Synthesis and Reactivity of Trivalent Tp*U(CH2Ph)2(THF): Insertion vs Oxidation at Low-Valent Uranium–Carbon Bonds

The synthesis of a rare uranium­(III) bis­(benzyl), Tp*U­(CH2Ph)2(THF) (2), was achieved by salt metathesis of Tp*UI2(THF)2 with 2 equiv of KCH2Ph at low temperature. This was characterized by 1H NMR, infrared, and electronic absorption spectroscopy as well as X-ray crystallography. Addition of benzophenone to 2 forms the uranium­(IV) radical coupling product Tp*U­(CH2Ph)2(OC­(Ph)2CH2Ph) (3), whereas N3Mes produces the imido derivative Tp*U­(NMes)­(CH2Ph)­(THF) (4). Adding a further 1 equiv of N3Mes to tetravalent 4 results in U–C insertion to form the U­(IV) triazenido species Tp*U­(NMes)­[(CH2Ph)­N3(Mes)-κ2N1,2]­(THF) (5). Compound 2 also reacts with the redox-active 4,6-di-tert-butyl-2-[(2,6-diisopropylphenyl)­imino]­quinone (DIPPiq) to form the oxidized amido­(phenolate) Tp*U­(CH2Ph)­(DIPPap) (6).