- Email: [email protected]
A colorimetric chemosensor for fluoride ions based on an indigo derivative
Accepted Manuscript Title: A colorimetric chemosensor for fluoride ions based on an indigo derivative Author: SuJuan Wang YanLei Zhao Chunxia Zhao Lei Liu ShuangJun Yu PII: DOI: Reference:
S0022-1139(13)00324-2 http://dx.doi.org/doi:10.1016/j.jfluchem.2013.09.012 FLUOR 8199
To appear in:
FLUOR
Received date: Revised date: Accepted date:
20-5-2013 22-9-2013 24-9-2013
Please cite this article as: S.J. Wang, Y.L. Zhao, C. Zhao, L. Liu, S.J. Yu, A colorimetric chemosensor for fluoride ions based on an indigo derivative, Journal of Fluorine Chemistry (2013), http://dx.doi.org/10.1016/j.jfluchem.2013.09.012 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.
A colorimetric chemosensor for fluoride ions based on an indigo derivative
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SuJuan Wanga*,YanLei Zhaoa, Chunxia Zhaoa, Lei Liua, ShuangJun Yub
a
an
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College of Chemistry and Environment Science, Hebei University, Baoding, P. R. China b Tangshan CaoFeidian Industrial Park of Equipment Manufacture, Tangshan, P. R. China
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Abstract: A novel indigo derivative (1) was synthesized and fully characterized. Its structure, confirmed by X-ray crystallography, showed that compound 1 is a planar molecule. Interestingly, compound 1 only has
d
response to fluoride ions among six different anions (F-, Cl-, Br-, I-, AcO-,
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and HSO4-) in an anhydrous methylene chloride solution and this response
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can be detected by the ‘naked eyes’. Keywords: Indigo, Boron trifluoride complex, Colorimetric chemosensor, fluoride ion
* Corresponding author at: College of Chemistry and Environment Science, Hebei University, Baoding, P. R. China Tel: 86-312-5079317 E-mail address: [email protected]
1
Page 1 of 16
1. Introduction During the past decade, highly sensitive and selective chemosensors for ions and biomolecules have attracted a lot of scientists [1-14]. Especially, sensors based on
ip t
organic conjugated molecules and polymers (which can generate electrochemical and optical responses) can be easily tailored to specially sense one or two ions through
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simple modification. Using organic probes to detect one or two anions is more
us
challenging because other anions might affect the response to a special anion. Among all anions, fluoride ion is very important in biosystem and can prevent dental carries
an
and osteoporosis [15-17]. However, excess or deficient fluoride ion can not only cause pain in the legs and incomplete stress fractures, but also result in accidental and
M
suicidal deaths from acute poisoning [18-19]. Therefore, the fast and efficient detection of fluoride ions is very urgent.
d
Currently, the chemosensors for fluoride ion are based on naphthalene derivatives
te
[20-24], coumarin derivatives [25-26], cyclopyrrole derivatives [27], indole compounds [28], Bis(σ-fluorophenylacetylide) Platinum(II) complexes [29] and
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organoboron compounds [30-31]. However, a new receptor with higher sensitivity and selectivity is still required because ideal sensors not only offer the qualitative or quantitative information but can be used for rapid visual sensing. This gap strongly encourages us to design and prepare a novel fluoride chemosensor based on a new indigo derivative.
As one family of organic natural molecules, indigos with donor (-NH) and
–acceptor (-C=O) structures have been widely studied in organic field effect transistors [32]. In addition, their properties could be further tuned through putting different substituted groups in the central region or the benzene rings [33-36]. For example, Melo and Voss groups have prepared a series of novel indigo derivatives and
2
Page 2 of 16
studied their physical properties in detail [37-38]. However, using these compounds to detect ions is rare. Herein, we report the synthesis and characterization of a novel BF2-complexed indigo compound 1 (Scheme 1) and its positive response to the
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fluoride anion. 2. Results and discussion
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The synthetic procedure for compound 1 is shown in Scheme 2. Compound 1 was
synthesized as a violet solid through a one-step reaction of indigo and BF3·Et2O using
us
methylene chloride as a solvent in the presence of dry Et3N at 40 oC (Scheme 2). The
an
as-prepared compound 1 was fully characterized through FT-IR, 1H NMR, 13C NMR, and MS mass spectroscopes, which were summarized in the supporting information.
