4-(N,N-dimethylamine)benzonitrile (DMABN) derivatives with boronic acid and boronate groups: new fluorescent sensors for saccharides and fluoride ion

Two DMABN derivatives with boronic acid/boronate groups 1 and 2 were designed and synthesized for sensing saccharides and F-, respectively. Fluorescent spectral changes were observed for 1 after reaction with fructose, galactose, mannose and glucose, and the corresponding binding constants were estimated. The results show that compound 1 can bind fructose more strongly than other saccharides tested. Interestingly, both absorption and fluorescence spectral changes occurred for compound 2 after addition of F-, indicating that compound 2 is a potentially selective sensor for F-.