Electron-rich anthracene-based twisted π-system as a highly fluorescent dye: Easy recognition of solvents and volatile organic compounds

Abstract

Listen

Translate article

Discriminations of organic solvents and volatile organic compounds (VOCs) are in considerable demand and primarily developed using organic fluorophores, organometallic, and coordination complexes or polymeric materials. The development of small organic solid-state emitter with an ability to recognize organic solvents and VOCs brings significant advancement. A small electron-rich and structurally twisted anthracene based π-system have been identified as stable and strong solvatofluorochromic material with 109 nm redshift ranging from green fluorescence in hexane (λmax = 513 nm) to reddish-brown emission (λmax = 622 nm) in acetonitrile. Thus, it distinguishes the solvent environment of different polarity. This feature is employed to afford the paper butterfly that changes the emission with various solvent as a colourful toy upon the exposure of a 365 nm UV-lamp. This strong solid-state emitter is utilized to identify volatile organic compounds using a low-cost, handy, and small capped-bottle device. The reason behind the solvatochromism is demonstrated through the possible formation of TICT-state. The vapochromism is perhaps mainly due to solvent trapping inside the crystal lattice, where ethyl acetate could be traced with three C–H⋯O and one C–H … π interaction. Apart from the solvent effect on the electronic states, the tuning of emission colour in the solid-state is governed by the variance of noncovalent and directional intermolecular interactions.