Towards the development of controllable and reversible ‘on-off’ luminescence switching in soft-matter; synthesis and spectroscopic investigation of 1,8-naphthalimide-based PET (photoinduced electron transfer) chemosensors for pH in water-permeable hydrogels

Abstract

The synthesis of the pH PET sensors 1 and 2 is described. These mols. display on-off switching in their fluorescence as a function of pH in aq. soln. From the luminescent changes pKa values of 8.4(±0.1) and 6.3(±0.1) were detd. resp. These compds. were incorporated into poly[methylmethacrylate-co-2-(hydroxyethylmethacrylate)]-based hydrogels and the luminescent properties of the resulting polymeric films were investigated using confocal laser-scanning microscopy. Both sensors showed substantial luminescent switching in the soft-matter, where the emission was switched off after treating the hydrogels with alk. soln. and switched on under acidic conditions. [on SciFinder(R)]