The electrochemical properties of an anthraquinone-containing Cu2+-promoted desulfurization chemodosimeter (AQCD) in the presence of various metal ions were investigated by voltammetry. AQCD showed voltammetric changes toward divalent metal ions (M2+), which are similar to those of anthraquinone (AQ) and 1-aminoanthraquinone (AQNH2) with the metal ions except Cu2+. This can be explained on the electrostatic interaction (AQCD-M2+) and chemodosimetric reaction (AQCD-Cu2+). 1. Introduction Chemodosimeters are used for sensing an analyte through a usually rapid response, highly selective, and irreversible chemical reaction between dosimeter molecule and the target material, leading to an observable signal [1–5]. Most have been utilized as optical sensors to monitor the target by UV/Vis and fluorescence spectroscopic measurements [1, 2]. These methods are usually sensitive, easy to perform, and inexpensive, but they have limitations in portability and mobility in terms of practical sensor devices. Alternatively, analytical techniques based on electrochemical detection are suitable for the development of convenient, sensitive, selective, and low cost tools that could be exploited for rapid monitoring, ultimately applicable to hand-held or autonomous operation. However, only a few examples of electrochemical sensors using chemodosimeters have been reported [6–11]. These studies utilized ferrocene [6, 7], iridium(III) complex [8, 9], and pyridine-4-thione [10] as redox units. Previously, we reported an anthraquinone-containing chemodosimeter (AQCD) responsible for Cu2+ ion-induced desulfurization to exhibit highly selective UV and fluorescence changes (Scheme 1) [12]. Scheme 1: Anthraquinone-based chemodosimeter (AQCD) and its reaction mechanism upon Cu 2+ ion addition. The anthraquinone unit can serve not only as a chromofluorescent unit but also as a redox center. It has largely proved to be an effective, remarkable and promising redox-signaling unit for electrochemical applications due to its robust electrochemistry [13–15]. Here, we report now the redox properties as well as cation sensing behavior of AQCD in the absence and the presence of alkali, alkaline earth, Cu2+, and other metal ions by voltammetry. The present study aims to investigate the electrochemical influence of various metal ions on AQCD behavior in terms of chemodosimetric reaction confirmed previously by optical methods [12] and consequently to check the feasibility of anthraquinone-based chemodosimeter as an electrochemical sensor for metal ions. In the pursuit of this goal,
References
[1]
J. J. Du, M. M. Hu, J. L. Fan, and X. J. Peng, “Fluorescent chemodosimeters using “mild” chemical events for the detection of small anions and cations in biological and environmental media,” Chemical Society Reviews, vol. 41, no. 12, pp. 4511–4535, 2012.
[2]
D. T. Quang and J. S. Kim, “Fluoro- and chromogenic chemodosimeters for heavy metal ion detection in solution and biospecimens,” Chemical Reviews, vol. 110, no. 10, pp. 6280–6301, 2010.
[3]
K. Kaur, R. Saini, A. Kumar et al., “Chemodosimeters: an approach for detection and estimation of biologically and medically relevant metal ions, anions and thiols,” Coordination Chemistry Reviews, vol. 256, no. 17-18, pp. 1992–2028, 2012.
[4]
R. Martínez-Má？ez and F. Sancenón, “Chemodosimeters and 3D inorganic functionalised hosts for the fluoro-chromogenic sensing of anions,” Coordination Chemistry Reviews, vol. 250, no. 23-24, pp. 3081–3093, 2006.
[5]
Y. Yang, Q. Zhao, W. Feng, and F. Li, “Luminescent chemodosimeters for bioimaging,” Chemical Reviews, vol. 113, no. 1, pp. 192–270, 2013.
[6]
M. Alfonso, A. Tárraga, and P. Molina, “Ferrocenylbenzobisimidazoles for recognition of anions and cations,” Inorganic Chemistry, vol. 52, no. 13, pp. 7487–7496, 2013.
[7]
Q.-Y. Cao, M. H. Lee, J. F. Zhang, W. X. Ren, and J. S. Kim, “Ferrocene-based novel electrochemical chemodosimeter for mercury ion recognition,” Tetrahedron Letters, vol. 52, no. 21, pp. 2786–2789, 2011.
[8]
Y. Liu, M. Li, Q. Zhao, H. Wu, K. Huang, and F. Li, “Phosphorescent iridium(III) complex with an ligand as a Hg2+-selective chemodosimeter and logic gate,” Inorganic Chemistry, vol. 50, no. 13, pp. 5969–5977, 2011.
[9]
B. Lou, Z.-Q. Chen, Z.-Q. Bian, and C.-H. Huang, “Multisignaling detection of cyanide anions based on an iridium(III) complex: remarkable enhancement of sensitivity by coordination effect,” New Journal of Chemistry, vol. 34, no. 1, pp. 132–136, 2010.
[10]
T. K. Khan and M. Ravikanth, “3-(Pyridine-4-thione)BODIPY as a chemodosimeter for detection of Hg(II) ions,” Dyes and Pigments, vol. 95, no. 1, pp. 89–95, 2012.
[11]
Y.-R. Kim, H. J. Kim, M. H. Lee et al., “Electrochemically programmed chemodosimeter on ultrathin platinum films,” Chemical Communications, vol. 46, no. 44, pp. 8448–8450, 2010.
[12]
H. J. Kim, S. J. Lee, S. Y. Park, J. H. Jung, and J. S. Kim, “Detection of C by a chemodosimeter-functionalized monolayer on mesoporous silica,” Advanced Materials, vol. 20, no. 17, pp. 3229–3234, 2008.
[13]
G. Dryhurst, Biological Electrochemistry, vol. 1, Academic Press, New York, NY, USA, 1982.
[14]
M. Quan, D. Sanchez, M. F. Wasylkiw, and D. K. Smith, “Voltammetry of quinones in unbuffered aqueous solution: reassessing the roles of proton transfer and hydrogen bonding in the aqueous electrochemistry of quinones,” Journal of the American Chemical Society, vol. 129, no. 42, pp. 12847–12856, 2007.
[15]
R. H. Thomson, Naturally Occurring Quinones IV: Recent Advances, Balckie Academic & Professional, New York, NY, USA, 4th edition, 1997.
[16]
N. Gupta and H. Linschitz, “Hydrogen-bonding and protonation effects in electrochemistry of quinones in aprotic solvents,” Journal of the American Chemical Society, vol. 119, no. 27, pp. 6384–6391, 1997.
