- Email: [email protected]
A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions
G Model
CCLET 3609 1–5 Chinese Chemical Letters xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Chinese Chemical Letters journal homepage: www.elsevier.com/locate/cclet 1 2 3 4
Original article
A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions
6
Wang, Yan Feng *, Jun Jiang, Wen-Juan Wang, Jiu-You Chen, Hong-Ting Sheng, Xiang-Ming Meng, Man-Zhou Zhu
7
School of Chemistry and Chemical Engineering & Center for Atomic Engineering of Advanced Materials, Anhui University, Hefei 230039, China
5
Q1 Qi
A R T I C L E I N F O
A B S T R A C T
Article history: Received 4 January 2016 Received in revised form 28 January 2016 Accepted 23 February 2016 Available online xxx
We develop a novel coumarin-alkyne derivative (NC7-AL), which can specifically react with Au3+ and give a colorimetric and fluorescent ‘‘turn-on’’ response toward Au3+. Notably, other alkynophilic metal species such as Au+, Ag+, Pd2+, Ni2+, Cu2+, and Hg2+ do not produce an interfering signal. A good linear relationship between emission intensity at 420 nm and Au3+ concentration from 0 to 2 equivalent is observed, and the detection limit (3s/k) is estimated to be ca. 3.58 nmol/L. Harnessing the Au3+-induced color change from light yellow to colorless, we find that NC7-AL-based modified TLC plate can be used for convenient naked-eye detection of Au3+. ß 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.
Keywords: Coumarin Alkyne Au3+ Colorimetric Fluorescent probe
8 9
1. Introduction
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
The noble metal gold (Au) and its salts have attracted intense attention owing to their potentials in catalysis [1,2] and biomedical applications [3–5]. Gold ions are known to activate alkynes for nucleophilic addition, and a series of organic transformations has been carried out according to the characteristic alkynophilicity of gold ions [6–10]. Also, gold-based drugs have been widely used in the treatment of rheumatoid arthritis and tuberculosis [11–13]. However, gold salts such as gold chloride are also highly toxic because they can damage the liver, kidneys, and nervous systems [14–16]. Furthermore, Au3+ ions have strong affinity to DNA, which could lead to the serious damage of DNA via the catalytic cleavage [17–19]. Therefore, it is highly desirable to develop effective methods for the specific, rapid, and real-time monitoring of Au3+ ions in the environment, agrochemicals, and potentially living systems. Fluorescence sensing has become a preferable approach for Au3+ detection because of its high sensitivity and selectivity, versatility, and ease of use [20,21]. Alkynes are often used as the recognition moiety for gold ions, due to their well-acknowledged alkynophilicity. Therefore, introducing a reactive alkyne moiety to the fluorophore could provide an efficient route to developing Au3+-selective fluorescent probes. Representative examples are Au3+-induced
Q2 * Corresponding author.
E-mail address: [email protected] (Y. Feng).
intramolecular cyclization of the rhodamine-based alkynes to yield oxazolecarbaldehyde derivatives [22–25]. Additionally, several alkyne-containing compounds as fluorescent probes for Au3+ ions based on fluorescein [26,27], BODIPY [28], 1,8-naphthalimide [29], and coumarin [30,31] fluorophores are also successfully designed and reported in the literature. However, the most prominent drawback of this sensing mechanism is the cross affinity with other alkynophilic metal species such as Au+, Ag+, Pd2+, Ni2+, Cu2+ and Hg2+, which interferes with the detection of Au3+ ions. Hence, there is an urgent need to develop a fluorescent probe for Au3+ free from the cross-sensitivity of other alkynophilic metal species. Herein, we present a colorimetric and fluorescent probe (NC7AL) for the detection of Au3+ utilizing the characteristic alkynophilicity of gold ions with low detection limit, large Stokes shift, and rapid response. Probe NC7-AL shows a remarkable fluorescence ‘‘turn-on’’ response only toward Au3+ ions over Au+, Ag+, Pd2+, Ni2+, Cu2+, and Hg2+. Upon addition of Au3+ ions, color changes from light yellow to colorless could be observed with the naked eye, and the NC7-AL-based modified TLC plates is an easy and convenient testing method that can be used for Au3+ detection.
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
2. Experimental
51
2.1. Materials and equipments
52
All solvents were purchased and dried according to standard procedures before use. 1H-NMR and 13C-NMR spectra were recorded
53 54
http://dx.doi.org/10.1016/j.cclet.2016.02.021 1001-8417/ß 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
G Model
CCLET 3609 1–5 Q. Wang et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
2
55 56 57 58 59 60 61
on a Bruker Avance II spectrometer at 400 MHz and 100 MHz, respectively. ESI-TOF spectra were recorded over a Waters xevo G2 QT mass spectrometer. UV–vis absorption spectra were recorded on a Shimadzu UV-1800 spectrophotometer. Fluorescence spectra were obtained using a Hitachi F-7000 Fluorescence spectrometer. The fluorescence quantum yields were measured with HORIBA FluoroMax-4P.
62 63
2.2. Synthesis of 7-((4-(dimethylamino)phenyl)ethynyl)-2-oxo-N(prop-2-yn-1-yl)-2H-chromene-3-carboxamide (NC7-AL)
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
A solution of NC7 (0.333 g, 1 mmol), 1-hydroxybenzotriazole (HOBT, 0.203 g, 1.5 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCHCl, 0.211 g, 1.1 mmol), ethyldiisopropylamine (DIPEA, 0.496 mL, 3 mmol), and propargylamine (0.192 mL, 3 mmol) in anhydrous DMF (10 mL) was stirred at r.t. under N2 atmosphere for 24 h. The crude product was extracted with CH2Cl2, washed with brine and purified by column chromatography on silica gel (CH2Cl2:petroleum ether = 1:1, v/v) to afford 0.136 g of NC7-AL as a yellow solid in a 37% yield. 1H NMR (400 MHz, DMSOd6): d 8.91 (t, 1H, J = 5.6 Hz), 8.87 (s, 1H), 7.98 (d, 1H, J = 8.1 Hz), 7.58 (s, 1H), 7.50 (d, 1H, J = 7.8 Hz), 7.42 (d, 2H, J = 8.6 Hz), 6.74 (d, 2H, J = 8.7 Hz), 4.13 (d, 2H, J = 3.2 Hz), 3.16 (s, 1H), 2.98 (s, 6H). 13C NMR (100 MHz, DMSO-d6): d 160.97, 160.08, 153.95, 150.60, 147.16, 132.94, 130.47, 128.92, 127.45, 118.06, 117.81, 117.52, 111.79, 107.12, 96.39, 86.99, 80.70, 73.26, 39.61, 28.70. HRMS (ESI-TOF): m/ z: calcd. For [C23H18N2O3 + H]+: 371.1317, found: 371.1396.
