Thiazoline-pyrene selective and sensitive fluorescence "turn-on" sensor for detection of Cu²

A thiazoline and pyrene containing sensor 1 was synthesized via one-pot reaction and utilized as a highly selective and sensitive fluorescence "turn-on" sensor for Cu²⁺ detection, via the fluorescence enhancement of pyrene monomer emission. The 2:1 stoichiometry of 1 and Cu²⁺ was calculated from Job's plots based on fluorescent titrations, and the complexation of 1 with Cu²⁺ was also supported by mass spectra, Fourier transform infrared spectra, proton NMR spectra and density functional theory analysis. The fluorescence intensity of 1 at 389 nm and 410 nm increased significantly upon the addition of Cu²⁺. Limit of detection and association constant value of 1-Cu²⁺ were calculated using standard deviations and linear fittings, respectively. Results showed that 1 was active for Cu²⁺ detection in the wide pH range of 2.0-11.0.