School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
Nat Chem. 2017 Jun;9(6):578-583. doi: 10.1038/nchem.2692. Epub 2016 Dec 26.
Our knowledge of actinide chemical bonds lags far behind our understanding of the bonding regimes of any other series of elements. This is a major issue given the technological as well as fundamental importance of f-block elements. Some key chemical differences between actinides and lanthanides-and between different actinides-can be ascribed to minor differences in covalency, that is, the degree to which electrons are shared between the f-block element and coordinated ligands. Yet there are almost no direct measures of such covalency for actinides. Here we report the first pulsed electron paramagnetic resonance spectra of actinide compounds. We apply the hyperfine sublevel correlation technique to quantify the electron-spin density at ligand nuclei (via the weak hyperfine interactions) in molecular thorium(III) and uranium(III) species and therefore the extent of covalency. Such information will be important in developing our understanding of the chemical bonding, and therefore the reactivity, of actinides.
我们对锕系元素化学键的了解远远落后于对任何其他元素系列键合态的理解。鉴于 f 区元素在技术和基础方面的重要性，这是一个主要问题。锕系元素和镧系元素之间以及不同锕系元素之间的一些关键化学差异可以归因于共价键合程度的微小差异，即 f 区元素与配位配体之间共享电子的程度。然而，对于锕系元素，几乎没有直接测量这种共价键的方法。在这里，我们报告了首例锕系元素化合物的脉冲电子顺磁共振波谱。我们应用超精细亚层相关技术来量化分子三价钍和三价铀物种中配体原子核处的电子自旋密度（通过弱超精细相互作用），从而量化共价键的程度。这种信息对于我们理解锕系元素的化学键合以及因此的反应性将非常重要。
