Influence of Alkali Metal Cations in the Formation of the Heterobimetallic Actinide tert-Butoxides [AnM3(OtBu)7] and [AnM2(OtBu)6] (AnIV = Th, U; MI = Li, Na, K, Rb, Cs)

<p>These are the raw data the compound <strong>ThNa3</strong>, refined as an inversion twin. The following is the abstract of the corresponding paper.</p> <p>Heterobimetallic <em>tert</em>-butoxides of alkali metal cations and tetravalent actinide centers exhibit two distinctive structural motifs, [AnM₂(O<em>^t</em>Bu)₆] and [AnM₃(O<em>^t</em>Bu)₇] (An^IV = Th, U and M^I = Li, Na, K, Rb, Cs), evidently govern by the size of the alkali metal ions. Both [AnM₃(O<em>^t</em>Bu)₇] <strong>AnM3 </strong>(An^IV&nbsp;=&nbsp;U, M^I&nbsp;=&nbsp;Li; An^IV&nbsp;=&nbsp;Th, M^I&nbsp;=&nbsp;Li, Na) and<strong> </strong>[AnM₂(O<em>^t</em>Bu)₆] <strong>AnM2</strong> (An^IV&nbsp;=&nbsp;U, M^I&nbsp;=&nbsp;Na&nbsp;&ndash; Cs; An^IV&nbsp;=&nbsp;Th, M^I&nbsp;=&nbsp;K&nbsp;- Cs) compounds are obtained in nearly quantitative yields by reacting the actinide and alkali metal silyl amides with excess of <em>tert</em>-butyl alcohol. The <strong>AnM3</strong> complexes form a cubane-type coordination motif, whereas the <strong>AnM2</strong> complexes display a geometry resembling two face-shared bipyramids. The sodium derivatives of thorium and uranium (<strong>ThNa3</strong> and <strong>UNa2</strong>) allow to determine the structural transition threshold as function of the ratio of the ionic radii, r_i(An^IV)/r_i(M^I). The <strong>AnM3</strong> complexes are formed for ratios above 0.92 and the <strong>AnM2</strong> type is formed for ratios below 0.87. All compounds are unambiguously characterized in both solution and the solid-state via NMR and IR spectroscopic studies and single crystal X-ray diffraction analyses, respectively.</p>