Mononuclear Uranium and Heterobimetallic Actinide (An=Th, U) Alkoxides with Divalent Group 14 Elements (M^II=Ge, Sn, Pb)

When compared to main group and lanthanide elements, the heterobimetallic alkoxides of actinide elements with metals other than alkali metals are elusive. We report here for the first time alkoxide derivatives containing early actinides and the divalent group 14 elements. For this purpose in this work, co-alcoholysis reactions of silyl amides of divalent group 14 elements (M-II=Ge, Sn, Pb) and actinides (An(IV)=Th, U) were studied that resulted in the formation of [AnM((OBu)-Bu-t)(6)] (1-AnM) (An(IV)=Th, M-II=Ge, Sn, Pb; An(IV)=U, MII=Ge, Sn). A 2-electron redox reaction occurred in the U-IV-Pb(II )couple, which generated nearly quantitatively a U(V )alkoxide species and elemental lead. Precise adjustments of the stoichiometry in this reaction allowed to synthesize [U((OBu)-Bu-t)(5)Py] (3), amongst others in high yield. 3 and the U(IV )alkoxide [U((OBu)-Bu-t)(4)(Py)2] (4) described in this work represent first mononuclear U(IV )or U-V containing alkoxides. First promising attempts to use [U((OBu)-Bu-t)(5)Py] (3) as a starting material in co-alcoholysis reactions with divalent group 14 silylamides resulted in the formation of heterobimetallic UV-M-II alkoxides [UM((OBu)-Bu-t)(7)] (M-II=Ge, Sn, Pb) amongst others. All compounds described in this study were thoroughly characterized by multi-nuclear NMR and IR spectroscopic investigations, single crystal X-ray diffraction data, and CHN- analysis.