Triptycene scaffolds: Synthesis and properties of triptycene-derived Schiff base compounds for the selective and sensitive detection of CN- and Cu2+

A series of triptycene-derived Schiff bases were synthesized by condensation between amino triptycenes with an appropriate aldehyde and were isolated in good to excellent (85-90%) yields. Amongst these, a triptycene-hydroxybenzaldehyde Schiff base compound proved to be a selective sensor for cyanide. It exhibited a "turn-on" fluorescence response at 490 nm to CN- facilitated by the nucleophilic addition of CN- to the aldehyde group, accompanied by a visible color change from orange to yellow. Likewise, a triptycene salicylaldehyde adduct was shown to be highly sensitive towards the detection of the CN- ion with a detection limit of 0.9 mu M. On the other hand a triptycene-BODIPY Schiff base compound could be used for the detection of Cu2+ ions over other competing, biologically relevant metal ions in acetonitrile. Photophysical studies revealed a 1:1 binding model for the triptycene-BODIPY compound. (C) 2017 Elsevier Ltd. All rights reserved.