Visual and colorimetric detection of cyanide anion based on a "turn-off" daylight fluorescent molecule

Article abstract of DOI:10.1246/cl.2011.623

A strong daylight-fluorescent boron dipyrromethene (BODIPY) derivative 1 has been synthesized for the visual and colorimetric detection of cyanide anion in solution. BODIPY 1 shows a glow characteristic of daylight-fluorescent material since emitted fluor

Full text of DOI:10.1246/cl.2011.623

doi:10.1246/cl.2011.623
Published on the web May 21, 2011
623
Visual and Colorimetric Detection of Cyanide Anion Based
on a “Turn-off” Daylight Fluorescent Molecule
Lijuan Jiao,*1,2 Mingming Liu,1,2 Min Zhang,1,2 Changjiang Yu,1,2 Zhaoyun Wang,1,2 and Erhong Hao1,2
1Anhui Key Laboratory of Functional Molecular Solids, College of Chemistry and Material Science,
Anhui Normal University, Wuhu 241000, P. R. China
2Anhui Key Laboratory of Molecular Based Materials, College of Chemistry and Material Science,
Anhui Normal University, Wuhu 241000, P. R. China
(Received March 15, 2011; CL-110222; E-mail: jiao421@mail.ahnu.edu.cn)
A
strong daylight-fluorescent boron dipyrromethene
cyanide, and possibly other nucleophiles, could attack the ¡-
position of the dicyanovinyl group to generate stabilized anionic
species, resulting in the reduced extent of conjugation and a
spectral change. In comparison to the parent ¢-unsubstituted
BODIPY 3, the increased conjugation in BODIPY 1 leads to the
red shift of both the absorption and emission spectra. Thus,
nucleophilic addition of anions to the ¡-position of the vinyl
group would be expected to produce a color change or at least in
perceived brightness or intensity. BODIPY 1 would act as a
cyanide-selective colorimetric sensor in the case that cyanide
anion was the only nucleophile capable of inducing such changes.
The anion sensing property of BODIPY 1 was studied in a
98% CH3CN (CH3CN/water 98/2 (v/v)) solution. The anions
(BODIPY) derivative 1 has been synthesized for the visual
and colorimetric detection of cyanide anion in solution.
BODIPY 1 shows a glow characteristic of daylight-fluorescent
material since emitted fluorescent light has been added to the
simple reflection light under daylight illumination. This green
daylight fluorescence is diminished upon interaction with
cyanide anion, resulting in a highly selective and sensitive
naked-eye detection of cyanide anion over other common
anions.
The extreme toxicity of cyanide and the environmental
concerns from its continued industrial use have lead to the
growing interest in the development of facile and sensitive
methods for cyanide detection.1-3 A number of cyanide sensors
and indicators have been developed4-6 based on the coordination
ability4e,5 and nucleophilic reactivity6 of cyanide anion. Among
those, colorimetric chemosensors are of particular interest due to
simplicity, allowing naked-eye detection without resorting to
any spectroscopic instrumentation.7 For instance, Sessler5b,6a,7e
and Akkaya7f have developed colorimetric chemosensors for
cyanide anion based on the benzil and boradiazaindacene
(BODIPY) platform. Kawashima reported a fluorescence color
change of boron-substituted diarylazomethine by reaction with
cyanide.7j,7k However, there remains a need for carefully
designed colorimetric chemosensors for the selective, sensitive,
and straightforward signaling of the presence of cyanide anion.
BODIPY dyes have excellent photophysical properties, and
the recent developments8 in new synthetic strategies for their
functionalizations have lead to wide research interests in a highly
diverse fields9 as fluorescent organic devices,10 energy-transfer
cassettes,11 light-harvesting systems,12 potential sensitizers for
photodynamic therapy,13 and ion sensing and signaling re-
agents.14,15 Herein, we report a new BODIPY-based optical
sensor 1 (Scheme 1) for the naked-eye detection of cyanide anion.
