Oxo–Group‐14‐Element Bond Formation in Binuclear Uranium(V) Pacman Complexes

Simple and versatile routes to the functionalization of uranyl‐derived U V –oxo groups are presented. The oxo‐lithiated, binuclear uranium(V)–oxo complexes [{(py) 3 LiOUO} 2 (L)] and [{(py) 3 LiOUO}(OUOSiMe 3 )(L)] were prepared by the direct combination of the uranyl(VI) silylamide “ate” complex [Li(py) 2 ][(OUO)(N”) 3 ] (N”=N(SiMe 3 ) 2 ) with the polypyrrolic macrocycle H 4 L or the mononuclear uranyl (VI) Pacman complex [UO 2 (py)(H 2 L)], respectively. These oxo‐metalated complexes display distinct UO single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo–stannylated complexes [{(R 3 Sn)OUO} 2 (L)] (R= n Bu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium–oxo‐group exchange occurred in reactions with [TiCl(O i Pr) 3 ] to form U‐OC bonds [{(py) 3 LiOUO}(OUO i Pr)(L)] and [( i PrOUO) 2 (L)]. Overall, these represent the first family of uranium(V) complexes that are oxo‐functionalised by Group 14 elements.