A highly selective and sensitive “Turn-On” fluorescence chemosensor for the Cu 2+ ion in aqueous ethanolic medium and its application in live cell imaging

Abstract

Abstract A new rhodamine 6G derived chemosensor L has been synthesized that selectively detects the presence of Cu 2+ ion over a host of other biologically important and environmentally relevant metal ions in aqueous alcoholic medium under physiological pH (ethanol: water, 1:1, v/v, pH 7.2). The significant enhancement of fluorescence intensity of L is caused by Cu 2+ ion induced cleavage of spirolactum bond in the rhodamine moiety. This mechanism is well supported by the crystal structure of the L-Cu 2+ complex that depicts two ligand units are bonded to two Cu 2+ ions. Color of the solution changes from light orange to dark pink upon metal binding which allows naked eye detection ion as well. Confocal microscopic experiments validate that the dye is potentially useful for the selective detection of Cu 2+ ion in living cells. Therefore the dye is an excellent fluorogenic and chromogenic chemosensor for the Cu 2+ ion in aqueous ethanolic medium and the living cell as well.