In our sensor design, a dicyanovinyl group, as a putative
cyanide-dependent reactive subunit, has been installed onto a
BODIPY platform through a simple Knoevenagel condensation
on the ¢-formyl BODIPY 2.8i The structure of BODIPY 1 was
¹
¹
¹
¹
¹
¹
selected for this study were SCN , Br , Cl , F , I , NO3
,
¹
¹
¹
CH3CO2 , H2PO4 , and CN . When a solution of BODIPY 1
(10 ¯M) was treated with a fixed amount of selected anions (20
¹
equiv of CN and 50 equiv of other anions), only the addition of
¹
CN caused a significant change in the absorption and emission
spectra as shown in Figure 1. The decrease of absorption
intensity and a blue shift of absorption band from 508 to 500 nm
were observed for BODIPY 1 (Figure 1a). Similarly, the
quenching of more than 90% of the fluorescence emission was
¹
observed for BODIPY 1 with the addition of CN , with a blue
shift of the emission band from 539 to 514 nm (Figure 1b).
Time-dependent UV-vis (Figure S1 in Supporting Information;
SI16) and fluorescent studies (Figure S2 in SI16) indicated the
reaction is finished at 20 min at room temperature.
¹
To confirm the good selectivity of BODIPY 1 to CN over
¹
the other selected anions, competition experiments between CN
and these anions were performed in a 98% CH3CN (CH3CN/
water 98/2 (v/v)) solution, and the results are summarized in
Figure 2 and Figure S3.16 When 50 equiv of these selected
anions was added into solution of BODIPY 1 containing 20
600
400
200
0
0.6
0.4
0.2
0.0
(a)
(b)
Others
Others
CN-
CN-
confirmed by H NMR, 13C NMR, and MS. It was expected that
1
400
500
600
700
500
550
600
650
Wavelength/nm
Wavelength/nm
Figure 1. (a) UV-vis (1.0 © 10¹5 M) and (b) fluorescence (1.0 ©
10¹6 M, excited at 470 nm) spectra of BODIPY 1 in 98% CH3CN
(CH3CN/water 98/2 (v/v)) in the presence of 20 equiv of NaCN or
¹
¹
¹
¹
¹
¹
50 equiv of other anions (including SCN , Br , Cl , F , I , NO3
CH3CO2 , and H2PO4 ).
,
¹
¹
Scheme 1. Synthesis of the optical chemsensor 1.
Chem. Lett. 2011, 40, 623-625
© 2011 The Chemical Society of Japan
www.csj.jp/journals/chem-lett/

624
Blank
(a)
(b)
0.45
450
300
150
0
CN- + Others
Blank
0.30
0.15
0.00
CN-
CN-
-
CN + Others
400
500
600
700
500
550
600
650
Wavelength/nm
Wavelength/nm
Figure 2. (a) UV-vis (1.0 © 10¹5 M) and (b) fluorescence (1.0 ©
10¹6 M, excitation at 470 nm) spectra of BODIPY 1 in 98% CH3CN
(CH3CN/water 98/2 (v/v)). Black line, in the absence of anions
(blank); red line, in the presence of 20 equiv of NaCN; blue line, in
Figure 4. Photograph of different concentrations of BODIPY 1 in
98% CH3CN (CH3CN/water 98/2 (v/v)) solutions in the absence
(a, c, e, and g) and presence (b, d, f, and h) of 20 equiv of CN
¹
the presence of 20 equiv of CN and 50 equiv of other anions
¹
¹
¹
¹
¹
¹
¹
¹
(including SCN , Br , Cl , F , I , NO3 , CH3CO2 , and H2PO4 ).
¹
under ambient light (top), and a 360 nm hand-held UV light
600
¹4
(bottom). Concentrations for BODIPY 1 from left to right: 1 © 10
(a)
(b)
0.04
0.02
0.75
0.50
0.25
0.00
¹5
¹5
(a and b), 5 © 10 (c and d), 1 © 10 (e and f), and 5 © 10¹6 M
400
(g and h).
0.00 0.25 0.50 0.75 1.00
1/[CN-]
200
0
300
400
500
600
700
500
550
600
650
Wavelength/nm
Wavelength/nm
Figure 3. (a) UV-vis spectral changes of BODIPY 1 (1.0 ©
10¹5 M) in 98% CH3CN (CH3CN/water 98/2 (v/v)) in response to
increasing concentration of NaCN (0-1.4 © 10¹4 M). The spectra
were recorded 20 min after addition of NaCN. (b) Fluorescence
spectral changes of BODIPY 1 (1.0 © 10¹6 M) in 98% CH3CN
(CH3CN/water 98/2 (v/v)) in response to increasing concentration
of NaCN (0-2.0 © 10¹5 M). Excitation was set at 470 nm, with slit
widths of 5 nm. Insert: Plot of fluorescence intensity at 539 nm vs.
