Chemical structure and bonding in a thorium(iii)-aluminum heterobimetallic complex.
Chemical structure and bonding in a thorium(iii)-aluminum heterobimetallic complex.
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DOI：
10.1039/c8sc01260a
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发表时间：
2018-05-14
期刊：
影响因子：
8.4
通讯作者：
Arnold J
中科院分区：
文献类型：
--
作者：
Altman AB;Brown AC;Rao G;Lohrey TD;Britt RD;Maron L;Minasian SG;Shuh DK;Arnold J
我们描述了[Th（iii）]-[Al]和[U（iii）]-[Al]双金属化合物的合成，证明了An→Al相互作用，其中锕系元素作为电子供体。钍在元素周期表上处于一个独特的位置。一方面，几乎没有证据表明它的5 f轨道像其他早期锕系元素一样成键;另一方面，它的化学性质与刘易斯酸性过渡金属不同。为了深入了解Th的潜在电子结构并发展整个锕系元素系列的趋势，研究具有可能参与非静电金属-配体相互作用的价电子的Th（iii）和Th（ii）系统是有用的，尽管只有少数已知的此类系统。为了扩大低价化合物的范围并更深入地了解Th的电子结构，我们针对含有金属-金属键的锕系元素配合物。本文报道了由二叔丁基锡负载的Th（iv）二卤化物（Cp = 2 ThCl 2）与阴离子氢化铝盐[K（H3 AlC（SiMe 3）3）（1）]反应合成Th-Al双金属化合物。[Th（iv）]（Cl）-[Al]产物的还原产生[Th（iii）]-[Al]配合物[Cp‡ 2 Th（μ-H3）AlC（SiMe 3）3（4）]。U（iii）类似物[Cp <$2U（μ-H3）AlC（SiMe 3）3（5）]可以从U（iii）卤化物起始原料直接合成。4的电子顺磁共振研究表明未成对电子和Al原子之间的超精细相互作用表明自旋密度从Th金属中心到Al的离域。密度泛函理论和原子分子计算证实了4和5中An→Al相互作用的存在，这代表了An→M相互作用的第一个例子，其中锕系元素表现为电子供体。
We describe the syntheses of [Th(iii)]–[Al] and [U(iii)]–[Al] bimetallics that demonstrate An→Al interactions where the actinide behaves as an electron donor. Thorium sits at a unique position on the periodic table. On one hand, there is little evidence that its 5f orbitals engage in bonding as they do in other early actinides; on the other hand, its chemistry is distinct from Lewis acidic transition metals. To gain insight into the underlying electronic structure of Th and develop trends across the actinide series, it is useful to study Th(iii) and Th(ii) systems with valence electrons that may engage in non-electrostatic metal–ligand interactions, although only a handful of such systems are known. To expand the range of low-valent compounds and gain deeper insight into Th electronic structure, we targeted actinide bimetallic complexes containing metal–metal bonds. Herein, we report the syntheses of Th–Al bimetallics from reactions between a di-tert-butylcyclopentadienyl supported Th(iv) dihalide (Cp‡2ThCl2) and an anionic aluminum hydride salt [K(H3AlC(SiMe3)3) (1)]. Reduction of the [Th(iv)](Cl)–[Al] product resulted in a [Th(iii)]–[Al] complex [Cp‡2Th(μ-H3)AlC(SiMe3)3 (4)]. The U(iii) analogue [Cp‡2U(μ-H3)AlC(SiMe3)3 (5)] could be synthesized directly from a U(iii) halide starting material. Electron paramagnetic resonance studies on 4 demonstrate hyperfine interactions between the unpaired electron and the Al atom indicative of spin density delocalization from the Th metal center to the Al. Density functional theory and atom in molecules calculations confirmed the presence of An→Al interactions in 4 and 5, which represents the first examples of An→M interactions where the actinide behaves as an electron donor.
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影响因子：
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通讯作者：
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