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

Abstract

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 µM). The formation of copper complex of 4 was confirmed by HRMS. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim