Hao Chao-wei, Zhao Ying, Xu Yi-zhuang, Wang Du-jin, Xu Duan-fu
State Key Laboratory of Polymer Physics and Chemistry, Joint Laboratory of Polymer Science and Materials, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2008 Sep;28(9):2115-8.
In order to investigate the relationship between the aggregation structure and fluorescence properties of composites of rare earth fluorescent complexes and polymers, the fluorescent complexes of Eu(TTA)3 x 2H2O and Eu(TTA)3 x (TPPO)2 were synthesized by the reaction of TTA (2-thenoyltrifluoroacetone), TPPO (triphenylphosphine oxide) and EuCl3, and their composites with polyvinylpyrrolidone (PVP K30) were prepared. The fluorescence spectroscopy, FTIR spectroscopy and TEM were used to characterize these composites. Fluorescence spectroscopy results indicated that the fluorescence intensity of the PVP/Eu(TTA)3 x 2H2O composites is obviously improved compared with that of the Eu(TTA)3 x 2H2O complexes. For the composites with the molar ratio of the complexes to the repeat unit of PVP being 1:35, the intensity of 612 nm emission peak of the composites is 5.5 times for PVP/Eu(TTA)3 x 2H2O and 0.3 times for PVP/Eu(TTA)3 x (TPPO)2 higher than that of the corresponding pure rare earth fluorescent complexes. And the emission intensity ratio of 612 to 590 nm peak is 14.7 in PVP/Eu (TTA)3 x 2H2O composite, larger than that of Eu(TTA)3 x 2H2O complexes. These results suggested that the luminescent properties of the europium fluorescent complexes were obviously enhanced in the presence of PVP matrix and there are interactions between the fluorescence complexes and PVP molecules. In the presence of PVPK30, the FTIR spectra of the Eu(TTA)3 x 2H2O complexes were obviously influenced as well. Based on the curve-fitting results of IR spectra of PVP/Eu(TTA)3 2H2O composites with the molar ratio of repeat unit of PVP to Eu(TTA)3 x 2H2O being 7:1 and 2:1, multiple absorption peaks of nu C=O are observed. The IR spectral variations indicated that there are coordination interactions between Eu3+ ions and the carbonyl groups of PVP, and multiple coordination fashion exists. TEM results showed that there are microphase separation structures in PVP/Eu(TTA)3 x 2H2O and PVP/Eu(TTA)3 x (TPPO)2 composites. The microphase separation phenomenon in composite of PVP/Eu(TTA)3 x (TPPO)2 is more obvious than that of the PVP/Eu(TTA)3 x 2H2O. And the Europium complexes are in amorphous state, which further proved the interactions between PVP molecules and the rare earth fluorescence complexes Eu(TTA)3 x 2H2O and Eu(TTA)3 x (TPPO)2.
为了研究稀土荧光配合物与聚合物复合材料的聚集结构和荧光性能之间的关系，通过2-噻吩甲酰三氟丙酮（TTA）、三苯基氧化膦（TPPO）与EuCl₃反应合成了Eu(TTA)₃·2H₂O和Eu(TTA)₃·(TPPO)₂荧光配合物，并制备了它们与聚乙烯吡咯烷酮（PVP K30）的复合材料。采用荧光光谱、傅里叶变换红外光谱（FTIR）和透射电子显微镜（TEM）对这些复合材料进行了表征。荧光光谱结果表明，PVP/Eu(TTA)₃·2H₂O复合材料的荧光强度比Eu(TTA)₃·2H₂O配合物明显提高。对于配合物与PVP重复单元摩尔比为1:35的复合材料，PVP/Eu(TTA)₃·2H₂O复合材料612 nm发射峰强度比相应纯稀土荧光配合物高5.5倍，PVP/Eu(TTA)₃·(TPPO)₂复合材料则高0.3倍。在PVP/Eu(TTA)₃·2H₂O复合材料中，612 nm与590 nm峰的发射强度比为14.7，大于Eu(TTA)₃·2H₂O配合物。这些结果表明，在PVP基质存在下，铕荧光配合物的发光性能明显增强，且荧光配合物与PVP分子之间存在相互作用。在PVPK30存在下，Eu(TTA)₃·2H₂O配合物的FTIR光谱也受到明显影响。基于PVP/Eu(TTA)₃·2H₂O复合材料（PVP重复单元与Eu(TTA)₃·2H₂O摩尔比为7:1和2:1）的红外光谱曲线拟合结果，观察到多个ν C=O吸收峰。红外光谱变化表明Eu³⁺离子与PVP的羰基之间存在配位相互作用，且存在多种配位方式。TEM结果表明，PVP/Eu(TTA)₃·2H₂O和PVP/Eu(TTA)₃·(TPPO)₂复合材料中存在微相分离结构。PVP/Eu(TTA)₃·(TPPO)₂复合材料中的微相分离现象比PVP/Eu(TTA)₃·2H₂O更明显。且铕配合物处于非晶态，这进一步证明了PVP分子与稀土荧光配合物Eu(TTA)₃·2H₂O和Eu(TTA)₃·(TPPO)₂之间的相互作用。
