Optimizing sensitization processes in dinuclear luminescent lanthanide oligomers: selection of rigid aromatic spacers.
Optimizing sensitization processes in dinuclear luminescent lanthanide oligomers: selection of rigid aromatic spacers.
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DOI：
10.1021/ja206806t
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发表时间：
2011-10-12
影响因子：
15
通讯作者：
Piguet, Claude
中科院分区：
文献类型：
--
作者：
Lemonnier, Jean-Francois;Guenee, Laure;Beuchat, Cesar;Wesolowski, Tomasz A.;Mukherjee, Prasun;Waldeck, David H.;Gogick, Kristy A.;Petoud, Stephane;Piguet, Claude
这项工作说明了一种简单的方法来优化分子双核镧系化物配合物中的镧系发光，并确定了一种特定的多齿铕配合物作为进一步掺入聚合物材料的最佳候选物。双三叉戟模型配体L3 - L5的中心苯基环被中性基团（X = H, L3）、吸电子基团（X = F, L4）或供电子基团（X = OCH3, L5）取代，分离了线性寡聚多三叉戟配体链的2,6-双（苯并咪唑-2-基）吡啶结合单元，这些配体链是为发光三价镧系元素Ln（III）的络合而设计的。L3-L5与[Ln(hfac)3（二lyme）] （hfac−为六氟乙酰丙酮阴离子）反应生成饱和单链哑铃形配合物[Ln2(Lk)(hfac)6] (k = 3 - 5)，其中两个九坐标中性单位[N3Ln(hfac)3]的镧系离子相隔12-14 Å。[Ln(hfac)3]对L3-L5中三叉戟结合位点的热力学亲和是平均的，但在毫摩尔浓度的乙腈中仍然导致15-30%的解离。除了在有机溶剂（L4 > L3比L5）中发现的经验溶解度趋势（表明L4中的1,4-二氟苯基间隔物更好）外，我们还开发了一种新的工具来解释在[Eu2(Lk)(hfac)6]中操作的光物理敏化过程。对表征能量迁移机制的完整速率常数集的简单解释为选择[Eu2(L4)(hfac)6]作为最有希望的构建块提供了直接的客观标准。
This work illustrates a simple approach for optimizing the lanthanide luminescence in molecular dinuclear lanthanide complexes and identifies a particular multidentate europium complex as the best candidate for further incorporation into polymeric materials. The central phenyl ring in the bis-tridentate model ligands L3–L5, which are substituted with neutral (X = H, L3), electronwithdrawing (X = F, L4), or electron-donating (X = OCH3, L5) groups, separate the 2,6-bis(benzimidazol-2-yl)pyridine binding units of linear oligomeric multi-tridentate ligand strands that are designed for the complexation of luminescent trivalent lanthanides, Ln(III). Reactions of L3–L5 with [Ln(hfac)3(diglyme)] (hfac− is the hexafluoroacetylacetonate anion) produce saturated single-stranded dumbbell-shaped complexes [Ln2(Lk)(hfac)6] (k = 3–5), in which the lanthanide ions of the two nine-coordinate neutral [N3Ln(hfac)3] units are separated by 12–14 Å. The thermodynamic affinities of [Ln(hfac)3] for the tridentate binding sites in L3–L5 are average , but still result in 15–30% dissociation at millimolar concentrations in acetonitrile. In addition to the empirical solubility trend found in organic solvents (L4 > L3 ≫ L5), which suggests that the 1,4-difluorophenyl spacer in L4 is preferable, we have developed a novel tool for deciphering the photophysical sensitization processes operating in [Eu2(Lk)(hfac)6]. A simple interpretation of the complete set of rate constants characterizing the energy migration mechanisms provides straightforward objective criteria for the selection of [Eu2(L4)(hfac)6] as the most promising building block.
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影响因子：
6.1
作者：
Altomare, A;Burla, MC;Spagna, R
通讯作者：
Spagna, R
DOI：
10.1107/s0108768192002453
发表时间：
1992-10-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE
影响因子：
--
作者：
BROWN, ID
通讯作者：
BROWN, ID
影响因子：
20.6
作者：
Buenzli, Jean-Claude G.;Chauvin, Anne-Sophie;Eliseeva, Svetlana V.
通讯作者：
Eliseeva, Svetlana V.
影响因子：
4.4
作者：
CARNALL, WT;FIELDS, PR;RAJNAK, K
通讯作者：
RAJNAK, K
DOI：
10.1107/s0108768190011041
发表时间：
1991-04-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE
影响因子：
--
作者：
BRESE, NE;OKEEFFE, M
通讯作者：
OKEEFFE, M