Highly sensitive and selective turn-on fluorescent probes for Cu2+ based on rhodamine B

Article abstract of DOI:10.1039/c5tb00423c

A new rhodamine B-based fluorescent probe RL for Cu²⁺ has been designed, synthesized, and characterized. It exhibits a very high selectivity and sensitivity for the detection of Cu²⁺ in CH₃CN:H₂O = 1:9 (v/v) buffered with Britton-Robinson (pH = 7.02), the detection limit can reach 0.739 nM, which is the lowest reported. Furthermore, the probe RL can be made into test papers to detect the cupric ions in drinking water by the naked eye. RL can also be used for imaging Cu²⁺ in living cells and is almost non-toxic.

Full text of DOI:10.1039/c5tb00423c

View Article Online
View Journal
Journal of
Materials Chemistry B
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: Y. Yuan, S. Sun, S.
Liu, X. Song and X. Peng, J. Mater. Chem. B, 2015, DOI: 10.1039/C5TB00423C.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/materialsB

Page 1 of 5
Journal of Materials Chemistry B
View Article Online
DOI: 10.1039/C5TB00423C
Journal Name
RSCPublishing
ARTICLE
High sensitive and selective turn-on fluorescent probe
2
+
for Cu based on Rhodamine B
Cite this: DOI: 10.1039/x0xx00000x
∗
Ye Yuan , Shiguo Sun , Si Liu , Xinwei Song, Xiaojun Peng
2+
A new rhodamine Bꢀbased fluorescent probe RL for Cu has been designed, synthesized, and
characterized. It exhibits a very high selectivity and sensitivity for the detection of Cu in
Received 00th January 2012,
Accepted 00th January 2012
2+
CH CN
：H O = 1：9 (v/v) buffered with BrittonꢀRobinson (pH = 7.02), the detection limit can
2
3
DOI: 10.1039/x0xx00000x
reach 0.739 nM, which is the lowest reported. Furthermore, the probe RL can be made into test
papers to detect the cupric ions in drinking water by naked eyes. RL can also be used for imaging
www.rsc.org/
2
+
of Cu in living cells and is almost nonꢀtoxic.
Introduction
synthesized a novel pyreneꢀ and anthraceneꢀbased schiff base
derivatives as Cu and Fe fluorescence turnꢀon sensors with
2
+
3+
As the third most abundant essential trace element, Copper
plays an important role in biological process, because of its
redox reactivity, however, this could also do harm to the
1
ꢀ3
organisms.
Copper deficiency may lead to some serious
4
4
diseases, such as Alzheimer’s, Menkes’ and Wilson’s,
5
6
amyotrophic lateral sclerosis, and prion diseases. Thus,
developing a simple and rapid method to detect copper ions is
particularly important, which would make a contribution to the
understanding of these diseases aroused by copper ions.
In recent years, fluorescent chemosensors have been widely
used to detect metal ions owing to their high sensitivity, good
selectivity, short response time and realꢀtime monitoring etc.
One of the most commonly used dye model is rhodamine B,
because it has excellent photophysical properties, such as long
absorption and emission wavelengths extended to visible region,
high fluorescence quantum yield, and large extinction
Scheme 1. Synthesis and structures of the rhodamine B
derivative chemosensor RL
aggregation induced emissions. Kim and coworkers
7
coefficient etc. Many fluorescent chemosensors based on
rhodamine B and its derivatives have been developed for
32
synthesized a novel ratiometric and selective fluorescent sensor
2
+ 8ꢀ10
2+ 11,12
2+ 1,13ꢀ15
2+ 16,17
3+ 18,19
20
21ꢀ
Hg , Zn ,
Cu ,
Pd ,
Fe
, H2S , DNA
2+
33
for Cu based on two different approaches. Peng etc.