¹
number of equiv of CN .
Figure 5. The proposed detection mechanism for BODIPY 1 (a)
1
and the H NMR spectra of BODIPY 1 (4 mM) in the absence (b)
¹
equiv of CN , both the absorption and emission spectra
and in the presence (c) of cyanide anion (80.0 mM) in CD3CN at
25 °C. 1H NMR spectra of BODIPY 1 was recorded 10 min after the
addition of NaCN.
¹
displayed similar patterns to those with CN alone. Thus,
BODIPY 1 showed excellent selectivity for CN over the other
¹
selected anions.
¹
Once the selectivity of BODIPY 1 for CN was established,
of a reddish-brown nonfluorescent solution. As expected, in 98%
CH3CN solution (CH3CN/water 98/2 (v/v)), quantum yields
¹
we further studied its sensitivity toward CN . Titration of
BODIPY 1 in 98% CH3CN solution (1.0 © 10¹5 M; CH3CN/
for BODIPY 1 and the 1-CN complex are calculated to be 0.46
¹
¹
water 98/2 (v/v)) with CN showed a progressive blue shift of
and 0.01, respectively, by using fluorescein as reference (0.95 in
0.1 M NaOH solution). Consistent with the interesting color
changes, under 360-nm hand-held UV light excitation, BODIPY
the absorption band from 508 to 500 nm (Figure 3a), with two
isosbestic points at 468 and 530 nm indicating an interconver-
sion into single discrete chemical species during the titration.
The corresponding fluorescence spectral changes of BODIPY 1
¹
1 showed a strong green fluorescence in the absence of CN
despite its weak absorption at this wavelength, while a complete
¹
¹
on addition of increasing concentration of CN are shown in
shutdown of the fluorescence was observed for 1-CN complex.
¹
Figure 3b. The gradual decrease of fluorescence and a blue shift
of the emission band from 539 to 514 nm were observed. It only
This naked-eye inspection of CN can be performed by using
BODIPY 1 at a concentration as low as 5 © 10¹6 M. Unlike
most of the colorimetric sensors that generally rely on a larger
shift of the spectra, our naked-eye detection of cyanide anion is
based on a “turn-off” daylight-fluorescent molecule to achieve
the sensitive and straightforward sensing of cyanide anions, in
which a strong daylight-fluorescent molecule and a subsequent
dramatic “turn-off” of this daylight fluorescence upon inter-
action with target anions are required.
¹
required 10 ¯M of CN to quench more than 90% of the
fluorescence of BODIPY 1. The detection limit17 of BODIPY 1
for CN is about 3.0 © 10¹6 M (Figure S4 in SI).16
¹
¹
The sensitive sensing ability of BODIPY 1 toward CN was
also evident by naked-eye inspection as shown in Figure 4: a
color change from green to reddish brown (concentrated) or pink
(diluted) solution of BODIPY 1 was observed upon addition of
¹
1
CN under ambient light. In contrast to ordinary color changes
The H NMR spectral changes (Figure 5 and Figure S5 in
that cyanide anion induced, the dramatic color change observed
here is due to the strong green daylight fluorescence of the
BODIPY 1 and a dramatic quenching of this daylight fluores-
cence upon addition of cyanide anion resulting in the formation
SI16) of BODIPY 1 upon addition of cyanide anion confirmed
that it is an irreversible Michael-addition-based response
mechanism for cyanide detection as shown in Figure 5a. Upon
addition of 20 equiv of cyanide anion to BODIPY 1 in CD3CN
Chem. Lett. 2011, 40, 623-625
© 2011 The Chemical Society of Japan
www.csj.jp/journals/chem-lett/

625
Li, ACS Appl. Mater. Interfaces 2009, 1, 2529. e) J. L. Sessler, D.-G.
Cho, Org. Lett. 2008, 10, 73. f) Z. Ekmekci, M. D. Yilmaz, E. U.
Akkaya, Org. Lett. 2008, 10, 461. g) H.-T. Niu, D. Su, X. Jiang, W.
