For further fundamental understanding of the nature and extent of covalency in actinyl–ligand bonding, and the benefits that this may have in the design of new ligands for nuclear waste separation, there is burgeoning interest in the nature of actinyl complexes with polydentate or multiple-point-donor ligands, such as crown ethers. There are few cases of structurally authenticated molecular actinyl–crown bonds under ambient conditions. We report here the computational characterization of AnO₂²⁺–(15-crown-5) complexes, where An = U, Np, Pu, Am, and Cm, and 15-crown-5 is the cyclic polyether ligand with five ether oxygen atoms. In the gas-phase complex, the actinyl group is located inside of the crown ether, tilted slightly out of the plane of the five equatorial oxygen atoms that coordinate the actinide metal center. The actinyl–cyclic ether complexes are found to exhibit a conventional conformation, with typical An–O_axial and An–O_equatorial distances and angles. A striking result is the enhanced stability of the insertion complex for UO₂²⁺versus NpO₂²⁺, PuO₂²⁺, AmO₂²⁺ and CmO₂²⁺, which is evaluated in the context of An–O binding strengths (esp. bonding covalency), and may have ramifications for the utility of actinyl-crown complexes in separation applications.

中文翻译：

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in基的冠醚络合物：AnO ₂（15-crown-5）²⁺（An = U，Np，Pu，Am，Cm）的计算评估

为了进一步基本了解in基-配体键的共价键的性质和程度，以及在设计用于核废料分离的新配体中可能带来的好处，人们开始对多齿或多齿的act基复合物的性质产生兴趣。点供体配体，例如冠醚。在环境条件下，很少有经过结构鉴定的分子act基-冠键的情况。我们在这里报告AnO ₂ ²⁺的计算特征–（15-crown-5）配合物，其中An = U，Np，Pu，Am和Cm，而15-crown-5是具有五个醚氧原子的环状聚醚配体。在气相络合物中，act化基位于冠醚内部，略微偏离协调coordinate系金属中心的五个赤道氧原子的平面。发现in基-环醚配合物表现出常规构象，具有典型的An–O_轴向和An–O_赤道距离和角度。一个显着结果是插入复杂的用于UO增强稳定性₂ ²⁺与NPO ₂ ²⁺，的PuO ₂ ²⁺，AMO ₂ ²⁺和CMO ₂ ²⁺，这是在An–O结合强度（尤其是键合价）的背景下进行评估的，可能对in化基冠配合物在分离应用中的效用产生影响。