A rhodamine-nitronaphthalimide Hg(II) complex for the simultaneous detection of oxidised and reduced glutathione

© 2019 Dual-fluorophore systems have attracted attention as they offer versatile photophysical properties and multiple mechanisms for sensing. Here we report that the Hg2+ complex of rhodamine-nitronaphthalimide conjugate 1 functions as a switch-on sensor for the simultaneous detection of reduced (GSH) and oxidised (GSSG) glutathione via a resonance Rayleigh scattering process, with detection limits of 4.3 μM and 11.9 μM, respectively. Hydroxide anion regenerates nitronanphthalimide 1 causing the fluorescence to “switch-off”, and the system is recyclable. This photophysical behaviour towards Hg2+, GSH and HO‾ forms the basis of a molecular level INHIBIT and AND logic gate.