Yang, Z. Yin, J. He, J.-P. Cheng, Org. Biomol. Chem. 2008, 6, 3038. h)
Y.-K. Yang, J. Tae, Org. Lett. 2006, 8, 5721. i) K.-S. Lee, J. T. Lee, J.-I.
Hong, H.-J. Kim, Chem. Lett. 2007, 36, 816. j) J. Yoshino, N. Kano, T.
Kawashima, Bull. Chem. Soc. Jpn. 2010, 83, 1185. k) J. Yoshino, N.
Kano, T. Kawashima, J. Org. Chem. 2009, 74, 7496.
Some recent examples: a) V. Leen, V. Z. Gonzalvo, W. M.
Deborggraeve, N. Boens, W. Dehaen, Chem. Commun. 2010, 46,
4908. b) V. Leen, E. Braeken, K. Luckermans, C. Jackers, M.
Van der Auweraer, N. Boens, W. Dehaen, Chem. Commun. 2009,
4515. c) O. Buyukcakir, O. A. Bozdemir, S. Kolemen, S. Erbas, E. U.
Akkaya, Org. Lett. 2009, 11, 4644. d) J. Han, O. Gonzalez, A. Aguilar-
Aguilar, E. Peña-Cabrera, K. Burgess, Org. Biomol. Chem. 2009, 7, 34.
e) L. Wu, K. Burgess, Chem. Commun. 2008, 4933. f) E. Lager, J. Liu,
A. Aguilar-Aguilar, B. Z. Tang, E. Peña-Cabrera, J. Org. Chem. 2009,
74, 2053. g) L. Jiao, C. Yu, T. Uppal, M. Liu, Y. Li, Y. Zhou, E. Hao,
X. Hu, M. G. H. Vicente, Org. Biomol. Chem. 2010, 8, 2517. h) L.
Jiao, C. Yu, M. Liu, Y. Wu, K. Cong, T. Meng, Y. Wang, E. Hao,
J. Org. Chem. 2010, 75, 6035. i) L. Jiao, C. Yu, J. Li, Z. Wang, M. Wu,
E. Hao, J. Org. Chem. 2009, 74, 7525. j) A. Wakamiya, N. Sugita, S.
Yamaguchi, Chem. Lett. 2008, 37, 1094.
at room temperature, the complete disappearance of vinylic
proton (Ha) at 7.98 ppm, the appearance of a new peak (Hb) at
4.40 ppm, and a slight upfield shift of ¢-pyrrolic proton (Hc)
from 6.32 to 6.11 ppm were observed (Figures 5b and 5c). These
observations clearly show that the cyanide anion is added to the
vinyl group as expected and leads to the disruption in the
extended ³ conjugation of BODIPY 1. This explains the
observed optical spectral changes for the BODIPY 1 solution on
contact with cyanide anion. Interestingly, the absence of the
signal corresponding to the ¢-proton of the malononitrile group
in the 1H NMR spectrum was observed, which may be attributed
to the formation of the stabilized anionic species upon
nucleophilic addition of cyanide anion.4a The resulting anionic
species may be responsible for the dramatic fluorescence
quenching through intramolecular photoinduced electron trans-
fer to BODIPY core.18
8
In summary, we have designed a new visible and colori-
metric sensor for the selective and sensitive sensing of cyanide
ions based on a strong daylight-fluorescent BODIPY dye. The
sensing mechanism has been investigated by UV-vis absorption,
emission, and NMR spectroscopy. Cyanide anion has been
added to the vinyl group of BODIPY 1 to cause the disruption of
the extended ³ conjugation and a dramatic quenching of this
daylight green fluorescence. The dramatic color change clearly
visible to the naked eye may be attributed to the strong green
daylight fluorescence of BODIPY 1 and the subsequent
formation of a reddish-brown nonfluorescent solution upon
addition of cyanide anion because of the dramatic decrease of
9
a) A. Loudet, K. Burgess, Chem. Rev. 2007, 107, 4891. b) G. Ulrich, R.
Ziessel, A. Harriman, Angew. Chem., Int. Ed. 2008, 47, 1184. c) R.
Ziessel, G. Ulrich, A. Harriman, New J. Chem. 2007, 31, 496.
