsevier Ltd. All rights reserved.
PDIs
Naked-eye detection
Fluoride
Ratiometric
Chemosensor
Intermolecular proton transfer
1. Introduction
absorption or the emission at two wavelengths. Thus, ratiometric
fluorescent sensors can provide a built-in correction for environ-
mental effects [20].
The design and construction of sensory molecules for recogni-
tion and sensing of anions has received considerable attention in
recent years [1e6], as anions play a fundamental role in a wide
range of chemical, biological, medical, and environmental
processes [7e9]. Among the anions, fluoride, the smallest anion
with a high charge density, is an attractive target for sensor design
due to its association with nerve gases, the analysis of drinking
water, and the refinement of uranium used in nuclear weapons
manufacture [10e12]. Fluoride is a strong hydrogen bond acceptor
and has a high affinity to silicon and boron. These unique chemical
properties have been widely deployed in the design and develop-
ment of many fluorescent sensors for fluoride anions [13e19].
However, many of them are based on fluorescence measurement at
a single wavelength, which may be influenced by variations in the
sample environment. To increase the selectivity and sensitivity,
ratiometric fluorescent sensors are used, which involves the
observation of changes in the ratio of the intensities of the
Perylene dianhydride (PTCDA) and its derivatives Perylene
diimide derivatives (PDIs) represent a class of strongly fluorescent
high performance pigments that have excellent chemical, thermal,
photo, and weather stability [21]. Recently, significant progress
has been made to use PDIs-containing materials in organic field-
effect transistors (OFETs), fluorescent solar, collectors, electro-
photographic devices, dye lasers, organic photovoltaic cells (OPVs),
and optical power Limiters [22e24]. Also, PDIs show good optical
and electrical properties due to their high photoluminescence
efficiency and good chemical and thermal stability [25,26], Which
indicates they could be good platforms for the fluorescent sensors.
Therefore, many work about fluorescent sensors based on the PDIs
has been reported. But most of these fluorescent sensors reported
before were for cations and biomolecules [27e34], few of these
sensors were for anions. To the best of our knowledge, there were
no reports on the colormetric and ratiomeitric fluorescent sensors
based on PDIs for fluoride ion. Herein, we designed and synthe-
sized a new colorimetric and ratiometric fluorescent sensor for
naked-eye detection of fluoride ion. The sensor exhibited a large
red shift (151 nm) in absorption and it also exhibited a high
selectivity for fluoride ion over other anions in DCM. The detection
* Corresponding author. Tel./fax: þ86 21 64253881.
E-mail address: wanglimin@ecust.edu.cn (L.M. Wang).
0143-7208/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.dyepig.2012.01.024

Z.J. Chen et al. / Dyes and Pigments 94 (2012) 410e415
411
limit was calculated to be 0.14 uM due to our rational design. The
synthesis of AM-PDIs started from PTCDA 1, via Imidization,
nitration, reduction and acetylation steps, AM-PDIs was obtained,
as shown in Scheme 1.
2. Materials and methods
2.1. Experimental
2.1.1. General
Reagents and solvents were reagent grade, used as received
unless otherwise noted. All solvents used in wateresensitive
reactions were freshly distilled: THF from K/benzophenone,
CH2Cl2 from CaH2. Reactions were monitored by TLC. Flash
chromatography separations were carried out using silica gel
(200e300 mesh). Yields are of purified product and were not
optimized. 1HNMR were recorded at 400 MHz. Infrared spectra
was measured on the Fourier Transform Infrared (FT-IR) Spec-
troscopy (Nicollet, Thermo Scientific, USA). Absorption spectra
was carried out on a Thermo UVeVis spectrophotometer and
Fluorescence spectra was measured on a Thermo Fluorescence
spectrophotometer.
2.2. Synthesis
2.2.1. Synthesis of N,N0-dicyclohexyl-perylene-3,4,9,10-
tetracarboxylic acid bisimide 2
PTCDA 1 (5 g, 9 mmol) was placed in a 250-mL round-bottomed
flask, and cyclohexane (86 g, 870 mmol) was added with stirring.