M
Thermal gravimetric analysis (TGA) indicated that compound 1 is stable up to 300 oC (see the supporting information, Figure S1). Compound 1 is soluble in common
d
organic solvents such as methylene chloride, chloroform, tetrahydrofuran (THF),
te
acetonitrile, N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). To further precisely understand the structure of compound 1, single crystal study has
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been demonstrated. Single crystals suitable for X-ray diffraction analysis were obtained by the slow evaporation of methylene chloride/n-hexane (v/v, 1:1) at room temperature. Figure 1a shows the labeled structure of compound 1 [39]. Compound 1 has a triclinic crystal system, belonging to the space group P1 with the unit cell parameters of a = 9.0799(18) Å, b = 9.2486(18) Å, c = 9.2486(18) Å, α = 76.54(3)o, β = 65.06(3)o, and γ =
65.06(3)o. As shown in Figure 1b, the packing model of compound 1 had a short
interplanar distance (3.34 Å), indicating that there is the strong π-π stacking interactions between neighboring molecules. The response behavior to fluoride ion for compound 1 was analyzed in anhydrous methylene chloride, as shown as in Figure 2. Indigo in methylene chloride/DMSO
3
Page 3 of 16
(v/v, 19:1) has single monomeric absorption peak with a maximum at 600 nm (see the supporting information, FS 2). In contrast to the indigo molecule, the BF3-functionalized compound 1 (3 × 10-5 M) displays a broad absorption band
ip t
(500-700 nm) with λmax at 620-660 nm. Such a broad peak might be due to the electronic transitions being delocalized throughout the electron-donating group and
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the electron-withdrawing unit[40-45]. The addition of fluoride ion (0-6.0×10-4 M) in the form of a tetrabutylammonium salt led to a decrease in the intensity of the primary
us
peaks at 620-660 nm, with the concomitant growth of a blue-shifted band at 580 nm.
an
It should be noted that the intensity of the band at 580 nm reached a constant value at 20 equiv of fluoride ion at room temperature. Meanwhile, several isosbestic points at
M
328, 380, 504, 593, and 718 nm were observed, which not only indicated the formation of a new complex but also exhibited an obvious visible response to fluoride
d
anions. In addition, the Job’s plot experiment between compound 1 and fluoride anion
te
with a total concentration of 1 × 10-4 M in anhydrous methylene chloride displays a 1:1 stoichiometric ratio (see the supporting information, Figure S3). Accordingly, the
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binding constant between compound 1 and fluoride ion was determined through nonlinear least-squares curve fitness [46]. The value of this complex was calculated to be 8.6 × 104 M-2.
A possible explanation for the interaction between compound 1 and the fluoride
anion is as follows: upon the addition of the fluoride ion, the –NH group is deprotonated and blocks the intramolecular charge transfer (ICT) from the donor moiety to the acceptor units as shown as in Figure 3a [40-42]. To obtain further evidence of the formation of this complex, the 1H NMR spectroscopic studies in
DMSO-d6 were carried out. Figure 3b displays the partial 1H NMR spectra in the absence and presence of fluoride anion. The signal peak belonging to the –NH group
4
Page 4 of 16
at 11.79 was completely disappeared upon addition of fluoride tetrabutylammonium. Based on the 1H NMR spectra and the similar reported experimental phenomena [22, 24, 43-45], we do believe that the disappearance of the peak for –NH group can be
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ascribed to the strong hydrogen bonding with the fluoride anions.
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To confirm the specificity, absorption experiments were also performed with other anions including Cl-, Br-, I-, AcO-, HSO4-. As shown as in Figure 4A, except for F-,
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which exhibits an obvious blue-shift in the UV absorption, no changes were observed
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in the UV-vis spectra of other anions. This lack of changes is the result of the fact that the other anions have low affinities for compound 1. Figure 4B shows the color
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changes. Our experimental results clearly indicate that compound 1 can be utilized as
3. Experimental
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inspection.
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selective and sensitive colorimetric sensors for the fluoride ion by simple visual
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3.1 General experimental section
Column chromatography: SiO2 (200-300 mesh). Indigo, borontrifluoride diethyl
etherate, and chromatographical methylene chloride was commercially obtained from J&K corporation company. Triethylamine was dried with CaH2 and then followed by distillation.
FT-IR spectrum was carried out on a Nicolet 380 instrument. UV-vis spectra were
measured on a Shimadzu UV-2550 spectrometer. 1H NMR and 13C NMR spectra were performed on Bruker 600 spectrometers using DMSO-d6 as a solvent. X-ray crystallographic data were obtained with a Bruker APEX ІІ CCD diffractometer with a graphite-monochromatic Mo Kα radiation (λ= 0.71073 Å) at 298 K.
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3.2 Synthesis of compound 1 Boron trifluoride diethyl etherate (2 mL) was added to a stirred mixture of indigo (524 g, 2 mmol), anhydrous Et3N (1 mL), and anhydrous methylene chloride (60 mL)
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under nitrogen at refluxing temperature. After 24 h, the reaction solution was cooled to room temperature, and washed with brine solution, and then directly extracted with
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methylene chloride (4 × 40 mL). The obtained crude product was purified by column
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chromatography on silica gel with methylene chloride to afford compound 1 (101 mg, 17 %). FT-IT (KBr), 3391, 1702, 1650, 1592, 1524, 1456, 1303, 1125, 1030, 930, 747
an
cm-1. 1H NMR (600 MHz, DMSO-d6, 298 K): δ = 11.792 (s, 1H), 7.804 (t, J = 7.8 Hz, 2H), 7.713 (t, J = 7.8 Hz, 1H), 7.593 (t, J = 7.8 Hz, 1H), 7.446 (d, J = 7.2 Hz, 1H), 13
C
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7.402 (d, J = 7.8 Hz, 1H), 7.285 (t, J = 7.8 Hz, 1H), 7.114 (t, J = 7.8 Hz, 1H).