80
2.3. Preparation of test solution
81 82 83 84 85 86 87 88
In this paper, a solution of NC7-AL at 5 mmol/L in CH3CN was used for testing. The solutions of various testing species were prepared in doubly distilled water, and CH3CN-doubly distilled water (1:1, v/v) was used for Au3+ due to solubility problems. Various ions were prepared from AuCl, AuCl3, Ce(NO3)36H2O, Cs2CO3, NaCl, ZnCl2, NiSO46H2O, CrCl36H2O, CoCl2, MnCl24H2O, CaCl2, MgSO4, BaCl2, KCl, CuCl2, CuI, FeCl24H2O, FeCl3, AgNO3, HgCl2, PdCl2, and n-Bu4N+CN .
89
3. Results and discussion
90
3.1. Synthesis of probe NC7-AL
91 92 93 94 95
Compound NC7 was synthesized from salicylaldehyde following literature procedures [32,33]. Condensation of NC7 with propargylamine afforded NC7-AL as a yellow powder in a 37% yield (Scheme 1). The structure of NC7-AL was confirmed by 1H NMR, 13 C NMR, and HR-MS.
3.2. Spectroscopic properties
96
The UV–vis and fluorescence spectra of NC7-AL (5 mmol/L) were investigated in CH3CN. As shown in Fig. 1, the NC7-AL solution displayed almost no fluorescence. Addition of Au3+ to this solution resulted in enhancement of an emission band at 420 nm upon excitation at 360 nm. The emission intensity reached its maximum with ca. 6 equivalent of Au3+. An approximate 200-fold fluorescence enhancement could be observed accompanied by a quantum yield increase from <0.1% to 18.5%. The UV–vis spectra of NC7-AL displayed a similar sensing behavior toward the addition of Au3+. NC7-AL showed two absorption bands at 300 nm and 422 nm. With the addition of Au3+ (10 equivalent), the absorption band at 422 nm diminished, and a new absorption band with a maximum at 330 nm gradually increased. Concomitantly, the solution color changed from light yellow to colorless, facilitating direct observation by the naked eyes. A well-defined isosbestic point at 378 nm was found indicating a desired one-to-one type clean conversion. The Stokes shift was as large as 90 nm, which could minimize self-quenching. We studied the kinetics of the fluorescence enhancement resulting from the addition of Au3+ (6 equivalent) to the solution of probe NC7-AL. As shown in Fig. S1 in Supporting information, the fluorescence intensity reached its maximum in ca. 20 s. Thus, all testing of UV–vis absorption and fluorescence were performed after 1 min. Moreover, a good linear relationship between the dosage of Au3+ (from 0 to 2 equivalent) and the emission intensity was observed (Fig. S2 in Supporting information), and the detection limit (3s/k) [34] was as low as 3.58 nmol/L. These results show that probe NC7-AL has a rapid response and good detection sensitivity toward Au3+. We further investigated the selectivity profile of NC7-AL against other metal ions, such as Cu2+, Cu+, Ba2+, Mn2+, Ni2+, Pd2+, Ca2+, Cs+, Mg2+, Co2+, Ce3+, Cr3+, Na+, K+, Zn2+, Fe2+, Fe3+, Hg2+, Ag+, and Au+. The fluorescence intensity changes of the probe NC7AL upon addition of various other metal ions are shown in Fig. 2a. It can be seen that the fluorescence of NC7-AL showed no obvious changes after the addition of metal ions except Au3+ ions. Remarkably, commonly coexistent alkynophilic metal ions, such as Au+, Ag+, Pd2+, Ni2+, Cu2+, and Hg2+ have no interference on NC7AL. This is a notable advantage of NC7-AL compared to the existing probes for Au3+. As shown in Fig. 2b, bar graphs of NC7-AL toward various other metal ions (60 equivalent) both in the absence and presence of Au3+ (6 equivalent) were carried out to investigate the selectivity of NC7-AL to Au3+ in the presence of other metal ions. The fluorescence was activated when Au3+ ions were added to the solutions of NC7-AL and those metal ions, which indicated that the coexistence of other metal ions had little effect on the detection of
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142
Scheme 1. Synthetic route and possible Au3+-induced reaction mechanism of probe NC7-AL.
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
G Model
CCLET 3609 1–5 Q. Wang et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
3
Fig. 1. UV–vis absorption spectra (a) and emission spectra (b) of NC7-AL (5.0 mmol/L) in the presence of Au3+ (0–50.0 mmol/L) in CH3CN. Insets: images of NC7-AL solutions under (a) ambient light (b) UV 365 nm lamp, respectively, before (1) and after (2) treatment with Au3+ (50.0 mmol/L). Inset: the relationship between the fluorescence intensity (I420 nm) and the Au3+ concentrations.
Fig. 2. (a) Fluorescence spectra of NC7-AL (5 mmol/L) to Au3+ (6 equivalent) and other metal ions (60 equivalent) in CH3CN (lex = 360 nm). (b) Fluorescence intensity of NC7AL (5 mmol/L) to various metal ions (1–21: Au3+, Cu2+, Cu+, Ba2+, Mn2+, Ni2+, Pd2+, Ca2+, Cs+, Mg2+, Co2+, Ce3+, Cr3+, Na+, K+, Zn2+, Fe2+, Fe3+, Hg2+, Ag+, and Au+) in CH3CN. The black bars represent the emission of NC7-AL in the presence of various ions (60 equivalent). The red bars represent the emission that occurs upon subsequent addition of Au3+ Q6 (6 equivalent) to the solutions. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).
