Highly Specific and Reversible Fluoride Sensor Based on an Organic

Article pubs.acs.org/ac

Highly Specific and Reversible Fluoride Sensor Based on an Organic Semiconductor Hecham Aboubakr,† Hugues Brisset,*,‡ Olivier Siri,† and Jean-Manuel Raimundo*,† †

Centre Interdisciplinaire de Nanoscience de Marseille (CINaM-UMR CNRS 7325), Aix-Marseille Université, 163 Ave de Luminy Case 913, 13288 Marseille Cedex 09, France ‡ Laboratoire Matériaux Polymères-Interfaces-Environnement Marin (MAPIEM), Université de Toulon, EA 4323, 83957 La Garde, France S Supporting Information *

ABSTRACT: A novel sulfonamide-conjugated benzo-[2,1b:3,4-b′]bithiophene semiconductor has been designed and synthetized in order to develop a probe for specific detection of anions both in the homogeneous (solution) and heterogeneous phase. Its photophysical and electrochemical data were reported in this study. On the basis of the optical and NMR titrations analysis, the chelator was found to be highly selective for fluoride compared to others anions (Ka = 1.6 × 104 M−1 in dimethyl sulfoxide (DMSO)). In addition, from an intricate sample, the novel chelator shows exceptional specificity toward fluoride and reveals a complete reversibility after addition of trifluoroacetic acid (TFA). Sensing films were obtained by electrochemical polymerization of the probe on an electrode surface, which clearly show effective detection of fluoride. broaden the scope of the field. Among the heteroaromatic structures, the fused bithiophene core has been widely used in the design of chromophores for optoelectronics applications due to their ability of electropolymerization.21

A

nions are ubiquitous in many physiological and enzymatic processes in life,1 and their possible disruptions may cause adverse effects.2,3 Furthermore, anthropogenic activities (mainly industries and agriculture) also contribute to an increase of the anions concentration in soils and in water, including introduction of new anionic species in the ecosystems causing therefore some ecological dysfunctionalities.4 For all these reasons, there is a crucial need to develop systems that are suitable for anions sensing within such biomedical and environmental concerns. During the last 2 decades, the design synthesis of artificial hosts for anion recognition received significant interest and has become an important area of research in supramolecular chemistry.5 Host−guest interactions in anions receptors are based mostly on noncovalent interaction and used for anion sensing purposes.6 Those include electrostatic interactions, hydrogen bonding, hydrophobicity, and coordination to a metal ion as well as a combination of these interactions. The receptors can be positively charged, containing binding sites such as pyridinium, polyammonium, and quaternary ammonium groups.7,8 They can also be neutral containing amide,9−11 urea, thiourea,12 sulfonamides,13 or pyrroles14 functions in calix[4]arenes and porphyrins.15 Among these receptors, sulfonamides are of particular interest because they showed a remarkable selectivity to fluorine anions. Our interest in both sensitive sensors based on electrical/ optical properties16−18 and small bandgap organic semiconductors19,20 led us to combine their properties to possibly © 2013 American Chemical Society

Curiously, these bithiophenes have been only recently used in the design of cation sensor22 but are still unexplored as anion sensor, whereas their electrochemical properties render them ideally suited for a detection based on an electrochemical signal output. We report herein the synthesis and characterization of the first fused bithiophene core containing a bis-sulfonamidequinoxaline moiety possessing significant sensing properties to fluoride with a high selectivity and unprecedented specificity in solution. Its subsequent electropolymerization on an electrode allows detection of fluoride in the heterogeneous phase.

