Density Functional Theory Studies of Actinide(III) Motexafins (An-Motex2+, An = Ac, Cm, Lr). Structure, Stability, and Comparison with Lanthanide(III) Motexafins

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• 作者：Xiaoyan Cao ; Quansong Li ; Anna Moritz ; Zhizhong Xie ; Michael Dolg ; Xuebo Chen ; and Weihai Fang
• 刊名：Inorganic Chemistry
• 出版年：2006
• 出版时间：April 17, 2006
• 年：2006
• 卷：45
• 期：8
• 页码：3444 - 3451
• 全文大小：91K
• 年卷期：v.45,no.8(April 17, 2006)
• ISSN：1520-510X

文摘

Newly developed relativistic energy-consistent 5f-in-core actinide pseudopotentials and corresponding (7s6p5d1f)/[5s4p3d1f] basis sets in the segmented contraction scheme, combined with density functional theory methods,have been used to study the molecular structure and chemical properties of selected actinide(III) motexafins (An-Motex²⁺, An = Ac, Cm, Lr). Structure and stability are discussed, and a comparison to the lanthanide(III) motexafins(Ln-Motex²⁺, Ln = La, Gd, Lu) is made. The actinide element is found to reside above the mean N₅ motexafinplane, and the larger the cation, the greater the observed out-of-plane displacement. It is concluded that theactinium(III), curium(III), and lawrencium(III) cations are tightly bound to the macrocyclic skeleton, yielding stablestructures. However, the calculated metal-ligand gas-phase binding energy for An-Motex²⁺ is about 1-2 eV lowerthan that of Ln-Motex²⁺, implying a lower stability of An-Motex²⁺ compared to Ln-Motex²⁺. Results including solventeffects imply that Ac-Motex²⁺ is the most stable complex in aqueous solution and should be the best candidate forexperimentalists to get stable actinide(III) motexafin complexes.