9,9-二(丙酸二甲氨基乙酯)芴共聚物的合成及荧光性能

Synthesis and Photoluminescene of Poly((9,9-bis(dimethylaminoethylpropanoate)-2,7-fluorene)-co-2,7-(9,9-dioctylfluorene))Copolymers

采用迈克尔加成反应制备了单体2,7-二溴-9,9-二(丙酸二甲氨基乙酯)芴(FDMAEA);采用Suzuki偶合反应制备了不同FDMAEA结构单元含量的醇溶性9,9-二(丙酸二甲氨基乙酯)芴-9,9-二辛基芴共聚物(PFDMAEA)。通过核磁共振、凝胶渗透色谱、溶解性测试、紫外-可见光光谱、荧光发射光谱等对其进行了分析研究。结果表明,成功合成了2,7-二溴-9,9-二(丙酸二甲氨基乙酯)芴及9,9-二(丙酸二甲氨基乙酯)芴-9,9-二辛基芴共聚物。该共聚物在极性溶剂,如甲醇中具有良好的溶解性。由于含有DMAEA支链的PFDMAEA主链容易扭曲,共轭长度变短,共聚物的紫外吸收光谱和荧光光谱随着FDMAEA含量的增加而发生蓝移。荧光发光光谱研究表明,溶剂的极性、溶液的浓度、温度和pH值对共聚物的发光性能有很大的影响。随着溶剂极性增大,共聚物的荧光发射强度不断增加。荧光发射强度随溶液浓度的增加先增加后降低,随着溶液温度的上升而降低。当溶液pH值由1增大到14时,荧光强度不断降低,直至淬灭。

The monomer,2,7-dibromo-9,9-bis（dimethylaminoethylpropanoate）fluorene was synthesized by Michael addition reaction,and alcohol soluble poly（（9,9-bis（dimethylaminoethylpropanoate）-2,7-fluorene）-co-2,7-（9,9-dioctylfluorene））copolymers（PFDMAEA）with different contents of 9,9-bis（dimethylaminoethylpropanoate）fluorene structural unit were synthesized through Suzuki coupling.The monomer and copolymers were characterized by 1 H-NMR,gel permeation chromatography（GPC）,solubility test,ultraviolet-visible spectroscopy and photoluminescence spectroscopy.The results show that the monomer and copolymers are successfully synthesized.The copolymers have good solubility in polar solvent such as methanol.Because PFDMAEA backbone can be distorted by DMAEA side chain which decreases the conjugate length,the UV-visible absorption and the fluorescence spectra of the copolymers show a blue shift with increased content of 9,9-bis（dimethylaminoethyl-propanoate）fluorene（FDMAEA）.Photoluminescence performances of copolymers under various conditions were studied.A gradually increasing trend of fluorescence intensity of the copolymer is found with the increasing polarity of the solvents.The fluorescence intensity of the copolymer solution increases with the increasing of the copolymers concentration when the concentration is lower than 0.01 mg/mL.When the concentration is higher than 0.01 mg/mL,the quenching effect can be observed.However,with the increasing temperature of solution,the fluorescence intensity of the copolymers decreases.When the pH valur of solution varies from 1 to 14,the fluorescence emission intensity of the copolymers decreases as the pH value increases.