Synthesis and Fluorescent Property Study of Novel 1,8-Naphthalimide-Based Chemosensors

A series of novel mono- and di-substituted N-n-butyl-1,8-naphthalimide derivatives were synthesized simultaneously via a three-step reaction. The single crystal structure of N-n-butyl-4-[N′,N′-bis(2′,4′-dichlorobenzoyl)ethylamino]-1,8-naphthalimide (3f) was determined. The UV-vis and fluorescence properties of compound 3f were investigated. The 3f showed highly selective and sensitive fluorescence changes response towards Pb(2+). A titration of monomer with Pb(2+) ion was performed. When Pb(2+) ion concentration increased from 0 to 10 eq., the fluorescent intensity of 3f decreased from 199.97 to 48.21. The pH effect on 3f showed that it is stable in a wide range of pH. The results indicated that 3f might be a probe molecule for Pb(2+).