143 144
Au3+. As a result, NC7-AL could efficiently detect Au3+ ions in the mixture of other species.
145
3.3. The sensing mechanism
146 147
We propose that the carbon–carbon triple bond on the 3position of coumarin framework (a terminal ethynyl) in NC7-AL
could coordinate with Au3+, which initiates a cascade to generate the oxazolecarbaldehyde (NC7-CHO). This mechanism is widely acknowledged in the literature [22,24,25]. To further confirm the speculation (Scheme 1), the ESI-TOF mass spectra were used to study the reaction process of NC7-AL by Au3+. The peak of [NC7-AL + H]+ at m/z = 371.1396 was observed (Fig. 3a). When 6 equivalent of Au3+ was added to the solution, the peak at m/z = 385.1191 appeared,
Fig. 3. ESI-TOF mass spectra of (a) NC7-AL, and (b) NC7-AL + Au3+.
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
148 149 150 151 152 153 154
G Model
CCLET 3609 1–5 Q. Wang et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
4
Fig. 4. Photograph of the NC7-AL-based modified TLC plates toward various metal ions from left to right: NC7-AL, Au3+, Au+, Ag+, Hg2+, Cu2+, Pd2+, and Ni2+.
155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176
which unambiguously proved the formation of [NC7-CHO + H]+ (Fig. 3b). In addition, the carbon–carbon triple bond on the 7position of coumarin framework (an internal ethynyl) also had an affinity function with Au3+, which was confirmed by the divalent peak at m/z = 338.3411 corresponding to the [NC7-CHOAu(H2O)(CH3CN)Cl]2+ in Fig. 3b. To further demonstrate that Au3+ can coordinate with the internal ethynyl in probe NC7-AL, a certain amount of tetrabutylammonium cyanide (n-Bu4N+CN ) was added into the solution of NC7-AL pre-incubated with Au3+. The intense fluorescence immediately turned off (Fig. S3 in Supporting information), accompanying a distinctive color change from colorless to light yellow. The dramatic ‘‘on–off’’ response indicated that CN could sequester Au3+ from the complex NC7-AL-CHO-Au, and obtained free NC7-CHO. The result is in accordance with the blue-shift in the UV–vis absorption spectra of NC7-AL after addition of Au3+, and a similar mechanism has been reported by Emrullahog˘lu and co-workers [35]. In light of the above, we speculated that the high selectivity of NC7-AL to Au3+ can be attributed to not only the Au3+-induced intramolecular cyclization of terminal ethynyl in the probe, but also the strong affinity of Au3+ to the internal ethynyl in NC7-AL. We think it is of great value in the rational design of Au3+ probes with high selectivity.
177
3.4. Applications
178 179 180 181 182 183 184 185 186 187
Au3+ ions are widely used in various industrial processes and do extreme harm to humans. As such, easy and convenient testing methods for practical application are highly demanded. Therefore, we prepared the test strips by immersing TLC plates in the CH3CN solution of NC7-AL (10 mmol/L). Then we immersed the modified TLC plates into different metal ion solutions, and a distinct color change from light yellow to colorless was observed in the presence of Au3+, comparing to no color changes for the other metal ions (Fig. 4). Therefore, the NC7-AL-based modified TLC plates can conveniently detect Au3+ in solutions without any additional equipment.
188
4. Conclusion
189 190 191 192 193 194 195 196 197
In summary, a coumarin-based colorimetric and fluorescent probe (NC7-AL) for the detection of Au3+ ions was reported with a low detection limit, large Stokes shift, and rapid response. Probe NC7-AL exhibited a prominent ‘‘turn-on’’ fluorescent enhancement response only toward Au3+. High selectivity toward Au3+ was exhibited, and no cross-sensitivity was observed to other commonly coexistent alkynophilic metal ions. NC7-AL can detect Au3+ by the color change from light yellow to colorless without the use of any instrumentation.
198
Acknowledgment
199 Q3 This work was supported by the National Natural Science 200 Foundation of China (Nos. 21102001, 21271035 and 21372005),
Anhui Provincial Natural Science Foundation (No. 1608085MB39), Natural Science Foundation of Education Department of Anhui Province (Nos. KJ2015A047, KJ2014A013) and 211 Project of Anhui University. Q4
201 202 203 204
Appendix A. Supplementary data
205
Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.cclet.2016.02.021.
