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.

An aldehyde that is not fluorescent responsive toward a chiral diamine has been converted to a sensitive fluorescence enhancement sensor through incorporation of an additional hydrogen bonding unit to increase the structural rigidity of the reaction product of the aldehyde with the diamine. This new chiral aldehyde is synthesized in one step from the reaction of (S)-3-formylBINOL with salicyl chloride. When treated with trans-1,2-cyclohexanediamine in ethanol, it shows greatly enhanced fluorescence at λ=410 nm with good enantioselectivity. NMR and mass spectroscopic methods are used to investigate the reaction of the chiral aldehyde with the diamine. This study has revealed a two-stage reaction mechanism including a fast imine formation and a slow ester cleavage.

A 1,1′-bi-2-naphthol (BINOL)-based chiral aldehyde in combination with Zn^II shows a highly enantioselective fluorescent response toward functional chiral amines at λ>500 nm. However, the combination of salicylaldehyde and Zn^II gives the same fluorescent enhancement for both enantiomers of a functional chiral amine at λ=447 nm. By using the fluorescent responses of the combination of the BINOL-based chiral aldehyde, salicylaldehyde and Zn^II at the two emission wavelengths, both the concentration and enantiomeric composition of functional chiral amines such as amino alcohols, diamines, and amino acids can be simultaneously determined by a single fluorescent measurement. This work provides a simple and convenient method for chiral assay.