New Dopa-AIE Compound Used as Fluorescence Sensor Material: Specificity and Quantification for Cu(II)

As a paramagnetic metal ion, Cu(II) is challenging to be detected by conventional fluorescence sensor because of its unselective paramagnetic quenching effects on common fluorophores. By combining catechol with tetraphenylethene, a typical aggregation-induced emission (AIE) moiety, we have successfully synthesized a new kind of catechol, the dopa-AIE compound. Due to the properties of AIE core, the catechol has the turn on mechanism as a fluorescence chemosensor. Specifically, the new catechol has the unique detection selectivity on Cu(II) in solution. The fluorescence intensity has the maximum value when the molar ratio of the catechol to Cu(II) is 1:1. Before and after this point, the fluorescence intensity shows a linear relationship with the copper ion concentration, increasing or decreasing. Thus, the quantitative calculation for Cu(II) or the dopa-AIE compound could be done according to this response process.