■

EXPERIMENTAL SECTION Reagents and Analysis. Ethanol, methylene chloride, toluene, and dimethyl sulfoxide (DMSO) were purchased from

Received: September 3, 2013 Accepted: September 18, 2013 Published: September 18, 2013 9968

dx.doi.org/10.1021/ac4027934 | Anal. Chem. 2013, 85, 9968−9974

Analytical Chemistry

Article

CarloErba. F−, Cl−, Br−, I−, H2PO4−, ClO4−, CH3CO2−, and HSO4− as tetrabutylamonium salts were purchased from Fluka. Nitrobenzene and trifluoroacetic acid (TFA) were purchased from Sigma-Aldrich. Physicochemical Analyses. The melting point is uncorrected and was obtained from an Electrothermal 9100 apparatus. 1H and 13C NMR spectra were recorded on Bruker AC 250 at 250 and 62.5 MHz, respectively. High-resolution mass spectrometry was performed with a Qstar Elite spectrometer (Applied Biosystems SCIEX) with an electrospray ionization source (ESI). Elemental analysis was recorded with an EA 1112 series from ThermoFinnigan. XR diffraction (λMoKα = 0.710 73 Å) under a monocrystal was made with a Bruker-Nonius spectrometer.23 Physicochemical Measurements in Solution. UV− visible absorption spectra were obtained on a Varian Cary 1E spectrophotometer. The electronic absorption maxima (λmax) are directly extracted from absorption spectra of chelator 3 based solution. Under the optimum conditions, the stoichiometry between chelator 3 and the different analytes were investigated by the molar ratio method24 in both UV−visible and 1H NMR techniques. Cyclic voltammetry (CV) data were acquired using a BAS 100 potentiostat (Bioanalytical Systems) and a PC computer containing BAS100W software (v2.3). A three-electrode system based on a platinum (Pt) working electrode (diameter 1.6 mm), a Pt counter electrode, and an Ag/AgCl (with 3 M NaCl filling solution) reference electrode was used. Tetrabutylammonium hexafluorophosphate (n-Bu4NPF6) (Fluka) was used as received and served as the supporting electrolyte (0.1 M). All experiments were carried out in anhydrous nitrobenzene (electronic grade purity) at 20 °C. The electrochemical oxidation potential value vs Ag/AgCl is determined from the cyclic voltammogram at a concentration of 1 × 10−3 M with a scan rate of 100 mV s−1. Electropolymerization of 3 was performed in nitrobenzene at 1 × 10−2 M with n-Bu4NPF6 as the electrolyte salt and the response of polymer in acetonitrile with n-Bu4NPF6 at 0.1 M with a scan rate of 100 mV s−1. Synthesis of Benzo[2,1-b:3,4-b′]dithiophene-4,5-(quinoxaline-6,7-diyl)bis(4-toluenesulfonamide), 3. A mixture of 0.3 g (1.36 mmol) of diketone 125,26 and 0.6 g (1.35 mmol) of 1,2-diamino-4,5-bis(toluenesulfonamido)benzene 227 in 25 mL of ethanol/acetic acid (v:v ; 20:5) solution are refluxed for 2 h. After cooling, the obtained solid was isolated by filtration and washed with ethanol affording 0.58 g (68% yield) of title compound as an orange solid. Mp = 176−178 °C. 1H NMR (250 MHz, DMSO-d 6 , Figure S1 in the Supporting Information) δ: 2.34 (s, 6H, 2× Ar−CH3); 7.39 (d, 4H, 3J = 8.2 Hz, 4× Hphe); 7.78 (d, 4H, 3J = 8.4 Hz, 4× Hphe); 7.88 (d, 2H, 3J = 5.2 Hz, 2× Hthio); 7.91 (s, 2H, 2× H−CHC− NH−); 8.22 (d, 2H, 3J = 5.4 Hz, 2× Hthio); 10.2 (s, 2H, 2× NH). 13C NMR (62.5 MHz, DMSO-d6, Figure S2 in the Supporting Information) δ: 21.2 (2× CH3); 124.7 (2× Cthio); 126.6 (2× Cphe); 127.2 (4× CHphe); 130.2 (4× CHphe); 132.8 (2× CHthio); 134.2 (2× CHthio); 135.2 (2× Cphe); 136.3 (2× Cphe); 138.6 (CHphe); 139.0 (Cphe); 144.3 (Cphe). MS (ESI+) m/z: 631.0597 [M + H]+; calculated for [M + H]+: 631.0597. Elemental analysis for C30H22O4S4N4 (%): calculated C, 57.12; H, 3.52; S, 20.33; N, 8.88. Found C, 57.13; H, 3.70; S, 20.42; N, 8.61. Yellow crystals of 3 were obtained by slow diffusion of a CH2Cl2 solution, with the triclinic space group P-1 with a = 9.6443(2), b = 9.9680(3), c = 15.3462(5), α = 104.446 (1)°, β

