A Dual-Functional Fluorescent Chemosensor Derived from Naphthalene Dithiouryl for Cu: Applications in Water Analysis, Logic Gates, Swab Tests, and Pesticide Monitoring.

A chemosensor (CNS) built on a naphthalene fluorophore was developed, featuring a disulfide-bridged dimer structure. The probe CNS was completely characterized by the usual spectral analysis methods like H NMR, C NMR, and HR-MS. The CNS probe selectively detects Cu ions and subsequently recognizes the amino acid tryptophan in a semi-aqueous medium of DMF:HO solution. The detection of Cu ions occur via three distinct mechanisms: suppression of the photoinduced electron-transfer process (PET), arrested rotation of diuryl groups leading to conformational change, and a blue-shifted fluorescence enhancement through intramolecular charge-transfer (ICT). With a 1:1 complexation ratio and a detection limit of 2.14 x 10 M, the CNS probe has been successfully applied in various practical scenarios, including real water sample analysis, glyphosate detection, smartphone-based color detection, and Cu ion testing using a cotton-swab method.