2
4
25
etc. For example, Dujols firstly used rhodamine B hydrazide
as a chemodosimeter for Cu detection. Kim and coworkers
synthesized a novel ratiometric and selective fluorescent sensor
for Cu based on two different approaches. Iyer developed a
highly selective probe to detect Cu and endogenous NO gas in
living cell. Lin etc. developed a FRETꢀBased ratiometric
fluorescent Cu
application for living cell imaging. Kumar synthesized a
highly selective fluorescence turnꢀon chemodosimeter based on
rhodamine for nanomolar detection of Cu . Peng etc.
synthesized a series of highly sensitive and selective fluorescent
and colorimetric “offꢀon” chemosensors for Cu (II) based on
2+
26
34
rhodamine derivatives. Tian
synthesized a hydrophilic
2
+
27
2+
copolymer as fluorescent film sensor for Cu
pyrophosphate anion. Goswami developed a new highly
selective, ratiometric and colorimetric fluorescence sensor for
and
2+
35
2
8
2
+
chemodosimeter, which had
a
good
2+
Cu with a remarkable red shift in absorption and emission
2
9
spectra based on internal charge transfer. Although significant
progress has been achieved in related field, further study is still
needed to design more efficient and practical sensors to monitor
2+
30
2+
synthesized a fluorescent ratiometric chemodosimeter for Cu
based on TBET with its application in living cells. Lin
2+
2+
Cu under different circumstance, for instance, the Cu
3
1
concentration in drinking water.
This journal is © The Royal Society of Chemistry 2013
J. Name., 2013, 00, 1-3 | 1

Journal of Materials Chemistry B
Page 2 of 5
View Article Online
ARTICLE
DOI: 10.1039/C 042
Jou5TrnB0al Na3Cme
Herein, we designed and synthesized a new rhodamine Bꢀ 128.57, 124.46, 123.27, 121.48, 113.26, 107.71, 98.00, 66.41,
2
+
+
based fluorescent probe RL (Scheme 1) for Cu detection, 44.39, 12.47. HRMS: [M+Na] , calcd: m/z = 633.2954, found:
which can be employed in CH CN H O = 1 9 (v/v) buffered m/z = 633.2941
：
：
3
2
with BrittonꢀRobinson (pH = 7.02), and the detection limit can
reach 0.739 nM, this is the lowest one reported till now. To Results and discussion
check its applicability, the probe RL was made into test papers Fluorescence response time of RL with Cu
2
+
to detect the cupric ions in drinking water; the detection limit Changes in the fluorescence intensity (I582 nm) of RL on
reaches 10 M (0.64 mg/L) by naked eyes, which is lower than treatment with CuCl were monitored over time in Figure 1. It
the permissible Cu concentration in drinking water that the can be observed that the fluorescence intensity increased
ꢀ
2
2+
2
+
World Health Organization had claimed (1 mg/L). So the probe rapidly after the addition of Cu , and reached a maximum in
can be employed to detect the cupric ions in drinking water. 10 min. Therefore, all the subsequent fluorescent measurements
2+
Furthermore, RL can work pretty well for imaging of Cu in were carried out after allowing for a 10 min equilibration time.
living cells and is almost nonꢀtoxic.
Experimental
900
00
700
8
Materials and Apparatus
All reagents and solvents were purchased from commercial
sources, and the solvents used were of analytical grade. Doubly
purified water used in all experiments was from MilliꢀQ
systems. The RL stock solution was prepared at a concentration
of 1.0 × 10 M in 10 mL DMSO, and the stock solution was
diluted to a desired concentration for each titration in a 3 mL
600
500
400
300
200
100
0
−
3
cuvette using CH CN
： H O = 1 ： 9 (v/v) buffered with
2
3
BrittonꢀRobinson, pH = 7.02. Each inorganic metal salt and
-100
anions stock solutions were prepared at the concentration of
-
2
0
2
4
6
8
10 12 14 16
1
2
5.0 mM, the concentration of CuCl is 5.0 mM. The H NMR
2
1
3
Time(min)
and C NMR spectra were recorded on a VARIAN INOVAꢀ
00 spectrometer. Mass spectrometric data were obtained at Qꢀ
4
Figure 1. Timeꢀdependent fluorescent intensities (I582 nm)
change of RL (10 M) with CuCl (10 M) in CH CN H O =
:9 (v/v) buffered with BrittonꢀRobinson, pH = 7.02, λex = 540
nm
Tof MS spectrometer (Micromass, Manchester, England).