= 91.379 (1)°, γ = 96.793 (1)° at 293(2) K with Z = 2, and V = 1416.42(7) Å3. The refinement of 7004 reflections and 379 parameters yielded R1 = 0.0684 for all data (4288 reflections with I > 2σ(I)) (see the Supporting Information). Atomic coordinates, bond lengths and angles, and thermal parameters for 3 have been deposited at the Cambridge Crystallographic Data Centre (No. CCDC-900835). Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, U.K. E-mail: [email protected].

■

RESULTS AND DISCUSSION The synthesis of the chelator 3 is outlined in Scheme 1. Molecule 3 was readily obtained from the cross coupling Scheme 1. Synthesis of the Chelator 3

reaction of the benzo[2,1-b:3,4-b′]dithiophene-4,5-dione 125,26 core with the 1,2-diamino-4,5-bis(toluenesulfonamido)-benzene 2 in 75% yield. 2 was prepared according to reported procedures27 from 1,2-phenylenediamine in three steps affording the target compound in 67% overall yield. The optical properties, absorption and fluorescence emission, of the receptor 3 were studied in DMSO28 solution (Figure 1).

Figure 1. Absorption (solid line) and emission (dotted line) spectra of 3 in DMSO.

UV−visible absorption spectrum of 3 exhibits several bands29 centered at 303, 413, and 463 nm corresponding to (i) the absorption of the aromatic sulfonamides units, (ii) the extensive π-conjugated system, and (iii) a charge transfer band, respectively.13h A broad band at 587 nm highlighting a large Stokes shift of 284 nm characterizes the emission spectrum of 3 obtained by excitation at 303 nm. Then, the anion binding properties of receptor 3 was first investigated by UV−visible spectroscopy with several anions (F−, Cl−, Br−, I−, H2PO4−, ClO4−, CH3CO2−, or HSO4−) (Figure 2 and Figure S4 in the Supporting Information). Interestingly, even in polar solvents, 9969



Article

presence of the anions (Figure S5 in the Supporting Information). Consequently, no further studies have been pursued by fluorescence spectroscopy. Nevertheless, in order to get further insights on the binding ability of 3 and refine the previous Hofmeister series, proton NMR titration experiments were performed in deuterated DMSO-d6 solutions. Again the formation of [1 + 1] complexes 3·X− is clearly observed by varying the number equivalents of each anion. Indeed, aromatic protons signals of the sulfonamide (for instance Ha at 7.91 ppm and Hc at 7.39 ppm) shift progressively upfield and are preeminent upon addition of 1 equiv of X− (Figures 4 and 5). No further shift is observed even

Figure 3. Crystal structure of the chelator 3 (S, yellow; O, red; C, gray; N, violet; H, blue).

