Studies On Incorporating 8-hydroxylquinoline Into Macromolecules And Light Emission Property Of Complex Of The Polymer With Rare-earth Ion

In this investigation, polyacryloyl chloride was prepared by reacting of polyacrylic acid ( PAA) with SOCl2 firstly, then it was used to react with 8-hydroxylquinoline (8HOQ), the PAA containig 8HOQ side groups was synthesized, which is designated as PAA8q, so the incorporating of 8-hydroxylquinoline into macromolecules was realized. The complex of Eu(Ⅲ)- PAA8q was obtained by coordination reaction of PAA8q with rare-earth ion Eu(Ⅲ), the rare-earth—polymer complex the structure and composition of the rare-earth—polymer complex was characterized using FTIR and UV, its content of Eu(Ⅲ) was measured by volumetric method, and its fluorescence character and emission mechanism was studied on details. The results show that the esterifying reaction occurs firstly, in turn the Friess rearrangement reaction takes place and quinoline ring is acylated when polyacryloyl chloride interreacts with 8HOQ, so that the incorporating 8HOQ into macromolecules is realized. The yield of 8HOQ incorporating into macromolecules is 36.5%, and there is one 8-hydroxylquinoline molecule in 15.6 units of PAA on an average. Owing to the stronger coordinating ability of 8-hydroxylquinoline as ligand,the coordination reaction of 8HOQ with Eu(Ⅲ)is predominant over the coordination reaction of -COOH in PAA8q. The optimum reaction conditions for the coordination reaction determined are as follows. The feed ratio of 8HOQ in PAA8q to EuCl3 is 1:1, pH is 7.5, the reaction temperature is 45℃, and the reaction time is 45 min. The complex of Eu(Ⅲ)- PAA8q has stronger ability of absorbing energy because of great conjugate system of 8-hydroxylquinoline molecule and easieness of π-π* transition. Besides, the f* energy level of ion Eu(Ⅲ) is matchable with the lowest energy level of triplet state of 8-hydroxylquinoline, and the intramolecular energy transfer occurs from 8-hydroxylquinoline to Eu(Ⅲ) easily, i.e. 8-hydroxylquinoline is called to have 'aerial effect', so that The complex of Eu(Ⅲ)- PAA8q has stronger fluorescence emission, and its intensity of fluorescence emission is 14 times stronger than EuCl3.