The mixture was heated to reflux for 15 h. The precipitate was
filtered, washed with 5% (w/w) NaOH (100 mL) and ethanol
(50 mL), Then dried to give 4.5 g of compound 2 (93%) as a red solid.
compound 2: 1HNMR (CDC l3): 8.01 (d, J ¼ 10.8 Hz, 4H), 7.83 (d,
Fig. 1. (a): UVevis absorption spectra of AM-PTCDI (1 ꢁ10ꢂ5 M) in DCM upon addition
of 0e12 equiv of TBAF. b: Emission spectra of AM-PTCDI (1 ꢁ 10ꢂ5 M) in DCM upon the
addition of 0e12 equiv of TBAF.
J ¼ 10.8 Hz, 4H), 5.01 (m, 2H), 2.53 (m, 4H), 1.92 (m, 4H), 1.75 (m,
O
O
O
O
N
O
O
N
O
6H), 1.44 (m, 6H).
NH2
2.2.2. Synthesis of N,N0-dicyclohexyl-(1-nitro)perylene-3,4,9,10-
tetracarboxylic acid bisimide 3
CAN, HNO3
CH2Cl2
Zn, CH3COOH
THF
NO2
Compound 2 (2.5 g,4.5 mmol), cerium (IV) ammonium nitrate
(CAN) (3 g, 5.5 mmol), nitric acid (3.25 mL, 80 mmol) and
dichloromethane (350 mL) were stirred at 25 ꢀC under N2 for 2 h.
The mixture was neutralized with 10%(w/w) KOH and extracted
with CH2Cl2. After the solvent was removed, the crude product
was purified by silica gel column chromatography with the eluent
O
N
2
O
O
N
3
O
O
O
1
O
O
N
O
O
O
N
N
O
O
N
O
O
N
O
O
O
H
O
acetylchloride, pyridine
THF
NH2
N
H
F-
N
N
H
F
O
N
O
O
O
N
O
O
N
O
AM-PDIs
Scheme 1. The synthetic route of AM-PDIs.
4
Scheme 2. Intermolecular Proton Transfer between AM-PDIs and the Fluoride Ion.

412
Z.J. Chen et al. / Dyes and Pigments 94 (2012) 410e415
Fig. 2. Partial 1HNMR spectra of sensor AM-PDIs in CDCl3 in the presence of 0 equiv, and 12 equiv of TBAF.
CH2Cl2 to afford compound 3 in 95% yield. compound 3: 1HNMR
(CDCl3): 8.74 (d, J ¼ 6.4 Hz, 1H),8.62e8.69 (m, 4H), 8.55 (d,
J ¼ 6.0 Hz, 1H), 8.18 (d, J ¼ 6.0 Hz, 1H), 5.00 (m, 2H), 2.54 (m, 4H),
1.47e1.91 (m, 14H), 1.34 (m, 2H).
a
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
2.2.3. Synthesis of N,N0-dicyclohexyl-(1-amino)perylene-3,4,9,10-
tetracarboxylic acid bisimide 4
Compound 3 (2.0 g, 3.3 mmol) was added to a previously
prepared solution of THF (40 mL) containing 4.8 g of Zn (70 mmol)
and aerated with ethylic acid(3 mL, 50 mmol). The reaction mixture
was stirred at 25 ꢀC under N2 for 12 h. After the removal of the
solvent and washing of the residue with 5% NaOH (30 mL ꢁ 3),
Compound 4 was obtained as purple solid in 95% yield. compound
4: 1HNMR(CDCl3): 8.77(d, J ¼ 8.4 Hz, 1H), 8.55e8.57(m, 2H),
0
2
4
6
8
10
12
F-(0-12equiv)
b
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
0
2
4
6
8
10
12
F-(0-12equiv)
Fig. 4. (a): Plot of the absorbance ratio of AM-PDIs between 681 nm and 530 nm
(A681nm/A497nm) vs concentration of Fꢂ in DCM. b: Plot of the emission intensity ratio of
AM-PDIs between 588 nm and 480 nm (I480 nm/I588 nm) vs concentration of Fꢂ in DCM.
