Tuning the Triplet Energy Levels of Pyrazolone Ligands to Match the 5D0 Level of Europium(III)
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- 作者：Mei Shi ; Fuyou Li ; Tao Yi ; Dengqing Zhang ; Huaiming Hu ; and Chunhui Huang
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：November 28, 2005
- 年：2005
- 卷：44
- 期：24
- 页码：8929 - 8936
- 全文大小：174K
- 年卷期：v.44,no.24(November 28, 2005)
- ISSN：1520-510X
文摘
Three pyrazolone-based ligands, namely 1-phenyl-3-methyl-4-(1-naphthoyl)-5-pyrazolone (HL1), 1-phenyl-3-methyl-4-(4-dimethylaminobenzoyl)-5-pyrazolone (HL2), and 1-phenyl-3-methyl-4-(4-cyanobenzoyl)-5-pyrazolone (HL3), weresynthesized by introducing electron-poor or electron-rich aryl substituents at the 4-position of the pyrazolone ring.Their corresponding europium complexes Eu(LX)3(H2O)2 and Eu(LX)3(TPPO)(H2O) (X = 1-3) were characterizedby photophysical studies. The characteristic Eu(III) emission of these complexes with at most 9.2 × 10-3 of fluorescentquantum yield was observed at room temperature. The results show that the modification of ligands tunes thetriplet energy levels of three pyrazolone-based ligands to match the 5D0 energy level of Eu3+ properly and improvesthe energy transfer efficiency from antenna to Eu3+, therefore enhancing the Eu(III) emission intensity. The highestenergy transfer efficiency and probability of lanthanide emission of Eu(L1)3(H2O)2 are 35.1% and 2.6%, respectively,which opens up broad prospects for improving luminescent properties of Eu(III) complexes by the modification ofligands. Furthermore, the electroluminescent properties of Eu(L1)3(TPPO)(H2O) were also investigated.