The sensitivity and selectivity properties of a fluorescence sensor based on quinoline-Bodipy Ahmed Nuri Kursunlu n , Ersin Guler Department of Chemistry, Faculty of Science, University of Selcuk, Campus, 42075, Konya, Turkey article info Article history: Received 3 June 2013 Received in revised form 13 August 2013 Accepted 14 August 2013 Available online 26 August 2013 Keywords: Bodipy Quinoline Fluorescence Sensor Complex Excitation abstract A novel florescence sensor (Q-BODIPY) based on quinoline-Bodipy (quinoline-boradiazaindacene) was prepared by ‘click chemistry’ in several stages. The sensing actions of Q-BODIPY were confirmed by UV– vis titration, emission and excitation spectroscopic studies in presence of Mn 2 þ , Co 2 þ , Ni 2 þ , Cu 2 þ , Zn 2 þ , Cd 2 þ , Sn 2 þ , Hg 2 þ , Pb 2 þ , La 3 þ , Ga 3 þ , Er 3 þ and Yb 3 þ ions in methanol:H 2 O (1:1) medium. Whereas some metal ions can only cause quenching effect on the fluorescence intensity of Q-BODIPY, some of them show an increase in fluorescence intensity. The stoichiometry of host–guest complexes formed was determined by Job′s plot method. The binding constants were calculated by Stern–Volmer method. As a fluorescence sensor, Q-BODIPY shows the best selectivity performance against Zn 2 þ ions in according to all spectroscopic data. Published by Elsevier B.V. 1. Introduction A lot of literatures report to the design, synthesis and sensing action of novel fluorescence sensor bearing structural moieties like Schiff bases [1, 2], Bodipy [3–7], Phthalocyanines [8], Porphyrins [9], etc. Among the fluorescence sensors, Bodipy sensors have been developed owing to their unique photophysical properties such as sharp emission–absorption peaks [10]. The Bodipy-derived ligands generally have a strong fluorescence and upon binding with metal ions exhibit weaker/stronger fluorescence and good photo-stability [11, 12]. The Bodipy sensors show a shift in absorption and an increasing-quenching in emission intensity upon binding with cations. Although sensing of d group metal ions by fluorometric method (based on Bodipy) has developed owing to the great concern with medicine and environment, the fluorometric sensing of p and f block metal ions have rarely studied [13–15]. A few studies show dual or trio responsive property by sensing both d and p and f group metal ions [16]. Quinoline derivatives (metal-sensing) as an excellent electron donor have been widely exploited for design and preparation of metal sensors. For example, Tian′s group reported a selective fluorescent probe of Hg 2þ based on triazole linked 8-oxyquinoline calix [4] arene by click chemistry [17]. The metal sensing of quinolone-propargyl derivatives is particularly attractive for lanthanides due to their multiple coordination [18]. In recent years, azido-cycling form click reaction has been frequently used to construct ligands with cation chelating ability [19]. Such synthetic strategies to produce quinoline-propargyl and azido-Bodipy ligands with metal ion coordinating ability offer a new approach for the design of novel fluorescence sensors [20]. In this paper, we have presented to Bodipy-quinoline (Q-BODIPY) synthesized using click chemistry as two of the key intermediate reactions. In the first step, azido-Bodipy (3) was pre- pared by treating 3-ethyl-2,4-dimethylpyrrole and a functionalized aldehyde with using trifluoroacetic acid (TFA). 8-(Prop-2-ynyloxy) quinoline (4) was prepared via propargylation of 8-hydroxyquino- line. Azido-Bodipy, 3, and alkyne-quinoline, 4, were combined by copper sulfate-catalysed cycloaddition (click chemistry) to obtain a functional metal cation fluorescent sensor. 2. Experimental section 2.1. Materials and instruments All reagents used for synthesis were obtained commercially and used without further purification. In the absorption and emission experiments, all the metal ions were added in the form of nitrate salts, which were purchased from Sigma-Aldrich and Acros, stored in a vacuum desiccator containing self-indicating silica and dried fully before using. Dichloromethane (DCM) was dried using CaH 2 and then distilled in reduced pressure. UV–vis spectra were recorded in 1 cm path length quartz cell using Perkin Elmer Lambda 25 UV–vis spectrophotometer. Emission spectra and excitation spectra were Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jlumin Journal of Luminescence 0022-2313/$ - see front matter Published by Elsevier B.V. http://dx.doi.org/10.1016/j.jlumin.2013.08.030 n Corrosponding author. Tel.: þ90 332 223 3876. E-mail addresses: ankursunlu@gmail.com, ankursunlu@hotmail.com (A. Nuri Kursunlu). Journal of Luminescence 145 (2014) 608–614