Figure 2. Optical variations of 3 in DMSO upon addition of (a) fluoride and (b) perchlorate anion.

such as DMSO, compound 3 interacts with these putative anionic guests, emphasizing differents degrees of spectroscopic changes which depend on the nature of the anion and its basicity. The binding of the anion with 3 results in a change of the absorption properties mainly at 413 and 463 nm associated with hypochromic and hyperchromic effects, respectively. The amplitude of the optical variations as well as the appearance of an isosbestic point is ascribed to the ability of 3 to interact more or less specifically through an equilibrium process with a given anion. No further absorption changes were noticed after addition of excess anion. The Job plots suggest the formation of [1 + 1] complexes 3·X− in agreement with results reported previously in literature on similar systems.13,30 Moreover, the observed minor changes in absorption upon addition of anions imply only a hydrogen-bonding interaction which was further confirmed by 1H NMR titration experiments (vide infra). The most insignificant spectral alterations were obtained with chloride, perchlorate, bromide, iodide, and bisulfate anions (Figure S4 in the Supporting Information) while major changes are observed with F−, H2PO4−, and CH3CO2−. On the basis of these results, a first approximate Hofmeister series can be settled as follow: F− ≈ H2PO4− ≈ CH3CO2− ≫ I− ≈ HSO4− ≈ Br− ≫ Cl− ≈ ClO4−.31 Because of the fluorescent properties of compound 3 (Figure 1), titration experiments have been also followed by emission spectroscopy. As unexpected, trivial fluorescent changes were observed in most cases and no linear dependence of the light absorbed has been found even at low concentration in the

Figure 4. Interactions of the sulfonamide part with anions.

if an excess of anion was added. Furthermore, as shown in the 1 H NMR of 3 (Figure 5), the two Ha protons in solution are isochronous and resonate at the same frequency due to an

Figure 5. 1H aromatic region of 3 upon addition of 0.1−1.4 equiv of F− anions as tetrabutylammonium salts in DMSO-d6 (step of 0.1 equiv). 9970



Article

identical chemical environment. This observation is consistent with the existence of only one singlet, highlighting a symmetrical molecule in solution unlike the solid state according to the X-ray structure of 3 (Figure 3). Examination of the noncovalent intramolecular interactions from the X-ray structure of 3 reveals the presence of H-bonds between the oxygen (O4) atom of the SO2 group and the C−H3 proton (d(C−H···O2S) = 2.428 Å) suggesting that these interactions may also exist in solution and could explain the symmetry of 3. As a consequence, the two NH might be oriented in the same direction allowing easy access of guest analytes. This hypothesis is also supported by the fact that the symmetry remains unchanged even after analyte binding (i.e., formation of 3·F−). It is noteworthy that in all cases, neither additional shifting or new signal (for instance HF2− in the case of fluoride (Figure S6 in the Supporting Information)) was observed after addition of excess anion. These features are fully in agreement with a hydrogen-bonding interaction between the analyte and the probe due to the weaker acidity of the N−H protons compared to others systems reported in the literature (Figure 4).13g It should also be noted here that we were not able to follow the N−H signal due to its broadening (rapid proton exchange occurs owing the presence of a trace amount of water in DMSO-d6) (Figure S6 in the Supporting Information). The selectivity of 3 was then investigated. As shown in Figure 6, 1H NMR chemical shifts are compared upon addition of 1

Table 1. Association Constants Determined in DMSO for the Host−Guest Complexes 3·X− −

F H2PO4− CH3CO2− I− Br− HSO4− Cl− ClO4−

Ka × 104 M−1 (UV−vis)

Ka × 104 M−1 (RMN)33

1.6 1.1 0.9 0.067 0.058 0.0036 0.0023 0.0016

52.2 6.72 0.15 0.15 0.20 0.25 0.34 0.26

roughly similar compared to analogous chelators reported in the literature.17 Moreover, with the aim to develop reliable sensors, the reversibility and specificity of the probe 3 are key events that have to be determined. Curiously, such parameters are often missing in the literature. Basic studies in these directions have been successfully carried out. First of all, the reversibility of the process has been investigated by UV−vis spectroscopy (Figure 7a and Figure S7 in the Supporting Information) and proton NMR (Figure 7b and Figure S8 in the Supporting Information) experiments upon gradual addition of trifluoroacetic acid (TFA) to the host−guest complex 3·F−. It was clearly shown that addition of 1 equiv of trifluoroacetic acid to the complex is needed to go back to the initial spectrum of uncomplexed 3. Subsequent addition of 1 equiv of anions afforded once again

