Evidence for covalence in a N-donor complex of americium(III)
Evidence for covalence in a N-donor complex of americium(III)
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DOI：
10.1039/c3dt50953b
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发表时间：
2013-01-01
影响因子：
4
通讯作者：
Denecke, Melissa A.
中科院分区：
文献类型：
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作者：
Adam, Christian;Kaden, Peter;Denecke, Melissa A.
n -供体配体，如烷基化双三嗪基吡啶（BTPs），在镧系元素存在下对锕系元素络合的选择性的分子起源仍然很大程度上不清楚。对带有N-15标记配体的Am(nPrBTP)(3)（3+）配合物的核磁共振研究表明，与镧系（III）配合物和自由配体相比，它在N-15化学位移方面表现出很大的差异。该配合物的核磁共振化学位移的温度依赖性表明其具有弱顺磁性。这一事实和观察到的结合氮原子的大化学位移使我们得出结论，所报道的Am(III) n给体配合物中的金属配体键具有比镧系配合物更大的共价份额。这可以解释观察到的选择性。
The molecular origin of the selectivity of N-donor ligands, such as alkylated bis-triazinyl pyridines (BTPs), for actinide complexation in the presence of lanthanides is still largely unclear. NMR investigations of an Am(nPrBTP)(3)(3+) complex with a N-15 labelled ligand showed that it exhibits large differences in N-15 chemical shift for coordinating N-atoms in comparison to both lanthanide(III) complexes and the free ligand. The temperature dependence of NMR chemical shifts observed for this complex indicates a weak paramagnetism. This fact and the observed large chemical shift for bound nitrogen atoms allow us to conclude that metal-ligand bonding in the reported Am(III) N-donor complex has a larger share of covalence than in lanthanide complexes. This may account for the observed selectivity.