Visible-Light Excitable Europium(III) Complexes with 2,7-Positional Substituted Carbazole Group-Containing Ligands
Visible-Light Excitable Europium(III) Complexes with 2,7-Positional Substituted Carbazole Group-Containing Ligands
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具有 2,7 位取代咔唑基配体的可见光激发铕 (III) 配合物
DOI：
10.1021/ic901210c
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发表时间：
2009-12-07
影响因子：
4.6
通讯作者：
Gong, M. L.
中科院分区：
文献类型：
--
作者：
He, P.;Wang, H. H.;Gong, M. L.
两种新型的咔唑基β-二酮，在咔唑环上具有2-或2，7-取代基，2-（4 '4' 4 '-三氟-1 '3'-二氧代丁基）-咔唑（2-TFDBC）和2，7-双（4 '4' 4 '-三氟-1''3'-二氧代丁基）-咔唑（2，7-BTFDBC）及其铕（Ⅲ）三元配合物Eu（2-TFDBC）（3）phen和Eu-2（2，7-BTFDBC）（3）（phen）（2），其中phen为1，10-菲咯啉。通过元素分析、红外光谱、紫外-可见吸收光谱、热重分析和光致发光光谱对配合物进行了表征。热重分析表明，配合物的分解温度分别为361.4和367.3 ℃。PL测试结果表明，配合物分子中适当扩展的π共轭使激发带红移到可见光区，两种Eu（III）配合物在蓝光激发下均表现出较强的红光发射。配合物中2-TFDBC和2，7-BTFDBC的三重态能级均高于Eu 3+离子的最低激发态D-5（0），因此，Eu（III）配合物的发光机理可能是配体敏化发光过程。结果表明，Eu（2-TFDBC）（3）phen和Eu-2（2，7-BTFDBC）（3）（phen）（2）是一种很有前途的可见光激发红色荧光粉。
Two novel carbazole-based beta-diketones with 2- or 2,7-substituted groups in the carbazole ring, 2-(4'4'4'-trifluoro-1'3'-dioxobutyl)-carbazole (2-TFDBC) and 2,7-bis(4'4'4'-trifluoro-1''3'-dioxobutyl)-carbazole (2,7-BTFDBC), and their europium(III) ternary complexes Eu(2-TFDBC)(3)phen and Eu-2(2,7-BTFDBC)(3)(phen)(2) were synthesized via a dexterously designed routine, where phen is 1,10-phenanthroline. The Eu(III) complexes were characterized by elementary analysis, IR and UV-visible absorption spectroscopy, thermogravimetric analysis (TGA), and photoluminescence (PL) measurements. TGA shows that the decomposition temperatures of the complexes are 361.4 and 367.3 degrees C, respectively. PL measurement results indicated that suitably expanded pi-conjugation in the complex molecules makes the excitation band redshift to the visible region, and both the Eu(III) complexes exhibit intense red emission under blue-light excitation. The triplet state energy levels of 2-TFDBC and 2,7-BTFDBC in the complexes are higher than that of the lowest excited level of Eu3+ ion, D-5(0), so the photoluminescence mechanism of the Eu(III) complexes was proposed as a ligand-sensitized luminescence process. All of the results indicate that Eu(2-TFDBC)(3)phen and Eu-2(2,7-BTFDBC)(3)(phen)(2) are promising candidates as visible-light excitable red phosphor for luminescence applications.