10 G. Ulrich, C. Goze, M. Guardigli, A. Roda, R. Ziessel, Angew. Chem.,
Int. Ed. 2005, 44, 3694.
11 Some recent examples: a) A. C. Benniston, G. Copley, A. Harriman, D.
Howgego, R. W. Harrington, W. Clegg, J. Org. Chem. 2010, 75, 2018.
b) O. A. Bozdemir, Y. Cakmak, F. Sozmen, T. Ozdemir, A.
Siemiarczuk, E. U. Akkaya, Chem.®Eur. J. 2010, 16, 6346. c) S.
Diring, F. Puntoriero, F. Nastasi, S. Campagna, R. Ziessel, J. Am.
Chem. Soc. 2009, 131, 6108. d) Y. Kataoka, Y. Shibata, H. Tamiaki,
Chem. Lett. 2010, 39, 953.
¹
the fluorescent quantum yield in 1-CN complex.
12 a) R. Ziessel, A. Harriman, Chem. Commun. 2011, 47, 611. b) M.
Yuan, X. Yin, H. Zheng, C. Ouyang, Z. Zuo, H. Liu, Y. Li, Chem.®
Asian J. 2009, 4, 707. c) S. Zrig, P. Rémy, B. Andrioletti, E. Rose, I.
Asselberghs, K. Clays, J. Org. Chem. 2008, 73, 1563. d) S. Erten-Ela,
M. D. Yilmaz, B. Icli, Y. Dede, S. Icli, E. U. Akkaya, Org. Lett. 2008,
10, 3299. e) X. Zhang, Y. Xiao, X. Qian, Org. Lett. 2008, 10, 29.
13 a) S. H. Lim, C. Thivierge, P. Nowak-Sliwinska, J. Han, H. Bergh, G.
Wagnieres, K. Burgess, H. B. Lee, J. Med. Chem. 2010, 53, 2865. b) S.
Atilgan, Z. Ekmekci, A. L. Dogan, D. Guc, E. U. Akkaya, Chem.
Commun. 2006, 4398. c) T. Yogo, Y. Urano, Y. Ishitsuka, F. Maniwa,
T. Nagano, J. Am. Chem. Soc. 2005, 127, 12162. d) A. Gorman, J.
Killoran, C. O’Shea, T. Kenna, W. M. Gallagher, D. F. O’Shea, J. Am.
Chem. Soc. 2004, 126, 10619.
14 Recent examples: a) O. A. Bozdemir, R. Guliyev, O. Buyukcakir, S.
Selcuk, S. Kolemen, G. Gulseren, T. Nalbantoglu, H. Boyaci, E. U.
Akkaya, J. Am. Chem. Soc. 2010, 132, 8029. b) O. A. Bozdemir, F.
Sozmen, O. Buyukcakir, R. Guliyev, Y. Cakmak, E. U. Akkaya, Org.
Lett. 2010, 12, 1400. c) S. Yin, V. Leen, S. V. Snick, N. Boens, W.
Dehaen, Chem. Commun. 2010, 46, 6329. d) K. Krumova, P. Oleynik,
P. Karam, G. Cosa, J. Org. Chem. 2009, 74, 3641. e) T. W. Hudnall,
F. P. Gabbaï, Chem. Commun. 2008, 4596.
15 a) M. Yuan, W. Zhou, X. Liu, M. Zhu, J. Li, X. Yin, H. Zheng, Z. Zuo,
C. Ouyang, H. Liu, Y. Li, D. Zhu, J. Org. Chem. 2008, 73, 5008. b) M.
Yuan, Y. Li, J. Li, C. Li, X. Liu, J. Lv, J. Xu, H. Liu, S. Wang, D. Zhu,
Org. Lett. 2007, 9, 2313. c) J. Wang, X. Qian, Org. Lett. 2006, 8, 3721.
d) T. Cheng, Y. Xu, S. Zhang, W. Zhu, X. Qian, L. Duan, J. Am. Chem.
Soc. 2008, 130, 16160. e) X. Peng, J. Du, J. Fan, J. Wang, Y. Wu, J.
Zhao, S. Sun, T. Xu, J. Am. Chem. Soc. 2007, 129, 1500. f) Y. Wu, X.
Peng, B. Guo, J. Fan, Z. Zhang, J. Wang, A. Cui, Y. Gao, Org. Biomol.
