含2,6-双(咪唑-2-基)吡啶的铕(Ⅲ)和铽(Ⅲ)配合物的合成、结构及其水溶性发光性能

Synthesis,Structures and Water-soluble Luminescence Properties ofEuropium(III)and Terbium(III)Complexes Containing2,6-Bis(imidazol-2-yl)pyridine

稀土发光材料因具有尖锐的荧光发射峰、较长的荧光寿命和色谱纯度高等优点,使其在发光传感、生物探针和防伪等方面具有广泛应用。由Eu^(3+)和Tb^(3+)与2,6-双(咪唑-2-基)吡啶(PyBim,L)合成了2种新型水溶性单核镧系离子配合物(EuL_(3))Cl_(3)和(TbL_(3))Cl_(3)。固态配合物(EuL_(3))Cl_(3)和(TbL_(3))Cl_(3)是等结构的,并且均结晶在斜方晶系Pcca空间群。(EuL_(3))Cl_(3)晶胞参数为:a=1.9111(11)nm,b=1.1406(6)nm,c=1.9470(10)nm,β=90°。(TbL_(3))Cl_(3)晶胞参数为:a=1.9123(3)nm,b=1.1381(2)nm,c=1.9412(4)nm,β=90°。中心镧系元素离子通过3个PyBim配体的氮原子形成九配位的配合物,接近三帽三棱柱(D_(3h))的局部对称性。此外,通过紫外和荧光光谱仪测定2种配合物紫外吸收强度和荧光发射强度均随配合物浓度增大而增强,且呈线性关系。配合物(EuL_(3))Cl_(3)和(TbL_(3))Cl_(3)的紫外吸收强度符合朗伯比尔定律,说明其在水中具有良好溶解性。2种配合物具有高荧光发射性,(EuL_(3))Cl_(3)的量子产率为17.57%±0.01%,(TbL_(3))Cl_(3)的量子产率为16.02%±0.01%,说明PyBim配体可以作为吸收和传输光能的有效天线,敏化配位的镧系元素离子。

Rare earth luminescent materials have the advantages of sharp fluorescence emission peaks,long fluorescence lifetime and high chromatographic purity,making them widely used in luminescence sensing,biological probes and anti-counterfeiting.Two novel water-soluble mononuclear lanthanide ionic complexes,(Eu L_(3))Cl_(3)and(Tb L_(3))Cl_(3),are synthesized from the complexation of Eu^(3+)and Tb^(3+)with 2,6-bis(imidazol-2-yl)pyridine(PyBim,L).The solid-state complexes(Eu L_(3))Cl_(3)and(Tb L_(3))Cl_(3)are iso-structural and crystallize in orthorhombic Pcca group.(Eu L_(3))Cl_(3)unit cell parameters are a=1.9111(11)nm,b=1.1406(6)nm,c=1.9470(10)nm,β=90°.(Tb L_(3))Cl_(3)unit cell parameters are a=1.9123(3)nm,b=1.1381(2)nm,c=1.9412(4)nm,β=90°.The central lanthanide ions are nine-coordinated by nitrogen atoms from three pybim ligands,approaching the local symmetry of tricapped trigonal prism(D 3h).In addition,the UV absorption intensity and fluorescence emission intensity of the two complexes were measured by UV and fluorescence spectroscopy,both of which increased with the concentration of the complexes,and showed a linear relationship.The ultraviolet absorption intensity of complexes(Eu L_(3))Cl_(3)and(Tb L_(3))Cl_(3)conforms to Lambert-beer law,indicating that they have good solubility.The two complexes have high fluorescence emission,and the quantum yields of(Eu L_(3))Cl_(3)are 17.57%±0.01%and that of the(Tb L_(3))Cl_(3)are 16.02%±0.01%,respectively,indicating that pyBim ligand can serve as an effective antenna to absorb and transfer light energy,sensitizing the coordinated lanthanide ions.