Synthesis And Photoluminescence Properties Of New Schiff Base Type Polymer-rare Earth Complexes

Present electroluminescent materials, the polymer-rare earth complexes which launch the fluorescent is a kind of high performance material. This materials has both excellent luminescence properties of small molecule rare earth complexes, and at the same time also have fine mechanical properties of high polymer, has a very broad application prospects in high-tech fields such as photoluminescence and electroluminescence and solar energy conversion. By macromolecular reaction and molecular design, this study has bonded the salicylaldehyde type bidentate schiff base ligands in the side chain of macromolecule of polysulfone, with rare earth ions coordination, several kinds of new type polymer-rare earth complexes luminescence materials were to be carried out, in-depth studied on the structure and the relationship between the fluorescence properties and the luminescence principle, and the valuable research results were obtained. This paper research has great scientific significance on the development and design of bond-type polymer-rare earth complexes materials.Firstly, with 1,4-dichloro methoxy butane as chloromethylation reagent, chloromethylation polysulfone(CMPSF) was obtained; subsequently,the nucleophilic substitution reaction between CMPSF and 4-hydroxysalicylaldehyde(HSA) was carried out, and salicylaldehyde(SA) as a group was bonded on the side chain of PSF, resulting in the modified PSF, PSF-SA. The Schiff base reaction was conducted between the aldehyde group of PSF-SA and the primary amino group of aniline(AN) and cyclohexylamine(CA) respectively, and two bidentate Schiff base ligand-functionalized PSFs, PSF-SAN and PSF-SCA were obtained. The chemical structure of these functionalized polysulfone and intermediate structure were fully characterized by FTIR and 1H-NMR spectra. Focuses on the main factors of nucleophilic substitution reaction between CMPSF and HSA, and optimized the reaction conditions. Experimental results show that the nucleophilic substitution reaction between HSA and CMPSF follow the single molecule nucleophilic substitution reaction(SN1), the concentration of nucleophilic reagent HSA had no effect on the size of reaction rate, but the polarity of solvents and reaction temperature were two most important factors affecting the reaction. Appropriate reaction condition is: using the strong polar N,N-dimethyl acetamide(DMAC) as solvent, anhydrous sodium carbonate as an acid binding agent, under 80 ℃ temperature response 12 h, an amount of SA bonding tendency for 1.346 g modified polysulfone PSF-SA. While the schiff base reaction between PSF-SA and four primary amines is much easier to, for example, with DMAC as solvent, reaction under condition of 65℃ and 8 hours, the functionalized polysulfone PSF-SAN can be obtained with SAN bond content of 0.997 mmol/g, the preparation of the other three functionalization of polysulfone schiff base reaction is also easy to make.Next, making the two different structures of bidentate Schiff base functionalized polysulfone PSF-SAN and PSF-SCA, sequentially coordinated with Eu(Ⅲ) and Tb(Ⅲ) ion, luminous binary polymer-rare earth complexes PSF-(SAN)3-Eu(Ⅲ) and PSF-(SCA)3-Tb(Ⅲ) were synthesized respectively; and 1,10-phenanthroline(Phen) as the second ligand, the ternary polymer-rare earth complexes PSF-(SAN)3-Eu( Ⅲ)-(Phen)1 and PSF-(SCA)3-Tb(Ⅲ)-(Phen)1 were also obtained. The chemical structures of these complexes were characterized by ultraviolet absorption spectrum(UV) and infrared spectroscopy, and delved into their light-emitting principle and fluorescent properties. Experimental results show that binary polymer-rare earth complexes PSF-(SAN)3-Eu(Ⅲ) emits strong characteristic fluorescence(red light) of Eu(Ⅲ) ion, and PSF-(SCA)3-Tb(Ⅲ) emits intensity characteristic fluorescence(green light) of Tb(Ⅲ) ion, the triplet energy level of bonding ligand SAN and SCA, respectively, match with the Eu(Ⅲ) and Tb(Ⅲ) ion resonance level, can respectively sensitizing Eu(Ⅲ) and Tb(Ⅲ) ions of fluorescence emission, a strong intramolecular energy transfer, namely can Antenna effect to be used. In addition, two kinds of ternary complexes of the fluorescence emission intensity is much stronger than the corresponding binary complexes, fully show the small molecular ligands Phen two roles: collaborative coordination and replace the coordinated water molecules.Finally, the Schiff base reaction was conducted between the aldehyde group of PSF-SA and the primary amino group of methoxy aniline(MAN) and the hydroxy aniline(HAN) respectively, and two bidentate Schiff base ligand-functionalized PSFs, PSF-SMAN and PSF-SHAN were obtained. Then the two functional polysulfone, PSF-SMAN and PSF-SHAN, with electron donating substituent(methoxyl and hydroxyl) on the benzene rings, coordinate with the Eu(III) ions respectively, the binary complexes PSF-(SMAN)3-Eu(Ⅲ) and PSF-(SHAN)3-Eu(Ⅲ) were allowed to be carried out; again with small molecular Phen as the second ligands, the ternary complexes PSF-(SMAN)3-Eu(Ⅲ)-(Phen)1 and PSF-(SHAN)3-Eu(Ⅲ)-(Phen)1 were also to be prepared. Use various methods to the structure characterization of these complexes, and have mainly studied electron donating substituent on the benzene ring effect on the luminescence properties of complexes.Results show that compared with polymer-rare earth complexes that no substituent on benzene ring, PSF-(SAN)3-Eu(III) and PSF-(SAN)3-Eu(III)-(Phen)1, the complexes with methoxy or hydroxyl substituent are both to fluorescence emission intensity bigger, both the methoxyl and hydroxy are all with benzene occur p-π conjugation effect, reduces the inspire singlet energy of ligand(SMAN or SHAN), also with the decrease of the triplet energy, thereby enhancing the matching degree between the lowest triplet states of ligands and resonance level of Eu(III) ion, then fluorescence emission of the ligands has stronger sensitization, and make the luminous intensity of complexes also increased.