A dansyl-rhodamine chemosensor for Fe(III) based on off-on FRET

Article abstract of DOI:10.1016/j.saa.2014.03.002

A novel fluorescent chemosensor bearing a rhodamine and a dansyl moiety was developed for highly selective detection of Fe³⁺ based on fluorescence resonance energy transfer (FRET) mechanism. Binding of Fe ³⁺ to the chemosensor induce

Full text of DOI:10.1016/j.saa.2014.03.002

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (2014) 475–480
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
A dansyl–rhodamine chemosensor for Fe(III) based on off–on FRET
⇑
Jingyu Piao, Jia Lv, Xin Zhou, Tong Zhao, Xue Wu
Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules, Ministry of Education, Yanbian University, Yanji, Jilin 133002, China
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
ꢀ
ꢀ
The chemosensor was synthesized
relatively in a simple way.
The skeleton of the chemosensor is
composed of a dansyl and rhodamine
group.
ꢀ
ꢀ
Off-on FRET was induced by Fe3+
binding to the chemosensor.
The chemosensor showed high
selectivity and sensitivity for Fe3+
.
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 27 August 2013
Received in revised form 29 January 2014
Accepted 1 March 2014
Available online 14 March 2014
A novel fluorescent chemosensor bearing a rhodamine and a dansyl moiety was developed for highly
selective detection of Fe3+ based on fluorescence resonance energy transfer (FRET) mechanism. Binding
of Fe3+ to the chemosensor induced spirolactam ring opening in the rhodamine moiety and subsequent
off–on FRET from the dansyl energy donor to the rhodamine energy acceptor due to the spectral overlap
between the emission of the dansyl moiety and the absorption of the ring opened rhodamine moiety.
Job’s plot analysis indicated a 1:1 binding stoichiometry between the chemosensor and Fe3+. The associ-
ation constant was estimated to be 2.72 Â 103 MÀ1 according to the Benesi–Hildebrand method. With the
feature of easy synthesis, simple structural skeleton and excellent sensing ability, the newly synthesized
chemosensor provided the potential for applying as a highly selective fluorescent probe in complex sam-
ples containing various competitive metal ions and developing other metal ion chemosensors to fulfill
various needs of biological and environmental field.
Keywords:
Rhodamine
Dansyl
FRET
Fe3+
Chemosensor
Ó 2014 Elsevier B.V. All rights reserved.
Introduction
transportation and energy metabolism [5,6]. Unbalanced iron con-
tent within human body can cause a variety of diseases, such as
Highly selective and sensitive detection of heavy metal and
transition metal ions, have attracted considerable attention in
recent years because of their important roles in environmental
and biological systems [1–4]. As one of the most essential trace
metals within human body, iron ion plays crucial roles in protein
synthesis and structural maintenance, enzymatic reaction, oxygen
iron deficiency anemia [7–10]. Some recent researches have even
revealed that Fe3+ could involve in some neurodegenerative
diseases, such as Parkinson’s and Alzheimer’s disease [11–14]. Re-
searches on developing Fe3+ sensing platforms have been of great
interest and challenge. To date, most Fe3+ sensing assays depend
on the fluorescence quenching mechanism because of the
paramagnetic nature of ionic iron, which inevitably give high back-
ground signals [15,16]. Relatively, there are only a few fluorescent
chemosensors reported for detecting Fe3+ based on fluorescent
⇑
Corresponding author. Tel.: +86 4332732299; fax: +86 4332732456.
E-mail address: wuxue@ybu.edu.cn (X. Wu).
http://dx.doi.org/10.1016/j.saa.2014.03.002
1386-1425/Ó 2014 Elsevier B.V. All rights reserved.

476
J. Piao et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (2014) 475–480
‘‘turn on’’ mechanism [17–19]. Thus, there is still an intense de-
mand for developing highly selective and sensitive Fe3+ chemosen-
sors to satisfy various needs of environmental and biological fields.
A certain number of rhodamine based fluorescent chemosen-
sors have been developed for monitoring various metal ions of bio-
logically and environmentally importance, due to their excellent
photophysical properties such as high absorption coefficient, high
fluorescence quantum yield, good photostability and relatively
long emission wavelength [20–22]. The equilibrium between the
spirolactam (non-fluorescent) and the spirocyclic form (fluores-
cent) makes the rhodamine framework an ideal off–on fluorescent
Experimental
Materials and instrumentation
All chemicals were obtained from commercial suppliers and
used without further purification unless otherwise mentioned.