NMR (150 MHz, DMSO-d6, 298 K): δ = 188.31, 187.68, 164.01, 153.23, 148.40,
d
137.99, 136.19, 135.01, 126.24, 123.87, 122.61, 121.52, 120.54, 116.31, 114.61,
4
Conclusions
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113.88. MS (EI): Calc. for C16H9BF2N2O2: [M] 310.07, Found: [M] 310.
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In conclusion, we successfully prepared a new BF3-complexed indigo derivative 1 that can be used as a fluoride ion sensor. The fluoride anion can block ICT processes, and the resulting color change can be easily detected by the naked eye. Acknowledgements
This work was financially supported by .the Ph.D. Programs Foundation of the Ministry of Education of China (20101301120004), the Science Research Project of the Department of Education of Hebei Province (2009106) References [1] A. J. Zucchero, P. L. Mcgrier, U. H. F. Bunz, Acc. Chem. Res., 43 (2010)
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397-408. [2] X. L. Feng, L. B. Liu, S. Wang, D. B. Zhu, Chem. Soc. Rev., 39 (2010) 2411-2419.
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[3] S. W. Thomas III, G. D. Joly, T. M. Swager, Chem. Rev., 107 (2007) 1339-1386. [4] A. Ojida, I. Takashima, T. Kohira, H. Nonaka, I. Hamachi, J. Am. Chem. Soc.,
cr
130 (2008) 12095-12101.
[5] Y. T. Wang, J. C. Xiao, S. J. Wang, B. Yang, X. W. Ba, Supramolecular Chemistry,
us
22 (2010) 380-386.
an
[6] Y. H. Zhao, H. Pan, G. L. Fu, J. M. Lin, C. H. Zhao, Tetrahedron Lett., 52 (2011) 3832-3835.
M
[7] R. Martínez-Mánez, F. Sancenón, Chem. Rev., 103 (2003) 4419-4476. [8] C. Caltagirone, P. A. Gale, Chem. Soc. Rev., 38 (2009) 520-563.
d
[9] P. A. Gale, S. E. García-Garrido, J. Garric, Chem. Soc. Rev., 37 (2008) 151-190.
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[10] P. D. Beer, P. A. Gale, Angew. Chem. Int. Ed., 40 (2001) 486-516. [11] K. Užarević, D. Dilović Matković-Ćalogović, D. Šišak, M. Cindrić, Angew. Chem.
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Int. Ed., 47 (2008) 7022-7025.
[12] P. Dechambenoit, S. Ferlay, N. Kyritsakas, M. W. Hossein, J. Am. Chem. Soc., 130 (2008) 17106-17113.
[13] M. A. Morikawa, M. Yoshihara, T. Endo, N. Kimizuka, J. Am. Chem. Soc., 127 (2005) 1358-1359.
[14] K. A. Nielsen, W. S. Cho, G. H. Sarova, B. M. Petersen, A. D. Bond, J. Becher, F. Jensen, D. M. Guldi, J. L. Sessler, J. O. Jeppesen, Angew. Chem. Int. Ed., 45 (2006) 6848-6853. [15] K. L. Kirk, Biochemistry of the Elemental Halogens and Inorganic Halides; Plenum Press: New York, 1991.
7
Page 7 of 16
[16] S. Matsuo, K. Kiyamiya, M. Kurebe, Arch. Toxicol, 72 (1998) 798-806. [17] D. Briancon, Rev. Rheum., 64 (1997) 78-81. [18] B. L. Riggs, Bone and Mineal Researchi, Annual 2; Elsevier: Amsterdam, 1984.
CA, 1980.
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[20] S. Guha, S. Sha, J. Am. Chem. Soc., 132 (2010) 17674-17679.
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[19] R. H. Dreisbuch, Handbook of Poisoning; Lange Medial Publishers: Los Altos,
[21] J. F. Zhang, C. S. Lim, S. Bhuniya, B. R. Cho, J. S. Kim, Org. Lett., 13 (2011)
us
1190-1193.
an
[22] S. V. Bhosale, S. V. Bhosale, M. B. Kalyankar, S. J. Langford, Org. Lett., 11 (2009) 5418-5421.
M
[23] H. M. Yeo, B. J. Ryu, K. C. Nam, Org. Lett., 10 (2008) 2931-2934. [24] E. J. Cho, B. J. Ryu, Y. J. Lee, K. C. Nam, Org. Lett., 7 (2005) 2607-2609.
d
[25] T. H. Kim, T. M. Swager, Angew. Chem. Int. Ed., 42 (2003) 4803-4806.
te
[26] X. W. Cao, W. Y. Lin, Q. X. Yu, J. L. Wang, Org. Lett., 13 (2011) 6098-6101. [27] S. P. Mahanta, B. S. Kumar, S. Baskaran, C. Sivasankar, P. K. Panda, Org. Lett.,
Ac ce p
14 (2012) 548-551.
[28] T. Wang, X. P. Yan, Chem. Eur. J., 16 (2010) 4639-4649. [29] J. Ni, X. Zhang, Y. H. Wu, L. Y. Zhang, Z. N. Chen, Chem. Eur. J., 17 (2011) 1163-1170.
