Nuclear Magnetic Resonance Spectroscopy Investigations of Naphthalene-Based 1,2,3-Triazole Systems for Anion Sensing

Detailed Nuclear Magnetic Resonance (NMR) spectroscopy investigations on a novel naphthalene-substituted 1,2,3-triazole-based fluorescence sensor provided evidence for the "turn-on" detection of anions. The one-step, facile synthesis of the sensors was implemented using the "Click chemistry" approach in good yield. When investigated for selectivity and sensitivity against a series of anions (F-, Cl-, Br-, I-, H2PO4-, ClO4-, OAc-, and BF4-), the sensor displayed the strongest fluorometric response for the fluoride anion. NMR and fluorescence spectroscopic studies validate a 1:1 binding stoichiometry between the sensor and the fluoride anion. Single crystal X-ray diffraction evidence revealed the structure of the sensor in the solid state.