Chem. 2005, 3, 1387. g) L. Jiao, J. Li, S. Zhang, C. Wei, E. Hao,
M. G. H. Vicente, New J. Chem. 2009, 33, 1888.
This work is supported by the National Nature Science
Foundation of China (Grants Nos. 20802002, 20902004, and
21072005) and fundings from Anhui Province (Grant
Nos. 090416221 and KJ2009A130). We thank Professor G. S.
Yang for the help with the NMR analysis.
References and Notes
1
2
3
4
J. Ma, P. K. Dasgupta, Anal. Chim. Acta 2010, 673, 117.
Z. Xu, X. Chen, H. N. Kim, J. Yoon, Chem. Soc. Rev. 2010, 39, 127.
F. H. Zelder, C. Männel-Croisé, Chimia 2009, 63, 58.
Some examples: a) S.-J. Hong, J. Yoo, S.-H. Kim, J. S. Kim, J. Yoon,
C.-H. Lee, Chem. Commun. 2009, 189. b) S.-H. Kim, S.-J. Hong, J.
Yoo, S. K. Kim, J. L. Sessler, C.-H. Lee, Org. Lett. 2009, 11, 3626. c)
R. Guliyev, O. Buyukcakir, F. Sozmen, O. A. Bozdemir, Tetrahedron
Lett. 2009, 50, 5139. d) J. O. Huh, Y. Do, M. H. Lee, Organometallics
2008, 27, 1022. e) F. H. Zelder, Inorg. Chem. 2008, 47, 1264. f) H.-T.
Niu, X. Jiang, J. He, J.-P. Cheng, Tetrahedron Lett. 2008, 49, 6521. g)
Y. M. Chung, B. Raman, D.-S. Kim, K. H. Ahn, Chem. Commun.
2006, 186. h) M. Tomasulo, S. Sortino, A. J. P. White, F. M. Raymo,
J. Org. Chem. 2006, 71, 744. i) C.-L. Chen, Y.-H. Chen, C.-Y. Chen,
S.-S. Sun, Org. Lett. 2006, 8, 5053. j) J. V. Ros-Lis, R. Martínez-
Máñez, J. Soto, Chem. Commun. 2005, 5260.
5
6
a) X. Lou, L. Zhang, J. Qin, Z. Li, Chem. Commun. 2008, 5848. b) H.
Miyaji, J. L. Sessler, Angew. Chem., Int. Ed. 2001, 40, 154.
a) D.-G. Cho, J. H. Kim, J. L. Sessler, J. Am. Chem. Soc. 2008, 130,
12163. b) K.-S. Lee, H.-J. Kim, G.-H. Kim, I. Shin, J.-I. Hong, Org.
Lett. 2008, 10, 49. c) T. W. Hudnall, F. P. Gabbai, J. Am. Chem. Soc.
2007, 129, 11978. d) Y. Chung, H. Lee, K. H. Ahn, J. Org. Chem.
2006, 71, 9470. e) M. Tomasulo, F. M. Raymo, Org. Lett. 2005, 7,
4633.
16 Supporting Information is available electronically on the CSJ-Journal
Web site, http://www.csj.jp/journals/chem-lett/index.html.
7
a) S. Vallejos, P. Estévez, F. C. García, F. Serna, J. L. de la Peña, J. M.
García, Chem. Commun. 2010, 46, 7951. b) F.-J. Huo, J. Su, Y.-Q. Sun,
C.-X. Yin, J.-B. Chao, Chem. Lett. 2010, 39, 738. c) C. Männel-Croisé,
F. Zelder, Inorg. Chem. 2009, 48, 1272. d) X. Lou, L. Qiang, J. Qin, Z.
17 M. Zhu, M. Yuan, X. Liu, J. Xu, J. Lv, C. Huang, H. Liu, Y. Li, S.
Wang, D. Zhu, Org. Lett. 2008, 10, 1481.
18 a) E. Krogh, P. Wan, Top. Curr. Chem. 1990, 156, 93. b) H. Sunahara,
Y. Urano, H. Kojima, T. Nagano, J. Am. Chem. Soc. 2007, 129, 5597.
Chem. Lett. 2011, 40, 623-625
© 2011 The Chemical Society of Japan
www.csj.jp/journals/chem-lett/