Fig. 3. Partial infrared spectra of sensor AM-PDIs in the presence of 0 equiv, and 12
equiv of TBAF.

Z.J. Chen et al. / Dyes and Pigments 94 (2012) 410e415
413
8.39e8.40(m, 2H), 8.35(d, J ¼ 8.0 Hz, 1H), 8.07(s, 1H), 5.15(s, 2H),
4.34e4.37(m, 2H), 1.73e1.79(m, 12H), 1.22e1.28(m, 8H).
change from red to blackish green in ambient light, which could
be observed by naked eyes. In the absence of anions, the
maximum absorption wavelength of AM-PDIs is at about
530 nm. Upon progressive addition of TBAF, the peak at 530 nm
decreased gradually, and a large bathochoromic shift (151 nm) of
the maximum could be observed and increased (Fig. 1a),
meanwhile a totally new band at 681 nm is developed with two
clear isosbestic points at 564 nm and 455 nm, which indicated
the formation of new compound. Upon excitation at 455 nm,
the free sensor showed an intense emission at 588 nm, however,
the addition of the flourion led to a drastic decrease at 588 nm
and simultaneous appearance of a new emission band at
480 nm, attributed to the local emission(LE) [35], as shown in
the Fig. 1b.
As a result, the sensor provided a ratiometric fluorescent
response (I480/I588) to F anions. Thinking of the above facts,
a possible explanation for the F.
2.2.4. Synthesis of AM-PDIs
Acetylchloride (0.24 g, 3 mmol) was dissolved in THF (10 mL)
and added dropwise to a solution of THF (40 mL) containing
0.57 g of compound 4 (1 mmol) and 0.3 mL pyridine (3.6 mmol).
The reaction mixture was stirred at 55 ꢀC under N2 for 12 h. After
the solvent was removed, This crude product was purified by
silica gel column chromatography with 1:100 CH2Cl2:CH3OH to
give 0.2
g
(33%) of
a
red solid. compound AM-PDIs:
1HNMR(CDCl3): 8.93(s, 1H), 8.32(d, J ¼ 6.8 Hz, 1H), 8.18(d,
J ¼ 9.6 Hz, 1H), 7.96(d, J ¼ 7.2 Hz, 1H), 7.87(d, J ¼ 6.0 Hz, 1H),
7.69(d, J ¼ 7.2 Hz, 1H), 7.38(m, 1H), 7.17(m, 1H), 4.88(m, 2H),
2.41e2.48(m, 8H), 1.61e1.64(m, 6H), 1.25e1.38(m, 6H). MS: m/
z ¼ 611.2411, (calcd. 611.2420).
anion-triggered spectroscopic changes was the intermolecular
proton transfer (IPT) process between the amide moiety and fluo-
ride ion and its change from electronically neutral (PDIseNHeAC)
without a fluoride ion to negatively charged (PDIs-Nꢂ-AC) with
a fluoride ion [36] (Scheme 2).
3. Result and discussion
n-Bu4NF (TBAF) as a fluoride source was gradually added to a
DCM solution of the sensor AM-PDIs. The deprotonated abilities
of sensor AM-PDIs with the fluoride ion were investigated by the
UVevis absorption and fluorescence spectra, when TBAF was
added to the DCM solution of sensor AM-PDIs, an obvious color
To confirm this assumption, 1HNMR titrations and infrared
spectrum were carried out (Fig. 2 and Fig. 3). It was found that the
amide NeH proton signal (8.93 ppm)-single peak and NeH
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
a
0.5
a
Sensor AM-PDIs
-
-
Sensor AM-PDIs +F
Sensor AM-PDIs+F +other anions
0.0
none
F
Cl
Br
I
400
500
600
700
800
900
Wavelength(nm)
b
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
b
35000
30000
25000
20000
15000
10000
5000
0
Sensor AM-PDIs
-
Sensor AM-PDIs+F +other anions
-
Sensor AM-PDIs+F
500
600
700
800
none
F
Cl
Br
I
Wavelength(nm)
Fig. 5. (a): Absorbance ratiometric response of AM-PDIs between 681 nm and 530 nm
to the halide ions (12 equiv). (b): Emission ratiometric response of AM-PDIs to the
halide ions (12 equiv). The emissions were at 588 nm and 480 nm and excited at
455 nm.