[30] X. Y. Liu, D. R. Bai, S. N. Wang, Angew. Chem. Int. Ed., 45 (2006) 5475-5478. [31] S. Yamaguchi, S. Akiyama, K. Tamao, J. Am. Chem. Soc., 123 (2001) 11372-11375. [32] M. Irimia-Vladu, E. D. Glowacki, P. A. Troshin, G. Schwabegger, L. Leonat, D. K. Susarova, O. Krystal, M. Ullah, Y. Kanbur, M. A. Bodea, V. F. Razumov, H. Sitter, S. Bauer, N. S. Sariciftci, Adv. Mater., 24 (2012) 375-380.
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Page 8 of 16
[33] E. M. Girotto, M. A. De Paoli, Adv. Mater., 10 (1998) 790-793. [34] M. Hein, N. T. B. Phuong, D. Michalik, H. Görls, M. Lalk, P. Langer, Tetrahedron Lett., 47 (2006) 5741-5745.
ip t
[35] J. S. D. Melo, R. Rondão, H. D. Burrows, M. J. Melo, S. Navaratnam, J. Phys. Chem. A, 110 (2006) 13653-13661.
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[36] S. R. Oakley, G. Nawn, K. M. Waldie, T. D. MacInnis, B. O. Patrick, R. G. Hicks, Chem. Commun., (2010) 6753-6755.
us
[37] G. Voss, M. Gradzielski, J. Heinze, H. Reinke, C. Unverzagt, Helv. Chim. Acta.,
an
86 (2003) 1982-1985.
[38] J. S. S. D. Melo, R. Rondão, H. D. Burrows, M. J. Melo, S. Navaratnam, R. Edge,
M
G. Voss, Chem. Phys. Chem., 7 (2006) 2303-2311.
[39] Crystal data for compound 1: C16H9BF2N2O2 1: M = 310.06, crystal size:
d
0.25×0.16×0.10 mm, triclinic, P-1, a = 9.0799(18), b = 9.2486(18), c = 9.2486(18),
te
α = 76.54 (3)o, β = 65.06(3)o, γ = 65.06(3)o, V = 637.14Å3, Z = 2, T = 174 K, Dc = 1.616 mg m-3. CCDC 881406.
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[40] Z. R. Grabowski, K. Rotkiewicz, W. Rettig, Chem. Rev., 103 (2003) 3899-4301. [41] J. S. S. D. Melo, H. D. Burrows, C. Serpa, L. G. Arnaut, Angew. Chem. Int. Ed., 46 (2007) 2094-2096.
[42] G. J. Zhao, R. K. Chen, M. T. Sun, J. Y. Liu, G. Y. Li, Y. L. Gao, K. L. Han, X. C. Yang, L. C. Sun, Chem. Eur. J., 14 (2008) 6935-6947.
[43] M. Vázqez, L. Fabbrizzi, A. Taglietti, R. M. Pedrido, A. M. González-Noya, M. R. Bermejo, Angew. Chem. Int. Ed., 43 (2004) 1962-1964. [44] D. A. Jose, D. K. Kumar, B. Ganguly, A. Das, Org. Lett., 6 (2004) 3445-3448. [45] Y. Qu, J. L. Hua, H. Tian, Org. Lett., 12 (2010) 3320-3323. [46] J. Li, X. Yu, X. Liu, Y. Gao, Y. Zeng, Q. Hu, J. Guo, Z. Pan, Sensor Lett., 9 (2011)
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an
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1331-1341.
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Page 10 of 16
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Scheme 1 The chemical structure of compound 1
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Scheme 2 Synthetic procedure for compound 1
Fig. 1. (a) X-ray structure and (b) molecular packing of compound 1. Carbon, oxygen, nitrogen, fluoride, and boron atoms are colored gray, red, blue, purple, and green respectively.
11
Page 11 of 16
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Fig. 2. Changes in the UV-vis absorption spectrum of compound 1 in CH2Cl2 solution
an
upon addition of TBAF: [1] = 3.0 × 10-5 M, (a) 0, (b) 6.0 × 10-5 M, (c) 1.2 × 10-4 M, (d) 1.8 × 10-4 M, (e) 2.4 × 10-4 M, (f) 3.0 × 10-4 M, and (g) 6.0 × 10-4 M. The inset
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te
d
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shows the ratio of A580/A660 against the fluoride ion concentration.
Fig. 3. (a) The possible reaction mechanism of compound 1 and fluoride ion. (b) Partial 1H NMR spectra of compound 1 in DMSO-d6 in the absence (ii) and (i) presence of TBAF at 298 K.
12
Page 12 of 16
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Fig. 4. (A) UV-vis absorption spectra changes of compound 1 in dry methylene
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chloride upon addition of different ions. (B) Color change of compound 1 in the
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1+AcO-, (g) 1+HSO4-.
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presence of different ions: (a) blank, (b) 1+F-, (c) 1+Cl-, (d) 1+Br-, (e) 1+I-, (f)
13
Page 13 of 16
A Colorimetric Chemosensor for Fluoride Ions Based on an Indigo Derivative
Ac ce p
te
d
M
an
us
cr
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Sujuan Wang*, Yanlei Zhao,Chunxia Zhao, Lei Liu, Shuangjun Yu
14
Page 14 of 16
Ac ce p
te
d
M
an
us
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The positive response of indigo derivative to fluoride ions was studied in dichloromethane solution.
