Tuned Al3+ selectivity and π-extended properties of di-2-picolylamine-substituted quinoline-based tolan. Issue 18 (30th April 2020)

• Record Type: Journal Article
• Authors: Ko, Min-Sung; Kurapati, Sathish; Jo, Yunhee; Cho, Beomhee; Cho, Dong-Gyu
• Is Part Of: Tetrahedron letters. Volume 61:Issue 18(2020)
• Publication Date: 2020-04-30
• Subjects: Al3+ receptor -- Quinoline -- Tolan -- Electronic effect; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2020.151808
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Di-2-picolylamine (DPA)-substituted quinoline-based tolan. Al 3+ ion selectivity over other ions. Modulated metal selectivity via electronic effects. π-Extended nature of tolan. Abstract: Di-2-picolylamine (DPA)-substituted quinoline-type tolan was synthesized herein. The electron withdrawing CN substituted tolan (1 ) exhibited clear Al 3+ selectivity, unlike simple DPA-substituted quinoline (2 ). Additionally, owing to the π-extension to quinoline (2 ), a redshifted fluorescence band and the shoulder of tolan (1 ) were observed at 491 and 537 nm, respectively, whereas the quinoline (2 ) fluorescence band was observed at approximately 450 nm. Consequently, Al 3+ bound tolan was more redshifted in comparison with other metal ions bound by 2 . Fluorescence titration of Al 3+ to 1 (20 μM) in HEPES buffer (10 mM, pH = 7.4) containing 50% MeOH exhibited a limit of detection of 36 nM.