Dual mode detection of CN- & Cu2+ using fluorene moiety with logic gate, DFT studies and real sample analysis applications.

A simple colorimetric receptor was synthesized by the condensation of 2-amino fluorene with 2-hydroxy-5-nitrobenzaldehyde and its properties were investigated using colorimetric, fluorescence and DFT studies. The sensing mechanism was ascertained by 1H NMR titration studies. The synthesized receptor showed two-pronged chemosensing properties and exhibited remarkable colorimetric transitions from colorless to yellow in the presence of CN- and colorless to green in the presence of Cu2+ in 80:20 acetonitrile/water medium, which could be determined by naked eye observations. The detection limit of receptor to CN- and Cu2+ ion was found to be 7.9 × 10-7 M and 4.5 × 10-8 M respectively. Receptor was also successfully employed in the construction of molecular INHIBIT and YES logic gates. The synthesized receptor was also efficiently used for real-sample analysis in Finger Millet, also known as Ragi in Tamil. Its scientific name is Eleusine coracana.