Preparation of aromatic carboxylic acid-functionalized polysulfone and preliminary exploration of florescence emission character of formed polymer-rare earth complexes

Polysulfone (PSF) was modified via a polymer reaction, Friedel–Crafts alkylation of PSF with 4-(chloromethyl) benzoic acid (CMBA) as reaction reagent, and benzoic acid (BA) ligand was bonded onto the side chains of PSF, resulting in the aromatic carboxylic acid-functionalized PSF, BAPSF. The chemical structure of BAPSF was characterized by FTIR, 1H NMR and UV/vis absorption spectrum. BAPSF was allowed to coordinate to Eu(III) and Tb(III) ions, respectively, and two luminescent polymer-rare earth complexes, BAPSF-Eu(III) and BAPSF-Tb(III) were prepared. The fluorescence emission character of the two complexes was preliminarily explored. The functionalization modification process of PSF and the reaction mechanism were emphatically investigated. The experimental results show that the Friedel–Crafts alkylation reaction between PSF and CMBA can be carried out smoothly. The two polymer-rare earth complexes, BAPSF-Eu(III) and BAPSF-Tb(III), exhibit the characteristic fluorescence emissions of Eu3+ and Tb3+ ions, respectively. More importantly, BAPSF can powerfully sensitize the fluorescence emissions of Eu3+ and Tb3+ ions, and the effective energy transfer indeed take places from the macromolecular ligand BAPSF to the coordinated Re3+ and Tb3+ ions.