206 207
References
208
[1] J.C. Fierro-Gonzalez, B.C. Gates, Catalysis by gold dispersed on supports: the importance of cationic gold, Chem. Soc. Rev. 37 (2008) 2127–2134. [2] A.S.K. Hashmi, M. Rudolph, Gold catalysis in total synthesis, Chem. Soc. Rev. 37 (2008) 1766–1775. [3] D.H. Brown, W.E. Smith, The chemistry of the gold drugs used in the treatment of rheumatoid arthritis, Chem. Soc. Rev. 9 (1980) 217–240. [4] E.C. Dreaden, A.M. Alkilany, X.H. Huang, C.J. Murphy, M.A. El-Sayed, The golden age: gold nanoparticles for biomedicine, Chem. Soc. Rev. 41 (2012) 2740–2779. [5] R.A. Sperling, P.R. Gil, F. Zhang, M. Zanella, W.J. Parak, Biological applications of gold nanoparticles, Chem. Soc. Rev. 37 (2008) 1896–1908. [6] A. Arcadi, Alternative synthetic methods through new developments in catalysis by gold, Chem. Rev. 108 (2008) 3266–3325. [7] M. Rudolph, A.S.K. Hashmi, Gold catalysis in total synthesis—an update, Chem. Soc. Rev. 41 (2012) 2448–2462. [8] A.S.K. Hashmi, Gold-catalyzed organic reactions, Chem. Rev. 107 (2007) 3180–3211. [9] Z.G. Li, C. Brouwer, C. He, Gold-catalyzed organic transformations, Chem. Rev. 108 (2008) 3239–3265. [10] A. Corma, A. Leyva-Pe´rez, M.J. Sabater, Gold-catalyzed carbon-heteroatom bondforming reactions, Chem. Rev. 111 (2011) 1657–1712. [11] C.F. Shaw III, Gold-based therapeutic agents, Chem. Rev. 99 (1999) 2589–2600. [12] I. Ott, On the medicinal chemistry of gold complexes as anticancer drugs, Coord. Chem. Rev. 253 (2009) 1670–1681. [13] M. Navarro, Gold complexes as potential anti-parasitic agents, Coord. Chem. Rev. 253 (2009) 1619–1626. [14] W.D. Block, E.L. Knapp, Metabolism, toxicity, and manner of action of gold compounds in the treatment of arthritis VII. The effect of various gold compounds on the oxygen consumption of rat tissues, J. Pharmacol. Exp. Ther. 83 (1945) 275–278. [15] J.R.E. Jones, A further study of the relation between toxicity and solution pressure, with Polycelis nigra as test animal, J. Exp. Biol. 17 (1940) 408–415. [16] E.E. Connor, J. Mwamuka, A. Gole, C.J. Murphy, M.D. Wyatt, Gold nanoparticles are taken up by human cells but do not cause acute cytotoxicity, Small 1 (2005) 325–327. [17] C.M. Goodman, C.D. McCusker, T. Yilmaz, V.M. Rotello, Toxicity of gold nanoparticles functionalized with cationic and anionic side chains, Bioconjugate Chem. 15 (2004) 897–900. [18] A. Habib, M. Tabata, Oxidative DNA damage induced by HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl] ethanesulfonic acid) buffer in the presence of Au(III), J. Inorg. Biochem. 98 (2004) 1696–1702. [19] E. Nyarko, T. Hara, D.J. Grab, et al., In vitro toxicity of palladium(II) and gold(III) porphyrins and their aqueous metal ion counterparts on Trypanosoma brucei brucei growth, Chem. Biol. Interact. 148 (2004) 19–25. [20] J.F. Zhang, Y. Zhou, J. Yoon, J.S. Kim, Recent progress in fluorescent and colorimetric chemosensors for detection of precious metal ions (silver, gold and platinum ions), Chem. Soc. Rev. 40 (2011) 3416–3429. [21] S. Singha, D. Kim, H. Seo, S.W. Cho, K.H. Ahn, Fluorescence sensing systems for gold and silver species, Chem. Soc. Rev. 44 (2015) 4367–4399. [22] M.J. Jou, X.Q. Chen, K.M.K. Swamy, et al., Highly selective fluorescent probe for Au3+ based on cyclization of propargylamide, Chem. Commun. (2009) 7218–7220. Q5 ¨ c¸u¨ncu¨, A rhodamine based ‘‘turn-on’’ chemo[23] M. Emrullahog˘lu, E. Karakus¸a, M. U dosimeter for monitoring gold ions in synthetic samples and living cells, Analyst 138 (2013) 3638–3641. [24] O.A. Egorova, H. Seo, A. Chatterjee, K.H. Ahn, Reaction-based fluorescent sensing of Au(I)/Au(III) species: mechanistic implications on vinylgold intermediates, Org. Lett. 12 (2010) 401–403. [25] F.L. Song, H.F. Ning, H.Y. She, J.Y. Wang, X.J. Peng, A turn-on fluorescent probe for Au3+ based on rodamine derivative and its bioimaging application, Sci. China Chem. 57 (2014) 1043–1047. [26] H. Seo, M.E. Jun, O.A. Egorova, et al., A reaction-based sensing scheme for gold species: introduction of a (2-ethynyl) benzoate reactive moiety, Org. Lett. 14 (2012) 5062–5065. [27] N.T. Patil, V.S. Shinde, M.S. Thakare, et al., Exploiting the higher alkynophilicity of Au-species: development of a highly selective fluorescent probe for gold ions, Chem. Commun. 48 (2012) 11229–11231. [28] J.B. Wang, Q.Q. Wu, Y.Z. Min, Y.Z. Liub, Q.H. Song, A novel fluorescent probe for Au(III)/Au(I) ions based on an intramolecular hydroamination of a Bodipy derivative and its application to bioimaging, Chem. Commun. 48 (2012) 744–746. [29] P. Chinapang, V. Ruangpornvisuti, M. Sukwattanasinitt, P. Rashatasakhon, Ferrocenyl derivative of 1, 8-naphthalimide as a new turn-on fluorescent sensor for Au(III) ion, Dyes Pigment. 112 (2015) 236–238.
209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
G Model
CCLET 3609 1–5 Q. Wang et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
279 280 281 282 283 284 285
[30] J.H. Do, H.N. Kim, J. Yoon, J.S. Kim, H.J. Kim, A rationally designed fluorescence turn-on probe for the gold(III) ion, Org. Lett. 12 (2010) 932–934. [31] B.L. Wang, T. Fu, S. Yang, J.S. Li, Y. Chen, An intramolecular charge transfer (ICT)based dual emission fluorescent probe for the ratiometric detection of gold ions, Anal. Methods 5 (2013) 3639–3641. [32] M. Toumi, F. Couty, G. Evano, Total synthesis of paliurine F, Angew. Chem. Int. Ed. 46 (2007) 572–575.
5
[33] H.J. Yin, B.C. Zhang, H.Z. Yu, et al., Two-photon fluorescent probes for biological Mg2+ detection based on 7-substituted coumarin, J. Org. Chem. 80 (2015) 4306–4312. [34] S.Y. Lin, H.J. Zhu, W.J. Xu, G.M. Wang, N.Y. Fu, A squaraine based fluorescent probe for mercury ion via coordination induced deaggregation signaling, Chin. Chem. Lett. 25 (2014) 1291–1295. ¨ c¸u¨ncu¨, E. Karakus¸, M. Emrullahog˘lu, A ratiometric fluorescent probe for gold [35] M. U and mercury ions, Chem. Eur. J. 21 (2015) 13201–13205.
