Evaluation of a simple and novel fluorescent anion sensor, 4-quinolone, and modification of the emission color by substitutions based on molecular orbital calculations

Article abstract of DOI:10.1016/j.tet.2006.08.060

4-Quinolone (4-QO) was evaluated as a simple and novel fluorescent anion sensor, and the modification of its emission color was carried out. The series of 4-QO derivatives having molecular orbitals with different energy levels was designed by substitutions at the 6 and 7 positions based on the molecular orbital calculations. All derivatives showed drastic fluorescence enhancements in the presence of F^- via the intramolecular charge transfer mechanism, and the successful modification of the emission color was achieved. The anion-induced emission colors of these derivatives as well as their binding affinities for F^- could be predicted by ab initio quantum chemical calculations, indicating that the present calculations are useful in designing new anion sensors.