Fluorometric sensor based on Thiacalix[4]arene

A new thiacalix[4]arene based fluorescent chemosensor thiacalix[4]arene-N-(quinolin-8-yl)acetamide (TCAN8QA) has been synthesized and characterized by 1H-NMR, FT-IR, ESI-MS and 13C-NMR spectroscopic techniques. TCAN8QA has been found to exhibit highly selective behavior for F- ions among all other anions e.g., Cl-, Br-, I-, PO4-3, OH-, H2PO4- and CH3COO- in the absorption spectra as well as in the emission spectra. Red shift and quenching in emission spectra constituting the signature for fluoride detection is due to photoinduced charge transfer (PCT) which can be attributed to deprotonation of acidic -NH proton in the presence of fluoride ions. Observation is also confirmed by ESI-MS, NMR and FTIR spectral analysis.