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
286 287 288 289 290 291 292
CCLET 3609 1–5 Chinese Chemical Letters xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Chinese Chemical Letters journal homepage: www.elsevier.com/locate/cclet 1 2 3 4
Original article
A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions
6
Wang, Yan Feng *, Jun Jiang, Wen-Juan Wang, Jiu-You Chen, Hong-Ting Sheng, Xiang-Ming Meng, Man-Zhou Zhu
7
School of Chemistry and Chemical Engineering & Center for Atomic Engineering of Advanced Materials, Anhui University, Hefei 230039, China
5
Q1 Qi
A R T I C L E I N F O
A B S T R A C T
Article history: Received 4 January 2016 Received in revised form 28 January 2016 Accepted 23 February 2016 Available online xxx
We develop a novel coumarin-alkyne derivative (NC7-AL), which can specifically react with Au3+ and give a colorimetric and fluorescent ‘‘turn-on’’ response toward Au3+. Notably, other alkynophilic metal species such as Au+, Ag+, Pd2+, Ni2+, Cu2+, and Hg2+ do not produce an interfering signal. A good linear relationship between emission intensity at 420 nm and Au3+ concentration from 0 to 2 equivalent is observed, and the detection limit (3s/k) is estimated to be ca. 3.58 nmol/L. Harnessing the Au3+-induced color change from light yellow to colorless, we find that NC7-AL-based modified TLC plate can be used for convenient naked-eye detection of Au3+. ß 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.
Keywords: Coumarin Alkyne Au3+ Colorimetric Fluorescent probe
8 9
1. Introduction
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
The noble metal gold (Au) and its salts have attracted intense attention owing to their potentials in catalysis [1,2] and biomedical applications [3–5]. Gold ions are known to activate alkynes for nucleophilic addition, and a series of organic transformations has been carried out according to the characteristic alkynophilicity of gold ions [6–10]. Also, gold-based drugs have been widely used in the treatment of rheumatoid arthritis and tuberculosis [11–13]. However, gold salts such as gold chloride are also highly toxic because they can damage the liver, kidneys, and nervous systems [14–16]. Furthermore, Au3+ ions have strong affinity to DNA, which could lead to the serious damage of DNA via the catalytic cleavage [17–19]. Therefore, it is highly desirable to develop effective methods for the specific, rapid, and real-time monitoring of Au3+ ions in the environment, agrochemicals, and potentially living systems. Fluorescence sensing has become a preferable approach for Au3+ detection because of its high sensitivity and selectivity, versatility, and ease of use [20,21]. Alkynes are often used as the recognition moiety for gold ions, due to their well-acknowledged alkynophilicity. Therefore, introducing a reactive alkyne moiety to the fluorophore could provide an efficient route to developing Au3+-selective fluorescent probes. Representative examples are Au3+-induced
Q2 * Corresponding author.
E-mail address: [email protected] (Y. Feng).
intramolecular cyclization of the rhodamine-based alkynes to yield oxazolecarbaldehyde derivatives [22–25]. Additionally, several alkyne-containing compounds as fluorescent probes for Au3+ ions based on fluorescein [26,27], BODIPY [28], 1,8-naphthalimide [29], and coumarin [30,31] fluorophores are also successfully designed and reported in the literature. However, the most prominent drawback of this sensing mechanism is the cross affinity with other alkynophilic metal species such as Au+, Ag+, Pd2+, Ni2+, Cu2+ and Hg2+, which interferes with the detection of Au3+ ions. Hence, there is an urgent need to develop a fluorescent probe for Au3+ free from the cross-sensitivity of other alkynophilic metal species. Herein, we present a colorimetric and fluorescent probe (NC7AL) for the detection of Au3+ utilizing the characteristic alkynophilicity of gold ions with low detection limit, large Stokes shift, and rapid response. Probe NC7-AL shows a remarkable fluorescence ‘‘turn-on’’ response only toward Au3+ ions over Au+, Ag+, Pd2+, Ni2+, Cu2+, and Hg2+. Upon addition of Au3+ ions, color changes from light yellow to colorless could be observed with the naked eye, and the NC7-AL-based modified TLC plates is an easy and convenient testing method that can be used for Au3+ detection.
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
2. Experimental
51
2.1. Materials and equipments
52
All solvents were purchased and dried according to standard procedures before use. 1H-NMR and 13C-NMR spectra were recorded
53 54
http://dx.doi.org/10.1016/j.cclet.2016.02.021 1001-8417/ß 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
G Model
CCLET 3609 1–5 Q. Wang et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
2
55 56 57 58 59 60 61
on a Bruker Avance II spectrometer at 400 MHz and 100 MHz, respectively. ESI-TOF spectra were recorded over a Waters xevo G2 QT mass spectrometer. UV–vis absorption spectra were recorded on a Shimadzu UV-1800 spectrophotometer. Fluorescence spectra were obtained using a Hitachi F-7000 Fluorescence spectrometer. The fluorescence quantum yields were measured with HORIBA FluoroMax-4P.
62 63
2.2. Synthesis of 7-((4-(dimethylamino)phenyl)ethynyl)-2-oxo-N(prop-2-yn-1-yl)-2H-chromene-3-carboxamide (NC7-AL)
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
A solution of NC7 (0.333 g, 1 mmol), 1-hydroxybenzotriazole (HOBT, 0.203 g, 1.5 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCHCl, 0.211 g, 1.1 mmol), ethyldiisopropylamine (DIPEA, 0.496 mL, 3 mmol), and propargylamine (0.192 mL, 3 mmol) in anhydrous DMF (10 mL) was stirred at r.t. under N2 atmosphere for 24 h. The crude product was extracted with CH2Cl2, washed with brine and purified by column chromatography on silica gel (CH2Cl2:petroleum ether = 1:1, v/v) to afford 0.136 g of NC7-AL as a yellow solid in a 37% yield. 1H NMR (400 MHz, DMSOd6): d 8.91 (t, 1H, J = 5.6 Hz), 8.87 (s, 1H), 7.98 (d, 1H, J = 8.1 Hz), 7.58 (s, 1H), 7.50 (d, 1H, J = 7.8 Hz), 7.42 (d, 2H, J = 8.6 Hz), 6.74 (d, 2H, J = 8.7 Hz), 4.13 (d, 2H, J = 3.2 Hz), 3.16 (s, 1H), 2.98 (s, 6H). 13C NMR (100 MHz, DMSO-d6): d 160.97, 160.08, 153.95, 150.60, 147.16, 132.94, 130.47, 128.92, 127.45, 118.06, 117.81, 117.52, 111.79, 107.12, 96.39, 86.99, 80.70, 73.26, 39.61, 28.70. HRMS (ESI-TOF): m/ z: calcd. For [C23H18N2O3 + H]+: 371.1317, found: 371.1396.
