Click synthesis of a triphenylamine-based fluorescent methanol probe with a unique D-π-A structure

Facile probing organic solvents is attracting intense attention due to the growing environmental issues. Herein, for the first time, we report a novel D-pi-A structured methanol responsive fluorescence molecule (TTO), synthesized by coupling triphenylamine (electron-donor) and p-toluenesulfonyl (electron-acceptor) via Cu (I) catalytic 1,3-dipolar cycloaddition (click chemistry) forming a triazole bridge. Density functional theory (DFT) calculations and X-ray single crystal structure reveal that TTO has a highly twisted conformation and unique D-pi-A structure which render it exceptional optical properties. TTO exhibits strong fluorescence in methanol (QE>0.67) but weak fluorescence in other organic solvents (QE<0.1) including various alcohols and can be used as a highly selective fluorescence probe for methanol identification. Notably, TTO is able to excellently probe methanol from its homologue ethanol in water with a detection limit of below 0.7% (volume concentration), which demonstrates the promise potential of TTO for practical applications. (C) 2017 Elsevier B.V. All rights reserved.