A pair of uranyl complexes incorporating tetrahydrosalen and N,N‐dimethyltetrahydrosalen ligands are synthesized and studied. These new ligands, with saturated secondary and tertiary amines, exhibit higher chemostability than the prototype Schiff base (salen) structure, especially under acidic conditions. As shown by X‐ray diffraction crystallography, the coordination geometry of uranium in these new complexes is a distorted pentagonal bipyramid. Interestingly, UO₂([H₄]‐salen), comprising the tetrahydrosalen ligand, forms a dimeric structure in the crystals, with two subunits held together by sharing one of the two phenoxy oxygen atoms from each subunit, whereas UO₂([H₂Me₂]‐salen) with the N,N‐dimethyltetrahydrosalen ligand is in the monomer state, with a solvent molecule coordinated to uranium to complete the penta‐coordination configuration. Moreover, as revealed by UV/Vis spectroscopy using the colorimetry method, these hydrogenated salen ligands exhibit comparable, or even higher, binding affinities toward uranyl than the prototype Schiff base salen ligand in weakly basic solution.

中文翻译：

---

Tetrahydrosalen Uranyl（VI）配合物：晶体结构和溶液结合研究

合成并研究了一对掺入了四氢salen和N，N-二甲基四氢salen配体的铀酰配合物。这些具有饱和仲和叔胺的新配体比原型席夫碱（salen）结构具有更高的化学稳定性，尤其是在酸性条件下。如X射线衍射晶体学所示，这些新络合物中铀的配位几何形状是扭曲的五边形双锥体。有趣的是，包含四氢salen配体的UO ₂（[H ₄ ] -salen）在晶体中形成二聚体结构，两个亚基通过共享每个亚基的两个苯氧基氧原子之一而保持在一起，而UO ₂（[H ₂我₂ ] -salen）具有N，N-二甲基四氢salen配体处于单体状态，溶剂分子与铀配位以完成五配位构型。而且，如通过使用比色法的UV / Vis光谱法所揭示的，这些氢化的salen配体在弱碱性溶液中与原型席夫碱salen配体相比表现出可比甚至更高的对铀酰的结合亲和力。