Hohloch Stephan, Pankhurst James R, Jaekel Esther E, Parker Bernard F, Lussier Daniel J, Garner Mary E, Booth Corwin H, Love Jason B, Arnold John
Department of Chemistry, University of California, Berkeley, California 94720, USA.
Dalton Trans. 2017 Sep 12;46(35):11615-11625. doi: 10.1039/c7dt02728a.
We report the coordination chemistry of the tripodal tris[2-amido(2-pyridyl)ethyl]amine ligand, L, with thorium(iv) and uranium(iv). Using a salt-metathesis strategy from the potassium salt of this ligand, K3L, new actinide complexes were isolated, namely the dimeric thorium complex [ThCl(L)] (1) and the monomeric uranium complex UI(THF)(L) (2); under different crystallisation conditions, the dimeric uranium complex is also isolated, [UI(L)] (2-dimer). With the aim of studying electronic phenomena such as magnetic exchange between two actinide ions, we have synthesised the first examples of dinuclear, quinoid-bridged actinide complexes from dianionic 2,5-bis[2,6-(diisopropyl)anilide]-1,4-benzoquinone (QDipp) and 2,5-bis[2-(methoxy)anilide]-1,4-benzoquinone (QOMe) ligands. The resulting complexes are [Th(L)]Q (3), [Th(THF)(L)]Q (5) and [U(L)]Q (6). The targeted [U(L)]Q complex (4) could not be isolated. All isolated complexes have been characterised by spectroscopic methods and X-ray crystallography. The uranium(iv) complexes 2-dimer and 6 have been studied by SQUID magnetometry but indicate that there is negligible magnetic exchange between the two uranium(iv) ions. The reduced form of 6, [K(18-c-6)][6-] is unstable and highly sensitive, but X-ray crystallography indicates that it is a novel UU complex bridged by a quinoid-radical.
我们报道了三脚架型三[2-氨基（2-吡啶基）乙基]胺配体L与钍（IV）和铀（IV）的配位化学。通过盐复分解策略，从该配体的钾盐K₃L出发，分离得到了新的锕系配合物，即二聚钍配合物[ThCl(L)]（1）和单体铀配合物UI(THF)(L)（2）；在不同的结晶条件下，还分离得到了二聚铀配合物[UI(L)]（2-二聚体）。为了研究诸如两个锕系离子之间的磁交换等电子现象，我们从双阴离子2,5-双[2,6-（二异丙基）苯胺基]-1,4-苯醌（QDipp）和2,5-双[2-（甲氧基）苯胺基]-1,4-苯醌（QOMe）配体合成了双核、醌桥联锕系配合物的首例。得到的配合物为[Th(L)]Q（3）、[Th(THF)(L)]Q（5）和[U(L)]Q（6）。目标[U(L)]Q配合物（4）未能分离得到。所有分离得到的配合物均通过光谱方法和X射线晶体学进行了表征。通过超导量子干涉仪磁强计对铀（IV）配合物2-二聚体和6进行了研究，但结果表明两个铀（IV）离子之间的磁交换可忽略不计。6的还原形式[K(18-c-6)][6⁻]不稳定且高度敏感，但X射线晶体学表明它是一种由醌自由基桥联的新型UU配合物。
