Abstract
In this contribution, a new sensitive colorimetric chemosensors based naphthalimide was synthesized and characterized by NMR and mass spectroscopic techniques. Upon the addition of OH-, the solution of dye change its color from yellowish to deep blue, which can be easily observed by naked eye. The sensors show good selective against other common anions, including strong Lewis base F−. The effects of deprotonation/protonation imposed on absorption spectrum were investigated. Further quantum chemical calculation uncovered the underlying signal mechanism. The lowered energy gap between HOMO/LUMO in NB-H leads to the longest maximum absorption (665 nm).