Nanomolar fluorogenic recognition of Cu(II) in aqueous medium—A highly selective “on–off” probe based on mesitylene derivative

A mesitylene based tripodal Schiffʹs base, 2,2′,2″-((1E,1′E,1″E)-(((((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(sulfanediyl))tris-(benzene-2,1-diyl))tris(azanylylidene))tris(methanylylidene))tris(4-nitrophenol), with OH as end groups has been synthesized and characterized by spectroscopic methods. The compound has been found to act as a highly sensitive (up to 3.16 nM) and selective, fluorogenic sensor toward Cu(II) ions, in aqueous medium. The fluorescence emission spectra of the sensor showed a band at 528 nm due to ESIPT phenomenon which gets quenched up to 94% in the presence of Cu(II) ions. The sensor has been shown to have no cytotoxic effect, hence can be conveniently used in biological systems as well.