Naphthalimide Fluorescent Probes For Metal Ions: Molecular Design, Synthesis And Properties Investigation

This dissertation consists of two parts: Study on the naphthlimide fluorescent probes for metal ions and investigation on the photolysis mechanism of succinimides.The UV-visible and fluorescent properties of rigid 1,8-naphthalimide derivatives in various solution or under various pH were investigated. It was found that these rigid molecules are precursors of fluorescent probes sensitive to solvent polarity. N-[4-di(2-hydroxyethyl)aminophenyl]-4-(1-piperidyl)-1,8-naphthalimide was designed based on the above studies. The titration experiments indicated that it is highly selective to Fe3+.A series of novel fluorescent probes with different receptors were designed and synthesized based on the 4-amino-1,8-naphthalimide. O, N and S atoms were introduced into the receptors respectively as ligands of metal ions. At the same time, the receptors with one arm and double were introduced and it was found that the latter shows a larger blue-shift of the maximum emission than the former.Two novel fluorescent probes (D4 and D5) with a receptor containing a pair of ethanthiolyl or N,N-diethyl-dithiocarbamyl groups were designed and synthesized for recognition of transition and heavy metal ions. It was found that D4 and D5 show a pronounced fluorescence enhancement response to Cu2+ and Fe3+, respectively. They both show a strong fluorescence quenching upon addition of Hg2+. Different mechanisms of recognition for transition and heavy metal ions were proposed. The response to Cu2+ or Fe3+ is a typical PET-suppressed process. The fluorescence quenching of Hg2+ may be related to the cation-Ï€interaction, which was firstly reported in this paper.Four novel fluorescent probes with double naphthalimide fluorophores were designed and synthesized and found that they are characteristic ICT systems.The photochemical behavior of succimide in alcohol was investigated and the photolysis mechanism was proposed with the aid of DFT (density functional theory) calculations.