Figure 6. 1H aromatic region of 3 upon addition of 1 equiv of F−, Cl−, Br − , I − , H 2 PO 4 − , ClO 4 − , CH 3 CO 2 − , or HSO 4 − anions as tetrabutylammonium salts in DMSO-d6.

equiv of each anion to receptor 3. The aromatic protons Ha are shifted slightly upfield upon addition of 1 equiv of anions in all case but with different degrees. On the basis of these experiments, it is unequivocally confirmed that the highest observed effect is de novo achieved for F− and the lowest for Cl−. Thus, a more relevant and accurate Hofmeister series could be deduced from these experiments compared to that obtained previously: F− ≫ H2PO4− ≫ CH3CO2− ≈ I− > Br− > HSO4− > ClO4− ≈ Cl−. From both UV−vis and 1H NMR spectroscopies, association constants could be determined using the Benesi−Hildebrand and Scott methods, respectively (Table 1).32 Accordingly, it was clearly shown that the chelator 3 possess the higher selectivity toward fluoride with Ka = 1.6 × 104 M−1 (UV−visible) which is

Figure 7. Reversibility studies of 3 to fluorine anion based on (a) UV− vis absorption in DMSO and (b) proton NMR in DMSO-d6 experiments. 9971



Article

the host−guest complex 3·F− demonstrating undoubtedly the clear reversibility of our chelator. Repeating such a process several times led to the same behavior. Importantly, an additional remarkable feature of probe 3 was pinpointed, its ability to specifically recognize fluoride in an admixture of anions. Indeed, selectivity or specificity could be amended due to concomitant competition of the different anions present in solution. Interestingly, as evidenced by proton NMR, the obtained spectrum in the presence of the anions mixture (Figure 8b) appears to be the footprint of the

Figure 8. 1H aromatic region of 3 upon addition: (a) of 1 equiv of F− and (b) of a mixture with 1 equiv of each F−, Cl−, Br−, I−, H2PO4−, ClO4−, CH3CO2−, or HSO4− anions as tetrabutylammonium salts in DMSO-d6.

spectrum of 3·F − tested with F − alone (Figure 8a). Unambiguously, this behavior illuminates the selectivity and specificity of the probe 3 to the fluorine anions even if competitive anions are present. Electrochemical behavior of 3 was also investigated by cyclic voltammetry in nitrobenzene with n-Bu4NPF6 (0.1 M) as the supporting electrolyte. The aim of this study was to yield, on an electrode surface, a sensitive solid-state electrogenerated electrochemical sensor from probe 3 (i.e., modified electrode based on 3). The cyclic voltammogram versus Ag/AgCl is depicted in Figure 9a. During the anodic scan, 3 exhibits one oxidation peak at 1.08 V ascribed to the radical cation formation of the dithienylbenzene system.34 Monomer 3 is soluble only in DMSO or nitrobenzene and was then subjected to an electrochemical polymerization. Although very low thick film formation on the electrode surface was observed via repetitive cycling or a prolonged anodic electrolysis (due to the low solubility of the oligomeric species in the electrolyte solution (Figure 9b), a polymer response has been obtained from the deposited film (Figure 9c and Figure S9 in the Supporting Information). This observation clearly demonstrates the formation of an electrogenerated conducting polymer (poly3), bearing specific chelating groups to fluoride, on the electrode surface. This unique combination of properties (detection plus electropolymerization) for the probe 3 makes it a system of choice for the design and development of new selective and specific sensors based on an electrochemical signal ouput. Upon addition of 1 equiv of fluoride, the binding of the analyte to the electrogenerated polymer (poly3) leads to a reversible redox process which is negatively shifted by 24 mV from the modified electrode (Figure 9c, red curve).