Absorption spectra were recorded with a Shimadzu UV-2550 spec-
trophotometer (Shimadzu, Japan). Fluorescence spectra were taken
on RF-5301PC spectrofluorophotometer (Shimadzu, Japan). The 1
H
NMR and 13C NMR spectra were recorded on a Bruker AV-300 spec-
trometer (300 MHz for 1H and 75 MHz for 13C) (Bruker, Switzer-
land). Mass spectra were measured on an Agilent 7500a ICP–MS
Mass spectrometer (Agilent, USA). IR spectra were obtained with
a Shimadzu FT-IR Prestige-21 instrument (Shimadzu, Japan) (KBr
pressed disc method). The silica gel (J&K Scientific Ltd., Beijing, Chi-
na) used for flash chromatography was 200–300 mesh. Rhodamine
B, ethylenediamine, dansyl chloride, TsCl, triethylamine were pur-
chased from Aladdin (Shanghai, China) and used without further
purification. All cationic compounds such as perchlorate of Ag+,
probe, especially for metal ions, such as Cu2+, Hg2+, Pb2+, Cr3+, Cd2+
,
Zn2+. However, the small Stokes shift (ꢁ30 nm) of the fluorescent
probe tends to induce serious fluorescence quenching and Rayleigh
scattering, which leads to severe detection errors. To solve the prob-
lem, FRET was chosen and applied in many detection platforms for
its convenience to modify the excitation source [23–29]. FRET is de-
fined as a nonradiative energy transfer process in which the excited
donor energy is transferred to an acceptor unit without photoemis-
sion. Since the pseudo-Stokes shift of FRET based probes are larger
than the Stokes shift of either the donor or acceptor dyes, the fluo-
rescence detection errors can be efficiently avoided [30]. Although
rhodamine based Fe3+ chemosensors have been intensively studied,
but off–on FRET based fluorescent sensors containing tren-spaced
rhodamine are still rare.
Al3+, Ba2+, Ca2+, Cu2+, Fe2+, Cr3+, Fe3+, Hg2+, K+, Mg2+, Ni2+, Pb2+
,
Zn2+ were obtained from Strem Chemicals (Newburyport, MA,
USA).
Synthesis
In this research, we have designed and synthesized a new fluo-
rescent probe for Fe3+ based on off–on FRET. The skeleton of the
probe was composed of a rhodamine dye and a dansyl group
[22,31–33], which displayed significant spectral overlap between
the emission spectra of the dansyl energy donor and the absorption
Compound 1
Under nitrogen, a solution of rhodamine B (0.5 g, 1.0 mmol),
ethanediamine (90 mg, 1.5 mmol) and methanol (40 mL) was
heated at 80 °C for 5 h. After cooling to room temperature, the sol-
vent was evaporated under reduced pressure. Then, the resulting
mixture was dissolved by adding CH2Cl2 (100 mL) and water
(200 mL). After removing the organic layer, the residue was dried
over anhydrous Na2SO4 and filtered. The solvent was evaporated
under reduced pressure, and the crude product was purified by
column chromatography (ethyl acetate:ethanol = 1:3) to give
0.43 g of saffron yellow 1 in 85% yield. 1H NMR (300 MHz, CDCl3)
d 7.91 (dd, J = 5.6, 3.0 Hz, 1H), 7.45 (dd, J = 5.6, 3.1 Hz, 2H), 7.10
spectra of the rhodamine energy acceptor upon binding with Fe3+
.
The binding of Fe3+ causes structural change in the rhodamine moi-
ety and induces the spirolactam ring opening, facilitating the intra-
molecular FRET from donor to acceptor in the probe [23,34]. To the
best of our knowledge, this is the first time that a compound con-
taining a rhodamine (energy acceptor) and a dansyl group (energy
donor) has been used as a fluorescent probe for Fe3+ based on FRET.
Scheme 1. Synthesis of chemosensor 2.

J. Piao et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (2014) 475–480
477
Fig. 1. Normalized absorption and emission spectra of both donor and acceptor
moiety. The spectral overlap between the emission of the donor and the absorption
of the acceptor is marked with oblique line.