Fluorescence spectra were obtained by Agilent Cary Eclipse
fluorescence spectrophotometer. Absorption spectra were
obtained by Agilent 8453 UVꢀVisible spectrophotometer. The
pH values were measured with a Model pHSꢀ3C pH meter
ꢀ
ꢀ
：
2
2
3
1
Fluorescence and UV-vis Spectra Titration of RL
The change in fluorescence and absorption spectra of RL upon
(
Shanghai, China). Fluorescence imaging was performed using
an OLYMPUS FVꢀ1000 inverted fluorescence microscope with
a 60×objective lens.
titration with CuCl are displayed in Figure 2. In the presence
2
of CuCl , RL (10 ꢀM) in the CH CN/H O (1:9, v/v) buffered
3 2
2
with BrittonꢀRobinson (pH = 7.02) displayed a fluorescence
Synthetic procedures
Synthesis of R1
R1 was synthesized according to the literature.
peak at 582 nm. With continuous addition of CuCl , the
2
absorption maximum changed from 575 nm to 550 nm and the
absorbance value increased from 0 to 0.46, together with an
obvious color change to pink. According to the result of
titration experiment (Figure 3), the detection limit was 0.739
2
5
Synthesis of RL
R1 (0.5 g, 1.00 mmol) was dissolved in 35 mL 2ꢀpropanol in a
00 mL flask, then 2.33 g (10.0 mmol) 6ꢀbromoꢀ2,2'ꢀbipyridine
1
26
nM, which was the lowest that had been ever reported.
was added to the flask under vigorous stirring. The reaction
mixture was heated to 65 ºC for 3 h, then the reaction was
cooled to room temperature and washed with saturated
Fluorescence properties
The high selectivity of RL for Cu was further evaluated by the
fluorescent spectra. As shown in Figure 4, no fluorescence can
2+
NaHCO , the concentrated crude compound was purified by
3
column chromatography on silica gel (60:1 dichloromethane :
2+
3+
+
2+
be observed when 10 equiv. metal ions of Pb , Fe , Ag , Ca ,
1
methanol v/v) to afford a pink solid (520 mg, 79 %). H NMR
2+
+
2+
+
3+
2+
2+
3+
2+
2+
2+
Cd , K , Co , Na , Cr , Fe , Hg , Al , Mn , Ni , Zn
(
400 MHz, CDCl3)
Hz, 1H), 8.09 – 7.96 (m, 1H), 7.78 – 7.51 (m, 4H), 7.32 (t,
.9 Hz, 1H), 7.24ꢀ7.19 (m, 1H), 6.54 (d, = 9.2 Hz, 2H), 6.30
d, = 8.1 Hz, 4H), 6.14 (s, 1H), 3.30 (q, = 7.0 Hz, 8H), 1.13
t, = 7.0 Hz, 12H). C NMR (100 MHz, CDCl3) 166.57,
δ
8.59 (d,
J
= 4.6 Hz, 1H), 8.19 (d,
J
= 8.0
2+
were added and measured 10 minutes later, only Cu ions
induced a large increase in fluorescence intensity of RL.
J
=
7
(
(
J
J
J
J
1
3
δ
1
58.31, 153.88, 150.38, 148.79, 138.05, 136.57, 133.24, 130.41,
2
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 3 of 5
Journal Name
Journal of Materials Chemistry B
View Article Online
ART23ICLE
DOI: 10.1039/C5TB004 C
intensity when compared with that obtained in the absence of
any interference ions, and not any obvious reducing of the
5
4
4
3
3
2
2
1
1
00
50
00
50
00
50
00
50
00
0
.5
0.4
0.3
2+
2+
2ꢀ
fluorescence intensity was observed except Pb
、Hg 、SO3
2+
ions. This suggested the probe can be used to detect Cu ions
in complex environment.
0.2
0.1
0.0
5
0
0
Effect of pH
-
0.1
560
580
600
620
640
450
500
550
600
650
The spirolactone ring of the rhodamine moiety in RL is
susceptible to change with different pH; typically at acidic pH,
the ring opens, making the nonꢀfluorescent rhodamine moiety
emit red fluorescence. Such a behavior can interfere with the
Wavelength (nm)
Wavelength (nm)
Figure 2. The fluorescence and absorption (λ =540 nm)
ex
spectra of RL (10
ꢀM) along with the addition of CuCl (0– 40
2
M) in CH CN/H O (1:9, v/v) buffered with BrittonꢀRobinson,
at room temperature. pH = 7.02. All spectra were recorded
2+
ꢀ
3
2
detection of Cu
fluorescence properties of RL in solutions with di
ions. Therefore, we evaluated the
erent pH
ff
1
0min after the addition of CuCl2.
values (2.66–7.02, Figure 7). The fluorescence intensity
remained stable in the pH range 5.3ꢀ7.0, but it increased as the
1
00
9
00
800
00
600
Y
= 3.06468 + 11.01605X
8
6
4
2
0
0
0
0
0
7
2
R =0.9919
500
400
300
200
100
0
0
2
4
6
8
2
+
Cu ( uM)
Figure 3. Fluorescent intensities change of RL (10
ꢀ
ꢀ
M) in the Figure 5. Fluorescence intensity of RL (10
M).
of CuCl (30 M) in the presence of other metal ions (100
in CH CN/H O (1:9, v/v) buffered with BrittonꢀRobinson, pH =
ꢀ
M) after addition
presence of different concentrations of CuCl (0 – 8
2
ꢀ
ꢀ
M)
2
3
2
7
.02. λex = 540 nm.
