Falcone Marta, Scopelliti Rosario, Mazzanti Marinella
Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland.
J Am Chem Soc. 2019 Jun 19;141(24):9570-9577. doi: 10.1021/jacs.9b02235. Epub 2019 Apr 24.
Here we show that a scaffold combining siloxide ligands and a bridging oxide allows the synthesis and characterization of the stable dinuclear uranium(IV) hydride complex [K{U(OSi(O Bu))(μ-H)}], 2, which displays high reductive reactivity. The dinuclear bis-hydride 2 effects the reductive coupling of acetonitrile by hydride transfer to yield [K{U(OSi(O Bu))(μ-κ-NC(CH)NCHCH)}], 3. Under ambient conditions, the reaction of 2 with CO affords the oxomethylene reduction product [K{U(OSi(O Bu))(μ-O)}], 4, that can further add H to afford the methoxide hydride complex [K{U(OSi(O Bu))(μ-O)(μ-H)}], 5, from which methanol is released in water. Complex 2 also effects the direct reduction of CO to the methoxide complex 5, which is unprecedented in f element chemistry. From the reaction of 2 with excess CO, crystals of the bis-formate carbonate complex [K{U(OSi(O Bu))(μ-HCOO)}], 6, could also be isolated. All the reaction products were characterized by X-ray crystallography and NMR spectroscopy.
在此我们表明，一种结合了硅氧化物配体和桥连氧化物的支架能够实现稳定的双核氢化铀(IV)配合物[K{U(OSi(O Bu))(μ-H)}]（2）的合成与表征，该配合物具有高还原反应活性。双核双氢化物2通过氢化物转移实现乙腈的还原偶联，生成[K{U(OSi(O Bu))(μ-κ-NC(CH)NCHCH)}]（3）。在环境条件下，2与CO反应得到氧亚甲基还原产物[K{U(OSi(O Bu))(μ-O)}]（4），其可进一步添加H得到甲醇氢化物配合物[K{U(OSi(O Bu))(μ-O)(μ-H)}]（5），5在水中会释放出甲醇。配合物2还能将CO直接还原为甲醇盐配合物5，这在f元素化学中是前所未有的。从2与过量CO的反应中，还可分离出双甲酸碳酸酯配合物[K{U(OSi(O Bu))(μ-HCOO)}]（6）的晶体。所有反应产物均通过X射线晶体学和核磁共振光谱进行了表征。