(dd, J = 5.5, 3.0 Hz, 1H), 6.43 (d, J = 8.8 Hz, 2H), 6.37 (d, J = 2.4 Hz,
2H), 6.27 (dd, J = 8.8, 2.5 Hz, 2H), 3.33 (q, J = 7.1 Hz, 8H), 3.19
(t, J = 6.6 Hz, 2H), 2.39 (t, J = 6.6 Hz, 2H), 1.16 (t, J = 7.0 Hz, 12H).
Compound 2
In an ice bath, a solution of dansyl chloride (100 mg, 1.0 mmol)
in anhydrous dichloromethane (10 mL) was added slowly to a mix-
ture of compound 1 and triethylamine (0.5 mL) in anhydrous
dichloromethane (20 mL), and then the resulting mixture was stir-
red for 0.5 h at room temperature. With the similar workup proce-
dures as described in synthesis of compound 1, a crude product of
compound 2 was obtained. And the crude product was purified by
column chromatography (ethyl acetate:petroleum ether = 1:1) to
give 120 mg of saffron yellow 2 in 82% yield. 1H NMR (300 MHz,
CDCl3) d 8.48 (d, J = 8.5 Hz, 1H), 8.29 (d, J = 8.7 Hz, 1H), 8.11 (d,
J = 8.5 Hz, 1H), 7.89 (d, J = 6.4 Hz, 1H), 7.45 (ddd, J = 24.1, 16.5,
8.7 Hz, 4H), 7.03 (d, J = 7.5 Hz, 1H), 6.91 (d, J = 7.8 Hz, 1H), 6.28
(d, J = 2.5 Hz, 2H), 5.95 (dd, J = 8.9, 2.5 Hz, 2H), 5.84 (d, J = 8.9 Hz,
2H), 3.29 (q, J = 7.0 Hz, 8H), 3.21–3.16 (t, 2H), 2.78 (s, 6H), 2.63
(t, J = 9.9, 4.6 Hz, 2H), 1.14 (t, J = 7.0 Hz, 12H). 13C NMR (75 MHz,
CDCl3) d 169.80, 153.37, 152.66, 151.19, 148.35, 134.28, 132.31,
129.67, 129.46, 128.53, 123.79, 121.76, 119.05, 114.73, 107.63,
103.76, 97.21, 78.06, 75.91, 76.43, 76.43, 65.18, 45.02, 43.90,
39.47, 12.19. MS: [M+] at 718.
Fig. 2. Absorption (a) and emission (b) spectra of chemosensor 2 (10
addition of various metal ion (10 equiv) in ethanol solution. kex = 420 nm.
l
M) upon
Procedures for metal ion sensing
A stock solution of compound 2 (1.0 Â 10À5 M) was prepared in
ethanol. Stock solutions of the metal perchlorate salts were pre-
pared in ethanol with a concentration of 2.0 Â 10À3 M. Each time
a stock solution of compound 2 (2.0 mL) and less than 100 lL of
a metal ion stock solution were filled in a quartz cell of 1 cm optical
path length using a micro-pipette for spectral measurements. For
all measurements of fluorescence spectra, excitation wavelength
was 420 nm unless otherwise mentioned and the temperature is
20 °C.
Compound 3
Results and discussion
In an ice bath, a solution of TsCl (39.3 mg, 1.0 mmol) in anhy-
drous dichloromethane (10 mL) was added slowly to a mixture of
compound 1 and triethylamine (0.5 mL) in anhydrous dichloro-
methane (20 mL), and then the resulting mixture was stirred for
0.5 h at room temperature. With the similar workup procedures
as described in synthesis of compound 1, a crude product of com-
pound 3 was obtained. And the crude product was purified by col-
umn chromatography (ethyl acetate:petroleum ether = 1:1) to give
saffron yellow 3 in 83% yield. 1H NMR (300 MHz, CDCl3) d 7.89 (dd,
J = 6.2, 2.5 Hz, 1H), 7.66 (d, J = 8.0 Hz, 2H), 7.45 (dd, J = 5.4, 2.9 Hz,
2H), 7.20 (d, J = 8.0 Hz, 2H), 7.08–7.00 (m, 1H), 6.35 (d, J = 1.8 Hz,
2H), 6.24 (d, J = 8.8 Hz, 2H), 6.16 (dd, J = 8.9, 1.8 Hz, 2H), 6.03 (t,
J = 4.6 Hz, 1H), 3.33 (q, J = 7.0 Hz, 8H), 3.20–3.13 (m, 2H), 2.76
(dd, J = 10.3, 5.0 Hz, 2H), 2.36 (s, 3H), 1.59 (s, 2H), 1.17 (t,
J = 7.0 Hz, 13H). 13C NMR (75 MHz, CDCl3) d 169.28, 153.22,
152.83, 148.50, 142.31, 132.41, 129.91, 129.02, 127.87, 126.74,
123.42, 122.46, 107.80, 104.08, 97.37, 76.84, 76.20, 65.15, 43.96,
43.24, 39.74, 21.05, 12.19. MS: [M+] at 638.9.
