Rare earth metal complexes of the proligand H₃TriNOx ([(2-^tBuNOH)C₆H₃CH₂]₃N) have been shown to afford separations of simple mixtures of rare earth metal salts. In particular, separations systems were developed for applications to technologically relevant mixtures, e.g., Nd/Dy and Eu/Y for targeted, rare earths recycling chemistry. More recently, it was demonstrated that an electron-donating derivative of the proligand H₃TriNOx^R (([(2-^tBuNOH)C₆H₃RCH₂]₃N; R = 5-OMe) influenced electronic and physical properties to effect improved separations. To further probe substituent effects, in the current work, derivatives with electron-donating and -withdrawing groups along the aryl-backbone were synthesized (R = 4-^tBu, 5-Ph, 4-CF₃). The new proligands were coordinated to rare earths (RE) through protonolysis reactions, and the resulting complexes (RE = Nd, Dy) were characterized. Dimerization equilibrium constants and molar solubility were determined where applicable. Overall, the studies indicated that increased electron-donation of the aryl-substituents resulted in an increased driving force for the dimerization of the Nd complexes. This dimerization equilibrium and resultant solubility differences were used to separate mixtures of neodymium/dysprosium as well as mixtures of europium/yttrium. These findings demonstrate the tunability of the TriNOx^3– framework to achieve tailored RE separations.

中文翻译：

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了解决定稀土（TriNOx）分离系统性能的分子因素

配体H ₃ TriNOx（[（2- ^t BuNOH）C ₆ H ₃ CH ₂ ] ₃ N）的稀土金属络合物已显示出可以分离稀土金属盐的简单混合物的功能。特别是，开发了分离系统，用于技术上相关的混合物，例如Nd / Dy和Eu / Y，用于有针对性的稀土循环化学。最近，证明了配体H ₃ TriNOx ^R（（[[（2- ^t BuNOH）C ₆ H ₃ RCH ₂ ] ₃N; R = 5-OMe）影响电子和物理性质，以改善分离效果。为了进一步探讨取代基的影响，在当前工作中，合成了沿芳基骨架带有给电子和吸电子基团的衍生物（R = 4- ^t Bu，5-Ph，4-CF ₃）。新的配体通过质子分解反应与稀土（RE）配合，并表征了生成的配合物（RE = Nd，Dy）。在适用的情况下，确定二聚平衡常数和摩尔溶解度。总体而言，研究表明芳基取代基的电子给体增加导致Nd络合物二聚化的驱动力增加。该二聚平衡和所得的溶解度差异用于分离钕/ dy的混合物以及euro /钇的混合物。这些发现证明了TriNOx ^3–框架实现定制RE分离的可调性。