Fig. 6. a): UVeVis absorption spectra of sensor AM-PDIs (1 ꢁ 10ꢂ5 M) to F anions(12
equiv) in the presence of 12 equiv of each relevant analyte (Cl, Br, I) in DCM. (b):
Fluorescent spectra of sensor AM-PDIs(1 ꢁ 10ꢂ5 M) to F anions(12 equiv) in the
presence of 12 equiv of each relevant analytes (Cl, Br,I) in DCM.

414
Z.J. Chen et al. / Dyes and Pigments 94 (2012) 410e415
Fig. 7. Color (a, left) and fluorescence (b, right) change of sensor AM-PDIs (from left to right: AM-PDIs only; AM-PDIs þ Fꢂ; AM-PDIs þ Clꢂ; AM-PDIs þ Brꢂ; AM-PDIs þ Iꢂ).
stretching vibrational absorption(3294.93 cmꢂ1
)
disappeared
selective for fluoride anions over other halid ions. The large red
shift in the absorption and the ratiometric fluorescent response
render the sensor suitable for detection of F anions by simple
visual inspection.
with addition of Fꢂ, which confirmed the deprotonation of NeH
by Fꢂ.
Fig. 4a showed a nearelinear correlation of AM-PDIs between
intensity ratios of absorbance at 681 nm to those at 530 nm (A681
/
A530) vs fluoride ion concentration in DCM.This demonstrated the
potential utility of sensor AM-PDIs for calibrating and determining
fluoride ion concentration in DCM. Furthermore, a corresponding
correlation between emission ratiometric response of AM-PDIs at
580 nm and 488 nm (I488/I580) and fluoride ion concentration in
DCM was obtained in Fig. 4b, thus, AM-PDIs could also serve as
a ratiometric fluorescent sensor for Fꢂ. The linear equation was
found to be y ¼ 533.22 ꢁ 105x þ 25.309 (R ¼ 0.9652), where y was
the absorbance at 681 nm measured at a given F1 concentration
and x represented the concentration (10ꢂ5 mol/L) of F added.
According to IUPAC, the detection limit was determined from
three times the standard deviation of the blank signal (3s) as
Acknowledgements
This research was financially supported by the National Nature
Science Foundation of China (20672035) and Baihehua Group.
References
[1] Martínez-Máñez R, Sancenon F. Fluorogenic and chromogenic chemosensors
and reagents for anions. Chem Rev 2003;103:4419e76.
[2] Schmidtchen FP, Berger M. Artificial organic host molecules for anions. Chem
Rev 1997;97:1609e46.
[3] Li AF, Wang J-H, Wang F, Jiang Y-B. Anion complexation and sensing using
modified urea and thiourea-based receptors. Chem.Soc Rev 2010;39:3729e45.
[4] Liu W, Pin KM, Lee D. Conjugated polymer sensors built on p-extended bor-
asiloxane cages. J Am Chem Soc 2009;131:8703e7.
0.14 mM.
Sensor AM-PDIs was treated with all the halide ions to
investigate the selectivity. AM-PDIs showed a large ratiometric
response (A681/A530 ¼ 1.67, I480/I588 ¼ 1.54) for the fluoride
anion,while the other analytes only induced a minimum ratio-
metric response with A681/A530 < 0.01, I480/I588 < 0.01, as shown
in Fig. 5. These results indicate that the sensor is highly selective
to Fꢂ over other halide ions tested. The high selectivity to fluoride
anion may be because fluoride anion was a much stronger
hydrogen bond acceptor than other halide ions. Thus, only the
flouride anion could induceintermolecular proton transfer (IPT)
process between the amide moiety and fluoride ion while other
halide ions could not.
