Laboratoire de Reconnaissance Ionique et Chimie de Coordination, SCIB, UMR-E3 CEA-UJF, INAC, CEA-Grenoble, 17 rue des Martyrs, F-38054 Grenoble Cedex 09.
J Am Chem Soc. 2013 Aug 14;135(32):12101-11. doi: 10.1021/ja405815b. Epub 2013 Aug 5.
The new homoleptic ate U(III) siloxide [K(18c6)][U(OSi(O(t)Bu)3)4] 2 was prepared in 69% yield by reduction of [U(OSi(O(t)Bu)3)4] 3 with KC8. The reaction of the neutral U(III) siloxide complex [U(OSi(O(t)Bu)3)2(μ-OSi(O(t)Bu)3)]2 1 with adamantyl azide leads to the isolation of the dinuclear U(VI) imido complex [U2(NAd)4(OSi(O(t)Bu)3)4] 4. The X-ray crystal structure shows the presence of a "cation-cation interaction" between the two U(NAd)2 groups. In contrast the reactions of 2 with the trimethylsilyl and adamantyl azides afford the U(V) imido complexes [K(18c6)][U(NSiMe3)(OSi(O(t)Bu)3)4] 5-TMS and [K(18c6)][U(NAd)(OSi(O(t)Bu)3)4] 5-Ad pure in 48% and 66% yield, respectively. The reaction of 2 with CsN3 in THF at -40 °C yields a mixture of products from which the azido U(IV) complex [K(18c6)][U(N3)(OSi(O(t)Bu)3)4] 7 and the μ-nitrido diuranium(V) complex [KU(μ-N)(OSi(O(t)Bu)3)]2 8 were isolated. The crystal structure of 8 shows the presence of a rare U2N2 core with two nitrido atoms bridging two uranium centers in a diamond-shaped geometry. In contrast, the reaction of 1 with CsN3 affords the diuranium(IV) complex Cs{(μ-N)[U(OSi(O(t)Bu)3)3]2} 9 presenting a nitrido ligand bridging two uranium and one cesium cations. These results show the importance of the coordination environment in the outcome of the reaction of U(III) with azides.
新的同配位的 U(III) 硅氧烷配合物[K(18c6)][U(OSi(O(t)Bu)3)4]2 是通过 KC8 还原[U(OSi(O(t)Bu)3)4]3 以 69%的产率制备的。中性 U(III) 硅氧烷配合物[U(OSi(O(t)Bu)3)2(μ-OSi(O(t)Bu)3)]2 1 与金刚烷基叠氮化物的反应导致二核 U(VI) 亚胺配合物[U2(NAd)4(OSi(O(t)Bu)3)4]4 的分离。X 射线晶体结构显示出两个U(NAd)2基团之间存在“阳离子-阳离子相互作用”。相比之下，2 与三甲基硅基和金刚烷基叠氮化物的反应以 48%和 66%的产率分别得到 U(V) 亚胺配合物[K(18c6)][U(NSiMe3)(OSi(O(t)Bu)3)4]5-TMS 和[K(18c6)][U(NAd)(OSi(O(t)Bu)3)4]5-Ad。2 与 CsN3 在 THF 中的反应在-40°C 下得到产物的混合物，从中分离出叠氮 U(IV) 配合物[K(18c6)][U(N3)(OSi(O(t)Bu)3)4]7 和μ-亚硝酰二铀(V)配合物[KU(μ-N)(OSi(O(t)Bu)3)]28。8 的晶体结构显示出存在罕见的 U2N2 核，其中两个亚硝酰原子以菱形几何形状桥接两个铀中心。相比之下，1 与 CsN3 的反应得到二铀(IV)配合物 Cs{(μ-N)[U(OSi(O(t)Bu)3)3]2}9，其中一个亚硝酰配体桥接两个铀和一个铯阳离子。这些结果表明 U(III) 与叠氮化物反应的结果中配位环境的重要性。
