Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK.
Chemistry. 2018 Oct 26;24(60):16170-16175. doi: 10.1002/chem.201803766. Epub 2018 Oct 9.
The degree of aggregation of neutral, 9-coordinate rare earth coordination complexes has been shown to affect their ligand field, as revealed by diffusion-ordered NMR spectroscopy (DOSY-NMR) measurements on Y(III) complexes, paramagnetic NMR analyses of Yb and Tb analogues and emission spectral studies with the Eu systems. In non-polar media a lipophilic tris-isopropyl complex, [Ln.L ] tends to aggregate in chloroform and dichloromethane giving rise to oligomers, whereas in acetic and trifluoroacetic acid the more polar parent complex, [Ln.L ], also aggregates, profoundly affecting the pseudocontact shift and the form of the Eu emission spectrum. Such behaviour has important implications in the design of responsive spectral probes.
中性、9 配位稀土配合物的聚集程度已被证明会影响其配体场，这可以通过对 Y(III)配合物的扩散有序 NMR 光谱（DOSY-NMR）测量、Yb 和 Tb 类似物的顺磁 NMR 分析以及 Eu 体系的发射光谱研究来揭示。在非极性介质中，亲脂性的三异丙基配合物 [Ln.L ] 倾向于在氯仿和二氯甲烷中聚集，形成低聚物，而在乙酸和三氟乙酸中，极性更大的母体配合物 [Ln.L ] 也会聚集，这会深刻影响赝接触位移和 Eu 发射光谱的形式。这种行为在响应光谱探针的设计中具有重要意义。
