2-(2,2-Bis-benzylamino-1-cyano-vinyl)-benzonitrile: A Selective Turn-off Fluorescent Cu2+ Sensor

We report design and synthesis of three 2-(2,2-bis-(alkylamino)-1-cyano-vinyl) benzonitriles and studied their metal ion sensing property. The Cu2+ ion selectively quenches the fluorescence of 2-(2,2-bis-benzylamino-1-cyano-vinyl)-benzonitrile 4 in acetonitrile. The effect of Cu2+ ion on the electronic structure of 4 was studied by TD-DFT calculations. The theoretical calculations showed good agreement with the experimental results. The detection limit of Cu2+ ion from copper nitrate for the 2-(2,2-bis-benzylamino-1-cyano-vinyl)-benzonitrile was upto 0.05 ppm (0.8 mu M). The formation of copper complex of 4 was confirmed by HRMS.