15
Page 15 of 16
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an
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Highlights A novel Indigo derivative (1) was synthesized and characterized. Single crystal analysis shows that compound 1 is a planar molecule. Its positive response to fluoride ions can be directly detected by the ‘naked eyes’.
Page 16 of 16
S0022-1139(13)00324-2 http://dx.doi.org/doi:10.1016/j.jfluchem.2013.09.012 FLUOR 8199
To appear in:
FLUOR
Received date: Revised date: Accepted date:
20-5-2013 22-9-2013 24-9-2013
Please cite this article as: S.J. Wang, Y.L. Zhao, C. Zhao, L. Liu, S.J. Yu, A colorimetric chemosensor for fluoride ions based on an indigo derivative, Journal of Fluorine Chemistry (2013), http://dx.doi.org/10.1016/j.jfluchem.2013.09.012 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.
A colorimetric chemosensor for fluoride ions based on an indigo derivative
cr
ip t
SuJuan Wanga*,YanLei Zhaoa, Chunxia Zhaoa, Lei Liua, ShuangJun Yub
a
an
us
College of Chemistry and Environment Science, Hebei University, Baoding, P. R. China b Tangshan CaoFeidian Industrial Park of Equipment Manufacture, Tangshan, P. R. China
M
Abstract: A novel indigo derivative (1) was synthesized and fully characterized. Its structure, confirmed by X-ray crystallography, showed that compound 1 is a planar molecule. Interestingly, compound 1 only has
d
response to fluoride ions among six different anions (F-, Cl-, Br-, I-, AcO-,
te
and HSO4-) in an anhydrous methylene chloride solution and this response
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can be detected by the ‘naked eyes’. Keywords: Indigo, Boron trifluoride complex, Colorimetric chemosensor, fluoride ion
* Corresponding author at: College of Chemistry and Environment Science, Hebei University, Baoding, P. R. China Tel: 86-312-5079317 E-mail address: [email protected]
1
Page 1 of 16
1. Introduction During the past decade, highly sensitive and selective chemosensors for ions and biomolecules have attracted a lot of scientists [1-14]. Especially, sensors based on
ip t
organic conjugated molecules and polymers (which can generate electrochemical and optical responses) can be easily tailored to specially sense one or two ions through
cr
simple modification. Using organic probes to detect one or two anions is more
us
challenging because other anions might affect the response to a special anion. Among all anions, fluoride ion is very important in biosystem and can prevent dental carries
an
and osteoporosis [15-17]. However, excess or deficient fluoride ion can not only cause pain in the legs and incomplete stress fractures, but also result in accidental and
M
suicidal deaths from acute poisoning [18-19]. Therefore, the fast and efficient detection of fluoride ions is very urgent.
d
Currently, the chemosensors for fluoride ion are based on naphthalene derivatives
te
[20-24], coumarin derivatives [25-26], cyclopyrrole derivatives [27], indole compounds [28], Bis(σ-fluorophenylacetylide) Platinum(II) complexes [29] and
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organoboron compounds [30-31]. However, a new receptor with higher sensitivity and selectivity is still required because ideal sensors not only offer the qualitative or quantitative information but can be used for rapid visual sensing. This gap strongly encourages us to design and prepare a novel fluoride chemosensor based on a new indigo derivative.
As one family of organic natural molecules, indigos with donor (-NH) and
–acceptor (-C=O) structures have been widely studied in organic field effect transistors [32]. In addition, their properties could be further tuned through putting different substituted groups in the central region or the benzene rings [33-36]. For example, Melo and Voss groups have prepared a series of novel indigo derivatives and
2
Page 2 of 16
studied their physical properties in detail [37-38]. However, using these compounds to detect ions is rare. Herein, we report the synthesis and characterization of a novel BF2-complexed indigo compound 1 (Scheme 1) and its positive response to the
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fluoride anion. 2. Results and discussion
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The synthetic procedure for compound 1 is shown in Scheme 2. Compound 1 was
synthesized as a violet solid through a one-step reaction of indigo and BF3·Et2O using
us
methylene chloride as a solvent in the presence of dry Et3N at 40 oC (Scheme 2). The
an
as-prepared compound 1 was fully characterized through FT-IR, 1H NMR, 13C NMR, and MS mass spectroscopes, which were summarized in the supporting information.
