Synthesis And Properties Of Naphthalimide-Rhodamine Amphiphilic Block Copolymers

Fluorescent probes have been developed as a new method to sensing amount of species such as H proton and metal ions and attracted considerable attentions.In contrast to traditional fluorescent probes,ratiometric fluorescent probes based on F?rster resonance energy transfer?FRET?process have attracted more and more attentions because of their many advantages,such as,high sensitivity,good selectivity and a very low detection limit.Rhodamine derivatives modified with spirolactam structures are colorless and nonfluorescent,which can be transformed into colored and highly fluorescent ring-opened amide forms in the presence of special metal ions.Rhodamine derivatives are potentially served as novel fluorescent probes for H proton and metal ions.Normally,the emission bands of naphthalimide derivatives overlap well with the absorption bands of rhodamine derivatives,thus,many naphthalimide-rhodamine ratiometric fluorescent probes based on FRET have been designed and synthesized,in which naphthalimide and rhodamine derivatives are used as donors and acceptors,respectively.The naphthalimide and rhodamine moieties introducing into poly?N-isopropyl acrylamide??PNIPAM?can obtain a new water-soluable polymeric ratiometric fluorescent probe.In this thesis,the reversible addition-fragmentation chain transfer?RAFT?radical polymerization has been applied to obtain copolymers.Two copolymer fluorescent probes,P?NIPAM-co-BMPN-co-R6GEM?and P?NIPAM-co-BMPN-co-6RGEM?-b-PVK have been successfully synthesized from a rhodamine 6G derivative?R6GEM?,a naphthalimide derivative?BMPN?,N-isopropyl acrylamide?NIPAM?and N-vinyl carbazole?NVK?.The chemical structure of these copolymers have been characterized by Fourier infrared?FT-IR?spectra,proton nuclear magnetic resonance spectroscopy?¹H NMR?and high temperature gel permeation chromatography?GPC?,and then the optical prroperties of copolymers has been explored by ultraviolet-visible?UV-Vis?absorption spectra and photo luminescence?PL?spectra.?1?Two kinds of monomers,N-?rhodamine 6G?lactamethyl-2-methyl acrylamide?R6GEM?,N-butyl-4-[4-?2-ethylmethacrylate?-1-piperazineyl]-1,8-napht-halimide?BMPN?,have been synthesized,and their chemical structures have been characterized by¹H NMR and FT-IR spectra.?2?The RAFT polymerization has been applied to obtain copolymer P?NIPAM-co-BMPN-co-R6GEM?basedonFRETprocessbyusing S-1-Dodecyl-S'-??,?'-dimethyl-?�-acrylic acid?-trithiocarbonate?DDMAT?as a RAFT reagent.The chemical structure of the copolymer has been characterized by FT-IR spectra,¹H NMR spectra and GPC,and then the optical properties of the copolymer responsive to pH,Fe³⁺ion and environment temperature have been investigated.It has been found that there are good linear relationships on the ratio of555-nm to 520-nm PL intensities(I₅₅₅/I₅₂₀)in ranges of pH?2.1³.3?,the concentration of Fe³⁺?1�10^-55 M⁷.5�10^-33 M?,and temperature?25⁴5 ^oC?.The copolymer can detect the change of pH and the existence of Fe³⁺in complex systems.The copolymer can be used as the ratiometric fluorescent probes for pH,Fe³⁺and temperature.?3?The RAFT polymerization has been applied to obtain a block copolymer,P?NIPAM-co-BMPN-co-R6GEM?-b-PVK,based on double FRET processes by using P?NIPAM-co-BMPN-co-R6GEM?as a macro-RAFT reagent.The chemical structure of the copolymer has been characterized by FT-IR,¹H NMR and GPC spectra,and then the optical properties of the block copolymer responsive to pH,Fe³⁺ion and environment temperature have been investigated.As the ratiometric fluorescent probes for pH,Fe³⁺and temperature,it has been found that PVK can effectively enhanced the detected signals in the block copolymer for excitation at 340 nm.