Research data for paper: Thorium- and Uranium-Mediated C–H Activation of a Silyl-Substituted Cyclobutadienyl Ligand

Data for paper published in Inorganic Chemistry Dec 2022 <br> CIF files and checkcif files for all compounds. <br> Abstract Cyclobutadienyl complexes of the f-elements are a relatively new yet poorly understood class of sandwich and half-sandwich organometallic compounds. We now describe cyclobutadienyl transfer reactions of the magnesium reagent [(η4-Cb'''')Mg(THF)3] (<strong>1</strong>), where Cb'''' is tetrakis(trimethylsilyl)cyclobutadienyl, toward thorium(IV) and uranium(IV) tetrachlorides. The 1:1 stoichiometric reactions between <strong>1</strong> and AnCl4 proceed with intact transfer of Cb'''' to give the half-sandwich complexes [(η4-Cb'''')AnCl(μ-Cl)3Mg(THF)3] (An = Th, <strong>2</strong>; An = U, <strong>3</strong>). Using a 2:1 reaction stoichiometry produces [Mg2Cl3(THF)6][(η4-Cb'''')An(η3-C4H(SiMe3)3-κ-(CH2SiMe2)(Cl)] (An = Th, [Mg2Cl3(THF)6][<strong>4</strong>]; An = U [Mg2Cl3(THF)6][<strong>5</strong>]), in which one Cb'''' ligand has undergone cyclometalation of a trimethylsilyl group, resulting in the formation of an An–C σ-bond, protonation of the four-membered ring, and an η3-allylic interaction with the actinide. Complex solution-phase dynamics are observed with multinuclear nuclear magnetic resonance spectroscopy for both sandwich complexes. A computational analysis of the reaction mechanism leading to the formation of <strong>4</strong> and <strong>5</strong> indicates that the cyclobutadienyl ligands undergo C–H activation across the actinide center.