As shown in Scheme 1, compound 2 (chemosensor 2) was fac-
ilely prepared by a simple condensation reaction between com-
pound 1 and dansyl chloride at room temperature in 82% yield.
The structure of chemosensor 2 was confirmed by NMR (1H and
13C) spectra, ESI mass spectrometry and IR spectroscopy (support-
ing information). The 1H NMR spectrum of chemosensor 2 dis-
played a triplet (12H) at 1.14 ppm corresponding to the methyl
protons, a singlet (6H) at 2.78 ppm corresponding to the methyl
protons, two triplet (2H each) at 2.60–2.65 and 3.18–3.21 corre-
sponding to CH2 of ethanediamine moiety, a quarlet (8H) at
3.25–3.32 ppm corresponding to the methylene protons, three
mutiplets (2H each) at 5.83–5.93, 5.94–5.97 and 6.27–6.28 ppm
corresponding to aromatic protons, seven multiplets (1H, 1H, 5H,
1H, 1H, 1H and 1H respectively) at 6.90–6.92, 7.02–7.04, 7.38–
7.51, 7.88–7.90, 8.09–8.12, 8.28–8.31 and 8.47–8.50 ppm corre-
sponding to aromatic and NH protons (Fig. S2). Mass spectrum of
chemosensor 2 showed a parent ion peak at m/z 718 (Fig. S4). A

478
J. Piao et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (2014) 475–480
Fig. 3. Color (top) and fluorescence (bottom) images of chemosensor 2 (10
lM) upon addition of various metal ion in ethanol solution. (For interpretation of the references to
color in this figure legend, the reader is referred to the web version of this article.)
Scheme 2. Proposed mechanism for chemosensor 2 + Fe3+ complex.
stretching band at 1678 cmÀ1 corresponding to the C@O group was
observed in the IR spectrum of chemosensor 2 (Fig. S5). There was
no absorption band of free hydroxyl group in the IR spectrum,
which confirmed that the condensation reaction has been success-
fully occurred. Free chemosensor 2 solution is colorless and
nonfluorescent, which indicated the rhodamine moiety exist in
its ring-closed spirolactam form.
The absorption and emission spectra of individual components
of chemosensor 2 are shown in Fig. 1. The dansyl moiety has strong
and broad emission in the visible range (450–650 nm) which cov-
ers a part of the absorption of the ring-opened rhodamine moiety,
providing the favorable condition for FRET. The ethanediamine
moiety acts as both a linking ligand to connect the rhodamine
and dansyl moiety in close proximity and a chelating ligand to pro-
vide crucial chelating sites for Fe3+ by coordination with the dansyl
moiety [35,36].
The binding behavior of chemosensor 2 towards various metal
ions (Ag+, Al3+, Ba2+, Ca2+, Cu2+, Fe3+, Hg2+, K+, Mg2+, Ni2+, Pb2+
,
Zn2+, Fe2+, Cr3+) was studied by fluorescence and UV–vis spectros-
copy. As shown in Fig. 2a, a characteristic absorption peak of the
ring-opened rhodamine moiety was appeared at 555 nm upon
forming 2-Fe3+ complex. While, other metal ions did not induce
any distinct spectral changes in the visible region, implying that
chemosensor 2 has no special binding ability for these metal ions.
Upon excitation at 420 nm, a strong emission peak at 578 nm was
observed in addition to the relatively weak emission at about
507 nm in the fluorescence spectrum of the 2-Fe3+ complex
(Fig. 2b), indicating the FRET occurring from the dansyl energy do-
nor to the rhodamine energy acceptor. However, for other metal
ions, there was no other emission peak observed except the rela-
tively weak emission peak at 507 nm which were produced from
the dansyl moiety. More than 10-fold fluorescence enhancement
was estimated in the 2-Fe3+ complex, according to the ratio of
the fluorescence intensity of the energy acceptor at 578 nm to that
of the energy donor at 507 nm. Moreover, upon irradiation at
555 nm, strong fluorescence emission at around 578 nm in the
spectrum of the 2-Fe3+ complex was observed, confirming the spi-
rolactam ring opening in the rhodamine moiety (data not shown).
