Acid-base behavior of 3-aminoquinoline in its ground and excited states

摘要: Abstract Electronic absorption and fluorescence spectroscopic techniques reveal that the pK b for neutral form (N) of 3-aminoquinoline (3AQ) is 5–5.7, in ground as well first electronically excited state. However, case quite different second , involving monocation dication. The emissive state found to be monocationic, even highly acidic conditions nafion membrane, where molecule predominantly dicationic. This indicates dication loses a proton its state, possibly due delocalization lone pair on amino nitrogen atom over ring, an intramolecular charge transfer. values have been computed using density functional theory (DFT) equilibria neutral ⇆ monocation monocation ⇆ dication respectively reasonably good agreement with experimental observations.