Figure 9. (a) Cyclic voltammogram, (b) electropolymerization of chelator 3 at 10−2 M in nitrobenzene, n-Bu4NPF6 (0.1 M) scan rate 100 mV s−1. (c) Response of poly(3) in n-Bu4NPF6 (0.1 M)/CH3CN without (black) and with F− anion (red) as tetrabutylammonium salt, scan rate 100 mV s−1.

sensitivity and specificity toward fluoride over other anions. In addition, the reversible binding properties of 3, a crucial key point for the development of regenerable sensors, was clearly highlighted. Finally, the formation of an electrogenerated polymer on an electrode surface based on the monomer 3 became attainable, associated with efficient electrochemical sensing properties to fluoride. This unique combination of properties makes this probe a system of choice for the foreseen

■

CONCLUSION In summary, we reported herein the synthesis and characterization of a novel organic semiconductor possessing remarkable 9972



Article

7788. (e) Wu, Y.; Peng, X.; Fan, J.; Gao, S.; Tian, M.; Zhao, J.; Sun, S. J. Org. Chem. 2007, 72, 62−70. (f) Lin, T.-P.; Chen, C.-Y.; Wen, Y.-S.; Sun, S.-S. Inorg. Chem. 2007, 46, 9201−9212. (g) Bhosale, S. V.; Kalyankar, M. B.; Langford, S. J. Org. Lett. 2009, 11, 5418−5421. (h) El-Ballouli, A. O.; Zhang, Y.; Barlow, S.; Marder, S. R.; Al-Sayah, M. H.; Kaafarani, B. R. Tetrahedron Lett. 2012, 53, 661−665. (14) (a) Cho, W. S.; Sessler, J. L. In Artificial Pyrrole-Based Anion Receptors in Functional Synthetic Receptors; Schrader, T., Hamilton, A. D., Eds.; Wiley-VCH: Weinheim, Germany, 2005; Chapter 4, p 165. (b) Dydio, P.; Lichosyt, D.; Jurczak, J. Chem. Soc. Rev. 2011, 40, 2971− 2985. (15) (a) Joseph, R.; Pulla Rao, C. Chem. Rev. 2011, 111, 4658−4702. (b) Brown, A.; Beer, P. D. Dalton Trans 2012, 41, 118−129 and references therein. (16) (a) Navarro, A.-E.; Spinelli, N.; Chaix, C.; Moustrou, C.; Mandrand, B.; Brisset, H. Bioorg. Med. Chem. Lett. 2004, 14, 2439− 2441. (b) Navarro, A.-E.; Spinelli, N.; Moustrou, C.; Chaix, C.; Mandrand, B.; Brisset, H. Nucleic Acids Res. 2004, 32 (17), 5310− 5319. (c) Navarro, A.-E.; Fages, F.; Moustrou, C.; Brisset, H.; Spinelli, N.; Chaix, C.; Mandrand, B. Tetrahedron 2005, 61, 3947−3952. (d) Brisset, H.; Navarro, A.-E.; Spinelli, N.; Chaix, C.; Mandrand, B. Biotechnol. J. 2006, 1, 95−98. (17) (a) Moggia, F.; Brisset, H.; Fages, F.; Chaix, C.; Mandrand, B.; Dias, M.; Levillain, E. Tetrahedron. Lett. 2006, 47, 3371−3374. (b) Moggia, F.; Brisset, H.; Fages, F.; Blanchard, P.; Roncali, J. Electrochem. Commun. 2006, 8, 533−538. (c) Moggia, F.; Fages, F.; Brisset, H.; Chaix, C.; Mandrand, B.; Levillain, E.; Roncali, J. J. Electroanal. Chem. 2009, 626, 42−46. (18) Nguyen Duc, T.; El Zein, R.; Raimundo, J.