Color and fluorescence images of the corresponding metal ion test-
ing solutions showed that Fe3+ was the only ion that changed the
color of chemosensor 2 solution from colorless to pink and fluores-
cence from green to brown as shown in Fig. 3, which implied that
the rhodamine moiety is in its ring-opened spirocyclic form.
Fig. 4. Absorption (a) and fluorescence (b) change of chemosensor 2 (10 lM) upon
addition of Fe3+ (10 equiv) in the presence and absence of other metal ions
(10 equiv) in ethanol solution. kex = 420 nm. Red bars and black bars represent the
2-Fe3+ complex without and with other metal ions, respectively. (For interpretation
of the references to color in this figure legend, the reader is referred to the web
version of this article.)
To further confirm the fluorescence from the rhodamine moiety
was actually due to FRET from the dansyl energy donor to the rho-
damine energy acceptor, we replaced the dansyl group with a tosyl
one in chemosensor 2 to obtain compound 3 through the similar
condensation way as shown in Scheme 1. Interestingly, compound
3 (chemosensor 3) also exhibited good sensing ability towards Fe3+
as that shown by chemosensor 2 (Figs. S10 and S11). However, extre-
mely different sensing mechanism between the two chemosensors

J. Piao et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (2014) 475–480
479
Fig. 5. Absorption (a) and fluorescence (b) titration spectra of chemosensor 2 (10 l
M) upon addition of Fe3+ (0–15 equiv) in ethanol solution. kex = 420 nm. (a) Inset: Job’s plot
for determining the stoichiometry of chemosensor 2 and Fe3+. (b) Inset: plot of fluorescence intensity at 578 nm as a function of Fe3+ concentration. The detection limit (DL) of
Fe3+ using chemosensor 2 was determined from the following equation: DL = K Â SD/S, where K = 3; SD is the standard deviation of the blank solution; S is the slope of the
calibration curve. DL = 1.05 Â 10À6 M.
seems exist. In the case of 3-Fe3+ complex, the fluorescence from
the rhodamine moiety could only be observed when excited at
555 nm (absorption of the rhodamine moiety with spirocyclic
form) other than other wavelength which implied that there was
no FRET between the tosyl moiety and the rhodamine one since
the tosyl moiety has no characteristic absorption in the visible
region at all. Thus, we can confirm that the fluorescence of the
2-Fe3+complex was due to FRET from the dansyl energy donor to
the rhodamine energy acceptor. Although the FRET efficiency in
the system was relatively low (around 50%, see supporting infor-
mation), but the fluorescence dual-switch (two different excitation
wavelengths of 420 and 555 nm) feature may find its superiority in
complex sample solution, such as living cell imaging [37,38], by
providing double evidences in one time.
10 equiv of Fe3+ and 10 equiv of other metal ions (Ag+, Al3+, Ba2+
,
Ca2+, Cu2+, Hg2+, K+, Mg2+, Ni2+, Pb2+, Zn2+, Fe2+, Cr3+) separately,
and the resulting individual test solution was analyzed by
UV–Vis and fluorescence spectrophotometer. As displayed in
Fig. 4, there was no significant spectral change for the 2-Fe3+ com-
plex with and without other metal ions, which confirmed that
chemosensor 2 can be used as a selective probe for Fe3+ in the pres-
ence of other metal ions in both colorimetric and fluorescent way.
Absorption and fluorescence titrations of chemosensor 2 were
conducted to monitor the spectral changes in accordance with
the amount of Fe3+. The UV–vis spectra (Fig. 5a) exhibited that
the absorption at 555 nm was gradually increased with the addi-
tion of Fe3+ (0–15 equiv), accompanied with visible color change
in corresponding test solution. Job’s plot analysis showed that
the binding stoichiometry between chemosensor 2 and Fe3+ was
1:1 (Fig. 5a, inset). The emission band centered at 578 nm was also
gradually increased with the increasing amounts of Fe3+ and
reached a plateau after the addition of 15 equiv of Fe3+ (Fig. 5b).
