.Highly Efficient Near-Infrared-Emitting Lanthanide(III) Complexes Formed by Heterogeneous Self-Assembly of AgI, LnIII, and Thiacalix[4]arene-p-tetrasulfonate in Aqueous Solution (LnIII = NdIII, YbIII)
.Highly Efficient Near-Infrared-Emitting Lanthanide(III) Complexes Formed by Heterogeneous Self-Assembly of AgI, LnIII, and Thiacalix[4]arene-p-tetrasulfonate in Aqueous Solution (LnIII = NdIII, YbIII)
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DOI：
10.1021/ic2019583
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发表时间：
2012-02-06
影响因子：
4.6
通讯作者：
Hoshino, Hitoshi
中科院分区：
文献类型：
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作者：
Iki, Nobuhiko;Hiro-oka, Shouichi;Hoshino, Hitoshi
硫杂杯[4]芳烃-对四磺酸盐(TCAS)、银-I和Ln(III)(=Nd-III，Yb-III)在水溶液中的非均相自组装可以方便地在近红外(NIR)区域产生以Ln(III)为中心的发光。溶液-状态研究表明，在较宽的pH范围内，Ag-I-ND-III-TCAS体系生成了一个复杂的Ag-4(I)中心点ND-III中心点TCAS(2)。相反，Ag-I-Yb-III-TCAS体系在pH约为6时得到Ag-2(I)中心点Yb-2(III)中心点TCAS(2)，在pH约9.5时得到Ag-2(I)中心点Yb-III中心点TCAS(2)。通过与已知的具有相同自组装行为的Ag-I-Tb-III-TCAS配合物的比较，提出了Yb-III配合物的结构。在Ag-2(I)中心点Yb-2(III)中心点TCAS(2)中，两个TCAS配体夹在Ag-I-Ag-I-Yb-III-Yb-III核心的循环阵列中。在Ag-2(I)中心点Yb-III中心点Tcas(2)中，Yb-III被安置在一个O-8立方体中，该O-8立方体由两个TCAS配体的八个酚性O基团通过两个S-Ag-S键连接而成。对Ag-4(I)中心点ND-III中心点Tcas(2)的结晶学分析表明，它的结构类似于Ag-2(I)中心点Yb-III中心点Tcas(2)，但它有四个键而不是两个S-银-S键。根据发光寿命估算与Ln(III)(Q)配位的水分子数如下：Ag-4(I)中心点ND-III中心点TCAS(2)，0；Ag-2(I)中心点Yb-2(III)中心点TCAS(2)，2.4；以及Ag-2(I)中心点Yb-III中心点TCAS(2)，0。这些发现与溶液状态结构是一致的。Ag-4(I)中心点ND-III中心点TCAS(2)的发光量子产率(Phi)为4.9×10~(-4)，这是在H2O中报道的第二大值。这些发现表明，O-8立方体是通过配位水的O-H振荡来绕过失活的理想环境。Ag-2(I)中心点Yb-2(III)中心点TCAS(2)和Ag-2(I)中心点Yb-III中心点TCAS(2)的PHI值分别为3.8×10~(-4)和3.3×10~(-3)，反映了Q值。总体而言，这些结果表明，三元体系有可能通过多齿配体Ln(III)和辅助金属离子的自组装来获得高效的近红外发射Ln(III)配合物，该配合物通常依赖于发色团和多齿配体的精细共价键来排出配位水。
Heterogeneous self-assembly of thiacalix[4]arene-p-tetrasulfonate (TCAS), Ag-I, and Ln(III) (= Nd-III, Yb-III) in aqueous solutions conveniently afforded ternary complexes emitting Ln(III)-centered luminescence in the near-infrared (NIR) region. A solution-state study revealed that the Ag-I-Nd-III-TCAS system gave a complex Ag-4(I)center dot Nd-III center dot TCAS(2) in a wide pH range of 6-12. In contrast, the Ag-I-Yb-III-TCAS system gave Ag-2(I)center dot Yb-2(III)center dot TCAS(2) at a pH of around 6 and Ag-2(I)center dot Yb-III center dot TCAS(2) at a pH of approximately 9.5. The structures of the Yb-III complexes were proposed based on comparison with known Ag-I-Tb-III-TCAS complexes that show the same self-assembly behavior. In Ag-2(I)center dot Yb-2(III)center dot TCAS(2), two TCAS ligands sandwiched a cyclic array of a Ag-I-Ag-I-Yb-III-Yb-III core. In Ag-2(I)center dot Yb-III center dot TCAS(2), Yb-III was accommodated in an O-8 cube consisting of eight phenolate O- groups from two TCAS ligands linked by two S-Ag-S linkages. Crystallographic analysis of Ag-4(I)center dot Nd-III center dot TCAS(2) revealed that the structure was similar to Ag-2(I)center dot Yb-III center dot TCAS(2) but that it had four instead of two S-Ag-S linkages. The number of water molecules coordinating to Ln(III) (q) estimated on the basis of the luminescent lifetimes was as follows: Ag-4(I)center dot Nd-III center dot TCAS(2), 0; Ag-2(I)center dot Yb-2(III)center dot TCAS(2), 2.4; and Ag-2(I)center dot Yb-III center dot TCAS(2), 0. These findings were compatible with the solution-state structures. The luminescent quantum yield (Phi) for Ag-4(I)center dot Nd-III center dot TCAS(2) was 4.9 X 10(-4), which is the second largest value ever reported in H2O. These findings suggest that the O-8 cube is an ideal environment to circumvent deactivation via O-H oscillation of coordinating water. The Phi values for Ag-2(I)center dot Yb-2(III)center dot TCAS(2) and Ag-2(I)center dot Yb-III center dot TCAS(2) were found to be 3.8 X 10(-4) and 3.3 X 10(-3), respectively, reflecting the q value. Overall, these results indicate that the ternary systems have the potential for a noncovalent strategy via self-assembly of the multidentate ligand, Ln(III), and an auxiliary metal ion to obtain a highly efficient NIR-emissive Ln(III) complex that usually relies on elaborate covalent linkage of a chromophore and multidentate ligands to expel coordinating water.