1
000
1000
900
9
8
7
6
5
4
3
2
1
00
00
00
00
00
00
00
00
00
0
2+
Cu
800
700
600
500
400
300
200
100
0
Other ions
600
560
580
620
640
Wavelength (nm)
Figure 6. Fluorescence intensity of RL (10
of CuCl (30 M) in the presence of other common anions (100
M) in CH CN/H O (1:9, v/v) buffered with BrittonꢀRobinson,
ꢀM) after addition
Figure 4. Fluorescence intensity of RL (10
ꢀ
M) in the presence
ꢀ
2
+
2
of di
fferent metal ions (30 ꢀM for Cu ions and 100 ꢀM for
ꢀ
3
2
other metals ions) in CH CN/H O (1:9, v/v) buffered with
3
2
pH = 7.02. λex = 540 nm.
BrittonꢀRobinson, pH = 7.02. λex = 540 nm.
pH values decreased from 5.3 to 2.66, which was attributed to
the opening of the spirolactone ring. The analysis of the pH
curve determined the pKa of RL to be 3.70.
To investigate the influence of the different metal ions,
2+
interference experiments (determining Cu ions in the presence
of other ions) were also performed (Figure 5, Figure 6). Most of
the metal ions caused only little variations in the fluorescence
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 3

Journal of Materials Chemistry B
Page 4 of 5
View Article Online
ARTICLE
DOI: 10.1039/C 042
Jou5TrnB0al Na3Cme
Scheme 2. The Proposed Determination Mechanism
Fast detection of Cu in filter papers
70
60
50
40
30
20
10
0
2+
Filter papers were immersed in a dichloromethane solution of
RL (1 mM) and then dried in the air to prepare test strips. After
immersing them in the cupric ion aqueous solution for several
seconds and drying in the air, the test strips exhibited a rapid
pKa=3.70
2+
color change with the increase of the Cu concentration, which
can be observed by naked eyes. From the filter papers in Figure
8
, we can see the color change ranged from colorless to purple,
and the detection limit reaches 10 M (0.64 mg/L), this also is
the lowest detection limit that reported in practical application
ꢀ
2
.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
pH
2
+
and is lower than the permissible Cu concentration in drinking
Figure 7. Plot depicting the pH (2.66–7.02)ꢀdependent water that the World Health Organization had claimed (1 mg/L).
variation in the fluorescence intensity of RL (10
Robinson buffer solution. λex = 540 nm.
ꢀ
M) in Brittonꢀ Thus, the test papers of probe RL can be used to monitor the
cupric ions in drinking water.
Reaction mechanism
From Figure S2 we can see that the reaction between probe RL
2
+
and Cu is irreversible, so it may be a chemical change, this
fluorescence enhancement response of chemosensor RL in the
2+
presence of Cu is most likely the result of ionꢀcatalyzed
hydrolysis reaction, which can be observed in the Mass Spectra
(
6
Figure S4), the molecular ion peak of RL changes rapidly from
2+
11.43 to 457.33 in the presence of Cu . We did a reaction of
2
+
Cu and RL, 5 min later, TLC was employed to check the
status. As shown in Figure S5(a), a new point of RLꢀCu was Figure 8. Color changes of paper test strips for detecting cupric
observed, which exhibited the same R as R1 , and the reactant ions in aqueous solution with different cupric ion
f
−6
−5
concentrations. Left to right: 0, 1.0×10 M, 1.0×10 M,
RL was still existed, this means that the hydrolysis occurred
under the catalysis of Cu(II). And about 12 min later, we did
the TLC experiment again, as shown in Figure S5(b), only the
new point RLꢀCu can be observed, and both R1 and RLꢀCu are
in the fluorescent ring opening form on the acidic silica gel
−
4
−3
1
.0×10 M, 1.0×10 M.