And the association constant of 2.72 Â 103 MÀ1 was obtained using
According to the sensing performance of chemosensor 2 for
Fe3+, the possible binding mechanism was proposed as shown in
Scheme 2. The IR spectra showed that the amide carbonyl peak
(1678 cmÀ1) disappeared after Fe3+ was added (Fig. S12), which
provide evidence that the amide carbonyl O of chemosensor 2 is
actually involved in coordination with metal ions. The binding pro-
cess of chemosensor 3 with Fe3+ is expected to be in the similar
way as that shown by chemosensor 2.
the Benesi–Hildebrand method by plotting 1/D ]
F against 1/[Fe3+
for chemosensor 2 and Fe3+ (Fig. S13). Moreover, nearly linear
relationship between the fluorescence change and Fe3+ concentra-
The selectivity of chemosensor 2 for Fe3+ over other metal ions
was further evaluated by performing interference experiments in
ethanol solution. Chemosensor 2 was mixed with a mixture of
tion in the range of 10–150
detection limit of 1.05
mentioned in the literatures [39–41].
lM was achieved (Fig. 5b, inset), with a
lM, which is comparable with that

480
J. Piao et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (2014) 475–480
[13] D.J. Bonda, H.G. Lee, J.A. Blair, X.W. Zhu, G. Perry, M.A. Smith, Metallomics 3
Conclusions
(2011) 267–270.
[14] A.S. Pithadia, M.H. Lim, Curr. Opin. Chem. Biol. 16 (2012) 67–73.
[15] J.L. Bricks, A. Kovalchuk, C. Trieflinger, M. Nofz, M. Buschel, A.I. Tolmachev, J.
Daub, K. Rurack, J. Am. Chem. Soc. 127 (2005) 13522–13529.
[16] J.P. Sumner, R. Kopelman, Analyst 130 (2005) 528–533.
[17] M.Y. She, Z. Yang, B. Yin, J. Zhang, J. Gu, W.T. Yin, J.L. Li, G.F. Zhao, Z. Shi, Dyes
Pigments 92 (2012) 1337–1343.
[18] S.R. Liu, S.P. Wu, Sensor. Actuat. B-Chem. 171 (2012) 1110–1116.
[19] M.-R. Huang, S.-J. Huang, X.-G. Li, J. Phys. Chem. C 115 (2011) 5301–5315.
[20] M.H. Lee, T. Van Giap, S.H. Kim, Y.H. Lee, C. Kang, J.S. Kim, Chem. Commun. 46
(2010) 1407–1409.
[21] Z. Yang, M.Y. She, B. Yin, J.H. Cuo, Y.Z. Zhang, W. Sun, J.L. Li, Z. Shi, J. Org. Chem.
77 (2012) 1143–1147.
[22] M.H. Lee, H.J. Kim, S. Yoon, N. Park, J.S. Kim, Org. Lett. 10 (2008) 213–216.
[23] H.B. Yu, Y. Xiao, H.Y. Guo, X.H. Qian, Chem.-Eur. J. 17 (2011) 3179–3191.
[24] Y.L. Liu, X. Lv, Y. Zhao, M.L. Chen, J. Liu, P. Wang, W. Guo, Dyes Pigments 92
(2012) 909–915.
In summary, a new fluorescent probe containing a rhodamine
energy acceptor and a dansyl energy donor was synthesized and
applied for selective detection of Fe3+ based on FRET off–on mech-
anism. The success of off–on FRET from the dansyl energy donor to
the rhodamine energy acceptor not only drastically reduced back-
ground signal by enlarging the pseudo-Stokes shift but also
provided a good structural skeleton for designing Fe3+ chemosen-
sor for more widely use. In addition, the relatively high selectivity
and sensitivity for Fe3+ over other metal ions showed the possibil-
ity for potential use in complex samples containing various
competitive metal ions.
[25] D. Maity, D. Karthigeyan, T.K. Kundu, T. Govindaraju, Sensor. Actuat. B-Chem.
176 (2013) 831–837.
Acknowledgment
[26] A. Coskun, E.U. Akkaya, J. Am. Chem. Soc. 127 (2005) 10464–10465.
[27] W.Y. Lin, L. Yuan, L.L. Long, C.C. Guo, J.B. Feng, Adv. Funct. Mater. 18 (2008)
2366–2372.