80
2.3. Preparation of test solution
81 82 83 84 85 86 87 88
In this paper, a solution of NC7-AL at 5 mmol/L in CH3CN was used for testing. The solutions of various testing species were prepared in doubly distilled water, and CH3CN-doubly distilled water (1:1, v/v) was used for Au3+ due to solubility problems. Various ions were prepared from AuCl, AuCl3, Ce(NO3)36H2O, Cs2CO3, NaCl, ZnCl2, NiSO46H2O, CrCl36H2O, CoCl2, MnCl24H2O, CaCl2, MgSO4, BaCl2, KCl, CuCl2, CuI, FeCl24H2O, FeCl3, AgNO3, HgCl2, PdCl2, and n-Bu4N+CN .
89
3. Results and discussion
90
3.1. Synthesis of probe NC7-AL
91 92 93 94 95
Compound NC7 was synthesized from salicylaldehyde following literature procedures [32,33]. Condensation of NC7 with propargylamine afforded NC7-AL as a yellow powder in a 37% yield (Scheme 1). The structure of NC7-AL was confirmed by 1H NMR, 13 C NMR, and HR-MS.
3.2. Spectroscopic properties
96
The UV–vis and fluorescence spectra of NC7-AL (5 mmol/L) were investigated in CH3CN. As shown in Fig. 1, the NC7-AL solution displayed almost no fluorescence. Addition of Au3+ to this solution resulted in enhancement of an emission band at 420 nm upon excitation at 360 nm. The emission intensity reached its maximum with ca. 6 equivalent of Au3+. An approximate 200-fold fluorescence enhancement could be observed accompanied by a quantum yield increase from <0.1% to 18.5%. The UV–vis spectra of NC7-AL displayed a similar sensing behavior toward the addition of Au3+. NC7-AL showed two absorption bands at 300 nm and 422 nm. With the addition of Au3+ (10 equivalent), the absorption band at 422 nm diminished, and a new absorption band with a maximum at 330 nm gradually increased. Concomitantly, the solution color changed from light yellow to colorless, facilitating direct observation by the naked eyes. A well-defined isosbestic point at 378 nm was found indicating a desired one-to-one type clean conversion. The Stokes shift was as large as 90 nm, which could minimize self-quenching. We studied the kinetics of the fluorescence enhancement resulting from the addition of Au3+ (6 equivalent) to the solution of probe NC7-AL. As shown in Fig. S1 in Supporting information, the fluorescence intensity reached its maximum in ca. 20 s. Thus, all testing of UV–vis absorption and fluorescence were performed after 1 min. Moreover, a good linear relationship between the dosage of Au3+ (from 0 to 2 equivalent) and the emission intensity was observed (Fig. S2 in Supporting information), and the detection limit (3s/k) [34] was as low as 3.58 nmol/L. These results show that probe NC7-AL has a rapid response and good detection sensitivity toward Au3+. We further investigated the selectivity profile of NC7-AL against other metal ions, such as Cu2+, Cu+, Ba2+, Mn2+, Ni2+, Pd2+, Ca2+, Cs+, Mg2+, Co2+, Ce3+, Cr3+, Na+, K+, Zn2+, Fe2+, Fe3+, Hg2+, Ag+, and Au+. The fluorescence intensity changes of the probe NC7AL upon addition of various other metal ions are shown in Fig. 2a. It can be seen that the fluorescence of NC7-AL showed no obvious changes after the addition of metal ions except Au3+ ions. Remarkably, commonly coexistent alkynophilic metal ions, such as Au+, Ag+, Pd2+, Ni2+, Cu2+, and Hg2+ have no interference on NC7AL. This is a notable advantage of NC7-AL compared to the existing probes for Au3+. As shown in Fig. 2b, bar graphs of NC7-AL toward various other metal ions (60 equivalent) both in the absence and presence of Au3+ (6 equivalent) were carried out to investigate the selectivity of NC7-AL to Au3+ in the presence of other metal ions. The fluorescence was activated when Au3+ ions were added to the solutions of NC7-AL and those metal ions, which indicated that the coexistence of other metal ions had little effect on the detection of
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142
Scheme 1. Synthetic route and possible Au3+-induced reaction mechanism of probe NC7-AL.
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
G Model
CCLET 3609 1–5 Q. Wang et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
3
Fig. 1. UV–vis absorption spectra (a) and emission spectra (b) of NC7-AL (5.0 mmol/L) in the presence of Au3+ (0–50.0 mmol/L) in CH3CN. Insets: images of NC7-AL solutions under (a) ambient light (b) UV 365 nm lamp, respectively, before (1) and after (2) treatment with Au3+ (50.0 mmol/L). Inset: the relationship between the fluorescence intensity (I420 nm) and the Au3+ concentrations.
Fig. 2. (a) Fluorescence spectra of NC7-AL (5 mmol/L) to Au3+ (6 equivalent) and other metal ions (60 equivalent) in CH3CN (lex = 360 nm). (b) Fluorescence intensity of NC7AL (5 mmol/L) to various metal ions (1–21: Au3+, Cu2+, Cu+, Ba2+, Mn2+, Ni2+, Pd2+, Ca2+, Cs+, Mg2+, Co2+, Ce3+, Cr3+, Na+, K+, Zn2+, Fe2+, Fe3+, Hg2+, Ag+, and Au+) in CH3CN. The black bars represent the emission of NC7-AL in the presence of various ions (60 equivalent). The red bars represent the emission that occurs upon subsequent addition of Au3+ Q6 (6 equivalent) to the solutions. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article).