Cell imaging
To further check the practical applicability of probe RL in
biological samples, fluorescence imaging experiments were
carried out in living MCFꢀ7 cells (Figure 9). In the absence of
Cu , RL showed no detectable fluorescence signal in living
cells. After incubation with Cu , a bright fluorescence was
1
plate. The product of RLꢀCu was collected and H NMR
spectra were measured in both CDCl (Figure S6) and DMSOꢀ
3
2+
d6 (Figure S7), not much difference can be observed compared
with that of R1. Meanwhile, HRMS (Figure S8) can provide
some further evidence. All these demonstrated that the
hydrolysis product of RLꢀCu is the ringing opening form of
R1,and two Cu ions are coordinated with one RL molecule,
which could be supported by the results of the Jobꢀplot (Figure
S1).The hydrolysis mechanism can be proposed as follows:
2+
observed in living cells, and the MTT experiments (Figure S3)
indicate that probe RL is almost nonꢀtoxic. The results suggest
2
+
that probe RL can be used for imaging of Cu in living cells.
2+
Dark Field
Bright Field
Merge
Et
2
N
O
NEt
2
Et
2
N
O
NEt
2
Cu2+
Cu2+
Cl
N
NH
N
NH
N
N
O
N
O
Cu2+
N
RL
Et
2
N
O
NEt
2
H O
2
H
N
NH
2
O
Figure 9. Fluorescence imaging of RL (10
in the absence (a) and presence (d) of Cu ion (50 ꢀM). λex =
ꢀ
M) in MCFꢀ7 cells
RL-Cu
2+
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 5 of 5
Journal Name
Journal of Materials Chemistry B
View Article Online
ART23ICLE
DOI: 10.1039/C5TB004 C
5
15 nm.
11 Z. C. Xu, J. Y. Yoon and D. R. Spring, Chem. Soc. Rev., 2010, 39,
Conclusion
1996.
1
2
3
K. Sreenath, R. J. Clark and L. J. Zhu, Org. Chem., 2012, 77, 8268.
In summary, a highly selective and sensitive fluorescent probe
1
F. J. Huo, C. X. Yin, Y. T.Yang, J. Su, J. B. Chao and D. S. Liu,
Anal. Chem., 2012, 84, 2219.
2+
RL for Cu ions was synthesized and characterized. The probe
2+
RL exhibited colorimetric responses to Cu ions, providing a
1
4
C. W. Yu, J. Zhang, R. Wang and L. X. Chen, Org. Biomol. Chem.,
2
+
method for visual detection of Cu ions. This probe can work
in CH CN H O = 1 9 (v/v) buffered with BrittonꢀRobinson
pH = 7.02) with a detection limit of 0.739 nM, which is the
2010, 8, 5277.
：
：
3
2
15 C. W. Yu, L. X. Chen, J. Zhang, J. H. Li, P. Liu, W. H. Wang, B.
(
Yan, Talanta, 2011, 85, 1627.
lowest ever reported till now. The probe RL can be made into
test papers to detect the cupric ions in drinking water with the
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
6
S. G. Sun, B. Qiao, N. Jiang, J. T. Wang, S. Zhang and X. J.Peng,
Org. Lett., 2014, 16, 1132.
real detection limit of 10 ꢀM (0.64 mg/L), which is lower than
7
B. Qiao, S. G. Sun, N. Jiang, S. Zhang and X. J. Peng, Dalton
Trans., 2014, 43, 4626.
2+
the permissible Cu concentration in drinking water that the
World Health Organization had claimed (1 mg/L). Furthermore,
8 M. M.Chai, D. Zhang, M. Wang, H. J. Hong, Y. Ye and Y. F. Zhao,
Sensor Actuat B ꢁ Chem., 2012, 174, 231.
2
+
the probe RL can be used for imaging of Cu in living cells and
is almost nonꢀtoxic.
9 Y. J. Ding, H. Zhu, X. X. Zhang, J. J. Zhu and C. Burda, Chem.
Commun., 2013, 49, 7797.
0
F. B. Yu, X. Y. Han and L. X. Chen, Chem. Commun., 2014, 50
,
12234.
1 C. H. Leung, D. S. H. Chan, H. Z. He, Z. Cheng, H. Yang and D. L.
Ma, Nucleic Acids Res., 2012, 40, 941.
