硝基苯甲酸功能化聚砜的制备及其与Eu(Ⅲ)离子配合物发光性能之初探

Bonding of nitrobenzoic acid ligand on side chains of polysulfone and preliminarily exploring effect of nitro substituent group on photoluminescence properties of polymer-rare earth complex

以3-硝基-4-羟基苯甲酸(NHBA)为试剂,使氯甲基化聚砜(CMPSF)的氯甲基与NHBA分子中的酚羟基之间发生亲核取代反应,将硝基苯甲酸配基(NBA)键合在聚砜侧链,制得了功能化的聚砜NBA-PSF。本文重点研究了实现聚砜功能化转变的亲核取代反应,考察了主要因素的影响规律,优化了反应条件。在NBA-PSF的结构进行表征的基础上,使之与Eu(Ⅲ)离子配位,制得了高分子-稀土配合物PSF-(NBA)3-Eu(Ⅲ),初步探索了该配合物的荧光发射特性。实验结果表明,CMPSF与NHBA之间取代反应遵循S N1的反应机理;使用极性较强的溶剂(N,N-二甲基甲酰胺)及采用较高的温度(70℃),有利于反应的进行。对Eu(Ⅲ)离子的荧光发射,大分子链上的配基NBA比苯甲酸(BA)配基具有更强的敏化作用,表明芳羧酸芳环上硝基对配合物光致发光性能的正性影响。

The nucleophilic substitution reaction between the chloromethyl group of chloremethylated polysulfone（CMPSF） and phe- nolic hydroxyl group of 3 -nitro-4 -hydroxy benzoic acid （NHBA） was conducted, and the nitro-benzoic acid （ NBA ） ligand was bonded on the side chains of polysulfone（ PSF）, obtaining nitrobenzoic acid functionalized polysulfone NBA-PSF. In this work, the function- alization reaction of PSF was mainly investigated, and the effects of the main factors on the substitution reaction between CMPSF and NHBA were examined to optimize the reaction conditions. The chemical structure of NBA-PSF was characterized by FTIR and 1H- NMR spectra. The coordination reaction between NBA-PSF and Eu3＋ion was allowed to carry out, resulting in the polymer-rare earth complex,PSF-（NBA） 3-Eu（ III ）, and its florescence emission was preliminarily examined. The experimental results show that the rate of the nucleophilic substitution reaction is independent of the concentration of the nucleophile HNA, indicating that this is a typical unimolecular nucleophilic substitution reaction, i. e. SN 1. The nitro substitute group in benzene ring produces a negative effect on the substitution reaction to a certain degree. Using the solvent with stronger polarity and the increase of the reaction temporature（70℃） are favorable to the substitution reaction. The ligand NBA on the side chain of the functional polymer NBA-PSF can strongly sensitize the fluorescence-emission of Eu3＋ion, and its sensitization is much stronger than that of benzoic acid（BA） ligand, leading to that the polymer-rare earth complex PSF-（NBA） 3-Eu （ III ）possesses much stronger fluorescence emission intensity than the polymer-rare earth complex PSF-（BA）3-Eu（ III ）, displaying the positive effect of the nitro substituent group on the luminescent property of the complex. The solid film of PSF-（NBA） ：Eu（ III ）also emits strong characteristic fluorescence of Eu（ III） ion.