143 144
Au3+. As a result, NC7-AL could efficiently detect Au3+ ions in the mixture of other species.
145
3.3. The sensing mechanism
146 147
We propose that the carbon–carbon triple bond on the 3position of coumarin framework (a terminal ethynyl) in NC7-AL
could coordinate with Au3+, which initiates a cascade to generate the oxazolecarbaldehyde (NC7-CHO). This mechanism is widely acknowledged in the literature [22,24,25]. To further confirm the speculation (Scheme 1), the ESI-TOF mass spectra were used to study the reaction process of NC7-AL by Au3+. The peak of [NC7-AL + H]+ at m/z = 371.1396 was observed (Fig. 3a). When 6 equivalent of Au3+ was added to the solution, the peak at m/z = 385.1191 appeared,
Fig. 3. ESI-TOF mass spectra of (a) NC7-AL, and (b) NC7-AL + Au3+.
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
148 149 150 151 152 153 154
G Model
CCLET 3609 1–5 Q. Wang et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
4
Fig. 4. Photograph of the NC7-AL-based modified TLC plates toward various metal ions from left to right: NC7-AL, Au3+, Au+, Ag+, Hg2+, Cu2+, Pd2+, and Ni2+.
155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176
which unambiguously proved the formation of [NC7-CHO + H]+ (Fig. 3b). In addition, the carbon–carbon triple bond on the 7position of coumarin framework (an internal ethynyl) also had an affinity function with Au3+, which was confirmed by the divalent peak at m/z = 338.3411 corresponding to the [NC7-CHOAu(H2O)(CH3CN)Cl]2+ in Fig. 3b. To further demonstrate that Au3+ can coordinate with the internal ethynyl in probe NC7-AL, a certain amount of tetrabutylammonium cyanide (n-Bu4N+CN ) was added into the solution of NC7-AL pre-incubated with Au3+. The intense fluorescence immediately turned off (Fig. S3 in Supporting information), accompanying a distinctive color change from colorless to light yellow. The dramatic ‘‘on–off’’ response indicated that CN could sequester Au3+ from the complex NC7-AL-CHO-Au, and obtained free NC7-CHO. The result is in accordance with the blue-shift in the UV–vis absorption spectra of NC7-AL after addition of Au3+, and a similar mechanism has been reported by Emrullahog˘lu and co-workers [35]. In light of the above, we speculated that the high selectivity of NC7-AL to Au3+ can be attributed to not only the Au3+-induced intramolecular cyclization of terminal ethynyl in the probe, but also the strong affinity of Au3+ to the internal ethynyl in NC7-AL. We think it is of great value in the rational design of Au3+ probes with high selectivity.
177
3.4. Applications
178 179 180 181 182 183 184 185 186 187
Au3+ ions are widely used in various industrial processes and do extreme harm to humans. As such, easy and convenient testing methods for practical application are highly demanded. Therefore, we prepared the test strips by immersing TLC plates in the CH3CN solution of NC7-AL (10 mmol/L). Then we immersed the modified TLC plates into different metal ion solutions, and a distinct color change from light yellow to colorless was observed in the presence of Au3+, comparing to no color changes for the other metal ions (Fig. 4). Therefore, the NC7-AL-based modified TLC plates can conveniently detect Au3+ in solutions without any additional equipment.
188
4. Conclusion
189 190 191 192 193 194 195 196 197
In summary, a coumarin-based colorimetric and fluorescent probe (NC7-AL) for the detection of Au3+ ions was reported with a low detection limit, large Stokes shift, and rapid response. Probe NC7-AL exhibited a prominent ‘‘turn-on’’ fluorescent enhancement response only toward Au3+. High selectivity toward Au3+ was exhibited, and no cross-sensitivity was observed to other commonly coexistent alkynophilic metal ions. NC7-AL can detect Au3+ by the color change from light yellow to colorless without the use of any instrumentation.
198
Acknowledgment
199 Q3 This work was supported by the National Natural Science 200 Foundation of China (Nos. 21102001, 21271035 and 21372005),
Anhui Provincial Natural Science Foundation (No. 1608085MB39), Natural Science Foundation of Education Department of Anhui Province (Nos. KJ2015A047, KJ2014A013) and 211 Project of Anhui University. Q4
201 202 203 204
Appendix A. Supplementary data
205
Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.cclet.2016.02.021.