To examine whether sensor AM-PDIs could still retain the
sensing response to Fꢂ under the potential competition of relevant
analytes, the sensor was treated with Fꢂ in the presence of Clꢂ, Brꢂ
and Iꢂ. As displayed in Fig. 6a and Fig. 6b, all the relevant analytes
tested have virtually no influence on the detection of Fꢂ. Thus,
sensor AM-PDIs seemed to be useful for selectively sensing Fꢂ, even
with these relevant analytes. Notably, the big red shift combined
with large ratiometric absorbtion and fluorescent response
rendered the sensor suitable for detection of Fꢂ anions by simple
visual inspection (Fig. 7).
[5] Shao J, Yu D, Lin H, Lin H. Colorimetric recognizing of biologically important
anions based on anion-induced tautomerism of the sensor. J Mol Recognit
2008;21:425e30.
[6] Lee H, Lee JT, Hong J, Kim H. Visual detection of cyanide through intra-
molecular hydrogen bond. Chem Lett 2007;36:816e7.
[7] Martínez-Máñez R, Sancenon F. New advances in fluorogenic anion chemo-
sensors. J Fluoresc 2005;15:267e85.
[8] Suksai C, Tuntulani T. Chromogenic anion sensors. Chem Soc Rev 2003;32:
192e202.
[9] Kong FP, Liu QJ, Wu X, Wang Z, Chen Q, Chen LS. 2-(4-Formylphenyl)phe-
nanthroimidazole as
a colorimetric and Fluorometric probe for selective
fluoride ion sensing. J Fluoresc 2005;15:267e84.
[10] Kirk KL. Biochemistry of the elemental halogens and inorganic halides. New
York: Plenum Press; 1991.
[11] Riggs BL. Bone and mineal research. Annual 2. Amsterdam: Elsevier; 1984.
[12] Barbier O, Arreola-Mendo L. Molecular mechanisms of fluoride toxicity. Chem
Biol Interact 2010;188:319e33.
[13] Wade CR, Broomsgrove AEJ, Aldridge S, GabbaÏ FP. Fluoride ion complexation
and sensing using Organoboron Compounds. Chem Rev 2010;110:3958e84.
[14] Ren J, Wu Z, Zhou Y, Li Y, Xu ZX. Colorimetric fluoride sensor based on 1,8-
naphthalimide derivatives. Dyes Pigm 2011;91:442e5.
[15] Ren J, Zhao X-L, Wang Q-C, Ku C-F, Qu D-H, Chang C-P, et al. New fluoride
fluorescent chemosensors based on perylene derivatives linked by urea. Dyes
Pigm 2005;64:193e200.
[16] JiangY, Zhao H, LinYQ, ZhuNN, Ma YR, Mao LQ. Colorimetricdetection of Glucose
in Rat Brain using Gold Nanoparticles. Angew Chem.Int Ed 2010;122:4910e4.
[17] Zhang JF, Lim CS, Bhuniya S, Cho BR, Kim JS. A highly selective colorimetric
and ratiometric two-photon fluorescent probe for fluoride ion detection. Org
Lett 2011;13:1190e3.
[18] Sokkalingam P, Lee C-H. Highly sensitive fluorescence “Turn-On” indicator for
fluoride anion with remarkable selectivity in organic and Aqueous Media.
J Org Chem 2011;76:3820e8.
[19] Cametti M, Rissanen K. Recognition and sensing of fluoride anion. Chem
Commun 2009;20:2809e29.
4. Conclusions
In summary, we have designed and synthesized sensor AM-
PDIs as a novel colorimetric and ratiometric fluorescent sensor
for fluoride anions based on the PDIs rationally. The sensor
exhibited a large red shift(151 nm) in absorption and the detection
[20] Qu Y, Hua JL, Tian H. Colorimetric and ratiometric red fluorescent chemo-
sensor for fluoride ion based on diketopyrrolopyrrole. Org Lett 2010;12:
3320e3.