[28] Z.P. Liu, C.L. Zhang, W.J. He, Z.H. Yang, X.A. Gao, Z.J. Guo, Chem. Commun. 46
(2010) 6138–6140.
We acknowledge the Natural Science Foundation of China
(NSFC Nos. 21065013 and 21165019) for support of this work.
[29] Z.X. Han, X.B. Zhang, L. Zhuo, Y.J. Gong, X.Y. Wu, J. Zhen, C.M. He, L.X. Jian, Z.
Jing, G.L. Shen, R.Q. Yu, Anal. Chem. 82 (2010) 3108–3113.
[30] S.R. Adams, A.T. Harootunian, Y.J. Buechler, S.S. Taylor, R.Y. Tsien, Nature 349
(1991) 694–697.
[31] M.W. Piepkorn, D. Lagunoff, G. Schmer, Arch. Biochem. Biophys. 205 (1980)
315–322.
Appendix A. Supplementary material
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.saa.2014.03.002.
[32] J. Fan, M. Hu, P. Zhan, X. Peng, Chem. Soc. Rev. 42 (2013) 29–43.
[33] B.E. Leonard, N.N. Osborne, in: N. Marks, R. Rodnight (Eds.), Research Methods
in Neurochemistry, Springer, US, 1975, pp. 443–462.
References
[34] A. Ben Othman, J.W. Lee, J.S. Wu, J.S. Kim, R. Abidi, P. Thuery, J.M. Strub, A. Van
Dorsselaer, J. Vicens, J. Org. Chem. 72 (2007) 7634–7640.
[35] L. Dong, C. Wu, X. Zeng, L. Mu, S.F. Xue, Z. Tao, J.X. Zhang, Sensor. Actuat. B-
Chem. 145 (2010) 433–437.
[36] L.Z. Zhang, J.Y. Wang, J.L. Fan, K.X. Guo, X.J. Peng, Bioorg. Med. Chem. Lett. 21
(2011) 5413–5416.
[37] N.R. Chereddy, K. Suman, P.S. Korrapati, S. Thennarasu, A.B. Mandal, Dyes
Pigments 95 (2012) 606–613.
[38] B. Bag, B. Biswal, Org. Biomol. Chem. 10 (2012) 2733–2738.
[39] Y. Wei, Z. Aydin, Y. Zhang, Z. Liu, M. Guo, ChemBioChem 13 (2012) 1569–1573.
[40] S. Sen, S. Sarkar, B. Chattopadhyay, A. Moirangthem, A. Basu, K. Dhara, P.
Chattopadhyay, Analyst 137 (2012) 3335–3342.
[1] M. Dutta, D. Das, Trac-Trend. Anal. Chem. 32 (2012) 113–132.
[2] A.P. de Silva, H.Q.N. Gunaratne, T. Gunnlaugsson, A.J.M. Huxley, C.P. McCoy, J.T.
Rademacher, T.E. Rice, Chem. Rev. 97 (1997) 1515–1566.
[3] D.W. Domaille, E.L. Que, C.J. Chang, Nat. Chem. Biol. 4 (2008) 168–175.
[4] X.G. Li, Y.W. Liu, M.R. Huang, S. Peng, L.-Z. Gong, M.G. Moloney, Chem.-Eur. J.
16 (2010) 4803–4813.
[5] B. D’Autreaux, N.P. Tucker, R. Dixon, S. Spiro, Nature 437 (2005) 769–772.
[6] J.F. Collins, J.R. Prohaska, M.D. Knutson, Nutr. Rev. 68 (2010) 133–147.
[7] D. Galaris, V. Skiada, A. Barbouti, Cancer Lett. 266 (2008) 21–29.
[8] T. Thum, S.D. Anker, Lancet 370 (2007) 1906.
[9] R.S. Ajioka, J.P. Kushner, Blood 101 (2003) 3351–3354.
[10] J.D. Haas, T. Brownlie, J. Nutr. 131 (2001) 676s–688s.
[11] J.R. Burdo, J.R. Connor, Biometals 16 (2003) 63–75.
[12] J.R. Burdo, D.A. Antonetti, E.B. Wolpert, J.R. Connor, Neuroscience 121 (2003)
883–890.
[41] X.-G. Li, Y. Liao, M.-R. Huang, V. Strong, R.B. Kaner, Chem. Sci. 4 (2013) 1970–
1978.