Preparation And Research On Fluorescence Emission Character Of Photoluminescence Naphthoic Acid-functionalized Polystyrene-Rare Earth Ion Complex

Bonding polymer-rare earth complexes are a kind of high performance luminescencematerials, They have not only excellent luminescence properties of rare earth complexes, butalso good mechanical properties and easy processing molding characteristics of the polymercompound. The deep research for bonding polymer-rare earth complexes luminescencematerials has important scientific significance and development prospect for the developmentof new electroluminescent materials. Through molecular design, bonding polymer-rare earthcomplexes luminescence materials were prepared by bonding naphthoic acid ligands on theside chain of linear polystyrene and the photoluminescence properties of materials werestudied, which provides a valuable reference for the development of high performancepolymer-rare earth complexes luminescence materials, The results of the research projectsfield of electroluminescent material has important scientific significance.First, the nucleophilic substitution reaction between the chloromethyl group ofchloromethylated polystyrene （CMPS） and phenolic hydroxyl group of6-hydroxy-2-naphthoic acid （HNA） was performed, and the ligand of naphthoic acid （NA）was bonded on the side chains of polystyrene （PS）, obtaining naphthoic acid-functionalizedpolystyrene PSNA. The chemical structure of PSNA was characterized by FTIR and1H-NMRspectra. In this work, the functionalization-modification reaction of PS was mainlyinvestigated. The effects of the main factors on the nucleophilic substitution reaction betweenCMPS and HNA were examined, the reaction mechanism was investigated, and the reactionconditions were optimized. The experimental results show that the rate of the nucleophilicsubstitution reaction is independent of the concentration of the nucleophile HNA, indicatingthat this is a typical unimolecular nucleophilic substitution reaction i.e. SN1. The solventpolarity is favourable for the fracture of C-Cl bond of the benzyl chloride group, and canaccelerate the substitution reaction. The increase of the reaction temperature is also advantageous to the substitution reaction.Then, the luminous secondary polymer-rare earth complex PS-（NA）₃-Eu（Ⅲ） and theternary complexe PS-（NA）₃-Eu（Ⅲ）-（Phen）₁were prepared respectively by using PSNAwhich we already prepared as a macromolecular ligand and small molecular phenanthroline（Phen） as the second ligand, coordinating with Eu（Ⅲ） ion. Similarly, other two ternarycomplexes, PS-（NA）₃-Eu（Ⅲ）-（Bipy）₁and PS-（NA）₃-Eu（Ⅲ）-（NA）₁were also prepared byusing2,2′-bipyridine （Bipy） and2-naphthoic acid （NA） as the small molecular second ligandsrespectively. The chemical structures of these complexes were characterized by FTIR and UVabsorption spectra, their florescence emission characters were examined, and especially, therelationship between their florescence emission properties and chemical structures wasinvestigated in depth, and the corresponding microcosmic mechanism was analysed byapplying Antenna effect theory. The experimental results show that all of the secondary andternary complexes formed by the coordination of PSNA and Eu（Ⅲ） ion can emit the strongcharacteristic fluorescence of Eu（Ⅲ） ion, implying that the NA ligand bonded on the sidechains of PSNA can effectively sensitized the fluorescence emission of Eu（Ⅲ） ion. The NAligand bonded on the side chains of PSNA has stronger sensibilization than benzoic acid （BA）ligand. The NA ligand bonded on the side chains of PSNA has no sensibilization for thefluorescence emission of Tb（Ⅲ） ion. The florescence emission intensity of the ternarycomplex is stronger than that of the secondary complex due to the synergism coordinationeffect of the first and second ligands. Among the three small molecular second ligands, Phen,Bipy and NA, NA has the best synergism coordination effect.Last, the Multiple-ligands binary complexes PS-（NA）_n-Eu（Ⅲ） and the ternary polymercomplexes PS-（NA）₅-Eu（Ⅲ）-（Phen）mwere prepared respectively by using PSNA which wealready prepared as a macromolecular ligand and small molecular phenanthroline （Phen） asthe second ligand, coordinating with Eu（Ⅲ） ion use of multi-ligand. The relationships amongfluorescence emission properties, the thermal stability and structure of the complexes arestudied in depth. The research results show that the apparent saturated coordination numberof the binary complexes PS-（NA）_n-Eu （Ⅲ） is10. When the structure of binary complexes is PS-（NA）₅-Eu（Ⅲ）, NA reach to saturation. On this basis, the second ligand Phen can bejoined in the binary complexes PS-（NA）₅-Eu （Ⅲ） solution to supplement the coordinationaccording to n （Phen）: n （Eu （Ⅲ））=1:1. The ternary complexes of PS-（NA）₅-Eu （Ⅲ）-（Phen）₁have not only highest fluorescence emission intensity, but also best thermal stability.