M
Thermal gravimetric analysis (TGA) indicated that compound 1 is stable up to 300 oC (see the supporting information, Figure S1). Compound 1 is soluble in common
d
organic solvents such as methylene chloride, chloroform, tetrahydrofuran (THF),
te
acetonitrile, N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). To further precisely understand the structure of compound 1, single crystal study has
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been demonstrated. Single crystals suitable for X-ray diffraction analysis were obtained by the slow evaporation of methylene chloride/n-hexane (v/v, 1:1) at room temperature. Figure 1a shows the labeled structure of compound 1 [39]. Compound 1 has a triclinic crystal system, belonging to the space group P1 with the unit cell parameters of a = 9.0799(18) Å, b = 9.2486(18) Å, c = 9.2486(18) Å, α = 76.54(3)o, β = 65.06(3)o, and γ =
65.06(3)o. As shown in Figure 1b, the packing model of compound 1 had a short
interplanar distance (3.34 Å), indicating that there is the strong π-π stacking interactions between neighboring molecules. The response behavior to fluoride ion for compound 1 was analyzed in anhydrous methylene chloride, as shown as in Figure 2. Indigo in methylene chloride/DMSO
3
Page 3 of 16
(v/v, 19:1) has single monomeric absorption peak with a maximum at 600 nm (see the supporting information, FS 2). In contrast to the indigo molecule, the BF3-functionalized compound 1 (3 × 10-5 M) displays a broad absorption band
ip t
(500-700 nm) with λmax at 620-660 nm. Such a broad peak might be due to the electronic transitions being delocalized throughout the electron-donating group and
cr
the electron-withdrawing unit[40-45]. The addition of fluoride ion (0-6.0×10-4 M) in the form of a tetrabutylammonium salt led to a decrease in the intensity of the primary
us
peaks at 620-660 nm, with the concomitant growth of a blue-shifted band at 580 nm.
an
It should be noted that the intensity of the band at 580 nm reached a constant value at 20 equiv of fluoride ion at room temperature. Meanwhile, several isosbestic points at
M
328, 380, 504, 593, and 718 nm were observed, which not only indicated the formation of a new complex but also exhibited an obvious visible response to fluoride
d
anions. In addition, the Job’s plot experiment between compound 1 and fluoride anion
te
with a total concentration of 1 × 10-4 M in anhydrous methylene chloride displays a 1:1 stoichiometric ratio (see the supporting information, Figure S3). Accordingly, the
Ac ce p
binding constant between compound 1 and fluoride ion was determined through nonlinear least-squares curve fitness [46]. The value of this complex was calculated to be 8.6 × 104 M-2.
A possible explanation for the interaction between compound 1 and the fluoride
anion is as follows: upon the addition of the fluoride ion, the –NH group is deprotonated and blocks the intramolecular charge transfer (ICT) from the donor moiety to the acceptor units as shown as in Figure 3a [40-42]. To obtain further evidence of the formation of this complex, the 1H NMR spectroscopic studies in
DMSO-d6 were carried out. Figure 3b displays the partial 1H NMR spectra in the absence and presence of fluoride anion. The signal peak belonging to the –NH group
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at 11.79 was completely disappeared upon addition of fluoride tetrabutylammonium. Based on the 1H NMR spectra and the similar reported experimental phenomena [22, 24, 43-45], we do believe that the disappearance of the peak for –NH group can be
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ascribed to the strong hydrogen bonding with the fluoride anions.
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To confirm the specificity, absorption experiments were also performed with other anions including Cl-, Br-, I-, AcO-, HSO4-. As shown as in Figure 4A, except for F-,
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which exhibits an obvious blue-shift in the UV absorption, no changes were observed
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in the UV-vis spectra of other anions. This lack of changes is the result of the fact that the other anions have low affinities for compound 1. Figure 4B shows the color
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changes. Our experimental results clearly indicate that compound 1 can be utilized as
3. Experimental
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inspection.
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selective and sensitive colorimetric sensors for the fluoride ion by simple visual
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3.1 General experimental section
Column chromatography: SiO2 (200-300 mesh). Indigo, borontrifluoride diethyl
etherate, and chromatographical methylene chloride was commercially obtained from J&K corporation company. Triethylamine was dried with CaH2 and then followed by distillation.
FT-IR spectrum was carried out on a Nicolet 380 instrument. UV-vis spectra were
measured on a Shimadzu UV-2550 spectrometer. 1H NMR and 13C NMR spectra were performed on Bruker 600 spectrometers using DMSO-d6 as a solvent. X-ray crystallographic data were obtained with a Bruker APEX ІІ CCD diffractometer with a graphite-monochromatic Mo Kα radiation (λ= 0.71073 Å) at 298 K.
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3.2 Synthesis of compound 1 Boron trifluoride diethyl etherate (2 mL) was added to a stirred mixture of indigo (524 g, 2 mmol), anhydrous Et3N (1 mL), and anhydrous methylene chloride (60 mL)
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under nitrogen at refluxing temperature. After 24 h, the reaction solution was cooled to room temperature, and washed with brine solution, and then directly extracted with
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methylene chloride (4 × 40 mL). The obtained crude product was purified by column
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chromatography on silica gel with methylene chloride to afford compound 1 (101 mg, 17 %). FT-IT (KBr), 3391, 1702, 1650, 1592, 1524, 1456, 1303, 1125, 1030, 930, 747
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cm-1. 1H NMR (600 MHz, DMSO-d6, 298 K): δ = 11.792 (s, 1H), 7.804 (t, J = 7.8 Hz, 2H), 7.713 (t, J = 7.8 Hz, 1H), 7.593 (t, J = 7.8 Hz, 1H), 7.446 (d, J = 7.2 Hz, 1H), 13
C
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7.402 (d, J = 7.8 Hz, 1H), 7.285 (t, J = 7.8 Hz, 1H), 7.114 (t, J = 7.8 Hz, 1H).
