Development of a reversible chromogenic sensor for Cu2+ in aqueous ethanol

Abstract A naphthaldehyde appended sensor has been synthesized and characterized by spectroscopic techniques. The sensor has been efficiently utilized in selective chromogenic detection of Cu2+ in aqueous ethanol amongst various metal ions. Cu2+ interacts with the sensor in 1:2 (M:L) stoichiometry with binding constant of 1.1 ×103 M-1/2 and detection limit of 9.342 ×10-7 M. Ligand to metal charge transfer (LMCT) accounts for the selective color change from colorless to yellow with Cu2+ as suggested by UV-Vis and DFT studies. This sensor offers certain advantages over the existing chemosensors in terms of reversibility, reusability and solid state applications.