Fluorescent Recognition of 1,2-Diamines by a 1,1'-Binaphthyl-Based Trifluoromethyl Ketone

The fluorescent responses of a 1,1'-binaphthol (BINOL)-based trifluoromethyl aryl ketone toward a variety of amines have been studied. The aliphatic 1,2-diamines, especially ethylenediamine, can greatly enhance the fluorescence of this compound, but under the same conditions, other mono- and diamines cause much smaller fluorescent responses. This compound can be used as a fluorescent sensor for the detection of ethylenediamine at concentrations over micromolar levels. UV absorption and NMR spectroscopic methods have been used to study the interactions of the sensor with ethylenediamine. These studies have demonstrated that the trifluoromethyl ketone of the sensor reacts with ethylenediamine much more favorably than with other amines. The hydroxyl groups of the sensor and those of the hemiaminal adducts formed in the presence of the amines are important for the highly selective fluorescent response.