NMR (150 MHz, DMSO-d6, 298 K): δ = 188.31, 187.68, 164.01, 153.23, 148.40,
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137.99, 136.19, 135.01, 126.24, 123.87, 122.61, 121.52, 120.54, 116.31, 114.61,
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Conclusions
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113.88. MS (EI): Calc. for C16H9BF2N2O2: [M] 310.07, Found: [M] 310.
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In conclusion, we successfully prepared a new BF3-complexed indigo derivative 1 that can be used as a fluoride ion sensor. The fluoride anion can block ICT processes, and the resulting color change can be easily detected by the naked eye. Acknowledgements
This work was financially supported by .the Ph.D. Programs Foundation of the Ministry of Education of China (20101301120004), the Science Research Project of the Department of Education of Hebei Province (2009106) References [1] A. J. Zucchero, P. L. Mcgrier, U. H. F. Bunz, Acc. Chem. Res., 43 (2010)
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397-408. [2] X. L. Feng, L. B. Liu, S. Wang, D. B. Zhu, Chem. Soc. Rev., 39 (2010) 2411-2419.
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[3] S. W. Thomas III, G. D. Joly, T. M. Swager, Chem. Rev., 107 (2007) 1339-1386. [4] A. Ojida, I. Takashima, T. Kohira, H. Nonaka, I. Hamachi, J. Am. Chem. Soc.,
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130 (2008) 12095-12101.
[5] Y. T. Wang, J. C. Xiao, S. J. Wang, B. Yang, X. W. Ba, Supramolecular Chemistry,
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22 (2010) 380-386.
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[6] Y. H. Zhao, H. Pan, G. L. Fu, J. M. Lin, C. H. Zhao, Tetrahedron Lett., 52 (2011) 3832-3835.
M
[7] R. Martínez-Mánez, F. Sancenón, Chem. Rev., 103 (2003) 4419-4476. [8] C. Caltagirone, P. A. Gale, Chem. Soc. Rev., 38 (2009) 520-563.
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[9] P. A. Gale, S. E. García-Garrido, J. Garric, Chem. Soc. Rev., 37 (2008) 151-190.
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[10] P. D. Beer, P. A. Gale, Angew. Chem. Int. Ed., 40 (2001) 486-516. [11] K. Užarević, D. Dilović Matković-Ćalogović, D. Šišak, M. Cindrić, Angew. Chem.
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Int. Ed., 47 (2008) 7022-7025.
[12] P. Dechambenoit, S. Ferlay, N. Kyritsakas, M. W. Hossein, J. Am. Chem. Soc., 130 (2008) 17106-17113.
[13] M. A. Morikawa, M. Yoshihara, T. Endo, N. Kimizuka, J. Am. Chem. Soc., 127 (2005) 1358-1359.
[14] K. A. Nielsen, W. S. Cho, G. H. Sarova, B. M. Petersen, A. D. Bond, J. Becher, F. Jensen, D. M. Guldi, J. L. Sessler, J. O. Jeppesen, Angew. Chem. Int. Ed., 45 (2006) 6848-6853. [15] K. L. Kirk, Biochemistry of the Elemental Halogens and Inorganic Halides; Plenum Press: New York, 1991.
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[16] S. Matsuo, K. Kiyamiya, M. Kurebe, Arch. Toxicol, 72 (1998) 798-806. [17] D. Briancon, Rev. Rheum., 64 (1997) 78-81. [18] B. L. Riggs, Bone and Mineal Researchi, Annual 2; Elsevier: Amsterdam, 1984.
CA, 1980.
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[20] S. Guha, S. Sha, J. Am. Chem. Soc., 132 (2010) 17674-17679.
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[19] R. H. Dreisbuch, Handbook of Poisoning; Lange Medial Publishers: Los Altos,
[21] J. F. Zhang, C. S. Lim, S. Bhuniya, B. R. Cho, J. S. Kim, Org. Lett., 13 (2011)
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1190-1193.
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[22] S. V. Bhosale, S. V. Bhosale, M. B. Kalyankar, S. J. Langford, Org. Lett., 11 (2009) 5418-5421.
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[23] H. M. Yeo, B. J. Ryu, K. C. Nam, Org. Lett., 10 (2008) 2931-2934. [24] E. J. Cho, B. J. Ryu, Y. J. Lee, K. C. Nam, Org. Lett., 7 (2005) 2607-2609.
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[25] T. H. Kim, T. M. Swager, Angew. Chem. Int. Ed., 42 (2003) 4803-4806.
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[26] X. W. Cao, W. Y. Lin, Q. X. Yu, J. L. Wang, Org. Lett., 13 (2011) 6098-6101. [27] S. P. Mahanta, B. S. Kumar, S. Baskaran, C. Sivasankar, P. K. Panda, Org. Lett.,
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14 (2012) 548-551.
[28] T. Wang, X. P. Yan, Chem. Eur. J., 16 (2010) 4639-4649. [29] J. Ni, X. Zhang, Y. H. Wu, L. Y. Zhang, Z. N. Chen, Chem. Eur. J., 17 (2011) 1163-1170.
