Role of the Ancillary Ligand N,N-Dimethylaminoethanol in the Sensitization of EuIII and TbIII Luminescence in Dimeric -Diketonates
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- 作者：Svetlana V. Eliseeva ; Oxana V. Kotova ; Fré ; dé ; ric Gumy ; Sergey N. Semenov ; Vadim G. Kessler ; Leonid S. Lepnev ; Jean-Claude G. Bü ; nzli ; Natalia P. Kuzmina
- 刊名：Journal of Physical Chemistry A
- 出版年：2008
- 出版时间：April 24, 2008
- 年：2008
- 卷：112
- 期：16
- 页码：3614 - 3626
- 全文大小：283K
- 年卷期：v.112,no.16(April 24, 2008)
- ISSN：1520-5215
文摘
Two types of dimeric complexes [Ln2(hfa)6(
2-O(CH2)2NHMe2)2] and [Ln(thd)2(2,
2-O(CH2)2NMe2)]2 (Ln= YIII, EuIII, GdIII, TbIII, TmIII, LuIII; hfa- = hexafluoroacetylacetonato, thd- = dipivaloylmethanato) areobtained by reacting [Ln(hfa)3(H2O)2] and [Ln(thd)3], respectively, with N,N-dimethylaminoethanol in tolueneand are fully characterized. X-ray single crystal analysis performed for the TbIII compounds confirms theirdimeric structure. The coordination mode of N,N-dimethylaminoethanol depends on the nature of the
-diketonate. In [Tb2(hfa)6(2-O(CH2)2NHMe2)2], eight-coordinate TbIII ions adopt distorted square antiprismaticcoordination environments and are O-bridged by two zwitterionic N,N-dimethylaminoethanol ligands with aTb1···Tb2 separation of 3.684(1) Å. In [Tb(thd)2(2,2-O(CH2)2NMe2)]2, the N,N-dimethylaminoethanol actsas chelating-bridging O,N-donor anion and the TbIII ions are seven-coordinate; the Tb1···Tb1A separationamounts to 3.735(2) Å within centrosymmetric dimers. The dimeric complexes are thermally stable up to180 
C, as shown by thermogravimetric analysis, and their volatility is sufficient for quantitative sublimation under reduced pressure. The EuIII and TbIII dimers display metal-centered luminescence, particularly[Eu2(hfa)6(O(CH2)2NHMe2)2] (quantum yield 
= 58%) and [Tb(thd)2(O(CH2)2NMe2)]2 (32%). Consideration of energy migration paths within the dimers, based on the study of both pure and EuIII- or TbIII-doped(0.01-0.1 mol %) LuIII analogues, leads to the conclusion that both the -diketone and N,N-dimethylaminoethanol ligands contribute significantly to the sensitization process of the EuIII luminescence. The ancillaryligand increases considerably the luminescence of [Eu2(hfa)6(O(CH2)2NHMe2)2], compared to [Ln(hfa)3(H2O)2],through the formation of intra-ligand states while it is detrimental to TbIII luminescence in both -diketonates.Thin films of the most luminescent compound [Eu2(hfa)6(O(CH2)2NHMe2)2] obtained by vacuum sublimationdisplay photophysical properties analogous to those of the solid-state sample, thus opening perspectives forapplications in electroluminescent devices.
2-O(CH2)2NHMe2)2] and [Ln(thd)2(2,2-O(CH2)2NMe2)]2 (Ln= YIII, EuIII, GdIII, TbIII, TmIII, LuIII; hfa- = hexafluoroacetylacetonato, thd- = dipivaloylmethanato) areobtained by reacting [Ln(hfa)3(H2O)2] and [Ln(thd)3], respectively, with N,N-dimethylaminoethanol in tolueneand are fully characterized. X-ray single crystal analysis performed for the TbIII compounds confirms theirdimeric structure. The coordination mode of N,N-dimethylaminoethanol depends on the nature of the-diketonate. In [Tb2(hfa)6(2-O(CH2)2NHMe2)2], eight-coordinate TbIII ions adopt distorted square antiprismaticcoordination environments and are O-bridged by two zwitterionic N,N-dimethylaminoethanol ligands with aTb1···Tb2 separation of 3.684(1) Å. In [Tb(thd)2(2,2-O(CH2)2NMe2)]2, the N,N-dimethylaminoethanol actsas chelating-bridging O,N-donor anion and the TbIII ions are seven-coordinate; the Tb1···Tb1A separationamounts to 3.735(2) Å within centrosymmetric dimers. The dimeric complexes are thermally stable up to180 C, as shown by thermogravimetric analysis, and their volatility is sufficient for quantitative sublimation under reduced pressure. The EuIII and TbIII dimers display metal-centered luminescence, particularly[Eu2(hfa)6(O(CH2)2NHMe2)2] (quantum yield = 58%) and [Tb(thd)2(O(CH2)2NMe2)]2 (32%). Consideration of energy migration paths within the dimers, based on the study of both pure and EuIII- or TbIII-doped(0.01-0.1 mol %) LuIII analogues, leads to the conclusion that both the -diketone and N,N-dimethylaminoethanol ligands contribute significantly to the sensitization process of the EuIII luminescence. The ancillaryligand increases considerably the luminescence of [Eu2(hfa)6(O(CH2)2NHMe2)2], compared to [Ln(hfa)3(H2O)2],through the formation of intra-ligand states while it is detrimental to TbIII luminescence in both -diketonates.Thin films of the most luminescent compound [Eu2(hfa)6(O(CH2)2NHMe2)2] obtained by vacuum sublimationdisplay photophysical properties analogous to those of the solid-state sample, thus opening perspectives forapplications in electroluminescent devices.© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |