三联吡啶苯桥连β-二酮配体调控3d-4f能量传递及单分子白光研究

Regulation of 3d-4f Energy Transfer and Single Molecule White Light by Tripyridyl Benzene Bridgedβ-dione Ligand

设计并制备了三联吡啶单、双和三苯桥连β-二酮配体(SL3、DL3和TL3)及其3d-4f配合物(SL3-Zn-Eu、DL3-Zn-Eu和TL3-Zn-Eu)。研究发现,SL3-Zn-Eu和DL3-Zn-Eu在紫外激发下通过三重态能量传递敏化Eu3+的特征红光,两者色度坐标均为(0.67,0.33),主要原因是3d和4f中心距离更近,更有利于3d-4f的能量传递。然而,TL3-Zn-Eu结构中3d和4f中心距离更远,且随着桥连苯环数量的增加导致桥连苯平面扭曲,使3d→4f能量传递速率减低和单重态能量传递敏化Eu^(3+)发光。从荧光光谱中可以检测到Eu^(3+)特征红光和TL3-Zn的残余青光,其发光颜色落在白光区域,色度坐标为(0.30,0.29)。总之,本文设计的3d-4f配合物随着桥连苯数的增加,可以改变分子共轭性和3d→4f间距离,从而调节能量传递效率和传递机制,获得单分子发射白光材料。

The tripyridine mono,bis and triphenyl bridged-β-dione ligands(SL3,DL3 and TL3)and their 3d-4f complexes(SL3-Zn-EU,DL3-Zn-EU and TL3-Zn-EU)were designed and prepared.It is found that SL3-Zn-Eu and DL3-Zn-Eu can emit characteristic red light of rare earth ion Eu3+under ultraviolet excitation,and the chroma coordi⁃nates of both are(0.67,0.33),but SL3-Zn-Eu has higher luminous intensity and quantum efficiency,mainly be⁃cause the closer distance between 3d and 4f centers is favorable for 3d-4f energy transfer.However,the distance be⁃tween the 3d and 4f centers in the TL3-Zn-Eu structure is longer,and the conjugate planes of the bridled benzene in the ligand distort with the increase of the number of bridled benzene rings,resulting in the blocked energy transfer of 3d→4f.The characteristic red light of Eu3+and the residual green light of TL3-Zn can be detected from the fluores⁃cence spectrum,and the luminous color falls in the white region with chrominance coordinates of(0.30,0.29).In conclusion,the 3d-4f complex designed in this paper can change the molecular conjugacy and the distance between 3d and 4f with the increase of the number of bridging benzene,thus adjusting the energy regulation efficiency.