Self-assembly of Pillar[5]arene and phenazine enables FRET-based VOCs detection

With Pyridine (Py) and Tetrahydrofuran (THF) being listed as class 2B carcinogens by the World Health Organization, and considering their extensive use as volatile organic solvents (VOCs), detection of Py and THF is critically important. This study introduced a novel sensing platform CP[5]A@G based on Förster resonance energy transfer (FRET) system to successfully realized the detection of these two toxic gasses. The sensing platform CP[5]A@G was developed through supramolecular self-assembly between the coumarin-modified pillar[5]arene (CP[5]A) and phenazine derivative (G). In which, the CP[5]A acted as host molecule and energy donor, accordingly, the G acted as the guest molecule and energy acceptor. This platform CP[5]A@G exhibited significant aggregation-caused quenching (ACQ) effects in chloroform and n-hexane mixed solvent. Generally speaking, ACQ effect is untoward for luminescence properties of organic compounds and is more severe in the solid state. However, based on the ACQ property of platform CP[5]A@G, we have realized the detection of Py and THF in solvent and film states through the host-guest competitive assembly and lone pair···π interaction mechanisms. The responses were manifested in the opening and quenching effects on the fluorescence luminescence. These findings represent substantial advancements in the adsorption of Py and THF, with promising applications in commercial gas recognition systems and sensor design.