双8-羟基喹啉锌的合成、表征及发光特性

Synthesis, Characterization and Photoluminescent Property of Dual 8-hydroxyquinoline Zinc

通过实验改进,得到了合成5,5′-次甲基-双8-羟基喹啉配体的最佳制备方案,使合成工艺简化,合成产率提高,将该配体和锌离子制备了一种新型的双8-羟基喹啉类金属配合物.利用红外吸收光谱、X射线衍射谱(XRD),研究了配合物的分子结构、物相结构;利用热重(TG)分析研究了配合物的热稳定性;利用紫外吸收光谱、荧光激发和发射光谱研究了该配合物的光物理性能.结果表明:DZnq2的热分解温度为346℃,具有较高的热稳定性.DZnq2的荧光发射峰位于534.5 nm,为黄绿光发射.与Znq2相比,荧光强度有所减弱,这是由于次甲基相连的两个喹啉环的扭曲导致了DZnq2的刚性和共平面性不好;由于分子共轭体系的增大,使DZnq2分子的π电子更加离域化,导致了荧光发射峰发生了红移.DZnq2有望在有机电致发光器件和有机光伏器件中的得到应用.

In this paper, a better method preparing Hqq, was obtained through improving experimental steps, which optimized the synthetic technics and increased synthetic yield. Both chemical structure and phase structure of the ligand and complexes were characterized by Infra-red absorption spectrum and X-ray diffraction（XRD）. The thermal stability of the complexes was studied by thermogravimetry（TG）. The photo-physical properties of the complexes were investigated by ultraviolet absorption spectrum（UV）, fluorescence excitation spectrum and emission spectrum. The result indicated that DZnq2 is a thermally stable material, whose decomposition temperature is 346℃. The ultraviolet absorption bands of DZnq2 are in the range of 266.7- 400 nm, with a relatively strong band tail absorption,which shows that the band-gap defect states exists in the forbidden band. The fluorescence excitation band of DZnq2 is the emission peak of 568 nm, for the orange light emission, which shows that the fluorescence emission of DZnq2 is mainly attributed to the charge transfer transitions from phenol to ring pyridine ring, while the π→π＊ transition of benzene ring is deactivated by non-radiative transition, and has no contribution to fluorescence emission.Compared with the fluorescence emission peak of Znq2, the fluorescence intensity of DZnq2 decrease, this is attributed to the distortion of two quinoline rings connected to the methylene,hence lead to the rigidity and coplanarity of DZnq2 was not good, thus affected fluorescence emission intensity;Because of the extending of the molecular conjugation system, π electron of DZnq2 is delocalized more, thus result to the red-shift of fluorescence emission peak. DZnq2 is expected to be applied in organic light emitting display and organic photovoltaic devices.