A turn-on fluorescent chemosensor for selective responses of copper(II) ion pairs

A fluorescent chemosensor was designed and synthesized by incorporating the imidazolium and 1,8-naphthalimide dye moieties into a preorganized tripodal receptor. The novel sensor displays high selectivity for Cu(ClO4)2 and Cu(NO3)2 over a wide range of tested metal ions, anions, and Cu2+ salt ion pairs. Upon adding Cu(ClO4)2 or Cu(NO3)2 to the probe solution, the fluorescence emission was significantly turned on concomitant with a blue shift in the emission energy, due to an anion-induced conformational change and coordination effect. Further binding model studies by 1H nuclear magnetic resonance spectroscopy and mass spectroscopy demonstrated that the receptor formed a 1 : 1 host–guest complex with Cu(ClO4)2 or Cu(NO3)2.

Website: http://www.arjonline.org/physical-sciences/american-research-journal-of-chemistry/