[21] Huang C, Barlow S, Marder SR. Perylene-3,4,9,10-tetracarboxylic acid Dii-
mides: synthesis, Physical properties, and use in organic Electronics. J Org
Chem 2011;76:2386e407.
limit was calculated to be 0.14 mM. In addition, the sensor is highly

Z.J. Chen et al. / Dyes and Pigments 94 (2012) 410e415
415
[22] Ahrens MJ, Fuller MJ, Wasielewski MR. Cyanated Perylene-3,4-dicarboximides
and Perylene-3,4:9,10-bis(dicarboximide): Facile Chromophoric Oxidants for
Organic Photonics and electronics. Chem Mater 2003;15:2684e6.
[23] Gvishi R, Reisfeld R, Burshtein Z. Spectroscopy and laser action of the “red
perylimide dye” in various solvents. Chem Phys Lett 1993;213:338e44.
[24] Anthony JE. Small-Molecule, Nonfullerene acceptors for polymer bulk heter-
ojunction organic photovoltaics. Chem Mater 2011;23:583e90.
[30] Soh N, Ariyoshi T, Fukaminato T, Nakajima H, Nakano K, Imato T. Swallow-
tailed perylene derivative: new tool for fluorescent imaging of lipid
hydroperoxides. Org Biomol Chem 2007;5:3762e8.
[31] Ito F, Ariyoshi T, Soh N, Kakiuchi T, Inoue T, Imato T, et al. Dynamic Behavior of
a
a
fluorescent probe, a Swallow-tailed perylene derivative for detecting
hydroperoxides. Chem Lett 2008;37:1202e3.
[32] Ruan Y-B, Li A-F, Zhao J-S, Shen J-S, Jiang Y-B. Specific Hg2þ-mediated per-
ylene bisimide aggregation for highly sensitive detection of cysteine. Chem
Commun 2010;46:4938e40.
[25] Seybold G, Wagenblast G. New perylene and violanthrone dyestuffs for
fluorescent collectors. Dyes Pigm 1989;11:303e17.
[26] Brooks AJ, Antonio F, Michael RW, Tobin JM. Tuning orbital energetics in
arylene diimide semiconductors. materials design for ambient stability of n-
type charge transport. J Am Chem Soc 2007;129:15259e78.
[33] Miyake Y, Togashi H, Tashiro M, Yamaguchi H, Oda S, Kudo M, et al. MercuryII-
Mediated formation of ThymineꢂHgIIꢂThymine Base Pairs in DNA Duplexes.
J Am Chem Soc 2006;128:2172e3.
[27] Feng LH, Chen ZB. Screening mercury (II) with selective fluorescent chemo-
sensor. Sensors Actuators B: Chem 2007;122:600e4.
[28] Yan LW, Yang L, Lan JB, You JS. A new perylene diimide-based colorimetric
and fluorescent sensor for selective detection of Cu2þ cation. Sci China Ser B:
Chem 2009;52:518e22.
[34] He XR, Zhong ZF, Guo YB, Lv J, Xu JL, Zhu M, et al. Gold Nanoparticle-based
monitoring of the reduction of Oxidized to Reduced Glutathione. Langmuir
2007;23:8815e9.
[35] Cao XW, Lin WY, Yu QX, Wang JX. Ratiometric sensing of fluoride anions
based on a bODIPY-coumarin Platform. Org Lett 2011;13:6098e101.
[29] Soh N, Ariyoshi T, Fukaminato T, Nakano K, Masahiro Irie, Toshihiko Imato.
Novel fluorescent probe for detecting hydroperoxides with strong emission in
the visible range. Bioorg Med Chem Lett 2006;16:2943e6.
[36] Liu B, Tian H. A ratiometric fluorescent chemosensor for fluoride ions
based on a proton transfer signaling mechanism. J Mater Chem 2005;15:
2681e6.