206 207
References
208
[1] J.C. Fierro-Gonzalez, B.C. Gates, Catalysis by gold dispersed on supports: the importance of cationic gold, Chem. Soc. Rev. 37 (2008) 2127–2134. [2] A.S.K. Hashmi, M. Rudolph, Gold catalysis in total synthesis, Chem. Soc. Rev. 37 (2008) 1766–1775. [3] D.H. Brown, W.E. Smith, The chemistry of the gold drugs used in the treatment of rheumatoid arthritis, Chem. Soc. Rev. 9 (1980) 217–240. [4] E.C. Dreaden, A.M. Alkilany, X.H. Huang, C.J. Murphy, M.A. El-Sayed, The golden age: gold nanoparticles for biomedicine, Chem. Soc. Rev. 41 (2012) 2740–2779. [5] R.A. Sperling, P.R. Gil, F. Zhang, M. Zanella, W.J. Parak, Biological applications of gold nanoparticles, Chem. Soc. Rev. 37 (2008) 1896–1908. [6] A. Arcadi, Alternative synthetic methods through new developments in catalysis by gold, Chem. Rev. 108 (2008) 3266–3325. [7] M. Rudolph, A.S.K. Hashmi, Gold catalysis in total synthesis—an update, Chem. Soc. Rev. 41 (2012) 2448–2462. [8] A.S.K. Hashmi, Gold-catalyzed organic reactions, Chem. Rev. 107 (2007) 3180–3211. [9] Z.G. Li, C. Brouwer, C. He, Gold-catalyzed organic transformations, Chem. Rev. 108 (2008) 3239–3265. [10] A. Corma, A. Leyva-Pe´rez, M.J. Sabater, Gold-catalyzed carbon-heteroatom bondforming reactions, Chem. Rev. 111 (2011) 1657–1712. [11] C.F. Shaw III, Gold-based therapeutic agents, Chem. Rev. 99 (1999) 2589–2600. [12] I. Ott, On the medicinal chemistry of gold complexes as anticancer drugs, Coord. Chem. Rev. 253 (2009) 1670–1681. [13] M. Navarro, Gold complexes as potential anti-parasitic agents, Coord. Chem. Rev. 253 (2009) 1619–1626. [14] W.D. Block, E.L. Knapp, Metabolism, toxicity, and manner of action of gold compounds in the treatment of arthritis VII. The effect of various gold compounds on the oxygen consumption of rat tissues, J. Pharmacol. Exp. Ther. 83 (1945) 275–278. [15] J.R.E. Jones, A further study of the relation between toxicity and solution pressure, with Polycelis nigra as test animal, J. Exp. Biol. 17 (1940) 408–415. [16] E.E. Connor, J. Mwamuka, A. Gole, C.J. Murphy, M.D. Wyatt, Gold nanoparticles are taken up by human cells but do not cause acute cytotoxicity, Small 1 (2005) 325–327. [17] C.M. Goodman, C.D. McCusker, T. Yilmaz, V.M. Rotello, Toxicity of gold nanoparticles functionalized with cationic and anionic side chains, Bioconjugate Chem. 15 (2004) 897–900. [18] A. Habib, M. Tabata, Oxidative DNA damage induced by HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl] ethanesulfonic acid) buffer in the presence of Au(III), J. Inorg. Biochem. 98 (2004) 1696–1702. [19] E. Nyarko, T. Hara, D.J. Grab, et al., In vitro toxicity of palladium(II) and gold(III) porphyrins and their aqueous metal ion counterparts on Trypanosoma brucei brucei growth, Chem. Biol. Interact. 148 (2004) 19–25. [20] J.F. Zhang, Y. Zhou, J. Yoon, J.S. Kim, Recent progress in fluorescent and colorimetric chemosensors for detection of precious metal ions (silver, gold and platinum ions), Chem. Soc. Rev. 40 (2011) 3416–3429. [21] S. Singha, D. Kim, H. Seo, S.W. Cho, K.H. Ahn, Fluorescence sensing systems for gold and silver species, Chem. Soc. Rev. 44 (2015) 4367–4399. [22] M.J. Jou, X.Q. Chen, K.M.K. Swamy, et al., Highly selective fluorescent probe for Au3+ based on cyclization of propargylamide, Chem. Commun. (2009) 7218–7220. Q5 ¨ c¸u¨ncu¨, A rhodamine based ‘‘turn-on’’ chemo[23] M. Emrullahog˘lu, E. Karakus¸a, M. U dosimeter for monitoring gold ions in synthetic samples and living cells, Analyst 138 (2013) 3638–3641. [24] O.A. Egorova, H. Seo, A. Chatterjee, K.H. Ahn, Reaction-based fluorescent sensing of Au(I)/Au(III) species: mechanistic implications on vinylgold intermediates, Org. Lett. 12 (2010) 401–403. [25] F.L. Song, H.F. Ning, H.Y. She, J.Y. Wang, X.J. Peng, A turn-on fluorescent probe for Au3+ based on rodamine derivative and its bioimaging application, Sci. China Chem. 57 (2014) 1043–1047. [26] H. Seo, M.E. Jun, O.A. Egorova, et al., A reaction-based sensing scheme for gold species: introduction of a (2-ethynyl) benzoate reactive moiety, Org. Lett. 14 (2012) 5062–5065. [27] N.T. Patil, V.S. Shinde, M.S. Thakare, et al., Exploiting the higher alkynophilicity of Au-species: development of a highly selective fluorescent probe for gold ions, Chem. Commun. 48 (2012) 11229–11231. [28] J.B. Wang, Q.Q. Wu, Y.Z. Min, Y.Z. Liub, Q.H. Song, A novel fluorescent probe for Au(III)/Au(I) ions based on an intramolecular hydroamination of a Bodipy derivative and its application to bioimaging, Chem. Commun. 48 (2012) 744–746. [29] P. Chinapang, V. Ruangpornvisuti, M. Sukwattanasinitt, P. Rashatasakhon, Ferrocenyl derivative of 1, 8-naphthalimide as a new turn-on fluorescent sensor for Au(III) ion, Dyes Pigment. 112 (2015) 236–238.
209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
G Model
CCLET 3609 1–5 Q. Wang et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
279 280 281 282 283 284 285
[30] J.H. Do, H.N. Kim, J. Yoon, J.S. Kim, H.J. Kim, A rationally designed fluorescence turn-on probe for the gold(III) ion, Org. Lett. 12 (2010) 932–934. [31] B.L. Wang, T. Fu, S. Yang, J.S. Li, Y. Chen, An intramolecular charge transfer (ICT)based dual emission fluorescent probe for the ratiometric detection of gold ions, Anal. Methods 5 (2013) 3639–3641. [32] M. Toumi, F. Couty, G. Evano, Total synthesis of paliurine F, Angew. Chem. Int. Ed. 46 (2007) 572–575.
5
[33] H.J. Yin, B.C. Zhang, H.Z. Yu, et al., Two-photon fluorescent probes for biological Mg2+ detection based on 7-substituted coumarin, J. Org. Chem. 80 (2015) 4306–4312. [34] S.Y. Lin, H.J. Zhu, W.J. Xu, G.M. Wang, N.Y. Fu, A squaraine based fluorescent probe for mercury ion via coordination induced deaggregation signaling, Chin. Chem. Lett. 25 (2014) 1291–1295. ¨ c¸u¨ncu¨, E. Karakus¸, M. Emrullahog˘lu, A ratiometric fluorescent probe for gold [35] M. U and mercury ions, Chem. Eur. J. 21 (2015) 13201–13205.
Please cite this article in press as: Q. Wang, et al., A coumarin-based colorimetric and fluorescent probe for the highly selective detection of Au3+ ions, Chin. Chem. Lett. (2016), http://dx.doi.org/10.1016/j.cclet.2016.02.021
286 287 288 289 290 291 292