Acknowledgement
2 H. Z. He, K. H. Leung, W. Wang, D. S. H., Chan, C. H. Leung and
D. L. Ma, Chem. Commun., 2014, 50, 5313.
This work was financially supported by the National Natural Science
Foundation of China (Nos. 21272030, 21472016, 21421005).
3
H. Z. He, D. S. H. Chan, C. H. Leung and D. L. Ma, Nucleic Acids
Res., 2013, 41 4345.
4 L. Lu, D. S. H. Chan, D. W. Kwong, H. Z. He, C. H. Leung and D.
L. Ma, Chem. Sci., 2014, , 4561.
5 V. Dujols, F. Ford and A. W. Czarnik, J. Am. Chem. Soc., 1997,
19, 7386.
,
Notes and references
5
State Key Laboratory of Fine Chemicals, Dalian University of
Technology, E224 West Campus, No. 2, Linggonglu, 116024, Dalian,
China. Eꢀmail: shiguo@dlut.edu.cn.
1
6
J. F. Zhang, Y. Zhou, T. Y. Yoon, Y. Kim, S. J. Kim, J. S. Kim,
1
13
Org. Lett., 2010, 12, 3852.
Electronic Supplementary Information (ESI) available: H NMR,
C
7 B. Muthuraj, R. Deshmukh, V. Trivedi and P. K. Iyer, Appl. Mater.
Interfaces., 2014, , 6562.
L. Yuan, W.Y. Lin, B. Chen and Y. N. Xie, Org. Lett., 2010, 14
32.
NMR, and MS. See DOI: 10.1039/b000000x/
6
8
9
0
1
2
3
,
1
2
M. Kumar, N. Kumar, V. Bhalla, P. R. Sharma and T. Kaur, Org.
4
Lett., 2012, 14, 406.
M. Kumar, N. Kumar, V. Bhalla, P. R. Sharma and T. Kaur, Org.
Lett., 2012, 14, 406.
S. C. Leary, D. R.Winge and P. A. Cobine, Biochim. Biophys. Acta,
Mol. Cell Res., 2009, 1793, 146.
J. L. Fan, P. Zhan, M. M. Hu, W. Sun, J. Z. Tang, J. Y. Wang, S.
G.Sun, F. L. Song and X. J. Peng, Org. Lett., 2013, 15, 492.
M. Shellaiah, Y. H.Wu, A. Singh, M. V. R. Raju and H. C. Lin, J.
3
4
M. L. Turski and D. J. Thiele, J. Biol. Chem., 2009, 284, 717.
K. J. Barnham, C. L. Masters and A. I. Bush, Nat. Rev. Drug
Discovery., 2004,
D. J. Waggoner , T. B. Bartnikas and J. D. Gitlin, Neurobiol. D.
999, , 221; J. S. Valentine, P. A. Doucette and S. Z. Potter,
Annu. Rev. Biochem., 2005, 74, 563.
3, 205.
Mater. Chem. A., 2013, 1, 1310.
5
6
,
J. F. Zhang, Y. Zhou, T. Y. Yoon, Y. Kim, S. J. Kim, J. S. Kim,
Org. Lett., 2010, 12, 3852.
1
6
M. Dong, T. H. Ma, A. J. Zhang, Y. M. Dong, Y. W. Wang and Y.
Peng, Dyes Pigm., 2010, 87, 164.
L. I. Bruijn, T. M. Miller and D. W. Cleveland, Annu. Rev.
Neurosci., 2004, 27, 723; D. R. Brown and H. Kozlowski, Dalton
3
4 Z. Q. Guo, W. H. Zhu and H.Tian, Macromolecules., 2010, 43,739.
5 S. Goswami, D. Sen and N. K. Das, Org. Lett., 2010, 12, 856.
Trans., 2004, 7, 1907.
3
7
8
9
0
J. R. Lakowicz, Principles of Fluorescence Spectroscopy, 3rd ed.;
Springer: New York. 2006; pp 67.
Y. J . Gong, X. B. Zhang, C. C. Zhang, A. L. Luo, T. Fu, W. H.
Tan, G. L. Shen and R. Q. Yu, Anal. Chem., 2012, 84, 10777.
K. Bera, A. K. Das, M. Nag and S. Basak, Anal. Chem., 2014, 86
740.
,
2
1
S. Saha, P. Mahato, U. Reddy, G. E. Suresh, A. Chakrabarty, M.
Baidya, S. K. Ghosh and A. Das, Inorg. Chem., 2012, 51, 336.
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 5