-M.; Dallaporta, H.; Charrier, A. M. J. Mater. Chem. B 2013, 1, 443−446. (19) Didane, Y.; Mehl, G. H.; Kumagai, A.; Yoshimoto, N.; VidelotAckermann, C.; Brisset, H. J. Am. Chem. Soc. 2008, 130, 17681−17683. (20) Didane, Y.; Kumagai, A.; Yoshimoto, N.; Videlot-Ackermann, C.; Brisset, H. Tetrahedron 2011, 67, 1628−1632. (21) Lucas, B.; Trigaud, T.; Videlot-Ackermann, C. Polym. Int. 2012, 61, 374−389 and references therein.. (22) Satapathy, R.; Wu, Y.-H.; Lin, H.-C. Chem. Commun. 2012, 48, 5668−5670. (23) For more information, see the Website of Spectropôle from AixMarseille University: http://www.spectropole.u-3mrs.fr/presentation0. htm. (24) (a) Yoe, J. H.; Jones, A. L. Anal. Chem. 1944, 16, 111−115. (b) Job, P. Spectrochemical Methods of Analysis; Wiley Intersience: New York, 1971, p 346. (25) Letizia, J. A.; Cronin, S.; Ponce Ortiz, R.; Fachetti, A.; Ratner, M. A.; Marks, T. J. Chem. Eur.J. 2010, 16, 1911−1928. (26) Aboubakr, H.; Tamba, M.-G.; Diallo, A. K.; Videlot-Ackermann, C.; Belec, L.; Siri, O.; Raimundo, J.-M.; Mehl, G. H.; Brisset, H. J. Mater. Chem. 2012, 22, 23159−23168. (27) (a) Stetter, H. Chem. Ber. 1953, 86, 161−167. (b) Cheeseman, G. W. H. J. Chem. Soc. 1962, 1170−1176. (c) Shirai, Y.; Osgood, A. J.; Zhao, Y.; Yao, Y.; Saudan, L.; Yang, H.; Yu-Hung, C.; Alemany, L. B.; Sasaki, T.; Morin, J.-F.; Guerrero, J.; Kelly, K. F.; Tour, J. M. J. Am. Chem. Soc. 2006, 128, 4854−4864. (28) The DMSO was not pretreated, containing estimated 0.3% v/v water. (29) The observed artifact around 350 nm is attributed to the light source switching. (30) Raad, F. S.; El-Ballouli, A. O.; Moustafa, R. M.; Al-Sayah, M. H.; Kaafarani, B. R. Tetrahedron 2010, 66, 2944−2952. (31) (a) Hofmeister, F. Arch. Exp. Pathol. Pharmakol. 1888, 24, 247− 260. (b) Lo Nostro, P.; Ninham, B. W. Chem. Rev. 2012, 112, 2286− 2322. (32) (a) Thordason, P. Chem. Soc. Rev. 2011, 40, 1305−1323. (b) Benesi, H. A.; Hildebrand, J. H. J. J. Am. Chem. Soc. 1949, 71, 2703−2707. (c) Scott, R. L. Rec. Trav. Chim. Pays-Bas 1956, 75, 787− 789. (d) Fielding, L. Tetrahedron 2000, 56, 6151−6170.

applications. Further work and improvements are now in progress.

■

ASSOCIATED CONTENT

S Supporting Information *

Figures S1−S9. This material is available free of charge via the Internet at http://pubs.acs.org.

■

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. Fax: +33 494 142 786. Phone: +33 494 146 724. *E-mail: [email protected]. Fax: + 33 491 418 916. Phone: + 33 491 829 367. Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work was supported by the Centre National de la Recherche Scientifique (CNRS) and the Ministère de l’Enseignement Supérieur et de la Recherche (MESR). We also thank Michel Giorgi (Spectropôle, Marseille) for the crystal structure determinations. H.A. thanks also the Ministère de l’Enseignement Supérieur et de la Recherche for its doctoral financial support.