[30] X. Y. Liu, D. R. Bai, S. N. Wang, Angew. Chem. Int. Ed., 45 (2006) 5475-5478. [31] S. Yamaguchi, S. Akiyama, K. Tamao, J. Am. Chem. Soc., 123 (2001) 11372-11375. [32] M. Irimia-Vladu, E. D. Glowacki, P. A. Troshin, G. Schwabegger, L. Leonat, D. K. Susarova, O. Krystal, M. Ullah, Y. Kanbur, M. A. Bodea, V. F. Razumov, H. Sitter, S. Bauer, N. S. Sariciftci, Adv. Mater., 24 (2012) 375-380.
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[33] E. M. Girotto, M. A. De Paoli, Adv. Mater., 10 (1998) 790-793. [34] M. Hein, N. T. B. Phuong, D. Michalik, H. Görls, M. Lalk, P. Langer, Tetrahedron Lett., 47 (2006) 5741-5745.
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[35] J. S. D. Melo, R. Rondão, H. D. Burrows, M. J. Melo, S. Navaratnam, J. Phys. Chem. A, 110 (2006) 13653-13661.
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[36] S. R. Oakley, G. Nawn, K. M. Waldie, T. D. MacInnis, B. O. Patrick, R. G. Hicks, Chem. Commun., (2010) 6753-6755.
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[37] G. Voss, M. Gradzielski, J. Heinze, H. Reinke, C. Unverzagt, Helv. Chim. Acta.,
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86 (2003) 1982-1985.
[38] J. S. S. D. Melo, R. Rondão, H. D. Burrows, M. J. Melo, S. Navaratnam, R. Edge,
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G. Voss, Chem. Phys. Chem., 7 (2006) 2303-2311.
[39] Crystal data for compound 1: C16H9BF2N2O2 1: M = 310.06, crystal size:
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0.25×0.16×0.10 mm, triclinic, P-1, a = 9.0799(18), b = 9.2486(18), c = 9.2486(18),
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α = 76.54 (3)o, β = 65.06(3)o, γ = 65.06(3)o, V = 637.14Å3, Z = 2, T = 174 K, Dc = 1.616 mg m-3. CCDC 881406.
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[40] Z. R. Grabowski, K. Rotkiewicz, W. Rettig, Chem. Rev., 103 (2003) 3899-4301. [41] J. S. S. D. Melo, H. D. Burrows, C. Serpa, L. G. Arnaut, Angew. Chem. Int. Ed., 46 (2007) 2094-2096.
[42] G. J. Zhao, R. K. Chen, M. T. Sun, J. Y. Liu, G. Y. Li, Y. L. Gao, K. L. Han, X. C. Yang, L. C. Sun, Chem. Eur. J., 14 (2008) 6935-6947.
[43] M. Vázqez, L. Fabbrizzi, A. Taglietti, R. M. Pedrido, A. M. González-Noya, M. R. Bermejo, Angew. Chem. Int. Ed., 43 (2004) 1962-1964. [44] D. A. Jose, D. K. Kumar, B. Ganguly, A. Das, Org. Lett., 6 (2004) 3445-3448. [45] Y. Qu, J. L. Hua, H. Tian, Org. Lett., 12 (2010) 3320-3323. [46] J. Li, X. Yu, X. Liu, Y. Gao, Y. Zeng, Q. Hu, J. Guo, Z. Pan, Sensor Lett., 9 (2011)
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1331-1341.
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Scheme 1 The chemical structure of compound 1
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Scheme 2 Synthetic procedure for compound 1
Fig. 1. (a) X-ray structure and (b) molecular packing of compound 1. Carbon, oxygen, nitrogen, fluoride, and boron atoms are colored gray, red, blue, purple, and green respectively.
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Fig. 2. Changes in the UV-vis absorption spectrum of compound 1 in CH2Cl2 solution
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upon addition of TBAF: [1] = 3.0 × 10-5 M, (a) 0, (b) 6.0 × 10-5 M, (c) 1.2 × 10-4 M, (d) 1.8 × 10-4 M, (e) 2.4 × 10-4 M, (f) 3.0 × 10-4 M, and (g) 6.0 × 10-4 M. The inset
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shows the ratio of A580/A660 against the fluoride ion concentration.
Fig. 3. (a) The possible reaction mechanism of compound 1 and fluoride ion. (b) Partial 1H NMR spectra of compound 1 in DMSO-d6 in the absence (ii) and (i) presence of TBAF at 298 K.
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Fig. 4. (A) UV-vis absorption spectra changes of compound 1 in dry methylene
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chloride upon addition of different ions. (B) Color change of compound 1 in the
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1+AcO-, (g) 1+HSO4-.
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presence of different ions: (a) blank, (b) 1+F-, (c) 1+Cl-, (d) 1+Br-, (e) 1+I-, (f)
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A Colorimetric Chemosensor for Fluoride Ions Based on an Indigo Derivative
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Sujuan Wang*, Yanlei Zhao,Chunxia Zhao, Lei Liu, Shuangjun Yu
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The positive response of indigo derivative to fluoride ions was studied in dichloromethane solution.
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Highlights A novel Indigo derivative (1) was synthesized and characterized. Single crystal analysis shows that compound 1 is a planar molecule. Its positive response to fluoride ions can be directly detected by the ‘naked eyes’.
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