■

REFERENCES

(1) Mangani, S.; Ferraroni, M. Supramolecular Chemistry of Anions; Bianchi, A., Bowman-James, K., Garcia-Espana, E., Eds.; John WileyVCH: New York, 1997; Chapter 3, p 63. (2) Puljak, L.; Kilic, G. Biochim. Biophys. Acta 2006, 1762, 404−413. (3) Weiner, M. L.; Salminen, W. F.; Larson, P. R.; Barter, R. A.; Kranetz, J. L.; Simon, G. S. Food Chem. Toxicol. 2001, 39, 759−786. (4) (a) Yang, M. D.; Sykes, R. M. Ecol. Mod. 1998, 105, 129−139. (b) Monteagudo, L.; Moreno, J. L.; Picazo, F. Water Res. 2012, 26, 2759−2771. (c) Martin, J. P.; Fournier, W. J. C. R. Phys. 2002, 3, 867− 877. (d) Matzer, W. E. Environ. Forensics 2001, 2, 301−311. (e) Park, R. M.; Bena, J. F.; Stayner, L. T.; Smith, R. J.; Gibb, H. J.; Lees, P. S. J. Risk Anal. 2004, 24, 1099−1108. (5) (a) Jahansouz, H.; Jiang, Z.; Himes, R. H.; Mertes, M. P.; Mertes, K. B. J. Am. Chem. Soc. 1989, 111, 1409−1413. (b) Hossain, M. A.; Llinares, J.; Mason, M. S.; Morehouse, P.; Powell, D.; Bowman-James, K. Angew. Chem., Int. Ed. 2002, 41, 2335−2338. (c) Bondy, C. R.; Loeb, S. J. Coord. Chem. Rev. 2003, 240, 77−99. (d) Sessler, J. L.; Pantos, G. D.; Gale, P. A.; Light, M. E. Org. Lett. 2006, 8, 1593−1596. (e) Gale, P. A.; García-Garrido, S. E.; Garric, J. Chem. Soc. Rev. 2008, 37, 151−190. (f) Hosseini, M. W. Coord. Chem. Rev. 2003, 240, 157− 166. (6) Molecular Recognition in Supramolecular Chemistry: From Molecules to Nanomaterials; Gale, P., Steed, J., Eds.; John Wiley & Sons, Ltd.: London, U.K., 2012. (7) Kanf, S. O.; Llinares, J. M.; Day, V. W.; Bowman-James, K. Chem. Soc. Rev. 2010, 39, 3980−4003. (8) Mateus, P.; Bernier, N.; Delgado, R. Coord. Chem. Rev. 2010, 254, 1726−1747 and references cited therein. (9) Kubik, S. Chem. Soc. Rev. 2009, 38, 585−605. (10) Kang, S. O.; Powell, D.; Bowman-James, K. Angew. Chem., Int. Ed. 2006, 45, 1921−1925. (11) Gale, P. A. Acc. Chem. Res. 2006, 39, 465−475. (12) Amendola, V.; Fabbrizzi, L.; Mosca, L. Chem. Soc. Rev. 2010, 39, 3889−3915. (13) (a) Kavallieratos, K.; Bertao, C. M.; Crabtree, R. H. J. Org. Chem. 1999, 64, 1675−1683. (b) Chen, C.-F.; Chen, Q.-Y. Tetrahedron Lett. 2004, 45, 3957−3960. (c) Kondo, S.-I.; Suzuki, T.; Yano, Y. Tetrahedron Lett. 2002, 43, 7059−7061. (d) Starnes, S. D.; Arungundram, S.; Saunders, S. D. Tetrahedron Lett. 2002, 43, 7785− 9973



Article

(33) Considering the small chemical shift changes (0.1−0.2 ppm), the binding constant is not accurately determined from the NMR data and is usually overestimated. (34) In our case, the oxidation potential value is higher due to the presence of the pyrazine skeleton on the dithienylbenzene moiety.

9974


Highly Specific and Reversible Fluoride Sensor Based on an Organic

Recommend Documents